Orange juice has an important role in daily fruit, dietary fiber and nutrients intake as well as in reducing chronical diseases. The attractive orange color is very important feature, therefore browning is unwanted in food industry. Browning can occur even in non-oxidizing medium, where the main browning reactions are Maillard reaction (a reaction between amino groups and reducing sugars) and degradation of ascorbic acid. Products of both reactions are brown pigments. Furthermore, the Maillard reaction and degradation of ascorbic acid can result in loss of nutrients, as well as in the formation of some unwanted compounds. In the thesis we studied the influence of ascorbic acid, dehydroascorbic acid, spermidine and putrescin on color change during incubation at 50 oC. We assumed that each of four compounds will stimulate the browning reaction. We used chroma meter to quantify the change in color during a period of two weeks. The results revealed that only dehydroascorbic acid potentiated unwanted change of color, as larger increase in the parameter a* and larger decrease in L* were found. Bioactive amines putrescine and spermidine and ascorbic acid that are naturally present in the orange juice, decreased the browning rate, as smaller a* and larger L* were determined in comparison with the control at most time points.
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