Effects of Different Pretreatments on the Quality of Freeze-dried Jujube Slices during Shelf Life

HE Wenhua; HAO Yifan; JIA Chenxia; LI Shenshen; LI Zhigang; SHI Jianchun; WANG Yu; HAO Xiaoling; SHI Yuqin; GAO Lingzhi; SONG Changli

doi:10.13982/j.mfst.1673-9078.2026.1.1466

Abstract：Vacuum freeze-drying effectively preserves the quality of jujube fruit.However,freeze-dried products are prone to quality deterioration,such as color deterioration,during shelf life.To mitigate the quality deterioration of freeze-dried jujube slices during their shelf life,Muzao was selected as the test material and pretreated with various concentrations of citric acid(CA),L-cysteine(L-Cys),and D-sodium erythorbate(D-SE).The sensory and entropy weight TOPSIS methods were used to comprehensively assess and identify high-quality groups by tracking changes in quality indices during shelf life.The results showed that compared with the CK group,1.5%L-Cys and 1.0%CA were more effective in maintaining the quality of freeze-dried jujube slices.L-Cys pretreatment was better than CA pretreatment,with better maintained values of a*(-2.64)and b*(16.07),effective inhibition of PPO activity(6.45 U/g),and slow decrease of chlorophyll(1.39 mg/100 g),carotenoid(0.145 mg/100 g),and total phenol(417.28 mg/100 g)contents in freeze-dried jujube slices over 180 days of shelf life.In contrast,the 0.6%D-SE group demonstrated inferior performance in maintaining the quality of freeze-dried jujube slices during shelf life,with the a* value(-0.79)and PPO activity(14.90 U/g)significantly higher than those of the CK group.These findings suggest that 1.5%L-Cys pretreatment can effectively preserve the quality of freeze-dried jujube slices,delay quality deterioration during shelf life,and extend the shelf life to more than 210 days.These findings provide theoretical support for the high-value processing and utilization of jujube fruit,significantly contributing to the development of the jujube industry.