EFFECTS OF 'LAOYABAN' FLAVONOIDS ON FRESHNESS OF 'HONGYAN' STRAWBERRY

Flavonoids were prepared from the leaves of 'LAOYABAN'. The ability of 'Hongyan' strawberry soaked with different flavonoids concentrations of 'LAOYABAN' at 5, 10 and 20 mg/mL for 5 min to affect freshness was determined. Simultaneously, the antimicrobial activity was tested to explore its ability to maintain freshness. The results showed that the flavonoids of 'LAOYABAN' reduced the weight loss rate and decay rate of 'Hongyan' strawberries after harvesting. There was also a reduction in the loss of soluble sugar and vitamin C (Vc) content. In addition, the flavonoids maintained the activity of SOD, reduced the formation of MDA substance, and had a certain antiseptic and fresh maintenance effect on 'Hongyan' strawberry following harvest. When the concentration of flavonoids was 100 mg/mL, the diameter of the inhibitory zone for Escherichia coli, Staphylococcus aureus, Bacillus thuringiensis and strawberry mixed bacteria (isolated from rotten 'Hongyan' strawberries) was 12.4 mm, 11.2 mm, 10.8 mm and 8.3 mm, respectively. The minimum inhibitory concentration (MIC) of flavonoids from 'LAOYABAN' against each of these four bacteria was 6.25, 12.5, 25 and 50 mg/mL, respectively. Therefore, the fresh-keeping effect of 'LAOYABAN' flavonoids on 'Hongyan' strawberry is achieved through their bacteriostatic activity and anti-oxidant activity.