engleski

Tryptophan stability in hard biscuits different raw materials composition

Since the stability of tryptophan during the manufacture and storage of food products depends on a series of factors, the aim of the study was to assess changes in the level of tryptophan according to the composition of raw materials during hard biscuits production. The methodology was based on tryptophan determination in different semi-products - dough and final products - biscuits produced in laboratory conditions. Reference samples were prepared according to the recipes for white wheat flour hard biscuit, whereas in other samples the following were added according to the amount of T-500 flour: whole grain flour, wheat fiber, oat fiber, apple fiber, soya flour, carob flour, inulin or amaranth flour. Tryptophan was determined by the Bates modified method with p-dimethylaminobenzaldehyde after alkaline hydrolysis. The amount of tryptophan in examined samples of dough ranged from 0.052 to 0.122 g/100 g dry matter and from 0.049 to 0.119 g/100 g dry matter in the biscuits. Accordingly, the level of tryptophan decreased during technological procedures from the dough to the final product. The percentage of tryptophan degradation ranged from 2.22 to 11.11 %. The analyses of results show that the damage of tryptophan depends on the types of used raw materials, and that despite the level of tryptophan were significantly reduced in some biscuits, all examined products can still be considered as a good source of this very important amino acid.

tryptophan; stability; biscuit; different raw materials; production

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