Effect of di-1-p-menthene (pinolene) and sodium alginate biodegradable natural polymers on the quality characteristics and shelf life of fresh pistachios

Abstract

Nowadays, it is essential to find suitable biodegradable/edible films to extend the product's shelf life. This study aims to fill a gap in the existing research on natural coatings by discovering the best amounts of di-1-p-menthene (pinolene) and sodium alginate coatings that can stop mold and yeast growth, slow down weight loss, lower levels of peroxide value and thiobarbituric acid, and keep the food's sensory and visual properties. On the order, the response surface methodology (RSM) was used to find the best coating concentrations that preserve the quality and shelf life of Ohadi pistachios that were kept at room temperature (25 ± 2 °C) for one month. The results showed that linear interaction and square effects were significant on 29 days of storage (p < 0.05). The di-1-p-menthene coating at 0.93% (w/v) and sodium alginate coating at 0.90% (w/v) had optimal desirability of 0.8002. Also, the results demonstrate the predicted moisture loss (5.19%), the growth of mold and yeast (1.84 log cfu/g), and the peroxide value (0.34 meqO₂/kg). The predicted values for thiobarbituric acid, texture, taste, smell, juiciness, appearance, hull, and shell color were 0.077, 11.0, 11.2, 11.1, 11.1, 11.3, and 11.4 (mg/kg), respectively. The highest L∗, a∗, and b∗ indices of hull color were 79.14, 3.66, and 3.66, respectively. Thus, the simultaneous application of di-1-p-menthene and sodium alginate on fresh pistachios showed synergistic effects, shelf-life extension, and preservation of appearance.