Silkworm Pupae Protein Research Articles

Silkworm pupae protein-based film incorporated with Catharanthus roseus leaf extract-based nanoparticles enhanced the lipid stability and microbial quality of cheddar cheese

The study aimed to develop a silkworm pupae protein-based film for enhancing the lipid oxidative and microbial stability of cheddar cheese. The bioactive properties were imparted to the silkworm pupae protein-based film using an optimum level (2.0%) of Catharanthus roseus leaf extract-based nanoparticles (Cat-Ros-NPs) synthesised following a green method. The cheese samples were packaged within the treated film (T2, containing 2.0% Cat-Ros-NPs) and compared with control samples [control (cheese samples without any film), T0 (cheese samples within the films without any bioactive agent) and T1 {cheese samples within the films containing 2.0% C. roseus leaf extract (Cat-Ros-Ext)}] during 90 days trial (4±1 °C). The addition of bioactive agents (Cat-Ros-Ext or Cat-Ros-NPs) increased the thickness (µm) as well as density (g/ml) of the film, thereby decreasing the transmittance (%), solubility (%), moisture content (%), and water-vapour transmission rate (mg/mt2). Both the bioactive agents increased the redness (a*) and yellowness (b*) whereas decreased the brightness (L*) of the film. The films enhanced the antioxidant and antimicrobial properties of the enclosed cheese samples during storage and the highest values were recorded for the samples packed within T2 films. The cheese samples packaged within T2 and T1 films showed significantly lower values for lipid oxidation and microbial counts. This positive effect of the films (T2 and T1) was also recorded on protein oxidation (total-carbonyl content) after day 30 and sensory quality after day 60. Our results indicate the successful use of silkworm pupae protein for the development of bioactive packaging for cheddar cheese.

The Protective Effects of Silkworm (Bombyx mori) Pupae Peptides on UV-Induced Skin Photoaging in Mice.

Silkworm (Bombyx mori) pupae are popular edible insects with high nutritional and therapeutic value. Currently, there is growing interest in the comprehensive application of silkworm pupae. In this study, peptides that exhibited anti-photoaging activity were obtained from silkworm pupae protein, aiming to investigate the protective effects and potential mechanisms of silkworm pupae peptides (SPPs) on skin photoaging. The results showed that SPPs were composed of 900 short peptides and could effectively alleviate skin photoaging progression. They significantly eliminated excessive production of ROS and MDA; meanwhile, they also renovated the antioxidant enzyme activities. The biomarkers related to collagen synthesis and degradation, including hydroxyproline, interstitial collagenase, and gelatinase, demonstrated that SPPs could suppress collagen degradation. Histopathological results showed that SPPs could reduce the inflammatory infiltrate and the thickness of the dermis and epidermis, as well as increase the collagen bundles and muscle fibers. The histopathological and biochemical results confirmed that SPPs could alleviate photoaging by inhibiting abnormal skin changes, reducing oxidative stress, and immune suppression. Overall, these data prove the protective effects of SPPs against the photoaging process, suggesting their potential as an active ingredient in skin photoaging prevention and therapy.

Silkworm pupa protein-derived peptides alleviate LPS-induced inflammatory response in RAW264.7 macrophage cells through the NF-κB/MAPK/PI3K-AKT signaling pathway

A plethora of studies have indicated that protein or peptides derived from food sources possess potential anti-inflammatory activity. In our previous research, we discovered peptides from silkworm pupae (Bombyx mori) exhibited promising anti-inflammatory effects in mice. However, the anti-inflammatory activity of silkworm pupae protein peptides (SPP) has yet to be validated at the cellular level, and its underlying anti-inflammatory mechanisms remain unclear. Therefore, the aim of this study was to explore the anti-inflammatory potential of SPP in lipopolysaccharide (LPS)-induced RAW264.7 inflammation model. Our research findings demonstrated that SPP significantly reduced LPS-induced inflammation in RAW264.7 cells in a dose-dependent manner, including decreased levels of inflammatory mediators (NO, MCP-1, and PEG2) and cytokines (TNF-α, IL-6, and IL-1β). Furthermore, we observed significant downregulation of mRNA and protein expression of iNOS and COX-2 by SPP (p < 0.05). Additionally, SPP exerted its anti-inflammatory effects by inhibiting the NF-κB/MAPK/PI3K signaling pathway. These results suggested that SPP may serve as a novel functional food ingredient for the prevention or treatment of inflammation-related diseases.

Study on the relationship between structure and moisturizing performance of seamless knitted fabrics of protein fibers for autumn and winter

Abstract With dry weather and low humidity in autumn and winter, human skin is usually prone to dryness, even leading to itchy skin and other problems, so it is important to do a good job of skin moisturizing. The fabrics produced by using protein fiber have a certain moisturizing effect on human skin. Five types of yarn including collagen fiber, cheese protein fiber, silkworm pupa protein fiber, cashmere protein fiber, and viscose are chosen as veil materials, while nylon/spandex composite fiber is chosen as inner yarn material. Three fabric structures including the weft plain stitch, 1 + 1 mock rib, and 1 + 3 mock rib are selected for the study. Based on the full factorial experimental design method, 15 samples of seamless knitted fabrics are produced using a circular knitting machine. In order to investigate the effects of different veil materials and fabric structure of seamless knitted fabric on skin moisturizing performance, the skin moisture content test and the trans-epidermal water loss test were carried out before and after the fabric samples were wrapped around the skin of 20 participants. The results show that both the veil materials and the fabric structure have significant effects on the skin moisture content. The use of collagen yarn as the veil material and 1 + 1 mock rib as the fabric structure results in better moisturizing effects on human skin. In terms of the trans-epidermal water loss test, the fabric structure has significant effects on the results, while the veil material has no significant effect on it. However, the value of trans-epidermal water loss of the fabric with protein yarn is smaller than that of the fabric with ordinary viscose. Therefore, using cheese protein yarn as the veil material and 1 + 1 mock rib as the fabric structure results in a smaller trans-epidermal water loss value.

Effect of carbonyl-amino condensation, non-covalent cross-linking and conformational changes induced by ultrasound-assisted Maillard reaction on lysinoalanine formation in silkworm pupa protein

The inhibition of cross-linked lysinoalanine (LAL) formation in silkworm pupa protein isolates (SPPI) by Maillard reaction (using varying xylose concentration) and ultrasound treatment was studied. Results showed that sonicated SPPI was effectively grafted with high concentration of xylose (5 %), resulting in the lowest LAL content, which was 48.75 % and 30.64 % lower than the control and ultrasound-treated samples, respectively. Chemical bond analysis showed that the combined treatment destroyed the ionic bonds, intrachain (g-g-t), and interchain (g-g-g) disulfide bonds, but stimulated the polymerization of hydrogen and hydrophobic bonds between SPPI and xylose, and as well enhanced the net negative charge between SPPI/Xylose complexes. The particles of the complexes were more loose, dispersed and rough, and had a stronger hydrophilic microenvironment, accompanied by alterations in microscopic, secondary and tertiary structures. Ultrasound treatment induced the breakdown of the oxidative cross-linking in SPPI, and promoted the sulfhydryl group-dehydroalanine binding and the carbonyl-amino condensation of the protein and xylose, and thus inhibited the formation of cross-linked LAL. Furthermore, the physicochemical and structural parameters were highly interrelated with cross-linked LAL content (|r| > 0.9). The outcomes provided a novel avenue and theoretical basis for minimizing LAL formation in SPPI and improving the nutrition and safety of SPPI.

Revealing the synergistic effect of hydration and pulsed ultrasound on the emulsifying properties of silkworm pupa protein and its stabilized emulsion.

Silkworm (Bombyx moil L.) Pupa protein (SPP) is a high-quality insect protein and is considered a sustainable alternative source for traditional animal food protein. However, the utilization of SPP is limited because of its low solubility and emulsifying ability. In the present study, the synergistic effect of hydration and pulsed ultrasound on the physicochemical properties of SPP and SPP-stabilized Pickering emulsions was evaluated. Pulsed ultrasound changed the particle size of SPP and its conformation. As the pulsed ultrasound increased from 0 s to 5 s, the α-helix and SS contents of SPP decreased, whereas the β-sheet and SH contents increased, which in turn improved its solubility and amphiphilicity. As a result, the SPP treated by a combination of 12 h of hydration and 3 s of ultrasound exhibited a contact angle of 74.95°, hydrophobicity of 904.83, EAI of 6.66 m2 g-1 and ESI of 190.69 min. Compared with the combination of 1 h of hydration and 5 s of ultrasound, the combination of 12 h of hydration and 3 s of ultrasound exerted more soluble and hydrophobic SPP, whereas the EAI and ESI of the samples were higher. Notably, the ultrasound-treated SPP can form a stable gel-like emulsion (oil fraction ranging from 70% to 80%). The combination of hydration and ultrasound can effectively improve the physicochemical characteristics of SPP as well as its emulsion stability. Sufficient hydration is a cost-effective method for facilitating the modification of proteins by ultrasound treatment. © 2024 Society of Chemical Industry.

Silkworm pupae protein co-degradation by magnetic nanoparticles immobilized proteinase K and Mucor circinelloides aspartic protease for further utilization of sericulture by-products

Silkworm pupae, by-product of sericulture industry, is massively discarded. The degradation rate of silkworm pupae protein is critical to further employment, which reduces the impact of waste on the environment. Herein, magnetic Janus mesoporous silica nanoparticles immobilized proteinase K mutant T206M and Mucor circinelloides aspartic protease were employed in the co-degradation. The thermostability of T206M improved by enhancing structural rigidity (t1/2 by 30 min and T50 by 5 °C), prompting the degradation efficiency. At 65 °C and pH 7, degradation rate reached the highest of 61.7%, which improved by 26% compared with single free protease degradation. Besides, the immobilized protease is easy to separate and reuse, which maintains 50% activity after 10 recycles. Therefore, immobilized protease co-degradation was first applied to the development and utilization of silkworm pupae resulting in the release of promising antioxidant properties and reduces the environmental impact by utilizing a natural and renewable resource.

Effect of Ultrasonic-Assisted Enzymatic Hydrolysis on Functional Properties and Antioxidant Activity of Eri Silkworm Pupa Protein Isolate

Philosamia ricini (Eri silkworm) pupa protein isolate (EPI) was utilized to prepare pupa protein hydrolysate (EPIH) through enzymatic hydrolysis. Additionally, the isolate underwent ultrasonic treatment at 20 kHz to become ultrasound pretreated EPI (EPIU), which was then enzymatically hydrolyzed to obtain ultrasound pretreated protein hydrolysate (EPIUH). The physicochemical properties of these samples were investigated, including molecular weight, solubility, foaming and emulsion properties, water- and oil-holding capacity, antioxidant activity, and color. When compared to EPI (used as the control), EPIU exhibited a high degree of hydrolysis at 20 minutes ( DH = 29.24 % ). At a total process time of 20 minutes, the degree of hydrolysis for EPIH, EPIU, and EPIUH was found to be 13%, 29%, and 41%, respectively. SDS-PAGE analysis indicated no difference in molecular weight between EPI and EPIU (11–75 kDa). However, the molecular weight profiles of EPIH and EPIUH were reduced (8–45 kDa), resulting in changes in protein functionalities. The high DH value contributed to the enhancement of antioxidant activity, solubility, emulsion capacity, emulsion stability, and foam capacity of the protein isolate at pH 7. Furthermore, the ultrasonic pretreatment of the protein hydrolysate increased the lightness of the protein powder by reducing the enzyme activity of the polyphenol oxidase (PPO). These results suggest that ultrasonic pretreatment of the protein hydrolysate could be applied to improve the properties of Eri silkworm pupa protein for use in the food and beverage industry, such as protein-rich beverages or salad dressings.

Inhibition of cross-linked lysinoalanine formation in pH12.5-shifted silkworm pupa protein, and functionality thereof: Effect of ultrasonication and glycation

We added three different carbohydrates (Xylose/Xyl, Maltose/Mal, and Sodium alginate/Sal) to pH12.5-shifted silkworm pupa protein isolates (SPPI), and examined the influence of multi-frequency ultrasound (US) on them, with reference to lysinoalanine (LAL) formation, changes in conformational characteristics and functionality. Results showed that, the LAL content of the glycoconjugates - SPPI-Xyl, SPPI-Mal, and SPPI-Sal decreased by 1.47, 1.39, and 1.54 times, respectively, compared with the control. Notably, ultrasonication further reduced the LAL content by 45.85 % and brought SPPI-Xyl highest graft degree (57.14 %). SPPI-Xyl and SPPI-Mal were polymerized by different non-covalent bonds, and SPPI-Sal were polymerized through ionic, hydrogen, and disulfide (covalent/non-covalent) bonds. Significant increase in turbidity, Maillard reaction products and the formation of new hydroxyl groups was detected in grafted SPPI (p < 0.05). US and glycation altered the structure and surface topography of SPPI, in which sugars with high molecular weight were more likely to aggregate with SPPI into enormous nanoparticles with high steric hindrance. Compared to control, the solubility at pH 7.0, emulsifying capacity and stability, and foaming capacity of SPPI-US-Xyl were respectively increased by 244.33 %, 86.5 %, 414.67 %, and 31.58 %. Thus, combined US and xylose-glycation could be an effective approach for minimizing LAL content and optimizing functionality of SPPI.

Silkworm pupa protein peptide improved DSS-induced colitis in C57BL/6 mice through the MAPK/NF-κB signaling pathway

Numerous studies have revealed the multifunctional activities of silkworm pupa peptides (SPP). In this study, we investigated the protective effects of SPP on dextran sulfate sodium (DSS)-induced colitis in mice. The results showed that SPP improved the clinical symptoms of colitis in mice, including increased colon length, slowed weight loss, and reduced disease activity index (DAI) scores. Furthermore, SPP significantly alleviated DSS-induced colonic injury by reducing the expression of myeloperoxidase (MPO) in colonic tissues, enhancing mucin secretion in the colon, and decreasing colonic cell apoptosis. SPP also mitigated the severity of colitis by modulating serum inflammatory factors and improving colonic oxidative stress levels. Western blot analysis revealed that SPP suppressed the activation of the MAPK and NF-κB signaling pathways. In conclusion, SPP protected against DSS-induced colitis in mice by reducing cell apoptosis, attenuating inflammatory responses, and improving oxidative stress levels, potentially through the inhibition of MAPK and NF-κB signaling pathways.

Effects of Silkworm Pupae Protein and Active Peptides on Human Immunity

The escalating global population and the concomitant scarcity of protein resources have heightened the urgency to explore novel sources of protein. Insects, as a taxonomic class of organisms, are abundantly enriched with superior-quality protein and steered by this premise, they present a prodigious opportunity for human employment and scientific investigation in the realm of biologic resources. The larval stage of the domesticated silkworms, extensively cultivated for their silk, give rise to the universally consumed pupae in East Asia that augment the dietary provisions. This paper provides a comprehensive discussion of the immune-boosting, antibacterial, antitumor, and antioxidant properties of silkworm pupae proteins. Additionally, it explores the possible allergic reactions that may arise from silkworm consumption. Silkworm chrysalis protein, which contains a plethora of bioactive peptides such as AKPGVY and AAEYPA, offers a novel source of antioxidant peptides that have been shown to bolster immune function, enhance the body's capacity to fend off bacteria and viruses, reduce the risk of tumor development, and mitigate adverse effects such as free radical oxidative damage. However, it is important to note that some individuals may be susceptible to allergic reactions to silkworm pupae. Consequently, safety concerns related to the use of silkworm pupae proteins and active peptides should be taken into account.

Limited hydrolysis combined with glycation modification of silkworm pupae (Bombyx mori) proteins: structure-function relationship

Abstract In order to explore the impacts of limited hydrolysis combined with glycation modification on the structure, functional properties, allergenicity, and volatile compounds of silkworm pupae protein, the crude silkworm pupae protein was firstly extracted by alkaline-solution method, followed by Alcalase-treated limited hydrolysis for 10-30 min. Xylose was subsequently added and reacted for 1 h at 95 °C. Afterwards, the structure, functionality, allergenicity, and volatile compounds before and after modification were analysed. The molecular weight of modified silkworm pupae protein was remarkably decreased. The solubility was improved from 4.7 to 28.6%. The foaming ability was elevated by 21%. The in vitro digestibility was elevated by 34.0-44.4%. Furthermore, the abundance of six potential allergic proteins was remarkably reduced. In addition, the contents of off-flavour compounds in modified silkworm pupae proteins substantially decreased. Overall, limited hydrolysis combined with glycation modification can improve the functionality and flavour of silkworm pupae protein, while reduce the allergenicity.

Effects of Protein Hydrolysate from Silkworm (Bombyx mori) pupae on the C2C12 Myogenic Differentiation.

This study investigated the effects and active compounds of silkworm pupae, an edible insect, on C2C12 muscle differentiation. The protein of silkworm pupae was extracted using sonication after defatting with hexane. Subsequently, the extract was rehydrated using Alcalase to obtain a protein hydrolysate. The silkworm pupae protein hydrolysate effectively promoted C2C12 myogenic differentiation without cytotoxicity. Subsequently, the hydrolysate was fractionated into four subfractions using preparative high-performance liquid chromatography (Prep-HPLC). Subfraction 1 was the most effective in promoting C2C12 myogenic differentiation and significantly upregulated the expression of myoblast transcription factors, 1.5-fold of myoblast determination protein 1 (MyoD), 2-fold of myogenin, and 3-fold of myosin heavy chain (MyHC). Liquid chromatography-tandem mass spectrometry (LC-MS/MS) and multivariate statistical analysis were used to identify the active peptides in silkworm pupae responsible for the observed effects; then, dipeptides and essential amino acids, such as isoleucine (Ile), valine (Val), and methionine (Met), were identified. In addition, Val, Ile, and two dipeptides underwent quantification to determine the potential bioactive peptides that enhanced C2C12 myogenic differentiation. This study suggests that the peptides from silkworm pupae could be used as a nutraceutical to enhance muscle growth.

Effect of silkworm pupae (Bombyx mori) protein on colon cancer in nude mice: inhibition of tumor growth, oxidative stress and inflammatory response.

Silkworm pupa (bombyx mori) protein (SPP) is a potential therapeutic bioactive substance that has anti-tumor activity against breast, liver, and gastric cancers. The aim of this study was to investigate the antitumor effect of SPP on colon cancer nude mice. Using a subcutaneous tumor formation method, we validated the therapeutic effect of SPP on colon cancer nude mice in vivo. Results showed that SPP was cytotoxic to tumor cells. SPP could protect the liver of the nude mice by lowering hepatic oxidative stress and regulating serum inflammation levels by decreasing TNF-α and IL-2 levels while in-creasing INF-γ levels. In addition, diminished Ki-67 protein, enhanced cleaved caspase-3 protein, di-minished Vimentin, enhanced E-cadherin. These findings suggested that SPP's antitumor activity may be achieved by reducing inflammation, inhibiting tumor proliferation and metastasis, and inducing apoptosis in cancer cells. In the future, SPP could be used as an anticancer drug, potentially providing a new source of drugs for the treatment of colon cancer.

Intestine-targeted high internal phase Pickering emulsion formulated using silkworm pupa protein via ultrasonic treatment

High internal phase Pickering emulsions (HIPPEs) stabilized by food grade particles have received much attention as deliver vehicles for bioactives in recent years. In this study, ultrasonic treatment was conducted to regulate the size of silkworm pupa protein (SPP) particles, fabricating oil–in–water (O/W) HIPPEs with intestinal releasability. Briefly, the pretreated SPP and SPP-stabilized HIPPEs were characterized, and the targeting release was investigated using in vitro gastrointestinal simulations and sodium dodecyl sulfate–polyacrylamide gel electrophoresis. Results revealed ultrasonic treatment time was the key factor regulating emulsification performance and stability of HIPPEs. Optimized SPP particles were obtained based on their size and zeta potential of 152.67 nm and 26.77 mV, respectively. With ultrasonic treatment, the hydrophobic groups in the secondary structure of SPP were exposed, facilitating the formation of a stable oil–water interface for HIPPEs. Additionally, SPP-stabilized HIPPE showed high stable against the gastric digestion. The SPP with 70 kDa molecular weight, which was the major interfacial proteins of the HIPPE, can be hydrolyzed by intestinal digestive enzymes, enabling the intestine-targeted release of the emulsion. Overall, in the present study, a facile method was developed to stabilize HIPPEs using solo SPP with ultrasonic treatment to protect and deliver hydrophobic bioactive ingredients.

Characteristics of enzymolysis of silkworm pupa protein after tri-frequency ultrasonic pretreatment: kinetics, thermodynamics, structure and antioxidant changes.

As a by-product of the sericulture industry, the utilization rate of silkworm pupa resources is currently not high. Proteins are converted into bioactive peptides through enzymatic hydrolysis. Not only can it solve the utilization problem, but it also creates more valuable nutritional additives. Silkworm pupa protein (SPP) was pretreated with tri-frequency ultrasonic (22/28/40kHz). Effects of ultrasonic pretreatment on enzymolysis kinetics, enzymolysis thermodynamics, hydrolysate structure as well as hydrolysate antioxidant of SPP were investigated. Ultrasonic pretreatment significantly increased the hydrolysis efficiency, showing a 6.369% decrease in k m and a 16.746% increase in k A after ultrasonic action (p < 0.05). The SPP enzymolysis reaction followed a second-order rate kinetics model. Evaluation of enzymolysis thermodynamics revealed that Ultrasonic pretreatment markedly enhanced the SPP enzymolysis, leading to a 21.943% decrease in E a. Besides, Ultrasonic pretreatment significantly increased SPP hydrolysate's surface hydrophobicity, thermal stability, crystallinity, and antioxidant activities (DPPH radical scavenging activity, Fe2+ chelation ability, and reducing power). This study indicated that tri-frequency ultrasonic pretreatment could be an efficient approach to enhancing the enzymolysis and improving the functional properties of SPP. Therefore, tri-frequency ultrasound technology can be applied industrially to enhance enzyme reaction process.

Valorization of the insect waste as a source of dietary protein in replacing the fishmeal protein for the cage reared Pangasianodon hypophthalmus: An approach to search the alternate non-conventional feed resource of animal origin

A ninety days experiment was carried-out to evaluate the effect of dietary replacement of fishmeal (FM) (locally available dried non-defatted Coilia dussumieri V.) by graded inclusion levels of non-defatted non-mulberry Indian tropical tasar silkworm spent pupae (Antheraea mylitta D.) on growth performance, feed consumption, digestive enzyme response, body chemical composition, and intestinal cellular micro-morphological status of the reared striped catfish (Pangasianodon hypophthalmus S.). Five iso-nitrogenous (280 g protein kg-1) and iso-energic (19 MJ kg-1) extruded floating feeds were formulated by gradually replacing the FM with NDSWP (non-defatted silkworm pupae) at 0%, 25%, 50%, 75%, and 100% (on protein to protein basis) levels and the diets are designated as NDSWP0, NDSWP25, NDSWP50, NDSWP75, and NDSWP100, respectively. The contribution of calculated pupae crude protein was 0%, 4.75%, 9.50%, 14.25%, and 19% out of the total protein (28%) content in the respective diets. The experiment was executed in the floating net-cage located at the Maithon reservoir, India which is a field research station of ICAR-CIFRI, Barrackpore, Kolkata, India. The designated diets were randomly allocated to 10 numbers of experimental cages (each 5 ×5 ×3 m), in triplicates stocked with 2475 numbers (stocking density at 33 numbers per m3) of striped catfish in each replication and fed daily twice at 08.00 h and 16.00 h. The initial stocking size of the striped catfish fingerling was 16.56 ± 0.08 g. At the termination of the feeding experiment, the final body weight (g), individual weight gain (g), weight gained (%), feed conversion ratio (FCR), specific growth rate (SGR), and protein efficiency ratio (PER) found to be non-significantly different (p < 0.05) up to 50% protein replacement level (NDSWP50) in comparison to the control (NDSWP0). Among the biological indices, hepatosomatic index (HSI) exhibited a non-significant difference stretching to NDSWP50 treatment group with a distinct significant difference between NDSWP25 and NDSWP100 (p < 0.05), when, an inverse trend was recorded in relation to increasing pupae meal in the diets. Among the digestive enzymes, relatively higher protease enzyme activity was observed in the diet fed at NDSWP50 compared to the rest of the treatment groups, although, it was statistically non-significant (p > 0.05). Amylase and lipase enzyme activities recorded a significant difference among the treatment groups (p < 0.05). A higher amount of fish muscle crude protein was noticed in the NDSWP50 treated group than in the rest of the treatment groups. The lipid content of fish muscle indicated its higher content over the initial and exhibited an inverse relationship with moisture and ash content at the end of the experiment. Histo-morphology of gut tissue confirms the suitability of feeding pupae protein incorporated diet with the gradual replacement of fishmeal protein. The findings of the current feeding trial suggests that the inclusion of non-defatted non-mulberry silkworm pupae protein at 50% level of fishmeal protein substitution without compromising the growth performance, nutrient utilization, conversion of feed, and other biological indices, and economics of diet.

One positive part of copper ion on biocatalysts: CNPs@Cu-Trypsin-assisted aqueous extraction technique for simultaneous exploration of edible insect oil and protein

Edible insects are rich in oil and protein resources, and has it become increasingly important to develop them reasonably when resources are increasingly scarce. However, due to the challenges in recovering enzymes in the enzyme-assisted aqueous extraction technique and the remaining organic solvents in the extraction process based on organic solvent, it is difficult to achieve simultaneous utilization of oil and protein from edible insects. Hence, an improved enzyme-assisted aqueous extraction process based on the assistance of chitosan cross-linked Fe3O4 nanoparticles (CNPs) immobilized enzymes and divalent copper ions chelation, CNPs@Cu-Trypsin-assisted aqueous extraction technique, was first proposed. The hydrolysis activity was significantly increased by 6.16 times, and the value of Kcat/Km was increased by 1.7 times for the results of the formation of the hydrophilic microenvironment. Furthermore, the extraction ratio of silkworm pupae oil extracted via CNPs@Cu-Trypsin-assisted aqueous extraction technique could be increased to 93%, and the oil extraction rate could be maintained above 65% after 10 times reused. Improvement of enzyme-assisted aqueous extraction under the addition of divalent copper ions could achieve an ideal effect of oil extracted from silkworm pupae with less time. Additionally, the quality of silkworm pupae oil was significantly improved and the silkworm pupae protein hydrolysate also showed improved biological activity. Therefore, the enzyme-assisted aqueous extraction enhancement by trypsin immobilization and divalent copper ion chelation is a promising strategy for the green and sustainable exploration of edible insect oil and protein without the use of organic solvents.

A Novel Low Molecule Peptides-calcium Chelate from Silkworm Pupae Protein Hydrolysate: Preparation, Antioxidant Activity, and Bioavailability.

The antioxidant properties of active peptides from silkworm pupae protein hydrolysate are of interest, and it serves as a novel source of calcium supplement. Optimize the preparation parameters of silkworm pupae bioactive peptide-calcium chelate, and investigate the mechanism and bioavailability of silkworm pupae active peptide as a transport carrier to promote calcium ion absorption using simulated gastrointestinal digestion and Caco-2 monolayer cell model. The optimal process parameters for preparing peptide calcium chelate were the peptide calcium mass ratio of 3:1, pH of 6.7, a temperature of 35.6°C, and time of 32.8 min by Box-Behnken design, and the calciumchelating rate reached 84.67%. The DPPH radical scavenging activity of silkworm pupae protein hydrolysatecalcium chelate was 79.36 ± 4.31%, significantly higher than silkworm pupae protein hydrolysate (61.00 ± 9.56%). Fourier transform infrared spectroscopy shows that the COO-, N-H, C-H, and C-O groups participated in the formation of silkworm pupae protein hydrolysate-calcium chelate. The particle size of the silkworm pupae protein hydrolysate-calcium chelate was 970.75 ± 30.12 nm, which was significantly higher than that of silkworm pupae protein hydrolysate (253.14 ± 5.72 nm). The silkworm pupae protein hydrolysate-calcium chelate showed a calcium dissolution rate of 71.01 ± 1.91% in the simulated intestinal phase, significantly higher than that of CaCl2 (59.34 ± 1.24%). In the Caco-2 cell monolayers, the silkworm pupae protein hydrolysatecalcium chelate was more favorable for calcium transport. A novel silkworm pupa protein hydrolysate-calcium chelate with high antioxidant activity was successfully prepared to improve the bioavailability of calcium.

Synergistic effects of pH shift and heat treatment on solubility, physicochemical and structural properties, and lysinoalanine formation in silkworm pupa protein isolates

The application of silkworm pupa protein isolates (SPPI) in food industry was limited because SPPI’s solubility is poor and it contains a potential harmful component of lysinoalanine (LAL) which formed during protein extraction. In this study, combined treatments of pH shift and heating were performed to improve the solubility of SPPI and to reduce the content of LAL. The experimental results showed that the promoting effect on SPPI’s solubility by alkaline pH shift + heat treatment was greater than that by acidic pH shift + heat. And an 8.62 times increase of solubility was observed after pH 12.5 + 80 ℃ treatment compared to the control SPPI sample which was extracted at pH 9.0 without pH shift treatment. Very strong positive correlation was found between alkali dosage and SPPI solubility (Pearson’s correlation coefficient r = 0.938). SPPI with pH 12.5 shift treatment showed the highest thermal stability. Alkaline pH shift combined with heat treatment altered the micromorphology of SPPI and destroyed the disulfide bonds between macromolecular subunits (72 and 95 kDa), resulting in reduced particle size and increased zeta potential and free sulfhydryl content of the isolates. The fluorescence spectra analysis showed red shifts phenomena with pH increasing and fluorescence intensity increase with temperature increasing, implying the alterations in the tertiary structure of protein. Compared to the control SPPI sample, the amount of LAL reduced by 47.40 %, 50.36 % and 52.39 % using pH 12.5 + 70 ℃, pH 12.5 + 80 ℃ and pH 12.5 + 90 ℃ treatment, respectively. These findings provide fundamental information for the development and application of SPPI in food industry.