Functional properties and essential amino acid composition of proteins extracted from black soldier fly larvae reared on canteen leftovers

This study investigated the functional properties and essential amino acid composition of proteins extracted from black soldier fly larvae which represent a good source of proteins (30.12% dry matter). The proteins extracted in alkaline conditions (pH 11) were then isolated using two different recovery methods, (i) ultrafiltration, and (ii) isoelectric precipitation. Ultrafiltration provided higher purity of proteins (96.42%) but a lower extraction yield (24.30%) compared to isoelectric precipitation which provided a protein purity of 76.02% and higher extraction yield (37.22%). All essential amino acids were present in adequate quantities for human requirements. The fraction of proteins obtained by ultrafiltration had significantly higher oil holding capacity and foaming capacity than isoelectrically precipitated proteins. The protein fractions obtained by ultrafiltration and isoelectric precipitation had oil holding capacity of 125.8% and 81.6%, while the foaming capacity was 141.9% and 114.3%, respectively. These technological functionalities can be used to improve human food characteristics, thus resulting in enhanced consumer acceptance

Host plants preferred by tuta absoluta (Meyrick, 1917) larvae for pupation

Tuta absoluta also known as the leafminer of tomatoes is an invasive pest able to destroy an entire field or greenhouse with tomato plants in a few days. With this study we intend to prove the preference of larvae for pupation. For the study we have used leaves from five plant species: tomato, eggplant, pepper, fig, and Solanum nigrum. Three randomly chosen types of leaves were placed in Petri dish. The most prevalent preference of larvae was for the tomato leaves, followed by Solanum nigrum while the eggplant showed little attraction for the larvae and pepper leaves were untouched. From this study we can conclude that tomato leaves were the most preferred by T. absoluta larvae for their pupation

Effect of Rearing Temperature on Growth and Microbiota Composition of Hermetia illucens

The potential utilization of black soldier fly (Hermetia illucens) as food or feed is interesting due to the nutritive value and the sustainability of the rearing process. In the present study, larvae and prepupae of H. illucens were reared at 20, 27, and 33 °C, to determine whether temperature affects the whole insect microbiota, described using microbiological risk assessment techniques and 16S rRNA gene survey. The larvae efficiently grew across the tested temperatures. Higher temperatures promoted faster larval development and greater final biomass but also higher mortality. Viable Enterobacteriaceae, Bacillus cereus, Campylobacter, Clostridium perfringens, coagulase-positive staphylococci, Listeriaceae, and Salmonella were detected in prepupae. Campylobacter and Listeriaceae counts got higher with the increasing temperature. Based on 16S rRNA gene analysis, the microbiota of larvae was dominated by Providencia (>60%) and other Proteobateria (mainly Klebsiella) and evolved to a more complex composition in prepupae, with a bloom of Actinobacteria, Bacteroidetes, and Bacilli, while Providencia was still present as the main component. Prepupae largely shared the microbiota with the frass where it was reared, except for few lowly represented taxa. The rearing temperature was negatively associated with the amount of Providencia, and positively associated with a variety of other genera, such as Alcaligenes, Pseudogracilibacillus, Bacillus, Proteus, Enterococcus, Pediococcus, Bordetella, Pseudomonas, and Kerstersia. With respect to the microbiological risk assessment, attention should be paid to abundant genera, such as Bacillus, Myroides, Proteus, Providencia, and Morganella, which encompass species described as opportunistic pathogens, bearing drug resistances or causing severe morbidity

Lipid profile and growth of black soldier flies (Hermetia illucens, Stratiomyidae) reared on by‐products from different food chains

BACKGROUND The total amount of bio‐waste produced annually in the EU by the food and beverage chains is estimated at 37 Mtons. The possibility to use insects for the valorization of by‐products from these value chains may represent a sustainable solution. This study aims at investigating the by‐products obtained from different food chains for the rearing of black soldier fly prepupae to evaluate lipid content and profile and outline its possible applications. The substrates used in this experiment were: (i) industrial by‐products (brewery spent grains, cow's milk whey, grape stalks, and tomato peels and seeds) and (ii) by‐products from retailers (bread dough, fish scraps, and spent coffee ground). Fat extracted from prepupae using an adjusted Folch method was utilized for total lipid content and fatty acids profile. RESULTS Best larval performances were obtained from beer (0.22 gweight per prepupa), tomato (0.19 gweight per prepupa), and cheese (0.14 gweight per prepupa) food‐chain by‐products. The extremely different composition of the substrate was reflected in the differentiated lipid profile of black soldier fly prepupae and in a range of ratios between unsaturated and saturated fatty acids comprised from 0.37 for cow's milk way to 1.34 for tomato peels and seeds. CONCLUSION The high content and type of lipids, together with the proteins, and chitin extracted from prepupae are high‐value bio‐based products that could be used in the feed/food industry or for the development of innovative biomaterials, such as biodiesel. These results suggest that food chain by‐products are the best candidate for insect‐bioconversion purposes

Antimicrobial Biomasses from Lactic Acid Fermentation of Black Soldier Fly Prepupae and Related By-Products

Worldwide, thousands of insect species are consumed as food or are used as feed ingredients. Hermetia illucens, ‘black soldier fly’, is one of them, and a large amount of puparia and dead adults flies are accumulated during rearing. These materials represent important wastes but no studies are still present in the literature regarding their functional properties and potential reuse. Lactic acid bacteria (LAB) are a heterogeneous group of bacteria contributing to various industrial applications, ranging from food fermentation, chemicals production to pharmaceuticals manufacturing. A LAB feature of industrial interest is their ability to produce antimicrobial metabolites. Considering the scientific and commercial interest in discovering novel antimicrobials, this work will be direct towards fermentation of insect-derived biomasses: puparia and adults insect at the end of life cycle. To the best of our knowledge, the in vitro antimicrobial activity of fermented insects is tested for the first time. This study aimed also to evaluate differences in the composition between fermented and unfermented insects, and to study whether the fermentation and the type of LAB used played a crucial role in modifying the composition of the substrate. Results firstly highlighted fermentability of this species of insects, showed that fermented black soldier flies puparium possess a high antimicrobial activity against tested pathogens. Moreover, result of chemical composition showed that fermented biomass had a higher percentage of fat and a more complex fatty acids profile

Pilot scale production of Hermetia illucens (L.) larvae and frass using former foodstuffs

The food and feed sector requires new sustainable sources of protein and innovative solutions for upcycling of food waste (former foodstuffs), which today is downcycled into energy or even wasted. This study aimed at evaluating the use of former foodstuff waste streams as feed substrate for Hermetia illucens (L.) larvae (black soldier fly larvae, BSFL) under long-term and semi-industrial conditions. Different foodstuff-based mixtures and different stocking BSFL densities were used during 20 batches, and quality and safety assessments were performed on the main outputs, namely BSFL production performance, frass impurities, larval and frass nutrient profiles and heavy metal content. About 1400 kg of former foodstuffs (fresh weight) were used to produce 239 kg BSFL and 230 kg frass. The production of BSFL reared on former foodstuffs was highly efficient, with feed conversion rates (FCR) ranging between 2.3 and 5.5 (dry matter basis). The optimization experiment revealed that former foodstuffs-based mixture and high larval density (10 larvae/cm2) lead to highly efficient (FCR: 2.6) and heavy metal-free production of BSFL and frass. The quality of the derived BSFL meal was high in terms of protein and amino acids. Furthermore, the quality of the technical frass was high in terms of N, P, and K levels and minimal packaging material residuals (<2.65%). This investigation suggests that nutrients in former foodstuffs can be successfully and safely recycled in production of BSFL