Dietary fiber concentrates of BAU Kul (Ziziphus mauritiana) peel and pulp: processing, modification and utilization as functional ingredients

Abstract

Dietary fiber (DF) is a major health benefit substrate which is mainly found in fruits and vegetables. To get dietary fiber concentrates (DFC) from pulp and peel of BAU Kul, those were pretreated with 96% ethanol and subsequently dried by using an oven dryer at 50 °C for 12 h and a freeze dryer. Then, all the fractions (oven dried pulp fraction, freeze dried pulp fraction, oven dried peel fraction, freeze dried peel fraction ) were analyzed for various physicochemical properties. DF obtained from peel showed significantly better physicochemical, functional, and antioxidant properties compared to DF from pulp, but hydration properties were almost similar between them. The freeze-drying process produced the DF with better physical, functional, chemical, hydration, nutritional, and antioxidant properties than the oven drying process. The high heating temperature and long heating duration in the oven dryer might be responsible for this difference. Freeze dried peel fraction showed the maximum values of DPPH assay (41.39 ± 1.212%), total phenolic content (149.47 ± 2.167 mg GAE/100 g dry matter), and vitamin C (39.5 ± 0.803 mg ascorbic acid/100 g dry matter) compared to other fractions. It had also higher oil holding capacity (2.313 ± 0.03 g oil/g dry matter). Freeze drying process produced DF with higher physicochemical, hydration, and antioxidant properties than oven drying process.