Kernel Properties and Pasta-Making Quality of Five European Spelt Wheat (Triticum spelta L.) Cultivars E. Marconi,1,2 M. Carcea,3 M. Graziano,1 and R. Cubadda1 ABSTRACT

Cereal Chem. 76(1):25-29

The kernel characteristics and composition, milling performance, protein quality, and alveograph parameters of five spelt cultivars grown in European countries were determined in relation of their utilization in pasta products. Long pasta was manufactured and chemically characterized, and its quality was assessed by sensory and chemical tests. Protein and fat contents were high in the grains (15.7 and 4.4% db, mean value, respectively). Total fiber varied from 10.5 to 14.9% db. The average β-glucan content was 1.2% db. The milling performance as deter-

mined by yield, damaged starch, ash, and particle-size distribution in the flour was uniform among the five cultivars. The results of the SDS sedimentation and gluten index tests indicated that spelt gluten strength was low, and this was confirmed by the alveograph test. Sensory and chemical evaluations of the pastas, however, indicated that spelt is suitable for obtaining good-quality pasta. The combination of the high protein content and the high-temperature drying cycle adopted in pasta production could be responsible for these good results.

The increasing popularity of hulled wheats (spelt, emmer, and einkorn) as environmentally friendly cereal crops for production of niche cereal-based products is stimulating research into their utilization in traditional and new nutritious, attractive foods such as breakfast cereals and extruded cooked products. Pasta is a traditional cereal-based food that is becoming increasingly popular worldwide because of its convenience, nutritional qualities, and palatability (Cubadda 1994). In Italy and throughout the Mediterranean region in general, durum wheat is the cereal of choice for pasta production. However, flours from other cereals or pseudocereals such as barley and buckwheat are successfully used in several countries (Nagao 1995, Jadhav et al 1998). Within the frame of a European research project aimed at finding new ways of exploiting underutilized cereals, this study was undertaken to widen the present knowledge of kernel characteristics of European spelt cultivars in connection with their pasta-making potential. At present, there are limited and incomplete data on the ability of spelt to produce alimentary pasta of suitable quality (Cubadda and Marconi 1996). However, the finding that dry pasta is industrially produced from farro (Italian for hulled wheats) and durum wheat blends and is successfully marketed in Italy is encouraging (D’Antuono and Bravi 1996). In addition, Ranhotra et al (1995) reported that pasta from spelt is being produced and marketed in Michigan and Ohio in the United States. This article describes some of the physicochemical and functional properties of five European spelt cultivars and experiments aimed at assessing the quality of pasta made from these cultivars.

The samples were dehulled by passing them twice between rubbercoated rolls and removing the hulls by aspiration.

MATERIALS AND METHODS Materials Grains of five spelt wheat (Triticum spelta L.) cultivars, Ebners Rotkorn, Rouquin, Triventina, Balmegg, and Oberkulmer were obtained from stocks grown in Austria, Belgium, Italy, and Switzerland. Ebners Rotkorn was obtained from Bundesamt unt Forschungszentrum fur Landwirtschaft, Institut fur Pflanzenbau, Vienna, Austria (M. Werteker); Rouquin from Station d’Amelioration des Plantes, Gembloux, Belgium (A. Dekeyser); Triventina from Istituto del Germoplasma, Bari, Italy (P. Perrino and G. Laghetti); and Balmegg and Oberkulmer from Federal Research Station for Agroecology and Agriculture, Zurich, Switzerland (M. Messmer and S. Zanetti). 1 DISTAAM,

Università del Molise, Via De Sanctis, 86100 Campobasso, Italy. author. Phone: +39 874 404616. Fax: + 39 874 404652. E-mail: [email protected] 3 Istituto Nazionale della Nutrizione, Via Ardeatina 546, 00178 Roma, Italy. 2 Corresponding

Publication no. C-1999-0104-07R. © 1999 American Association of Cereal Chemists, Inc.

Physical, Milling, and Pasta-Making Tests Test weight was determined by a Schopper chondrometer equipped with a 250-mL cylinder. The 1,000 kernel weight was obtained by weighing sets of 250 kernels randomly chosen after removal of broken grains. Kernel hardness (hardness index) was measured with the SKCS apparatus (Perten Instruments, Huddinge, Sweden) that automatically separates kernels and determines individual kernel weights, diameters, and crushing force profiles. The hardness index is then calculated from ≈300 valid measurements by using a hardness algorithm. Whole-meal flour was obtained by grinding the grain in a laboratory mill (0.5-mm sieve) (Cyclotec 1093, Tecator, Hoganas, Sweden) and, for wet gluten and gluten index, in another laboratory mill (0.8-mm sieve) (model 3100, Falling Number, Huddinge, Sweden). Flour was obtained from each cultivar by tempering the grains for 18–24 hr to 15.0% moisture and milling them in an experimental mill (model MLU 202, Bühler, Uzwill, Switzerland) equipped with three break and three reduction rolls and six steel screens. Flour particle-size distribution was determined with a sifter (Bühler) by using 100 g of flour and a 5-min sifting time. Five sieves, 20 cm in diameter, with mesh sizes of 363, 183, 130, 85, and 65 µm were used. These flours were used for manufacturing long pasta (spaghetti) by means of an experimental pasta-making apparatus (Pavan, Padova, Italy) composed of a press and a dryer. A commercial durum wheat semolina was also used for manufacturing a comparison pasta. Flours were mixed for 15 min with tap water (40°C) to obtain a dough suitable for extrusion (volume of water added was ≈33% of flour weight). Extrusion occurred at 40 ± 5°C and a pressure of 60 ± 10 atm (1 atm = 101.29 kPa). All spaghetti was dried according to a 7-hr drying cycle during which the relative humidity was lowered in a linear gradient from 90% rh at the beginning to 70% rh at the end. The drying temperature was a 50-min linear gradient from 25 to 90°C followed by 10 min at 90°C and 160 min at 85°C and ending with a 200-min linear gradient from 85 to 40°C. The diameter of the dried spaghetti was 1.65–1.70 mm. Analytical Tests Whole-meal flour, flour, and pasta samples were analyzed by standard procedures (ICC 1995) for moisture (Method 110/1), crude protein (N × 5.7) (Method 105/2), total fat (Method 136), and ash (Method 104/1). Soluble, insoluble, and total dietary fibers were quantified by the enzymatic gravimetric procedure of Prosky, Method 985.29 (AOAC 1995). Digestible carbohydrates were calculated by difference. β-Glucans were determined according to Vol. 76, No. 1, 1999

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good quality, and 40 to ≤50 was not completely satisfactory; >50 to ≤70 was fair; >70 to 80 was good; and >80 was excellent. Total organic matter (TOM), the amount of surface material released from cooked pasta into the washing water after exhaustive rinsing, was determined by the standard chemical method of D’Egidio et al (Method 153, ICC 1995). TOM values >2.1 g/100 g corresponded to low quality, between 2.1 and 1.4 g/100 g predicted

RESULTS AND DISCUSSION The proximate chemical composition of whole meal from the five spelt cultivars examined is shown in Table I. Proteins ranged from a minimum of 14.3% db in Ebners Rotkorn to a maximum of 18.4% db in Triventina. These values can be considered high compared with the average protein content of European bread and durum wheat cultivars (Mattern 1991) and are in agreement with results found by other authors (Ranhotra et al 1996b, Piergiovanni et al 1996, Grela 1996). However, protein content can be significantly affected by location and agronomic technique (Ranhotra et al 1996b). In fact, Grela (1996) and Ranhotra et al (1996a) found in the whole meal of the same cultivar (Rouquin) protein contents of 10.1 and 14.6% db (N × 5.7), respectively. The high fat content of the spelt samples (mean = 4.4% db) was similar to that found by Grela (1996) in four spelt cultivars grown in Poland, in which crude fat averaged 3.8% db. Lower values (approximately 2.5% db) were also found by Abdel-Aal et al (1995), Ranhotra et al (1995), and Piergiovanni et al (1996), but they were still significantly higher than those of common wheats. These findings could suggest that the germ was present in higher proportions in the kernels of spelt than in those of common wheats. However, Ranhotra et al (1996b) reported fat levels lower in spelt than in common wheats. Total fiber content varied from 10.5% db (Ebners Rotkorn) to 14.9% db (Triventina). These values are in agreement with data obtained by Ranhotra et al (1996a, b). However, from a nutritional point of view, it is important to differentiate between soluble and

TABLE I Proximate Composition of Whole Meal of Spelt Cultivars (% db) a

Cultivar Ebners Rotkorn Rouquin Triventina Balmegg Oberkulmer Mean Coefficient of variation a b

Protein (N × 5.7)

Fat

Ash

14.3d 14.7c 18.4a 15.6b 15.7b 15.7 10.2

3.9d 3.8d 5.2a 4.4c 4.9b 4.4 13.8

1.95b 2.10a 2.05a 1.59d 1.80c 1.90 11.1

Digestible Carbohydratesb 69.4 66.7 59.5 64.6 66.2 65.2 5.8

Dietary Fiber Insoluble

Soluble

Total

β-Glucans

8.7c 10.2b 12.9a 12.6a 9.0c 10.7 18.4

1.8b 2.5a 2.0a 1.2c 2.4a 2.0 26.3

10.5e 12.7c 14.9a 13.8b 11.4d 12.7 13.9

1.18b 1.04bc 0.92c 1.40a 1.27ab 1.16 16.4

Means in a column followed by the same letter are not significantly different at P ≤ 0.05. By difference. TABLE II Kernel Characteristics and Milling Performance of Spelt Cultivarsa

Cultivar Ebners Rotkorn Rouquin Triventina Balmegg Oberkulmer Mean Coefficient of variation a

Test Weight (kg/hL) 75.3b 72.6d 75.0b 78.7a 74.5c 75.2 2.9

1,000 Kernel Wt Kernel (g) Hardness 54.2b 49.3c 38.9e 47.0d 55.8a 49.0 13.7

31.1b 27.6b 21.6d 36.1a 28.7b 29.0 18.2

Flour Yield (%)

Ash in Flour (% db)

Damaged Starch (% db)

70.6 70.0 71.0 70.3 68.7 70.1 1.3

0.55b 0.52b 0.63a 0.48c 0.54b 0.54 11.1

3.01ab 2.22c 2.45c 2.86b 3.31a 2.77 15.9

Means in a column followed by the same letter are not significantly different at P ≤ 0.05.

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CEREAL CHEMISTRY

Flour Particle Size (µm) (%) >183 23.1 16.3 9.8 19.2 18.6 17.4 28.1

>130 to 85 to 65 to 50–70 = fair; >70–80 = good; >80 = excellent. Grams per 100 g of dry pasta. >2.1 = low quality; ≥1.4 to ≤2.1 = good quality; and 2.5 g/100 g of dry pasta) (unpublished data). Therefore, pasta was manufactured according to a high-temperature drying process, as previously specified. Composition, appearance, and cooking quality of pasta produced with spelt flours and with commercial durum wheat semolina (used for comparison) are reported in Table IV. Except for the obvious higher protein content (14.6% wb) of the Triventina pasta, the protein contents of the samples were similar. However, it is worth noting that all the spelt pastas had protein contents significantly higher than that of durum wheat. Fat contents of Ebners Rotkorn, Rouquin, and Oberkulmer were similar to that of the durum wheat pasta (≈1.7% wb). Pasta from the other two cultivars, particularly Triventina, had fat contents almost double (3.2% wb) that of durum because of the lipids present in the whole-meal spelt flour. In all of the spelt cultivars, the ash content, ranging from 0.43 to 0.60% wb, was well below that of the standard durum wheat pasta (0.81% wb). Dietary fiber values were comparable to those of commercial durum wheat pasta. Color measurements indicated spelt pastas were darker (lower L* values) and less yellow (lower b* values) than the durum wheat pastas. However, Triventina was distinguished by a darker, amberreddish shade. The sensory evaluation of cooked pasta (Table IV) showed that stickiness ranged from high (Rouquin) to absent (Triventina), bulkiness was rare except for Triventina (almost absent), and firmness was sufficient for all cultivars except Triventina, where it was very good. Accordingly, the lowest total score (52) was awarded to Rouquin and the highest (93) to Triventina. These values corresponded to a range spanning from fair to excellent quality (Cubadda 1988). It is also interesting to note that most spelt cultivars (Ebners Rotkorn, Rouquin, Balmegg, and Oberkulmer) were awarded scores below that of the durum wheat pasta, which scored 86 with a protein content of 10.7% wb. However, Triventina, with a protein content 14.6% wb, achieved the highest score (93) and was judged very favorably. These results were confirmed by TOM values. Triventina had the lowest value (1.1 g/100 g of dry pasta), whereas the other spelt pastas ranged from 1.6 to 2.0 g/100 g of dry pasta. CONCLUSIONS It is well established that pasta cooking quality is dependent on both protein quantity and quality. The spelt cultivars examined had high protein contents but lacked protein quality. This negative factor, however, did not seem to adversely influence the resultant pasta quality. The explanation for this lies in the fact that the two factors, quantity and quality, can act separately depending on the drying technology adopted (i.e., low- or high-temperature drying). Different temperatures modify components and influence cooking quality in different ways. At low temperatures (40–50°C), the variables mentioned are equally important in determining the final 28

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pasta results, whereas at high temperatures (≥80°C), protein quantity is more important and is strongly correlated with the resultant pasta quality (D’Egidio et al 1990, Novaro et al 1993, Cubadda 1996). This is a consequence of the fact that high temperatures applied at an early stage of the drying process produce a strong protein network capable of preventing starch granules from escaping from pasta during cooking (Resmini and Pagani 1983, Cubadda and Acquistucci 1987). In this study, spelt flours with high protein contents were used and pasta was manufactured according to the high-temperature cycle most commonly used by industrial pasta manufacturers. This combination of conditions resulted in the production of good-quality pastas from spelt wheats. Other experiments with samples possessing different properties are needed to assess spelt performance under a number of conditions. ACKNOWLEDGMENTS This work has been financially supported by the European Community (EC) within the frame of the FAIR European Programme: Project “Spelt, A Recovered Crop for the Future of Sustainable Agriculture in Europe,” EC Contract FAIR CT 96-1569. We thank L. Bartoli, E. Caproni, and J. Krizanovic for technical assistance and La Molisana Industrie Alimentari, Campobasso, Italy (F. Sorrentino and G. Bosco), for the color measurements of pasta samples. LITERATURE CITED Abdel-Aal, E.-S. M., Hucl, P., and Sosulski, F. W. 1995. Compositional and nutritional characteristics of spring einkorn and spelt wheats. Cereal Chem. 72:621-624. Abdel-Aal, E.-S. M., Hucl, P., Sosulski, F. W., and Bhirud, P. R. 1997. Kernel, milling and baking properties of spring-type spelt and einkorn wheats. J. Cereal Sci. 26:363-370. American Association of Cereal Chemists. 1995. Approved Methods of the AACC, 9th ed. Method 14-22, approved October 1976, reviewed October 1994; Method 32-23, approved November 1995, reviewed October 1996; Method 38-12, approved November 1995; Method 76-31, approved January 1995. The Association: St. Paul, MN. AOAC. 1995. Official Methods of Analysis of the Association of Official Analytical Chemists. 16th ed. Method 985.29. The Association: Arlington, VA. Cubadda, R. 1988. Evaluation of durum wheat, semolina, and pasta in Europe. Pages 217-228 in: Durum Wheat: Chemistry and Technology. G. Fabriani and C. Lintas, eds. Am. Assoc. Cereal Chem.: St. Paul, MN. Cubadda, R. 1994. Nutritional value of pasta. Effects of processing conditions. Ital. Food Beverage Technol. 3:27-33. Cubadda, R. 1996. Pasta quality: The relationship between raw material properties and production technologies. Pages 164-168 in: Proc. World Pasta Congr., 1st. Chiriotti Editori: Pinerolo, Italy. Cubadda, R., and Acquistucci, R. 1987. Pasta and extrusion cooked foods from unconventional raw materials. Pages 319-326 in: Food Science and Technology, Trends in Food Processing. I. H. G. Ang, ed. Academic Press: New York. Cubadda, R., and Marconi, E. 1996. Technological and nutritional aspects in emmer and spelt. Pages 203-212 in: Hulled Wheats. Proc. Int. Workshop Hulled Wheats, 1st. S. Padulosi, K. Hammer, and J. Heller, eds. IPGRI: Rome. D’Antuono, L. F., and Bravi, R. 1996. The hulled wheats industry: Present developments and impact on genetic resources conservation. Pages 221-233 in: Hulled Wheats. Proc. Int. Workshop Hulled Wheats, 1st. S. Padulosi, K. Hammer, and J. Heller, eds. IPGRI: Rome. D’Egidio, M. G., and Nardi, S. 1996. Textural measurement of cooked spaghetti. Pages 133-156 in: Pasta and Noodle Technology. J. E. Kruger, R. B. Matsuo, and J. W. Dick, eds. Am. Assoc. Cereal Chem: St. Paul, MN. D’Egidio, M. G., Mariani, B. M., Nardi, S., Novaro, P., and Cubadda, R. 1990. Chemical and technological variables and their relationships: A predictive equation for pasta cooking quality. Cereal Chem. 67:275-281. Grela, E. R. 1996. Nutrient composition and content of antinutritional factors in spelt (Triticum spelta L.) cultivars. J. Sci. Food Agric. 71:399-404. Halverson, J., and Zeleny, L. 1988. Criteria of wheat quality. Pages 15-45 in: Wheat: Chemistry and Technology, Vol. 1. Y. Pomeranz, ed. Am. Assoc. Cereal Chem.: St. Paul, MN. ICC. 1995. Standard Methods of the International Association for Cereal

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Novaro, P., D’Egidio, M. G., Mariani, B. M., and Nardi, S. 1993. Combined effect of protein content and high-temperature drying systems on pasta cooking quality. Cereal Chem. 70:716-719. Pasqui, L. A., and Carcea, M. 1996. Technological and quality characteristics of Italian wheat. Molini Ital. 47(11):19-24. Piergiovanni, A. R., Laghetti, G., and Perrino, P. 1996. Characteristics of meal from hulled wheats (Triticum dicoccon Schrank and T. spelta L.): An evaluation of selected accessions. Cereal Chem. 73:732-735. Ranhotra, G. S., Gelroth, J. A., Glaser, B. K., and Lorenz, K. J. 1995. Baking and nutritional qualities of a spelt wheat sample. Lebensm.-Wiss. Technol. 28:118-122. Ranhotra, G. S., Gelroth, J. A., Glaser, B. K., and Lorenz, K. J. 1996a. Nutrient composition of spelt wheat. J. Food Compos. Anal. 9:81-84. Ranhotra, G. S., Gelroth, J. A., Glaser, B. K., and Stallknecht, G. F. 1996b. Nutritional profile of three spelt wheat cultivars grown at five different locations. Cereal Chem. 73:533-535. Resmini, P., and Pagani, M. A. 1983. Ultrastructure studies of pasta. A review. Food Microstruct. 2:1-12. Wood, P. J., Braaten, J. T., Scott, F. W., Riedel, K. D., Wolynetz, M. S., and Collins, M. W. 1994. Effect of dose and modification of viscous properties of oat gum on plasma glucose and insulin following an oral glucose load. Br. J. Nutr. 72:731-743.

[Received April 21, 1998. Accepted September 24, 1998.]

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