Effects of Drying Methods and Blanching on Nutrient Utilization in Black Soldier Fly Larva Meals Based on In Vitro Assays for Pigs

Abstract

The objective was to determine the effects of drying and blanching methods on the nutrient utilization of black soldier fly larva (BSFL; Hermetia illucens) meal by pigs using in vitro assays. Two-step and three-step in vitro assays were employed to simulate the gastrointestinal tract of pigs. Four BSFL meals were prepared using the following pretreatment methods: (1) microwave drying at 80 °C for 32 min, (2) hot-air drying at 60 °C for 17 h, (3) blanching for 5 min in boiling water and hot-air drying at 60 °C for 17 h, and (4) 2% citric acid solution blanching for 5 min in boiling solution and hot-air drying at 60 °C for 17 h. After the drying process, each BSFL was defatted and ground to obtain BSFL meals. The nitrogen (N) concentration in the test ingredients ranged from 8.5 to 9.4%, and the ether extract ranged from 6.9 to 11.5% on an as-is basis. The amino acid (AA) concentration in the BSFL meals ranged from 2.80 to 3.24% for Lys and 0.71 to 0.89% for Met on an as-is basis. Hot-air-dried BSFL meal had a greater in vitro ileal disappearance (IVID) of N compared with microwave-dried BSFL meal (p < 0.05). However, blanched BSFL meals in water or 2% citric acid solution before hot-air drying had a lower (p < 0.05) IVID of N compared with microwave-dried or hot-air-dried BSFL meal. Blanched BSFL meals in water or 2% citric acid solution before hot-air drying showed a lower (p < 0.05) in vitro total tract disappearance of dry matter and organic matter compared with microwave-dried or hot-air-dried BSFL meal. Microwave-dried BSFL meal had a lower (p < 0.05) IVID of indispensable AA, except for His, Lys, Met, and Phe, compared with hot-air-dried BSFL meals. However, blanched BSFL meals in water or 2% citric acid solution before hot-air drying showed a lower (p < 0.05) IVID of indispensable AA compared with microwave-dried or hot-air-dried BSFL meal. In conclusion, hot-air-dried BSFL meal presented greater nutrient utilization compared with microwave-dried BSFL meal for pigs. However, blanching in water or citric acid solution negatively affected the nutrient digestibility of BSFL meal based on in vitro assays.

Mitigation Strategies against Food Safety Contaminant Transmission from Black Soldier Fly Larva Bioconversion

“…For BSF, the process starts with the method of killing, with the exceptions of cases where the live larvae are fed to fish or poultry in the vicinity of the bioconversion facility. Blanching, boiling, toasting, desiccation, freezing, high hydrostatic pressure processing, asphyxiation, and grinding have been tested for their effects on subsequent microbial load, though one must note all can affect the final consistency, digestibility, and nutritional and organoleptic properties of the BSFL product, which are factors producers will have to take into account [ 35 , 98 , 99 , 100 ].…”

“…Post killing, BSFL like any other edible insect can be desiccated with sunlight, hot air, infrared or microwave radiation, freeze-drying, or use of pulsed electric fields; it can also be frozen, pulverized, milled, pressed, fractionated, blanched in water or acid solutions, pasteurized, toasted, smoked, fried, and/or fermented [ 99 , 102 , 112 , 113 , 114 , 115 ]. In addition to reducing microbial contamination, these techniques reduce water content and can improve shelf life and stability [ 116 ].…”

Combined Dietary Supplementation of Tenebrio molitor Larvae and Chitosan in Growing Pigs: A Pilot Study

“…Fishmeal and soybean meal are mainstay conventional protein components in diets for poultry and swine due to their well-balanced and highly digestible content of amino acids, fatty acids, vitamins, and minerals [ 3 ]. However, the constantly increasing production cost of these meals has raised the need for alternative high-protein feedstuffs such as insect meals [ 4 ].…”