Agronomia Costarricense 10 (1/2): 43-49. 1986.

EFECTO DE LA COCCION Y LA PRESENCIA DE CASCARA SOBRE EL VALOR NUTRITIVO DE LA MALANGA (Colocasia esculenta) EN DIETAS PARA RATAS 1/*

Emilio Vargas** Lisbeth L. Mata*** AdrianaBlanco**** ABSTRACT Effect of heat treatment on the nutritive valueof taro (Colocasioesculenta) with or without peel on laboratory rats. A study with ratswasconductedto evaluatethe effect of different cooking times with the presenceor abscenseof peelson the nutritional value of taro (Colocasiaesculenta).Two types of meals were prepared, one with and the other without peels.Cero, ten and twenty minute cooking times at 98 C were usedfor the peel and non peel meals.All sampleswere assayedfor protein quality in diets madeup of 81%of taro 11.5% soybeanmeal, 5% soybeanoil, 1% cod liver oil and 1.5% of a vitamin and mineral mixture. A dry milk diet wasusedasthe control. Eight weanlingrats of the Sprague-Dawlystrain were usedper experimentalgroup and placedin individual all wire screencagesand fed ad-libitum, with water availableall the time. Weightgainsand feed intake were measuredat the beginingand at the end of the experiment.The NPR assaylastedthe conventionall0- day period. A significant difference (P < 0.05) was observedon the growth of the rats fed the cooked taro either with or without peels.Weightgainswere 13.6,28.6 and 34.1 gl10 days for the raw, 10 and 20 minutes cooked taro skinlesstreatments, respectively.The presenceof peels affected the performanceof the animals, speciallywith the raw taro treatments.Net protein ratio observedwas 2.5, 2.7 and 4.8 for the treatmentscontainingtaro with peels,without the peelsandthe control diet, respectively.The results suggestthat taro contains a toxic or antinutritional substance that is destroyedby heat exposureat 10 and 20 minutes under 98 C temperature.The information obtained also showedthat the toxic compoundsarein higherlevelsin the skin. -'

1/

Recibidoparapublicaci6n el 31 dejulio de 1985.

INTRODUCCION

*

Trabaj?realizado c°l1.1° partedel~onvenio deco~ per~~ion entre-el Instituto