Protein, lipid, and chitin fractions from insects: Method of extraction, functional properties, and potential applications.

Edible insects are accepted as food and feed ingredients in many parts of the world. Insects account for more than 80% of animal kingdom providing rich biodiversity of protein and lipid profiles compared to conventional livestock. Insect biomasses contain an average of 35-62% protein, 3-57% lipid, and 3-12% chitin, and their nutritional values are widely recognized due to their presence, including minerals, and vitamins. While whole insects are consumed as eggs, larvae, pupae, or adults, there has been a recent uptick in interest to use fractions, e.g., protein, lipid, and chitin, as food and feed ingredients. To utilize these fractions in various food and feed preparations, a deeper understanding of the physicochemical as well as functional properties of the ingredients is required, which are generally impacted by extraction and preparation processes. Thus, the methods of extraction/purification are important to preserve the quality and functional properties of these ingredients. This paper discusses the extraction methods for insect protein, lipid, and chitin, their functional properties, and potential applications in food and feed applications.

Evaluation of corn steep liquor as fermentation media for recombinant Lactococcus lactis producing antifreeze proteins.

BACKGROUND: Corn processing byproducts corn steep liquor (CSL), and thin stillage were evaluated as growth media for recombinant Lactococcus lactis modified to produce antifreeze proteins (AFPs) that could have important food and non-food applications. The AFP III sequence from ocean pout was cloned into a shuttle vector to make an expression vector that facilitated the production of recombinant AFP III in Lactococcus lactis. Light CSL from yellow dent corn and thin stillage from the industrial corn bioethanol process were optimized as fermentation media with a combination of the following additives and trace elements: disodium-ß-glycerophosphate (DG), tryptone (T), ascorbic acid (AA), iron (Fe), zinc (Zn), and magnesium (Mg). The growth of wild-type and recombinant Lactococcus lactis strains were compared over a 72 h period in 96-well plates and 250 mL shake flasks. RESULTS: The corn coproducts media consisting of 50% (v/v) light steep in water supplemented with DG-5 g L-1 , T-5 g L-1 , AA-0.5 g L-1 , and Zn-4 ppm resulted in best growth and was considered as the best-optimized media. The addition of additives and trace elements better supported the growth of both wild-type and recombinant Lactococcus lactis strains compared to control media without any additives. Respective fermentation supernatants were frozen to -20 °C, and the time to supercool and freeze was compared. A distinct supercooling effect was observed for the supernatants from recombinant strains thus, extending the time and temperature of supercooling and freezing. The maximum time of supercooling extended was 17.55 ± 4.45 min for thin stillage followed by M17 media (17.25 ± 4.45 min), Kent Corporation CSL (10.80 ± 2.12 min), and yellow dent CSL (6.9 ± 0.85 min) when fermented with recombinant Lactococcus lactis strains. CONCLUSION: The supplemented corn coproduct-based media enhanced the growth of both wild-type and recombinant Lactococcus lactis strains. These optimized media can replace or supplement more expensive media (e.g. M17), potentially reducing cost. The fermentation supernatants exhibited longer times to supercool, and freeze compared to control supernatants, indicating potential use as antifreeze compounds in frozen food and non-food applications. © 2023 The Authors. Journal of The Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

Fermentation performance and nutritional assessment of physically processed lentil and green pea flour.

BACKGROUND: Significant amounts of nutrients, including dietary fibers, proteins, minerals, and vitamins are present in legumes, but the presence of anti-nutritional factors (ANFs) like phytic acid, tannins, and enzyme inhibitors impact the consumption of legumes and nutrient availability. In this research, the effect of a physical process (sonication or precooking) and fermentation with Lactobacillus plantarum and Pediococcus acidilactici on the ANFs of some legumes was evaluated. RESULTS: Total phenolic content was significantly (P < 0.05) reduced for modified and fermented substrates compared with non-fermented controls. Trypsin inhibitory activity (TIA) was reduced significantly for all substrates except for unsonicated soybean and lentils fermented with L. plantarum and P. acidilactici. When physical processing was done, there was a decrease in TIA for all the substrate. Phytic acid content decreased for physically modified soybean and lentil but not significantly for green pea. Even though there was a decrease in ANFs, there was no significant change in in vitro protein digestibility for all substrates except for unsonicated L. plantarum fermented soybean flour and precooked L. plantarum fermented lentil. Similarly, there was a change in amino acid content when physically modified and fermented. CONCLUSION: Both modified and unmodified soybean flour, green pea flour, and lentil flour supported the growth of L. plantarum and P. acidilactici. The fermentation of this physically processed legume and pulse flours influenced the non-nutritive compounds, thereby potentially improving nutritional quality and usage. © 2021 The Authors. Journal of The Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

High-power sonication of soy proteins: Hydroxyl radicals and their effects on protein structure.

High-power sonication (HPS) is shown to alter protein structure, thus, its functionality, via intermolecular interactions. This study evaluated the effects of HPS on molecular structure of soy proteins in aqueous medium. Free radicals generated during HPS were quantitated using the 5,5-dimethyl-l-pyrrolin N-oxide (DMPO) spin trap method. Electron paramagnetic resonance (EPR) was used to identify them as mostly hydroxyl radicals. The minimum saturation concentration of spin trap solution was determined to be 500 mM of DMPO in water, when exposed to 5 W/cm3 ultrasound power density (PD) for 10 min; subsequently, this concentration was used for quantitating radicals generated in protein samples. Five aqueous soy protein systems, namely, 5% soy protein isolate (SPI), 5% SPI without isoflavonoids (NO-ISO SPI), subunit solutions 1% glycinin (11S) and 1% ß conglycinin (7S), and 10% soy flakes (w/v), were sonicated at 2.5 and 5 W/cm3 PDs. Only adducts of hydroxyl radicals (DMPO-OH) were detected in all of these aqueous systems. The highest concentration (3.68 µM) of DMPO-OH adduct was measured in 11S subunit solution at 5 W/cm3, whereas, the lowest (0.67 µM) was in soy flakes solution at 2.5 W/cm3. PD 5 W/cm3 generated higher concentration of radicals in 7S subunit solution, NO-ISO SPI, and soy flakes protein, compared to sonication at PD 2.5 W/cm3. No change in the protein electrophoretic patterns were observed due to HPS. However, some changes due to HPS were observed in the estimated secondary and tertiary structures, and the contents of free sulfhydryl groups and disulfide bonds in proteins.

Effect of high-power sonication pretreatment on extraction and some physicochemical properties of proteins from chickpea, kidney bean, and soybean.

Impact of high-power sonication (HPS) as pretreatment in extraction and some physicochemical properties of proteins from soybean flakes, flour of soybean, chickpea, and kidney bean was evaluated. Soybean flakes and flours from soybean, chickpea, and kidney bean were dispersed in distilled water (1.10 w/v) and sonicated at two power densities (PD) of 2.5 and 4.5 W/cm3 for 5 min continuously. Proteins were extracted at pH range 8-8.5. PD 2.5 and 4.5 W/cm3 significantly increased protein extraction yields from soy flakes to 29.03% and 25.87%, respectively, compared to 15.28% for unsonicated controls, but did not increase for flours. Freeze-dried spent substrates at higher PD sonication aggregated in size. Free sulfhydryl content for both sonicated and unsonicated soy flakes and flour were similar but increased in chickpea and kidney bean when HPS of 4.5 W/cm3 was applied, indicating the unfolding of protein structure. The protein band patterns for sonicated and unsonicated legumes proteins were found to be similar, indicating no peptide profile alterations by HPS. However, circular dichroism analysis showed changes in secondary structure composition in extracted kidney bean protein causing unfolding and destabilizing the native structure. The secondary structure composition for soy flakes and flour protein and chickpea protein remained unchanged.

Evaluation of α-amylase, lipase inhibition and in-vivo pharmacological activities of Eucalyptus camaladulensis Dehnh leaf extract.

In this present study, phytochemical screening, anti-ulcer assay, anti-diarrhea assay, anti-inflammatory assay, analgesic assay, lipase activity assay, amylase activity assay and the anti-bacterial activity of Eucalyptus camaladulensis Dehnh leaf extracted with methanol and 50% ethanol was analyzed for biological significance. Physical characterization of the non-volatile component revealed the higher yield of 16.92% in 50% ethanol expediting the use of 50% ethanol as a better alternative. Further use of crude extract revealed 33.89% (IC50 = 1.44 mg/ml) of α-amylase inhibition by methanol extract and 33.87% (IC50 = 3.21 mg/ml) lipase inhibition by 50% ethanol extract. Furthermore, 44.44% protective ratio towards ulcer was observed with the methanol extract, whereas 54.58% anti-inflammatory activity was shown by the 50% ethanol extract. The effectiveness of the extract was further enhanced by the presence of 62.54% motility and best analgesic property at 180 min of the exposure of the extract orally. The antioxidant activity of crude methanol extract revealed an IC50 value 601.8 µg/ml whereas, ethanol extract showed 1279.58 µg/ml in DPPH assay. Result revealed several health benefits of E. camaldulensis Dehnh leaf.