Investigation of the influence of the properties of the pressed material on the energy consumption and design parameters of the oil press

The article presents ways to obtain alternative sources of protein and fat from perennial crops and insects. The main properties of the material influencing the process of extracting fat from insects are considered. According to the results of the studies, the optimal technological parameters of the dried Hermetia illucens larva were revealed when pressing the fat. The optimum mass fraction of moisture is 15%. At a moisture content of insect biomass of 15%, fat filtration occurs at a pressure of 2.5 MPa. Microwave treatment of the material before pressing reduces the pressure at which the fat is squeezed out – 1.9 MPa at a material heating power of 1000 W. The intensity of heating does not significantly affect the acid number of the fat. Therefore, the most optimal heating power is 1000 W. The granulometric composition of the insect biomass also influences the fat squeezing process. Before pressing the fat, it is necessary to grind the larva to the size of particles passing through a 1 mm sieve in an amount of at least 60% of the total mass. The preparation of the material for the squeezing process has a significant effect on the energy consumption of the process. With a granulometric composition of particles of 1 mm, a moisture content of 15% and heating with a microwave power of 1000 W to 60° C, it provides a process that is 2 times less energy-intensive compared to pressing fat from an unprepared material.

Relationship of insect biomass and richness with land use along a climate gradient

Recently reported insect declines have raised both political and social concern. Although the declines have been attributed to land use and climate change, supporting evidence suffers from low taxonomic resolution, short time series, a focus on local scales, and the collinearity of the identified drivers. In this study, we conducted a systematic assessment of insect populations in southern Germany, which showed that differences in insect biomass and richness are highly context dependent. We found the largest difference in biomass between semi-natural and urban environments (−42%), whereas differences in total richness (−29%) and the richness of threatened species (−56%) were largest from semi-natural to agricultural environments. These results point to urbanization and agriculture as major drivers of decline. We also found that richness and biomass increase monotonously with increasing temperature, independent of habitat. The contrasting patterns of insect biomass and richness question the use of these indicators as mutual surrogates. Our study provides support for the implementation of more comprehensive measures aimed at habitat restoration in order to halt insect declines.

PROSPECTS FOR THE USE OF A PULSED ELECTRIC FIELD IN THE PROCESSING OF INSECT BIOMASS

Поиск альтернативных источников белка (микроводоросли, биомасса насекомых) создает необходимость разработки новых перерабатывающих технологий или адаптации существующих с учетом сохранения ценных компонентов сырья. Рассмотрено применение импульсного электрического поля (ИЭП) для обработки биомассы личинок мухи черная львинка (Hermetia Illucens) с последующей конвертацией в пищевые ингредиенты. Исследовали выживаемость личинок насекомых при применении ИЭП, а также определяли эффективность его воздействия как этапа предварительной обработки биомассы насекомых на выход ценных компонентов сырья – белка и жира в составе жмыха, масла и содержащихся в нем жирных кислот и аминокислот. Обработку ИЭП осуществляли с помощью положительных прямоугольных импульсов при напряженности электрического поля 2 и 3 кВ/см и затрачиваемой удельной энергией 5, 10 и 20 кДж/кг на промышленной установке PEF-Cellcrack II Elea (Германия). Масло извлекали горячим прессованием. Показано, что при величине напряженности электрического поля 3 кВ/см и затрачиваемой удельной энергии 5 кДж/кг все насекомые теряют жизнеспособность; их ткани после обработки ИЭП становятся более рыхлыми. Установлено, что применение ИЭП не изменяет качественного состава компонентов полученного масла. Изменение параметров ИЭП при обработке образцов биомассы насекомых существенно не влияет на процесс извлечения масла и содержание жирных кислот и аминокислот в нем. Предварительная обработка биомассы насекомых способствует увеличению выхода масла на 2,5%, аминокислот на 5,7% по сравнению с контрольным образцом без обработки ИЭП. Результаты исследования позволяют рекомендовать применение ИЭП в качестве этапа подготовки биомассы насекомых перед дальнейшей переработкой. The search for alternative sources of protein (microalgae, insect biomass) creates the need to develop new processing technologies or adapt existing ones, taking into account the preservation of valuable raw materials. The use of a pulsed electric field (PEF) for processing the biomass of the larvae of the black lion fly (Hermetia Illucens) with subsequent conversion into food ingredients is considered. We studied the survival of insect larvae when using PEF, and also determined the effectiveness of its effect as a stage of pretreatment of insect biomass on the yield of valuable raw material components – protein and fat in the composition of cake, oil and the fatty acids and amino acids contained in it. Treatment with pulsed electric fields was carried out using positive rectangular pulses at electric field strength of 2 and 3 kV/cm and expended specific energy of 5, 10 and 20 kJ/kg at the PEF-Cellcrack II industrial unit (Elea, Germany). The oil was extracted by hot pressing. It is shown that when the electric field strength is 3 kV/cm and the specific energy consumed is 5 kJ/kg, all insects lose their viability; their tissues become looser after PEF treatment. It is established that the use of PEF does not change the qualitative composition of the components of the resulting oil. Changes in the PEF processing parameters of insect biomass samples do not significantly affect the oil extraction process and the content of fatty acids and amino acids in it. Pretreatment of insect biomass contributes to an increase in the yield of oil by 2,5%, amino acids by 5,7% compared to the control sample without PEF treatment. The results of the study allow us to recommend the use of PEF as a stage of preparation of insect biomass before further processing.

Substrate as insect feed for bio-mass production

Insects are able to convert organic material (i.e. waste and by products) into high-quality biomass, which can be processed into animal feed. Several studies have investigated the influence of growing substrates on the nutritional value of different insect species, particularly black soldier fly larvae and prepupae. This article reviews studies on how insects bioconvert different substrates, the effect of the substrate on the composition of insect meals, and on the development time (time needed to reach the harvesting state). All these studies indicate that insects convert low and high quality organic material (i.e. waste, by products, compound feeds) into high-quality insect biomass. The role and effects of selected nutrients, such as ether extract/fats, carbohydrates and fibre in the substrate, seem to be key factors in defining the features of the biomass as well as the time needed to reach the harvesting state.

USING INSECT BIOMASS FOR RAINBOW TROUT CULTIVATION IN AQUACULTURE (FOREIGN LITERATURE REVIEW)

The article focuses on the data from foreign literature on growing rainbow trout or mykiss (Oncorhynchus mykiss) with the inclusion of dried and / or fat-free insect biomass in diets. The following seven types of insects could be recommended for inclusion in the diet of rainbow trout and other fish species: larvae and / or pupae of diptera fly (Hermetia illucens), housefly (Musca domestica), flour worm larva (Tenebrio molitor), locusts and grasshoppers (Acrididae), crickets (Gryllidae) and cathidids (Tettigoniidae), silkworm pupae (Bombyx mori). The brief data on physiology and life cycle of these insects are given, as well as the data on proteins and fatty acids concentration in fresh and dry larvae of insects. It has been shown that the flour from dried insect biomass contains a large amount of amino acids and fatty acids. There has been given the data on the influence of flour from insect larvae on the mass increase of rainbow trout juveniles and adults, digestibility of feed dry matter, organoleptic characteristics of fish fillets, amino acid and fatty acid composition, and other indicators. It has been found out that in most cases the survival rate is significantly higher in the experimental groups of Oncorhynchus mykiss juveniles fed a diet containing insect flour. It has been inferred that including flour from insect biomass in certain proportions has a positive effect on the growth and life of Oncorhynchus mykiss species. The most promising is adding Hermetia illucens larvae flour in the diet of rainbow trout in aquaculture, because Hermetia illucens larvae have the highest biomass yield per unit time compared to other insects.

Chemical ecology of an apex predator life cycle

Microbial symbiotic interactions, mediated by small molecule signaling, drive physiological processes of higher order systems. Metabolic analytic technologies advancements provide new avenues to examine how chemical ecology, or conversion of existing biomass to new forms, changes over a symbiotic lifecycle. We examine such processes using the tripartite relationship between nematode host Steinernema carpocapsae, its obligate mutualist bacterium, Xenorhabdus nematophila, and the insects they infect together. We integrate trophic, metabolomics, and gene regulation analyses to understand insect biomass conversion to nematode or bacterium biomass. Trophic analysis established bacteria as the primary insect consumers, with nematodes at trophic position 4.37, indicating consumption of bacteria and likely other nematodes. Significant, discrete metabolic phases were distinguishable from each other, indicating the insect chemical environment changes reproducibly during bioconversion. Tricarboxylic acid cycle components and amino acids were significantly affected throughout infection. These findings contribute to an ongoing understanding of how symbiont associations shape chemical environments.TeaserEntomopathogenic nematodes act as an apex predator in some ecosystems through altering chemical environments of their prey.

Insect reproductive behaviors are important mediators of carrion nutrient release into soil

Current declines in terrestrial insect biomass and abundance have raised global concern for the fate of insects and the ecosystem services they provide. However, the ecological and economic contributions of many insects have yet to be quantified. Carrion-specializing invertebrates are important mediators of carrion decomposition; however, the role of their reproductive activities in facilitating this nutrient pulse into ecosystems is poorly understood. Here, we investigate whether insects that sequester carrion belowground for reproduction alter soil biotic and abiotic properties in North American temperate forests. We conducted a field experiment that measured soil conditions in control, surface carrion alone, and beetle-utilized carrion treatments. Our data demonstrate that Nicrophorus beetle reproduction and development results in changes in soil characteristics which are consistent with those observed in surface carrion decomposition alone. Carrion addition treatments increase soil labile C, DON and DOC, while soil pH and microbial C:N ratios decrease. This study demonstrates that the decomposition of carrion drives soil changes but suggests that the behaviors of insect scavengers play an important role in the release of carrion nutrients directly into the soil by sequestering carrion resources in the ecosystem where they were deposited.