Effects of Different Physical Field Pretreatment on the Quality of Kiwifruit Jiaosu

In order to explore the effects of different physical field pretreatment on the quality characteristics of kiwifruit Jiaosu, kiwifruit pulp was pretreated with ultrasound (US), pulsed electric field (PEF) and a combination of both (UP), then fermented with Lactobacillus plantarum to produce kiwifruit Jiaosu. The results showed that compared with CK group, the SOD activity in three kinds of physical field treatment groups significantly increased by 27.27%~31.81% (P<0.05), the total acid content increased by 0.77%~2.79%, the DPPH·, OH· and ABTS⁺· scavenging rates increased by 3.17%~4.39%, 0.9%~1.83%, and 1.88%~6.63%, respectively, and the soluble sugar content decreased by 3.23%~10.04%. There was no significant difference in pH and total phenolic content (P>0.05). In addition, the GC-MS results showed that the relative contents of alcohols and ketones in the three physical field treatment groups were higher than those in the CK group by 5.76%~56.75% and 14.71%~32.73%, respectively, and the relative contents of heptanal, trans-2-hexenal, and hexanal were increased. By OPLS-DA analysis, the volatiles in CK, US, PEF and UP groups were distributed in different quadrants. In conclusion, ultrasound, pulsed electric field and their combined pretreatment can all improve the quality of kiwifruit Jiaosu and enrich the volatile substances of kiwifruit Jiaosu, and ultrasound pretreatment is the best.