Rapid population growth is leading to an increase in the demand for high-quality protein such as fish, which has led to a large increase in aquaculture. However, fish feed is dependent on fishmeal. It is necessary to explore more sustainable protein alternatives that can meet the needs of fish. Insects, due to their high protein content and good amino acid profiles, could be a successful alternative to fishmeal and soybean meal traditionally used in sectors such as aquaculture. In this work, seven species of insects (Hermetia illucens, Tenebrio molitor, Acheta domestica, Alphitobius diaperinus, Gryllodes sigillatus, Gryllus assimilis, and Musca domestica) approved by the European Union (UE) for use as feed for farmed animals (aquaculture, poultry, and pigs) were studied. Their proximate composition, hydrolysis of organic matter (OMd), hydrolysis of crude protein (CPd), degree of hydrolysis (DH/NH₂ and DH/100 g DM), and total hydrolysis (TH) were analyzed. The results showed that Tenebrio molitor had digestibility similar to that of fishmeal, while Acheta domestica and Hermetia illucens provided similar digestibility to that of soybean meal. The acid detergent fiber (ADF) data were negatively correlated with all protein digestibility variables. The differences in the degree of hydrolysis (DH) results and the similarity in total hydrolysis (TH) results could indicate the slowing effects of ADF on protein digestibility. Further in vivo studies are needed.

In recent years, the potential of insects as a sustainable protein alternative to feed the growing world population has been explored. Differences in the ways insects are processed can affect their proximate composition and digestibility. This work studied the effects of the combination of different types of slaughter methods and drying temperatures on the proximate composition, organic matter digestibility (OMd), hydrolysis degree (DH/NH₂ and DH/100 g DM), total hydrolysis (TH), and hygienic and sanitary characteristics of BSFL (black soldier fly larvae) meal. Four types of slaughter methods were used including freezing (F), blanching + freezing (B), Melacide^® + freezing (M), and liquid nitrogen slaughter (N). Each of these was used with three drying temperatures (50, 70, and 90 °C). A negative correlation between the acid detergent fiber (ADF) and protein digestibility parameters was obtained. The most suitable drying temperature was 70 °C, as it produced higher values of protein digestibility (DH and TH), resulting in hygienic and sanitary conditions suitable for food use. Slaughtering with liquid nitrogen and blanching was more conducive to achieving high protein digestibility results than traditional freezing or the use of Melacide^®.

Insects are an emerging protein alternative in aquaculture. To obtain an easy-to-handle feed with an improved nutritional quality, longer shelf life and better hygienic-sanitary properties, the insects must go through a multi-step process including sacrifice, drying and defatting. This work aims to evaluate the effect of the interaction of different successive methods of processing of Hermetia illucens larvae proximate composition, digestibility, and microbial loading. The examined methods were slaughtering (blanching or freezing), drying (oven drying or freeze drying) and defatting (mechanical press or supercritical CO ₂ extraction). Our results showed that the combination of freeze-drying and mechanical press defatting resulted in the highest residual fat content ( ), that could negatively affect the relative protein content of the meals. Despite this, with respect to in vitro amino acid digestibility, the least favorable results were obtained from the samples dried by lyophilization and defatted by supercritical CO ₂ extraction ( ), independently of the slaughter method. Regarding the oxidative status, the slaughter by freezing conserved a higher level of antioxidant defenses versus the blanching method ( ), although only the freeze drying method ensured a lower level of lipid oxidation in this type of sacrificing method. The applied processes resulted in a decrease in the presence of pathogenic bacteria compared to the raw insect in all examined groups. The mesophilic aerobic microorganism content was heavily affected by the temperature applied ( ), while the enterobacteria were also affected by the lyophilization, in addition to temperature. Salmonella spp was eliminated from all meals, except for the combination of freezing (sacrifice), freeze drying (drying) and supercritical CO ₂ extraction (defatting). Sulfite-reducing clostridia were not present in any of the prepared insect meals.

In recent years, the potential of insects has been explored as a sustainable protein alternative to sustain the growing world population. Differences in the way insects are processed can affect their proximate composition and digestibility. This work studies the effects of the combination of different types of slaughter methods and drying temperatures on the proximate composition, organic matter digestibility (OMd), hydrolysis degree (DH/NH2 and DH/100 g DM), total hydrolysis (TH) and hygienic sanitary study of BSFL (black soldier fly larvae). Four types of slaughter methods were used: frozen (F), blanched + frozen (B), Melacide® + frozen (M) and liquid nitrogen (N), each with three drying temperatures (50, 70 and 90 °C). A negative correlation between acid detergent fibre (ADF) and protein digestibility parameters was obtained. 70 °C was the most suitable drying temperature, as it reported higher values of protein digestibility (DH, TH), resulting in hygienic and sanitary conditions suitable for food use. Slaughtering with liquid nitrogen and blanching were more convenient than traditional freezing or the use of Melacide® to achieve higher protein digestibility results.

The nutritional composition of insect-derived meals is strongly influenced by insect diet, while defatting can further modulate nutritional quality. However, some defatting methods, such as supercritical CO₂ extraction, depend on sample properties, including density and macromolecule distribution. Therefore, diet-induced changes may affect lipid extraction efficiency and kinetics, a relationship that remains unexplored. This study evaluated the impact of feeding Hermetia illucens larvae with by-products from olive oil industry (olive leaves, OL, at 15, 30 or 50%; dry full-fat olive pomace, OP, at 30, 50, 70, 90%) or quinoa processing (husk, QH, at 15, 30 or 50%) on supercritical CO₂ defatting performance, meal composition, amino acid profile and digestibility. Despite diet-induced variations in lipid accumulation, defatted kinetics mainly depended on the content and solubility of extractable material, while differences in packed bed microstructure had a minor effect. Protein-rich meals were obtained (25–35%), although most diets reduced protein content, except OP50. QH15 and OP30 worsened essential amino acids in meals, whereas OP50 improved them. Chitin content increased, especially for OP-based meals. Digestibility slightly improved with OP30, OP70, QH15, and QH50. These results show the potential of olive oil and quinoa by-products to be up-cycled by H. illucens into high-value insect meals, without compromising the processing by supercritical CO₂ defatting, supporting sustainable insect-based food and feed production.