Temperature-Controlled Mechanical Pressing of Black Soldier Fly Larvae (BSFL): Yields and Qualities of Oil and Protein Meal

Abstract

Black soldier fly larvae (BSFL) decompose numerous organic wastes into valuable oil and protein for promising biofuel, cosmetic, food, and feed applications. In this paper, temperature-controlled mechanical pressing (70°C, 90°C, 110°C, and 130°C) was employed to extract BSFL oil and defatted protein meal simultaneously. A higher pressing temperature of BSFL produced a higher oil yield without a significant impact on the yield of protein meal and material losses. BSFL oil extracted at 110°C showed a good yield (18.83%), fatty acid profile, and saturation level (53.48 g I₂/100 g iodine value and 219.10 mg KOH/g saponification value) similar to palm oil. It exhibited the lowest peroxide value (12.90 mEq/kg) and free fatty acid content (1.14%), with a high carotenoids content (192.60 mg/kg). Due to the potent antioxidant capacity, the accumulation of carotenoids help to maintain the quality and protect the BSFL oil against oxidative attack. As a result, a lower degree of oxidation ultimately reduced the peroxide value and improved the oxidative stability of BSFL oil. Moreover, the high protein dispersibility index (71.25%) of BSFL meal defatted at 110°C also indicated superior quality and bioavailability. Hence, the optimum extraction temperature was found at 110°C, which produced lower oil rancidity, higher stability, and quality of both oil and protein meal for diverse applications.