Effect of Chitosan Nanoemulsion on Enhancing the Phytochemical Contents, Health-Promoting Components, and Shelf Life of Raspberry (Rubus sanctus Schreber)

Abstract

Due to high water content and perishability, the raspberry fruit is sensitive to postharvest fungal contamination and postharvest losses. In this study, chitosan was used as an edible coating to increase the storage of raspberries, and nanotechnology was used to increase chitosan efficiency. The fruit was treated with an emulsion containing nanoparticles of chitosan (ECNPC) at 0, 2.5, and 5 g L−1, and stored for 9 d. Decay extension rate, fruit phytochemical contents, including total phenolics, flavonoids, and anthocyanin content, phenylalanine ammonia-lyase (PAL), and guaiacol-peroxidase enzymes and antioxidant activity, and other qualitative properties were evaluated during and at the end of storage. After 9 d of storage, the highest amounts of phenolics compounds, PAL enzyme activity, and antioxidant activity were observed in fruit treated with ECNPC at 5 g L−1. The highest levels of total phenol, PAL enzyme activity, and antioxidant activity were 57.53 g L−1, 118.88 μmol/min trans-cinnamic acid, and 85.16%, respectively. ECNPC can be considered as an effective, safe, and environmentally friendly method for enhancing fruit phytochemical contents, postharvest life, and health-promoting capacity.

Improving the Berry Quality and Antioxidant Potential of Flame Seedless Grapes by Foliar Application of Chitosan–Phenylalanine Nanocomposites (CS–Phe NCs)

“…As seen in Figure 5 b, both concentrations of CS–Phe NCs increased the flavonoid content in both study years. The relevant findings are consistent with Ishkeh et al [ 33 ], who reported that raspberries treated with a chitosan nano-emulsion, especially at 5 g L −1 , exhibited a higher flavonoid content. The higher levels of flavonoids compared to the non-treated groups might be attributed to a reduced conversion of flavonoids to other secondary metabolites or an enhanced oxygen barrier ability playing a significant role in retarding the decline in the flavonoid content [ 44 ].…”

“…Interestingly, this situation resembles the case of salicylic acid-pre-treated pea seeds containing augmented endogenous levels of salicylic acid, which were revealed to be the product of de novo synthesis, not originating from the exogenously given salicylic acid that was taken up and mobilized by the plants [ 42 ]. Similar increases in the production of raspberries treated by chitosan nano-emulsion have been reported [ 33 ].…”

“…Corresponding to their diversity, relevant compounds confer a certain degree of protective roles in response to biotic and abiotic stress factors by acting as non-enzymatic antioxidants [ 39 ]. As reported before [ 33 ], phenolic compounds with their natural fungicide potential might indirectly decrease the decay extension for horticultural crops, in particular. The well-known phenolic compound biosynthesis pathway is based on phenylalanine, tyrosine, and tryptophan amino acids [ 41 ].…”

“…In this study, notable decreases of 56.25% and 47.92% in TA were recorded with 10 mM of CS–Phe NCs compared to the control in 2018 and 2019, respectively. As reported by Ishkeh et al [ 33 ], total acidity is an indicator of the senescence status of fruits and a relevant decline in the TA might be a consequence of higher respiration and ripening rates, which are related to the consumption and conversion of organic acids to sugars during respiration [ 33 ].…”

Effect of Aloysia citrodora Essential Oil on Biochemicals, Antioxidant Characteristics, and Shelf Life of Strawberry Fruit during Storage

“…The applications of artificial antimicrobials for increasing the fruit's shelf life are linked to toxicity effects, which has led to the search for healthier options. Therefore, the recent use of natural sources in fruits to control quality properties is known as one of the more efficient techniques [4,5]. In this regard, the application of essential oils (EOs) could lead to delaying fruit spoilage, maintaining the quality, and increasing the shelf life [6].…”