Evaluation of the proximate composition, antioxidant potential, and antimicrobial activity of mango seed kernel extracts

After pulp extraction in fruit processing industry, a significant quantity of mango seed kernels are discarded as solid wastes. These seed kernels can be ideal raw materials for obtaining extracts rich in bioactive compounds with good antioxidant properties. The conversion of these wastes into utilizable food ingredients would help in reducing environmental problems associated with processing waste disposal. In order to determine their potential use, this study evaluated some of the biochemical characteristics and antimicrobial potential of mango seed kernel extracts on medically important human bacterial and fungal pathogens. Four mango varieties (Apple, Ngowe, Kent and Sabine) from Makueni and Embu counties in Kenya were used for this study. The analyzed mango seed kernel powders were found to contain on average, 6.74-9.20% protein content. Apple and Ngowe mango seed kernels had significantly higher fat content of 13.04 and 13.08, respectively, while Sabine from Makueni had the least fat content of 9.84%. The ash, fiber, and carbohydrate contents ranged from 1.78 to 2.87%, 2.64 to 3.71% and 72.86 to 75.92%, respectively. The mean percentage scavenging ability of mango kernel extracts at the concentration of 20 mg/mL was 92.22%. Apple and Sabine mango kernel extracts had significantly high inhibition zones of 1.93 and 1.73 compared to Kent and Ngowe with 1.13 and 1.10, respectively, against E. coli. For C. albicans, the inhibition of Kent mango kernel extract, 1.63, was significantly lower than that of Ngowe, Apple, and Sabine with 2.23, 2.13, and 1.83, respectively. This study demonstrates that mango seed powder is an abundant and cost-effective potential natural antibiotic and antifungal that can be utilized in addressing the challenge of food poisoning and infections caused by pathogenic microorganisms in the food industry.