Effect of Different Beating and Sterilization Treatments on the Quality of Litchi Pulp

The deterioration of the quality of litchi pulp is closely related to oxygen and heat treatment. This study compared the effects of conventional beating (CB) and low-oxygen beating (LB) on the quality of litchi pulp, and the effect of low-oxygen beating combined with high hydrostatic pressure (HHP) and heat treatment on the quality of litchi pulp during storage at 4 ℃ was also studied. The results showed that when compared to conventional beating, low-oxygen beating had no significant effect on the total soluble solid, pH and total acid of litchi pulp (P>0.05), while the L^* value increased significantly (P<0.05), the a^* value decreased significantly (P<0.05), the total phenolic content increased by 24.70%. Except for proanthocyanidins B2, rutin, catechins and vanillic acid, the content of other 6 monomeric phenolics increased significantly (P<0.05). During the storage process, the L^* value of litchi pulp treatment of different beating methods combined with HPP and HT showed a downward trend and the a^* value showed an upward trend, and the L^* value of LB+HHP group was always the highest. Stored for 28 days, the total phenolic content, DPPH radical scavenging capacity and ferric ion reducing antioxidant power of the low-oxygen beating combined with HHP treatment group were higher than those of the other three groups. In conclusion, low-oxygen beating can better keep the color, phenolics and antioxidant capacity of litchi pulp, and reduce the quality degradation of litchi pulp treated by HHP and heat during the storage, of which LB+HHP treatment has more advantages, which can be used as a new litchi pulp processing technology.