Effect of Drying Techniques on Hermetia illucens Prepupae Fatty Acid

Insect meal has been given priority towards achieving sustainable development goals such as a novel food and feed protection, economic stimulus, job creation, the promotion of new scientific development and the mitigation of greenhouse gases by waste recycling. Insect-derived protein sources have become a new, sustainable and novel food for human and animal consumption. The processing and transformation of the original form of the insect and/or insect larvae are required to preserve food and to extend the lifetime of food storage. Hence, the purpose of this study is to investigate the effects of oven and microwave drying on the fatty acid characteristics of Hermetia illucens prepupae. Prior to drying, larvae of Hermetia illucens were grown to the prepupae stage and harvested for further studies. A palm decanter was used as the larvae's substrate. The influence of oven drying time (24 - 72 hours) and temperature (40 - 80ºC) upon fatty acid was investigated, while that of microwave drying power (200 - 250 W) and time (10 - 15 mins) was investigated. An evaluation of the effects of different drying methods on fatty acid chemical properties was conducted, measuring free fatty acids (FFA), acid value (AV) and iodine value (IV). In addition to the biochemical properties of Hermetia illucens prepupae, the compositional fatty acid methyl ester yield (FAME) of Hermetia illucens prepupae was examined for both drying techniques. Microwave-dried materials showed higher values for free fatty acids, acid values, and iodine values than oven-dried products. Following microwave drying, the values obtained for free fatty acids, acid values, and iodine values were respectively 132.44 oleic acid, 263.30 mg KOH/g oil and 46.67 gI/100g. In terms of oven drying, the value attained were 118.34 oleic acid, 232.27 mg KOH/g oil, and 42.54 gI/100g, respectively. Microwave drying of Hermetia illucens prepupae shows higher iodine value due to its higher unsaturated fatty acid content of 37.16 as compared with its oven-dried Hermetia illucens prepupae's which attained at 34.78 of unsaturated fatty acid. For both oven and microwave drying, FAME yields were 90.41 and 94.05, respectively. Lauric acid (C12:00) was the highest compositional FAME at 32.44 and 28.53 for both oven and microwave drying, respectively. An increased level of saturation in FAME is observed in oven drying, which achieved 65.18 compared to microwave drying (62.84). Based on the findings, the choice of various drying techniques can significantly influence the fatty acid characteristics. For instance, higher C12:0 were obtained from oven drying compared to microwave drying. Lauric acid is a potential avian feed addition, improving poultry growth, weight gain, and avian health .The study provides an insight on the suitability of the drying process by taking into consideration the compounds of interest and the potential end-use such as biodiesel and feed production. © 2022 American Institute of Physics Inc.. All rights reserved.