Some Antinutritive and Antioxidative Properties of Pulverized Citrus sinensis (Sweet Orange) Peels and Seeds

Introduction: Citrus sinensis (sweet orange) fruit peels and seeds may have antinutriitve and antioxidative properties but are essentially discarded with abundant waste generation.

Aim: This study evaluated some antinutrients and antioxidative property of pulverized Citrus sinensis(sweet orange) peels and seeds, using standard methods.

Place and Duration of Study: The study was conducted at the Department of Biochemistry, Michael Okpara University of Agriculture Umudike, Nigeria between May and August, 2015.

Methodology: The antinutrients were determined by standard methods. The antioxidative property was measured as the 2,2-Diphenyl-1-picryhydrazyl (DPPH) scavenging activity of the respective sample at 100 mg/ml. The potency was measured by estimating the half maximal effective concentration (EC50).

Results: The hydrogen cyanide content in the peels (18.16±0.06 µg/g) was higher (p<0.05) than that in the seeds (11.67±0.07 µg/g) or any other determined antinutrient followed by phenol in the peels (1.06±0.05 mg/100 g) and flavonoid in the seeds (0.69±0.03%). The DPPH radical scavenging activity (percentage inhibition, %) was higher (p<0.05) in the peels (68.58±0.02) than in the seeds (43.73±0.02). Similarly, the EC50(µg/ml) was higher (p<0.05) in the peels (937.40±0.10) than in the seeds (658.60±0.21).

Conclusion: The antinutrient mix in the peels may confer it with higher cyanide toxicity, higher antioxidant activity but lowered antioxidant potency than the seeds. The study seemingly underscores the importance of hydrogen cyanide in the antioxidative activity and potency of the samples. This could be central to other food wastes, warranting further studies aimed at determining and possibly eliminating hydrogen cyanide content of these and other food wastes.