Effects of vacuum frying on the quality of king orange peel in manufacture of chocolate candy fillings

Abstract

Deep-fried orange peel applied vacuum-frying technique to extend its shelf life and to create crispy product that contains natural nutrients, especially looking for marketplace of the product and increasing the value of orange by-products. The effects of vacuum frying conditions on the quality of fried orange peel was evaluated to produce nutritional chocolate candy fillings that has good sensory values. Orange peel slices were fried under vacuum (20 in of Hg) using sunflower frying oil at various temperatures (80°C, 85°C, 90°C, 95°C and 100°C) for different amounts of time (5, 10, 15, 20, 25 and 30 min). After frying, the fried orange peel slices were centrifuged at 140 - 1000 × g for 4 min to remove the frying oil. Results of this study suggest that vacuum frying at 100°C for 30 min showed maximum shrinkage (48%) and 95% of carotenoids were lost. The hardness of fried orange peel increased during the frying process. Sensory evaluation showed maximum acceptability for fried orange peels at 90°C for 25 min. The TBARS indicated a high deterioration in the atmospheric frying oil quality. In contrast, the vacuum frying condition helped preserve the frying oil quality, while the light color of the product was maintained. The results supported the use of the vacuum frying process as a method for frying high quality king orange peel and conserving the quality of oil in the king orange peel.