Induction of Carrot Ice Structural Protein and Its Effect on Starch Gel Freeze-Thaw Stability

In this study,carrot was used as raw material for cold induction treatment and ice-binding phosphoric acid buffer solution was used to extract carrot ice structural proteins(Carrot ice structuring proteins,CISPs). In order to investigate the influence of CISPs on freeze-thawed starch gel,CISPs were added to wheat gelatin starch. The results showed that both carrot protein and CISPs increased regularly with the decrease of temperature and the extension of induction time. CISPs content reached 0.758 mg/L at -4℃,which was 89.03% higher than that before induction. At 11 d and 7 d of cold induction,the content of both was the highest,reaching 1.7 mg/L and 0.936 mg/L,respectively,which increased by 100% and 114.7% compared with that before induction. It indicated that low temperature and cold induction for a certain period of time promote the production of carrot protein and CISPs. CISPs was composed of 8 protein components by the confirmation of SDS-PAGE:133.633, 95.570, 82.092,67.950,58.053,47.578,36.518 and 16.164 kDa. With the addition of CISPs,the gel hydration rate of wheat starch after 5 freezing-thawing cycles decreased by 14.38%,the elasticity and cohesion increased by 35.71% and 86%,and the hardness,adhesiveness and masticability decreased by 52%,9.43% and 19.51%,compared with the control group. The best effect was achieved when the amount of CISPs was 1.5%. It indicates that ISPs has a good antifreeze protection effect on the freezing-thawing stability of starch gel.