Effect of Fig Leaf Extract on Preservation Effect of Different Varieties of Green Walnut

Taking Wen 185, Xinfeng and Xin 2 green walnut as experimental materials, the preservation effect of fig leaf extract on green walnut was studied. The storage condition of walnut was 4 ℃ for 60 days, and the effects of fig leaf extract on the color, weight loss rate, hardness, acid value and soluble protein of walnut kernel during storage were investigated. The results showed that the treatment of fig leaf extract significantly improved the preservation effect of walnut. According to the color and shape of the peel of the green walnut, it could be seen that the green peel of the Xinfeng walnut could be retained well after 60 days of storage, while the green peel of the Xin2 walnut could only be stored for 15 days and the Wen185 walnut could be stored for 45 days. After storage for 60 days, the a^* of Xinfeng walnut peel was −1.21, while that of Xinfeng-CK was 23.87. Compared with the control group, the weight loss rate of Xinfeng, Wen 185 and Xin 2 decreased by 85.28%, 80.39% and 79.41% respectively. It could be seen that the treatment of fig leaf extract delayed the water evaporation rate of walnut and maintained the water content of walnut. The content of malondialdehyde in Xinfeng walnut kernel was the lowest, which was 5.84 μmoL/g, 53.91% lower than that in Xinfeng-CK. Fig leaf extract treatment significantly delayed the accumulation of malondialdehyde in walnut kernel. Xinfeng walnut kernel soluble protein content was the highest 11.38 mg/g, and 55.01 % higher than Xinfeng-CK, it could be seen that the extraction of fig leaves preserved the fresh quality of green walnut, delayed the peroxidation of walnut kernel fat, and improved the preservation effect of green walnut kernel. This study can provide a theoretical basis for the research of preservation technology of green walnut after harvest.