Lipid Extracts Research Articles

Cell rupture of Tetradesmus obliquus using high-pressure homogenization at the pilot scale and recovery of pigments and lipids

Microalgae are promising sources of intracellular metabolites such as proteins, polysaccharides, pigments, and lipids. Thus, this study applied high-pressure homogenization (HPH) techniques on a pilot scale to disrupt the cells of Tetradesmus obliquus. The effects of pressure (P; 150, 250, and 350 bar), suspension concentration (Cs; 1.0, 1.5, and 2.0 % w/v), and number of cycles (Nc; 5, 15, and 25) were evaluated in HPH via a Box–Behnken experimental design. Response surface methodology was applied to optimize the recovery rate (dTr) of pigments and lipids. The specific energy consumption (SEC) and color change gradient (ΔE) of the biomass during HPH were also assessed. The optimal HPH conditions for pigment extraction with 1.5 % Cs (w/v) were as follows: P = 312 bar and Nc = 22 for chlorophyll-a (0.83 g/100 g; dTr = 69 %; SEC = 47.50 kJ/g dry matter); P = 345 bar and Nc = 24 for chlorophyll-b (0.63 g/100 g; dTr = 80 %; SEC = 57.30 kJ/g dry matter); P = 345 bar and Nc = 24 for total carotenoids (0.53 g/100 g; dTr = 79 %; SEC = 54.12 kJ/g dry matter); and P = 350 bar and Nc = 25 for β-carotene (299 µg/g; dTr = 58 %; SEC = 62.08 kJ/g dry matter). The optimal HPH conditions for lipid extraction were P = 350 bar and Nc = 23, with a lipid recovery rate of ≥28 %. Cell disruption during HPH caused a change in the color of the biomass (ΔE) due to the release of intracellular biocompounds. Increasing P and Nc led to higher SECs, ΔE gradients, and pigment and lipid contents. Thus, the levels of recovered pigments and lipids can be indicators of cell disruption in T. obliquus.

In vitro digestion study comparing a predigested glycerolysis product versus long-chain polyunsaturated fatty acid-rich oils (LCPUFA) as a strategy for administering LCPUFA to preterm neonates

Background & aimsMaintaining an adequate supply of arachidonic acid (ARA) and docosahexaenoic acid (DHA) is essential for optimal growth of preterm infants. This study aims to evaluate and compare the digestibility and bioaccessibility of ARA and DHA oils compared to their predigested product through an in vitro digestion model. MethodsAn in vitro gastrointestinal digestion model was used in two stages: gastric digestion and intestinal digestion. Samples of two polyunsaturated rich oils (ARA and DHA oils) and their predigested product (2:1, ARA: DHA) produced by enzymatic glycerolysis have been digested for 120 min. The final digestion product obtained was composed of three phases: an upper oily phase (OP) containing the undigested species, an intermediate micellar phase (MP) containing digested and bioaccessible lipids, and a precipitate phase (PP) with insoluble compounds. The reaction was monitored by taking aliquots and their subsequent lipid extraction and analysis. ResultsPoorer digestibility for ARA and DHA oils was observed based on the percentage of the oily phase (26.7% and 20%, respectively) found compared to the glycerolysis product (GP) oily phase (13.9%). The highest micellar phase was found in the GP (approx. 83%). On the other hand, the monoglyceride (MAG) content was lower in the digestion product (DP) from ARA and DHA oils, 4.3% and 9.2%, respectively, compared to the MAG observed in the DP of GP (15%). ConclusionConsidering the percentage of oily phase, micellar phase, and the MAG content, it can be concluded that the GP is more digestible and ARA and DHA are more bioaccessible than in its precursor oils.

Multifaceted Impact of Lipid Extraction on the Characteristics of Polymer-Based Sewage Sludge towards Sustainable Sludge Management.

Dewatered sludge (DS) is a sewage sludge with a unique property due to extracellular polymeric substances (EPSs) and polymer flocculants. These components form a stable 3D polymer network to increase dewatering efficiency, leaving behind valuable materials such as lipids. This article explored the influences of DS particle size on lipid yield and the effects of extraction on the chemical, morphological, and thermal properties of the residual dewatered sludge (RDS). Lipid yields with unimodal distribution were observed across the particle size ranges (<0.5, 0.5-1.0, 1.0-2.0, 2.0-4.0, and 4.0 mm). The highest lipid yield of 1.95% was extracted from 1.0-2.0 mm after 4 h at 70 °C and 0.1 g/mL sludge-to-solvent ratio. Efficiency was influenced by the DS's morphology, facilitating solvent infiltration and pore diffusion. The extraction process reduced water and organic fractions, resulting in higher thermal stability. Bibliometric analysis of "extraction*" and "sewage sludge" shows increasing research interest from 1973 to 2024. Five research clusters were observed: heavy metal speciation and stabilization, sludge and its bioavailability, extraction techniques and resource recovery, contaminants remediation, as well as phosphorus recovery and agricultural applications. These clusters highlight the diverse approaches to researching DS and RDS while promoting sustainable waste management.

Valorisation of Algerian agro-wastes as renewable biofuels: Impact of using microwave-assisted method on lipid extraction

Fossil fuels are the largest contributor to climate change, representing about 90% of carbon dioxide emissions. Given the environmental impact and the high prices around the world, finding an alternative solution has become necessary at the present time. Biodiesel, as a renewable energy, is considered one of the possible solutions to reduce these emissions since the CO2 emitted during combustion will be recycled again by nature for feedstock production. This process is known as a closed carbon cycle. The cost of producing biodiesel depends on the nature of the raw material and the production method which involves both oil extraction and its transformation to biodiesel. Our contribution lies in feedstocks choice and extraction method, namely, we provide a comparison between conventional extraction methods including maceration, Soxhlet and microwave-assisted extraction as an innovative method. The latter technique has been developed for the extraction of lipids from different agro-wastes available in Algeria. Our results show that MAE of lipid has proven its effectiveness in terms of rapid and powerful heating, particularly regarding extraction time, which was 1/6 and 2/3 of SE and ME extraction time respectively. The use of different extraction method has no obvious impact on the presence of functional groups, between dates' palm seeds and olive pomace lipids. However, it can be more significant when using ME.

Sustainable organic waste valorisation: A zero-waste approach

The annual increase in global organic waste generation emphasises the need to develop a sustainable management platform to address environmental concerns. This study aims to explore sustainable treatments for the conversion of organic waste into energy in pursuit of zero-waste. The organic waste generated from the animal feed industry (referred to as WF) was used for the model compound in this study. 8.5 wt% of lipids were extracted from the WF, which contained unidentified impurities. Acid-catalysed transesterification yielded less than 80 wt% biodiesel might be due to the reversible reaction. In contrast, non-catalytic transesterification resulted in a significantly higher biodiesel yield (95.6 wt%), suggesting that this method was more effective at converting impure lipids into biodiesel compared to acid-catalysed transesterification. These results indicate the potential advantages of the non-catalytic approach, particularly when dealing with impure lipid sources. To minimise the generation of waste in the process, the WF residue produced after lipid extraction was converted into combustible gas (syngas) through pyrolysis. CO2 was used as a reactive medium in pyrolysis. In one-stage pyrolysis, the gas yield under CO2 was comparable to that under N2, indicating that CO2 did not react effectively with the volatiles derived from the WF residue. Enhanced CO2 reactivity was achieved via catalytic pyrolysis using a nickel-impregnated catalyst. Consequently, the combustible gas yield under CO2 was much higher than that under N2. This approach might contribute to maximising the efficiency of converting organic waste into renewable energy while simultaneously consuming CO2 during pyrolysis, thereby enhancing the sustainability of this approach.

An interactive R-based custom quantification program for semi-quantitative analysis of triacylglycerols in bovine milk.

The R programming language, RStudio, and open-source software solutions for analysis of liquid chromatography-mass spectrometry (LC-MS) data have been used with user-written R-based custom quantification programs (CQP) for semi-quantification of triacylglycerols (TAGs) in bovine milk lipid extracts. Using the peak-finding capabilities of the package "xcms" in RStudio, peaks were integrated, and retention times aligned, normalized, and then used for semi-quantitative analysis of a custom set of four extraction internal standards (EISs) and 29 TAG regioisomers using the choice of four analytical internal standards (AISs). Alternating stereospecific numbering (sn) 1,3 TAG regioisomers (standards 1, 3, and 5 of six calibration standards) and sn-1,2 TAG regioisomers (standards 2, 4, and 6 of six standards) were used to make a set of six calibration standards, which were used for quantification using a linear fit model, polynomial fit model, power fit model, level-bracketed linear fit, replicate-bracketed polynomial fit, replicate-bracketed power fit, and replicate- and level-bracketed linear fit and response factors. For example, the linear fit for EIS1 gave an unacceptable coefficient of determination (CoD), r2 = 0.9616, whereas the polynomial fit gave r2 = 0.9908 and the power fit gave r2 = 0.9928, while the double-bracketed linear fit gave CoDs of r2 = 0.9960, 0.9848, and 0.9781 for the three brackets, yet gave the least % difference to known calibration concentrations. For unparalleled transparency, the CQP produced webpages that allowed every step in the data processing and quantification sequence to be verified and reproduced, and contained interactive figures. The data are publicly available using a digital object identifier (DOI). The R code can be downloaded and used with the downloadable data to reproduce the results, to modify the code and further customize the results, or to copy and paste and adapt the code to other quantification applications.

Multisample lipidomic profiles of irritable bowel syndrome and irritable bowel syndrome-like symptoms in patients with inflammatory bowel disease: new insight into the recognition of the same symptoms in different diseases.

Overlapping clinical manifestations of irritable bowel syndrome (IBS) and IBS-like symptoms in patients with inflammatory bowel disease (IBD-IBS) present challenges in diagnosis and management. Both conditions are associated with alterations in metabolites, but few studies have described the lipid profiles. Our aim was to pinpoint specific lipids that contribute to the pathogenesis of IBS and IBD-IBS by analyzing multiple biologic samples. Diarrhea-predominant IBS (IBS-D) patients (n = 39), ulcerative colitis in remission with IBS-like symptoms patients (UCR-IBS) (n = 21), and healthy volunteers (n = 35) were recruited. IBS-D patients meet the Rome IV diagnostic criteria, and UCR-IBS patients matched mayo scores ≤ two points and Rome IV diagnostic criteria. Serum, feces, and mucosa were collected for further analysis. Lipid extraction was carried out by ultra-performance liquid chromatography-high resolution mass spectrometry (UPLC-HRMS). Lipidomics of mucosa and serum samples significantly differed among the three groups. Feces showed the most altered lipid species, and the enrichment analysis of 347 differentially abundant metabolites via KEGG pathway analysis revealed that alpha-linolenic acid metabolism was significantly altered in the two groups (P < 0.01). The ratio of omega-6/omega-3 fatty acid were imbalance in serum samples. This study revealed a comprehensive lipid composition pattern between IBS-D patients and UCR-IBS patients. We found several distinctive lipids involved in alpha-linolenic acid metabolism, reflecting an imbalance in the omega-6/omega-3 fatty acid ratio. Compared to mucosa and serum samples, fecal samples might have more advantages in lipidomics studies due to the convenience of sample collection and effectiveness in reflecting metabolic information.

Extracts from Wheat, Maize, and Sunflower Waste as Natural Raw Materials for Cosmetics: Value-Added Products Reaching Sustainability Goals.

Agricultural waste is underutilized, and sometimes burning them has a negative impact on the environment and human health. This research investigates the untapped potential of extracts from maize, wheat and sunflower waste as natural materials for cutaneous, specifically, cosmetic application. The possibility of incorporating lipid and ethanol extracts from wheat, maize, and sunflower into creams was investigated together with their potential contribution to the structural and functional properties of the topical formulations. Results of the physicochemical characterization show that investigated extracts can be successfully incorporated into creams with satisfactory stability. All extracts showed a desirable safety profile and good antimicrobial activity against various microorganisms. Lipid extracts have proven to be promising structural ingredients of the oil phase, contributing to the spreadability, occlusivity, and emollient effect. Ethanol extracts influenced washability and stickiness of the formulation and could be considered as prospective ingredients in self-preserving formulations. The extracts affected the sensory properties of the creams, mainly the smell and color. These results suggest that the extracts from wheat, maize, and sunflower waste could be used as multifunctional natural ingredients for cosmetic formulations which can replace less sustainable raw materials. This also represents a valorization of waste and is in line with broader sustainability goals.

Seasonal Variability of Lipophilic Compounds in Oat (Avena sativa L.) Straw: A Comprehensive Chemical Study.

Oat straw, a residue of Avena sativa L., is recognized for its abundance in cellulose, hemicelluloses, and lignin. However, its potential as a source of lipophilic compounds within the framework of a biorefinery concept still remains unexplored. In this study, we conducted an extensive investigation into the content and chemical composition of the lipophilic compounds present in acetone extracts from oat straws of two distinct oat varieties, namely, Karen and Isaura. Furthermore, we examined their seasonal variability in content and composition in straw samples from oats planted in both spring and winter seasons. The extracted lipophilic compounds were predominantly composed of high molecular weight esters (26.0-38.1%), steroids (16.6-24.0%), n-fatty alcohols (10.9-20.7%), n-fatty acids (10.9-16.0%), and n-aldehydes (10.7-15.8%), with lower amounts of n-alkanes (1.1-3.0%), acylglycerides (2.3-3.8%), phytol and phytyl esters (0.6-2.9%), β-diketones (0.1-2.5%), triterpenoids (0.9-1.2%), tocopherols and tocopheryl esters (0.2-0.7%), 2-hydroxy fatty acids (0.1-0.2%), and n-alkylresorcinols (0.1%). Notably, these different classes of compounds exhibited variations in their contents depending on the oat variety and the specific planting season. Of particular interest was the Karen variety, which presented significant amounts of high molecular weight esters, free fatty acids, and acylglycerols, especially when it was cultivated during the winter season. These findings underline the potential of oat straw as a valuable resource for lipid extraction within a biorefinery context and emphasize the importance of selecting the appropriate variety and season for optimal lipid yield.

Two-Step Macromolecule Separation Process with Acid Pretreatment and High-Shear-Assisted Extraction for Microalgae-Based Biorefinery

A simple two-stage extraction and recovery method for macromolecules from microalgae biomass, termed CASS (concentrating the microalgae solution, acid pretreatment, high-shear-assisted lipid extraction, and separation), was developed. This method effectively processed the wet biomass of Chlorella sp. ABC-001 at a moderately low biomass concentration (50 g/L). The optimal conditions were acid pretreatment with 5 wt.% H2SO4 at 100 °C for 1 h, followed by high-shear extraction using hexane at 3000 rpm for 30 min. The acid pretreatment hydrolyzed carbohydrates and phospholipids, disrupting the cell wall and membrane, while high-shear mixing enhanced mass transfer rates between solvents and lipids, overcoming the hydraulic barrier at the cell surface. Within 10 min after completing the process, the extraction mixture achieved natural phase separation into water, solvent, and biomass residue layers, each enriched with carbohydrates, lipids, and proteins, respectively. The CASS process demonstrated high esterifiable lipid yields (91%), along with substantial recovery of glucose (90%) and proteins (100%). The stable phase separation prevented emulsion formation, simplifying downstream processing. This study presents the results on cell disruption, optimal acid treatment concentration, and high-shear mixing to achieve macromolecule separation, expanding the lipid-centric microalgal process to a comprehensive biorefinery concept.

Exploring the potential of Hermetia illucens larvae extracts: A promising approach for dermocosmetic formulations

Globally, the yearly disposal of 1.3 billion tonnes of food raises environmental and public health concerns. Black soldier fly (BSF) larvae present a sustainable solution, converting organic waste into nutrient-rich biomass. The extracted oil from BSF larvae, rich in fatty acids (FA), offers an eco-friendly alternative for the cosmetic industry. In this study, larvae sourced from a Portuguese company were fed olive pomace, a by-product of olive oil production.The lipidic sample extracted revealed a composition high in oleic acid, valuable for cosmetics. Investigating the biological activity of lipid extractions from larvae fed with olive pomace is a novel approach. Notably, the n-hexane ultrasound-assisted extraction method demonstrated potent antioxidant properties, and some extracts displayed antimicrobial activity. Five non-cytotoxic extracts; three with no relevant activity (IC50 from 236 to >400 μg/mL).These findings highlight BSF larvae as an environmentally friendly source of fatty acids, offering promising alternatives for diverse applications.

A novel method for non-destructive efficient green recovery of multiple high value products from microalgal cells with enzymatically enhanced permeability

A method is developed for simultaneous extraction of lipids, hydrocarbons and carotenoids from primary algal biomass without the need for cell sacrifice. Enzymatically predigested cells (from previous experiments) with enhanced permeability were used, for ‘milking’ with biocompatible solvent. The continuous non-destructive extraction of lipids and carotenoids from an improved permeabilized microalgal cell using crude enzyme concoctions and biocompatible solvents has not been reported so far. Oocystis sp. cells showed considerable viability following enzymatic pretreatment and extraction using dodecane which was verified through cell viability assays, and chlorophyll content. HPLC analysis confirmed the presence of lutein and zeaxanthin. GC-MS analysis showed the presence of omega-3 alpha linolenic acid, PUFAs, and phenolics, in enzymatically digested microalgal cells. The content of fatty acids and esters in enzyme treated samples was 57.18 %, and the enzyme with dodecane treated samples showed 31.4 % fatty acids and esters content. Omega-3 linolenic acid comprised 11.66 % in enzyme treated cells and showed a marginal increase of 12.5 % in enzyme with dodecane treated cells. The method enables recovery of multiple compounds from a single biomass. In the present study, a cultivation strategy of microalgal cells with enhanced permeability, grown in biocompatible solvent is proposed, whereby maximum yield of multiple valuable metabolites can be obtained from a single biomass. The method simplifies downstream processing operations by circumventing cell harvesting and drying. The use of green extraction solvents reduces the overall carbon footprint of the process.

Efficacy of lipid extract of marine green alga Codium fragile (Suringar) Hariot for repair of mouse red cells membranes under stress exposure

Efficacy of lipid extract of marine green alga Codium fragile (Suringar) Hariot for repair of mouse red cells membranes under stress exposure

Microwave Heating Characteristics on Lipid Quality in Sterilized Rainbow Trout (Oncorhynchus mykiss) Using Designed Heating Processing.

The aim of this study was to simulate microwave heating characteristics to investigate the lipid quality in rainbow trout, including the impact of the heating rate, maximum temperature, and thermal processing level on the extent of lipid oxidation and on the fatty acid extraction coefficient. Increasing F0 from 3 to 6 min improved fatty acid retention at high heating rates but led to a decrease in the measured results at low heating rates. Elevated thermal processing levels and maximum temperatures were observed to intensify the oxidation. At F0 = 3 min, an increase in maximum temperature led to an increase in the total lipid extraction coefficient but a decrease in the fatty acid extraction coefficient. However, an increase in maximum temperature resulted in a decrease in both extraction coefficients when F0 was 6 min. The coefficient spectra of fatty acid extraction obtained from the microwave and traditional heat treatments showed nonparallel trends, confirming the presence of non-thermal effects during microwave thermal processing. In conclusion, compared to conventional heat treatment methods, microwave processing has significant potential for enhancing the lipid quality of ready-to-eat rainbow trout products and effectively reducing production costs.

Whole tomato lipidic extract improved sperm quality in obese rats induced by a high-carbohydrate diet.

Obesity represents a risk in the development of metabolic and oxidative stress (OS), as well as in male infertility. There is still no pharmacological treatment for obesity-induced male infertility, but the use of natural antioxidants has been proposed as a treatment. The aim of this work is to evaluate the effect of a whole tomato lipid extract on rats that decreased their fertility and spermatogenesis after being induced obese with a high carbohydrate diet. One hundred fourteen male Wistar rats of 12weeks of age were used. Two groups were randomly formed non-obese control group (C, n=54) and obese group (Ob, n=54) that received 30% w/v sucrose solution for 3 months. Subsequently, the C and Ob group were divided into two groups: vehicle (C-Vh and Ob-Vh) that received corn oil as vehicle and tomato lipid extract (C-Ex and Ob-Ex) that received whole tomato lipid extract. The groups that received a hypercaloric diet had a gain in visceral and retroperitoneal adipose tissue, an increase in total cholesterol and triglyceride levels, increased OS in the testis, and lesions in testicular histology, as well as a reduction in testicular size and sperm quality parameters (motility, viability, and concentration). Treatment with whole tomato lipid extract significantly decreased the weight of gonadal adipose tissue and OS, maintained testicular size, showed a significant increase in sperm quality parameters and improved histology of seminiferous tubules. These results demonstrate a greater therapeutic and beneficial effect of the tomato lipid extract on sperm quality parameters in obese rats and therefore on fertility.

Iridaea cordata lipid extract associated with the rCP01850 protein of C. pseudotuberculosis elicited a Th1 immune response in immunized sheep

Sheep farming contributes to the socioeconomic development of small and medium-scale livestock farmers. However, several factors can hinder successful animal production, as is the case for infectious diseases, such as the one caused by Corynebacterium pseudotuberculosis, known as caseous lymphadenitis (CLA). CLA has >90% prevalence in Brazilian herds and antibiotic treatment is not effective, consequently causing significant economic losses to farmers. Given the above, effective vaccines need to be developed to prevent this disease. This study aimed to evaluate the adjuvant activity of the lipid extract from the macroalgae Iridaea cordata as a candidate for developing an effective vaccine formulation. For such, four groups of six sheep each were inoculated with sterile 0.9% saline solution (G1), rCP01850 (G2), rCP01850 + I. cordata (G3), and rCP01850 + saponin (G4). Each sheep received two vaccine doses 30 days apart. Total IgG production levels significantly increased in experimental groups G3 and G4 on days 30, 60, and 90. On day 90, G3 showed higher total IgG production (p < 0.05) when compared to G4. When analyzing cytokine production, G3 was the only experimental group with significantly increased IFN-γ, IL-12, TNF-α, and IL-10 mRNA expression levels. Our results show the vaccine formulation containing rCP01850 adjuvanted with the I. cordata lipid extract elicited a Th1 immune response in sheep, indicating I. cordata lipid extract may be a promising adjuvant for developing an effective vaccine against infection caused by C. pseudotuberculosis.

Simultaneous extraction of oil, protein and polysaccharide from Idesia polycarpa Maxim cake meal using ultrasound combined with three phase partitioning

This study explored the potential of ultrasonic-assisted three-phase partitioning (UTPP) to simultaneously extract lipids, proteins, and polysaccharides from Idesia polycarpa Maxim (IPM) cake meal, a significant byproduct of oil extraction. The impact of variables such as inorganic salt type, solid–liquid ratio, salt concentration, pH, ultrasonic time, temperature, and volume of dimethyl carbonate was examined. Based on the single-factor tests and response surface methodology (RSM), optimal conditions were identified as 30 % ammonium citrate, a 1:26 solid–liquid ratio, pH 3, 31 min of ultrasonic time, 30 °C temperature, and 15 mL of dimethyl carbonate. These conditions achieved extraction rates of 8.10 % for lipids, 5.03 % for proteins, and 10.03 % for polysaccharides, with recovery rates of 91.62 %, 83.08 %, and 93.95 % respectively. Chemical analysis showed the lipid fraction rich in linoleic acid, and the protein fraction high in glutamic acid, aspartate, and serine. The polysaccharide fraction, mainly RG-I pectin with a molecular weight of 226.58 kDa, exhibited strong thermal stability and inhibitory effects on α-glucosidase and glycation, suggesting potential for functional food and dietary supplement applications. This highlights UTPP as a sustainable method for effectively utilizing valuable compounds from IPM cake meal, outperforming traditional extraction techniques.

Extraction of egg yolk lipids via salt-induced synergistic heat treatment: Fabrication, characterization and flavor analysis

In this study, the oxidation of egg yolk lipids (EYL) by salt-induced heat and non-heat treatments was investigated for quality and flavor. The correlation between physicochemical properties, lipid oxidation and antioxidant activity was modeled using partial least squares discriminant analysis (PLS-DA). The results indicated that the prolonged salt-induced synergistic heat treatment produced the highest level of lipid oxidation, antioxidant activity and oil exudation, along with the lowest level of polyunsaturated fatty acid content. In addition, higher contents of pyrazines and fewer acid species were detected, which was not the case with the salt-free heat treatment. In total, 14 identical volatile organic compounds (VOCs) were produced, yet their overall flavor profiles determined by the electronic nose would remain dramatically distinguished. Therefore, heat treatment was particularly critical for lipid oxidation and the generation of aromatic compounds, implying that heat-treated EYL induced by salt is a flavor component with good antioxidant potential.

Structural basis for lipid transfer by the ATG2A-ATG9A complex.

Autophagy is characterized by the formation of double-membrane vesicles called autophagosomes. Autophagy-related proteins (ATGs) 2A and 9A have an essential role in autophagy by mediating lipid transfer and re-equilibration between membranes for autophagosome formation. Here we report the cryo-electron microscopy structures of human ATG2A in complex with WD-repeat protein interacting with phosphoinositides 4 (WIPI4) at 3.2 Å and the ATG2A-WIPI4-ATG9A complex at 7 Å global resolution. On the basis of molecular dynamics simulations, we propose a mechanism of lipid extraction from the donor membranes. Our analysis revealed 3:1 stoichiometry of the ATG9A-ATG2A complex, directly aligning the ATG9A lateral pore with ATG2A lipid transfer cavity, and an interaction of the ATG9A trimer with both the N-terminal and the C-terminal tip of rod-shaped ATG2A. Cryo-electron tomography of ATG2A liposome-binding states showed that ATG2A tethers lipid vesicles at different orientations. In summary, this study provides a molecular basis for the growth of the phagophore membrane and lends structural insights into spatially coupled lipid transport and re-equilibration during autophagosome formation.

Prediction of fat content in edible insect powders using handheld FT-IR spectroscopic devices

The present study describes a new approach to predict the level of crude fat present in commercial edible Tenebrio molitor and Alphitobius diaperinus powders partially defatted using mid and near infrared spectral data combined with multivariate analysis. Insect powders were partially defatted by using three organic solvents and CO2 in supercritical conditions obtaining samples with fat content ranging from 0 to 28.7% (n = 46). Lipid content and fatty acid profile were determined by using Soxhlet and fatty acid methyl esters (FAME) methods, respectively. Spectral data was acquired using a two handheld FT-NIR devices (1350–2550 nm) and two portable FT-MIR equipment (4000-630 cm−1) equipped with ATR crystals. Partial least squares regression (PLSR) model was used to easily predict insect fat content. Ethanol had lipid extraction yields significantly lower, specially for T. molitor. FA composition was affected by the solvent used. PLSR results exhibited good linearity, predicting crude fat content with strong correlation (Rcv≥0.9) and low standard error of cross-validation (SECV = 1.06–3.22%). Nonetheless, the FT-NIR devices tested, showed higher performance for fat content prediction in insect powders, reaching values of 0.99 in coefficient of correlation (RP) and 1.05% in standard error in prediction (SEP).