Effect of Edible Coating Application on the Quality and Bioactive Compounds of Raspberries (Rubus idaeus L.)

Abstract

Raspberries (Rubus idaeus L.) have a limited postharvest shelf life; hence the objective of this work was to study the effect of applying an edible coating based on alginate with or without lemon essential oil on the enzymatic activity (glutathione peroxidase, superoxide dismutase), color, firmness, microbiological quality and antioxidant activity of raspberries. For this, three treatments were elaborated: raspberries without any coating (control treatment, CT), raspberries coating with sodium alginate (2% w/w) (treatment with alginate, TA), and raspberries with sodium alginate (2% w/w) plus lemon essential oil (0.2% w/w) (treatment with alginate and essential oil, TAEO). The results showed that the alginate-based coating was effective in controlling microbial growth during storage, unlike the control, and it also maintained quality parameters (color and firmness) for a longer period during storage (9 days). There was no significant effect from applying essential oil to the alginate-based coating, so it is recommended to analyze other doses. However, an effect when applying alginate-based coating with essential oil was observed on enzymes at the end of storage (p ≤.05) but not on antioxidant capacity. The application of sodium alginate coating (2% w/w) was the best treatment to preserve quality attributes in raspberry; it maintained firmness and color during storage and reduced microbial, thereby prolonging shelf life. It achieved these benefits without negatively altering antioxidant capacity, suggesting a protective effect without causing oxidative stress.