engleski

Influence of technological processing on available methionine stability in dietetic tea biscuits

Since, during food processing, the methionine may react with other food components causing a loss of its bioavailability, the impact of technological procedure on stability of available methionine during production (baking) of nine different types of dietetic tea biscuits has been determined. The investigations were carried out on dietetic tea biscuits based on wholegrain wheat flour additionally enriched with different raw materials (oat or barley wholegrain flour, buckwheat flour, amaranth flour or full fat soya flour) or different pure fibers (oat or apple fibers). A biscuit with added sucrose was also prepared to examine influence reducing sugars on methionine stability. The available methionine was determined by the McCarty and Sullivan spectrophotometric method at 513 nm following the papain hydrolysis of the samples. Obtained results of the analysis show that the content of available methionine in examined biscuits varied between 0.134 g/100g dry matter (biscuit prepared with sucrose) and 0.173 g/100g dry matter (biscuit prepared with soya flour). After baking, the content of available methionine was lower in all investigated samples, with the highest reduction in biscuit prepared with sucrose. Greater stability of available methionine could be obtained by utilisation of sugar replacements and artificial sweeteners instead of reducing sugars for biscuits preparation. Taking into account recommended daily intake for adults, 100 g of examined biscuits could cover up to 19% daily requirements for methionine, thus representing a good source of this essential amino acid.

available methionine; wholegrain cereal; dietetic biscuits

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