PRODUCTION AND STORAGE STABILITY OF ANTIOXIDANT FIBER FROM PIGEON PEA (CAJANUS CAJAN) POD

Abstract

Pigeon pea (Cajanus cajan) pods were considered byproducts obtained from food industry which was raw material for the production of antioxidant fiber powder in this investigation. The effects of pretreatment (washing and blanching) and drying temperatures (60, 70, and 80C) on total crude fiber contents, total phenolic concentration and antioxidant activity by the method of DPPH radical scavenging activity and FRAP were evaluated. The results showed that blanched (60C) samples had the shortest drying times of 9.03 h. However, blanching significantly (p≤0.05) reduced antioxidant capacity of dried pigeon pea pod powders when compared to washing with tap water and fresh sample. Higher drying temperature tended to decrease fiber contents and antioxidant activity of dried powder. The pigeon pea pod powders were stored in ziplock bags or vacuum packaging at room temperature for 8 weeks. The moisture content of the powder kept in both packaging increased over time, which correlated with the water activity during 8 weeks of storage. In addition, storage times caused a decline in the levels of total phenolic concentration, DPPH, and FRAP values. The amount of total phenolic concentration, DPPH and FRAP of vacuum-packed samples were significantly higher than those stored in ziplock bags during storage. It could be concluded that washing with tap water and drying temperature of 60C was the most suitable condition for the process of fiber powder with antioxidant activity preparation from pigeon pea pod. Moreover, vacuum packaging method was sufficient to maintain the antioxidant capacity of the sample for 8 weeks.