Effects of industrial by-products from orange, peach palm and soybean on the quality traits and antioxidant activity of flours: a response surface approach

By-products from different sources vary widely in their composition and their functional properties. The aim of this study was to produce industrial by-product flours from orange (OF), soybean (SF) and peach palm (PF), besides formulating and characterizing blends with the use of a simplex-centroid mixture design. The formulation containing 100% PF had the highest ash content (67.9 g.kg-1), while the highest lipid (155.8 g.kg-1) and protein (268.2 g.kg-1) contents were found in the formulation that had 100% SF. Total dietary fiber content of the blends produced ranged from 577.7 to 728.5 g.kg-1. The pH and the water activity varied from 4.1 to 6.7 and from 0.484 to 0.611, respectively, indicating stability and safety for consumption of the formulations. The highest swelling volume (20.8 mL.g-1), water and oil absorption (7.4 and 3.6 g.g-1, respectively) was found for 100% PF, which is important to the industrial applications. The simultaneous optimization showed that 100% OF is the most interesting formulation due to the best balance of insoluble to soluble fiber (2:1) and the highest total phenolic content (4.5 mg gallic acid.g-1) and antioxidant activity. However, the binary and ternary mixtures of by-product flours also had interesting functional properties, and they can be used for the development of healthier foods