Thawed drip and its membrane-separated components: Role in retarding myofibrillar protein gel deterioration during freezing-thawing cycles.

Myofibrillar proteins are crucial for gel formation in processed meat products such as sausages and meat patties. Freeze-thaw cycles can alter protein properties, impacting gel stability and product quality. This study aims to investigate the potential of thawed drip and its membrane-separated components as potential antifreeze agents to retard denaturation, oxidation and gel deterioration of myofibrillar proteins during freezing-thawing cycles of pork patties. The thawed drip and its membrane-separated components of > 10 kDa and < 10 kDa, along with deionized water, were added to minced pork at 10 % mass fraction and subjected to increasing freeze-thaw cycles. Results showed that the addition of thawed drip and its membrane separation components inhibited denaturation and structural changes of myofibrillar proteins, evidenced by reduced surface hydrophobicity and carbonyl content, increased free sulfhydryl groups, protein solubility and α-helix, as compared to the deionized water group. Correspondingly, improved gel properties including water-holding capacity, textural parameters and denser network structure were observed with the addition of thawed drip and its membrane separation components. Denaturation and oxidation of myofibrillar proteins were positively correlated with gel deterioration during freezing-thawing cycles. We here propose a role of thawed drip and its membrane separation components as cryoprotectants against myofibrillar protein gel deterioration during freeze-thawing cycles.

Constructing myosin/high-density lipoprotein composite emulsions: Roles of pH on emulsification stability, rheological and structural properties.

The emulsification activity of myosin plays a significant role in affecting quality of emulsified meat products. High-density lipoprotein (HDL) possesses strong emulsification activity and stability due to its structural characteristics, suggesting potential for its utilization in developing functional emulsified meat products. In order to explore the effect of HDL addition on emulsification stability, rheological properties and structural features of myosin (MS) emulsions, HDL-MS emulsion was prepared by mixing soybean oil with isolated HDL and MS, with pH adjustments ranging from 3.0 to 11.0. The results found that emulsification activity and stability in two emulsion groups consistently improved as pH increased. Under identical pH, HDL-MS emulsion exhibited superior emulsification behavior as compared to MS emulsion. The HDL-MS emulsion under pH of 7.0-11.0 formed a viscoelastic protein layer at the interface, adsorbing more proteins and retarding oil droplet diffusion, leading to enhanced oxidative stability, compared to the MS emulsion. Raman spectroscopy analysis showed more flexible conformational changes in the HDL-MS emulsion. Microstructural observations corroborated these findings, showing a more uniform distribution of droplet sizes in the HDL-MS emulsion with smaller particle sizes. Overall, these determinations suggested that the addition of HDL enhanced the emulsification behavior of MS emulsions, and the composite emulsions demonstrated heightened responsiveness under alkaline conditions. This establishes a theoretical basis for the practical utilization of HDL in emulsified meat products.

Optimizing the formation of myosin/high-density lipoprotein composite gels: PH-dependent effects on heat-induced aggregation.

This study investigated impact of high-density lipoprotein (HDL) on thermal aggregation and gelling behavior of myosin in relation to varied pHs. Results revealed that HDL modified myosin structure before and after heating, with distinct effects observed at varied pH. Under pH 5.0, both myosin and HDL-MS exhibited larger aggregates and altered microstructure; at pH 7.0 and 9.0, HDL inhibited myosin aggregation, resulting in enhanced solubility, reduced turbidity and particle size. Comparative analysis of surface hydrophobicity, free sulfhydryl groups and secondary structure highlighted distinct thermal aggregation behavior between MS and HDL-MS, with the latter showing inhibitory effects under neutral or alkaline conditions. Gelation behavior was enhanced at pH 7.0 with maximum strength, hardness, water-holding capacity and rheological properties. Under acidic pH, excessive protein aggregation resulted in increased whiteness and rough microstructure with granular aggregates. Under alkaline pH, gel network structure was weaker, possibly due to higher thermal stability of protein molecules. Scanning electron microscopy revealed expanded HDL protein particles at pH 7.0, accounting for decreased gel strength and altered rheological properties compared with myosin gel. Overall, the results indicated a positive role of HDL at varied pH in regulating thermal aggregation of myosin and further impacting heat-induced gel characteristics.

Polyglycerol polyricinoleate and lecithin stabilized water in oil nanoemulsions for sugaring Beijing roast duck: Preparation, stability mechanisms and color improvement.

Traditional Beijing roast duck often suffers from uneven color and high sugar content after roasting. Water-in-oil (W/O) nanoemulsion is a promising alternative to replace high concentration of sugar solution used in sugaring process according to similarity-intermiscibility theory. Herein, 3% of xylose was embedded in the aqueous phase of W/O emulsion to replace 15% maltose solution. W/O emulsions with different ratios of lecithin (LEC) and polyglycerol polyricinoleate (PGPR) were constructed by high-speed homogenization and high-pressure homogenization. Distribution and penetration extent of solutions and emulsions through the duck skin, as well as the color uniformity of Beijing roast duck were analyzed. Emulsions with LEC:PGPR ratios of 1:3 and 2:2 had better stability. Stable interfacial film and spatial structure were important factors influencing emulsion stabilization. The stable W/O emulsions could more uniformly distribute onto the surface of duck skin and longitudinally penetrate through the skin than solutions.

Study on the Changes of Bone Calcium during the Fermentation of Bone Powders with Different Fermenters.

Two fermenters, Lactobacillus acidophilus (LA) and the active dry yellow wine yeast (HY), were utilized to ferment cattle bones in order to release calcium. The influences of fermenters and the fermentation process on the calcium release capacity, particle properties, morphology, and chemical composition of bone powders were assessed, and the underlying mechanism was discussed. The results showed that LA had a better capacity of acid production than yeast, and therefore released more calcium during the fermentation of bone powders. The released calcium in the fermentation broth mainly existed in the forms of free Ca2+ ions, organic acid-bound calcium and a small amount of calcium-peptide chelate. For bone powders, the fermentation induced swollen bone particles, increased particle size, and significant changes of the internal chemical structure. Therefore, fermentation has a great potential in the processing of bone-derived products, particularly to provide new ideas for the development of calcium supplement products.

Research advances of molecular docking and molecular dynamic simulation in recognizing interaction between muscle proteins and exogenous additives.

During storage and processing, muscle proteins, e.g. myosin and myoglobin, will inevitably undergo degeneration, which is thus accompanied by quality deterioration of muscle foods. Some exogenous additives have been widely used to interact with muscle proteins to stabilize the quality of muscle foods. Molecular docking and molecular dynamics simulation (MDS) are regarded as promising tools for recognizing dynamic molecular information at atomic level. Molecular docking and MDS can explore chemical bonds, specific binding sites, spatial structure changes, and binding energy between additives and muscle proteins. Development and workflow of molecular docking and MDS are systematically summarized in this review. Roles of molecular simulations are, for the first time, comprehensively discussed in recognizing the interaction details between muscle proteins and exogenous additives aimed for stabilizing color, texture, flavor, and other properties of muscle foods. Finally, research directions of molecular docking and MDS for improving the qualities of muscle foods are discussed.

Effects of W/O Nanoemulsion on Improving the Color Tone of Beijing Roast Duck.

Traditional Beijing roast duck is often brushed with a high concentration of maltose solution (15% w/v) and shows ununiform color after roasting. A novel W/O nanoemulsion was applied to improve the color tone of Beijing roast ducks and, meanwhile, reduced the amount of sugar. For the W/O emulsion, 3% (w/v) xylose solution as the aqueous phase, soybean oil as the oil phase, and polyglycerol polyricinoleate (PGPR) and whey protein isolate (WPI) as co-emulsifiers were fabricated by high-pressure homogenization. Particle size measurement by Zetasizer and stability analysis by Turbiscan stability analyzer showed that WPI as co-emulsifier and internal aqueous phase at pH 9 decreased the droplet size and improved the emulsion stability. In addition, by color difference evaluation, the W/O nanoemulsion improved the Maillard reaction degree and color tone of Beijing roast duck. The molecular structure and key composition of pigments on the surface of Beijing roast duck skins were also identified and characterized by UV-vis spectroscopy and UHPLC-MS. This study creatively offers theoretical guidance for increasing applications of W/O-nanoemulsion-based Maillard reaction in the roast food industry, especially for the development of reduced-sugar Beijing roast duck with uniform and desired color satisfying consumers' acceptance and marketability.

Liposomes as Delivery System for Applications in Meat Products.

In the meat industry, microbial contamination, and lipid and protein oxidation are important factors for quality deterioration. Although natural preservatives have been widely used in various meat products, their biological activities are often reduced due to their volatility, instability, and easy degradation. Liposomes as an amphiphilic delivery system can be used to encapsulate food active compounds, which can improve their stability, promote antibacterial and antioxidant effects and further extend the shelf life of meat products. In this review, we mainly introduce liposomes and methods of their preparation including conventional and advanced techniques. Meanwhile, the main current applications of liposomes and biopolymer-liposome hybrid systems in meat preservation are presented.

Allicin Promoted Reducing Effect of Garlic Powder through Acrylamide Formation Stage.

BACKGROUND: Acrylamide is formed during food heating and is neurotoxic to animals and potentially carcinogenic to humans. It is important to reduce acrylamide content during food processing. Researchers have suggested that garlic powder could reduce acrylamide content, but the key substance and acrylamide reduction pathway of garlic powder was unclear. METHODS: The inhibitory effect of garlic powder on acrylamide in asparagine/glucose solution and a fried potato model system were firstly evaluated. Furthermore, the effect of allicin on the amount of produced acrylamide in the asparagine/glucose solution model system and fried potatoes was studied with kinetic analysis. RESULTS: The freeze-dried garlic powder had a higher inhibition rate (41.0%) than oven-dried garlic powder (maximum inhibition rate was 37.3%), and allicin had a 71.3% attribution to the reduction of acrylamide content. Moreover, the inhibition rate of allicin had a nonlinear relationship with the addition level increase. The kinetic analysis indicated that garlic powder and allicin could reduce acrylamide content through the AA formation stage, but not the decomposition stage. CONCLUSIONS: Allicin was the key component of garlic powder in reducing acrylamide content during acrylamide formation stage. This research could provide a new method to reduce acrylamide content during food processing and expand the application area of garlic.

Sulforaphane Attenuates Nonalcoholic Fatty Liver Disease by Inhibiting Hepatic Steatosis and Apoptosis.

Nonalcoholic fatty liver disease (NAFLD) is characterized by lipotoxicity and ectopic lipid deposition within hepatocytes. Sulforaphane (SFA), an active compound used for inhibiting tumors, was found to have the potency to improve lipid metabolism. However, its molecular mechanisms on ameliorating NAFLD are still incompletely understood. This research evaluated if SFA could inhibit hepatic steatosis and apoptosis. The effects of SFA on cell viability, lipid accumulation, triglyceride (TG) contents, apoptosis, ceramide contents, and reactive oxygen species (ROS) levels were analyzed in palmitic acid (PA)-treated HepG2 cells and high-fat diet (HFD)-fed mice. The related molecular mechanisms were further explored in hepatocytes. The results showed SFA alleviated lipid accumulation and regulated AMPK/SREBP1c/FAS signaling pathway in PA-stressed HepG2 cells. In addition, SFA alleviated PA-mediated apoptosis, downregulated the expressions of cleaved caspase 3, as well as reduced ceramide contents and ROS levels. Moreover, SFA treatment reduced HFD-induced body weight gain, alleviated insulin resistance, decreased serum TG, total cholesterol (TC), and alanine aminotransferase (ALT) levels, and prevented lipid deposition and apoptosis in the liver. This study showed SFA suppressed lipid deposition and apoptosis both in vitro and in vivo, indicating that SFA may be a potential candidate for preventing and treating NAFLD.

Human Milk Oligosaccharides Activate Epidermal Growth Factor Receptor and Protect Against Hypoxia-Induced Injuries in the Mouse Intestinal Epithelium and Caco2 Cells.

BACKGROUND: Hypoxia-induced intestinal barrier injuries lead to necrotizing enterocolitis (NEC). Although NEC in preterm neonates is preventable by human milk oligosaccharides (HMOs), the underlying mechanism remains unknown. OBJECTIVE: To reveal the role and mechanism of HMOs in protecting against hypoxia-induced injuries in intestinal epithelium of neonatal mice and cultured Caco2 cells. METHODS: NEC was induced by hypoxia and cold stress. Seventy C57BL/C pups (7-d-old) were divided into 5 groups and fed maternal breast milk (BM), formula alone (FF), or the formula added with HMOs at 5 (LHMO), 10 (MHMO), or 20 mg/mL (HHMO) for 3 d. Ileal hypoxia inducible factor 1α (HIF1α) and cleaved Caspase 3 were determined, along with staining for Ki-67 protein to labeled proliferative cells. In vitro, adherent Caco2 cells (undifferentiated, passage 14) were treated with HMOs, galacto-oligosaccharides, fructo-oligosaccharides, or mixed oligosaccharides at 10 mg/mL for 1 d exposed to 1% O2. Cell proliferation and apoptosis, along with phosphorylated epidermal growth factor receptor (P-EGFR) and 38KD MAPK (P-P38), were assayed in differentiated or undifferentiated Caco2 cells. RESULTS: Compared with the FF-fed mice, those fed MHMO and HHMO had 52% lower (P < 0.05) NEC scores, 60-80% greater (P < 0.05) KI67-positive cell numbers, and 56-71% decreases (P < 0.05) in ileal HIF1α and cleaved Caspase 3 (56-71%). Compared with those untreated, the HMO-treated Caco2 cells displayed 60% greater (P < 0.05) proliferative activity and 19% lower (P < 0.05) apoptotic cells after the hypoxia exposure. The HMO treatment led to 58% or 10-fold increases (P < 0.05) of P-EGFR and 48-89% decreases (P < 0.05) of P-P38 in either differentiated or undifferentiated Caco2 cells compared with the controls. CONCLUSION: Supplementing HMOs at 10-20 mg/mL into the formula for neonatal mice or media for Caco2 cells conferred protection against the hypoxia-induced injuries. The protection in the Caco2 cells was associated with an activation of EGFR.

Liensinine Inhibits Beige Adipocytes Recovering to white Adipocytes through Blocking Mitophagy Flux In Vitro and In Vivo.

Promoting white-to-beige adipocyte transition is a promising approach for obesity treatment. Although Liensinine (Lie), a kind of isoquinoline alkaloid, has been reported to affect white-to-beige adipocyte transition, its effects on inhibiting beige adipocytes recovering to white adipocytes and maintaining the characteristics of beige adipocyte remain unclear. Therefore, we explored the effects and underlying mechanism of Lie on beige adipocyte maintenance in vitro and in vivo. Here, we first demonstrated that after white adipocytes turned to beige adipocytes by rosiglitazone (Rosi) stimuli, beige adipocytes gradually lost their characteristics and returned to white adipocytes again once Rosi was withdrawn. We found that Lie retained high levels of uncoupling protein 1 (UCP1) and mitochondrial oxidative phosphorylation complex I, II, III, IV and V (COX I-V), oxygen consumption rate (OCR) after Rosi withdrawal. In addition, after Rosi withdrawal, the beige-to-white adipocyte transition was coupled to mitophagy, while Lie inhibited mitophagy flux by promoting the accumulation of pro-cathepsin B (pro-CTSB), pro-cathepsin D (pro-CTSD) and pro-cathepsin L (pro-CTSL), ultimately maintaining the beige adipocytes characteristics in vitro. Moreover, through blocking mitophagy flux, Lie significantly retained the molecular characteristics of beige adipocyte, reduced body weight gain rate and enhanced energy expenditure after stimuli withdrawal in vivo. Together, our data showed that Lie inhibited lysosomal cathepsin activity by promoting the accumulation of pro-CTSB, pro-CTSD and pro-CTSL, which subsequently inhibited mitophagy flux, and ultimately inhibited the beige adipocytes recovering to white adipocytes and maintained the characteristics of beige adipocyte after stimuli withdrawal. In conclusion, by blocking lysosome-mediated mitophagy, Lie inhibits beige adipocytes recovering to white adipocytes and may be a potential candidate for preventing high fat diet induced obesity.

The hepatic-targeted, resveratrol loaded nanoparticles for relief of high fat diet-induced nonalcoholic fatty liver disease.

Nonalcoholic fatty liver disease (NAFLD) is the early stage of many metabolic syndromes. The intervention of NAFLD can prevent its further development into severe metabolic syndromes. Given the inefficiency and side effects of chemical drugs for treating NAFLD, the hepatic-targeted nanocarriers loaded with bioactive compounds may offer a more effective and acceptable strategy for eliminating NAFLD. Here we developed hepatic-targeted oxidized starch-lysozyme (OSL) nanocarriers to specifically deliver resveratrol (Res) to liver tissue in order to maximize its therapeutic efficiency. The hepatic targeting was achieved using covalently conjugated galactose (Gal), which is recognized by the asialoglycoprotein receptors specifically expressed in hepatocytes. In steatotic HepG2 cell model, treatment with hepatic-targeted Gal-OSL/Res nanocarriers enhanced the cellular Res uptake and anti-lipogenesis capabilities, and effectively decreased triglyceride accumulation by modulating AMP-activated protein kinase (AMPK)/silent information regulation 2 homolog 1(SIRT1)/fatty acid synthase (FAS)/sterol regulatory element-binding protein-1c (SREBP1c) signaling pathway. In mice, Gal-OSL increased Res delivery into liver tissues and increased their hepatic effective concentration in liver. Most importantly, Gal-OSL/Res nanocarriers effectively reversed NAFLD and recovered hepatic insulin sensitivity of NAFLD mice to the healthy state. Furthermore, Gal-OSL/Res efficiently ameliorated lipid deposition and insulin resistance by modulating AMPK/SIRT1/FAS/SREBP1c signaling pathway and downregulated insulin receptor substrate-1 (IRS-1) phosphorylation at serine 307 in liver. These findings suggested that the hepatic-targeted Gal-OSL nanocarriers delivering Res could potentially serve as a safe and promising platform for NAFLD and other liver related diseases.

Sulforaphane Prevents Hepatic Insulin Resistance by Blocking Serine Palmitoyltransferase 3-Mediated Ceramide Biosynthesis.

Sulforaphane (SFA), a naturally active isothiocyanate compound from cruciferous vegetables used in clinical trials for cancer treatment, was found to possess potency to alleviate insulin resistance. But its underlying molecular mechanisms are still incompletely understood. In this study, we assessed whether SFA could improve insulin sensitivity and glucose homeostasis both in vitro and in vivo by regulating ceramide production. The effects of SFA on glucose metabolism and expression levels of key proteins in the hepatic insulin signaling pathway were evaluated in insulin-resistant human hepatic carcinoma HepG2 cells. The results showed that SFA dose-dependently increased glucose uptake and intracellular glycogen content by regulating the insulin receptor substrate 1 (IRS-1)/protein kinase B (Akt) signaling pathway in insulin-resistant HepG2 cells. SFA also reduced ceramide contents and downregulated transcription of ceramide-related genes. In addition, knockdown of serine palmitoyltransferase 3 (SPTLC3) in HepG2 cells prevented ceramide accumulation and alleviated insulin resistance. Moreover, SFA treatment improved glucose tolerance and insulin sensitivity, inhibited SPTLC3 expression and hepatic ceramide production and reduced hepatic triglyceride content in vivo. We conclude that SFA recovers glucose homeostasis and improves insulin sensitivity by blocking ceramide biosynthesis through modulating SPTLC3, indicating that SFA may be a potential candidate for prevention and amelioration of hepatic insulin resistance via a ceramide-dependent mechanism.

Resveratrol metabolites ameliorate insulin resistance in HepG2 hepatocytes by modulating IRS-1/AMPK.

Resveratrol (trans-3,5,4'-trihydroxystilbene, RSV), a naturally occurring biologically active polyphenol has been observed to induce numerous beneficial effects in diabetic animals and humans. However, its protective effects are somewhat controversial due to low bioavailability and rapid clearance rate. Therefore, we in this study have tried to investigate if its main metabolites, RSV-3-O-glucuronide (R3G) and RSV-4-O-glucuronide (R4G) could ameliorate insulin resistance, similar to RSV in insulin-resistant HepG2 cells. Herein, we first established an insulin-resistant cell model by treating HepG2 cells with 1 × 10-6 mol L-1 insulin for 24 h. Subsequently, the effects of R3G and R4G on insulin resistance inhibition were evaluated in HepG2 cells. Interestingly, our data indicated that R3G and R4G treatment improved cellular glucose uptake and glycogen synthesis contents, and blocked generation of intracellular reactive oxygen species (ROS). Additionally, R3G and R4G also modulated insulin signaling and improved insulin sensitivity by modulating the IRS-1/AMPK signaling pathway. Taken together, our data provided a significant new insight into the effects and molecular mechanism of R3G and R4G on ameliorating insulin resistance in HepG2 cells. Overall, our data supported the hypothesis that despite low bioavailability in vivo, RSV biological effects could be mediated through its metabolites.

Sulforaphene inhibits triple negative breast cancer through activating tumor suppressor Egr1.

Sulforaphene (SFE, 4-methylsufinyl-3-butenyl isothiocyanate) is a member of isothiocyanates, which is derived from radish seeds. It has shown that multiple isothiocyanates, such as sulforaphane, can effectively inhibit cancer cell proliferation in vitro and in vivo. However, it is still largely unknown if SFE could impact breast cancer. In this study, we investigated the anticancer effects of SFE on triple negative breast cancer (TNBC) via a series of in vitro and in vivo assays. We found that SFE can significantly inhibit cell proliferation in multiple TNBC cell lines through inducing G2/M phase arrest as well as cell apoptosis. Nude mice xenograft assays support the anti-TNBC role of SFE in vivo. Interestingly, SFE can repress expression of cyclinB1, Cdc2, and phosphorylated Cdc2, and, then, induced G2/M phase arrest of TNBC cells. To identify SFE target genes, we detected genome-wide gene expression changes through gene expression profiling and observed 27 upregulated and 18 downregulated genes in MDA-MB-453 cells treated with SFE. Among these genes, Egr1 was successfully validated as a consistently activated gene after SFE treatment in TNBC MDA-MB-453 and MDA-MB-436 cells. Egr1 overexpression inhibited proliferation of TNBC cells. However, Egr1 knockdown using siRNAs significantly promoted TNBC cell growth, indicating the tumor suppressor nature of Egr1. In sum, we for the first time found that SFE might be a potential anti-TNBC natural compound and its antiproliferation effects might be mediated by tumor suppressor Egr1.