The effect of Nasunin microcapsules extracted from eggplant peel on physicochemical properties and malondialdehyde content in oily doughnuts

Abstract

Frying serves as a critical process in doughnut production, fundamentally affecting their porous texture, flavor, color, and sensory properties. However, the oil content in the product creates significant challenges, particularly due to the risks associated with oxidation. This research investigates the impact of varying concentrations of Nasunin extract derived from eggplant skin (0.1%, 0.15%, 0.2%, and 0.3%) on the formation of malondialdehyde in doughnuts for 1, 7, and 14 days. Observations indicated that doughnuts prepared with higher concentrations of Nasunin exhibited increased moisture content. Furthermore, the acidity levels of the doughnut samples significantly (p < 0.05) decreased with rising Nasunin concentrations. There was no significant variation (p > 0.05) in the fat content, which ranged from 19.36 to 18.80%. Peroxide values were found to decrease with higher Nasunin levels in the doughnut formulation (p < 0.05). The findings revealed that elevated concentrations of Nasunin caused a significant (p < 0.05) difference in the p-anisidine value and totox index of the doughnut samples in comparison to the control. An inverse linear correlation was observed between Nasunin concentration and malondialdehyde levels. A significant difference (p < 0.05) was noted among treatments concerning color changes, which became more pronounced with higher Nasunin concentrations. During 7 days, no significant variations were detected in the sensory properties (flavor, texture, color, aroma, and acceptability) between the control sample and the one containing 0.2% Nasunin. However, On the 14th day, the sample containing 0.2% Nasunin was found to possess the most enhanced sensory attributes and received the highest acceptability, thus being recognized as the superior sample.