氧化对兔肉肌原纤维蛋白结构、乳化性和凝胶性的影响研究

为探讨氧化对兔肉肌原纤维蛋白结构的氧化修饰及对肌原纤维蛋白乳化性质和凝胶质构特性的影响,本文利用0~10.0 mmol/L 2,2'-盐酸脒基丙烷(2,2'-azobis(2-amidinopropane)dihydrochloride,AAPH)热解产生的烷过氧自由基对兔肉肌原纤维蛋白进行氧化处理。结果表明,随着AAPH浓度的增加,兔肉肌原纤维蛋白游离巯基含量、内源性荧光强度和蛋白乳化稳定性不断减小,而羰基含量、二聚酪氨酸含量、蛋白粒径、乳化活性显著增加(P<0.05),表面疏水性则呈现先增后减再增的趋势。聚丙烯酰胺凝胶电泳(polyacrylamide gel electrophoresis,SDS-PAGE)结果显示,低浓度AAPH(0~1.0 mmol/L)和高浓度(10.0 mmol/L)分别诱导了蛋白的聚集和裂解,这些结构的改变引起了肌原纤维蛋白凝胶性质的改变。适度的氧化改性(AAPH 0~1.0 mmol/L)能提高兔肉肌原纤维蛋白凝胶的质构特性,而进一步氧化(AAPH 1.0~10.0 mmol/L)则显著降低了凝胶的性能(P<0.05)。因此,烷过氧自由基的氧化修饰能显著影响兔肉肌原纤维蛋白的结构和乳化凝胶性质(P<0.05)。     

Comparison of lipid and protein oxidation,total iron content and fatty acid profile of conventional and organic pork

The aim of the research was to compare differences in lipid and protein oxidation, total iron content and fatty acid profile in pork loin obtained from organic and conventionally reared pigs. The samples of organic meat were taken from breeding certified by the polish certifying body according to the Council Regulation (EC) no 834/2007 on organic production and labelling of organic products. The meat samples were examined at the following times post‐mortem: 2, 4, 7 days. Measurements of lipid oxidation showed that the organic meat samples were characterised by lower TBARS values during whole storage period (0.78–0.81 mg kg^?1) compared with those of conventional system production (0.95–0.99 mg kg^?1). Results of protein oxidation measurements of the organic meat sample were significantly lower (0.43 nmol mg^?1 protein) at the beginning of experiment than those for the conventional meat sample (0.66 nmol mg^?1 protein). It was also indicated that the production system had no effect on iron content and myoglobin oxidation during storage. In conclusion, obtained results pointed out that the organic pig meat was characterised by higher lipid stability during the whole storage time compared with meat from conventional production system.     

Extrusion Process Parameters, Sensory Characteristics, and Structural Properties of a High Moisture Soy Protein Meat Analog

ABSTRACT: Soy protein isolate and wheat starch at 9:1 ratio were extruded at 60%, 65%, and 70% moisture contents and 138, 149 and 160 °C cooking temperatures. The results indicated that moisture content was a more important factor than cooking temperature for both extrusion process parameters and product sensory characteristics. Extrusion at a lower moisture content resulted in a higher product temperature and higher die pressure. The resultant products were tougher, chewier, and more cohesive and had a more layered and fibrous structure. Water absorption capacity increased with both higher extrusion moisture and higher cooking temperature.     

The effects of different levels of non-fat dry milk and whey powder on emulsion capacity and stability of beef, turkey and chicken meats

The effects of different concentrations (0.00, 0.25, 0.50%) of either non‐fat dry milk (NFDM) or whey powder (WP) on emulsion capacity (EC) and emulsion stability (ES) of beef, chicken and turkey meats were studied by using a computer model system. The effects of meats types and additives (NFDM and WP) on EC and ES were found to be statistically significant (P < 0.01). Of the meats, chicken had the highest and beef the lowest values of EC and ES. When using different concentrations of WP and NFDM, 0.25% WP and 0.50% NFDM had the highest values of EC. The effect of different concentrations (0.25 and 0.50%) of WP was insignificant on ES; however, the effects of different concentrations (0.0, 0.25 and 0.50%) of NFDM were significant on ES.     

传统肉类替代品——人造肉的研究进展

人造肉主要分为两种:一种是通过动物干细胞合成的人造动物肉;一种是通过植物蛋白及其他植物性成分合成的植物性肉。从能源角度讲,人造肉能够减少饲养牲畜时所产生的能耗。从温室效应角度考虑,人造肉能够减少温室气体的排放,减缓全球变暖的压力。而从营养角度讲,人造动物肉能够提供传统屠宰肉类似的氨基酸、脂肪及维生素等;植物性肉主要由植物蛋白合成,同样能够给人体补充大量蛋白质。因此将人造肉作为传统肉类的替代品,不仅能够提供应有的营养,还能给环境、能源等带来可持续性增益。但人造肉目前仍存在较多的技术、伦理道德以及安全等方面问题。本文介绍了两种人造肉的主要制作方法,综述了人们目前对人造肉的认识以及态度,最后总结了人造肉在未来市场可能会遇见的挑战,以期为我国人造肉行业的发展提供参考。     

The determination of soya and meat protein in raw and processed meat products by specific peptide analysis. An evaluation

The detection and measurement of characteristic peptides formed on enzymatic hydrolysis of soya protein products, meats and offals is described. Samples were heated at 120°C for 3h prior to digestion with trypsin overnight, and the resultant peptide mixtures passed through an Amicon ultrafiltration membrane. After concentration the ultrafiltrates were analysed by ion exchange chromatography on Aminex A5 resin. Peptides were detected by post-column reaction with ninhydrin. Characteristic peaks designated SP 2 and MP 1 were seen in chromatograms of digests of soya protein isolate and beef respectively, and these peaks were well resolved in beef and soya protein isolate mixtures. The SP 2 peak was shown to contain peptides derived from soya 11 S globulin. The soya protein and beef contents of a series of mixtures of freeze-dried, defatted beef and soya protein isolate were determined by measurement of the SP 2 and MP 1 peaks respectively. Soya protein content could be determined within 2% of the true value over the range 30–70% soya protein isolate and beef content could be determined within 5% of the true value in the range 20–100% beef. Analysis of five soya protein isolates, four soya protein concentrates, six soya flours and 13 textured soya products indicated considerable interproduct variation in the yield of SP 2. The MP 1 peak was seen in a range of meats, both cooked and raw. It was also present in digests of offals which contained smooth or striated muscle but not in ‘non-muscle’ offals. The protein origin of the MP 1 peak was not established but the yield appeared lower in meat products which had been heated during manufacture than in those which had received no such treatment. Analysis of a series of laboratory prepared canned and heated pork and soya protein isolate mixtures enabled the pork content to be determined to within 8% of the true value, 2% soya protein isolate could be detected but not quantified accurately.     

人造肉生产工艺及其研究进展

人造肉作为一种创新的替代品,被广泛认为是解决肉类供应紧缺、环境影响和动物福利等问题的有效方式。根据制备技术的不同,人造肉可以分为植物蛋白肉、细胞培养肉和微生物蛋白肉3种类型。文章探讨了植物蛋白肉、细胞培养肉和微生物蛋白肉的生产工艺和感官品质提升工艺,分析了各自的技术优势和存在的挑战,并对未来人造肉产品的发展趋势进行了展望。     

中国人造植物肉产业的发展现状、驱动机制与前景预测

随着社会发展进步,健康饮食、绿色可持续发展等观念受到广泛认同。相比于传统肉,植物基蛋白肉具有营养丰富、环境友好且节约生产要素等优势,成为当下的研究热点。本研究简要梳理了植物基蛋白肉近年来的国内外研究现状、发展历程,系统介绍了植物基蛋白肉的原料组成、挤压技术以及质量评价方法。最后,总结了植物基蛋白肉研究中现存的主要问题,并结合实际研究进展提出展望。未来,应以深入研究植物基蛋白肉产品的外观、风味、质地等感官特性为主,同时兼顾营养和安全性。高湿挤压技术作为未来发展方向,除调整含水量、挤压温度和其他工艺参数外,还需重点关注冷却模具的改进。     

动植物源蛋白体外消化产物结构性质及ACE抑制活性

为揭示动植物源蛋白对于血压调节功能上的差异是否由蛋白肽的血管紧张素转化酶（angiotensin conversion enzyme,ACE）抑制活性所引起,动植物蛋白经体外消化后,对蛋白肽的ACE活性抑制进行研究。采用胃蛋白酶-胰蛋白酶两步消化法,水解植物蛋白（大米、燕麦、大豆、豌豆）、红肉蛋白（猪肉、牛肉）和白肉蛋白（鸡肉）。测定所获蛋白肽的水解度、分子质量分布、氨基酸组成及其ACE抑制率。结果表明,随着蛋白质水解度的增加和分子质量的减小,3类蛋白消化产物的ACE活性抑制率均相应增大。其中,植物蛋白消化产物ACE抑制率最高（60.41%）,红肉蛋白最低（40.13%）。对蛋白质消化产物的氨基酸组成进行分析,结果表明,植物蛋白和白肉蛋白消化产物的疏水性氨基酸含量均显著高于红肉蛋白。3类蛋白中消化产物的疏水性氨基酸含量越高,则ACE抑制活性越高,说明疏水性氨基酸含量高可能是植物蛋白肽具有高的ACE抑制活性的主要原因之一。     

大豆营养仿肉制品的开发研究

大豆营养仿肉制品是以大豆蛋白为原料,辅以大豆植物油,添加调味料和香辛料,经过类似肉制品加工方法进行加工。但这类产品不采用畜禽肉为原料,不属于肉制品,只是模仿肉制品的组织结构并赋予肉制品的风味,按照肉制品来命名,如"大豆维也纳香肠"或"素维也纳香肠"、"大豆牛肉火腿"或"素牛肉火腿",产品具有高蛋白、不含动物脂肪、低胆固醇特点,以满足人们健康需求以及越来越多素食者的需要。     

植物蛋白与乳蛋白在肉制品加工中的应用

植物蛋白和乳蛋白由于具有较高的营养价值和优良的功能特性,作为食品配料被广泛应用于肉类工业。本文简要介绍了肉制品加工中使用的植物蛋白与乳蛋白、植物蛋白与乳蛋白在肉制品加工中应用的主要功能特性及植物蛋白与乳蛋白在肉制品加工中的作用。     

生产类群、性别及包装方式对冷藏牦牛肉肌浆蛋白氧化的影响

为了探讨冷藏条件下牦牛肉肌浆蛋白的氧化规律,本实验通过羰基含量、巯基含量、表面疏水性、紫外吸收光谱及十二烷基硫酸钠-聚丙烯酰胺凝胶电泳法研究了普通包装和真空包装方式下不同生产类群的公、母牦牛肉的肌浆蛋白氧化特性。结果表明：随冷藏时间的延长,两种包装的肌浆蛋白羰基含量呈波浪式上升趋势（P＜0.05）,总巯基含量下降;普通包装组表面疏水性上升（P＜0.05）,真空包装组表面疏水性先上升后下降;同一包装方式的不同生产类群之间肌浆蛋白羰基、总巯基含量及表面疏水性均有显著差异（P＜0.05）;公、母牦牛肉之间肌浆蛋白羰基、总巯基及疏水性差异均不显著（P＞0.05）。两种包装的肌浆蛋白紫外吸收光谱的二阶导数光谱在冷藏第3天谱图改变最明显。随着氧化的进行,肌浆蛋白分子质量降低,所有蛋白条带均有不同程度的弱化,普通包装组肌浆蛋白降解程度大于真空包装;相同冷藏时间,2 种包装方式的不同生产类群及性别的牦牛肉的肌浆蛋白紫外吸收谱图及电泳图趋于一致。该研究认为,在冷藏过程中,肌浆蛋白的蛋白氧化与包装方式、生产类群密切相关,与牦牛的性别无关。     

Physicochemical and structural changes of myofibrillar proteins in muscle foods during thawing: Occurrence,consequences, evidence,and implications

Myofibrillar protein (MP) endows muscle foods with texture and important functional properties, such as water-holding capacity (WHC) and emulsifying and gel-forming abilities. However, thawing deteriorates the physicochemical and structural properties of MPs, significantly affecting the WHC, texture, flavor, and nutritional value of muscle foods. Thawing-induced physicochemical and structural changes in MPs need further investigation and consideration in the scientific development of muscle foods. In this study, we reviewed the literature for the thawing effects on the physicochemical and structural characters of MPs to identify potential associations between MPs and the quality of muscle-based foods. Physicochemical and structural changes of MPs in muscle foods occur because of physical changes during thawing and microenvironmental changes, including heat transfer and phase transformation, moisture activation and migration, microbial activation, and alterations in pH and ionic strength. These changes are not only essential inducements for changes in spatial conformation, surface hydrophobicity, solubility, Ca²⁺-ATPase activity, intermolecular interaction, gel properties, and emulsifying properties of MPs but also factors causing MP oxidation, characterized by thiols, carbonyl compounds, free amino groups, dityrosine content, cross-linking, and MP aggregates. Additionally, the WHC, texture, flavor, and nutritional value of muscle foods are closely related to MPs. This review encourages additional work to explore the potential of tempering techniques, as well as the synergistic effects of traditional and innovative thawing technologies, in reducing the oxidation and denaturation of MPs and maintaining the quality of muscle foods.     

Restructured, Shelf-stable Steaks from Shark Meat Gel

A gelation-dependent process to prepare a convenient food product from shark meat was developed. Pieces of skinned and deboned shark were soaked overnight in cold water, drained and the washed meat was homogenized in an equal amount of cold water. The homogenate was converted into a gel by lowering its pH to 3.5 using acetic acid. Hardness of the gel was dependent upon its moisture content. The gel spread in stainless-steel tray was steamed for 15 min, cooled, cut into steaks and aerobically packaged in polyethylene pouches. The product was stable against microbial growth when stored for 2 mo at 10 °C or 4 wk at ambient temperature, although ambient temperature storage for more than a week resulted in yellowing of the steamed gel. The 10 °C-stored steaks were deacidified and salted by dipping in an aqueous solution of 50 g/L each of NaHCO₃ and NaCl for 15 min before frying in vegetable oil. The product was acceptable in terms of texture and flavour by a panel of experienced tasters.     

Emulsion Stability and Water Uptake Ability of Chicken Breast Muscle Proteins as Affected by Microbial Transglutaminase

ABSTRACT: Using response surface methodology, the effect of microbial transglutaminase (TG) concentration and incubation time (IT) after emulsification, but before creaming, on the functional properties of chicken meat proteins was examined. TG improved the stability of emulsions (ES) made with a high-salt chicken meat protein extract, although TG did not significantly affect the amount of protein incorporated into the emulsion cream layer. IT significantly enhanced ES when incubated at 40 °C, but not at 4 °C. TG increased the water uptake ability (WUA) of both chicken muscle and chicken muscle protein extract incubated at 40 °C and 4 °C. Similarly, TG increased the protein and water content of the pellet formed in the WUA test. TG therefore appears to be a useful method to enhance the stability and yield of meat batters.     

肉蛋白烹调氧化及其对肉品与人体健康的影响

烹调加工会加剧蛋白质氧化,导致蛋白质结构、理化性质等发生变化,从而影响其功能特性与营养价值。本文介绍了肉类烹调过程中蛋白质氧化机制、表现形式,探讨了其对肉类感官品质与营养价值的影响及对人体健康的潜在危害,最后进行总结与展望。      

Biochemical and microbiological studies on kawal,a meat substitute derived by fermentation of cassia obtusifolia leaves

Biochemical and microbiological changes during the fermentation of leaves of the tropical legume, Cassia obtusifolia, in the preparation of the traditional Sudanese food, kawal, are reported. The microflora during fermentation were dominated by two bacteria, Bacillus subtilis and Propionibacterium sp. Other species present included Lactobacillus plantarum, Staphylococcus sciuri and two yeasts. No marked inter-special successional pattern was observed during fermentation. Sun-dried kawal possessed a mean crude protein content of 26.2% indicating negligible loss of N during fermentation. The overall chemical score of kawal protein was 73 with lysine as the most limiting amino acid. The main fermentation products were volatile fatty acids (VFA) principally n-butyric and acetic acids although propionic and isobutyric acids were also present. Total VFA content averaged 15% at the end of fermentation but fell to 10% during sun-drying. Lactic acid concentrations remained low throughout fermentation, the final product containing only 0.2% of this compound. Accumulation of ammonia-N closely paralleled VFA formation and similarly declined sharply in concentration during sun-drying. The major alcohols formed during fermentation were n-propanol and n-butanol which attained a maximum combined concentration of 3% although disappearing during the drying process. The insignificant change in pH during fermentation was ascribed to the buffering effect of the high calcium content of the leaves. Changes in chemical composition noted during sun-drying indicated that this process involved not only dehydration but secondary microbial action.     

冻藏肉及其制品中蛋白氧化的研究进展

冻藏是肉及其制品最重要的贮藏方式,可有效抑制微生物生长繁殖及酶促反应,从而延长其货架期.然而,肉及其制品在长期冻藏过程中不可避免地发生品质下降.除冰晶、嗜冷微生物、干耗、脂肪氧化等因素外,蛋白氧化在品质劣化中所发挥的作用受到关注.本文综述肉及其制品中蛋白氧化的发生机制、氧化结果以及检测方法;冻藏过程中影响蛋白氧化的因素...     

乳清蛋白的功能特性及其在肉类制品中的应用

近年来乳清蛋白以其优秀的蛋白质来源及其良好的功能特性受到人们的广泛关注。本文主要介绍了乳清蛋白的性制和功能,重点综述其在肉类加工制品中应用。     

天然肉味香精

综述了肉味前体物质,导致肉挥发性香气产生的反应,肉香气的成分分类,天然肉味香精的生产等方面,着重叙述了肉味前体物质,Ｍａｉｌａｒｄ反应和分别以ＨＶＰ、肉蛋白质酶水解物为基料的天然肉味香精的生产,并对天然肉味香精的发展前景进行了探讨。