Micro- and Macroalgae in Meat Products.

Technology in the meat industry is advancing to create healthier and more sustainable food. Incorporating micro- and macroalgae into meat products presents an exciting possibility for the meat sector to develop functional food, given that they serve as excellent natural sources of nutrients and bioactive compounds. This review aims to systematically outline the impact of incorporating whole algae and their extracts into various meat products, examining their effects on quality, physicochemical and functional properties, sensory characteristics, and potential for enhancing shelf life. Adding algae to meat products generally increased pH values, with variations influenced by concentration, type, initial pH, and storage time. The protein content was mainly unaffected, except for Nori and Chlorella. Algae contributed to lower moisture and higher ash content due to dietary fiber. While including algae improved water-holding capacity and decreased cooking loss, it often led to increased hardness and chewiness. Algae and their extracts influenced color attributes, with variations based on the algae type. Sensory properties were distinctively affected, generally reducing overall acceptability, although Sea tangle at concentrations of 1-3% showed acceptable scores. Chlorella and Sea tangle positively impacted microbiology during refrigerated storage, while algae and their extracts demonstrated strong antioxidant activity.

Investigation of the peptides with calcium chelating capacity in hydrolysate derived from spent hen meat.

Calcium peptide chelates are developed as efficient supplements for preventing calcium deficiency. Spent hen meat (SHM) contains a high percentage of proteins but is generally wasted due to the disadvantages such as hard texture. We chose the underutilized SHM to produce peptides to bind calcium by proteolysis and aimed to investigate chelation between calcium and peptides in hydrolysate for a sustainable purpose. The optimized proteolysis conditions calculated from the result of response surface methodology for two-step hydrolysis were 0.30% (wenzyme/wmeat) for papain with a hydrolysis time of 3.5 h and 0.18% (wenzyme/wmeat) for flavourzyme with a hydrolysis time of 2.8 h. The enzymatic hydrolysate (EH) showed a binding capacity of 63.8 ± 1.8 mg calcium/g protein. Ethanol separation for EH improved the capacity up to a higher value of 68.6 ± 0.6 mg calcium/g protein with a high association constant of 420 M-1 (25°C) indicating high stability. The separated fraction with a higher amount of Glu, Asp, Lys, and Arg had higher calcium-binding capacity, which was related to the number of ─COOH and ─NH2 groups in peptide side chains according to the result from amino acid analysis and Fourier transform infrared spectroscopy. Two-step enzymatic hydrolysis and ethanol separation were an efficient combination to produce peptide mixtures derived from SHM with high calcium-binding capacity. The high percentage of hydrophilic amino acids in the separated fraction was concluded to increase calcium-binding capacity. This work provides foundations for increasing spent hen utilization and developing calcium peptide chelates based on underutilized meat.

Effects of Fermentation with Tetragenococcus halophilus and Zygosaccharomyces rouxii on the Volatile Profiles of Soybean Protein Hydrolysates.

The effects of fermentation with lactic acid bacteria (LAB) and yeast on the aroma of samples were analyzed in this work. The volatile features of different soybean hydrolysates were investigated using both GC-MS and GC-IMS. Only 47 volatile flavor compounds (VFCs) were detected when using GC-IMS, while a combination of GC-MS and GC-IMS resulted in the identification of 150 compounds. LAB-yeast fermentation could significantly increase the diversity and concentrations of VFCs (p < 0.05), including alcohols, acids, esters, and sulfurs, while reduce the contents of aldehydes and ketones. Hierarchical clustering and orthogonal partial least squares analyses confirmed the impact of fermentation on the VFCs of the hydrolysates. Seven compounds were identified as significant compounds distinguishing the aromas of different groups. The partial least squares regression analysis of the 25 key VFCs (ROAV > 1) and sensory results revealed that the treatment groups positively correlated with aromatic, caramel, sour, overall aroma, and most of the key VFCs. In summary, fermentation effectively reduced the fatty and bean-like flavors of soybean hydrolysates, enhancing the overall flavor quality, with sequential inoculation proving to be more effective than simultaneous inoculation. These findings provided a theoretical basis for improving and assessing the flavor of soybean protein hydrolysates.

The influence of protein oxidation on structure, pepsin diffusion, and in vitro gastric digestion of SPI emulsion.

The stability behaviors of oxidized SPI emulsions under in vitro gastric conditions and the effects of pepsin diffusion on the proteolysis of emulsions were investigated using a static gastric model and the fluorescence recovery after photobleaching method. Results showed that protein oxidation increased the particle size of droplets and decreased the viscoelasticity of the interfacial layer. Compared to the control group (82.81 m2/s), the pepsin diffusivity decreased to 68.52 m2/s (7LA + LOX group) due to the space hindrance of oil droplets. After gastric digestion, protein hydrolysates were re-absorbed on the oil-water interface and formed a thick layer, thereby decreasing the size of oil droplets and reducing the contents of free amino acids in gastric digesta. The protein oxidation may affect the adsorption of interfacial proteins and alter the distribution of droplets, decreasing pepsin diffusion and ultimately impairing the emulsion gastric digestion. And this should be considered in the design of emulsion as the controllable delivery system.

Eurasian consumers' food safety beliefs and trust issues in the age of COVID-19: evidence from an online survey in 15 countries.

BACKGROUND: This investigation provides an important insight into Eurasian consumers' food safety beliefs and trust issues influenced by the COVID-19 pandemic. An online survey was conducted in 15 European and Asian countries involving more than 4000 consumers. RESULTS: It has confirmed that different socioeconomic characteristics, cultural aspects and education levels shape food safety perceptions within Eurasian countries. The COVID-19 pandemic influenced their beliefs and trust in food safety, which is relatively low on average. However, it is significantly higher for European consumers (especially European Union ones) compared to their Asian counterparts. Both Asian and European respondents agreed that food fraud and climate changes represent a food safety issue. However, European consumers were less concerned regarding the food safety of genetically modified foods and meat and dairy analogs/hybrids. Asian consumers were, to a greater extent, worried about the risk of getting COVID-19 from food, restaurants, food retail establishments and home food deliveries. CONCLUSION: Eurasian consumers have put their greatest extent of trust, when food safety assurance is concerned, into food scientists and food producers holding a food safety certificate. Broadly, they are uncertain to what extent their federal governments and food inspectors are competent, able and efficient in ensuring food safety. Higher education of Eurasian consumers was followed by increased food safety confidence in all parts of the food chain. © 2023 The Authors. Journal of The Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

Prospects and challenges for the application of salty and saltiness-enhancing peptides in low-sodium meat products.

A long-term high-sodium diet has been reported to increase the incidence of cardiovascular diseases and other diseases, including osteoporosis, gastric cancer, stomach cancer, and kidney stones. Meat products contain high NaCl content and contribute to approximately 20% of the total sodium intake, so reducing its sodium content has always been the critical focus of industries and researchers. Salty and saltiness-enhancing peptides (SSEP) are a potential salt substitute that exhibits a salt taste or saltiness-enhancing activity. The partial replacement of NaCl by SSEP in low-sodium meat products has been a technological challenge. This review discussed the salt taste transduction mechanism of SSEP. The current studies about preparing SSEP based on different protein sources were summarized. Further, the effects of SSEP combined with other chloride salts, such as KCl and CaCl2, on the sensory properties of meat products were summarized. Finally, the challenges associated with applying the peptide to low-sodium meat products were discussed, focusing on the efficient preparation method and the effect of meat product processing methods and matrices on the efficacy of SSEP.

Huangshui Polysaccharide Exerts Intestinal Barrier Protective Effects through the TLR4/MyD88/NF-κB and MAPK Signaling Pathways in Caco-2 Cells.

Several reports have demonstrated that natural polysaccharides exert protective effects on intestinal barrier function. In our previous study, we isolated a polysaccharide named HSP-W from Huangshui (HS). In the present study, the protective role of HSP-W in LPS-induced intestinal barrier dysfunction was determined by several molecular biological techniques. The results showed that HSP-W treatment alleviated the deduced TEER and increased the permeability of intestinal epithelial cells induced by LPS through inhibiting the release of inflammatory cytokines and enhancing the expression of tight junction (TJ) proteins. The underlying molecular mechanisms were elucidated by RNA-seq technique, which indicated that the differentially expressed genes (DEGs) between the LPS-treated and LPS+HSP-W-treated groups were enriched in the "MAPK" signaling pathway. Notably, the overlapping DEGs reversed by HSP-W intervention highlighted the pathways of the "Toll-like receptor" and "NF-κB" signaling pathways. The suppression of p38 and NF-κB were mediated by the inhibition of MyD88. Furthermore, HSP-W treatment prevented the translocation of NF-κB to nucleus, thus inhibiting the release of TNF-α, IL-6, and IL-1ß. Overall, HSP-W has beneficial effects on LPS-induced inflammation; it protects the intestinal barrier from injury in Caco-2 cells through inhibiting the TLR4/MyD88/NF-κB and p38 MAPK signaling pathways.

Heteroprotein complex between soy protein isolate and lysozyme: Protein conformation, lysozyme activity, and structural characterization.

Heteroprotein complexes are formed by electrostatic interactions of oppositely charged proteins in a purely aqueous environment. Understanding the relationship between their structural and functional properties will contribute to their tailor-made applications. Therefore, this study investigated the protein conformation, assembling structure, and enzyme activity of soy protein isolate/lysozyme (SPI/LYS) complexes at mass ratios of 2:1 (soluble complex) and 1:1.3 (stoichiometric ratio). Electrostatic complexation increased the surface hydrophobicity of complexes. Their surface hydrophobicity decreased with increasing NaCl concentrations and reached the theoretical values at the critical salt concentration of 200 mM NaCl. Electrostatic complexation did not decrease the LYS activity (∼43,000 units/mg). SPI/LYS complexes exhibited flocculated structures in which the two proteins were unevenly distributed; these were typical amorphous complexes. High dilution disassembled these complexes over 5 µm into particles of ∼100 nm, and NaCl reduced the size of these particles. Immobilized water was detected in the complexes formed by particle flocculation.

RNA-seq based elucidation of mechanism underlying the protective effect of Huangshui polysaccharide on intestinal barrier injury in Caco-2 cells.

Polysaccharides from Huangshui (HS) have the function of antioxidant and immunoregulation, but its intestinal barrier protection activity and the underlying mechanism remains unclear. The present work mainly studied the intestinal barrier protection function and its potential molecular mechanism of a heteropolysaccharide named NLS-2 with a molecular weight of 51.9 kDa. NLS-2 reduced intestinal permeability by decreasing the content of inflammatory cytokines and increasing the expression of tight junction (TJ) protein in LPS-damaged Caco-2 cells, thus protecting the intestinal barrier function. RNA-seq results showed that the differentially expressed genes (DEGs) were mainly enriched in the signaling pathways of MAPK, Toll-like receptor, and NF-κB. Subsequent western blot validation experiments proved that NLS-2 could indeed inhibit the two pathways of MAPK and NF-κB by reducing the expression of TRL4, thereby down-regulating the release of downstream pro-inflammatory cytokines and playing the role of intestinal barrier protection. Collectively, NLS-2 has beneficial effects on LPS-damaged intestinal barrier by inhibiting the TRL4/MyD88/NF-κB and MAPK signaling pathways.

Structure elucidation and intestinal barrier protection of an α-D-glucan in Huangshui.

WLY-0, as an α-D-glucan with a molecular weight (Mw) of 11.12 kDa, was successfully isolated and purified from Huangshui (HS). The results of methylation and NMR indicated that the mainchain of WLY-0 was (1 â†’ 4)-α-D-glucan, with side chains linking at O-6. Meanwhile, the surface morphology characterization showed that WLY-0 had an irregular flake-like morphology with a rough and uneven surface and varies in sizes from nanometers to microns. Furthermore, WLY-0 relieved the increased paracellular permeability of FD4 and decreased TEER challenged by LPS, meanwhile inhibited the production of pro-inflammatory cytokines (TNF-α, IL-6, and IL-1ß) and up-regulated the expression of TJ protein (Occludin, Claudin-1, ZO-1, and JAM-A) in Caco-2 cells, so to improve the intestinal barrier function. Our findings about the structural characteristics and biological activities of WLY-0 provided a scientific foundation for the utilization of HS as a potent source of an effective adjuvant in intestinal barrier injury treatment.

Green tea polyphenols bind to soy proteins and decrease the activity of soybean trypsin inhibitors (STIs) in heated soymilk.

The interaction between epigallocatechin gallate (EGCG) and soy proteins at room temperature (25 °C) and after heating at 100 and 121 °C, and their effects on the inactivation of soybean trypsin inhibitors (STIs) in soymilk were investigated. The results of the nitroblue tetrazolium (NBT) staining assay showed that soy proteins can covalently bind to EGCG. The α/α' and A subunits in heated soymilk preferred to bind to EGCG because of their soluble state. More thiols were trapped when EGCG was added before thermal processing, and the free amino groups were depleted more with EGCG addition after heating. Circular dichroism and fluorescence spectroscopy showed that EGCG addition before or after heating induced different secondary and tertiary structural changes for soy proteins. The exposed aromatic amino acids preferred to react with EGCG before protein aggregation in the heating process. The random coil of soymilk proteins increased more when EGCG was added in soymilk after heating, resulting in more disordered structures in protein conformation. The binding between EGCG and soy proteins promoted protein aggregation, which was confirmed by the particle size distribution and gel electrophoresis. The trypsin and chymotrypsin inhibitory activity (TIA and CIA) in soymilk significantly reduced to 693 U mL-1 and 613 U mL-1, respectively, under the conditions of 2 mM EGCG addition after 100 °C heating for 10 min (p < 0.05). Consequently, the influence of EGCG on STI inactivation in soymilk only worked when EGCG was added after heating.

Effect of the Samples' Surface With Complex Microscopic Geometry on 3 × 3 Mueller Matrix Measurement of Tissue Bulks.

The clinical in vivo tissue bulks' surface is always coarse and shows a complex microscopic geometry which may affect the visual effect of polarization images and calculation of polarization parameters of the sample. To confirm whether this effect would cause identification difficulties and misjudgments on the target recognition when performed the polarization imaging based on 3 × 3 Mueller matrix measurement, cylindrical type and slope type physical models were used to study and analyze the effect of the surface with complex microscopic geometry on the polarization images. Then, clinical tumor bulk samples were used to interact with different sizes of patterns to simulate the different complex microscopic geometry and test the coarse surface effect on polarization images. Meanwhile, assessment parameters were defined to evaluate and confirm the variation between two polarization images quantitatively. The results showed that the polarization imaging of the sample surface with the complex microscopic geometry led to acceptable visual effect and limited quantitative variation on the value of polarization parameters and assessment parameters, and it caused no identification difficulties on target recognition, indicating that it is feasible to apply the polarization imaging based on 3 × 3 Mueller matrix measurement on clinical in vivo tissues with the complex microscopic geometry sample surface.

Protective Effects of Natural Polysaccharides on Intestinal Barrier Injury: A Review.

Owing to their minimal side effects and effective protection from oxidative stress, inflammation, and malignant growth, natural polysaccharides (NPs) are a potential adjuvant therapy for several diseases caused by intestinal barrier injury (IBI). More studies are accumulating on the protective effects of NPs with respect to IBI, but the underlying mechanisms remain unclear. Thus, this review aims to represent current studies that investigate the protective effects of NPs on IBI by directly maintaining intestinal epithelial barrier integrity (inhibiting oxidative stress, regulating inflammatory cytokine expression, and increasing tight junction protein expression) and indirectly regulating intestinal immunity and microbiota. Furthermore, the mechanisms underlying IBI development are briefly introduced, and the structure-activity relationships of polysaccharides with intestinal barrier protection effects are discussed. Potential developments and challenges associated with NPs exhibiting protective effects against IBI have also been highlighted to guide the application of NPs in the treatment of intestinal diseases caused by IBI.

Pepsin Diffusivity and In Vitro Gastric Digestion of Soymilk as Affected by Binding of Tea Polyphenols to Soy Proteins.

This study aimed to investigate the effect of tea polyphenol extract (TPE) on the in vitro gastric digestion of soymilk. Fluorescence recovery after photobleaching was applied to measure pepsin diffusivity in soymilk. The characteristics of soymilk digesta were evaluated by gel electrophoresis, degree of hydrolysis (DH), molecular weight distribution, free amino acid analysis, particle size, antioxidant capacity, and trypsin/chymotrypsin inhibitor activity (TIA/CIA). The binding between soy proteins and tea polyphenols could significantly impair in vitro gastric digestion of soymilk by decreasing pepsin diffusivity from 91.3 to 70.3 µm2/s and DH from 17.13 to 13.93% with 1.2 mg/g TPE addition. Soymilk with 0.6 mg/g TPE addition exhibited low TIA/CIA and a strong antioxidant capacity in gastric digesta, which might be good for the following intestinal digestion. A better understanding of the effect of polyphenol on the digestion of protein-based food may be beneficial to innovation in food manufacturing.

Heteroprotein Complex Coacervate Based on ß-Conglycinin and Lysozyme: Dynamic Protein Exchange, Thermodynamic Mechanism, and Lysozyme Activity.

Heteroprotein complex coacervate (HPCC) is a liquid-like protein concentrate produced by liquid-liquid phase separation. We revealed the protein dynamic exchange and thermodynamic mechanism of ß-conglycinin/lysozyme coacervate, and clarified the effect of HPCC on protein structure and activity. ß-conglycinin and lysozyme assembled into coacervate at pH 5.75-6.5 and assembled into amorphous precipitates at higher pH. As the pH dropped from 8 to 6, the number of binding sites of the complex decreased in half, and the desolvation degree corresponding to the entropy gain was greatly reduced, conducing to the formation of coacervates rather than precipitates. The coacervates achieved the unique dynamic exchange by exchanging proteins with the diluted phase, making the uniform distribution of proteins in coacervates. The lysozyme activity was completely retained in ß-conglycinin/lysozyme coacervates. These results proved that ß-conglycinin-based heteroprotein complex coacervate is a feasible method to encapsulate and enrich active proteins in a purely aqueous environment.

Physicochemical and Structural Characteristics of Soybean Protein Isolates Induced by Lipoxygenase-Catalyzed Linoleic Acid Oxidation during In Vitro Gastric Digestion.

The effects of oxidation on the gastric digestion properties of soybean protein isolates (SPIs) in a model of lipoxygenase (LOX)-catalyzed linoleic acid (LA) oxidation system and the multiscale structural characterization of SPI hydrolysate were investigated. Results indicated that the feature of SPI hydrolysate is dependent upon the degree of oxidation. Pepsin hydrolysis caused a red shift in fluorescence intensity and a reduction in surface hydrophobicity and diminished the particle size of SPI hydrolysate during gastric digestion. Compared with the control, mild oxidation was beneficial to protein unfolding and gastric digestibility, as manifested by minimal molecular weight (MW) distribution >50 kDa (32.34%) and smaller peptide fragments under scanning electron microscopy. However, severe oxidation brought about 39.47% loss of free amino acids. It was interesting to find that glycinin was more vulnerable to pepsin hydrolysis after oxidation as compared to the native SPI. Overall, the moderately oxidized SPI appeared to be digested to a greater extent.

Heteroprotein complex coacervation: Focus on experimental strategies to investigate structure formation as a function of intrinsic and external physicochemical parameters for food applications.

Proteins are important components of foods, because they are one of the essential food groups, they have many functional properties that are very useful for modifying the physicochemical and textural properties of processed foods and possess many biological activities that are beneficial to human health. The process of heteroprotein complex coacervation (HPCC) combines two or more proteins through long-range coulombic interaction and specific short-range forces, creating a liquid-liquid colloid, with highly concentrated protein in the droplet phase and much more diluted-protein in the bulk phase. Coacervates possess novel, modifiable, physicochemical characteristics, and often exhibit the combined biological activities of the protein components, which makes them applicable to formulated foods and encapsulation carriers. This review discusses research progress in the field of HPCC in three parts: (1) the basic and innovative experimental methods and simulation tools for understanding the physicochemical behavior of these heteroprotein supramolecular architectures; (2) the influence of environmental factors (pH, mixing ratio, salts, temperature, and formation time) and intrinsic factors (protein modifications, metal-binding, charge anisotropy, and polypeptide designs) on HPCC; (3) the potential applications of HPCC materials, such as encapsulation of nutraceuticals, nanogels, emulsion stabilization, and protein separation. The wide diversity of possible combinations of proteins with different properties, endows HPCC materials with great potential for development into highly-innovation functional food ingredients.

Structural characterization and immuno-stimulating activities of a novel polysaccharide from Huangshui, a byproduct of Chinese Baijiu.

Huangshui (HS), a byproduct of Baijiu, has been widely studied for the utilization of aromatic compounds and microorganisms. However, there is little information on the bioactive polysaccharides in HS. In this study, a novel complex polysaccharide (HSP-2) composed of mannose, glucose, galactose, arabinose, xylose, and rhamnose at approximate percentages of 53.0, 29.6, 11.5, 2.7, 2.1, and 1.0, respectively, was successfully extracted and purified from HS. The results of FT-IR, methylation analysis, and NMR showed that the backbone of HSP-2 was â†’ 2)-ß-D-Manp-(1 â†’ 2,6)-ß-D-Manp-(1 â†’ 6)-α-D-Glcp-(1 â†’ 4)-α-L-Rhap-(1 â†’ 3,4)-α-L-Rhap-(1→. In addition, HSP-2 showed significant immuno-stimulating effects via increasing the ROS and NO generation, and enhancing the pinocytic and phagocytic capacities of THP-1 cells in a dose-dependent manner. Meanwhile, HSP-2 treatment increased IFN-γ, TNF-α, IL-6 and IL-1ß secretion through activating the expression of the related mRNAs and proteins. These results will provide a molecular basis for immuno-stimulating effects of HSP-2 and lay a foundation for the potential application of HS in functional foods.

Effect of oxidation on the gel properties of porcine myofibrillar proteins and their binding abilities with selected flavour compounds.

In this work, the effect of oxidation induced by hydroxyl radicals on the binding abilities of myofibrillar protein (MP) gels to aldehydes and ketones and their relationship with MP gel properties were investigated. Mild oxidation (0-0.2 mM H2O2) could induce partial unfolding of MP, thus slightly increasing the salt solubility of MP and enhancing the hardness of MP gels. MP suffering a higher oxidative attack could undergo a reduction in water-holding capacity, with increased mobility of water in MP gels. Oxidation could make MP gel more disordered. The ability of oxidised MP gels to bind to flavours decreased as the carbon chain length of the flavour compound increased. MP oxidation only significantly affected the binding of MP gels to hexanal, heptanal, and 2-octanone, while other flavour compounds were not affected.

Isolation, purification, structure characterization of a novel glucan from Huangshui, a byproduct of Chinese Baijiu, and its immunomodulatory activity in LPS-stimulated THP-1 cells.

Huangshui (HS) has attracted considerable attention for the utilization of aroma compounds and microorganisms containing presently. However, little work has been done on biological polysaccharides in HS. In this study, a novel water-eluted HS polysaccharide, HSP-W, was identified as an α-D-glucan with a Mw of 166.00 kDa. It was consisted of a 1,4 linked α-D-Glcp backbone with the substitution at O-6 with 1,6-linked α-D-Glcp residue and non-reducing terminal of ß-Glc-1→ through monosaccharide composition, IR, methylation, and NMR analyses. SEM, AFM, and particle size distribution measurements showed that HSP-W had relatively clustered spherical shape with different sizes from nanoscale to micrometer. Additionally, HSP-W significantly induced NO and ROS production as well as the release of IL-1ß, IFN-γ, TNF-α, and IL-6, and upregulated pinocytic and phagocytic capacities of THP-1 cells. Meanwhile, HSP-W treatment markedly enhanced mRNA and protein expressions of these cytokines. HS probably has potential application as an immunostimulatory agent.