Optimization of melatonin concentrations and storage time on qualitative properties of Badami pistachio using response surface methodology

Subject Areas : Food Science and Technology

Ali Asadian Ardakani ¹ , Abdolmajid Mirzaalian Dastjerdi ² , Ahmad Shakerardekani ³ , Mansoureh Shamili ⁴

1 - Ph.D. Student, Department of Horticultural Sciences, Faculty of Agriculture and Natural Resources, University of Hormozgan, Bandar Abbas, Iran.
2 - Associated Professor, Department of Horticultural Sciences, Faculty of Agriculture and Natural Resources, University of Hormozgan, Bandar Abbas, Iran.
3 - Associated Professor, Pistachio Research Center, Horticultural Sciences Research Institute, Agricultural Research, Education and Extension Organization (AREEO), Rafsanjan, Iran
4 - Associated Professor, Department of Horticultural Sciences, Faculty of Agriculture and Natural Resources, University of Hormozgan, Bandar Abbas, Iran

Received: 2025-01-15 Accepted : 2025-04-13 Published : 2025-02-18

Keywords: Enzymatic Antioxidants, Melatonin, Pistachio, Response surface methodology,

Abstract :

Fresh pistachios are highly perishable. This study examined the effect of melatonin (0–0.6%) on fresh pistachios (Badami variety) using response surface methodology (RSM) with a central composite design (CCD), followed by storage at room temperature for 40 days. High coefficients of determination, significant p-values, and a non-significant lack of fit for the responses confirmed a good model fit. Results showed that melatonin treatment effectively reduced weight loss and preserved kernel hardness. Antioxidant activity increased with phenolic compound levels, and the interaction between melatonin and storage time had a synergistic effect on antioxidant activity. Although the decay rate increased during storage, melatonin treatment slowed the decay process. Melatonin also increased phenolic content and the activity of antioxidant enzymes (catalase, superoxide dismutase, and ascorbate peroxidase). While peroxide value and microbial contamination increased over time, the increase was less pronounced in treated pistachios (p < 0.05). The control group (melatonin: 0%, time 0–40 days) showed the highest decay, bacterial growth, and peroxide value, along with the lowest antioxidant levels. These findings support the role of melatonin in preserving pistachio quality. The optimal treatment was 0.5% melatonin for 22 days of storage, with a desirability index of 0.57. Model validation was confirmed, as experimental values did not significantly (p > 0.05) differ from predicted values.