Micronutrient and antinutrient content of semi-processed fruit peels: Towards boosting immunity

Abstract

Background: Fruits are excellent sources of micronutrients; hence, their consumption is highly recommended. However, fruit peels, often discarded, despite some being edible have been reported to contain essential nutrients and antioxidants, which contribute to disease prevention and well-being.

Aim: This study sought to evaluate the micronutrient and antinutrient content of 10 edible fruit peels namely, orange, mango, pineapple, banana, lemon, mandarin, red apple, cucumber, guava and pawpaw peels.

Setting: Laboratory analyses of the fruit peels were conducted at the University of Calabar, in a well-ventilated and temperature controlled environment to ensure accurate results.

Methods: The research design was quantitative and experimental; laboratory analyses were carried out to determine the minerals, vitamins and antinutrients in fruit peels using AOAC standard methods. Data were analysed using ANOVA on SPSS version 20.0.

Results: Calcium was the most predominant of the minerals analysed, with values ranging from 33.12 ± 0.05 mg/100 g (cucumber peels) to 72.04 ± 0.08 mg/100 g (mango peels); calcium was followed by magnesium. Mandarin, banana and pineapple peels had statistically similar (p > 0.05) content of zinc (about 1.2 mg/100g), which was significantly (p < 0.05) higher than others. Mandarin peels had significantly higher content (100.48 ± 2.03 mg/100 g) of vitamin C, while cucumber peels recorded the lowest (27.50 ± 0.01 mg/100 g). The results show significant concentrations of micronutrients such as iron, selenium and vitamin K; among the antinutrients, hydrogen cyanide had the highest concentrations, followed by phytate. The values were within safe limits.

Conclusion: Therefore, the processing of fruit peels, for use as dietary additives to enrich foods and boost immunity, should be promoted.

Contribution: The study shows the potential of fruit peels as food additives.