Reducing harmful substances produced during food processing has been a global focus of attention. Basic amino acids, widely reported as promising substitutes for NaCl, have demonstrated the ability to inhibit the formation of harmful substances. This review systematically summarizes the inhibitory mechanisms of basic amino acids, which include: competitive inhibition of Maillard precursors and protein binding sites; scavenging reactive dicarbonyl intermediates; direct elimination; pH modulation to alter reaction pathways; chelating metal ions and scavenging free radicals to suppress lipid oxidation. Besides, applicable research methods (such as quantum chemical computation analysis, molecular docking, and lipidomics) are proposed for application in mechanism research to deeply analyze the mechanism by which basic amino acids inhibit harmful substances. A systematic understanding of these mechanisms will provide critical insights for mitigating the formation of hazardous compounds in food processing.

This paper aimed to investigate the effects of ultrasound-assisted L-lysine treatment on meat quality and myofibrillar proteins (MPs) properties of pork longissimus dorsi during postmortem aging. The results revealed that the L-lysine (Lys) and/or ultrasound treatment significantly increased (p < 0.05) the water-holding capacity and tenderness of the pork during postmortem aging, while the ultrasound-assisted Lys treatment had the lowest cooking loss, pressurization loss, Warner-Bratzler shear force, and hardness. In addition, L-lysine and/or ultrasound treatment increased (p < 0.05) pH value, T21, and myofibrillar fragmentation index, while the ultrasound-assisted Lys treatment had the highest value. Meanwhile, the protein solubility was increased with Lys and/or ultrasound treatment during postmortem aging, and ultrasound-assisted Lys treatment had the highest solubility, reaching 88.19%, 92.98%, and 91.73% at 0, 1, and 3 days, respectively. The result of protein conformational characteristics showed that Lys and/or ultrasound treatment caused the unfolding of the α-helix structure, resulting in the exposure of more hydrophobic amino acids and buried sulfhydryl groups, ultimately enhancing MPs solubility. In summary, ultrasound-assisted Lys treatment altered the structure of MPs, resulting in the enhancement of the water-holding capacity and tenderness of the pork. PRACTICAL APPLICATION: This study showed that ultrasound-assisted L-lysine (Lys) treatment could enhance the water-holding capacity and tenderness of pork during postmortem aging. The results might provide a reference for the application of ultrasound-assisted Lys treatment on the improvement of pork meat quality. To facilitate practical applications in production, the development of medium and large-sized ultrasound equipment for conducting small-scale and pilot experiments is crucial for future research.

The imidazoquinoline type (IQ-type) is recognized as the most mutagenic activity in heterocyclic amines currently, and closely associated with a variety of cancers and neurodegenerative diseases of human. The precursors of IQ-type HAs are free amino acids, reducing sugars, and creatine/creatinine, and these precursors can undergo a series of chemical reactions at high temperature, and intermediate products such as free radicals and reactive carbonyl compounds are formed, which are the basis for the formation of IQ-type HAs. The exogenous substances added to the meat products during the thermal processing affected the IQ-type HAs formation to varying degrees. There are three main action mechanisms of the exogenous substances inhibiting IQ-type HAs, including competitive inhibition mechanism of precursors, free radical scavenging mechanisms, and active carbonyl compounds capturing mechanism. This article focuses on the formation process of IQ-type HAs and the inhibitory mechanism of exogenous substances, and clarified the reaction pathway of IQ-type HAs generation, and elaborated the action mechanism of exogenous substances inhibiting the formation of IQ-type HAs in detail. This paper provides theoretical guidance for effectively controlling the IQ-type HAs formation during the thermal processing of meat products.

As one of the key rate limiting enzymes in glycolysis process, the characteristics of pyruvate kinase (PK) play an important role in regulating the muscle quality. Given the close relationship between kinase phosphorylation level and its stability, the present study investigated the impact of exogenous l-histidine (l-his) on PK phosphorylation and activity at 1% NaCl level in the early postmortem. An incubation system was also constructed and the results showed that the introduction of 0.06% l-his caused the dephosphorylation and increased the activity of PK at 1% NaCl. Compared with 1% NaCl treatment, three differential phosphorylation sites were produced when l-his was introduced. The PK secondary structure was shift from order to disorder, leading to a distinct degradation. This present study provided us with inspiration that meat quality could be improved by exogenous l-his at early postmortem under low NaCl conditions.

The high sodium content in meat products poses health risks to consumers and does not align with modern green and healthy living standards. Current strategies for directly reducing the sodium content in meat products are limited by their negative impact on the sensory or quality attributes of the products. In recent years, there has been great interest in applying ultrasound technology to reduce sodium content. This paper discusses the advantages and disadvantages of current mainstream strategies for reducing the sodium content in meat products, as well as the potential mechanisms by which ultrasound-assisted marination improves the quality of low-salt meat products. The main findings indicate that ultrasound, through its cavitation and mechanical effects, facilitates the transition of proteins from stable insoluble aggregates to stable soluble complexes, exposing more hydrophilic groups and, thus, enhancing protein solubility. At the same time, ultrasound promotes a greater number of proteins to participate in the formation of interfacial layers, thereby increasing emulsifying activity. Furthermore, ultrasound treatment promotes the interaction between proteins and water, leading to partial unfolding of protein chains, which allows polar residues to more readily capture water in the gel, thereby improving the water-holding capacity of the gel. These effects will contribute to the formation of high-quality low-salt meat products. However, variations in the frequency, intensity, and duration of ultrasound treatment can lead to differing effects on the quality improvement of low-salt meat products.

The prerigor salting effect is known to provide superior meat processing quality. Based on the urgent need for low salt meat products, the present study was undertaken to evaluate the prerigor salting effect when basic amino acids were introduced at 1% NaCl level. Ground chicken breast meat was salted with NaCl and basic amino acids at 30 min, 60 min, and 90 min postmortem for prerigor treatments. Compared to the 1% NaCl (w/w) treatment, the introduction of 0.06% basic amino acids (w/w) in the prerigor significantly led to an increase in myofibril fragmentation, myofibrillar protein solubility, emulsion activity, storage modulus change rate, gel water holding capacity and hardness (P < 0.05). Furthermore, smaller and more uniformly sized droplets were produced in emulsion by basic amino acids. Individual basic amino acids had different prerigor salting effects, and it was indicated that basic amino acids could play a positive role in the prerigor salting effect when NaCl was reduced.

With the increasing consumption of mutton and the frequent occurrence of related food safety problems, the demand for mutton traceability and authentication technologies has become a hot spot in the current society. At present,there have been reports on on the traceability and identification of mutton. Stable isotope technology, mineral element fingerprinting, near-infrared spectroscopy, DNA molecular marker-based traceability technology, fatty acid-based traceability and identification technology, and flavor compound-based traceability and identification technology have been widely used in traceability and identification research. However, with the continuous development of these technologies,some urgent problems have been exposed. Based on the current research data and literature, this paper summarizes and discusses the advantages and disadvantages of mutton traceability and identification technologies, analyzes the problems existing in the current technical research, and puts forward suggestions and solutions, in order to provide theoretical support for further research.

The influences of citrus aurantium juice (CAJ) immersion and resonant vibration assisted by the immersion on the instrumental properties, cooking loss, vibrated weight gain of supraspinatus (SS), quadriceps femoris (QF) and longissimus thoracis (LT) muscles from yak carcasses were investigated, as well as the collagen characteristics, pyridinoline cross-links, myofibrillar MFI. In the circumstance of CAJ concentration of 1% and the ratio of meat to liquid 1:2, the shear force of SS and QF were significantly decreased by 20.3% and 20.2% (P < 0.05), and cooking loss significantly decreased by 17% and 23% (P < 0.05), respectively, compared to the control. At this combination of the concentration and the ratio of meat to liquid, the total collagen contents of SS and QF were significantly decreased by 23% and 18%, the collagen heat solubility 1.4 times and 1.5 times that of the raw meat (P < 0.05), respectively. At the pH value closed to the pI of myofibrillar proteins, the immersion assisted resonance with the amplitude of 2 mm and vibration duration of 1 h made the LT shear force to be decreased by 12%, 7.8% and 10.9% than the control, 0.5 h and 1.5 h of vibration duration (P < 0.05), respectively. Furthermore, the ultrastructure in LT gave rise to obvious alteration due to the CAJ immersion and its assisted resonance. The present study has confirmed again that the resonance does cause meat tenderization by means of destroying the integrity of the M-band structure in sarcomere.

本文主要回答了"品牌是什么"这一根本性问题,揭示了品牌的哲学本质,并用系统哲学原理分析了品牌的形成过程.本文认为:品牌是消费者与产品互动的关系性存在.一个产品标记符号经系统自组织的方式涌现成为凝结着消费者忠诚的品牌.而产品标志符号在这一交互过程中不是简单的消费者对产品认识的螺旋式上升而是经系统整体优化后形成更高层次结构成为品牌.品牌的建立、延伸、迁移和衰退会随消费者认识的深化而变化.本文对品牌本质的揭示为品牌概念体系的发展奠定了基础.

During the conversion of muscle to meat, a series of biochemical changes are required for meat aging. Protein phosphorylation, a dynamic regulation mechanism of proteins, regulates almost every major biological process, and is one of the extensive post-translational modifications in the biological world. Therefore, studying the relationship between protein phosphorylation and postmortem muscle is helpful to the development of the meat industry. This article begins with an introduction to protein phosphorylation, discusses the technical progress in phosphorylated protein detection, summarizes the proteins that are phosphorylated in muscle after slaughter and the influential factors of protein phosphorylation, and reviews the effect of protein phosphorylation on meat quality attributes such as tenderness, color and water-holding capacity. The application of salts and amino acids in improving postmortem meat quality is reviewed and future research directions are also proposed.

Heterocyclic amines (HAs) are a class of toxic compounds with strong teratogenic and carcinogenic activities which are produced during thermal processing of meat products. Three types of HAs, including 2-amino-3-methyl-imidazo[4,5-f]-quinoline (IQ) and 2-amino-3,4-dimethyl-imidazo[4,5-f]-quinoline (MeIQ), 2-amino-1-methyl-6-phenylimidazo[4,5-b]-pyridine (PhIP), and 1-methyl-9H-pyrido[3,4-b]indole (harmane) and 9H-pyrido[3,4-b]indole (norharman), are common and widely distributed in heat-processed meat products. This article briefly analyzes the formation pathways and mechanisms of these HAs, elucidates the inhibitory mechanism of exogenous plant polyphenols on their formation, and clarifies the structure-activity relationship of polyphenol compounds for the inhibition of their formation. This review will provide theoretical guidance for the effective application of plant polyphenols to control the formation of HAs in heat-processed meat products.

The effects of HYP (10, 50, and 250 μM/g protein) on the physicochemical and gel properties of myofibrillar proteins (MPs) at different NaCl concentrations under oxidative stress were explored. The incorporation of HYP significantly reduced carbonyl content and decreased the loss of free amine groups in a dose-dependent manner, regardless of NaCl concentration. In addition, HYP induced a dose-dependent decrement in total sulfhydryl content regardless of NaCl concentration, which might result from the formation of thiol-quinone adducts via Michael addition. The surface hydrophobicity was significantly increased with HYP addition. Nevertheless, compared with samples treated with 50 μM/g HYP, 250 μM/g HYP caused a significant decrease in surface hydrophobicity, which might be due to the increase in the extent of MPs unfolding and the concomitant aggregation of MPs by hydrophobic interaction. Furthermore, HYP also showed a dose-dependent increment in the water-holding capacity (WHC) and gel strength of MPs gels, which might be due to more orderly crosslinks via fibrous filaments at 0.2 M NaCl and more regular and lamellar structures with smaller and more homogeneous pores at 0.6 M NaCl. In summary, HYP reduced the oxidation-mediated changes of physicochemical characteristics, preventing the oxidative damage of MPs and reinforcing the ordered crosslinks of MPs-MPs and MPs-HYP during thermal gelation, ultimately resulting in a better gel quality. These results provide a theoretical support for the practical application of HYP as a natural antioxidant in gel-type meat products.

To analyze systematically the effects of marinated in eggs on edible quality of different meats during cooking of several traditional Chinese dishes, marinated in whole egg or egg white, and different egg white addition were chosen to analyze the effects on the edible quality of pork patties, beef patties, and lamb patties. The results showed that, at the addition of 10% and marinated for 30 min, when marinated in egg white, the water content of the pork patties and lamb patties were significantly increased (P<0.05), while the cooking loss, shear forces and hardness values were significantly reduced (P<0.05), indicated that the edible quality of the two meat loaves were effectively improved. However, marinated in whole egg was more suitable for the beef patties, which to a certain extent, improved its edible quality. The effects of different egg white additions on edible qualities of three meat loaves were different. When marinated for 30 min, 10% of egg white addition was suitable for the pork patties and lamb patties, while 5% was more suitable for beef patties. Under these conditions, the water holding capacity of the meat loaves was excellent, and the tenderness, color, and texture characteristics were preferred, which were suitable for promotion to use as a best addition condition for egg white marinating in the daily cooking process. The present study provides the theoretical support for the egg marinating conditions before cooking in traditional Chinese meat dishes.

In this study, we investigated the stability of oil-in-water emulsions prepared using eggplant flesh pulp (EFP) as natural emulsifier. The effects of time and environmental stresses on the stability of emulsions with different EFP concentrations were evaluated using the creaming indices (CIs), particle sizes, and zeta potentials of the emulsions. The emulsions with EFP concentrations of up to 1.50% remained stable for at least 90 days. The CIs, mean particle diameters (MPDs ]d3,2 ]), and zeta potentials of the emulsions with adequate EFP concentrations remained unchanged in the pH range of 3-9. Microstructure observations revealed that flocculation occurred for the emulsion with an EFP concentration of 1.50% at pH 3, whereas flocculation and coalescence occurred in the emulsion with a low EFP concentration of 0.50%. Upon increasing the concentration of NaCl from 0 to 0.5 M, the MPDs (d3,2 ) of the emulsions with EFP concentrations of 1.00% and 1.50% remained nearly constant (57 and 48 µm, respectively). Moreover, the MPDs (d3,2 ) and zeta potentials of the emulsions with EFP concentrations of 1.00% and 1.50% did not change significantly upon increasing temperature from 4 to 100°C. Hence, the emulsions with adequate EFP concentrations presented long storage times and were stable under various environmental stresses. Our results indicate that EFP is an effective and inexpensive emulsifier that can confer emulsions long-term storage stability and good resistance to environmental stresses. PRACTICAL APPLICATION: Eggplant, which is a common crop, is a rich source of natural materials. In this study, eggplant flesh pulp (EFP) was prepared via mechanical homogenization and its emulsifying properties for oil-in-water emulsions were evaluated. Our results demonstrated that the EFP-stabilized oil-in-water emulsions featured long storage times and were stable under environmental stresses (pH, ionic strength, and temperature). These properties render EFP-stabilized emulsions suitable as delivery systems for encapsulating and releasing nonpolar active ingredients in food products.

Background: Due to the high NaCl contents of meat products, a reduction in their sodium levels is an ongoing focus for researchers, enterprises, and consumers. Current strategies for salt reduction are limited by their negative impact on the sensory or textural qualities of meat and fish products.Scope and approach: Basic amino acids could be salt substitutes for satisfying consumer demand and fulfilling the industrial drive to provide meat and fish products with desirable textures. In this review, we present an overview of earlier published studies on the influence of basic amino acids on the muscle protein processing properties (physicochemical, gel, and emulsion characteristics) and quality (proteolysis, lipolysis, protein oxidation, lipid oxidation, sensory, and textual properties) and the underlying mechanism. In addition, we have explored the future possibilities of using basic amino acids in meat and fish products.Key findings and conclusions: Basic amino acids are promising substitutes for NaCl in meat processing because of several advantageous properties, especially at low NaCl level. Basic amino acids in combination with chloride salts, yeast extract, and other salts have been evaluated as substitutes for NaCl. It is proposed that sensory enhancement by the addition of basic amino acids can be explored from the view of taste-taste interactions. Further studies are required to determine the mechanism underlying the positive effects of basic amino acids on muscle protein characteristics, to expand their fields of application, and to understand their functionality in terms of post-mortem metabolism.

为明确GB 2760-2014《食品安全国家标准食品添加剂使用标准》中允许添加至热加工肉制品使用的不同抗氧化剂的体外抗氧化活性与其抑制肉制品蛋白质氧化和脂肪氧化能力之间的关系,分别测定8种抗氧化剂的体外抗氧化活性(1,1-二苯基-2-三硝基苯肼(1,1-diphenyl-2-picrylhydrazyl,DPPH)自由基清除能力和还原力),同时将其添加至热加工肉制品中,研究其对肉制品硫代巴比妥酸反应产物(thiobarbituric acid reactive substance,TBARS)值、羰基含量和巯基含量的影响,分析其对肉制品脂肪氧化和蛋白质氧化的影响.结果 表明,迷迭香酸(rosmarinci acid,RA)、茶多酚(tea polyphenols,TP)、茶黄素(theaflavins,TF)和鼠尾草酸(carnosic acid,CA)处理组的总多酚含量、DPPH自由基清除能力及还原力均显著高于甘草提取物(glycyrrhiza extract,GE)、竹叶提取物(extract of bamboo leaves,BL)、植酸钠(sodium phytate,SP)和山梨酸钾(potassium sorbate,PS)处理组;在烤肉饼和炸肉饼中,不同抗氧化剂对不同种类肉制品蛋白质氧化和脂肪氧化的改善作用有较大差异,其中BL是对6种热加工肉制品相对最有效的抗氧化剂,而TF适用于降低烤鸡肉饼和烤牛肉饼的蛋白质氧化和脂肪氧化程度,TP则对改善烤牛肉饼和烤猪肉饼的蛋白质氧化和脂肪氧化更有效,SP是炸鸡肉饼和炸牛肉饼蛋白质氧化和脂肪氧化的有效抑制剂,CA则更适用于对炸牛肉饼和炸猪肉饼氧化的改善.综上,具有较强体外抗氧化活性的抗氧化剂(RA、TP、TF和CA)在热加工肉制品中不一定表现出良好的抑制肉制品蛋白质氧化和脂肪氧化的能力,而具有较弱的体外抗氧化能力的抗氧化剂则可能具有较强的抑制热加工肉制品蛋白质氧化和脂肪氧化的活性(BL和SP).这表明抗氧化剂的体外抗氧化活性与其改善热加工肉制品氧化稳定性的能力之间并不一定存在显著的相关性.

嫩度一直是消费者购买肉制品时最关注的品质指标之一,肉品质的控制与嫩化技术密切相关.随着科学技术的发展,物理嫩化技术以快速、经济、非热、绿色和节能的优势而广受关注.本文主要概述脉冲电场、超声波和高压加工等物理嫩化技术在以改善肉嫩度为目的的同时对肉品安全性、氧化稳定性及色泽方面产生的影响,并通过分析相关的因素提出改善措施.

SummaryThis study investigated the effects of l‐lysine (Lys) and l‐histidine (His) on the oxidative characteristics and gel properties of porcine myofibrillar proteins (MP). Results showed that Lys and His had a strong ferrous ion‐chelating ability and hydroxyl radical‐scavenging activity. Moreover, Lys and His inhibited the protein carbonyl formation and MP aggregation at 0.2 M and 0.6 M NaCl, respectively, in a dose‐dependent manner. Furthermore, 2 and 4 mg mL−1 Lys and His decreased the oxidation‐induced loss of the tertiary structure of MP accompanied by the lower surface hydrophobicity. The water‐holding capacity and gel strength of MP gels increased with increasing Lys and His concentrations due to more regular and lamellar structures with smaller and homogeneous pores at 0.6 M NaCl and more orderly crosslinking via fibrous filament at 0.2 M NaCl. In summary, Lys and His chelated the ferrous ions and scavenged hydroxyl radicals, decreased the oxidation‐induced physicochemical changes, thus preventing oxidative damage during the formation of a three‐dimensional gel network, which resulted in better gel quality.

SummaryThe present work examined the impact of L‐Arginine (Arg) on the emulsifying properties, interfacial behaviour and conformational characteristics of myofibrillar proteins (MPs) at high (0.6 m) and low (0.15 m) salt concentration to maintain good emulsifying properties of MPs at low salt concentration. The data indicated that Arg increased the emulsifying activity index/emulsion stability index (EAI/ESI) and decreased the CI and droplet size of emulsions regardless of salt concentration. Raman spectra revealed that the α‐helix content decreased from 60.30% to 51.26% at high salt concentration, and from 60.20% to 54.82% at low salt concentration in the presence of Arg. In addition, MPs treated with Arg exhibited a higher interfacial pressure and more rapidly diffusion to the oil surface. Meanwhile, Arg increased the interfacial protein loading. The results demonstrated that Arg caused the unfolding of MPs, promoting the adsorption of proteins and decreasing the interfacial tension, ultimately improving the stability of emulsions at low salt concentration.

2-amino-1-methyl-6-phenylimidazole[4,5- b ]pyridine (PhIP) is one of the most abundant Heterocyclic amines (HAs) in meat products. Zanthoxylum bungeanum Maxim. leaf (ZML) extract has been shown to be rich in polyphenols, which are gaining increasing interest as efficient tools for inhibiting the formation of HAs. In the present work, the effects of ZML extract, major polyphenols, chlorogenic acid, hyperoside and quercitrin on the formation of PhIP in both roast beef patties and chemical model systems were investigated. UPLC-MS showed that ZML extract and those three polyphenols effectively inhibited PhIP formation. Additionally, GC-MS analysis showed that those three polyphenols significantly reduced the content of phenylacetaldehyde in the model systems, a key intermediate involved in PhIP formation. The subsequent UPLC-MS and TOF-MS/MS analysis found that hyperoside and quercitrin reacted with phenyacetaldehyde to form those four adducts, 8-C-( E -Phenylethenyl)hyperoside, 6-C-( E -Phenylethenyl)hyperoside, 8-C-( E -Phenylethenyl)quercitrin and 6-C-( E -Phenylethenyl)quercitrin, respectively. The results revealed that hyperoside and quercitrin could trap phenylacetaldehyde to form adducts, thereby, retarding the reaction of phenylacetaldehyde and creatinine, blocking the generation of PhIP.