The Nutritional Quality and Structural Analysis of Black Soldier Fly Larvae Flour before and after Defatting

Abstract

This study aimed to assess the nutritional information and structural overview of the BSFL (black soldier fly larva) flours (full fat and defatted). The BSFL flours were obtained by freeze-drying the larvae and the removal of fat using hexane and isopropanol ratio of 3:2 (v/v), these solvents were used due to their defatting efficiency and because they are less toxic. Nutritional and structural analyses were conducted using standard methods. The full-fat and defatted flours had high protein content (45.82% and 56.11% respectively). Defatting significantly (p < 0.05) increases the protein content by approximately 10%, while the fat content decreased from 25.78% in full-fat larvae to 4.8% in defatted larvae. The compositional data were qualitatively confirmed with Universal Attenuated Total Reflectance Fourier Transform Infrared spectroscopy (UATR-FTIR) mainly in the amide I and II regions. Thermal gravimetry (TG) and differential scanning calorimeter (DSC) analysis, showed the conformational physical changes induced due to removal of fat which affected protein denaturation. DSC analysis displayed curves of both endothermic and exothermic reactions. During the first heating program, both samples had wide endothermic heating peaks ranging from 42 to 112 °C, which may be attributed to the water content in the samples evaporating. The first stage of the decomposition process was important, with loss of free and loosely bound water up to 150 °C, according to TGA curves. Protein and carbohydrates volatilized during the second stage of decomposition. The third level may be linked to polypeptide decomposition. FTIR revealed that the defatting process induced structural modifications on the amide I (1650 cm−1) and amide II (1540 cm−1) regions. Defatting has a significant effect on the functional groups and nutritional value of the BSFL. Defatted as well as full-fat flour both show good nutritional and structural characteristics for use in many food applications, however the improved proximate composition of the defatted BSFL can be applied to food products using BSFL flour as an alternative ingredient.

Proximate and fatty acid analysis of Black Soldier Fly Larvae (Hermetia illucens)

“…Another parameter which was fairly high in BSF larvae was ash content, which indicated the presence of inorganic (mineral) content in BSF larvae. BSF larvae contain several minerals, such as calcium, iron, magnesium, manganese, potassium, sodium, and zinc [16].…”

Development of semi-artificial feed in the larva stage of the black soldier fly Hermetia illucens (Diptera: Stratiomyidae)

“…After treatment, testing the nutritional status of H. illucens was done by analyzing the water, fat, and protein content contained in the larvae. The test method used in analyzing the moisture content by the oven (thermogravimetry), fat content using the micro-Soxhlet method (Zozo et al 2022), and protein content using the Kjeldahl method (Maehre et al 2018).…”

“…Analysis of the fat content profile was aimed at the essential fatty acid profile, especially the content of linoleic acid, which is important for the physiological process and the creation of linolenic acid (Adamkova et al 2017). The procedure of analyzing fat content, according to Zozo et al (2022), is as follows: i) 5 g homogenized sample was weighed and wrapped using filter paper, placed in a Soxhlet extraction device mounted above the condenser, and a fat flask below; ii) hexane solvent is used, and reflux is carried out until the solvent drops into the fat flask. Next, the solvent in the fat flask is distilled and collected; iii) the fat flask containing the extracted fat was then dried in an oven at 105℃ for 5 hours; iv) the fat flask is then cooled in a desiccator for 20 minutes and weighed; v) the percentage of fat content can be calculated using the following formula.…”

“…The procedure evaluates the total Nitrogen (N) concentration, converted to a protein conversion factor (Levi and Jean 2017). The procedures for analyzing protein levels, according to Zozo et al (2022), i) a 5 g sample is weighed, mashed, and put in a 30 mL Kjeldahl flask, added HgO concentrated; ii) destruction was carried out until a clear green color; iii) adding 60 mL of water and 50% NaOH solution before being transferred to a distillation flask; iv) distillate is accommodated in an Erlenmeyer flask which has previously been filled with 0.1 N and red metal indicator and then distilled accommodated; v) contents of the Erlenmeyer flask are titrated with 0.1 N NaOH until the yellow color is obtained; vi) the protein content is calculated based on the N content in the material by multiplying the conversion factor. The formula for calculating protein content is as follows.…”

Source variation in nutrient profile and the effects of Black soldier fly (Hermetia illucens) larva meal at graded levels in diet on performance, carcass traits, serum biochemical profile and cellular immune response in broiler chicken

“…The average apparent ileal digestibility coefficient of amino acids also is moderate (0.68, Marco et al 2015) to very high (0.85-0.95, Matin et al 2021;0.84-0.91, Mahmoud et al 2023) in BSF larva meal (BSFLM). The larvae are also rich in calcium and phosphorous, besides other minerals such as potassium, iron, manganese, zinc and copper (Zulkifli et al 2022;Zozo et al 2022). Despite these good attributes, the exoskeleton of BSF larvae contains chitin, a constituent of cell wall, which may inhibit nutrient utilization in animals.…”