Alleviative effects of chitooligosaccharides on the quality deterioration of frozen dough subjected to freeze-thaw cycles

Chitooligosaccharides (COS), a group of cationic derivatives, have a number of potential applications in the food industry. However, their alleviative effects on frozen dough products have not previously been well explored. In this work, the effects of adding COS to frozen steamed bread dough later subjected to freeze-thaw (FT) treatment were systematically investigated. The results revealed that COS significantly improved the quality of frozen dough, the specific volume of the steamed bread with the addition of COS increased by 25.4% and the hardness was reduced by 5.9% compared to the control group. In addition, COS also significantly restrained the water migration and retarded the increase in the freezable water content of the dough during FT treatment (P < 0.05). After FT-4, the freezable water content of COS group was decreased by 12.5% in comparison with the control group. In addition, the COS facilitated the prevention of disulfide bond cleavage. The free sulfhydryl content of 4.46 & mu;mol/g in the control group was significantly higher than that of other groups after FT treatment (P < 0.05), which enabled the dough to maintain its rheological properties. Moreover, dough with higher concentrations (0.15% and 0.25%) of COS exhibited better gas-holding capacity. These results revealed that COS can effectively maintain the characteristics of frozen dough, improve the quality of frozen steamed bread, and also provide new insights concerning the cationic polysaccharides used in the preparation of frozen dough.