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The impact of blanching and storage temperature (−20 °C and −80 °C) on the formation of volatile organic compounds and changes in quality characteristics of lesser mealworm (Alphitobius diaperinus) larvae was examined over seven weeks. Acid and peroxide values, pH, and colour of lesser mealworm larvae were significantly affected by the studied variables. The changes in these characteristics as well as in the volatile profile indicated occurring lipid oxidation and lipid hydrolysis processes during the storage. The intensity of these reactions was mostly influenced by blanching treatment and storage time, and a lesser extent by storage temperature. It was proposed that changes in composition and intensity of volatiles can be used for rapid quality assessment of lesser mealworm larvae during frozen storage. Thus, the selection of optimum storage conditions for lesser mealworm larvae is important for the prevention of undesirable chemical reactions and preservation of the quality of insect biomass.

Processing of edible insects typically involves fractionating into high-value food ingredients, which results in by-products containing chitin and insoluble proteins. This study examined the effectiveness of lactic acid bacteria (LAB) in removing proteins from chitin in insect processing residues. Lesser mealworm processing residues were biologically treated for 48 and 120 h using LAB strains without added carbon sources. Results showed partial deproteinization, up to 29 % with Levilactobacillus brevis after 120 h. Most LAB grew up to 2 log10 colony-forming units/mL in the first 48 h. Confocal microscopy and Fourier-transform infrared spectra indicated that some protein remained attached to chitin. The molecular weight of solubilized proteins was affected by strain and time of incubation, with antioxidant activity increasing significantly after 120 h with Lacticaseibacillus paracasei. The biological treatment of insect processing streams can be a sustainable approach to producing high amounts of LAB biomass with subsequent protein solubilization and chitin release.

Lesser mealworm protein concentrate (LMPC) was conjugated with chlorogenic acid (CA) or tannic acid (TA) using an alkaline method. The impact of polyphenol type and concentration on the physicochemical and structural characteristics, antioxidant, interfacial, and emulsifying properties of the LMPC-polyphenol conjugates were investigated. Under the conditions tested, TA demonstrated higher affinity for LMPC compared to CA. The conjugation of LMPC induced conformational changes as showed by intrinsic fluorescence and FT-MIR raw spectra analysis. The surface hydrophobicity of the conjugates was reduced, leading to increased interfacial tension values for LMPC-TA conjugates without impairment of the emulsifying activity. The antioxidant properties were significantly improved by the conjugation. Flaxseed oil-in-water (O/W) emulsions stabilized by the conjugates and LMPC remained physically stable for 12 days at 50 °C with a notable reduction of secondary oxidation products when conjugates were used. LMPC-TA and LMPC-CA exhibited potential to be used as novel antioxidant emulsifiers in O/W emulsions.

During the processing of insects for food and feed applications, thermal treatments are often used for decontamination purposes. However, these treatments denature proteins comprising their functional properties. Milder methods for microbiological decontamination can be used, such as microfiltration. Therefore, in this study dead-end microfiltration (0.2 µm polyethersulphone membrane) was tested for decontamination of soluble fractions of lesser mealworms and house crickets obtained at pH values of 3 and 8. The results showed that dead-end microfiltration was successful in the removal of microorganisms (total viable count), removing the need for thermal treatments for the permeates. Protein recovery in the permeate was relatively low (14–43 %). Lesser mealworms at pH 3 gave the highest protein recovery in the permeate (43 %), as explained by the activity of endogenous proteases producing soluble peptides during microfiltration. Confocal imaging showed that the efficiency of microfiltration was reduced by membrane fouling caused by protein aggregation. The presence of lipids in the pre-filtrate does not hamper the permeate protein recovery. In conclusion, dead-end microfiltration with a 0.2 µm membrane is successful in achieving microbial stability. A pH of 3 is recommended during the extraction process to obtain a higher protein recovery.

Lesser mealworm (Alphitobius diaperinus) is an insect species that can be reared on an industrial scale for human consumption. In this study, the hydration behavior of processed lesser mealworm food ingredients (whole powder, protein concentrate, textured protein) was analyzed in comparison to whey protein concentrate and tofu. Moisture adsorption isotherms were determined gravimetrically over 0.11–0.96 water activity range at 5 and 20 °C, and seven sorption models were applied to fit the experimental data. The Guggenheim-Anderson-de Boer model performed best on the isotherms of all studied samples. The determined adsorption isotherms were type III according to Brunauer classification. Mealworm protein concentrate presented the strongest hydration capacity at 20 °C, followed by whey protein concentrate and whole mealworm powder. Textured mealworm protein and tofu exhibited similar hydration behavior at 5 °C. Moreover, browning and agglomeration of mealworm protein concentrate powder were observed at water activities of 0.73 and higher, which can be explained by its composition and porous structure and were not typical for whey protein concentrate. The moisture adsorption results are important for the prediction of lesser mealworm ingredients shelf-life or prevention of undesirable quality changes during storage, but more research on microbial growth and sensory quality is needed.

Water-in-oil-in-water (W1/O/W2 ) emulsions are complex delivery systems for polyphe-nols amongst other bio-actives. To stabilize the oil–water interphase, dairy proteins are commonly employed, which are ideally replaced by other, more sustainable sources, such as insect proteins. In this study, lesser mealworm (Alphitobius diaperinus) protein concentrate (LMPC) is assessed and compared to whey protein (WPI) and pea protein (PPI), to stabilize W1/O/W2 emulsions and encapsulate a commercial polyphenol. The results show that LMPC is able to stabilize W1/O/W2 emulsions comparably to whey protein and pea protein when using a low-energy membrane emulsification system. The final droplet size (d4,3) is 7.4 µm and encapsulation efficiency is between 72 and 74%, regardless of the protein used. Under acidic conditions, the LMPC shows a similar performance to whey protein and outperforms pea protein. Under alkaline conditions, the three proteins perform similarly, while the LMPC-stabilized emulsions are less able to withstand osmotic pressure differences. The LMPC stabilized emulsions are also more prone to droplet coalescence after a freeze–thaw cycle than the WPI-stabilized ones, but they are the most stable when exposed to the highest temperatures tested (90?C). The results show LMPC’s ability to stabilize multiple emulsions and encapsulate a polyphenol, which opens the door for application in foods. © 2021 by the authors. Licensee MDPI, Basel, Switzerland.

The effect of frozen storage on the chemical properties and ingredient functionalities of Lesser mealworms was investigated at −20 °C for 2 months. Major changes occurred in the first week of frozen storage. Proteins, among which heavy chain myosin, underwent denaturation and aggregation, as shown by a decrease in solubility, SDS-PAGE pattern, and Confocal Laser Scanning Microscopy. The ice melting point in larvae was −32.5 °C as determined by DSC: 25% of water is not frozen at −20 °C, possibly due to anti-freezing proteins preventing ice formation. The presence of unfrozen water favoured various enzymatic activities as shown by a pH decrease, indicating protein hydrolysis. The molecular changes during frozen storage increased the browning reactions due to phenoloxidase activity. Foaming ability, foam stability and gel network stability increased upon frozen storage due to protein denaturation. Results provide important information regarding the opportunity of frozen storage of insect larvae for both research and industrial purposes.

Insects are considered a nutritionally valuable source of alternative proteins, and their efficient protein extraction is a prerequisite for large-scale use. The protein content is usually calculated from total nitrogen using the nitrogen-to-protein conversion factor (Kp) of 6.25. This factor overestimates the protein content, due to the presence of nonprotein nitrogen in insects. In this paper, a specific Kp of 4.76 ± 0.09 was calculated for larvae from Tenebrio molitor, Alphitobius diaperinus, and Hermetia illucens, using amino acid analysis. After protein extraction and purification, a Kp factor of 5.60 ± 0.39 was found for the larvae of three insect species studied. We propose to adopt these Kp values for determining protein content of insects to avoid overestimation of the protein content.

This work was developed with the objective to evaluate the neem (Azadirachta indica) bioactivity, on peanut pods. To accomplish this study, selected pods were weighted and put in “raffia” bags (25 cm in length and 19 cm width) and kept in plastic recipients (10 cm in height, 19 cm in length and 13 cm width). Pod treatments was done using emulsifiable concentrate (Neemseto, 40%), neem oil and powder. A control was also used, having each treatment with five replications. For each replication 20 adult insects was used, not sexed and up to 30 days of age. The evaluation were accomplished at 30, 60, 90, 120, 150 e 180 days after the bioassay installation. The products efficiency base on neem on A. diaperinus was calculated by Abbott method, to evaluation at 30 days and the formula of Sun Shepard to the evaluation at 60, 90, 120, 150 e 180 days of peanut storage. According to the results it was concluded that the most efficient products were the emulsifiable concentrate and the neem oil; the tested products did not influenced., Este trabalho foi desenvolvido com o objetivo de avaliar a bioatividade de nim (Azadirachta indica) (A.Juss) sobre Alphitobius diaperinus (Panzer), em vagens de amendoim. Para realização do estudo, vagens foram selecionadas, pesadas e colocadas em sacos de ráfia (25 cm de comprimento x 19 cm de largura e acondicionados em recipientes plásticos (10 cm de altura x 20 cm de comprimento x 13 cm de largura) O tratamento das vagens foi realizado utilizando-se concentrado emulsionável de nim (Neemseto, 40%), óleo de nim e pó da folha de nim. cada tratamento foi repetido cinco vezes. Para cada repetição foram utilizados 20 insetos na fase adulta, não sexados e com idade de até 30 dias após a emergência. As avaliações foram feitas aos 30, 60, 90, 120, 150 e 180 dias após instalação do bioensaio. A eficiência dos produtos à base de nim sobre A. diaperinus foi calculada pelo método de Abbott, para a avaliação aos 30 dias e Sun Shepard para as avaliações aos 60, 90, 120, 150 e 180 dias do armazenamento. De acordo com os resultados pode-se concluir que os produtos mais eficientes foram o concentrado emulsionável e óleo de nim.

This work was developed with the objective to evaluate the neem (Azadirachta indica) bioactivity, on peanut pods. To accomplish this study, selected pods were weighted and put in “raffia” bags (25 cm in length and 19 cm width) and kept in plastic recipients (10 cm in height, 19 cm in length and 13 cm width). Pod treatments was done using emulsifiable concentrate (Neemseto, 40%), neem oil and powder. A control was also used, having each treatment with five replications. For each replication 20 adult insects was used, not sexed and up to 30 days of age. The evaluation were accomplished at 30, 60, 90, 120, 150 e 180 days after the bioassay installation. The products efficiency base on neem on A. diaperinus was calculated by Abbott method, to evaluation at 30 days and the formula of Sun Shepard to the evaluation at 60, 90, 120, 150 e 180 days of peanut storage. According to the results it was concluded that the most efficient products were the emulsifiable concentrate and the neem oil; the tested products did not influenced., Este trabalho foi desenvolvido com o objetivo de avaliar a bioatividade de nim (Azadirachta indica) (A.Juss) sobre Alphitobius diaperinus (Panzer), em vagens de amendoim. Para realização do estudo, vagens foram selecionadas, pesadas e colocadas em sacos de ráfia (25 cm de comprimento x 19 cm de largura e acondicionados em recipientes plásticos (10 cm de altura x 20 cm de comprimento x 13 cm de largura) O tratamento das vagens foi realizado utilizando-se concentrado emulsionável de nim (Neemseto, 40%), óleo de nim e pó da folha de nim. cada tratamento foi repetido cinco vezes. Para cada repetição foram utilizados 20 insetos na fase adulta, não sexados e com idade de até 30 dias após a emergência. As avaliações foram feitas aos 30, 60, 90, 120, 150 e 180 dias após instalação do bioensaio. A eficiência dos produtos à base de nim sobre A. diaperinus foi calculada pelo método de Abbott, para a avaliação aos 30 dias e Sun Shepard para as avaliações aos 60, 90, 120, 150 e 180 dias do armazenamento. De acordo com os resultados pode-se concluir que os produtos mais eficientes foram o concentrado emulsionável e óleo de nim.

Mechanical barriers consisting of bands of polyethylene terepthalate resin attached to wooden posts by latex caulk adhesive and staples were 100% effective in preventing passage of dispersing lesser mealworm, Alphitobius diaperinus (Panzer), larvae in the laboratory. Barriers continued to be 100% effective after being held in a caged layer poultry house for 3 mo. Polyethylene terepthalate barriers installed on support posts in a pullet house in Brooker, FL, were>92% effective against natural populations of lesser mealworm larvae 6 mo. after installation. The barriers also were >94% effective against natural populations of larvae of the hide beetle, Dermestes maculatus DeGeer, when fly populations were low. Fecal spot depositions by house flies in excess of 31 cumulative fly spots per square centimeter on spot cards reduced the effectiveness of the barriers to 79-90%, and barrier efficacy was reduced to 40-56% when fly spots covered >80% of the surface of the plastic. Washing the barriers with water to remove fly spots restored their effectiveness against hide beetle larvae to >99%.