Effect of kneading and baking on the degradation of the lipid fraction of biscuits

An experimental investigation was carried out with the aim of evaluating the effect of kneading and baking on the degradation of the lipid fraction of biscuits. For this purpose, the raw materials, the dough, and the end-products sampled during processing at a biscuit-making industrial plant were analysed. The results showed that the kneading stage caused a significant decrease in content of polyunsaturated fatty acids and a concomitant significant increase of triacylglycerol oligopolymers and oxidised triacylglycerols that are indexes of oxidative degradation. The subsequent baking step caused the degradation of part of the oxidised compounds to volatile substances, as confirmed by the determination of the p-anisidine value. On the whole, the biscuit-making process, although determining a significant increase of triacylglycerol oligopolymers, has only a small impact on the oxidation level of raw materials.