In vitro digestion mimicking conditions in adults and elderly reveals digestive characteristics of pork from different cooking ways.

This study aimed to investigate the impact of three cooking ways (sous vide (SV), frying (FR) and roasting (RO)) on pork protein digestion characteristics under conditions simulating healthy adult (control, C) and elderly individuals with achlorhydria (EA). Changes in degree of hydrolysis (DH), SDS-PAGE profiles, zeta potential, particle size and secondary structure during digestion were evaluated. Our results revealed the EA condition markedly affected the protein digestion process of pork with different cooking ways. The DH values of SV (25.62%), FR (21.38%) and RO (19.40%) under the EA condition were significantly lower than those of under the control condition (38.32%, 33.00% and 30.86%, respectively). Moreover, differences were also observed among three cooking ways under the EA condition. For a given cooking way, the differences between control and EA conditions gradually diminished from the gastric to the intestinal phase. Under a certain digestion condition, SV maintained the highest degree of digestion throughout the process, particularly under the EA condition. Therefore, we conclude that pork cooked by sous vide is more recommendable for the elderly considering protein digestibility.

Comparison of nutritional profile between plant-based meat analogues and real meat: A review focusing on ingredients, nutrient contents, bioavailability, and health impacts.

In order to fully understand the nutritional heterogeneity of plant-based meat analogues and real meat, this review summarized their similarities and differences in terms of ingredients, nutrient contents, bioavailability and health impacts. Plant-based meat analogues have some similarities to real meat. However, plant-based meat analogues are lower in protein, cholesterol and VB12 but higher in dietary fiber, carbohydrates, sugar, salt and various food additives than real meat. Moreover, some nutrients in plant-based meat analogues, such as protein and iron, are less bioavailable. There is insufficient evidence that plant-based meat analogues are healthier, which may be related to the specific attributes of these products such as formulation and degree of processing. As things stand, it is necessary to provide comprehensive nutrition information on plant-based meat products so that consumers can make informed choices based on their nutritional needs.

Anoikis and SPP1 in idiopathic pulmonary fibrosis: integrating bioinformatics, cell, and animal studies to explore prognostic biomarkers and PI3K/AKT signaling regulation.

OBJECTIVE: This study aims to explore the relevance of anoikis in idiopathic pulmonary fibrosis (IPF) and identify associated biomarkers and signaling pathways. METHOD: Unsupervised consensus cluster analysis was employed to categorize IPF patients into subtypes. We utilized Weighted Gene Co-Expression Network Analysis (WGCNA) and Protein-Protein Interaction network construction to identify anoikis-related modules and key genes. A prognostic signature was developed using Lasso and multivariate Cox regression analysis. Single-cell sequencing assessed hub gene expression in various cell types, and both cell and animal experiments confirmed IPF-related pathways. RESULTS: We identified two distinct anoikis-associated subtypes with differing prognoses. WGCNA revealed essential hub genes, with SPP1 being prominent in the anoikis-related signature. The anoikis-related signature is effective in determining the prognosis of patients with IPF. Single-cell sequencing highlighted significant differences in SPP1 expression, notably elevated in fibroblasts derived from IPF patients. In vivo and in vitro experiments demonstrated that SPP1 enhances fibrosis in mouse lung fibroblasts by regulating p27 through the PI3K/Akt pathway. CONCLUSION: Our research demonstrates a robust prognostic signature associated with anoikis and highlights SPP1 as a pivotal regulator of the PI3K/AKT signaling pathway in pulmonary fibrosis.

Visceral adipose tissue and risk of diabetic nephropathy: A Mendelian randomization study.

OBJECTIVE: Previous observational studies have established a correlation between visceral adipose tissue (VAT) and diabetic nephropathy (DN). However, the causality of this association remains unclear. Therefore, the aim of this study was to investigate the causal association between VAT and DN by employing two-sample Mendelian randomization (MR) methods. METHODS: The primary MR approach employed was the random-effects inverse-variance weighted (IVW) method. Additionally, we employed alternative methods, including the weighted median (WM) approach, MR-Egger regression, and Mendelian randomization pleiotropy residual sum and outlier (MR-PRESSO). Sensitivity analyses were conducted to evaluate the robustness of the MR analyses. RESULTS: Genetically predicted higher VAT mass was causally associated with a higher risk of DN. The results of the MR analyses were as follows: IVW(Beta = 0.948, odds ratio (OR) = 2.581, 95 % confidence interval (CI) = 2.100-3.173, p = 1.980e-19), WM (Beta = 1.126, OR = 3.082, 95 % CI = 2.278-4.171, p = 2.997e-13), MR-Egger (Beta = 1.315, OR = 3.724, 95 % CI = 1.981-6.998, p = 6.446e-05), and MR-PRESSO (Beta = 0.914, OR = 2.493, 95 % CI = 2.292-2.695, p = 3.121e-16). No pleiotropy was detected (p = 0.230). CONCLUSIONS: This study provided genetic evidence that higher VAT mass was causally associated with a higher risk of DN.

A review: analysis of technical challenges in cultured meat production and its commercialization.

The cultured meat technology has developed rapidly in recent years, but there are still many technical challenges that hinder the large-scale production and commercialization of cultured meat. Firstly, it is necessary to lay the foundation for cultured meat production by obtaining seed cells and maintaining stable cell functions. Next, technologies such as bioreactors are used to expand the scale of cell culture, and three-dimensional culture technologies such as scaffold culture or 3D printing are used to construct the three-dimensional structure of cultured meat. At the same time, it can reduce production costs by developing serum-free medium suitable for cultured meat. Finally, the edible quality of cultured meat is improved by evaluating food safety and sensory flavor, and combining ethical and consumer acceptability issues. Therefore, this review fully demonstrates the current development status and existing technical challenges of the cultured meat production technology with regard to the key points described above, in order to provide research ideas for the industrial production of cultured meat.

A General and Convenient Peptide Self-Assembling Mechanism for Developing Supramolecular Versatile Nanomaterials Based on The Biosynthetic Hybrid Amyloid-Resilin Protein.

Self-assembling peptides are valuable building blocks to fabricate supramolecular biomaterials, which have broad applications from biomedicine to biotechnology. However, limited choices to induce different globular proteins into hydrogels hinder these designs. Here, an easy-to-implement and tunable self-assembling strategy, which employs Ure2 amyloidogenic peptide, are described to induce any target proteins to assemble into supramolecular hydrogels alone or in combination with notable compositional control. Furthermore, the collective effect of nanoscale interactions among amyloid nanofibrils and partially disordered elastomeric polypeptides are investigated. This led to many useful macroscopic material properties simultaneously emerging from one pure protein material, i.e. strong adhesion to any substrates under wet conditions, rapidly self--assembling into robust and porous hydrogels, adaptation to remodeling processes, strongly promoting cell adhesion, proliferation and differentiation. Moreover, he demonstrated this supramolecular material's robust performance in vitro and vivo for tissue engineering, cosmetic and hemostasis applications and exhibited superior performance compared to corresponding commercial counterparts. To the best of his knowledge, few pure protein-based materials could meet such seemingly mutually exclusive properties simultaneously. Such versatility renders this novel supramolecular nanomaterial as next-generation functional protein-based materials, and he demonstrated the sequence level modulation of structural order and disorder as an untapped principle to design new proteins.

Morphology-Based Prediction of Proliferation and Differentiation Potencies of Porcine Muscle Stem Cells for Cultured Meat Production.

Inconsistent efficiency of cell production caused by cellular quality variations has become a significant problem in the cultured meat industry. In our study, morphological information on passages 5-9 of porcine muscle stem cells (pMuSCs) from three lots was analyzed and used as input data in prediction models. Cell proliferation and differentiation potencies were measured by cell growth rate and average stained area of the myosin heavy chain. Analysis of PCA and heatmap showed that the morphological parameters could be used to discriminate the differences of passages and lots. Various morphological parameters were analyzed, which revealed that accumulating time-course information regarding morphological heterogeneity in cell populations is crucial to predicting the potencies. Based on the 36 and 60 h morphological profiles, the best proliferation potency prediction model (R2 = 0.95, RMSE = 1.1) and differentiation potency prediction model (R2 = 0.74, RMSE = 1.2) were explored. Correlation analysis demonstrated that morphological parameters selected in models are related to the quality of porcine muscle stem cells.

Plant-based meat analogues enhance the gastrointestinal motility function and appetite of mice by specific volatile compounds and peptides.

Eating behavior is critical for maintaining energy homeostasis. Previous studies have found that plant-based meat analogues increased diet intake in mice compared with animal meat under a free feeding mode, however the reasons were unclear. To explore the underlying mechanisms of plant-based meat analogues increasing diet intake, mice were fed animal or plant-based pork and beef analogue diets, respectively. Biochemical and histological analyses were performed to evaluate appetite-regulating hormones and gastrointestinal motility function. Peptiomics and GC-IMS were applied to identify key substances. We found that the intake of plant-based meat analogues significantly enhanced the gastrointestinal motility function of mice. The long-term intake (68 days) of plant-based meat analogues significantly increased the muscle layer thickness of the duodenum and jejunum of mice; the activity of gastrointestinal cells of Cajal were also promoted by upregulating the expression of c-kit related signals as compared to animal meat; plant-based meat analogues intake markedly enhanced the signal intensity of the intestinal neurotransmitter 5-hydroxytryptamine (5-HT) by upregulating the expression of 5-HT synthase and receptors but downregulating its transporter and catabolic enzyme in the intestine. Moreover, plant-based meat analogues intake significantly increased levels of appetite-stimulating factors in the peripheral or hypothalamus but reduced levels of appetite-suppressing factors compared with animal meat. Specific volatile compounds were significantly associated with appetite regulating factors. Among them, 7 substances such as linalool have a potential promoting effect on food intake. Besides, different digestive peptides in gastrointestinal tract may affect eating behavior mainly through the neuroactive ligand-receptor interaction pathway, exerting hormone-like effects or influencing endocrine cell secretion. These findings preliminarily clarified the mechanism of plant-based meat analogues promoting diet intake and provided a theoretical basis for a reasonable diet.

Tea polyphenols coated sodium alginate-gelatin 3D edible scaffold for cultured meat.

This study aimed to use edible scaffolds as a platform for animal stem cell expansion, thus constructing block-shaped cell culture meat. The tea polyphenols (TP)-coated 3D scaffolds were constructed of sodium alginate (SA) and gelatin (Gel) with good biocompatibility and mechanical support. Initially, the physicochemical properties and mechanical properties of SA-Gel-TP scaffolds were measured, and the biocompatibility of the scaffolds was evaluated by C2C12 cells. SEM results showed that the scaffold had a porous laminar structure with TP particles attached to the surface, while FT-IR results also demonstrated the encapsulation of TP coating on the scaffold. In addition, the porosity of all scaffolds was higher than 40% and the degradation rate during the incubation cycle was less than 40% and the S2-G1-TP0.1-3 h scaffold has excellent cell adhesion and extension. Subsequently, we inoculated rabbit skeletal muscle myoblasts (RbSkMC) on the scaffold and induced differentiation. The results showed good adhesion and extension behavior of RbSkMC on S2-G1-TP0.1-3 h scaffolds with high expression of myogenic differentiation proteins and genes, and SEM results confirmed the formation of myotubes. Additionally, the adhesion rate of cells on scaffolds with TP coating was 1.5 times higher than that on scaffolds without coating, which significantly improved the cell proliferation rate and the morphology of cells with extension on the scaffolds. Furthermore, rabbit-derived cultured meat had similar appearance and textural characteristics to fresh meat. These conclusions indicate the high potential of the scaffolds with TP coating as a platform for the production of cultured meat products.

Maturity-onset diabetes of the young type 9 or latent autoimmune diabetes in adults: A case report and review of literature.

BACKGROUND: Maturity-onset diabetes of the young (MODY) is a monogenic genetic disease often clinically misdiagnosed as type 1 or type 2 diabetes. MODY type 9 (MODY9) is a rare subtype caused by mutations in the PAX4 gene. Currently, there are limited reports on PAX4-MODY, and its clinical characteristics and treatments are still unclear. In this report, we described a Chinese patient with high autoimmune antibodies, hyperglycemia and a site mutation in the PAX4 gene. CASE SUMMARY: A 42-year-old obese woman suffered diabetes ketoacidosis after consuming substantial amounts of beverages. She had never had diabetes before, and no one in her family had it. However, her autoantibody tested positive, and she managed her blood glucose within the normal range for 6 mo through lifestyle inter-ventions. Later, her blood glucose gradually increased. Next-generation sequencing and Sanger sequencing were performed on her family. The results revealed that she and her mother had a heterozygous mutation in the PAX4 gene (c.314G>A, p.R105H), but her daughter did not. The patient is currently taking liraglutide (1.8 mg/d), and her blood glucose levels are under control. Previous cases were retrieved from PubMed to investigate the relationship between PAX4 gene mutations and diabetes. CONCLUSION: We reported the first case of a PAX4 gene heterozygous mutation site (c.314G>A, p.R105H), which does not appear pathogenic to MODY9 but may facilitate the progression of latent autoimmune diabetes in adults.

Visceral adipose tissue and risk of nonalcoholic fatty liver disease: A Mendelian randomization study.

OBJECTIVE: Observational studies have shown that visceral adipose tissue (VAT) can increase the risk of nonalcoholic fatty liver disease (NAFLD). However, the causality of this association remains unclear. Therefore, this study aimed to explore the causal association between VAT and NAFLD. DESIGN: We obtained single-nucleotide polymorphisms strongly associated with VAT (n = 325,153) from large-scale genome-wide association studies. Summary-level data for NAFLD (2275 cases and 375,002 controls) was available from the FinnGen consortium. We applied two-sample Mendelian randomization (MR) to determine the causal association between VAT and NAFLD. The random-effects inverse-variance weighted (IVW) method was used as the main MR approach, with alternate methods including the weighted median (WM) approach and MR-Egger regression. In addition, we conducted sensitivity analyses to assess the robustness of MR analyses. RESULTS: Genetically predicted higher VAT mass is causally associated with a higher risk of NAFLD. The three analysis results of MR were as follows: IVW (ß = 0.665, odds ratio [OR] = 1.944, 95% confidence interval [CI] = 1.482-2.550, p = 1.58e-06], WM (ß = 0.615, OR = 1.849, 95% CI = 1.272-2.689, p = 1.29e-03), and MR-Egger (ß = 1.250, OR = 3.490, 95% CI = 1.522-7.998, p = 3.52e-03). In the sensitivity analysis, the data showed heterogeneity (p < 0.05) but no pleiotropy (p = 0.145). CONCLUSION: This study provided genetic evidence that higher VAT mass causally associated with a higher risk of NAFLD. The amount of VAT could be reduced using a therapeutic strategy for managing NAFLD.

Unexpected variations in the effects of ultrasound-assisted myofibrillar protein processing under varying viscosity conditions.

The efficient synthesis of myofibrillar protein(MRN)-gallic acid (GAD) complex in ultrasound (UID)-assisted processing is a challenging problem in food manufacturing. In this investigation, the effect of viscosity characteristics on the efficiency of UID processing in MRN-based beverages was analyzed. Both viscosity and surface tension can increase sono-physico-chemical effects on the degradation of terephthalic acid and crystal violet, with surface tension having a more significant effect (negative correlation, R2 = 0.99) than viscosity (positive correlation, R2 = 0.79). The structural indicators and microstructure demonstrated that the reaggregation and refolding of the MRN structure during the modification procedure occurred with relatively small three-dimensional dimensions. Compared to the MRN/GAD4 group, the water contact angle of the MRN/GAD7 system enhanced by 129.44%, leading to greater system stability. The ABTS-scavenging capacity of the system increased by approximately 19.45% due to the increase in viscosity of these two categories.

The Effect of Long-Term Passage on Porcine SMCs' Function and the Improvement of TGF-ß1 on Porcine SMCs' Secretory Function in Late Passage.

Cultured meat is one of the meat substitutes produced through tissue engineering and other technologies. Large-scale cell culture is the key for cultured meat products to enter the market. Therefore, this study is aimed to explore the effect of long-term passage in vitro on smooth muscle cells (SMCs) and the effect of transforming growth factor-ß1 (TGF-ß1) on SMCs in the late passage. Multiple passages lead to the decline of the proliferation rate of SMCs in the proliferation stage and the differentiation ability in the differentiation stage. Transcriptome results showed that the ECM pathway and aging-related signaling pathways were significantly up-regulated in the late passage period. TGF-ß1 did not promote SMCs of late passage proliferation at the proliferation stage but promoted the gene and protein expression of collagen as the main protein of the extracellular matrix proteins at the differentiation stage. In addition, proteomic analysis revealed that TGF-ß1 promoted the expression of cell adhesion molecules which activate the Hippo signaling pathway and the HIF-1 signaling pathway and further promoted the production of collagen-containing extracellular matrix proteins. This could provide ideas for large-scale production of cultured meat products using SMCs.

Different protein-anthocyanin complexes engineered by ultrasound and alkali treatment: Structural characterization and color stability.

Through alkali treatment (AT) and ultrasound (UT)-assisted processing producing covalent protein-anthocyanin complexes, we investigated the impact of treatment methods and protein types on conjugation efficiency, protein structure, and color stability. Our findings revealed the effective grafting of anthocyanins (ACNs) onto proteins, with myofibrillar protein (MP) exhibiting the highest conjugation efficiency of 88.33% after UT (p <.05). UT accelerated the structure unfolding of distinct protein samples, leading to the exposure of sulfhydryl, and hydrophobic groups in proteins, and enhanced the oxidation stability of ACNs. Notably, the modified ACNs maintained a favorable pH-color relationship, while U-MP showed a significantly higher absorbance (0.4998) than the other groups (p <.05) at pH 9.0, demonstrating an outstanding color improvement. UT-assisted processing also accelerated the NH3 reaction. Thus, the combination of UT and MP holds the potential for pH-color-responsive intelligent packaging and increases the efficiency of UT processing.

Evaluation of Temperature Uniformity in a Middle-Refrigerated Truck Loaded with Pig Carcasses.

In this study, we constructed a calculation model to determine the internal temperature field distribution in a medium-sized refrigeration truck with the dimensions of 4.1 m × 2.2 m × 2.2 m. Wind speed, air temperature, and carcass temperature were designated as the initial conditions. The k-ε model of computational fluid dynamics was used to simulate different wind speeds and ventilation duct settings on the carriage. Additionally, under specific boundary conditions, the speed of the air outlet, the types of ventilation ducts, and the carcass loads were all varied to determine the uniformity of the temperature field. The results showed that, when the air outlet speed was 5 m/s, the temperature field in the refrigerated truck was relatively more uniform. The simulated results were in good agreement with the measured results. The average absolute error was 0.35 °C, and the average relative error was 9.23%.

Gellan gum-gelatin scaffolds with Ca2+ crosslinking for constructing a structured cell cultured meat model.

As an emerging technology to obtain protein by culturing animal-derived cells in vitro, it is crucial to construct 3D edible scaffolds to prepare structured cell cultured meat products. In this study, a scaffold based on gellan gum (GG)-gelatin (Gel) was prepared and further cross-linked with Ca2+. FTIR confirmed the electrostatic interaction between GG and Gel and the ionic cross-linking of Ca2+ and carboxyl groups, and SEM images showed the porous structure of the scaffolds. The staining results showed that scaffolds with high concentrations of Ca2+ had higher biocompatibility than scaffolds with low concentrations of Ca2+ and non-crosslinked scaffolds, and scaffolds Ca2+-GG2-Gel3-0.5 adhered to more cells and were more conducive to cell spreading. The immunofluorescence staining, SEM images, Western blot, and RT-qPCR showed that the scaffolds supported the proliferation and myogenic differentiation of chicken skeletal muscle satellite cells (CSMSCs) and myotubes were formed on the scaffolds. Finally, the scaffolds were stained and fried after culturing. The results of the textural and chromatic analysis showed that the texture and color of the scaffolds were similar to fresh meat and meat products. These results showed that ionically crosslinked GG-Gel scaffolds are biocompatible and stable for structured cell cultured meat models.

SaaS sRNA promotes Salmonella intestinal invasion via modulating MAPK inflammatory pathway.

Salmonella Enteritidis is a foodborne enteric pathogen that infects humans and animals, utilizing complex survival strategies. Bacterial small RNA (sRNA) plays an important role in these strategies. However, the virulence regulatory network of S. Enteritidis remains largely incomplete and knowledge of gut virulence mechanisms of sRNAs is limited. Here, we characterized the function of a previously identified Salmonella adhesive-associated sRNA (SaaS) in the intestinal pathogenesis of S. Enteritidis. We found that SaaS promoted bacterial colonization in both cecum and colon of a BALB/c mouse model; it was preferentially expressed in colon. Moreover, our results showed that SaaS enhanced damage to mucosal barrier by affecting expressions of antimicrobial products, decreasing the number of goblet cells, suppressing mucin gene expression, and eventually reducing thickness of mucus layer; it further breached below physical barrier by strengthening invasion into epithelial cells in Caco-2 cell model as well as decreasing tight junction expressions. High throughput 16S rRNA gene sequencing revealed that SaaS also altered gut homeostasis by depleting beneficial gut microbiota while increasing harmful ones. Furthermore, by employing ELISA and western blot analysis, we demonstrated that SaaS regulated intestinal inflammation through sequential activation P38-JNK-ERK MAPK signaling pathway, which enabled immune escape at primary infection stage but strengthened pathogenesis at later stage, respectively. These findings suggest that SaaS plays an essential role in the virulence of S. Enteritidis and reveals its biological role in intestinal pathogenesis.

A comparison of the impacts of different polysaccharides on the sono-physico-chemical consequences of ultrasonic-assisted modifications.

This study aimed to examine the sono-physico-chemical effects of ultrasound (UND) and its impact on the conjugate rates of morin (MOI) following the addition of polysaccharides in various conditions. In comparison to the control group, the incorporation of quaternary ammonium chitosan decreased the rate of MOI conjugation by 17.38%, but the addition of locust bean gum enhanced the grafting rate by 29.89%. Notably, the highest degree of myofibrillar protein (MRN) unfolding (fluorescence intensity: 114435.50), the most stable state (-44.98 mV), and the greatest specific surface area (393.06 cm2/cm3) were observed in the UMP/LBG group. The outcomes of atomic force microscopy and scanning electron microscopy revealed that the inclusion of locust bean gum led to a different microscopic morphology than the other two polysaccharides, which may be the primary cause of the strongest sono-physico-chemical effects of the system. This work demonstrated that acoustic settings can be tuned based on the characteristics of polysaccharides to maximize the advantages of sono-physico-chemical impacts in UND-assisted MOI processing.

Suppression mechanism of L-lysine on the Epigallocatechin-3-gallate-induced loss of myofibrillar protein gelling potential.

As a natural antioxidant, Epigallocatechin-3-gallate (EGCG) needed to be added in high doses to maintain the quality of meat products. However, high doses of EGCG caused the excessive aggregation of myofibrillar protein (MP), which damaged the gel properties of MP gels. Therefore, the purpose of this study was to investigate the mitigation of EGCG-induced loss of MP gelling potential by L-Lysine (L-Lys). The results showed that the addition of 20 mM L-Lys induced excessive unfolding and loose aggregation of MP at 10 µmol/g EGCG, and hence, reducing the solubility (14.5%) and the tryptophan fluorescence, and forming a network structure with a large aperture. Therefore, the cooking loss was decreased from 29.20% to 15.13%, and the strength of MP gels was decreased from 0.35 N to 0.17 N. However, L-Lys hindered the hydrogen bonding interactions and hydrophobic interactions between MP and EGCG by competing the binding sites of MP at 50 µmol/g EGCG, which was supported by the Zeta potential, surface hydrophobicity, FTIR and molecular docking analysis. Thus L-Lys mitigated the protein aggregation caused by 50 µmol/g EGCG, improved the solubility (23.02%∼86.99%) and apparent viscosity, which were beneficial for the formation of a continuous network structure in MP gels. Therefore, the cooking loss of MP gels was decreased from 52.40% to 41.30%, and the gel strength was enhanced from 0.13 N to o.22 N with 20 mM L-Lys addition. The present study could provide a new strategy for increasing the amounts of EGCG in meat products without damaging the gel properties of meat products.

Quality Control of Jinhua Ham from the Influence between Proteases Activities and Processing Parameters: A Review.

Endogenous proteases are significant for Jinhua ham quality. Protein degradation affects the chemical traits, texture and the formation of flavor substances. Protease activities are affected by different process parameters, such as processing temperature, maturation time, salt content and the drying rate. They affect ham quality, which can be controlled by process parameters. The influences of key factors on Jinhua ham quality are briefly summarized, which can provide a theoretical basis for the selection of specific parameters in dry-cured ham processing. Furthermore, some suggestions are proposed for correcting and improving the flavor and textural defects of ham, yet the effectiveness depends on the operating conditions. The determination of enzyme activity is not real-time and unsupervised at the moment. Future research will focus on the determination of the actual endogenous protease activity and the quantitative relationship between the enzyme activity and main processing parameters.