Studies on the trans-fatty acids and the stability of the fats present in Indian bakery products

Abstract

Fat is one of the most important ingredients in baked products which is highly susceptible to heat and moisture. Therefore, this study has been conducted to assess the thermoxidative changes occurring in the fat as well as the extent to which trans-fatty acids are present. Fats were extracted from products like rusk, white bread, sweet bun, dilkhush, pizza, plain cake, vegetable roll, gluco-biscuits and wafers. These fats and control shortening samples were taken for study. The totox value was found to be high (4.0-30.9) whereas the free fatty acid, peroxide and anisidine values were, 0.31-0.90%, 1.2-11.0 and 11.6-8.9 respectively. Since the products are baked at 180 to 200 °C polar components were determined to be between 3.3 to 5.3% showing a moderate hydrolysis and oxidative changes. Iodine value (51.0 to 73.3) and the Butyro-refractometer reading (42.2 to 55.8) showed moderate unsaturation and all the samples melted below 37 °C. Trans-fatty acid ranged from 35.5 to 46.2% as has also been confirmed by FT-IR. The products selected were considered safe but nutritionally inferior to products prepared with liquid shortenings.