Extraction of dietary fibers from bagasse and date seed, and evaluation of their technological properties and antioxidant and prebiotic activity

Dietary fiber (DF) was extracted from plant byproducts (date seed and sugarcane bagasse) by alkaline hydrogen peroxide extraction and their chemical composition, technological properties, antioxidant activity, and prebiotic activity were evaluated. Bagasse had a significantly higher DF content (48.34%) than date seed (39.89%). Bagasse dietary fiber (BDF) had a significantly higher Fe, K, Mg, Na, and Zn (1343 ppm, 274.69 ppm, 640.08 ppm, 643.08 ppm, and 31.74 ppm, respectively) than date seed dietary fiber (DSDF) with 186.84 ppm, 185.88 ppm, 505.64 ppm, 506.72 ppm, and 13.28 ppm, respectively. The results showed that BDF had significantly higher values for oil binding capacity, water-holding capacity, and swelling capacity which equaled 2.73 g/g, 7.12 ml/g, and 12.50 ml/g, respectively, compared to DSDF (0.81 g/g, 4.06 ml/g, and 8.88 ml/g, respectively). The samples containing 5% DSDF and 5% BDF had the highest stimulating effect on Lactobacillus acidophilus growth, respectively. Also, pH reduction in the studied media depended on the type of DF and its concentration and the trend of decrease in pH was variable. Evaluation of the antioxidant activity of the studied DFs indicated that, at a 500 ppm concentration, DSDF with 89.12% had a significantly higher 1,1-diphenyl-2-picrylhydrazyl (DPPH) inhibition rate than ascorbic acid (85.4%), and with increasing the DF concentration, antioxidant activity increased. The findings confirmed that the studied DFs have prebiotic effects. Due to their technological, physicochemical, and antioxidant properties, they can be used as inexpensive DF sources in the food and pharmaceutical industries.