CURRENT TRENDS IN COMMODITY SCIENCE ANALYSIS AND CONSUMER ACCEPTANCE OF FOOD PRODUCTS

EDITOR

Hanna Śmigielska POZNAŃ 2013

Title: Current trends in Commodity Science: Analysis and consumer acceptance of food products

Editor: Hanna Śmigielska

Reviewers: Róża Biegańska-Marecik Daniela Gwiazdowska Marta Ligaj Alina Matuszak-Flejszman Stanisław Popek Urszula Samotyja

Copyright by: Poznań University of Economics, Faculty of Commodity Science Al. Niepodległości 10, 61-875 Poznań ISBN 978-83-911169-7-5

Printed by: Poznań University of Economics Print Shop, 2013 ul. Towarowa 53, 61-896 Poznań, Tel. 48 618543806

2

CONTENTS Introduction ....................................................................................................................... 5 Małgorzata Miśniakiewicz, Michał Halagarda Regional and traditional products on the market of bread – the analysis of consumers’ preferences .......................................................................................................................... 7 Joanna Ptasińska-Marcinkiewicz Correlations between selected sheep milk quality parameters ........................................... 24 Monika Radzymińska, Bożena Garbowska, Dominika Jakubowska Quality of traditional and conventional Polish Ham ............................................................... 36 Joanna Jasnowska-Małecka, Martyna Mocek The influence of lactic acid bacteria on milk proteins ........................................................ 45 Wanda Kudełka Comparative analysis of profile of fatty acids in selected traditional polish cheeses made from goats’ and cows’ milk ............................................................................................... 60 Iga Rybicka, Anna Gliszczyńska-Świgło HPLC determination of water-soluble vitamins in grain products ...................................... 70 Katarzyna Włodarska, Katarzyna Pawlak-Lemańska, Ewa Sikorska Quality of pure apple juices and apple juices with additives evaluated by their physicochemical properties ............................................................................................... 81 Ewa Marjanska, Elwira Tymoszuk, Maria Szpakowska Investigation of sour substances by five-channel potentiometric taste sensor containing ASSEs .............................................................................................................................. 91 Maria Szpakowska, Ewa Marjańska, Elwira Tymoszuk Taste qualities estimation by taste sense and electrochemical sensors .............................. 104 Magdalena Duc Food adulteration as exampled by processed meat products............................................. 116 Inga Klimczak, Paulina Ćwiklińska The effect of pomegranate juice on enzymatic browning of cloudy apple juice ................ 125 Krzysztof Melski The use of microwave ovens in the households of students of the faculty of commodity science in the last decade................................................................................................. 140

3

4

Introduction Nowadays, the interest and demand for good quality food is high and continues to grow, especially when people recognize their potential to improve the health and well-being. There are many questions and concerns in this area, as well as lurking threats and deception to the unaware consumer. It is important to make sensible decisions about all food products that we are able to choose from on the market. Obviously that it is difficult and should be based on reliable scientific evidence. Food quality depends on the method of manufacture, obtaining, processing and preparation of ready meals as well as their storage and conditions of sale. Every step of this food production chain requires research and control actions to ensure the best quality of final product. Acceptance of new and traditional food products by consumers is also an important factor influencing the size of the food market. Studies in that areas are conducted by researchers from different scientific communities related to food and commodity sciences. This publication includes articles regarding analysis of the food and its ingredients, consumer acceptance of traditional food and regional products as well as the quality and adulteration food products. Moreover two papers depict a study about electronic sensors. Finally one of the articles which is based on several years survey research among students of the Faculty of Commodity Sciences informs how today's world perceives usage of microwave ovens to prepare food. Hanna Śmigielska

5

6

REGIONAL AND TRADITIONAL PRODUCTS ON THE MARKET OF BREAD – THE ANALYSIS OF CONSUMERS’ PREFERENCES Małgorzata Miśniakiewicz, Michał Halagarda Cracow University of Economics, Faculty of Commodity Science, Department of Food Commodity Science, ul. Sienkiewicza 5, 33-033 Cracow, Poland,

Abstract: Traditional and regional bread is the group of product increasingly appearing on the market which can be a counterweight to conventional bread produced on a massive scale. It is based on centuries-old traditions formula and its baking technology remains constant. The main aim of the research was to analyze consumer preferences on the market of regional products, paying particular attention to regional and traditional breads available on the market in the Malopolska Region and to reveal the most important determinants of bread choice and factors hindering it. Due to the steadily decreasing consumption of bread in Poland, the objective of this study was also to diagnose how the traditional bread may help in reversing this alarming trend and contribute to promotion of the fashion for consumption of nutritionally valuable, regional products. In the experimental part of the study using the method of direct interviews and a survey carried out via Internet it was possible to identify the specified behavior determinants of Polish consumers on the market of traditional bread, the way to define this term, reasons to buy this type of bread and the availability of information about regional and traditional bread. Consumer preferences have been analysed in terms of product range, prices and places to buy this food category. The positive attitude of consumers towards regional bakery products should be considered as a factor encouraging a further development of the demand for this category of food. However, this requires a range of actions aimed at i.e. diversification of its sales logistics and creation of a reliable information system about its properties and positive effects on the human body. Keywords: traditional and regional bread products, consumers’ preferences

INTRODUCTION The increased interest in regional and traditional food is one of the trends that emerged a few years ago on the market not only in Poland but also in Western Europe. It has systematically become a part of the new models of consumer behavior [Biłasiewicz 2004, Łuczka-Bakuła 2004, Boruc 2006, Czarnecka-Skubina 2011, Winawer and Wujec 2010, Trichopoulou, Soukara, and Vasilopoulou 2007]. It directly stems from the effort to preserve and present the values of the cultural heritage and long-standing traditions of the regions [Vanhonacker et al.

7

2010]. It also a practical implementation of assumptions of many trends, being of interest to the ever-expanding group of modern consumers, namely:  slow food – it assumes the protection of the right to taste, the care of the traditional regional cuisine and return to the pleasure of eating, lost as a result of the accelerating pace of life, • glocalization - the creation of unique regional products and brands, which are then distributed globally; it is related to the promotion of regional and often organic farming and the development of local food producers, • sustainability - sustainable development, conscious management of natural resources with care for future generations; currently ecology becomes the duty of everyone, • well-being - a conscious choice of diet, local, traditional products, often from organic farms in conjunction with a proactive lifestyle, regular sports training, new, health-related dietary habits as a prevention of civilization diseases [Sojkin et al. 2009, Slow Food in 2012, Lengard et al. 2011]. Both in Poland and other countries, a number of attributes resulting from the specific characteristics of the raw materials and the methods of production as well as place of the origin are assigned to traditional/regional food. Consumers perceive the consumption of traditional foods as an opportunity to satisfy their hedonistic aspirations of seeking new taste sensations. They also see it as a chance to raise their self-esteem, because this food is often classified into the premium segment [Żakowska-Biemans 2012, Guerrero et al. 2009]. One of the products that have been increasingly popular among buyers is regional bread, produced basing on traditional recipes. According to the literature analysis, this product has been rarely the subject of research [Korfel 2008]. Bakery products, especially bread, are of the key importance in the diet of an average Pole - a valuable source of building, energetic and regulating ingredients. Despite significant changes in dietary habits of Poles, bread is still seen in our country as a natural part of everyday diet, something acceptable and necessary, even though the consumption is steadily declining. What is intuitively known, confirms the CSO - bread is acquired by over 96% of households [GUS 2012B]. That is more than any other product. Bakery products are present in almost every Polish home. The most popular are mixed flour bakery products, then products made of wheat flour. Rye bread is still, despite the indisputable nutritional value is only a supplement in a diet of average Pole [Gąsiorowski 2010, Czerwińska 2010]. Among the commercially available breads more often an additional category can be distinguished - regional / traditional breads, often described with adjectives „chłopski”, „staropolski”, „swojski” to enhance their 8

naturalness and therefore uniqueness. Unfortunately, only some of them meet the requirements that are set for the product group. The others are kinds of substitutes that spoil the traditional bread market. Regional bread manufacturing is a chance for many small bakeries that are predominant in Poland. Thanks to the regional products made basing on traditional recipes, they can get extra income from their business and gain a loyal customers, not only on a local scale. Baked in a traditional manner and according to local recipes, regional bread becomes synonymous of “healthy”, natural food in the best sense of that word. The examples include: the traditional rye bread produced with a use of sourdough, bread with the addition of potatoes or “Kukiełki” - wheat rolls baked in Krakow and Krakow region’s bakeries for over four hundred years, including the Regional Bakery in Liszki. The innovative nature of this group of bread is noteworthy. It may become an alternative to bread conventionally produced on a large scale with a use of ready bakery mixes - bread of a unified composition, taste, smell and the level of quality that, regardless of the bakery making it, looks and tastes very much alike [Rothkaehl 2012, Giannou, Kessoglou, Tzia 2003]. The main aim of the research was to analyze consumer preferences on the market of regional products, paying particular attention to regional and traditional breads available on the market in the Malopolska Region and to reveal the most important determinants of bread choice or factors hindering it. Due to the steadily decreasing consumption of bread in Poland, the objective of this study was also to diagnose how the traditional bread may help in reversing this alarming trend and contribute to promotion of the fashion for consumption of nutritionally valuable, regional products.

MATERIAL AND METHODS Surveys of consumer preferences concerning selection and consumption of traditional products with a particular focus on regional and traditional breads were held in OctoberNovember 2012 on a group of 135 respondents from the Malopolska Region (94 traditional questionnaires were conducted through direct interviews and 41 surveys were obtained electronically). The main part of the questionnaire consisted of 13 closed questions. Most of them, however, offered the possibility of broadening the answer with respondent’s personal feelings and preferences. These were the questions about the sources of information on regional bakery products, circumstances and causes of their consumption, reasons for assigning the product to the traditional bakery products, terms that are associated with this type of products and the possible factors that would encourage consumers to choosing 9

traditional, regional bread more often. 60% of the respondents were women and 40% men. The majority of the respondents (42%) were 25-35 years old. The next most numerous age groups included people under 25 years old (27%) and 36-50 years old (19%). The smallest group of respondents were people above 65 years old (3%). The vast majority of respondents had a university degree (39%) and incomplete higher education (33%). Other surveyed people got secondary education (24%) or vocational secondary education (3%). The examined population was dominated by residents of cities with over 500 thousand (36%) and 100-500 thousand inhabitants (14%). At the same time 17% of respondents were rural residents. The collected empirical material was analyzed with a use of the Microsoft Office Excel 2010 spreadsheet and the methods of descriptive statistics.

RESULTS AND DISCUSSION The research revealed that the inhabitants of the Malopolska Region understand terms: "regional“ and "traditional” food as a category of foods available on the market. 126 out of 135 questioned people, which is 93% of the respondents, claimed that they can distinguish these types of food from conventional products. This might be due to the long history of the Malopolska Region and great variety of traditional products available on the local market. The obtained results are similar to the results of other authors, such as Żakowska-Biemans and Kuc [2009] who determined the knowledge of that groups of food at the level of 96% and Surdel et al. [Surdel, Sobczyk and Kogut 2009] at the level of 94%. Knowledge of these categories of products is not always reflected in purchasing decisions of the Malopolska Region residents. Among the respondents 82% do purchase traditional and regional food. In this group women aged 25-35 are predominant. Among men, this type of food is the most frequently chosen by people in the age of 36-50 years. Some people, out of the 18% respondents who were not buying traditional food, explained that they produce traditional food themselves at their homes. They, for instance, bake bread or prepare ready meals such as stew or dumplings, often basing on the family recipes passed from generation to generation. The best-selling Polish regional products most often chosen by the Malopolska inhabitants are meat products, particularly traditional hams and sausages, such as Lisiecka sausage (52% of responses) and honey (48% of responses). The third position belongs to the regional bakery products (including confectionery products) being the subject of this study. They were selected by 42% of the respondents. On the list of traditional products willingly chosen by 10

surveyed people dairy products such as oscypek, bryndza, bundz were also to be found. Their purchase was declared by 51 people, which is 38% of the respondents. The full list of traditional products the most frequently purchased by residents of the Malopolska Region is shown in Figure 1.

Figure 1. The best-selling Polish regional products in Malopolska Region Source: own research

The smallest interest of respondents considering the willingness to purchase traditional products was focused on soft drinks and traditional butter and oils – only 8 respondents out of 135. The obtained results are to some extent different from those presented by Żakowska-Biemans and Kuc [Żakowska-Biemas and Kuc 2009], which showed that the respondents as the most famous traditional products category considered cheese (71% of indications), then meat products (52% of indications) and bakery products (33% of indications). However, the most recognizable groups of traditional food coincide. In turn, M. Sajdakowska and S. ŻakowskaBiemans [Sajdakowska and Żakowska-Biemans 2009] recognized the bread as a product that meets the criteria of the traditional foods the best. Analysis of the results of surveys in the field of traditional breads allowed to determine:  the frequency of acquisition of regional and traditional breads By analyzing the frequency of purchase of traditional bread (Fig. 2), it was found that the dominant group of respondents (38%) chooses it the most often a few times a month or a few times per week (24% of indications). At the same time, 12% of the respondents choose traditional bread products every day and most of these are older people over 65 years old, 11

while 4% of respondents never choose it when buying this kind of bread. In the survey, there were opinions that it is difficult to unambiguously determine whether a particular type of bread is a traditional bread in the full sense of these words because of the lack of an adequate, reliable labelling of products in this category.

Figure 2. The frequency of purchase of traditional bread Source: own research

Table 1 shows the socio-demographic characteristics of people who declare to buy traditional and regional bread because of its frequency taking into account such factors as gender, age, education and place of residence. Table 1. The socio-demographic characteristics of the Polish traditional breads consumers’ from Malopolska Region The declared frequency of the traditional bread The purchase [%] Socio-demographic number profile of a few a few once in of every respondents times a times a never 2-3 rarely people day week month months Gender: Female 6 29 40 3 11 11 82 Male 4 21 36 2 26 11 53 Age: Less than 25 years 3 50 33 0 11 3 36 25-35 years old 9 42 25 3 14 7 57 36-50 years old 12 72 16 0 0 0 25 51-65 years old 15 31 46 0 8 0 13 Over 65 years old 25 50 0 0 0 25 4

12

Education: Primary Vocational secondary Secondary Incomplete higher Higher Place of residence: Countryside Up to 20,000 20,000-50,000 50,000 -100,000 100,000-500,000 More than 500,000 Source: own research

0 4 33 45 53

0 0 6 6 7

0 25 55 18 49

0 50 36 56 23

0 25 0 4 4

0 0 1 9 13

0 0 0 7 4

23 13 16 16 19 48

0 16 23 6 0 15

13 38 50 25 37 50

61 31 31 62 53 21

26 0 0 0 0 0

0 15 0 0 5 10

0 0 0 6 5 4

Its analysis allows to know more accurately the profile of the active buyer and, on this basis, draw, for example an effective way to communicate, get information about the product to the customer group, position product on the market. The most often traditional bread was bought by consumers at the age of 36-50 years, women more willingly than men. The acquired data differentiate a bit traditional bread market in relation to the traditional food market as the general – due to Borkowska [Borkowska 2007] and Żakowska-Biemans and Kuc [ŻakowskaBiemnas and Kuc 2009] this kind of food is preferred by younger consumers in the age 30-39 years old. To examine the relationships between the scheduled socio-demographic characteristics of respondents and the frequency of bread’s purchase the Chi-square independence test was used. Inference was carried out at the level of significance of 0.05 for the appropriate groupings of data. In the case of rejection of the hypothesis of the variables independence further interpretation was based on the values of GC residue. The analysis showed that the gender and age of the respondents do not diversify the declaration of the frequency of purchase of regional bread. In the first case, the calculated value of the test was 3.59, and the second – 8.19. In both cases, there was no reason to reject the null hypothesis at the 0.05 level. The level of education of the respondents turned out to be a differentiating factor for the declaration of the frequency of purchase of bread. The calculated value of test, 17.40 gives the reason for rejection the null hypothesis at the 0.05 level. The values of the GC residue (table 2.) enable to establish that the respondents with incomplete higher education to a greater extent than other declare that they buy regional bread infrequently, and respondents with at most secondary and higher education show a stronger tendency to frequent acquisition of this type of bread. 13

Table 2. Correlation between education level and frequency of purchase (the number of GC residue)

Level of education

Purchase frequency Seldom GC residue

Often

Up to secondary eductation Not full higer education Higher education Source: own research

Very seldom

4.0

-0.2

-3.8

-9.3 5.3

8.0 -7.7

1.3 2.4

In addition, respondents' place of residence is a factor that varies the declaration of the frequency of purchase of regional bread. The calculated value of the test was 22.51 and this is the basis for a rejection of the null hypothesis at the 0.05 level. The values of the GC residue (table 3.) enable to establish that the inhabitants of small towns (up to 50,000) and large cities (more than 500,000) show a stronger tendency to frequent acquisition of bread. Table 3. Correlation between place of residence and purchase frequency (number of GC residue)

Place of residence

Often

Countryside City to 50,000 City 50,000-500,000 City more than 500,000 Source: own research

-4.1 3.3 -5.8

Purchase frequency Seldom Very seldom GC residue -1.3 5.4 -2.5 -0.8 -0.3 6.1

6.6

-9.0

2.4

It is worth noting that the frequency of traditional bread purchase grows in proportion with the educational level of respondents, particularly in the case of purchases a few times a week. This may result from a higher level of knowledge about traditional food, a greater interest in a balanced diet and greater accessibility to information on the subject. The obtained results confirm the research literature data [Vanhonacker et al. 2010, Żakowska-Biemans 2012].  Sources of information on traditional bread As a source of reliable information on traditional breads (it was able to choose up to three responses) in the first place, respondents indicate friends and family – 59%, and then the information submitted by seller in place of purchase of bread - 31% indications (which emphasizes the essence of human interaction in shaping attitudes in the market) and the Internet 26%. Detailed information on potential sources of information about regional bread is shown in Figure 3. 14

Figure 3. Sources of information on traditional and regional bread Source: own research

The special role in the transmission of information about regional bread play festivals and fairs with traditional and organic food (22% of indicates) such as organized in Cracow in June, from 2003 on an annual basis the feast of bread. Among the responses within the category of "other" respondents (5 persons) indicated their experience acquired over the years, the consumption of baked goods from various bakeries and bread taste memories from childhood.  the most important reasons for choosing traditional and regional bread Bread is included in products for general consumption so do not wonder that the most numerous respondents’ group (58% of indications) chooses the traditional bread every day, with no special occasion. Frequent opportunity to delve after the product are some of the festivals, offering tastings of traditional breads (34% of indications), family celebrations (22%), holidays (19%), or visits to the region (11%), which is a way of cultivating and transfer of traditions of the region.

15

Figure 4. Circumstances of traditional bread consumption Source: own research

 the main reasons for the purchase and consumption of regional breads In the hierarchy of factors for buying traditional bread in the first place with 51% of the indications emerged conviction that it is more natural than conventional bread. Secondly, respondents underlined the value of traditional flavors (41% of indications).

Figure 5. Main reasons for the selection and consumption of traditional bakery products Source: own research

22% of the respondents considered the traditional bread for more nutritive than conventional one, and 21% found it to be a prestigious product which consumption allows you not only to spice up your daily diet (17% of readings), but raises self-esteem and allows you to have the conviction that it is healthy and reasonably. Only 12% of the population of Malopolska 16

appreciated the role of the regional breads in supporting the development of the region and for transmission of traditions to future generations. Only 1 in 10 respondents claimed that traditional bread has a higher sensory quality than conventional bread. It definitely differs traditional bread from the rest kinds the traditional food segment, for which taste is the basic criterion for determining the purchasing decisions of consumers [Borowska 2007, Żakowska-Biemans and Kuc 2009, Żakowska-Biemans 2012, Lengard Almi et al. 2011, Vanhonacker et al., 2010].  the basics of assigning a particular product to traditional bread Respondents most often included the type of bread to traditional products on the basis of their own knowledge and experience (41% of indications). In second place was the information provided on the packaging of the product, possibly attached to the package leaflet (31%), and information provided by the seller (29% of indications). 5% of respondents frankly admitted that they are not able to recognize regional bread in the store. The full set of the basis of assigning a particular product to traditional bread is shown in Fig.6.

Figure 6. Reasons to recognize the bread as traditional one in the consumers’ perception Source: own research Respondents were allowed to provide a maximum of two answers to this question.

 preferred places to purchase traditional breads (fig. 7) Respondents as the most common place to buy regional bread indicated nearby shop (51% of indications). A large popularity in Malopolska is also purchase this type of bread directly from the manufacturer (42%) and with the same amount of indications of buying bread occasionally during the fairs and markets. This is confirmed in European comparative tests on

17

traditional foods and in the results of other authors’ analysis [Guerrero et al. 2009, 2010 Vanhonacker, Żakowska-Biemans 2012].

Figure 7. Favourite places to buy traditional breads Source: own research

 characteristics of traditional breads in the opinion of the respondents As the most important features of the traditional breads respondents recognized its naturalness (55% of indications) and unique taste and smell (35%), which, however, does not differentiate the traditional breads from conventional one in the opinion of the respondents in a significant way. It reveals ethnocentrism of Polish consumers, for whom the term "Polish bread" is the quintessence of Polish cuisine. The characteristics attributed to traditional bread by the inhabitants of Galicia are shown in Fig. 8.

Figure 8. Attributes of traditional bread in the opinion of inhabitants of the Malopolska Region Source: own research 18

It should be noted that a significant number of respondents consider traditional bread as the product difficult to diagnose (38% of indications), almost unavailable (33% of indications) and expensive (33% of indications). 28% of respondents said that traditional bread has a high nutritional value, and 17% that it is a product of the highest quality in the market of bread. Consumers from Galicia do not recognize this group of foods for a luxurious or fashionable, respectively, 7 and 5% indicated.  respondents’ subjective assessment of the traditional bread’s price Assessing the price of the traditional bread, 53% described it as being too high and 47% as being appropriate. Therefore, the price can be regarded as a barrier to the purchases of regional bakery products and their perception as a luxury, premium products. It may affect the propensity to buy these products, especially in a view of the steadily rising prices of bread and increasing share of expenditure on food [Żakowska-Biemans 2012]. On the other hand, lowering the price of the traditional bread could lead to the depreciation of its image as an everyday and at the same time unique product. • choice and availability of traditional bakery products on the local market Analyzing the issue of the diversity and availability of the traditional bakery products on the market in the Malopolska Region the respondents provided following answers sequentially: satisfactory-good-poor (Fig. 9). Only 5% of the surveyed people found the current availability of the traditional bread very good. On the other hand, a very poor opinion was given by 7% of the respondents. This proves the fact that traditional bread is not yet a widely available product.

Figure 9. Assessment of the selection and availability of the traditional bread in the Malopolska Region Source: own research

19

However, the determined consumer should not have much difficulty in reaching to and choosing the genuine traditional bread. At the same time, respondents emphasized the need to improve the situation in this regard, including the need for campaigns promoting the traditional bread and its manufacturers.  factors that would persuade respondents to more frequent purchase decisions and consumption of the regional and traditional bread The statement of changes that would encourage consumers from the Malopolska Region to buy and consume regional bakery products more often are shown in Figure 10.

Figure 10. Factors that would increase the level of purchases and consumption of traditional bakery products Source: own research

In the first place the surveyed pointed out the greater availability of the products in this food group (37% of respondents), followed by lower prices (26% of responses) and confirmation of the traditional bread’s quality with an appropriate certificate (17% of responses). Facilitation of the identification of this group of bakery products and assurance to buyers that they are purchasing the genuine and valuable product were indicated by 12% of the respondents. This proves that Polish consumers expect certain guarantees of the authenticity and unique character of traditional / regional bakery products. The results confirm the trends observed by other authors [Trichopoulou, Soukara, Vasilopoulou 2007, Żakowska-Biemans 2012, Vanhonacker et al. 2010].

20

CONCLUSIONS Traditional and regional bakery products are becoming more commonly to be found on the market. They are a counterweight to conventional products prepared on a mass scale. This groups of products are intended primarily for those who appreciate their uniqueness, naturalness along with an exceptional taste and flavor and longer lasting freshness. They are made with a use of local raw materials and according to traditional recipes. Although, the existing EU legislation on traditional food specify criteria for quality marks and scope of their protection, the term "traditional food" is not subjected to protection, being sometimes interpreted differently and often abused. The results of the consumer preferences study show that the Malopolska Region’s citizens recognize and appreciate the regional bread. They, however, sometimes have trouble with its identification. They associate the authentic, traditional bread with the best food of Polish cuisine and consider it to be the synonymous with Polish culture. Bakery products were on the third position among the most frequently purchased traditional products. Just after meat products and honey. It is mainly chosen by residents of larger cities with higher education. The largest percentage of respondents buys traditional bread several times a month. Then, there are people who purchase it a few times a week, every day and without a special occasion. The main sources of information on traditional bakery products involve friends and family, as well as data provided on the place of purchase and on the Internet. Traditional bread is valued for its naturalness, no addition of preservatives or improvers, traditional flavour and higher nutrients’ content in comparison to its conventional equivalent - produced on a large scale with lots of chemical compounds, from baking premixes and with a use of shortened processing methods to improve effectiveness. The respondents have a problem with the identification of the real traditional breads. What helps them is their own knowledge and experience, product packaging and information given by the seller. Mostly regional bread is bought at a nearby local grocery store or at the trade fairs and festivals or directly from the manufacturer. When asked to provide three terms associated with traditional bread respondents indicated naturalness, outstanding natural flavour and smell and difficult access to this category of food. The current prices of traditional breads are considered to be too high. According to the surveyed people the variety of types of regional bread is only satisfactory. Better availability, lower prices and easier ways to identify / distinguish traditional products from their conventional equivalents could convince the Malopolska Region residents to more frequent purchases and consumption of regional and traditional breads.

21

The positive attitude of consumers towards regional bakery products should be considered as a factor encouraging a further development of the demand for this category of food. However, this requires a range of actions aimed at i.a. diversification of its sales logistics and creation of a reliable information system about its properties and positive effects on the human body. It can be assumed that in the near future regional bakery products can become a marketing tool to facilitate the promotion of a region. As a typical Polish products they can and should become a showcase to promote our country abroad along with its culinary culture and precious heritage.

ACKNOWLEDGMENTS The study was carried out within the framework of the statutory research of the Food Commodity Science Department of the Cracow University of Economics. Topic 56/KTŻ/1/2012/S/056 "Regional Food. Part II. Regional bread", Cracow, 2012. REFERENCES Biłasiewicz M., 2004, Europa kocha regionalne specjały, Boss-Rolnictwo, 11. Borowska A., 2007, Charakterystyka konsumentów produktów tradycyjnych/regionalnych w Polsce, Raport z badań grant Fundacji „Fundusz Współpracy”. Mat. Konferencji „Rynek tradycyjnej żywności o uznanej jakości”, MRiRW, Program Agro-Smak 2, Ożarów Mazowiecki, 1011.12.2007, 1-17. Boruc M., 2006, Bukiet autentycznej marki, Agro Smak, 3, 6-8. Czarnecka-Skubina E., 2011, Wracajmy do korzeni, Przegląd Gastronomiczny, 9, 8-9. Czerwińska D., 2010, Bez pieczywa ani rusz!, Przegląd Gastronomiczny, 9, 8-9. Gąsiorowski H., 2010, Czy struktura spożycia chleba w Polsce jest dobra i co należałoby zmienić?, Przegląd Zbożowo-Młynarski, 12, 8-12. Giannou V., Kessoglou V., Tzia C., 2003, Quality and safety characteristics of bread made from frozen dough, Trends in Food Science and Technology, 13, 99-108. Guerrero L., Guardia M. D., Xicola J., Verbeke W., Vanhonacker F., Żakowska-Biemans S., Sajdakowska M., Sulmont-Rosse C., Issanchou S, Contel M., Scalvedi L., signe Granli B., Hersleth M., 2009, Consumer-driven definition of traditional foods. A qualitative cross-cultural study, Appetite, 52(2), 345-354. GUS, 2012, Rocznik Statystyczny Rzeczypospolitej Polskiej 2012, Zakład Wydawnictw Statystycznych, Warszawa. Korfel A., 2008, Pieczywo tradycyjne i regionalne na małopolskim stole, Przegląd Piekarski i Cukierniczy, 10, 36-38.

22

Lengard Almli V., Verbeke W., Vanhonacker F., Naes T., Hersleth M., 2011, General image and attribute perception of traditional food, Food Quality and Preference, 22(1), 129-138. Łuczka-Bakuła W., 2004, Produkty regionalne i tradycyjne na rynku europejskim, Przemysł Spożywczy, 4, 36-39. Rothkaehl J., 2012, Jakość pieczywa ma zachęcać do jego spożywania. Ale czy tak jest?, Przegląd Piekarski i Cukierniczy, 12. Sajdakowska M., Żakowska-Biemans S., 2009, Postrzeganie żywności tradycyjnej przez polskich konsumentów na podstawie badań jakościowych, Żywność. Technologia. Jakość, 3(64), 95-104. Slow Food, 2012, Mamy prawo do smaku, Przegląd Piekarski i Cukierniczy, 7, 42-43. Sojkin B., Małecka M., Olejniczak T., Bakalarska M. 2009, Konsument wobec innowacji produktowych na rynku żywności, Wydawnictwo Uniwersytetu Ekonomicznego w Poznaniu, Poznań. Surdel M., Sobczyk A., Kogut B., 2009, Produkty tradycyjne i regionalne w opinii podkarpackich konsumentów, In: Zeszyty Naukowe Południowo-Wschodni Oddz. Polskiego Towarzystwa Inżynierii Ekologicznej z siedzibą w Rzeszowie, Polskie Towarzystwo Gleboznawcze, Oddz. w Rzeszowie”, 11, 253-258. Trichopoulou A., Soukara S., Vasilopoulou E., 2007, Traditional foods: A science and society perspective, Trends in Food Science and Technology, 18(8), 420-727. Vanhonacker F., Verbecke W., Guerrero L., Claret A., Sulmont-Rosse C., Raude J., Signe Granli B., Hersleth M., 2010, How European consumers define the concept of traditional food: Evidence form a survey in six countries, Agribusiness, 26(4), 453-476. Winawer Z., Wujec H., 2010, Tradycyjne i lokalne produkty wysokiej jakości we wspólnej polityce rolnej, Wyd. Fundacja dla Polski, Warszawa. Żakowska-Biemans S., 2012, Żywność tradycyjna z perspektywy konsumentów, Żywność. Nauka. Technologia. Jakość, 3(82), 5-18. Żakowska-Biemans S., Kuc K., 2009, Żywność tradycyjna i regionalna w opinii i zachowaniach polskich konsumentów, Żywność. Nauka. Technologia. Jakość, 3(64), 105- 114.

23

CORRELATIONS BETWEEN SELECTED SHEEP MILK QUALITY PARAMETERS Joanna Ptasińska-Marcinkiewicz Cracow University of Economics, Faculty of Commodity Science, Department of Food Commodity Science, ul. Sienkiewicza 5, 30-033 Cracow, Poland

Abstract: The goal of this research was an analysis of correlations between milk quality parameters such as dry mass, protein, casein, casein number, lactose, fat, ash, acidity, pH, density, viscosity, conductivity, freezing point and color parameters. The experimental material consisted of sheep milk obtained from three breeds: Polish Mountain Sheep, Olkuska sheep and crossbreeds of Polish Mountain Sheep and Friesian sheep (75%x25%). A total of 592 milk samples were obtained during the three years of research. Recorded data were statistically elaborated with Statistica 8.0 PL software. The results of this experiment proved that statisticaly significant correlations between analyzed variables exist. The color parameters correlated significantly with all the other milk qualities, often obtaining the highest values of correlation coefficients. Moreover, the dry matter content significantly correlated with the content of fat, protein, casein, lactose and titratable acidity. The increase in the level of lactose was accompanied by a significant decrease in the amount of fat. The analysis proved also a significant positive correlation between the content of casein and fat, total and soluble ash. The increase in the amount of protein was accompanied by a significant increase in casein content, fat, total and soluble ash and titratable acidity. Interdependence of titratable acidity and pH was negative and statistically significant. There was also significant positive correlation between pH and electrical conductivity. Keywords: sheep milk, quality parameters, correlation, correlation coefficients

INTRODUCTION One of the possible ways to facilitate the analysis of food quality is searching for mathematical models which allow to estimate the content of product‘s components and physical properties that constitute main quality parameters. These models are deliberately simplified description of the relactions existing in the product. The relations are selected depending on the goal of building a model [Gutenbaum 2001]. Milk is a multi-component mixture where three phases can be distinguished: water (molecular), lipid (emulsion) and colloidal. The water phase (proper solution of milk) is formed from lactose and a part of the mineral salts, colloidal part – from casein and certain phosphates, while the emulsion, more particularly the dispersed phase of emulsion constitute 24

fatty components. They are in mutual interdependence, creating a system of physico-chemical equilibrium [Jurczak 2005, Obrusiewicz 1994, Pieczonka 1999]. Some of these interdependencies can be presented numerically or can be described using mathematical models. Most of the equations and models have been developed for cow's milk. Examples include: the Vieth’s formula, the Koestler’s formula, Budsławski formula, Van Slyke’s formula, Richmond’s formula and probably the best known Fleischmann’s formula [Budsławski 1963, 1971, Campbell 1982, Gaweł and Molska 1995, Jurczak 2005, Obrusiewicz 1994, Pijanowski 1980, Ziajka 2008]. The first step to work out mathematical models is the investigation of correlations between given parameters. This experiment was carried out to examine whether or not milk quality parameters correlate and how strongly the pairs of variables are related. MATERIAL AND METHODS The experimental material was sheep milk of three breeds: Polish Mountain Sheep, Olkuska sheep and crossbreeds of Polish Mountain Sheep and Friesian sheep (75%x25%). A total of 592 milk samples were obtained during the three years experiment. Table 1. Characteristics of the sample number of experimental material Year

Number of milk samples

Total

POG*

POG/FRYZ*

OLK*

1

55

16

20

91

2

138

110

63

311

3

76

57

57

190

Total

269

183

140

592

*POG –Polish Mountain Sheep milk, OLK - Olkuska sheep milk, POG/FRYZ - milk of crossbreeds of Polish Mountain Sheep and Friesian sheep Source: own reserch

The samples were taken during the morning milking. A single sample corresponded to the milk gained individually from one sheep. The milking was made manually. During the first months of lactation the milking was made after the separation of lambs lasting about 8 hours. The samples were taken according to procedures and were placed in the glass bottles. The bottles were placed in cooler boxes and immediately transported to the laboratory where the analyses were conducted. The chemical parameters tested comprised determination of: dry matter content according to the oven-drying method [PN-68/A-86122], fat content according to Gerber method [PN-68/A25

86122], casein content according to Wolker method [PN-68/A-86122], lactose content [PN68/A-86122], total ash and ash insoluble in 10% hydrochloric acid [PN-68/A-86122] and proteins content according to Kjeldahl method [PN-EN ISO 8968-1: 2004]. In addition casein number and the soluble ash content (as a difference between total and insoluble ash) were calculated. The physico-chemical parameters of milk covered total (titratable) acidity and pH [PN-68/A-86122], freezing point (temperature) using Funke Gerber cryoscope, density by thermolactodensimeter [PN-68/A-86122], conductivity, viscosity and color parameters. The viscosity was examined on Rheotest RN 3.1 apparatus. The color parameters were determined in the CIE L* a* b* system using the Minolta CM 3500 D. CIE L*a*b* system is the most complete and universally accepted standard for color specification and measurement developed by the International Commision of Illumination. It describes all the colors visible to the human eye. It‘s color scale is based on the opponent-colors theory of color vision, which says that two colors cannot be both green and red at the same time, nor blue and yellow at the same time. As a result, single values can be used to describe the red/green and the yellow/blue attributes. In CIE L*a*b* system, L* defines lightness, a* denotes the red/green value and b* the yellow/blue value. The center L* axis rage from 0 to 100 (0 indicates black or total absorption, 100 - diffuse white). At the center of this plane is neutral or gray. On the a* and b* axis the values runs from left to right, from negative to positive. Positive +a* indicates amount of red while negative –a* of green. Along the b* axis, positive values represent a shift toward yellow, negative toward blue. In both cases 0 means neutral gray [A Guide to… 2007]. The program of the analyses was prepared based on the literature guidelines, European requirements and the Polish Standards. Recorded data were statistically elaborated. The statistical analysis included linear correlation analysis performed to determine the strength and direction of the correlation existing between the measured parameters of milk quality. The value of the linear correlation coefficients were calculated, and then the null hypothesis of the insignificance of the linear correlation coefficient in the general population - "ρ" was verified, i.e., the hypothesis of no significant difference between the absolute value of the ratio and the value 0: H0: ρ = 0; H1: ρ ≠ 0 In other words, the null hypothesis verification will help to assess whether the existing correlation between milk quality parameters in the analyzed sample is only coincidental, or is the regularity in the general population. This verification was performed using Student t test at a given level of significance, α = 0.05 [Dobosz 2001, Stanisz 2000]. The Statistica 8.0 PL 26

software was used for all statistical analyses.

RESULTS AND DISCUSSION The correlations between the variables are presented in matrix form in table 2. Some of the exisiting correlations, even if statistically important (specially those not disscussed below in text), can not be logically explain and are probably random, coincidental. The coexistence of two phenomena may also result from direct impacts on yet another, third phenomenon. On the other side the correlation coefficient close to zero does not always mean lack of dependence, but only the lack of linear relation [Stanisz 2000]. The correlations of the insoluble ash content, therefore of the contaminations contained in the milk, were not analysed as it is very likely they were random. The content of insoluble ash is primarily dependent on human (hygiene). The dry matter content of sheep milk correlated significantly with all components and physical characteristics. The highest correlation coefficients were obtained for the color parameters (for L * r = -0.88, for a * r = 0.86 for b * r = -0.87) and for the content of fat (r = 0.88), total protein (r = 0.70) and casein (r = 0.63). The increase in the dry matter content was accompanied by a statistically significant decrease in the level of lactose. This results form a close relationship between lactose and water in milk. Water content of milk is greatly influenced by lactose synthesis. The process of lactose synthesis is responsible for drawing water into the milk as it is being formed in the mammary gland. This means that the more lactose synthesized, the higher the water content and the lower content of the dry matter [Mustafa]. A significant decrease in the lactose content with the increasing dry matter content was also observed in Rambouillet sheep milk. The resulting correlation coefficient r = -0.47 was similar to that obtained in the discussed experiment [Ochoa-Cordero et al. 2002]. Different result was obtained by Celik et al. [2003] who tested milk of Awassi sheep, for which the correlation coefficient between the dry matter and lactose content was r = 0.87. The increase in the dry matter content was also accompanied by a significant increase in the content of total protein, casein, fat, total and soluble ash as well as in viscosity. At the same time the freezing point decreased significantly. This can be logically explain: firstly, protein, casein, fat and ash are the dry matter components, secondly the more components of dry matter, the less water, and thus the lower freezing temperature and higher viscosity. The results correspond to the research findings concerning Rambouillet ewe’s milk in terms of fat and total protein content. The obtained correlation coefficients were r = 0.96 and r = 0.30, 27

respectively. Whereas changes in the total ash content did not cause significant changes in the dry matter content of Rambouillet sheep milk [Ochoa-Cordero et al. 2002]. Also for the Epirus mountain sheep and Awassi sheep milk high correlation coefficients were obtained for the correlation between the content of dry matter and fat (r = 0.89 and r = 0.92, respectively) and between the content of dry matter and protein (r = 0.45, r = 0.91, respectively) [Celik et al. 2003, Simos et al. 1996 after Ochoa-Cordero et al. 2002]. In addition, a significant positive correlation between the dry matter content and the total ash content was noticed in the milk of Awassi sheep (r = 0.18) [Celik et al. 2003]. The increase in the dry matter content resulted also in the decrease in the casein number, the electrical conductivity and pH and in the increase in titratable acidity (most likely caused by a higher amount of casein – an acidic component of dry matter). Decreasing casein number with increasing amount of the dry matter components suggests that the content of casein in sheep milk increase at lower levels than the content of total protein. It results from the fact that both the increase in casein content and total protein causes increase in the dry matter content, and the casein number is the ratio of casein to total protein. Furthermore, the increase in the dry matter content caused a significant decline in the value of the color parameter L* and b* as well as the increase in the value of the parameter a*. Whereas the density of sheep milk with increasing content of the dry matter was significantly diminished. As logic would seem the increase in density with increasing number of components of milk solids, it can be assumed that the results are random. Another explanation could be a high positive correlation with the fat content, and hence low-density component of milk. The lactose in the sheep milk significantly correlated with the content of total protein, casein, fat and with the casein number, acidity, pH, density, electrical conductivity, freezing temperature and the color parameters. The highest rates were obtained for the fat content (r = -0.66) and for the color parameters (for L* and b* r = 0.55, for a* r = -0.58). A similar coefficient for the correlation between the content of lactose and fat was reported in the paper on Rambouillet sheep milk [Ochoa-Cordero et al. 2002]. Slightly lower correlation coefficient (r = -0.38) was obtained in the research on Merino milk [Bencini and Purvis 1990 after Ochoa-Cordero et al. 2002]

28

0,31*

-0,41* -0,43* -0,88*

0,86*

-0,87*

-0,35* -0,28*

0,17*

-0,66*

0,10

-0,08

-0,32*

0,25*

0,16*

-0,08

0,22*

0,38*

0,55*

-0,58*

0,55*

0,87*

-0,39*

0,62*

0,50*

0,61*

0,53*

-0,07

0,03

0,42*

-0,13* -0,38*

-0,73

0,73*

-0,72*

1,00

0,11

0,55*

0,56*

0,67*

0,48*

0,02

-0,04

0,45*

-0,07

-0,27* -0,67*

0,64*

-0,65*

1,00

-0,22*

0,02

0,01

-0,15*

0,15*

-0,14*

-0,02

0,11

0,26*

0,23*

-0,27*

0,23*

1,00

0,06

0,24*

0,44*

-0,22

-0,27*

0,29*

-0,31* -0,42* -0,83*

0,80*

-0,83*

1,00

0,90*

0,27*

0,32*

0,15*

0,27*

0,43*

0,03

-0,31*

0,26*

-0,29*

1,00

0,31*

0,26*

0,11

0,29*

0,31*

-0,10

-0,45*

0,42*

-0,43*

1,00

-0,63*

0,07

0,21*

-0,31* -0,30* -0,55*

0,53*

-0,52*

1,00

-0,08

0,07

0,52*

0,22*

0,23*

-0,22*

0,21*

1,00

-0,08

0,02

-0,08

0,20*

-0,13*

0,21*

1,00

-0,01

-0,09

-0,34*

0,32*

-0,34*

1,00

0,27*

0,26*

-0,30*

0,26*

1,00

-0,41*

0,40*

-0,41*

1,00

-0,89*

1,00*

1,00

-0,88

1,00

Fat Total ash Soluble ash Titratable acidity pH Density Viscosity Conductivity Frizeeng point L* a*

b*

-0,30* -0,25*

a*

0,57*

L*

0,30*

Frizeeng point

0,15*

Density

0,88*

pH

-0,22*

Titratable acidity

0,63*

Soluble ash

0,70*

Casein number

Conductiv ity

Casein number

Viscosity

Casein

Total ash

Protein

1,00

Fat

Lactose

-0,56*

Casein

Dry matter

Protein

Lactose

Table 2. The interaction of chemical and physical characteristics of sheep milk - the correlation matrix

* Indicates correlations significant at the level of α = 0.05 Source: own research

29

In the analyzed experiment a negative, but statistically insignificant correlation coefficient for the relation between the content of lactose and soluble ash was also received. A similar result was obtained for Rambouillet sheep milk, for which the correlation coefficient was r = 0.13, but it was statistically significant [Ochoa-Cordero et al. 2002]. Such a correlation between the content of lactose and ash, especially the soluble ash is associated with the maintenance of osmotic pressure of milk at a constant level [Kędzior 2005]. Therefore, when the amount of synthesized lactose is reduced, the content of minerals, in particular, the content of chlorine and sodium increase. The increase in the level of lactose in sheep milk was accompanied by a significant decrease in the content of fat, total protein and casein. A significant decrease in the protein content caused by the increasing level of lactose was also observed in Rambouillet sheep milk [Ochoa-Cordero et al. 2002] and Epirus mountain sheep milk [Simos et al. 1996, OchoaCordero et al. 2002]. There was also a significant positive correlation between the level of lactose and the value of the color parameter L* and b*, freezing point, pH, density and a significant negative correlation with acidity and the value of the color parameter a*. Changes of pH and accidity results form the simultaneous decrease of protein and casein – components, which give milk a slightly acidic character. The increase in the content of total protein was accompanied by a significant increase in the content of casein (r = 0.87), fat (r = 0.62), total and soluble ash, as well as a significant increase in acidity, viscosity and the color parameter a*. Whereas the freezing point, the casein number, the electrical conductivity and the value of the color parameters L* and b* significantly reduced. According to the literature [Pijanowski 1980, Ziajka 2008] growth of the protein content, in particular casein, increases the viscosity, while an increase in acidity is associated with a higher content of "acidic" casein. Similarly to this research a significant increase in titratable acidity caused by the increase in the protein content was observed in the milk of Awassi sheep. The obtained correlation coefficient was r = 0.18 [Celik et al. 2003]. A significant increase in the fat content related to increasing amounts of the total protein obtained also Reggio et al. [2007] in the Valle del Belice ewe’s milk, Celik et al. [2003] in the Awassi sheep milk and Ochoa-Cordero et al. [2002] in Rambouillet sheep milk. This correlation can be explain by the fact that fat globules are covered by a thin protein membrane which helps to stabilize the globules in milk emulsion [Mansson 2008]. Ochoa-Cordero et al. have also observed an increase in the total ash content (r = 0.42). Simos et al. [1996 after Ochoa-Cordero et al. 2002] analyzing milk of Epirus mountain sheep also noticed an increase in the fat content with the increasing amount of protein. However, the calculated correlation 30

coefficient between these two variables was much lower (r = 0.26) than in the discussed research. The content of sheep milk casein showed a significant correlation with the majority of the milk components, the physical characteristics and with all of the color parameters. Only in case of the casein number, pH, density and the electrical conductivity correlations were not statistically significant. The highest correlation coefficients were obtained for the relationship with the soluble ash content (r = 0.67) and the color parameters L* (r = -0.67), b* (r = 0.64) and a* (r = -0.65). A strong positive correlation was found between the content of casein and the fat content, total and soluble ash content, acidity, viscosity and the value of the color parameter a*. While a statistically significant negative correlation refered to the relationship between the content of casein and freezing point, the value of the color parameters L* and b*. The increase in the acidity of milk is associated with acidic character of casein caused by its orthophosphate residues [Budsławski 1959, Kędzior 2005]. A positive correlation with total and soluble ash content is probably associated with the composition of casein, which contains inter alia, phosphorus and calcium (the casein micelles are joined by calcium ions, so-called calcium bridges) [Gaucheron 2005, Kukovics and Németh 2013]. The casein number of sheep milk significantly correlated with the fat content, titratable and active acidity, density, the freezing point, and the color parameters. The resulting correlation coefficients were statistically significant, although fluctuated around the value of 0.2. In the remaining cases, insignificant correlation coefficients were close to 0, except for the electrical conductivity (r = 0.11). The increase in the casein number lead to the decrease in density and the color parameter a* as well as to the increase in the freezing point and the color parameters L* and b*. Furthermore, there was a significant negative correlation between the casein number and the amount of fat. Also the titratable acidity and pH decreased as the casein number rose. The fat content in the sheep milk correlated significantly with all the parameters except for the total ash content. The highest correlation coefficients, as in the case of other analyzed milk components, were obtained for the correlations with the color parameters (L* and b*r = -0.83, a* r = 0.80). A statistically significant positive correlations related to the interdependence between the content of fat and soluble ash, acidity and viscosity. Whereas a significant negative correlations were noticed between the content of fat and the freezing temperature. In addition, both the density and electrical conductivity of sheep milk negatively correlated with the amount of fat. This result is consistent with the literature data. According to this data increasing amounts of fat lowers the density of milk [Kędzior 2005]. Unlike in the present 31

work, a negative correlation was obtained for fat and total ash in Rambouillet sheep milk [Ochoa-Cordero et al. 2002]. The change in the total ash content resulted in a significant change in other parameters, except for the freezing point (the correlation coefficients close to 0). A particularly high correlation coefficient was obtained for the correlation between the content of total and soluble ash (r = 0.90). Increase in the total ash amount lead to a significant increase in the value of the color parameter a* as well as to a significant decrease in the value of the color parameter L* and b*. Also the acidity, pH, viscosity, density and the electrical conductivity significantly increased. The increase in conductivity related to the increase in minerals content (the total and soluble ash) is a natural phenomenon as the conductivity largely depends on the concentration of ions in the solution and on their motility [Popek 2001]. In the case of soluble ash content a significant correlation coefficients related to the interdependences with the acidity, pH, viscosity, the electrical conductivity and the color parameters. A higher soluble ash content in sheep milk was accompanied by a significant increase in the value of the color parameter a* as well as a significant decrease in the value of the color parameters L* and b*. Furthermore, in response to the decrease in the insoluble ash content the acidity, pH, viscosity and the electrical conductivity significantly increased. As it was expected titratable acidity and pH reveled a negative correlation, and the resulting correlation coefficient was relatively high, r = - 0.63. The interdependence of titratable acidity and viscosity was positive and was connected with the increase in casein content. The increase in milk acidity caused significant decrease in the conductivity and the freezing point. This result is consistent with previously published data. According to the literature the conversion of lactose to lactic acid - an increase in acidity - lowers the freezing point of milk by 0.01°C for every 1°SH on average [Budsławski 1959]. Furthermore, with the increasing acidity of sheep milk the color parameter a* significantly increased, and the parameters L* and b* significantly decreased. The increase in sheep milk active acidity (pH decrease) was accompanied by a significant increase in the value of the color parameter a* as well as a significant decrease in the value of other color parameters, the freezing point and the electrical conductivity. Density and viscosity of sheep milk did not change significantly. The highest correlation coefficient was obtained for the conductivity, r = 0.52. This correlation is associated with a greater number of ions.

32

In the case of density and viscosity, a statistically significant correlations coefficients were those calculated for the relationship with the color parameters. The increase in density was accompanied by increased values of the color parameter L* and b* and by diminished value of the parameter a*. Whereas in case of viscosity significant positive correlation related to the value of the color parameter a*. In case of remaining color parameters the correlation was significant but negative. Changes in the electrical conductivity and the freezing point related to change in the viscosity were negligible, while the rise of viscosity is expected to lower ion motility and thus decrease the conductivity [Popek 2001]. The increase in the electrical conductivity of sheep milk was accompanied by an increase in the freezing point, the color parameter L* and b* and by a decline in the value of the parameter a*. Although the values of correlation coefficients were relatively low (r ≈ 0.3), they were statistically significant. The freezing temperature of sheep milk significantly correlated with the color parameters. As in the case of viscosity the positive correlation reffered to the value of the parameter a* and negative to the value of remaining color parameters. The value of the color parameter L* changed significantly, in direct proportion to the value of the parameter b* and almost inversely to the value of the parameter a*. Although the correlation coefficient obtained for the relationship between color parameter a* and b* was high, it was not statistically significant.

CONCLUSIONS The results of this experiment demonstrated that a significant correlations between sheep milk physico-chemical characteristics exist. The highest statistically significant correlation coefficients were obtained for the relationship between the color parameters and between the color parameters and sheep milk components (especially the content of dry matter, fat, total protein, casein and lactose). A high correlation coefficients were also obtained for the correlations between a certain components of milk. Surprisingly, the least significant correlations were found for the physical characteristics of milk. The calculated correlation coefficients, even if statistically significant were relatively low. In view of the obtained results, in an attempt to develop mathematical models which allow to estimate the values of sheep milk parameters, one should use the results of the color determination in the CIE L* a* b* system in the first place. This method may be of particular use in estimating the content of fat and protein, as fat, which contain carotenoid pigments, together with protein, calcium and riboflavin contribute to milk's ivory or yellowish color by scattering light at all wavelengths. 33

Additionally analysis itself is very simple, fast and device independent. For this reason it is also worth to consider the development of models based on the relationship between content of casein and dry matter or protein.

ACKNOWLEDGMENTS This work was financed as a research project by the funds for science in the years 2008-2010.

REFERENCES A Guide to Understanding Color Communication, X-Rite, Incorporated 2007 Bencini R., Purvis I., 1990, The yield and composition of milk from Merino sheep, Wool Technol. Sheep Breed, 18, 71-73. Budsławski J., 1963, Chemia i analiza mleka i jego przetworów, PWRiL, Warszawa. Budsławski J., 1959, Mleko spożywcze, Wydawnictwa Przemysłu Lekkiego i Spożywczego, Warszawa. Budsławski J., 1971, Zarys chemii mleka, PWRiL, Warszawa. Campbell J.R., Marshall R.T., 1982, Podstawy produkcji mleka spożywczego i jego przetworów, PWN, Warszawa. Celik S., Ozdemir S., 2003, Chemical composition and major minerals of Awassi sheep milk during lactation, Milchwissenschaft, 7/8, 373-375. Dobosz M., 2001, Wspomagana komputerowo statystyczna analiza wyników badań, Akademicka Oficyna Wydawnicza EXIT, Warszawa. Gaucheron F., 2005, The minerals of milk. Reprododuction Nutrition Development 45(4),473–83. Gaweł J., Molska J., 1995, Analiza techniczna w przetwórstwie mleczarskim, Wydawnictwa Szkolne i Pedagogiczne, Warszawa. Gutenbaum J., 2001, Podstawy modelowania matematycznego, Skrypt WSISiZ, Warszawa. Jurczak M., 2005, Mleko – produkcja, badanie, przerób, Wydawnictwo SGGW, Warszawa. Kędzior W., 2005, Owcze produkty spożywcze, PWE, Warszawa. Kukovics, S. and Németh, T., 2013, Milk major and minor proteins, polymorphisms and non-protein nitrogen, w: Milk and dairy products in human nutrition: production, composition and health (eds Y. W. Park and G. F.W. Haenlein), John Wiley & Sons, Oxford. Mansson H.L., 2008, Fatty acids in bovine milk fat, Food and Nutrition Research, 52. DOI: 10.3402/fnr.v52i0.1821. Mustafa

A.,

An

Overview

of

Milk,

course:

Biology

of

http://animsci.AgrEnv.McGill.CA/courses/460/topics/2/text.pdf, 29.01.2014 Obrusiewicz T., 1994, Mleczarstwo 1, Wydawnictwa Szkolne i Pedagogiczne, Warszawa.

34

Lactation,

Ochoa-Cordero M. A., Torres-Hernandez G., Ochoa-Alfaro A. E., Vega-Roque L., Mandeville P. B., 2002, Milk yield and composition of Rambouillet ewes under intensive management, Small Ruminant Research, 43, 269–274. Pieczonka W., 1999, Towaroznawstwo mleka, Wydział Ekonomii w Rzeszowie, Akademia Rolnicza w Krakowie, Rzeszów. Pijanowski E., 1980, Zarys chemii i technologii mleczarstwa t.1, PWRiL, Warszawa. PN-A-86122:1968 Milk. Test methods. PN-EN ISO 8968-1:2004 Milk. Determination of the nitrogen content Part 1: Kjeldahl method. Popek S., 2001, Studium identyfikacji miodów odmianowych i metodologii oceny właściwości fizykochemicznych determinujących ich jakość, Zeszyty Naukowe Akademii Ekonomicznej w Krakowie, Seria: Monografie, 147. Riggio V., Finocchiaro R., van Kaam J. B. C. H. M., Portolano B., Bovenhuis H., 2007, Genetic parameters for milk somatic cell score and relationships with production traits in primiparous dairy sheep, Journal of Dairy Science, 90, 1998–2003. Simos E. N., Nikolaou E. M., Zoiopoulos P. E., 1996, Yield, composition and certain physicochemical characteristics of milk of the Epirus Mountain sheep breed, Small Ruminant Research, 20, 67-74. Stanisz A., 2000, Podstawy statystyki dla prowadzących badania naukowe. Odcinek 21: Analiza korelacji, Medycyna praktyczna, 10, 176-181. Ziajka S. (red.), 2008, Mleczarstwo 1, Wydawnictwo Uniwersytetu Warmińsko-Mazurskiego w Olsztynie, Olsztyn.

35

QUALITY OF TRADITIONAL AND CONVENTIONAL POLISH HAM Monika Radzymińska, Bożena Garbowska, Dominika Jakubowska University of Warmia and Mazury in Olsztyn, Faculty of Food Sciences,Chair of Commodity Science and Food Research, Pl. Cieszyński 1, 10-945 Olsztyn, Poland

ABSTRACT: This study is a small part of a project aimed at performing comprehensive evaluation of the quality of local raw materials and products in the region of Warmia and Masuria in Poland. This study evaluates selected determinants of the quality of smoked pork hams in relation to origin (small and large scale production). The analytical procedure included examination of selected determinants of the nutritive value (protein and fat content) and the health quality (Σ DDT – dichlorodiphenyltrichloroethane and γ HCH – hexachlorocyclohexane) residues. Moreover, samples from small and large enterprises were subjected to an organoleptic assessment by young consumers (university students). Seven attributes were assessed describing appearance, texture, colour, consistency, smell, taste and overall desirability. Hams produced by small enterprises, from local raw materials and with traditional methods, were found to contain more lipids and significantly less γ HCH as compared to the smoked hams produced by large meat processing companies. Significant differences (P0.05) was recorded, depending on the product’s origin. A significantly higher lipid content was found in traditional ham (16.25±14.47 %), as compared to the local ham (4.38±2.26 %) and the mass-produced ham (9.29±5.25 %).

39

Table 1. Protein and fat content in the ham samples under analysis, depending on its origin (% of product)

Samples origin x 20.06 Local (n=36) Traditional (n=15) 21.26 Conventional (n=36) 19.70 x -mean, SD – standard deviation

Proteins SD 2.56 4.10 4.41

Fat ANOVA F=0.34 p=0.71

x 4.38 16.25 9.29

SD 2.26 14.47 5.25

ANOVA F=4.55 p=0.02

Recommendations for optimal intake of total and unsaturated fatty acids have been proposed by a number of scientific authorities and nutritional organizations including the World Health Organization [WHO 2003, Jiménez-Colmenero et al. 2010]. Depending on the genetic features of a pig breed and differences in feeding systems, hams are characterized by different levels of fat: Iberian hams -19.2% [Jiménez-Colmenero et al. 2009], Parma - 18.4%, or San Danielle hams - 23.0% [D’Evoli et al. 2009]. According to Spanish scientists [JiménezColmenero et al. 2010], fat content is believed to be one of the most crucial quality traits of cured hams (the higher the fat content, the greater the acceptability of cured hams). Fernandez et al. (2007) were assessing the nutritive value of five varieties of Spanish dry cured meat in relation to fatty acid content. Ten hams of the Traditional Speciality Guaranteed (TSG) ‘‘Jamo´n Serrano’’, and the Protected Designations of Origin (PDO) ‘‘Jamo´n de Teruel’’, ‘‘Dehesa de Extremadura’’, ‘‘Jamo´n de Huelva’’ and ‘‘Guijuelo’’, were analysed. The lipid content of the muscle (g/100 g D.M.) ranged from 17.2% in TSG ‘‘Jamo´n Serrano’’ to 29.2% in PDO ‘‘Dehesa de Extremadura’’. Hams belonging to PDO ‘‘Jamo´n de Teruel’’ showed a similar content of intramuscular fat to that observed in PDO “Guijuelo”. Trace levels of Σ DDT and γ HCH residues were found in the analysed samples (Tab. 2). Table 2. Σ DDT, γ HCH content in the ham samples under analysis, depending on its origin (mg/kg of fat) γ HCH Σ DDT Samples Origin SD ANOVA SD ANOVA x x Local (n=36) 0.0003 0.0002 F=3.42 0.0103 0.0155 F=1.71 Traditional (n=15) 0.0002 0.0002 p=0.04 0.0585 0.1251 p=0.19 Conventional (n=36) 0.0008 0.0008 0.0113 0.0101

x -mean, SD – standard deviation

Levels of DDT in the ham samples ranged from 0.0103 to 0.0585 mg/kg of fat and did not differ significantly (p>0.05). On the other hand, the level of γ HCH in the mass-produced ham was statistically significantly higher (0.0008 ± 0.0008 mg/kg of fat) than the levels of those

40

compounds in the local (0.0003 ± 0.0002 mg/kg of fat) and traditional ham (0.0002 ± 0.0002 mg/kg of fat). Chlorinated hydrocarbons, including DDT and its derivatives, are characterised by easiness of accumulation in the food chain [Faruga et al 2008]. The content of chlorinated hydrocarbons in the examined samples of hams was low and did not arouse serious hygienic and toxicological concerns. Other research on organochlorine pesticide residues in meat products and meat of different species showed that in general, lamb meat appeared to be more heavily contaminated with HCB and HCH than other meats. The γ-HCH (lindane) was most frequently detected: 100% in lamb and pork, and 64 to 94% in fresh sausages of poultry and beef [Herrera et al. 1994]. Numerous studies have been conducted with the aim to estimate the toxicity of organochlorine pesticide residues in foods to humans. However, there is no conclusive evidence to corroborate the claim [Beard 2006; Pestana et al. 2010; Parron et al. 2010]. Results of organoleptic assessment (Table 3) showed different levels of organoleptic quality of the hams. Analyses demonstrated a higher quality of traditional samples compared to the conventional products. Total desirability of traditional hams was estimated at the level of 4.66±1.91 and was statistically significantly higher (P