Optimizing the encapsulation of the refined extract of squash peels for functional food applications: A sustainable approach to reduce food waste.

Abstract

Encapsulation of the refined extract from squash fruit peels was evaluated for the design of functional foods with beneficial effects on human health. The percentage of maltodextrin and gum Arabic in the wall material as well as the concentration of the refined extract were the independent variables for the Box Behnken design, and their impact on response variables (total phenolic compound [TPC] content, DPPH activity, the size of particles, and polydispersity index [Pdi]) was evaluated. The obtained emulsions were compared based on their TPC content, as well as their antioxidant activities. Optimum conditions were as follows: maltodextrin percentage of 23.8%, gum Arabic percentage of 27.7%, and phenolic extract percentage of 48.5%. Under these conditions, the response variables were the following: TPC content of 46.01 mg of gallic acid equivalent per gram of extract (mg GAE/g of E); DPPH inhibition percentage of 64.85% at 1 mg/mL, particle size of 571.22 nm, and Pdi of 0.46. Once the emulsion was optimized, we tried to define the combination of variables that produced microcapsules with the highest TPC content and the highest antioxidant activity. Physicochemical parameters and biological activities were also assessed. Microcapsule parameters were a pH of 4.2, a viscosity of 17 mPa/s, and a turbidity of 0.412 NTU (Nephelometric Turbidity Units), and color measurements were L = 102.4, a = 3.5, and b = 7.8. Indeed, the TPC content was 37.2 mg GAE/g dried residue and antiradical activity against DPPH was 44.2%. The inhibitory effects of the optimized emulsion on Enterococcus faecalis, Pseudomonas aeruginosa, Salmonella typhimurium, and Staphylococcus aureus were investigated, and the results indicated the highest sensitivity (89% inhibition) for S. typhimurium. Our results indicate the efficiency of the optimized emulsification process for developing microcapsules of high quality as well as the potential of using them in the development of novel food and pharmaceutical products.