Insect Powder Research Articles

Honeybee products and edible insect powders improve locomotive and learning abilities of Ubiquilin-knockdown Drosophila

BackgroundMutations in the human Ubiquilin 2 gene are associated with neurodegenerative diseases such as amyotrophic lateral sclerosis (ALS) with or without frontotemporal dementia (FTD), the fatal neurodegenerative disease that progressively affected neuronal cells in both brain and spinal cord. There is currently no effective therapy for these diseases. Over the last decade, researchers have focused on the potential use of natural products especially in neurodegenerative studies. Insect products have been used as traditional medicines, however, scientific information is still lacking. Fruit fly is recently used as a model organism to investigate degenerative diseases related to the nervous system because it has a short life span and produces a large number of offspring.MethodsThe present study investigated the effects of honeybee products and edible insect powders on the locomotive and learning abilities, neuromuscular junctions (NMJs) structure, and reactive oxygen species (ROS) in larval brains of Ubiquilin- knockdown Drosophila.ResultsdUbqn knockdown flies showed defects in locomotive and learning abilities accompanied with structural defects in NMJs. The results obtained revealed that the recovery of locomotive defects was significantly greater in dUbqn knockdown flies fed with coffee honey from Apis cerana (1% v/v) or Apis dorsata melittin (0.5 μg/ml) or wasp powder (2 mg/ml) than that of in untreated dUbqn knockdown flies. Furthermore, dUbqn knockdown flies fed with coffee honey showed the partial rescue of structural defects in NMJs, improved learning ability, and reduced the accumulation of ROS caused by dUbqn depletion in the brain over the untreated group.ConclusionThese results suggest that coffee honey from Apis cerana contains a neuroprotective agent that will contribute to the development of a novel treatment for ALS/FTD.

Drying methods differentially alter volatile profiles of edible locusts and silkworms

In this study, the effect of freeze-drying, oven- and microwave-drying on the volatile profiles and sensory properties of edible locust and silkworm was studied. Fifty-five headspace volatiles were detected, including alkanes, alcohols, aldehydes, esters, and ketones, with variations in intensity depending on the insect species and drying method. Volatiles from microwave-dried locusts and silkworms were typical for the Maillard reaction, that is in accordance with the significant increase of fluorescence of advanced Maillard products (2.9 and 5.5 times higher than in raw silkworms and locusts, respectively). Comparison of fatty acid composition and Fourier transform infrared spectra revealed signs of oxidation process at different levels depending on the insect. Changes in aroma and its intensity caused by different drying methods were also detected by sensory panellists who rated the samples of oven-dried locusts (2.4) and microwave-dried silkworms (1.9) with the lowest scores. An addition 15% of dried insects to cookies decreased the diversity of the volatiles, changed their intensity and lessened the dissimilarities between cookies with differently dried insect powders. Sensory panellists determined the presence of additional ingredients by higher odour intensity and general changes in overall liking scores of the insect-based cookies. Thus, drying can modify odour and sensory characteristics of locusts and silkworms and, consequently, cookies with these insect species, that should be considered in the processing of insects and formulation of novel insect-based foods.

Physicochemical Properties and Consumer Acceptance of Bread Enriched with Alternative Proteins.

A projected global population growth by 2050 and climate change crises have led to increasing demand in edible protein sources; thus, scientific research and food industries are searching for alternatives. In this study, we investigated the incorporation of plant- and insect-based protein sources in wheat-based formulations. The Alveographic properties of dough and the effects on bread physicochemical and sensory characteristics were analysed. Including pea protein or insect powder improved the nutritional value, increasing protein content, but influenced the dough and bread properties. Pea protein significantly increased the dough extensibility (L), tenacity (P), and their ratio (P/L) in dough with insect blends and the control. Bread texture properties were significantly affected by the addition of pea and insect flour. Higher amounts of pea protein incorporation increased hardness values and showed a mean cell area lower than the control bread. Crust colour analysis showed significant differences concerning the control bread, while crumb colour was affected by the flour colour. Word association analysis showed insect bread was associated with an emotional dimension, wheat bread was linked with “tradition”, and pea bread was associated with “fruit and vegetable”.

In vitro culture of local isolate Semarang entomopathogenic Nematodes on insect powder media

This research aims to analyze the population of EPNs isolate of Semarang cultivated in liquid media containing cricket (Gryllus bimaculatus) and mealworm (Tenebrio molitor) powder. Each treatment combination (doses of powder 0.5; 1.0; 1.5 and 2.0 g) was replicated five times. Each investing 1000 infective juveniles at the first breeding. The EPNs population was calculated every week for 4 weeks. The data were analyzed by ANOVA, followed by Tukey’s test. The results showed EPNs isolate Semarang be able to reproduce in the liquid media with cricket and mealworm powder. The difference between insects had no significant effect on the EPNs population, but the dose of powder influenced significantly (α <0.05). The EPNs population on 2nd week showed no difference between control media, 0.5 g, and 1.0 g media, while doses of 1.5 and 2 g are significant. This study concluded that cricket and mealworm powder are effective as EPNs culture media replacing the in vivo method. The optimum doses in this study were 0.5 g insect powder, and harvesting is suggested to be conducted during the second week. This result can be an alternative to the mass cultivation of EPNs to the development of local bioinsecticides.

Consumer acceptability in the USA, Mexico, and Spain of chocolate chip cookies made with partial insect powder replacement.

In the last decade, consumer perception of protein as an important nutrient has increased exponentially and focused on alternative sources such as plant- or insect-based protein and microalgae. However, many consumers indicate that they do not consider insect ingredients, a potential source of high quality protein, to be a good choice in food products. But is it because of the sensory aspects? This consumer study was conducted in the United States of America, Mexico, and Spain to compare acceptability of a familiar product, chocolate chip cookies, in three "blind" variations: a control 100% wheat flour chocolate chip cookie, and two versions substituting 15% and 30% cricket flour for an equivalent amount of wheat flour. Two hundred consumers from each country were recruited and scored overall acceptability and acceptability of different sensory attributes for the three cookies. Acceptance was measured using a nine-point hedonic scale and a similar format was used for each attribute. US consumers did not find significant differences in liking between the control and 15% sample. The 30% cricket powder cookie showed a decrease in consumer acceptance. Mexican and Spanish consumers liked the 15% sample significantly more than the control and 30% sample. Spanish consumers also like the control more than the 30% sample. The substitution of 15% cricket powder does not negatively impact liking in this product and, in fact, may improve both liking and protein content. Further research is necessary to determine whether this finding can help to mitigate the impact of insect-containing ingredients. PRACTICAL APPLICATION: High protein and sustainability are two key aspects being used to promote products in many markets. The protein content and sustainability of insect-based ingredients could make more competitive baked products if certain negative aspects, such as sensory and emotional and psychological barriers, can be overcome. This study focused on three specific countries but products using insect powder as an ingredient have the potential to be used in other regions or countries as acceptable products. With the correct marketing, such products could become a competitive choice in the product category. The food industry should consider and explore different insect powders/flours as an alternative ingredient.

Edible insects: cricket farming and processing as an emerging market

This article provides information on recent trends in cricket farming and processing in Asian and Western countries. Whilst eating insects collected from the wild has long been a common practice in many countries, farming and transforming insects into a food ingredient for packaged products is a new development. Particularly in North America and Europe, some new, small companies are transforming cricket (and mealworm) powder into packaged food (energy bars, pasta, and chips among the examples). Within this article, two contrasting farming systems are principally considered. On one hand is the Thai cricket farming model, based on micro-farms, in which the small farmers do not make the flour; this task instead being handled by specialised businesses. On the other hand, is the western farming model, in which farms are large, and the flour is produced by the very same factory-farm. Examples of this model are found in the Netherlands (Protifarm) and Canada (Entomofarm). Since insect powders (flour) in packaged foods represent a new category of food product, little market data and/or surveys are available. The products are often sold on small online shops, within the context of an informal business operations. As a consequence, some of the information in this article comes from informal sources or the direct experience of the author.

Rapid discrimination and classification of edible insect powders using ATR-FTIR spectroscopy combined with multivariate analysis

Insects are being proposed as an alternative way to ensure world’s food and feed security. Methods to determine edible insect powder’s origin and species will be needed for quality control purposes. Infrared spectroscopy has been extensively used in rapid chemical fingerprinting of food products. The present research explores a new approach to discriminate and classify commercial edible insect powders using attenuated total reflectance mid-infrared spectroscopy combined with multivariate analysis. Infrared spectra of seven commercial edible insect powders from different species (Tenebrio molitor, Alphitobius diaperinus, Gryllodes sigillatus, Acheta domesticus andLocusta migratoria) and origins (the Netherlands and New Zealand) were collected to build up soft independent modelling of class analogy (SIMCA) models. SIMCA models clearly discriminated insects by their species and origin linking their differences to lipids and chitin. SIMCA models performance was tested using five spectra of each class not used to build up the training set. 100% correct predictions were obtained for all the samples analysed with the exception of one sample ofAlphitobius diaperinus. Infrared spectroscopy coupled to multivariate analysis provided a powerful method for the assurance of insect powder’s authenticity.

Research and industrialisation ofHermetia illucens L. in China

The larvae of the black soldier fly (BSF),Hermetia illucens L., are commonly associated with decaying organic wastes. Over the past 15 years, investigators in China have conducted extensive research exploring the use of BSF larvae to recycle organic materials as a means to protect the environment, while producing products of value, such as protein and bioenergy. Initial efforts were based on a BSF strain from the USA. However, since then,H. illucens strains from specimens collected in Hubei and Guangdong Provinces have been established and used as models to explore the use of this species in sustainable agriculture. China has played an instrumental role in developing an in-door breeding method using a quartz-iodine lamp rather than depend on natural sunlight. This discovery has allowed the establishment of in-door BSF colonies in regions throughout the world where abiotic conditions (i.e. cold temperatures) are preventative. Researchers in China paved the way for using microbes as a means to enhance BSF production including, enhancing BSF egg-laying as well as waste reduction. Furthermore, bacteria from BSF gut or waste can be cultured and used to promote BSF growth, shorten conversion time, and enhanced conversion efficacy. Recent efforts have demonstrated BSF larvae can degrade antibiotics as well as suppress noxious odours in livestock manure. Due to the efforts of research on BSF in China, numerous companies that recycle organic waste at a large scale (&gt;20 tonnes waste digested/day), have been established. Resulting products include insect powder, and live BSFL that can be used as animal feed ingredients for livestock (e.g. eels and frogs), while protecting the environment. Future work will decipher the mechanisms regulating BSF larval conversion of organic waste so that the system can be optimised. However, efforts are still needed at the government level to establish quality assurance standards if this process is truly to become established as an industry in China.

Silkworm pupae (Bombyx mori) and locusts as alternative protein sources for high-energy biscuits

Abstract This study explored the possibility of replacing skimmed milk – a core ingredient of High-energy biscuit (HEB), with edible-insects as inexpensive and sustainable alternative sources. HEB was formulated to meet the USAID 2016 (STD) nutritional standards and powdered locust and mulberry silkworm pupae (LP and SWP) at 15% inclusion, were used as alternative protein sources. Preliminary nutrients composition of the insect powders were examined. Physicochemical, sensory and microbial qualities of insect-enriched biscuits (LPB and SWPB) were evaluated and compared with that of skimmed milk (SMB) and STD. Spread ratios of the biscuits were between 7.8 and 11.6 – a technically acceptable range for biscuits. SWP possessed impressive amounts of protein (60.7 g/100 g), fat (23.5 g/100 g) and energy contents (498.93 kcal/100 g), while LP had slightly more fibre (1.4 g/100 g), ash (2.1 g/100 g) and carbohydrate (31.5 g/100 g). LPB and SWPB had relatively similar proximate compositions as SMB with slight variations, and all the HEBs were above USAID minimum standard. SWPB was marginally below requirements for Ca and Mg minerals, but both (SWPB and LPB) had more than twice the recommended pro-vitamin A (918.44 and 957.65 µg/100 g) and vitamin C contents (102.17 and 98.51 mg/100 g). All the samples received reasonably good sensorial rankings; but SMB’s aroma was preferred. Similarly, microbial quality assessment of the products reflected remarkable hygienic sample preparation. These results demonstrated that HEB of significant nutritional, sensorial and microbial qualities could be developed using edible-insects as alternative protein sources.

Glucose-lowering effect of Gryllus bimaculatus powder on streptozotocin-induced diabetes through the AKT/mTOR pathway.

This study was carried out to elucidate the antidiabetic effects of Gryllus bimaculatus powder using a streptozotocin (STZ)‐induced rat model of type I diabetes. Administration of the insect powder significantly rescued representative diabetes markers (i.e., insulin and C‐peptide) in STZ‐treated rats. Improved glucose tolerance test (GTT) and insulin tolerance test (ITT) results were also observed, indicating that Gryllus bimaculatus powder exerts antidiabetic effects. Gryllus bimaculatus powder administration rescued STZ‐induced alterations in both islet morphology and insulin staining patterns. The extract increased antiapoptotic Bcl2 expression and decreased proapoptotic Bax and active caspase 3 expressions. In addition, the Gryllus bimaculatus powder supplementation enhanced AKT/mTOR pathway, a key marker of the state of anabolic metabolism, and its downstream effector, mTOR. Collectively, our results suggest that Gryllus bimaculatus contributes to the maintenance of pancreatic β‐cell function and morphology against a diabetic state through the regulations against apoptosis and anabolic metabolism.

Microbiological Profile and Bioactive Properties of Insect Powders Used in Food and Feed Formulations.

Microbiological, nutritional and bioactive properties of edible powders obtained from Acheta domesticus (house cricket) and Tenebrio molitor (mealworm) were investigated. Except for the enterobacteria, viable bacteria were at a higher concentration in mealworm flour. The diversity evaluation carried out using MiSeq Illumina that mainly identified Citrobacter and Enterobacteriaceae in mealworm powder and members of the Porphyromonadaceae family in house cricket powder. Enterococci were identified and characterized for their safety characteristics in terms of the absence of antibiotic resistance and virulence. Both powders represent a good source of proteins and lipids. The fatty acid profile of mealworm powder was characterized by the predominance of the monounsaturated fatty acids and house cricket powder by saturated fatty acids. The enzymatic hydrolysis produced the best results in terms of percentage of degree of hydrolysis with the enzyme Alcalase, and these data were confirmed by SDS-PAGE electrophoresis. Furthermore, the results showed that the protein hydrolysate of these powders produces a significant antioxidant power.

Buckwheat-pasta enriched with silkworm powder: Technological analysis and sensory evaluation

Our study presents the development and technological and sensory evaluation of silkworm enriched buckwheat pasta. Several publications deal recently with the enrichment of different food products with insects. Grain based products seem to be a promising field, due to the wide product range and their popularity. Though buckwheat is healthy, it is less liked by the consumers, because of its characteristic flavour profile. Our aim was to develop a silkworm enriched buckwheat pasta, which merges the advantages of the base materials, and masks the disliked flavour of buckwheat.Three products were created, insect-free, 5 g and 10 g silkworm/100 g pasta, respectively. Our calculations showed that silkworm powder increases the nutritional value of buckwheat pasta; the 5 g and 10 g/100 g enriched products had higher protein content, with reduced energy value. According to technological analyses silkworm reduces optimum cooking time, while increases the acidity of pastas over storage. Consumer sensory analysis proved that 10 g silkworm/100 g pasta product received the highest overall acceptance, while lowest values were assigned to the insect-free product. According to the obtained results, insect powder is a suitable material for enriching less liked, but basically healthy products.

Factors Predicting the Intention of Eating an Insect-Based Product.

This study provides a framework of the factors predicting the intention of eating an insect-based product. As part of the study, a seminar was carried out to explore how the provision of information about ecological, health, and gastronomic aspects of entomophagy would modify consumer beliefs regarding insects as food. Before and after the informative seminar, two questionnaires about sociodemographic attributes and beliefs about the consumption of insects as food were given. Participants were then asked to carry out a sensory evaluation of two identical bread samples, but one was claimed to be supplemented with insect powder. Results showed that perceived behavioral control is the main predictor of the intention, followed by neophobia and personal insect food rejection. The disgust factor significantly decreased after the participants attended the informative seminar. Sensory scores highlighted that participants gave “insect-labelled” samples higher scores for flavor, texture, and overall liking, nevertheless, participants indicated that they were less likely to use the “insect-labelled” bread in the future. Our findings provide a better understanding of insect food rejection behavior and help to predict the willingness to try insect-based products based on some important individual traits and information.

Protein quality and physicochemical properties of commercial cricket and mealworm powders.

The pressing need for protein supply growth gives rise to alternative protein sources, such as insect proteins. Commercial cricket and mealworm powders were examined for their protein quality, surface charge and functional attributes. Both insect powders had similar proximate compositions with protein and ash contents of ~ 66%db (dry weight basis) and 5%db, respectively, however cricket powder contained more lipid (16.1%, db) than mealworm powder (13.7%, db). Mealworm protein had an amino acid score of 0.71 and was first limiting in lysine, whereas cricket protein was first limiting in tryptophan with an amino acid score of 0.85. In vitro protein digestibility values of 75.7% and 76.2%, and in vitro protein digestibility corrected amino acid scores of 0.54 and 0.65, were obtained for mealworm and cricket powders, respectively. Zeta potential measurements gave isoelectric points near pH 3.9 for both insect powders. Mealworm and cricket powders had water hydration capacities of 1.62g/g and 1.76g/g, respectively, and oil holding capacities of 1.58g/g and 1.42g/g, respectively. Both insect proteins had low solubility (22-30%) at all pHs (3.0, 5.0, and 7.0) measured. Cricket powder had a foaming capacity of 82% and foam stability of 86%, whereas mealworm powder was non-foaming. Values for commercial pea and faba bean protein concentrates were reported for comparative purposes. The insect proteins had similar protein quality as the pulse proteins and had higher solubility at pH 5.0 but were much less soluble at pH 7.0.

Edible Insects but Not Solanum Torvum Improved Body Composition and Iron Status in Protein and Iron Deficient Rats (P24-007-19)

ObjectivesNutritious underutilized foods (NUFs) such as Solanum torvum (STO) and edible insects are potential sustainable dietary approaches to prevent malnutrition and improve food security. However, little is known about nutrient bioavailability from NUFs. This study determined the effect of STO and insect powders on improving nutritional status of malnourished rats. MethodsMalnutrition was induced in weanling male Sprague-Dawley rats by feeding 5% protein with low Fe (LPI) diet for 21 days. During 14-day repletion, 5 groups of rats (n = 8) were fed the LPI diet supplemented with cricket, palm weevil larvae, STO, cricket + STO and casein + ferrous sulfate (HPI, positive control) while another group remained on the LPI diet (negative control). Repletion diets contained 15% protein and 20 ppm Fe, but palm larvae diet contained only 10 ppm Fe. Body composition was measured by dual X-ray absorptiometry. Hemoglobin (Hb) repletion method was used to compare relative bioavailability (RBV) of the HPI group to the other groups. ResultsCollectively, there were no differences in improved growth rate and body composition measures in groups repleted with edible insects and HPI (P = 0.08). Growth rate was 7.9 times higher in HPI compared to STO and 4.2 times higher in HPI compared to LPI (P < 0.0001). Changes in body composition were similar in STO and LPI but significantly different from HPI. Increase in Hb Fe with cricket (2.00 ± 0.90 mg) and palm weevil larvae (1.17 ± 0.75 mg) was comparable to HPI (1.94 ± 0.74 mg) (P = 0.27). Compared to HPI, there were significant differences in Hb Fe with STO (−0.08 ± 0.37 mg) and LPI (0.55 ± 0.18 mg). When RBV was calculated based on Hb Fe and food intake, RBV was 1.3 for palm weevil larvae but this was not significantly different from HPI (RBV = 1.00) and cricket (RBV = 0.99) (P = 0.83). RBV was similar in STO and LPI, and 100 times lower compared to HPI (P < 0.0001). ConclusionsThough other benefits of STO may be plausible, no nutritional benefits were found in this study, but cricket and palm weevil larvae could be excellent alternative sources of protein and bioavailable Fe and can be sustainable, cheap and locally available foods to prevent malnutrition in humans in countries where they are culturally accepted. Funding SourcesDoris A. Adams endowment funds from the College of Human Sciences at Iowa State University, Ames.

Willingness to eat an insect based product and impact on brand equity: A global perspective

AbstractRapid population growth is creating the need to find new and sustainable food sources. Insect‐based products could satisfy this high priority necessity while incorporating important nutrients in the human diet such as protein, vitamins, and minerals. This research provides a global overview of the willingness to try a new product that contains insect powder and determine the impact of adding insect‐based products to a brands portfolio. An international survey was conducted in 13 different countries (n = 630 consumers per country, total 7,800 consumer) with consumers who represented diverse demographic backgrounds. Eight of the 13 countries could be classified as “disgust” countries where most respondents said they would not be willing to try a familiar product containing insect powder. Nine countries fell into the “impact” category where participants would be more likely to stop buying other products from this company knowing that they have used insect powder in another product from the same brand. The reasons why participants would not consider eating foods containing insect powder were religion, the perception that insects carry diseases and cause allergic reactions. Only the disease‐carrying perception was significant in most of the countries.Practical applicationsThe results from this study showed that most consumers from most countries studied are not willing to try insect‐based products at this time. However, there was a segment of the population in each country that was willing to try such products. There is a great opportunity for companies to create new products for countries where the disgust factor was not a barrier and to test those new concepts and products. This could help provide information to educate consumers about all the benefits of insect protein and implement. It is key to remember that new brands probably are necessary for such products because of the potential damage to brand equity of introducing products containing insect powder.

Enhanced entomopathogenic nematode yield and fitness via addition of pulverized insect powder to solid media.

Abstract Beneficial nematodes are used as biological control agents. Low-cost mass production of entomopathogenic nematodes (EPNs) is an important prerequisite toward their successful commercialization. EPNs can be grown via in vivo methods or in sold or liquid fermentation. For solid and liquid approaches, media optimization is paramount to maximizing EPN yield and quality. In solid media, the authors investigated the effects of incorporating pulverized insect powder from larvae of three insects (Galleria mellonella, Tenebrio molitor, and Lucillia sericata) at three dose levels (1, 3, and 5%). The impact of insect powder was assessed on infective juvenile (IJ) yield in solid media. Additionally, IJs produced in solid culture were subsequently assessed for virulence, and progeny production in a target insect, Spodoptera litura. The dose level of larval powder had a significant effect on IJ yield in both trials, whereas insect type had significant effect on IJ yield in trial 1 but not in trial 2. The maximum solid culture yield was observed in T. molitor powder at the highest dose in both trials. Moreover, the time-to-death in S. litura was substantially shortened in trial 1 and in trial 2 when IJs from the T. molitor powder treatment were applied. There was no significant effect of combining two insect powders relative to addition of powder from a single insect species. These findings indicate that addition of insect powder to solid media leads to high mass production yields, and the fitness of the IJs produced (e.g., in virulence and reproductive capacity) can be enhanced as well.

Effects of formulation and process conditions on microstructure, texture and digestibility of extruded insect-riched snacks

Abstract Extruded cereals made of wheat flour and grinded Yellow mealworm larvae (Tenebrio molitor) were produced to investigate the effect of insect inclusion (0%, 10%, 20%) and processing conditions (barrel temperature and screw speed) on their nutritional content, microstructure, texture and digestibility. Snacks enriched with 10% mealworm powder shifted their macronutrient composition towards a protein content high enough to claim the food as “source of protein” according to European food regulation. At 10% of enrichment, the adoption of high barrel temperature and screw speed significantly improved the microstructure, in terms of expansion and pore structure, delivering acceptable textural qualities. At 20% substitution, snacks showed poor expansion properties, mainly due to the presence of fat in the larvae. Starch and protein digestibility of were correlated with microstructure properties as a function of porosity, pore size and wall thickness. Interestingly, mechanical forces generated in extrusion likely improved the digestibility of T. molitor proteins which are tightly bound and sclerotized to the exoskeleton. Tailoring processing conditions and formulation insect ingredients can be successfully incorporated into extruded cereal snacks. Industrial relevance This study evaluated the nutritional and technological properties of extruded cereal snacks enriched with an edible insect powder (T. molitor). Results suggested that edible insects can be used as novel ingredient in extruded snacks and pointed out how processing conditions can modulate snack digestibility.

Exploring the potential of lipids from black soldier fly: New paradigm for biodiesel production (II)—Extraction kinetics and thermodynamic

Abstract This study investigated microwave extraction approach to extract lipids from the black soldier fly larval containing high lipids for biodiesel production. The comparison of the effects of different factors (solvent types, extraction temperature, and solute-solvent ratio) on the kinetics and thermodynamic of lipids extraction from the energy insect was investigated in detail. A mathematical model of lipids extraction from the pretreatment insect powder was proposed. The solid-solvent ratio and temperature can have a pronounced effect on lipids extraction rate k. The final yield of lipids increased by a factor of about 1.0–1.04 for extraction temperature elevated by 10 °C. The diffusion of lipids in the solvent constituted the limitation step in the process of extraction. The magnitudes of the diffusion coefficients range from 6.7 × 10−12–16.1 × 10−12 m2/s for three solvents used. The values of the activation energy Ea were 84.26 kJ mol−1 during the diffusion stage (30 °C–60 °C). At last, the three thermodynamic parameters results (ΔH, ΔS, ΔG) were also obtained from the extraction process.

Dynamics of amino acid redistribution in the carnivorous Venus flytrap (Dionaea muscipula) after digestion of 13 C/15 N-labelled prey.

Amino acids represent an important component in the diet of the Venus flytrap (Dionaea muscipula), and supply plants with much needed nitrogen resources upon capture of insect prey. Little is known about the significance of prey-derived carbon backbones of amino acids for the success of Dionaea's carnivorous life-style. The present study aimed at characterizing the metabolic fate of 15 N and 13 C in amino acids acquired from double-labeled insect powder. We tracked changes in plant amino acid pools and their δ13 C- and δ15 N-signatures over a period of five weeks after feeding, as affected by contrasting feeding intensity and tissue type (i.e., fed and non-fed traps and attached petioles of Dionaea). Isotope signatures (i.e., δ13 C and δ15 N) of plant amino acid pools were strongly correlated, explaining 60% of observed variation. Residual variation was related to contrasting effects of tissue type, feeding intensity and elapsed time since feeding. Synthesis of nitrogen-rich transport compounds (i.e., amides) during peak time of prey digestion increased 15 N- relative to 13 C- abundances in amino acid pools. After completion of prey digestion, 13 C in amino acid pools was progressively exchanged for newly fixed 12 C. The latter process was most evident for non-fed traps and attached petioles of plants that had received ample insect powder. We argue that prey-derived amino acids contribute to respiratory energy gain and loss of 13 CO2 during conversion into transport compounds (i.e., 2days after feeding), and that amino-nitrogen helps boost photosynthetic carbon gain later on (i.e., 5weeks after feeding).