Recovery and techno-functionality of flours and proteins from two edible insect species: Meal worm ( Tenebrio molitor ) and black soldier fly ( Hermetia illucens ) larvae

Abstract

Depending on the species, edible insects are highly nutritious and thus represent a noteworthy alternative food and feed source. The current work investigates the protein extractability and techno-functionality of insect flour fractions recovered from Tenebrio molitor and Hermetia illucens. T. molitor and H. illucens flours contained about 20% crude fat and 60% and 36 % crude protein, respectively. Defatting reduced the crude fat content to 2.8% (T. molitor) and 8.8% (H. illucens) and increased the crude protein content to 68% and 47%, respectively. To isolate proteins from the flours, protein solubility was optimized by varying the pH, the ionic strength, and the extraction temperature of the solvent. All products and by-products accumulated in the protein production process were characterized by composition, selected techno-functional properties, protein solubility, composition and structure as well as their microbial load.

Improvement of techno-functional properties of edible insect protein from migratory locust by enzymatic hydrolysis

“…The isoelectric point (IP) was found to be located at pH 4 (data not shown). These results are in accordance with studies reporting considerable low solubility of insect protein flours derived from mealworm larvae (3-45%; pH 2-9), black soldier fly larvae (10-35%; pH 2-9), house cricket (12-23%, pH 3-9) and tropical banded cricket (5-25%; pH 3-10), especially at weak acidic conditions [20,23,33]. In contrast, Azagoh et al [22] observed higher protein solubility of flour from mealworm larvae between 40-76% from pH 2-10.…”

“…Similar observations of enhanced oil binding properties were reported for globulin-based rapeseed isolate and soy protein isolate after enzymatic hydrolysis [30,51]. The general degree of oil binding found for the hydrolysed and non-hydrolysed MLPF significantly surpasses the OBC of different flours and protein fractions of mealworm and black soldier fly larvae ranging between 0.4 and 0.9 g Oil /g DM [20].…”

“…Flavourzyme and Alcalase) but an increase after proteolysis with Papain. The general extent of water binding was significantly higher in comparison to several flours and protein fractions of mealworm (0.8 g H2O /g DM ) and black soldier fly larvae (0.7 g H2O / g DM ) as reported by Bußler et al [20].…”

“…For mealworm (Tenebrio molitor) and black soldier fly larvae (Hermetia illucens), protein solubilities between 3 and 95% were observed and found to be significantly influenced by the solvent pH, purity of the protein fraction and previous processing [20][21][22]. However, near the isoelectric point (IP) around pH 3 to 7-which reflects the common pH range of many food products-the protein solubility was lowest, especially for non-purified insect flours [20,22,23]. Protein solubility of untreated, defatted and acid-hydrolysed mealworm and silkworm pupae (Bombyx mori) flour were reported to range between 12 and 13% at pH 7.6 [24].…”

Effect of pre-treatment and drying method on physico-chemical properties and dry fractionation behaviour of mealworm larvae (Tenebrio molitor L.)

“…The protein quality in terms of essential amino acid content satisfies the recommendation for adult`s requirement by the WHO [6]. First, studies on techno-functional properties of TML protein fractions revealed promising protein solubilities between 60 and 100% at alkaline pH depending on the applied pre-treatment, extraction procedure and fractions' composition [14][15][16][17].…”