Effect of glycerol and holy basil essential oil contents on properties of edible films from purple sweet potato flour

Abstract

This research aims to study the content of glycerol and holy basil essential oil on the properties of edible films from purple sweet potato flour. The effect of glycerol content at four concentrations (20, 30, 40 and 50%) was studied. The results showed that all film formulations were able to form a good film. The difference in glycerol content did not show any significant effect on the thickness of films. Moisture content, water activity, water solubility and elongation at break of purple sweet potato flour films increased with the increase of the glycerol content, whereas tensile strength decreased. Studies have shown that the addition of glycerol at the 40% concentration showed good overall properties compared to 20%, 30% and 50% glycerol content. The effect of holy basil essential oil content was studied at three concentrations (0, 0.05 and 0.10%) in combination with the addition of glycerol at a 40% concentration on film properties. The study found that the essential oil content of holy basil had no effect on thickness, opacity and elongation at break of films. While the tensile strength, antioxidant activity and total phenolic content of the films was increased when the holy basil essential oil concentration increased. The film incorporated with 40% glycerol and 0.10% holy basil essential oil showed the highest antioxidant activity content and total phenolic content (1.12 mM Trolox per 100 g of samples and 149.45 mg of GAE per g of samples, respectively). Therefore, the study of edible films made from purple sweet potato flour in combination with holy basil essential oil demonstrate the potential for produce edible films to protect food products and to preserve the quality of food products.