Effect of Feeding Substrates on the Oil Quality of Rhynchophorus pheonicis and Orycete rhinoceros Larvae.

Abstract

This study evaluated the physicochemical properties of oils extracted from larvae of Rhynchophorus phoenicis and Orycete rhinoceros reared on palm pith (PP) and sawdust (SD) substrates. Four treatment groups were analyzed: Large larvae fed on palm pith (PPLL), large larvae fed on saw dust (SDLL), small larvae fed on saw dust (SDSL), and small larvae fed on palm pith (PPSL). Standard analytical methods were used to determine free fatty acid (FFA), acid value, iodine value, and peroxide value. Results showed significant differences (p < 0.05) among samples for most parameters. FFA values ranged from 1.66 ± 0.075% in PPSL to 6.51 ± 0.077% in SDLL, indicating varying levels of hydrolytic degradation. Acid values ranged between 0.27 ± 0.048 and 1.16 ± 0.009 mg KOH/g, with SDLL recording the highest value. Iodine values ranged from 1.20 ± 0.067 to 3.256 ± 0.049 g I₂/100 g, suggesting low to moderate unsaturation of the oils. Peroxide values varied significantly from 45.00 ± 4.082 to 79.67 ± 0.47 meq/kg, reflecting differences in oxidative stability. Oils from larvae reared on palm pith generally exhibited better quality indices, especially lower FFA and acid values, compared with some sawdust fed samples. The increasing interest in edible insects as sustainable lipid sources has created the need to assess the quality and industrial suitability of insect oils. The findings demonstrate that rearing substrate significantly influences the quality characteristics of insect oils. These oils may have potential applications in food, feed, cosmetics, and biodiesel industries, provided proper refining and storage measures are implemented. The study supports the use of agro waste in insect farming for sustainable lipid production.