Comparative Study Of Bioactive Compounds In The Fresh Strawberry And Dried Strawberry

Strawberry(Fragaria ananassa Duck.)is rich in nutrients,has a variety of bioactive compounds,and has strong antioxidant capacity,which is beneficial to the maintenance of human health and disease prevention.As a major producer and consumer of strawberries,China’s marketed strawberries are mostly fresh fruits,and the proportion of deep processing is extremely low.In order to clarify the effect of different drying methods on the bioactive compounds and antioxidant capacity of fresh and dried fruit in different strawberry varieties,six main strawberry varieties in Shanxi Jinzhong area were used.The extraction process of total phenol in the fresh and dried strawberry was optimized,the antioxidant capacity of fresh fruit of different strawberry varieties was evaluated,and the changes of bioactive compounds of fresh and dried strawberry in each strawberry variety under different drying conditions were compared and analyzed.The main results are as follows:1)Optimization of the extraction process of total phenol of fresh and dried strawberries.Fresh strawberry fruit optimum ultrasonic extraction of total phenol: using 40% methanol as a solvent to feed ratio was 1 g: 18 m L configuration extract at a temperature of 20℃,40 Hz,ultrasonic extraction 30 min.Dried strawberry optimum ultrasonic extraction of total phenol: using 60% ethanol as a solvent to feed ratio was 1 g: 30 m L configuration extract at a temperature of 20℃,40 Hz,ultrasonic extraction 60 min.2)Determination of bioactive compounds in fresh strawberry fruits of different varieties.The total phenol content of the 6 kinds of strawberries ranged from 1.04 mg/g-1.82 mg/g FW,among which the varieties with higher total phenol content were Hongyan and Miaoxiang.The flavonoid content ranged from 0.20 mg/g-0.42 mg/g FW,and the variety with the highest flavonoid content was Miaoxiang.The anthocyanin content ranged from 0.04 mg/g-0.17 mg/g FW.The varieties with higher anthocyanin content were Miaoxiang and Hongyan.The main bioactive substances contained in Miaoxiang and Hongyan were relatively high.3)Determination of antioxidant capacity of fresh strawberry fruits of different varieties.The DPPH·clearance rates of the six strawberry varieties ranged from 43.78%-54.83%.The varieties with the higher DPPH·clearance rate were Hongyan and Xuetu The ABTS·clearance rate ranged from 35.24% to47.93%.The varieties with the higher ABTS · clearance rate were Hongyan and Miaoxiang.The total antioxidant capacity ranged from 2.13 mmol Trolox/g to 2.79 mmol Trolox/g.The varieties with the higher total antioxidant capacity were Miaoxiang and Xiangye.Among them,the total phenol content of strawberry varieties was significantly positively correlated with its antioxidant index ABTS·clearance rate.4)Comparison of changes in biologically active substances of various strawberry varieties under different drying treatments.under freeze-drying treatment,the loss rate of total phenol,flavonoid,and anthocyanin of different varieties of strawberries were lower than that of hot-air drying treatment.Under freeze-drying treatment,the highest loss rate of total phenol content was Xuetu(25.63%),and the lowest was Xiangye(15.80%).The highest loss rate of flavonoid was Fenyu(22.18%),and the lowest was Miaoxiang(13.14%).The highest loss rate of anthocyanin content was Xuetu(50.00%),and the lowest was Fenyu(44.57%).Under hot air drying,the highest loss rate of total phenol content was Miaoxiang(73.98%),and the lowest was Xuetu(60.74%).The highest loss rate of flavonoid was Miaoxiang(87.85%),and the lowest was Xiangye(66.87%).The highest loss rate of anthocyanin content was Miaoxiang(80.91%),and the lowest was Hongyan(74.06%).Therefore,freeze drying is a better drying process.