Modified atmosphere packaging with chitosan coating to prevent deterioration of fresh in-hull Badami’s pistachio fruit

Abstract Background Fresh in-hull pistachio fruits are very perishable and hence have a limited storage life, with marketers and customers wishing for a longer shelf life. The present research was performed to explore the combined effects of different packaging conditions (ambient atmospheric condition, and passive- and active-modified atmosphere packaging) as well as chitosan coating (0, 1, and 1.5%w/v) on postharvest quality of fresh in-hull pistachios stored at 5 °C and 85–90% relative humidity for 45 days. The efficacy of treatments in prolongation of pistachio fruit shelf life was evaluated by determining weight loss, kernel firmness, acid (AV) and peroxide values (PV), mold and yeast count, aflatoxin content, and hull color parameters (L*, a*, b*, C*, h°, and BI) at 0, 15, 30 and 45 days of storage. In addition, O2 and CO2 concentrations in MAP headspace were monitored. Results By applying high molecular weight chitosan coatings and MAP conditions, PV and AV values, microbial growth, aflatoxin B1 production, and weight loss values were inhibited, as well as kernel firmness reduction and hull color deterioration during storage were controlled. Active-MAP treatments in most cases performed better than passive-MAP treatments in this regard (P < 0.05). Combining chitosan coating with MAP demonstrated additive synergistic effects. At the end of storage, 1.5% chitosan-coated treatment under active-MAP maintained firmness (87% of the control treatment), hull lightness (76% of the control treatment), and microbial count (similar to the control treatment). It also maintained minimum weight loss (6.39%), acid (0.91 meq O2 kg−1 oil) and peroxide (0.49 goleic acid/100 goil) values compared to other treatments, proving that chitosan coating combined with MAP was more effective in preserving pistachio quality parameters. The equilibrium O2 and CO2 levels of passive-MAP treatments were maintained at higher values than those of active-MAP treatments which indicated that passive-MAP treatments had higher respiration rates than those of active-MAP treatments during storage. Conclusions The results revealed that applying the combination technique of MAP and chitosan coating effectively preserved the quality attributes and lengthened the shelf life of fresh in-hull pistachios. Therefore, it could potentially be commercialized as a new approach for future industry application. Graphical Abstract