Effect of Two Drying Methods on the Bioactive Cashew Apple Varieties Consumed in the City of Garoua (Northern Cameroon)

Abstract

Aims: The cashew tree (family Anacardiaceae) grows widely in many parts of African countries, including Cameroon. Its fruit and nut are used for food and several studies have shown their beneficial effects on health. This work aimed to evaluate the impact of two drying methods on the content of bioactive compounds and antioxidant activity. Methodology: Four varieties (VAR 1, VAR 2, VAR 3, VAR 4) of cashew apple samples were collected and drying using sun-dried and oven-dried to a constant weight, and then ground in a blender to a powder, the fresh one was cut up and crushed in a blender. All sample were reconstituted with distilled water and polyphenols, flavonoids, alkaloids contents, and antioxidant activity through different mechanisms (DPPH radical, FRAP and TAC assays) were assessed. Results: Alkaloids ranged from 1.50 mg EQui/g MF to 5.69 mg EQui/g DM for fresh and oven-dried VAR 1 respectively, polyphenols ranged from 786.15 mg EAG/g MF to 2836.92 mg EAG/g DM for fresh and oven-dried VAR 1 respectively, flavonoids ranged from 8.18 mg EAG/g MF to 295.45 mg EAG/g DM for fresh and oven-dried VAR 2 respectively. TAC values ranged from 13.09 mg EAA/g MF to 67.06 mg EAA/g for fresh and oven-dried VAR3 and VAR2 respectively. The highest DPPH radical scavenging value (86.25%) was obtained with fresh VAR 4 and the lowest (25.67%) with fresh VAR 1. The highest ferric reducing antioxidant power (FRAP) was obtained with fresh VAR 1 and VAR 3 (0.27 mg AAE/g MF) and the lowest with VAR 3 and VAR 4 oven-dried (0.23 mg AAE/g MF). Conclusion: In conclusion, the different cashew varieties studied in this work are a good source of antioxidants. The drying method significantly affects bioactive compounds and antioxidant activities. A weak but not significant correlation was obtained between the number of bioactive compounds and antioxidant activities.