Farinha de tempeh liofilizado ou torrado na formulação de biscoitos de coco em substituição parcial à farinha de soja: elaboração e caracterização

Abstract

In this study, the benefits and application of tempeh flour as an alternative for soybean flour were evaluated. In the first stage, proximal composition, aglycone and total isoflavone content were analyzed in the soybean and tempeh flour. Grains of cultivars BRS 216, BRS 257 and BRS 267 were tested, in order to verify the effects of Rhizopus oligosporus, which is used for tempeh fermentation, plus the drying methods of controlled toasting and lyophilization, over the final flour. The results for tempeh flour showed an increase in protein content for all the cultivars, especially for BRS 216, which presented final values of 57.36g.100g-1and 59.30g.100g-1 for toasted and lyophilized tempeh flour, respectively. Total carbohidrates presented a reduction for all cultivars, mostly due to water solubilization during the process for tempeh preparation, and the isoflavone content showed a high conversion rate, with gains in aglycone levels (active forms for human consumption) for all lyophilized and toasted tempeh flours. BRS 267 showed the higher values for aglycone, reason to be chosen for the second part of the study, when mixed flour of soybean and lyophilized/toasted tempeh flour were obtained and applied in the formulation of coconut biscuits, which were evaluated for proximal composition, aglycone content, fatty acid profile and affective sensory analyses. Use of tempeh flour caused increase in aglycones level while linolenic acid content remained stable, which is important to reduce risks of coronary diseases. Lipids and protein contents also showed differences, and the sensory analysis demonstrated similarity between the biscuits, with satisfactory scores in aroma, flavor, texture and overall acceptability for cookies containing soy and tempeh flour, when compared to the cookie formulated with soy flour only. Purchase intention was also positive for both, which indicates roasting process, a simple and economically feasible drying method, for processing tempeh to a flour. This ingredient, rich in protein and aglycone isoflavones, important for human health, can be used as a partial substitute for soybean flour in cookies and other bakery products.