Mealworm larvae (Tenebrio molitor) and crickets (Acheta domesticus) show high total protein in vitro digestibility and can provide good-to-excellent protein quality as determined by in vitro DIAAS

Abstract

Edible insects, such as mealworms (Tenebrio molitor larvae; TM) and crickets (Acheta domesticus; AD), are a sustainable, protein-dense novel food with a favorable amino acid profile, which might be an alternative to animal proteins. To assess the protein quality of TM and AD, we assessed the digestible indispensable amino acid scores (DIAAS), considering individual amino acids and their ileal amino acid digestibility, using an in vitro model based on the INFOGEST digestion protocol. In addition, we evaluated if various processing and food preparation steps influenced the in vitro digestibility of individual amino acids and the in vitro DIAAS values of TM and AD and compared them to chicken breast as a reference of excellent protein quality. The total protein in vitro digestibility ranged from 91 to 99% for TM and from 79 to 93% for AD and was negatively affected by oven-drying and, to a lesser extent, by chitin-reduction. The in vitro DIAAS values were 113, 89, and 92 for chicken, blanched TM, and blanched AD, respectively, when considering the indispensable amino acid (IAA) requirements of young children between 6 months and 3 years. Across different processing and food preparation methods, the in vitro DIAAS values ranged between 59 and 89 for TM and between 40 and 92 for AD, with the lowest values found in chitin-reduced insects. Due to their similarities to chicken regarding protein composition, total protein in vitro digestibility, and in vitro DIAAS values, TM and AD might be an alternative to traditional animal proteins, provided that suitable processing and food preparation methods are applied. Our in vitro DIAAS results suggest that TM and AD can thus be considered good-quality protein sources for children older than 6 months. The DIAAS calculations are currently based on crude protein (total nitrogen × 6.25), resulting in an overestimation of insect protein content, and leading to an underestimation and potential misclassification of protein quality. The in vitro model applied in this study is a valuable tool for product development to optimize the protein quality of edible insects. Further studies are required to assess the in vivo DIAAS of insects in humans.

Culinary treatments impact the digestibility and protein quality of edible insects: a case study with Tenebrio molitor and Gryllus assimilis

“…Using the calculation based on crude protein (TN × 6.25), it was possible to classify all samples into the category of good protein sources, with T. molitor treated by drying classified as an excellent protein source. In our experiment, the DIAAS of T. molitor ranged from 95.72% to 105.44%, which is consistent with the values reported by Hammer et al ( 35 ), who also determined DIAAS values above 90%.…”

“…Thus, the use of the second calculation method led to an increase in DIAAS’s of approximately 20% for both insect species and all culinary treatments. An increase in DIAAS owing to different calculation methods was also observed in a previous study ( 35 ). However, it should be noted that using the reduced conversion factor of 5.33 for insects as reported by Boulos et al ( 37 ), the obtained DIAAS values ranged from 112.24% to 123.64% for T. molitor and from 95.55% to 103.96% for G. assimilis .…”

“…The overall value, which allows the comparison of individual sources, is related to the amount of the limiting amino acid, that is, the essential amino acid that is least abundant in the protein. From this perspective, DIAAS values can be divided into three categories: 100% or more indicating excellent protein quality, between 75 and 99% indicating good protein quality, and less than 75%, for which it is not possible to make nutritional claims regarding protein quality ( 34 , 35 ).…”

Exploiting Locusta migratoria as a source of bioactive peptides with anti-fibrosis properties using an in silico approach

“…Edible insects have been proposed as an environmentally and economically sustainable source of protein, and are considered as an alternative food, especially to meat. 1 Although their nutrient composition is affected by several factors (e.g., species, sex, developmental stage, habitat, diet, type of processing and preparation), when compared to common meats, edible insects generally contain higher percentages of highly digestible proteins [2][3][4] containing all essential amino acids in adequate proportions for human needs. 1 Insects can be obtained from nature or they can be reared.…”

Innovative Applications of Tenebrio molitor Larvae in the Production of Sustainable Meat Sausages: Quality and Safety Aspects

“…Conventional livestock farming today causes significant ecological damage, such as greenhouse gas emissions, land acidification, soil nitrification and erosion, eutrophication, biodiversity loss, and global freshwater stress [7]. However, reduction in climate change can be achieved not only through the promotion of plant-based food production but more sustainable sources of animal protein, such as the cultivation of the larvae, Tenebrio molitor (Linnaeus, 1758), which exhibit particularly high efficiency [8]. In the future, more food will have to be produced on less land, just as greenhouse gas emissions must be reduced.…”