Quality characteristics of strawberry fruit following a combined treatment of laser sterilization and guava leaf-based chitosan nanoparticle coating

Abstract

Background Strawberry fruit is a rich source of antioxidants that are beneficial for human health. However, the rapid decline of strawberries dramatically reduces the shelf life and raises postharvest losses. To develop an efficient and ecological approach for maintaining the quality, strawberries (Fragaria x ananassa, cv. Festival) were treated with 0.5% chitosan coating (0.5% Ch), guava leaf-based chitosan nanoparticles coating (Gl-ChNps), and a combination treatment of 1.3 mW/cm2 laser light followed by Gl-ChNps coating (combined treatment), then stored for 12 days at 10 °C and 85–90% RH. The untreated fruit served as a control. Results Semi-spherical particles with an average size of 21.92 nm, a monodisperse nature, and high solution stability were formed. The findings revealed that the combined treatment completely suppressed fungal decay compared to 50% decay in control, and significantly reduced weight loss percentage to 4.68% compared to 27.35% in control. In accordance, the combined treatment had the maximum anthocyanin content and vitamin C, at 42 and 81.1 mg/100 g, respectively. The results showed that treated strawberries had less change in color, total soluble solids, titratable acidity, and pH during storage than untreated strawberries, which exhibited higher chemical changes. Conclusions The edible film of chitosan nanoparticles acted as a semi-permeable barrier that modified and restricted gas exchange, reduced water loss, and delayed fruit senescence. In addition, the combination of laser light with chitosan nanoparticles has been shown to control the pathogens and retain the freshness of strawberries. Graphical Abstract

In situ crosslinked Schiff base biohydrogels containing Carica papaya peel extract: application in the packaging of fresh berries

“…The total soluble solid (TSS) content pertains to the quality evaluation of the sweetness of strawberries. 56 Fig. 7D presents the variations in the TSS content of strawberries during experimental span.…”

Recent Progress in Modified Atmosphere Packaging and Biopolymeric Films and Coatings for Fresh Strawberry Shelf‐Life Extension

“…In fact, pectin degradation has been reported as the major mechanism for softening in strawberry fruit [45]. Enzymes that participate in strawberry softening have been reported to appear only during ripening and include polygalacturonase (PG), pectate lyase (PL), pectin methylesterase (PME), b-galactosidase (b-Gal), a-arabinofuranosidase (AFase), endoglucanase (EGase) and xyloglucan endotransglycosylase/hydrolase (XTH) [46]. As a consequence of the action of these enzymes, strawberry cell walls are disassembled and cell to cell adhesion is reduced, leading to a loss in firmness, which consumers perceive as softening [45].…”

“…Instrumental firmness is defined as the maximum force exerted on strawberry fruit when penetrated or cut under given conditions in terms of deformation rate and distance. Instrumental firmness has been reported to decrease with storage time, with changes as drastic as 71% with respect to original firmness in unpackaged fruit [47]. Since tissue degradation is an enzymatic process, it is affected by temperature and atmospheric gaseous composition; therefore, technologies such as refrigeration and MAP generally tend to mitigate this defect.…”

“…Enzymatic browning is the most relevant process affecting fruit colour, where darkening reactions are catalysed by the polyphenol oxidase (PPO) enzyme and peroxidases [48]. Also, changes in strawberry colour have been related to weight loss, where higher dehydration has been associated with increased PPO activity, anthocyanin degradation and oxidation of soluble phenolic compounds [49], with the consequent fruit surface darkening (decrease in L*), decrease in red colour and decrease colour intensity (decrease in Chroma) [20, 47].…”

“…In packaging experiments, Botrytis or other pathogens, if present, are usually quantified by visual inspection, determining ‘fungal decay’ or ‘decay incidence’ as the number of decayed fruits over the total number of fruits in a package (%) [47, 56]. Strawberry microbiological quality can also be characterized in terms of total aerobic mesophilic counts, yeast and mould counts and coliforms [57, 58].…”