Effects of chitosan coatings fused with medicinal plant extracts on postharvest quality and storage stability of purple passion fruit(Passiflora edulis var.Ester)

Chitosan edible coating(Ch;2%,mass concentration)enriched with 2%of 0.1 mg/L Bidens pilosa(Ch+B),Lippia javanica(Ch+L),Syzygium cordatum(Ch+S),or Ximenia caffra(Ch+X)was applied as a composite edible coating in alleviating shrivel and maintaining the quality of purple passion fruit(Passiflora edulis var.Ester).Treated fruit was dipped for 3 min in the coating solution,and control fruit was dipped in distilled water.The fruit were stored at(8±2)℃and 90%±5%relative humidity(RH)for 32 d.Sampling was done every 8 d plus 3 d(20±2)℃and(50%±5%)RH to simulate retail conditions.Efficacy of medicinal plant extracts in the chitosan matrix varied;lower ethylene production(82.42μL C_(2)H_(4)/(kg·h))was seen in fruit coated with Ch+S,and the lowest respiration rate(75 mL CO_(2)/(kg·h))was observed in fruit coated with Ch+B.The control fruit showed the highest ethylene production(84.90μL C_(2)H_(4)/(kg·h))and respiration rate(117.98 mL CO_(2)/(kg·h)).Fruit coated with Ch+B had the lowest weight loss(41.67%),higher juice content(60.13%)and BrimA(3.31);while the control fruit had the highest weight loss(88.03%),lowest juice content(21.90%),and BrimA(2.49).Shrivel incidence was lowest(23.70%)on fruit coated with Ch+L and highest(83.30%)on the control fruit.Fruit coated with Ch+X had the lowest electrolyte leakage(71.40%),while the control fruit had the highest(91.97%).Fruit coated with chitosan alone performed better than the control fruit but did not exceed the quality of composite chitosan-coated fruit.Based on the principal component analysis,it can be concluded that passion fruit coated with Ch+B was more effective in alleviating shrivel incidence,better maintained the quality ofpassion fruit duringstorage,andshows potential for commercial applications.