Effects of Various Polymeric Films on the Pericarp Microstructure and Storability of Longan (cv. Shixia) Fruit Treated with Propyl Disulfide Essential Oil from the Neem (Azadirachta indica) Plant

Abstract

Plant extracts represent a rich repository of metabolites with antioxidant and antimicrobial properties. Neem (Azadirachta indica) is a medicinal plant considered the tree of the 21st century. In this study, we investigated the antioxidant and antimicrobial effects of propyl disulfide (PD), a major volatile compound in neem seed, against the pericarp browning (BI), microbial decay incidence (DI), and water loss of longan fruit. Fresh longan cv. Shixia samples were packaged in oriented polypropylene (OPP) and polyethene (PE) packages of different thicknesses (20, 40, and 60 µm). Sterile gauze was fixed inside the packages and 500 uL of PD was placed on them to avoid the direct contact of PD with fruit samples. Packages were sealed immediately to minimize vaporization and stored at 12 ± 1 °C for 18 days. Fruit samples packaged in open net packages served as controls. The results showed that fruit treated with PD in OPP and PE packages significantly prevented losses of water, DI, and BI compared to control treatment. PD also maintained the color, TSS values, TA values, pH values, high peel firmness, high TPC content, and high TFC content, and reduced the activity levels of PPO and POD. Scanning electron microscope (SEM) analysis indicated that the exocarp, mesocarp, and endocarp of longan peel were smooth, uniform, and compact with no free space compared to control, where crakes, a damaged and loose structure, and a lot of fungal mycelia were found. The shortest shelf life of 9 days was observed in control as compared to 18 days in OPP-20 and OPP-40; 15 days in OPP-60, PE-20, and PE-40; and 12 days in PE-60 packaging films. Therefore, PD as a natural antioxidant and antimicrobial agent, in combination with OPP-20 and OPP-40 polymeric films, could successfully be applied commercially to extend the postharvest shelf life of longan.

Total Phenolics and In-vitro Antioxidant Activities in Methanol Extracts of Raw, Ripe and Overripe Neem (Azadirachta indica A. Juss) Seeds

“…bark, leaves, fruits, etc. of A. indica plants are rich in polyphenols and antioxidants which are responsible for many health benefits (Kharwar et al, 2020;Rashmi and Negi 2020;Khan et al, 2022).…”

Antimicrobial and Anti-Inflammatory Activity of Low-Energy Assisted Nanohydrogel of Azadirachta indica Oil

“…It is also considered an antifungal agent and used against a variety of pathogenic fungi, including Alternaria alternate , Fusarium moniliform , Aspergillus niger , Aspergillus flavus , Fusarium oxysporum , Drechslera hawiiness , Fusarium semitectum , Curvularia lunata , Alternaria solani , Sclerotium rolfsii , Penicillium expansum , Alternaria alternate , Monilinia fructicola , A. fumigatus , Trichothecium roseum , and Candida albicans [ 2 ]. The antifungal activity exhibited by Azadirachta indica is attributed to the presence of a volatile compound named propyl disulfide [ 10 ]. The phytocompounds obtained from plants, however, are much prone to oxidation, due to which notable reduction in bioactivity occurred [ 11 ].…”