Soy Protein Research Articles

A life cycle assessment of protein production from wheatgrass: Optimization potential of a novel vertical farming system

The global protein demand is expected to keep increasing due to a growing global population, combined with changing social demography and other factors. OrbiPlant®, a novel vertical farming technology developed in Germany, is used to cultivate wheatgrass (Triticum aestivum) as one possible solution for realizing a sustainable protein supply to meet this challenge. The objective of this study was to investigate the environmental impacts of wheatgrass protein concentrate powder produced in the novel vertical farming system and compare it with traditional protein sources (cheese and soy protein). To achieve this, a ‘cradle-to-gate’ life cycle assessment (LCA) was performed using OpenLCA software and Environment Footprint 3.1 method. The results show that wheatgrass protein from vertical farming has lower environmental impacts than cheese protein in terms of terrestrial eutrophication, and land use, similar impacts on freshwater ecotoxicity and particulate matter, but higher impacts in other categories. Due to the high environmental impact of the current Germany electricity mix, the overall environmental performance of wheatgrass protein remains non-competitive to traditional protein sources. By optimizing production, the environmental impact can be reduced to just 57.8 % of the cheese protein. This finding highlights the potential of the investigated wheatgrass protein from vertical farming system to reduce environmental impacts when substituting animal-based protein. Furthermore, it emphasizes the importance of utilizing renewable energy sources.

Comparative efficacy of amino acid availability and peptidomic analysis of alternative proteins from different sources under dynamic in vitro protein digestion

The increasing global demand for animal protein highlights the critical necessity of exploring alternative protein sources. Accessing the nutritional characteristics of emerging alternative proteins is vital for food processing and consumer acceptance. This study investigated the amino acid availability and peptidomics profiles of plant- (soy), fungal- (filamentous fungus Fusarium venenatum), microalgae- (Nannochloropsis oculata), and insect-based (black soldier fly) proteins using an advanced dynamic in vitro digestion system, with whey protein as a reference. After gastric digestion, soy and mycelial proteins, despite displaying distinct microstructures, exhibited slightly higher protein digestibility levels of 28.79% and 26.36%, respectively, compared to whey protein (22.39%). However, following small intestinal digestion, whey protein (61.31%) significantly outperformed alternative proteins. Mycelial protein (43.71%) exhibited digestibility similar to soy protein (46.12%), markedly surpassing both microalgae protein (33.35%) and insect protein (26.58%). Notably, insect protein achieved an amino acid availability nearly approaching that of whey protein, underscoring its substantial proteolysis capability. Furthermore, microalgae protein produced the highest percentage and number of bioactive peptides under simulated digestion, suggesting potential health benefits such as angiotensin I-converting enzyme (ACE) and dipeptidyl peptidase-IV (DPP-IV) inhibitor activities, which could mitigate the risk of hypertension and Type 2 diabetes. Alternative proteins from different sources demonstrate diverse digestive mechanisms and proteolysis profiles, thereby bolstering their potential applications as nutritious food ingredients in the future.

Soy protein processing impacts the ice recrystallization inhibition activity of protein hydrolysates

Soy protein processing impacts the ice recrystallization inhibition activity of protein hydrolysates

Full-fat black soldier fly larvae meal and yellow mealworm meal: Impact on feed protein quality, growth and nutrient utilization of Atlantic salmon (Salmo salar) post smolts

The shift towards insect-based alternatives in aquafeeds stems from the need to reduce the carbon footprint associated with the ingredients used in salmon feeds. In the present study, we describe the effects of full-fat insect meal incorporation on amino acid derivatives in feeds and the growth performance and nutrient utilization of Atlantic salmon post-smolts fed insect meals. A 74-day growth trial was conducted employing 520 fish (143 ± 12.8 g); these fish were fed either a control diet (CO) that contained 20 % fishmeal, 20 % soy protein concentrate (SPC), 14 % wheat gluten, 19 % plant raw materials, 13 % fish oil and 6 % rapeseed oil, or one of four insect meal diets, prepared with either 5 % and 10 % black soldier fly larvae meal (BS5, BS10) or 15 % and 30 % mealworm meal (MW15, MW30), by substituting mainly SPC, wheat gluten and rapeseed oil. The inclusion levels of BS and MW were determined based on their distinct chemical compositions, specifically their lipid content. As regards the results, HPLC-based high-throughput data on amino acid derivatives revealed the following: carboxymethyllysine was significantly higher in the MW30 feed than in BS5, BS10 and MW15 feeds; carboxyethyllysine was higher in the MW15 and MW30 feeds compared to the others; furosine was lower in the MW15 feed compared to the CO, BS5 and MW30 feeds. Regarding the effect of the insect meals on Atlantic salmon post-smolts, their inclusion had no significant effect on feed conversion ratio, health indicators and the retention efficiency of macronutrients. Apparent digestibility coefficients (ADC) of dry matter, lipid, ash and energy were not significantly different. However, protein digestibility in the 30 % MW group (80.4 %) was significantly lower (P ≤ 0.05) compared to the control and BS5 group (84.5 %). Furthermore, the ADC of protein was found to decrease linearly with increasing levels of insect meals, with MW showing a significant relationship (adjusted r2 = 0.77, p = 0.014). Overall, our study highlights the efficacy of 5 and 10 % BS and 15 % MW as ingredients in the feeds of Atlantic salmon. Other focal points included the undesirable amino acid derivatives and a reduction in protein digestibility associated with 30 % of MW in the diet of Atlantic salmon. Hence, future investigations should focus on the effects of feed processing conditions on the protein quality of mealworm before suggesting higher inclusion levels to the feed industry.

Formation of thermal-induced microgels from soy protein hydrolysates: Effects of selective proteolysis on glycinin/β-conglycinin

This study explored the impact of selective proteolysis on the formation of thermally induced soy protein microgels. Glycinin hydrolysate (GH) and β-conglycinin hydrolysate (CH) were obtained by subjecting soy protein isolate to selective proteolysis for different hydrolysis time (10–90 min), as confirmed by SDS-PAGE. In the early stages of hydrolysis, free sulfhydryl, surface hydrophobicity, storage modulus (G′) and loss modulus (G″) of GH and CH increased, which enhanced their gelling potential. However, as hydrolysis time increased, the gel properties of the hydrolysates progressively weakened. Structural characterization of microgels revealed that GH yielded microgels with smaller particle sizes and coarser and relatively dispersed granular structures, while CH resulted in microgels with lower potential values, smoother surfaces, and lumps resembling strand-like formations. Analysis of the structure and intermolecular force of microgels showed that the microgel formed by the GH gradually tended to be disordered, whereas the secondary structure of microgels formed by CH showed lower random coil content, resulting in a dense gel network aggregated through disulfide bonding, hydrophobic interactions and hydrogen bonding as demonstrated by frequency-dependent storage moduli measurements. Overall, this study presents a thorough characterization of microgels and shows that they can be tailored by selective proteolysis, which enables controlling the β-conglycinin/glycinin ratio of soy protein.

Analysis of the effect of lactobacillus exopolysaccharide on the rheological properties of fermented soybean protein gel: Using acid-induced soybean protein as the model

In order to accurately describe the contribution of extracellular polysaccharide (EPS) to the rheological properties of the gel in the complex system induced by lactic acid bacteria fermentation, acid-induced soy protein isolate (SPI) was used as the model. The effect of exopolysaccharide produced by Lactobacillus casei (CEPS) on the macro rheological properties and microstructural changes of acid-induced SPI gel were analyzed by scaling model and image analyses. The estimated value of storage modulus (G′) at time infinity, gel point, G′ at 37 °C, enhancement effect of G′ during cooling (ΔG'), recovery rate, critical strain (γc) and fractal dimension (Df) exhibited strong CEPS concentration dependence. The addition of CEPS led to the formation of uniform and compact three-dimensional network, which was mainly represented by small voids and apertures. Therefore, by reducing the complexity of the fermentation gel system, this study explored the effect of CEPS on the rheological properties of fermented soy protein gels and the fermented soybean protein gel with good rheological properties can be selected by quantitative image analysis.

The effect of whey/soy protein fibril systems on the properties of fish gelatin stabilized emulsion gels

In this study, we investigated the effects of whey protein isolate fibril systems (WPF) and soy protein isolate fibril systems (SPF) combined with fish gelatin (FG) on the formation of emulsion gels. The aim was to evaluate how the origin and concentration of these fibril systems influence the structural, interfacial, and rheological properties of FG-stabilized emulsion gels, as well as their impact on creaming stability. FG was mixed with varying concentrations (0–2%) of WPF and SPF at pH 7, forming electrostatic complexes due to the opposite charge interactions between FG and the protein fibril dispersions. The results revealed that adding WPF and SPF increased surface hydrophobicity and enhanced interfacial activity. Increasing WPF concentrations led to a gradual decrease in emulsion droplet size owing to the increased absorbed protein content at the interface. Additionally, there was a significant improvement in the storage modulus of the emulsion gels. Conversely, introducing a small amount (0.1%) of SPF to FG increased the particle size, suggesting potential coalescence, but further increases in SPF concentration considerably reduced the particle size. Furthermore, SPF enhanced the viscoelasticity at lower concentrations, possibly due to a more uniform distribution within the continuous phase. However, excess SPF reduced the storage modulus of the emulsion gels. Our study provides valuable theoretical insights for the application of protein fibril systems in emulsion gel systems.

Tannic acid-reinforced soy protein/oxidized tragacanth gum-based multifunctional hemostatic film for regulation of wound healing

With recent advances in the field of tissue engineering, composite films with biocompatibility, antimicrobial properties, and wound healing properties have gained potential applications in the field of wound dressings. In this research work, composite films of soy protein (S)/oxidized tragacanth gum (G) were successfully made using the solution casting process. The metal-organic framework containing curcumin (MOF) with concentrations of 5 and 10 wt% and tannic acid (TA) with concentrations of 6 and 12 wt% were entered into the polymer film. Surface morphology with scanning electron microscope (FE-SEM), thermal stability, mechanical properties, chemical structure, antioxidant, water absorption, cell viability, antibacterial activity, and biodegradability of the prepared films were investigated in laboratory conditions. In addition, the toxicity of the films in the cell environment was investigated, and the results showed that cell growth and proliferation improved in the presence of the prepared films, especially films SG/MOF10/TA6 and SG/MOF10/TA12 due to the presence of TA and MOF containing curcumin. Also, the antibacterial activity of the films showed that the presence of tannic acid and curcumin in the structure of the films increases their ability against pathogens. According to the obtained results, the newly produced nanocomposite film (SG/MOF10/TA12) has a high potential to be used for wound dressing due to its favorable characteristics and was considered the optimal film.

Incorporating κ-carrageenan regulates the gel properties and structural characteristics of corn starch-soy protein isolate based ternary system

A thorough understanding of the interactions in the starch-protein-polysaccharide ternary system is essential for the development of highly stable hydrogel systems. In this work, the effects of different κ-carrageenan (KC) incorporation on the structure and sol-gel performance of the corn starch (CS)-soy protein isolate (SPI) composite system were investigated. As the KC incorporation was raised, the gelatinization temperature increased gradually, but the enthalpy value was reduced (lower system stability, from 9.14 J/g to 8.06 J/g). The structural results show that the higher content of KC decreased the smoothness of the network structure, increased the denseness of the ternary system, and hindered the formation of nanostructures and short-range ordered structures. However, the textural properties (hardness, chewiness, gumminess) and gel strength of the composite gels increased significantly with increasing KC content (from 65.53 g to 181.90 g). This could be due to the enhancement of hydrogen bonding between KC and amylose during the cooling process, forming more stable three-dimensional network structure. This work contributes to the design of multivariate starch-based gel foods.

Comparison of in vitro digestive characteristics of proteins from different sources in simulated elderly gastrointestinal conditions

This study aimed to evaluate the impact of in vitro digestive characteristics of five different protein sources (fish, crab, beef, chicken, and soy) in adults and elderly individuals. Simulated gastrointestinal tract degradation in the elderly significantly reduced the digestibility of all proteins. The Elderly model had difficulties digesting any protein that had a firm structure or was prone to aggregation. Of the five protein types, soy protein was the least easily digested. Ultraviolet spectroscopy and SDS-PAGE analysis revealed that beef and crab proteins contain myoglobin and hemocyanin, respectively, making their structure firm. Simultaneously, alkali-soluble proteins in meat were more likely to be digested by the elderly than salt-soluble proteins. The alkali-soluble protein percentage in fish protein was the highest, including the best in vitro digestion characteristics in the elderly population. This study provides novel and significant recommendations for the elderly's daily intake of various protein sources.

Investigation of transglutaminase incubated condition on crosslink and rheological properties of soy protein isolate, and their effects in plant-based patty application

Investigation of transglutaminase incubated condition on crosslink and rheological properties of soy protein isolate, and their effects in plant-based patty application

Thermal-induced interactions between soy protein isolate and malondialdehyde: Effects on protein digestibility, structure, and formation of advanced lipoxidation end products

Thermally processed lipid- and protein-rich foods have sparked widespread concern since they may degrade food nutrition and even risk food safety. This study investigated soy protein isolate (SPI) alterations of digestibility and structure, as well as the formation of potentially hazardous chemicals, i.e., advanced lipoxidation end products (ALEs), after interacting with malondialdehyde (MDA, a lipid oxidation product) under high-temperature cooking conditions (100–180 °C, up to 60 min). In-vitro protein digestion of the SPI-MDA mixtures suggested that their room-temperature interactions damaged SPI digestibility, and increasing the temperature and the duration of the thermal treatment exacerbated the adverse effects. Protein oxidation, covalent aggregation of subunits, and changes in secondary and tertiary structures were revealed using thiol quantification, gel electrophoresis, fluorescence spectroscopy, and circular dichroism (CD) spectra, which could explain reduced protein digestibility. High-resolution mass spectrometry (HRMS) identified seven non-crosslinked ALEs and two crosslinked ALEs. Increased MDA concentrations promoted the generation of ALEs. Moreover, the acrolein-derived ALEs with reactive carbonyl groups were prone to further reacting into crosslinked ALEs, potentially responsible for the subunit aggregation.

Effects of Soy Protein Isolate and Inulin Conjugate on Gel Properties and Molecular Conformation of Spanish Mackerel Myofibrillar Protein.

The gel properties and molecular conformation of Spanish mackerel myofibrillar protein (MP) induced by soy protein isolate-inulin conjugates (SPI-inulin conjugates) were investigated. The addition of SPI-inulin conjugates significantly enhanced the quality of the protein gel. An analysis of different additives was conducted to assess their impact on the gel strength, texture, water-holding capacity (WHC), water distribution, intermolecular force, dynamic rheology, Raman spectrum, fluorescence spectrum, and microstructure of MP. The results demonstrated a substantial improvement in the strength and water retention of the MP gel with the addition of the conjugate. Compared with the control group (MP), the gel strength increased from 35.18 g·cm to 41.90 g·cm, and WHC increased from 36.80% to 52.67% with the inclusion of SPI-inulin conjugates. The hydrogen bond content was notably higher than that of other groups, and hydrophobic interaction increased from 29.30% to 36.85% with the addition of SPI-inulin conjugates. Furthermore, the addition of the conjugate altered the secondary structure of the myofibrillar gel, with a decrease in α-helix content from 62.91% to 48.42% and an increase in β-sheet content from 13.40% to 24.65%. Additionally, the SPI-inulin conjugates led to a significant reduction in the endogenous fluorescence intensity of MP. Atomic force microscopy (AFM) results revealed a substantial increase in the Rq value from 8.21 nm to 20.21 nm. Adding SPI and inulin in the form of conjugates is an effective method to improve the gel properties of proteins, which provides important guidance for the study of adding conjugates to surimi products. It has potential application prospects in commercial surimi products.

Improved encapsulation efficiency and storage stability of lutein by soy protein isolate nanocarriers with thermal and trypsin treatments.

Encapsulation of bioactive compounds within protein-based nanoparticles has garnered considerable attention in the food and pharmaceutical industries because of its potential to enhance stability and delivery. Soy protein isolate (SPI) has emerged as a promising candidate, prompting the present study aiming to modify its properties through controlled thermal and trypsin treatments for improved encapsulation efficiency (EE) of lutein and its storage stability. The EE of lutein nanoparticles encapsulated using SPI trypsin hydrolysates (SPIT) with three varying degrees of hydrolysis (4.11%, 6.91% and 10.61% for SPIT1, SPIT2 and SPIT3, respectively) increased by 12.00%, 15.78% and 18.59%, respectively, compared to SPI. Additionally, the photostability of SPIT2 showed a remarkable increase of 38.21% compared to SPI. The superior encapsulation efficiency and photostability of SPIT2 was attributed to increased exposure of hydrophobic groups, excellent antioxidant activity and uniform particle stability, despite exhibiting lower binding affinity to lutein compared to SPI. Furthermore, in SPIT2, the protein structure unfolded, with minimal impact on overall secondary structure upon lutein addition. The precise application of controlled thermal and trypsin treatments to SPI has been shown to effectively produce protein nanoparticles with substantially improved encapsulation efficiency for lutein and enhanced storage stability of the encapsulated lutein. These findings underscore the potential of controlled thermal and trypsin treatments to modify protein properties effectively and offer significant opportunities for expanding the applications of protein-based formulations across diverse fields. © 2024 Society of Chemical Industry.

375 The effects of protease supplementation on weaned piglet performance and intestinal function fed greater amounts of lower digestible protein sources

Abstract The present study investigated the impact of dietary protease supplementation on the growth performance and intestinal function of weaned piglets when fed a diet comprising high levels of low digestible protein sources, in comparison with a standard commercially representative piglet diet. A total of 180 weaned piglets, 21 d old, of Duroc × Large White × Landrace crossbreeds, with an initial body weight (BW) of 6.27 ± 0.45 kg, were randomly assigned to three dietary treatments: 1) a standard commercial positive control (PC) diet comprising 22.2% soy protein, 5% whey protein, and 3% fish meal, 2) a negative control (NC) diet comprising 30.1% soy protein without whey protein and fish meal, and 3) a NC diet supplemented with 0.02% protease (NC + PROT). The diets were formulated to be iso-nitrogenous and iso-caloric and were pelleted at conditions of 0.4 MPa and 75°C. The experimental design employed a completely randomized design with 6 replicate pens per treatment, each pen containing 10 piglets. Statistical analysis was conducted using one-way ANOVA, with differences between means assessed using Duncan’s Multiple Range Test (P < 0.05). In terms of piglet performance, feeding the NC diet, containing high levels of low digestible protein sources, resulted in a significant decrease (P < 0.05) in final BW, average daily gain (ADG), and average daily feed intake (ADFI) by 3.1%, 8.2%, and 5.2%, respectively, compared with piglets fed the PC diet. Conversely, the NC diet significantly increased (P < 0.05) the feed-to-gain ratio and incidence of diarrhea by 3.4% and 88.3%, respectively, relative to PC. However, the supplementation of protease in the NC + PROT diet restored final BW, feed-to-gain ratio, and incidence of diarrhea to the same level as PC, while ADG and ADFI were increased (P < 0.05) by 4.6% and 4.3%, respectively. Regarding intestinal function, relative to PC, piglets fed the NC diet exhibited significantly less (P < 0.05) duodenal villus height, crude protein digestibility, and gene expressions of duodenal peptide transporter PepT1 and jejunal amino acid transporter b0,+AT, while blood urea nitrogen and diamine oxidase concentrations were greater (P < 0.05). However, the addition of protease in the NC diet reinstated measures of intestinal function, as NC + PROT-fed piglets showed similar duodenal villus height, crude protein digestibility, gene expressions of duodenal peptide transporter PepT1 and jejunal amino acid transporter b0,+AT, as well as blood urea nitrogen and diamine oxidase concentrations to PC. In conclusion, dietary supplementation of protease in weaned piglets fed higher levels of lower digestible protein sources mitigated losses in growth performance and intestinal functionality by enhancing intestinal development, protein digestibility, nutrient transport efficiency, and overall health status of piglets.

Effect of N-ethylmaleimide as a blocker of disulfide bonds formation on the properties of different protein-emulsion MP composite gels

Three different emulsions of myofibrillar protein (MP), soy protein isolate (SPI) and egg white protein isolate (EPI) were individually mixed with MP sol to form composite gels. N-ethylmaleimide (NEM) was used as a sulfhydryl group blocker to evaluate the effects of sulfhydryl and disulfide bonds on the properties of different protein–emulsion composite gels. The results show that the disulfide bond contents in the MP (SPI, EPI) emulsion composite gel decreased from the initial 2.4 ± 0.1, (2.3 ± 0.2, 1.8 ± 0.4) mol/kg to 0.6 ± 0.1, (0.5 ± 0.3, 0.7 ± 0.1) mol/kg with the NEM content increased. In addition, the microstructure showed that the interfacial protein membrane of the emulsion globules were broken in different degrees, indicating that the interaction between the emulsion and the gel matrix was weakened. Meanwhile, gel strength, water distribution and elastic modulus of the composite gels were reduced with NEM contents increased.

A novel approach to produce soy protein isolate: Direct enzymatic hydrolysis of high-temperature soybean meal using proteinase produced by microbial solid-state fermentation

This study proposed a novel extraction method for soy protein isolate, which involved solid-state fermentation of high-temperature soybean meal. The proteinases secreted by microorganisms acted on the high-temperature soybean meal, making the SPI easier to extract. The study concludes that Bacillus amyloliquefaciens subsp. plantarum CICC 10265 could be used for solid-state fermentation of soybean meal, and the fermentation effect was good, with a yield of 41.91 % for SPI. Compared to the direct extraction of SPI from high-temperature soybean meal, the yield had increased by 130.19 %. Meanwhile, we also conducted research on the losses during the SPI extraction process. Through experiments, the study identified the patterns of protease activity changes and microbial colony growth during solid-state fermentation of soybean meal by Bacillus amyloliquefaciens subsp. plantarum CICC 10265. It was concluded that extracting SPI after 8 h of fermentation is more suitable. The experimental results indicated that the total amino acid content of SPI extracted from fermented soybean meal was 2.1 % higher compared to SPI extracted from low-temperature soybean meal. The extracted SPI also met the microbial standards.

Comparative study of interaction and complex formation of Tremella fuciformis polysaccharide with whey protein, lentil protein, and soy protein isolates

The electrostatic interactions and complex formation of Tremella fuciformis polysaccharide (TPS) with whey protein (WPI), lentil protein (LPI), and soy protein (SPI) isolates were studied. The molecular size and components in each protein isolate complexed with TPS were characterized, along with the structural changes in the protein components, induced by TPS complexation. The stability of emulsions prepared with protein:TPS complexes was also evaluated (pH 4.5). Compared to WPI, the LPI and SPI protein components exhibited more negative charges and larger molecular sizes. Independent of the isolate type, pHc of all protein:TPS systems remained unchanged and pHɸ1 shifted to higher pHs as the protein/TPS ratio increased; the pHopt of WPI:TPS and SPI:TPS occurred at higher values as the protein/TPS ratio increased, while the pHopt of LPI:TPS system was less dependent on the biopolymer mixing ratio, probably due to the lower solubility of LPI. Protein components such as β-LG in WPI, convicilin, vicilin, and basic legumin in LPI, and α’ subunits of 7S β-conglycinin and acidic subunits of 11S glycinin in SPI might be the main components interacting with TPS for complex formation. Different proteins exhibited distinct trends in changing their secondary structural elements when interacting with TPS. At pH 4.5, a high proportion of TPS increased the stability of protein emulsion, regardless of the protein used. The WPI:TPS emulsions with low content of TPS were highly destabilized due to the formation of insoluble WPI:TPS complex coacervates, a phenomenon not observed in emulsions stabilized by the LPI:TPS or SPI:TPS systems.

Co-encapsulation of borage seed oil and peppermint oil blends within ultrasound-assisted soy protein isolate/purity gum ultra complex nanoparticles: Fabrication, structural interaction mechanisms, and in vitro digestion studies

This study aimed at co-encapsulating borage seed oil (BSO)- and peppermint oil (PO) blends in ultrasound-assisted complex nanoparticles stabilized by soy protein isolate (SPI) and purity gum ultra (PGU) in different ratios: SPI/PGU-1:0 (NP1), 0:1 (NP2), 1:1 (NP3), 1:3 (NP4), and 3:1 (NP5). The BSO- and PO-loaded SPI/PGU complex nanoparticles (BP-loaded SPNPs) coded as NP4 (SPI-PGU-1:3) revealed a zeta potential of −33.27 mV, a PDI of 0.14, and the highest encapsulation efficiency (81.38 %). The main interactions observed among SPI, PGU, BSO, PO, and a blend of BSO and PO, as determined by FTIR and molecular docking, involved hydrophobic effects, electrostatic attraction, and H-bonding. These interactions played crucial roles in the production of BP-loaded SPNPs. XRD results validated the alterations in the structure of BP-loaded SPNPs caused by varying proportions of SPI and PGU. The thermal capacity of BP-loaded SPNPs (NP4), as determined by TGA, exhibited the lowest amount of weight loss compared to other BP-loaded SPNPs. Morphological results revealed that NP4 and NP5 exhibited a spherical surface and two distinguishable layers, indicating successful coating of PGU onto the droplet surface. In addition, BP-loaded SPNPs (NP4) exhibited a higher antioxidant effect due to their improved progressive release and prolonged release of co-encapsulated BSO and PO during in vitro digestion. The comprehensive investigation of the co-encapsulation of BSO and PO in complex nanoparticles, dietary supplements, and double-layered emulsified systems provides valuable insights into the development of functional foods.

Characterization of the extracellular proteases from Bacillus inaquosorum strain E1-8 and its application in the preparation of hydrolysates from plant and animal proteins with antioxidant, antifreeze and anti-browning properties.

Bacillus inaquosorum strains is widely recognized for their plant-growth-promoting and biocontrol capabilities, yet their roles in protease production remain unclear. The present study aimed to comprehensively assess the protease-producing performance of B. inaquosorum strain E1-8, at the same time as exploring the novel application of agricultural Bacillus proteases in the preparation of protein hydrolysates for fresh-cut fruits preservation. First, genomic sequencing revealed the diversity of E1-8 proteases, indicating 15 putative extracellular proteases. Subsequently, the fermentation conditions for E1-8 protease production were optimized, with sweet potato powder and soybean meal identified as the most suitable carbon and nitrogen sources, respectively, resulting in a maximum protease activity of 321.48 U mL-1. Upon culturing the strain under these optimized conditions, only an S8 family serine protease and an M48 family metalloprotease were revealed by secretomic analysis and protease inhibitor assays. Additionally, the optimal protease conditions for generating protein hydrolysates from soy, pea, fish and porcine proteins were determined. The molecular weight of the hydrolysates primarily ranged from 2000 to 180 Da, with a total of 17 amino acids identified. The application of these hydrolysates demonstrated a 2,2-diphenyl-1-picrylhydrazyl (i.e. DPPH) scavenging activity ranging from 58.64% to 84.12%, significantly reducing of the melting peaks and the freezing points. Furthermore, the browning index of apple slices stored at 4 °C decreased by 14.81% to 22.15% on the second day, and similar effects were observed in fresh-cut banana stored at 4 °C for 7 days. The protein hydrolysates obtained exhibit remarkable antioxidant, antifreeze and anti-browning properties for fresh-cut fruits. © 2024 Society of Chemical Industry.