Efeito da adição de farinha de cara (Dioscorea alata L.) na qualidade tecnologica da farinha de trigo de alta extração

AUTOR(ES)
DATA DE PUBLICAÇÃO

1979

RESUMO

The importation of wheat to satisfy a continually growing consumption creates an economic burden, not only in Brazil, but in many other developing nations as well. The partial substitution of a locally-produced flour for part of the wheat can help in alleviating such a strain on the national economy. In the present study, the potentiality of the use of the local water yam (Dioscorea alata) as a wheat substitute was examined. The water yam is easily grown in various areas of Brazil with a fairly high yield. Its flour, although basically starchy, is relatively rich in protein (7%). Water yam flour was prepared and added in increasing increments to the most commonly used wheat, flour of 78%, extraction. Its effect on dough rheological properties in the conventional flour-water system (SFA) and in the newly developed flour-water ingredient system (SFAI) was evaluated. Its influence on the bread technological quality was also examined. Water yam flour was found to be fairly resistant to mechanical shear, but quite susceptible to the action of alpha-amylase enzyme at high temperatures of the level generally used in baking. Increasing the percentage of water yam flour in wheat flour increased the water absorption of the mixture; however, the presence of the baking ingredients (yeast, salt, sugar, and fat) inhibited this behavior. The energy required to develop the dough to its optimum structure, as well as its stability, were reduced upon increasing the quantity of water yam flour when tested with SFA. With SFAI the dough development time was much higher than that obtained with SFA, but increasing the yam flour caused a more pronounced drop than with SFA. A reduction in dough extensibility and an increase in its resistance to extension were observed with increasing quantities of yam flour, leading to the conclusion that a dough improving factor exists in water yam flour. With the SFAI the maximum resistance to extension was reduced, while the proportional number remained essentially constant with increasing quantities of the water yam flour, with values much higher than those obtained with SFA; this indicated the vital role of the bread ingredients in increasing the binding forces during the formation of the gluten network. The experimental baking test indicated that up to 16% water yam flour could be added to national wheat flour of 78% extraction without deterioration in quality. The addition of 0.25% ELLC, however, resulted in increasing this limit to 18%. These results were confirmed by pilotpolant scale production of bread using the Chorleywood method. Organoleptic evaluation of French bread made with 18% water yam flour indicated the necessity of accustoming the consumers to this type of bread.

ASSUNTO(S)

trigo farinhas inhame

ACESSO AO ARTIGO

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