高压处理对碎牛肉重组特性的影响

为提高低值碎牛肉的利用率,改善其重组特性,将碎牛肉制成牛肉肠经高压处理,对其蒸煮损失率、非压出水分、保水性、黏结性和微观结构进行研究。通过单因素试验得出:碎牛肉的蒸煮损失率随着压力的增大、保压时间的延长和保压温度的增加均呈先降后升趋势,非压出水分、保水性和黏结性呈先升后降趋势,并都在400 MPa,15 min,20℃附近达到最佳值;通过响应面(SEM)法分别得到高压改善碎牛肉蒸煮损失率(500 MPa,25 min,35℃)、非压出水分(431 MPa,15℃,18.6 min)、保水性(500 MPa,25 min,35℃)和黏结性(383 MPa,35℃,25 min)的最适处理条件,并对其四项指标综合考虑进行最优化求解,求得高压提高碎牛肉重组特性的最佳处理条件为469 MPa、35℃、25 min;经研究发现,该条件下处理后的碎牛肉各项指标明显优于对照组,且微观结构也更加规则有序。由此可知:适当的高压处理可以有效改善碎牛肉的重组特性,具有较好的应用前景。     

Effects of Connective Tissue on Algin Restructured Beef

Different levels of connective tissues were examined in algin/calcium gel restructured beef tenderloin, riblifter and foreshank products. Foreshank meat, which contained a high level of collagen (4.83%), formulated with algin/calcium gel ingredients, exhibited relatively strong bind in the raw and cooked state. Addition of 5–10% undenatured or 5% denatured connective tissue to algin/calcium restructured riblifter meat resulted in products of acceptable bind and sensory quality. However, beef riblifter formulations containing 10% added denatured connective tissue had greater (P<0.05) discoloration and lower (p<0.05) bind than the other added connective tissue plus algin/calcium treatments. Algin/calcium binder improves quality of restructured meat formulated with increased concentrations of connective tissue.     

Effects of Wheat Gluten, Soy Isolate and Flavorings on Properties of Restructured Beef Steaks

Restructured beef steaks were made in triplicate to contain the following ingredients; meat only, meat + vital wheat gluten (VWG) and meat + isolated soy protein (ISP). In addition, each treatment was made with and without flavorings (0.44% sodium chloride, 0.25% sodium tripolyphosphate and 0.31% hydrolyzed vegetable protein). Off-flavor scores were not different (P > 0.05) between meat and meat + VWG steaks made without flavorings; however, steaks made with meat + ISP alone had the highest (P < 0.05) off-flavor score. AU products made with flavorings were more cohesive, juicier, and required more effort to fragment than those made without flavorings. Instron rheological values increased (not significant among all comparisons) when flavorings were used. Steaks made with VWG or ISP were not different from each other in overall desirability scores but neither of these treatments (with or without flavorings) were as desirable as controls.     

Effects of Flake Size on Textural and Cooking Properties of Restructured Beef and Pork Steaks

Flaked and formed beef and pork steaks were manufactured using eleven different Comitrol cutting heads selected to give a wide range in flake size. Data from texture profile panel, Instron and cooking studies were collected. As flake size increased, visually detected fi-brousness, first bite hardness, cohesiveness of the chewed mass, number of chews required for swallowing, amount of connective tissue detected by sensory panel and shear force all increased, while uniformity of the chewed mass decreased. Textural properties in beef and pork steaks were affected in a similar manner by flake size. Thickness of the flake particle was as important as width of the flake particle in affecting texture.     

Effect of Phosphates on the Functional Properties of Restructured Beef Rolls: The Role of pH, Ionic Strength, and Phosphate Type

Combinations of sodium chloride and five different phosphates were used to study the effect of phosphate type (chain lengths: 1.0–12.8), ionic strength (0.15–0.43), and pH (5.50–6.35) on the binding ability (cook yield and tensile strength) of restructured beef rolls. The results showed that binding ability increased linearly with increasing ionic strength and pH until a maximum value was reached and then plateaued; approximately 80% of the increase in binding ability was due to the increase in ionic strength and pH. Above an ionic strength of 0.15, the polyphosphates (chain length > 1.0) produced synergistic increases in binding ability with increasing ionic strength. The extent of the synergistic effect decreased linearly as the chain length of the phosphate increased.     

Effects of Hot-Boning and Particle Thickness on Restructured Beef Steaks

Restructured steaks were made using hot-boned or aged beef made from sliced particles (2.5 mm or 5.0 mm thick). Beef slices were formed to make restructured steaks. The steaks were evaluated for cooking characteristics, textural properties and sensory attributes. Restructured steaks made from hot-boned beef were generally considered less tender and received lower texture desirability, flavor desirability and overall palatability ratings as compared to steaks made from aged beef. Restructured steaks made from larger meat slices (5.0 mm) were less tender and received lower texture desirability ratings than restructured steaks made with thinner slices (2.5 mm).     

Thermal Properties of Restructured Beef Products at Different Isothermal Temperatures

Thermal properties and components of restructured beef products formulated with five binders (0.5–5.0%) were determined after heating to 35, 45, 55, or 65°C. Binders were: isolated soy protein, sodium caseinate, waxy modified corn starch, carrageenan, and oat flour. Water losses were greater when no binders were used until 65°C was attained. Density was influenced by both temperature and binder; specific heat was influenced by temperature; and thermal conductivity and thermal diffusivity were influenced by binder. All thermal properties correlated with water and/or protein contents of restructured beef products.     

基于高光谱和超声成像技术的原切与合成调理牛排鉴别

针对市场上存在合成调理牛排冒充原切售卖的现象,研究利用高光谱和超声成像技术对它们进行鉴别的方法.分别采集原切与合成调理牛排的高光谱和超声图像信息,利用灰度共生矩阵法提取图像的纹理特征值,分别建立线性判别分析、K最邻近(K-nearest neighbor,KNN)、反向传播人工神经网络和极限学习机(extreme le...     

Glucose and Internal Cooking Temperature Effects on Low Fat, Pre- and Post-Rigor, Restructured Beef Roasts

Muscles were excised pre-rigor (hot-boned, HB) or post-rigor (conventionally boned, CB), chunked, and were subjected to four ingredient treatments: (SPE) 2% NaCl, 0.5% NaCl, 0.5% phosphate, 2% glucose (SP 2% NaCl, 0.5% phosphate (SG) 2% NaCl, 2% glucose and (PG) 0.5% phosphate, 2% glucose to produce low fat, restructured, beef roasts, which were cooked to an internal temperature of 63 or 93°C. Addition of glucose to a salt and phosphate (LEM-O-FOS¹) ingredient treatment as well as cooking to 93°C helped maintain low warmed-over flavor (WOF) scores and kept thiobarbituric acid values below threshold (< 1.0) while maintaining desirable consumer acceptability scores.     

Effects of Mechanically Separated Beef with Various Chloride Salts in Restructured Beef Steaks

The effects of various chloride salts (NaCl, MgCl₂, KCl or 65% NaCl + 35% KCl) in combination with mechanically separated beef (MSB at 0, 10 or 20%) on the quality of restructured steaks formulated from bullock chucks were determined. As level of MSB increased, objectionable connective tissue, flavor desirability and overall palatability decreased and off-flavors increased. The development of oxidative rancidity during frozen storage was not affected by MSB level and MSB had little effect on textural traits. NaCl and NaCl + KCl treated steaks received superior flavor and overall palatability ratings over steaks containing MgCl₂ or KCl. Oxidative rancidity developed faster in steaks containing NaCl than the other salt types. Partial replacement (35%) of NaCl with KCl resulted in restructured steaks with sensory properties equal to and storage life superior to steaks with NaCl alone.     

Effect of Phosphate Type and Concentration, Salt Level and Method of Preparation on Binding in Restructured Beef Rolls

The effect of combinations of phosphate type [tetrasodium pyrophosphate (PP), sodium tripolyphosphate (TPP), sodium tetrapolyphosphate (TTPP), and sodium-hexametaphosphate(HMP)], phosohate concentration (0.125%-0.500%). and salt level (0.6%-2.0%) on the binding in restructured beef rolls was studied. The rolls were prepared either with or without a homogenate that contained all the added salts. Preparation method had little effect on binding. The effectiveness of the phosphates was: PP > TPP > TTPP > HMP. Changes in binding produced by varying phosphate type, phosphate concentration and salt level could be explained in terms of changes in ionic strength and pH. Between 90% and 96% of the variation in binding could be explained in terms of these two variables.     

Effects of Tumbling at Various Speeds on Some Characteristics of Restructured Cured Beef

The effects of different tumbling speeds (5, 10, 15, and 20 rpm) during 12 hr intermittent tumbling (10 min/hr) on the characteristics of a restructured cured beef product were studied. There were no differences (P>0.05) among the various treatment means for yield, Hunter color scores, voids between chunks of meat, handling-ability or Allo-Kramer shear values. Meat tumbled at 15 and 20 rpm had higher (P<0.05) Instron values than the meat tumbled at 5 or 10 ‘rpm. However, 20 rpm produced more (P<0.05) extracted protein on the meat surface than 5 rpm. In summary, 5, 10, and 15 rpm produced satisfactory products, although 15 rpm had greater binding ability.     

Functional, Sensory, and Microbiological Properties of Restructured Beef and Emu Steaks

Beef and emu steaks were restructured with 5% fibrinogen/0.25% thrombin (F), 0.5% algin/0.5% calcium lactate (A), or 0.5% phosphate/1.5% salt (P). P and A treatments had higher cooked binding strengths and cook yields than the F treatments (P < 0.05). The pH and cook yields of restructured emu were higher than beef (P < 0.05). Binding strength of emu was lower than beef in all binding systems (P < 0.05). F solution had an aerobic plate count (APC) of 39,000/g and increased the microbial count in restructured emu steaks from 940 to 7500/g (P < 0.05). Cooking to 60°C reduced APC to < 250/g (P < 0.05) with progressively greater bacterial kill after cooking to 66°C or 75°C.     

Effects of Trimming and Added Connective Tissue on Compositional, Physical and Sensory Properties of Restructured, Pre-cooked Beef Roasts

Restructured beef roasts were prepared using trimmed (intermediate or extensive) and chunked (kidney plate or hand knife) beef shoulder clods with varying levels (0, 10, 20 or 30%) of added connective tissue (flaked with Comitrol^R). Intact beef top rounds (control) and all restructured roasts were water cooked to 62.8°C internal temperature. Increasing connective tissue increased (P<0.05) tenderness and fat of restructured products with no deleterious effect (P>0.05) on product bind. Addition of 30% connective tissue decreased (P<0.05) juiciness and overall acceptability of the products; however, products with addition of 10% or 20% connective tissue were acceptable. Sensory data indicated restructured roasts were as acceptable as intact top rounds.     

Effects of Blade Tenderization and Proteolytic Enzymes on Restructured Steaks from Beef Bullock Chucks

Three studies were conducted to determine the effects of blade tenderization (BT), fungal protease, ficin and papain on sensory ratings, textural properties and frozen storage life of restructured steaks from beef bullock chuck. Neither blade tenderizing of chuck muscles prior to incorporating it into restructured steaks nor the use of 0.05% or 0.10% fungal protease had an effect on the amount of connective tissue or textural properties of the cooked product. The addition of 0.10% fungal protease to restructured steaks increased the frozen storage life of the restructured steaks from 82 days (0%) to 149 days and over 157 days for 0.05%. The addition of ficin and papain had a detrimental effect on texture, flavor and overall satisfaction ratings. The methods tested in the present study are not suitable treatments for reducing the amount of detectable connective tissue in restructured steaks from beef bullock chucks.     

Formulation of a Pasteurized Restructured Beef Product

Restructured beef products (18 – 20% fat) were formulated and pasteurized to provide storage stability at 4.4°C. An optimal formulation was determined with a full factorial experiment having 4 levels of whey and rennet-treated sodium caseinate blend and 3 levels of texturized soy protein. Response surfaces for product yield, fat retention and bind strength were calculated utilizing regression procedures. Maximum product yield of 92% was predicted by the optimization and subsequently achieved. An observed fat retention of 92% was lower than the predicted value. Over 16 wk of storage at 4.4°C, no aerobic or anaerobic bacterial growth was observed and TBA values remained very low.     

粘结剂使用条件对重组牛肉品质的影响

为了改善重组牛肉的品质特征,本实验采用转谷氨酰胺酶(TG)和酪蛋白酸钠(SC)组成的粘结剂对重组牛肉进行品质改性,研究粘结剂的最佳反应条件。通过采用单因素试验方法,研究粘结剂反应时间(1、2、3、4、5、6h)、反应温度(1、4、7、10℃)、反应压强(2、3、4、5、6N/m2)对重组牛肉粘结强度和剪切力的影响,比较不同反应时间、反应温度及反应压强条件下重组牛肉的品质差异。结果表明：通过对加工过程中粘结剂反应时间、反应温度和反应压强3个条件的研究,重组牛肉的解冻损失、蒸煮损失、硬度、弹性、咀嚼性等物理性质存在显著差异,实验得出的最佳反应条件为：反应时间3h,反应温度4℃,反应压强4N/m2。     

重组牛肉图像识别模型的比较研究

以重组牛肉为研究对象,基于机器视觉技术构建3种深度残差网络(deep residual network,ResNet)模型(ResNet-50、ResNet-101、ResNet-152)用于识别重组牛肉,同时应用VGG-16视觉几何群网络模型、支持向量机模型以及LeNet-5卷积神经网络模型,比较分析ResNet模型的识别准确率和响应时间。采集并经过图像预处理后共得到6 168张样品图像作为实验样本,随机选取其中的4 936张作为训练集,剩余1 232张作为测试集。结果表明:3种ResNet模型(ResNet-50、ResNet-101、ResNet-152)识别速率较快,准确率高,均可以有效识别重组牛肉,且卷积层越多,准确率越高,其中ResNet-50模型识别准确率达到较高水平,且测试时间仅需0.45 s,能够准确、快速地识别重组牛肉。     

消费者对重组调理牛排态度的调查研究

近年来,国内肉类企业不断加大重组调理牛排的生产量,但是关于消费者对重组调理牛排的态度鲜有报 道。本研究通过网络调研与实地调研相结合的方法调研我国消费者对重组调理牛排的认知与态度。结果表明：产品 质量是消费者购买重组调理牛排的首要考虑因素;相比于其他购买方式,消费者更愿意在超市等实体店购买重组调 理牛排;月收入6 000 元以下的消费者更倾向于购买重组调理牛排,重组调理牛排的市场定位应为中低端产品。     

食用胶对重组牛肉加工特性的影响

将转谷氨酰胺酶和酪蛋白酸钠作为重组牛肉使用的黏合剂,添加量为原料牛肉质量的1.2%。在此基础上,分别添加0.3%(m/m)的卡拉胶、亚麻胶等多种食用胶,通过测定黏结性、色差、解冻损失、蒸煮损失、尺寸变化、剪切力、质构来说明食用胶对重组牛肉加工特性的影响。研究结果表明,亚麻胶和黄原胶都显著降低了重组牛肉的黏结性(P ＜ 0.05),且成片性不好。卡拉胶能增加a* 值,δ- 葡萄糖酸内酯(GDL)和卡拉胶的复合胶却降低了a* 值。添加结冷胶、亚麻胶和黄原胶均降低重组肉的解冻损失和蒸煮损失,而且添加亚麻胶和黄原胶的重组牛肉嫩度最大。