Modified potato starch and clove essential oil nanoemulsion coatings: a green approach to prevent fungal spoilage and prolong the shelf life of preservative-free sponge cake

In this study, clove essential oil nanoemulsion (CENE) was prepared and used at different levels (0, 1, 3, and 5%) in the formulation of the edible film based on modified potato starch (MPS). Physicochemical (water vapor permeability (WVP), solubility, and color) and structural properties (XRD and SEM) of edible films were studied. According to the results, the prepared CENE had a homogeneous and uniform distribution and its encapsulation efficiency was 80%. The incorporation of CENE decreased WVP, solubility, tensile strength (TS), and lightness (L*) while enhancing elongation at break (EAB) and yellowness (b*) of the films. According to the results, the optimal sample for coating sponge cakes was an edible film solution containing 3% CENE. Its effect on cake was compared to coating without CENE and also uncoated. The coating with 3% CENE maintained the moisture content of the cake, which reduced the firmness process, and weight loss and kept the freshness of the cake during storage. The microbiology analysis results demonstrated the inhibition effect of CENE on the growth of yeast and molds and recorded the lowest load of them compared to the uncoated sample after 21-day storage. According to the sensory evaluation, the overall acceptance score of the coated sample with 3% CENE on the 8th day after baking was acceptable and had no significant difference with the uncoated sample (p > 0.05). In light of this finding, the incorporation of CENE in the MPS edible coating demonstrates significant potential as an effective and safe preservation method for cake.