现代化热剔骨工艺研究进展

阐述了现代化热剔骨工艺的特点及热剔骨工艺中的肉品成熟嫩化过程,同时介绍了国际热剔骨工艺研究领域及肉类成熟领域的研究进展,对这一领域的发展进行了总结,并提出在该研究领域中引入电刺激等品质改良方法以提高热剔骨工艺肉品品质的建议。     

热剔骨工艺及改进方法研究进展

阐述了现代化热剔骨工艺的特点及热剔骨工艺中的肉品成熟嫩化过程,同时介绍了国际热剔骨工艺研究领域及肉类成熟领域的研究进展,对这一领域的发展进行了总结,并提出在该研究领域中引入电刺激等品质改良方法以提高热剔骨工艺肉品品质的建议。      

不同剔骨工艺对牛肉煎制食用品质的影响研究

为研究不同剔骨工艺对牛肉煎制食用品质的影响,以西门达尔牛的外脊为原料,测定冷剔骨(L)、热剔骨成熟(R)及热剔骨速冻(RS)工艺条件下的肉色泽,pH,失水率,蒸煮损失,剪切力,硬度,嫩度,质地剖面分析(TPA),感官评定。研究结果表明:RS组牛肉的剪切力值和硬度值较其他两组小,但持水力较差,并且煎制后的多汁性与另两种差异显著(p0.05),食用品质差;R组牛肉的黏着性与另外两种工艺差异显著(p0.05),与L组牛肉的剪切力值差异不显著(p0.05)。由此判断,L组和R组牛肉较RS组牛肉更适宜作为煎制牛排原料。     

国外肉品品质改良研究进展

研究肉品品质改良对于指导肉品生产、优化加工工艺、提高食品品质等具有重要意义。本文综述了近5年国外肉品品质改良的最新研究进展,主要分析了日粮调节、屠宰和成熟工艺、基因改良、热加工、食品添加剂使用和贮存工艺优化对肉品色泽、风味、组织状态等食用品质的影响,以期为国内相关研究提供参考和借鉴。     

电刺激和成熟对冷热剔骨牦牛肉品质的影响

为了研究电刺激和成熟对冷热剔骨牦牛肉品质的影响,将18头甘南公牦牛随机分为2组(电刺激组ES和非电刺激组NES),劈半后左、右半胴体分别进行热剔骨(HB)和冷剔骨(CB)处理,并对宰后成熟21 d内背最长肌的品质(pH、剪切力、压力失水率、蒸煮损失和肉色L~*、a~*和b~*)进行测定。结果显示:热剔骨使宰后9 h内牦牛肉温度降低快,导致冷收缩的发生;宰后1~14 d,热剔骨组牦牛肉剪切力值显著高于冷剔骨组(P0.05);宰后0~3 d,HB组的压力失水率显著高于CB组(P0.05)。电刺激显著加快牦牛肉pH的降低,防止冷收缩变硬;宰后1~14 d,ES组牦牛肉剪切力值显著低于NES组(P0.05)。宰后成熟使牦牛肉剪切力值和蒸煮损失降低(P0.01),肉色L~*、a~*和b~*显著增加(P0.01)。结论 :电刺激结合成熟显著提高了冷热剔骨牦牛肉嫩度,改善了牦牛肉品质,拓宽了牦牛肉在西餐、烧烤、涮食、爆炒等的食用途径,为我国牦牛肉增值提供理论和技术支撑。     

宰后成熟时间与温度对牦牛肉品质影响

牦牛肉热剔骨真空包装后分别于2、10℃成熟,在成熟1、2、3、4、6、12、18d分别测定pH、剪切力、蒸煮损失及肉色值,研究时间及温度对牦牛肉成熟过程中品质变化的影响。结果表明:1~12d贮藏过程中,2℃成熟的牦牛肉pH持续上升,10℃成熟的牦牛肉pH变化不明显,12~18d中两者pH均有不同程度降低;2、10℃成熟对牦牛肉嫩度均有明显改善作用,但是10℃成熟牦牛肉剪切力极显著低于2℃成熟;牦牛肉成熟过程中肉色L*、a*、b*、C*、h呈现整体上升趋势。总体认为热剔骨牦牛肉真空包装于2℃成熟18d可以基本完成成熟;而达到相同成熟品质,10℃成熟较2℃成熟需要时间更短。      

宰后成熟对生鲜肉品质影响的研究进展

作为一种肉品增值手段,成熟技术多年来在全球肉类工业中已被广泛应用。在宰后初期肌肉转化为可食用肉及后期成熟过程中所发生的一系列生化变化都会对肉的品质产生重要影响。因此,通过优化成熟方案并引入新型成熟技术来有效提升肉品品质（特别是嫩度）尤为重要。近年来,对肉品宰后生理生化机制的探索和新型成熟技术的研究始终是该领域的热点,然而目前鲜见对该方面最新进展的综合性报道。因此,本文系统地总结了对肉品质起决定性作用的宰后早期生理生化变化,概述了现行不同成熟方法（干法成熟和湿法成熟）对肉品质的影响,并对新型成熟技术的发展及其对品质的改善效果进行了综述,以期为满足消费者日益增长的高品质肉品消费需求和促进我国肉品加工行业的发展提供理论技术指导和发展思路。     

热休克蛋白对宰后成熟过程中肉品质影响的研究进展

宰后成熟对肉品质的影响是肉品科学领域的研究热点之一,宰后成熟过程中肉发生肌原纤维蛋白的降解,其影响机制还存在学术上的分歧。动物宰后造成的缺血、缺氧环境刺激了热休克蛋白的表达。该类蛋白质因具有分子伴侣、抗细胞凋亡、维持蛋白质结构稳定等作用,因此,热休克蛋白对宰后成熟过程中肉品质产生一定影响。目前,热休克蛋白尤其是小热休克蛋白对肉品质的影响国内外均已有报道,但结论并不一致。文中主要介绍了几种重要的热休克蛋白分子结构特征和功能,并进一步论述了热休克蛋白与宰后成熟过程中肉色、嫩度、保水性之间均存在一定的关系。      

热休克蛋白对宰后成熟过程中肉品质影响的研究进展

宰后成熟对肉品质的影响是肉品科学领域的研究热点之一,宰后成熟过程中肉发生肌原纤维蛋白的降解,其影响机制还存在学术上的分歧。动物宰后造成的缺血、缺氧环境刺激了热休克蛋白的表达。该类蛋白质因具有分子伴侣、抗细胞凋亡、维持蛋白质结构稳定等作用,因此,热休克蛋白对宰后成熟过程中肉品质产生一定影响。目前,热休克蛋白尤其是小热休克蛋白对肉品质的影响国内外均已有报道,但结论并不一致。文中主要介绍了几种重要的热休克蛋白分子结构特征和功能,并进一步论述了热休克蛋白与宰后成熟过程中肉色、嫩度、保水性之间均存在一定的关系。     

超低压电刺激和热剔骨工艺对牦牛肉品品质的影响

为了探究超低压电刺激技术对热剔骨牦牛西冷的改善效果,选择18头甘南牦牛随机分为3组,分别进行超低压电刺激(21 V,50 Hz,0.25 A,1 min&2 min)和未电刺激处理后,左半胴体进行热剔骨,右半胴体跟腱吊挂,于宰后45 min、24、48、72 h测定西冷的剪切力值、持水力、肉色。结果表明:超低压电刺激处理有效降低了宰后3 d牦牛西冷的剪切力值,同时抵消了热剔骨工艺对牦牛西冷剪切力值所造成的负面影响;超低压电刺激处理对牦牛西冷持水力无显著影响,未减弱热剔骨工艺所造成的牦牛西冷持水力下降;而超低压电刺激结合热剔骨有效改善了牦牛西冷的色度值,单独热剔骨工艺则对牦牛西冷肉色无显著影响。     

Hot boning of intact carcasses: a procedure to avoid central nervous system self-contamination in beef and beef products

Compared with traditional boning of split refrigerated carcasses, hot boning of intact carcasses (the removal of meat from the skeleton prerigor) provides several commercially important cuts, may improve quality and reduce refrigeration costs, and may reduce the contamination of carcasses with central nervous system (CNS) tissue. In a comparative study of hot boning of intact and split carcasses, the CNS tissue contamination of intact carcasses was negligible (as measured with the CNS-related proteins glial fibrillary acidic protein and S-100 protein), but split carcasses were highly contaminated. The same trends were observed for dissection worktables used during the boning process. Most current boning plants have processing lines that are organized for boning carcass quarters, where the carcasses, in addition to transversal division, also are split horizontally. This part of the boning process was incorporated in the design of our study. Nine of the 18 intact carcasses were split horizontally between thoracic vertebrae 10 and 11 before they were hot boned. CNS tissue contamination was not detected on the carcass site related to this procedure. The amount of CNS tissue contamination was similar in boned cuts and minced meat from split and intact carcasses, except in the forerib. Boning of split carcasses appears to reduce CNS tissue contamination significantly to a level comparable to that of intact hot-boned carcasses.     

Partial least squares (PLS) regression for the analysis of instrument measurements and sensory meat quality data

The partial least squares (PLS) regression technique was used to examine meat quality data derived from instruments (including Warner-Bratzler shear force and Instron Compression) and sensory panels. The data related to beef longissimus dorsi muscles collected during trials to study the effect of hot boning on meat quality. The univariate analysis of tenderness showed that over 60% of the variation in sensory tenderness, and almost 60% of the variation in sensory acceptability, could be explained from instrument variables and a consideration of boning and ageing time. Graphical displays from the analysis indicated that hot boning (either at 1 or 4 h) had little effect on meat quality. Graphical displays demonstrated a possible important effect of vacuum-pack ageing on acceptability. For this data set, it appears that samples of approximately equivalent tenderness differ in acceptability, depending on whether the samples have been aged for 1 or 4 weeks. This finding may have practical importance in attempts to predict eating quality (acceptability) from instrument measurements. Separate equations are necessary for products aged for different periods. ?     

The effect of electrical stimulation, time of boning and high temperature conditioning on sensory quality traits of porcine Longissimus dorsi muscle

The effects of electrical stimulation (300 V, 1 A, 50 Hz, AC, 30 s) and high temperature conditioning (4h/15°C) on sensory quality traits of hot- and cold-boned, vacuum-packaged longissimus dorsi muscle of halothanenegative pigs were assessed at 12 days post mortem. Electrical stimulation accelerated the pH fall significantly, but had negligible effects on all quality traits measured, i.e. shear force, drip formation, fresh meat colour, cooking loss and degree of sarcoplasmic protein denaturation (p > 0·05). As compared with cold boning, hot boning significantly lowered drip losses (p < 0·05). Shear forces, which increased as a result of hot boning (p < 0·05), were reduced again through a 4 h/15°C conditioning period before chilling at 1 ±1°C. In addition, high temperature conditioning resulted in significantly lower drip losses (p < 0·05). It is suggested that prevention of cold-induced reduction of proteolytic enzyme activity is primarily responsible for both these findings.     

Functional Properties of Pre-rigor Pork: Hot vs Cold Processing of Cooked Shoulders and Hams

In two experiments, the effects of processing shoulders and hams, pre-rigor and post-rigor, with and without polyphosphates, were compared. Pre-rigor processing included hot boning of shoulder or ham muscles at approximately 30 min post mortem followed by injection of a deep-chilled brine (?6°C) within the next 60 min. Except for the brine temperature, the processing procedures were similar for hot and cold processing. Both in shoulder and ham muscles hot and cold processing resulted in a product similar in cooking yield and sensory quality. The present study failed to substantiate that the superior water binding potential of pre-rigor meat could compensate for the higher cooking loss when using phosphate-free brines.     

The effect of boning and plant cleaning on the contamination of beef cuts in a commercial boning hall

A series of experiments was carried out to determine the effect of boning and trimming on the bacteriology of a number of beef cuts. At the same time the plant cleaning programme was investigated to determine its efficiency in reducing bacterial numbers on different surfaces within the boning hall. The hygiene of the personnel involved in boning was also studied. The work showed that the level of contamination varied with the different cuts of meat. On the striploin and fillet the level of contamination was higher than on the inside or outside rounds. This variation resulted mainly from the amount of handling the meat received. The cleaning programme in the plant was shown to be very inefficient in reducing bacterial contamination. Personnel hygiene was also considered inadequate. It is probable that both surfaces and personnel were sources of contamination of the meat.     

Tenderness, ageing rate and meat quality of pork M. longissimus thoracis et lumborum after accelerated boning

The impact of accelerated boning on tenderness, ageing rate and meat quality of pork longissimus muscle was investigated. Accelerated boning of eight Large White×Landrace pork carcasses at 30 min post-mortem followed by chilling at 0°C resulted in tougher pork with higher drip loss and a darker surface lightness relative to conventional boning at 24 h post-mortem. The increased toughness was still observed at 4 days post-mortem, a time by which 80% of ageing generally had occurred as seen in experiment 2. The increased toughness could be attributed to cold shortening and a reduction in proteolysis.     

Carcass composition and yield of Alaskan reindeer (Rangifer tarandus tarandus) steers and effects of electrical stimulation applied during field slaughter on meat quality

Twenty six adult reindeer steers (>3 years old) were used in a study to evaluate the effect of electrical stimulation (ES) on the quality of hot-boned, rapidly frozen shoulder meat and of the striploin (M. longissimus, LD) from carcasses held at +3°C for 48h. Carcass yield and composition was determined from the left carcass half from which the shoulder meat was not removed. The shoulder meat was processed frozen into cubed, sliced or ground products. Proximate composition of the LD, meat color and water-holding capacity were very similar for the ES (n=15) and non-electrical stimulation (NES; n=11) groups. Ultimate pH and shear force values were significantly lower in the ES meat (LD), however a trained sensory panel could not detect differences between the two groups in any of the measured sensory attributes. Consumer preference tests demonstrated that ES increased tenderness in the cubed and sliced products made from field slaughtered reindeer shoulder meat. ES in combination with hot boning and processing of boneless frozen meat can be used in field slaughter systems for reindeer to improve meat quality and to increase the potential value of the carcass.     

Colour stability of bovine Longissimus and Psoas major muscle as affected by electrical stimulation and hot boning

From eight electrically stimulated and eight non-stimulated cows the righthand-side longissimus and psoas major muscles were hot boned within 1 1 2 h post mortem, vacuum packaged and chilled and storred at 1±1°C. Immediately after slaughter, the lefthand carcass-sides were blast-chilled for 1 1 2 h and subsequently chilled at 1±1°C until the following day. After cold boning, the longissimus and psoas major muscle were packaged, chilled and stored as the hot boned muscles. After 12 days of storage, steaks, cut from the primals, were displayed at 1±1°C under continuous illumination (300-400 lx). Colour measurements after 0, 2 and 4 days of display revealed a significant (p<0·10) effect of time of boning on non-stimulated psoas major muscle (lower values for a (?), b (?) values, chroma and %R630-%R580). Significant effects of electrical stimulation were not observed. Changes in hue tended to be more pronounced when the meat had been stimulated. Changes in chroma were largest (p<0·10) is non-stimulated, hot boned psoas muscle. Analysis of variances showed that in the longissimus muscle significant effects (p<0·10) of time boning and electrical stimulation were present. The effect of time of boning was often influenced by the use of electrical stimulation. Changes in hue and chroma indicated that hot boned samples had a higher colour stability than cold boned controls, especially when the carcasses had not been stimulated electrically. The observed differences in colour stability were rather small in all treatment groups and are not expected to present any practical merchandising problem.     

Eating quality of commercially processed hot boned sheep meat

The aim of this work was to establish consumer perceptions of the eating quality of commercially processed hot boned sheep meat. The eating quality scores for tenderness, flavour, juiciness, and overall liking of grilled m. longissimus thoracis et lumborum (LL) were derived from untrained consumers. The animals used in this experiment were sourced from three different properties and were of various ages, breed, and sex, and had been on various quality pastures. All carcases were subjected to immobilisation, spinal discharge and high voltage electrical stimulation and boned within 2 h of slaughter. All LL samples were frozen after boning according to the system applied at the abattoir and samples kept for consumer assessment and measurement of meat quality. The results showed, on average carcases entered rigor at high temperatures with a pH of 5.95 at 29.3 °C. With an average sarcomere length of 1.68 μm, some shortening was evident and there was a significant difference between lots in sarcomere length (P < 0.05). A large percentage (82%) of samples had a pH greater than 5.8 at the time of freezing. All samples taken for shear force analysis exceeded a recommended threshold for acceptable table meat of 49 N and there was no significant difference between lots (P > 0.05). Only 13.5% of the samples met the ‘good everyday’ requirement following sensory assessment and there were significant differences between lots for eating quality traits (P < 0.05). This work clearly shows that the application of effective electrical stimulation is not sufficient to ensure that hot boned sheep meat will be suitable as a table meat. These findings highlight the need for the inclusion of other intervention techniques.