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) degrees C and 90%+/- 5% relative humidity (RH) for 32 d. Sampling was done every 8 d plus 3 d ((20 +/- 2) degrees C and (50%+/- 5%) RH) to simulate retail conditions. Efficacy of medicinal plant extracts in the chitosan matrix varied; lower ethylene production (82.42 mu L C2H4/(kg center dot h)) was seen in fruit coated with Ch+S, and the lowest respiration rate (75 mL CO2/(kg center dot h)) was observed in fruit coated with Ch+B. The control fruit showed the highest ethylene production (84.90 mu L C2H4/(kg center dot h)) and respiration rate (117.98 mL CO2/(kg center dot 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 of passion fruit during storage, and shows potential for commercial applications.

Automated summary

This study found that several medicinal plant extracts combined with chitosan edible coating have different effects on alleviating shrivel and maintaining the quality of passion fruit. Fruit coated with Ch+B performed the best in maintaining fruit quality.