engleski

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

Methionine, an amino acid containing sulphur, is often limiting factor of nutritive value of proteins in the human diet owing to its low protein amount. Additionally, decline of methionine content occur as a result of its partial destruction during food processing. Since methionine plays an important role in human metabolism and taking into account the fact that its stability can be affected by various factors, the content 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 0.153 g/100g dry matter in biscuit prepared with pure oat fiber and 0.188 g/100g dry matter in biscuit prepared with amaranth flour. After baking, the content of available methionine was lowered 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 uptake for adults, 100 g of examined biscuits could cover up to 47% daily requirements for methionine, thus representing a good source of this essential amino acid.

available methionine; wholegrain cereals; dietetic biscuits

nije evidentirano