碳酸钠对牛肉嫩化效果及品质的影响

为探讨我国传统烹饪中食碱对牛肉的嫩化效果,研究了不同浓度(0、0. 25、0. 30、0. 35、0. 40 mol/L)Na_2CO_3对西门塔尔杂交牛肉的嫩化效果,并探究了Na_2CO_3注射对牛肉肌纤维及结缔组织的影响。结果显示,牛肉的pH、肌原纤维小片化指数随着Na_2CO_3浓度的增大而增大,剪切力、蒸煮损失、胶原蛋白含量随之减小;当浓度超过0. 35 mol/L后,牛肉的色泽和感观评价都变差。研究证明Na_2CO_3能有效改善牛肉嫩度,当浓度为0. 35 mol/L时效果最好,且Na_2CO_3注射能有效提高牛肉肌肉保水性,增大肌纤维直径及间隙,破坏肌纤维结构,使肌纤维小片化指数增加,降低结缔组织胶原蛋白含量。该研究为新型牛肉嫩化技术的研究提供了理论依据。     

磷酸盐对牛肉嫩化作用的研究

研究了酸性焦磷酸盐(SAPP)、焦磷酸盐(TSPP)、三聚磷酸盐(STPP)对牛肉半腱肌的嫩化作用。结果表明,分别用3%的磷酸盐溶液浸渍处理后,TSPP和STPP极显著地改善了牛半腱肌的嫩度(P<0.01),SAPP显著改善了牛半腱肌的嫩度(P<0.05)。另外,本试验对肉的蒸煮损失和胶原蛋白的溶解度进行了测定。     

新型牛肉嫩化技术研究进展

嫩度是评价牛肉品质的关键指标,直接影响消费者的购买意向。因此,如何改善牛肉的嫩度一直是肉品研究领域的重点。随着科学技术的发展,新型肉类嫩化技术不断涌现,目前在牛肉生产中新引入的智能拉伸、超声波和脉冲电场等技术在牛肉生产领域得到广泛关注。基于近期的研究成果,该文详细深入地对上述3种技术的作用机制、嫩化效果及应用前景进行了综述,发现高强度(10~1 000 W/cm^2)低频率(20~100 k Hz)超声波在改善牛肉嫩度方面效果显著,是一种有效的牛肉嫩化技术,多种肉类嫩化技术的复合应用也是未来肉类产业发展的趋势。     

生姜汁嫩化牛肉方法的研究

以生姜为原料,研究利用生姜中生姜蛋白酶对牛肉的嫩化效果。利用单因素实验及正交试验,确定了牛肉嫩化所需的生姜汁浓度,缓冲液的pH值,处理温度及处理时间。结果表明:生姜汁对牛肉的嫩化效果良好,生姜汁的最佳浓度为5%,缓冲液的最佳pH值为8.0,最佳处理温度为40℃,处理时间为60min。     

生姜蛋白酶嫩化牛肉效果的研究

研究了生姜蛋白酶对牛肉的嫩化效果,对酶用量、pH、处理温度、处理时间进行了测试,并且进一步通过L9(34)正交实验选择出最佳嫩化工艺.结果表明:生姜蛋白酶对牛肉的嫩化效果十分显著,通过正交实验确定的生姜蛋白酶对牛肉嫩化的最佳工艺条件是:酶用量为0.06%,pH为7.0,处理温度为50℃,处理时间为2h.     

NaCl对热诱导牛肉肌原纤维蛋白氧化及消化率的影响

摘 要: 目的 分析不同盐浓度下肌原纤维蛋白氧化和消化率的变化规律。方法 以加热后的牛肉肌原纤维蛋白为研究对象, 探究不同NaCl浓度(0、0.2、0.4、0.6、0.8 mol/L)对其氧化程度的影响, 并采用体外模拟消化试验, 分析不同NaCl浓度对热诱导牛肉肌原纤维蛋白(85℃水浴)消化率的影响。结果 NaCl会造成肌原纤维蛋白氧化且可显著提高肌原纤维蛋白消化率。当NaCl浓度从0逐渐增加到0.8 mol/L时, 肌原纤维蛋白消化率表现为先升高后降低的趋势, 当浓度达到0.4 mol/L时其消化率达到最高的79.78%, 较0 mol/L的55.37%提高了0.45倍。羰基、活性巯基、多肽释放量和游离氨基酸的含量也保持相同趋势, 在NaCl浓度达到0.4 mol/L时, 羰基含量高达7.95 nmol/mg prot,活性巯基含量高达0.42mmol/g,多肽含量达到最高3.475 mg/mL, 游离氨基酸含量达到4740.23 μg/mL。结论 NaCl会造成蛋白质氧化, 适度的NaCl可以促进热诱导牛肉肌原纤维蛋白的消化吸收, NaCl浓度为0.4 mol/L时消化率达到最高。该结果对研究低钠肉制品具有一定指导意义。     

Effects of elastase from a Bacillus strain on the tenderization of beef meat

The tenderization effect of a new elastase from Bacillus sp. EL31410 was investigated on beef meat. Meat tenderization was done by dipping the meat cut in a solution containing proteolytic enzymes after freeze-dehydration. It was found that a marination time of 4 h was enough for enzyme adsorption. The samples were treated for 4 h in different enzyme solutions and then was stored at 4 °C for 24, 48, 72 h, and subjected to texture measurement, sensory evaluations, biochemical analysis and histological observations. A marked decrease in hardness, by texture measurements, was observed in the meats with papain and elastase and higher sensory scores for tenderness were observed in the meats treated with enzymes than in the control. The papain-treated beef meat received the highest score for tenderness, but the scores given for juiciness and taste were lower than that of the control. Rapid increases of fragmentation of myofibrils from the enzyme-treated meat were observed in the first 24 h of storage, especially for papain-treated meat. Meantime, elastin of myofibrilar structure was selectively degraded by elastase compared with the control when stored at 4 °C for 48 h as shown by electron microscopy. These findings suggest that Bacillus elastase (EL31410) is a promising substitute for papain as a favourable meat tenderizer.     

牛肉高压嫩化工艺参数的研究

通过对牛肉施加不同的压力和不同时间的处理,分析测定牛肉在宰后理化指标的变化,研究了高压处理对牛肉感官品质的影响。结果表明在室温下用250MPa的压力处理宰后热剔骨（6h以内）真空包装的牛肉10min,0－4℃冷藏条件下贮存2－3d,可获得理想嫩度的牛肉,处理可缩短牛肉的宰后成熟时间,并可延长保质期。     

Effects of double-muscling on carcass quality, beef tenderness and myofibrillar protein degradation in Belgian Blue White bulls

Carcass properties and meat quality characteristics of 32 Belgian Blue White double-muscled bulls (DM) were compared with those of 59 bulls of the same breed with normal conformation (N). DM showed superior carcass quality as revealed in increased dressing percentage, meat production yield, conformation grade, muscle/fat and muscle/bone ratios (all P < 0·001). Longissimus dorsi (LD) shear force values, drip and cooking losses at 8 days post mortem (pm) were significantly higher (P < 0·001) for DM, whereas sarcomere lengths were not different. Calpain 1 and calpastatin levels at 1 h and 24 h pm were tremendously decreased in DM as were also cathepsin B and L levels at 1 and 8 days pm (P < 0·001). As evident from semi-quantitative SDS-PAGE, these differences were accompanied by higher titin and lower 30 kDa levels (P < 0·001) in DM. Troponin-t levels were not different, but very low. Intramuscular collagen content was significantly lower in DM (P < 0·001). This suggests that lower background toughness in DM was compensated for by reduced post-mortem proteolytic tenderization. Discrepancy with literature reports regarding tenderness of DM might be related to the extreme muscularity of the Belgian Blue White breed, compared to other DM breeds. The results also suggest that reduced protein turnover might be involved in the muscle hypertrophy phenomenon within this breed, because of likely reduced levels of calpains and cathepsins in living DM animals.     

罗非鱼肌纤维蛋白糖基化工艺优化

目的:改善罗非鱼肌纤维蛋白的乳化特性和溶解度,开发新型乳化剂和功能食品。方法:利用低聚半乳糖(GOS)修饰罗非鱼肌纤维蛋白(TMP),探究不同TMP/GOS质量浓度、pH值、温度、时间等工艺条件对TMP-GOS缀合物接枝度、溶解度、乳化活性和乳化稳定性的影响;以乳化稳定性为响应值,对TMP-GOS缀合物制备工艺进行响应面优化;通过内源性荧光光谱、表面疏水性、傅里叶红外光谱和peakering乳液显微观察,分析验证TMP-GOS缀合物功能特性。结果:TMP/GOS(m_TMP∶m_GOS=1∶1)质量浓度27.34 mg/mL、pH 11.2、反应温度79.9℃、反应时间4.09 h。该工艺下,糖基化罗非鱼肌纤维蛋白的乳化稳定性为(90.30±1.44) min、乳化活性为(4.70±0.03) m²/g、溶解度为(66.09±0.52)%。较改性前分别提升了112.97%,62.07%,129.39%。罗非鱼肌纤维蛋白糖基化接枝度为34.17%,蛋白水解程度大,蛋白结构展开,表面疏水性指数下降55.68%。结论:低聚半乳糖对...     

生鲜牛肉嫩度的影响因素和嫩化技术

主要论述了生鲜牛肉嫩度的影响因素,诸如性别和年龄、肌内脂肪和胶原蛋白含量等,同时嫩化技术得到了重点阐述、包括了排酸成熟、机械法、电刺激等。希望为冷鲜牛肉的生产、品质的改善提供理论依据和技术支持。     

Effects of microwave and water bath heating on the interactions between myofibrillar protein from beef and ketone flavour compounds

This paper presents the effects of microwave on the structure changes of myofibrillar protein compared with traditional water bath heating method. Under microwave or water bath heating conditions, α-helix conformation of myofibrillar protein was converted into β-turn, β-sheet and randomly coiled structures gradually. T he fluorescence intensity of myofibrillar protein exhibited a marked red shift of the maximum absorption wavelength after microwave or water bath treatment. Total sulfhydryls groups and surface hydrophobicity contents were increased with progressing microwave or water bath treatment time. Results indicated that the thermal effects of microwave dominated the structure changes of myofibrillar protein, and microwaving also had an apparent influence on myofibrillar protein structure compared with water bath heating due to its nonthermal effects, and thus affecting the retention and release of ketone flavour compounds.     

低盐嫩化牛干巴与传统牛干巴的品质比较

对采用中心组合设计优化的最佳实验组与传统牛干巴的品质进行比较,结果显示:最佳实验组肌原纤维小片化指数(MFI)、综合感官品分值高于传统组,剪切力、Na+浓度低于传统组(p<0.05)。筛选的低盐和嫰化技术对降低传统牛干巴的盐含量,提高肉的嫩度是有效的。     

The characteristics of selected physico-chemical properties of chemically modified myofibrillar protein

The objective of the present research was to investigate the influence of chemical modification and method of preservation of separated myofibrillar proteins on their physico-chemical properties. Myofibrillar proteins were the subject to succinylation or acylation and after modification one part of each preparation was lyophilised, the second part was spray dried and the third part was frozen. The chemical composition of protein preparations did not change significantly after any method of treatment. The process of chemical modification influenced the water-holding capacity and protein digestibility in vitro. Modified samples absorbed less water than standards and also were less susceptible to enzymatic hydrolysis. The shape of sorption isotherms of modified proteins was typical for hygroscopic products and hysteresis loops were observed.     

冷鲜牛肉嫩度的影响因素和嫩化技术

主要论述了冷鲜牛肉嫩度的影响因素,诸如性别和年龄、肌内脂肪和胶原蛋白含量等,同时嫩化技术得到了重点阐述,其包括了排酸成熟、机械法、电刺激等。希望为冷鲜牛肉的生产、品质的改善提供理论依据和技术支持。     

Quantification of beef myofibrillar proteins by SDS-PAGE

A semi-quantitative determination of beef myofibrillar proteins using sodium, dodecyl sulphate polyacrylamide gel electrophoresis is described. Bovine serum albumin was used as internal standard. Results indicate a linear relationship between densitometric readings after staining with Coomassie brilliant blue R(250) and protein content. Recoveries of four pure proteins, loaded within a range of 0·5-4 μg, were between 92 and 110%. Heating of beef myofibrillar protein samples during dissolution is shown to be unnecessary. The method allows the quantitative study of myofibrillar degradation during beef aging, without overlapping of troponin-T with tropomyosin bands.     

自由基氧化对中国对虾肌原纤维蛋白的影响

本实验研究经自由基氧化体系处理过的中国对虾肌原纤维蛋白,由于蛋白质氧化而引起的中国对虾肌原纤维蛋白结构以及性质的变化,包括羰基含量,二聚酪氨酸含量、巯基含量以及肌原纤维蛋白表面疏水性,并通过SDSPAGE来观察蛋白质氧化后的降解情况。其中,模拟氧化采用自由基氧化体系（包含FeCl₃和抗坏血酸浓度为0.1 mmol/L,过氧化氢浓度为0、1、5、10 mmol/L）分别氧化1、3和5 h。实验结果显示,经自由基氧化体系氧化后的中国对虾肌原纤维蛋白的羰基含量、二聚酪氨酸含量和表面的疏水性随着氧化剂浓度的增加以及氧化时间的增长而显著升高（p<0.05）,并且自由巯基含量显著下降（p<0.05）。由SDS-PAGE凝胶可以看出,不同氧化剂浓度处理后的蛋白质降解情况也有显著差异。由此可以得出,自由基氧化可以影响中国对虾肌原纤维蛋白的羰基含量、二聚酪氨酸含量、巯基含量、肌原纤维蛋白表面疏水性以及蛋白质的降解程度。      

冷冻及解冻处理对肌原纤维蛋白理化性质的影响

研究不同的冻结温度（-18 ℃和-50 ℃）和解冻方式（微波解冻、空气解冻及4 ℃解冻）对猪肉肌原纤维蛋白含量和理化特性的影响。结果表明,在不同冻结温度与解冻方式下,肌原纤维蛋白的含量、溶解性、乳化活性、乳化稳定性、起泡性及起泡稳定性均降低,表面疏水性增加。其中,采用-18 ℃冻结,微波解冻处理的肌原纤维蛋白与对照组相比,其溶解性、乳化性、乳化稳定性、起泡性及起泡稳定性分别降低了38.7%、16.5%、28.3%、39.6%和17.3%;采用-50 ℃冻结,4 ℃解冻的蛋白其含量（6.32%）、溶解性（22.05%）、乳化性（7.89 m2/g）、乳化稳定性（32%）、起泡性（30.95%）及起泡稳定性（62.25%）与其他处理对应的各指标相比,理化特性均保持较好。不同的冷冻和解冻条件下,肌原纤维蛋白各指标之间的变化相互关联。     

Effects of Agaricus bisporus on gel properties of chicken myofibrillar protein

The gel-forming ability of myofibrillar protein (MP) is highly correlated with the characteristics of emulsified meat products. Incorporation of Agaricus bisporus (Ab) powder into MP gels may enhance its gel properties to facilitate the development of a novel and safe meat product. Therefore, this study investigated the effects of Ab powder on gel strength, water holding capacity (WHC), texture, rheological behaviour, LF-NMR spin–spin relaxation (T₂), microstructure and protein secondary structure of the MP gel system. The results indicated that the gel strength, WHC, G' value and G" value were significantly improved when the addition of Ab powder increased from 0% to 6% (P < 0.05). Meanwhile, the T₂ relaxation time was shortened, and free water was transformed into immobilised water. The texture of the gel was improved when 1%–4% Ab powder was added compared to the control. Furthermore, Ab filled in the gel network and promoted the unfolding of MP α-helix and the formation of MP β-sheet during the thermal denaturation of MP, leading to a dense aggregated network structure. The study suggested that Ab could be a promising ingredient in improving chicken MP's gel properties and developing fat-reduced meat products.     

The effects of transglutaminase on the functional properties of the myofibrillar protein concentrate obtained from beef heart

The aim of the present study was to evaluate the effect of bacterial transglutaminase on the functional properties of the myofibrillar protein concentrate from beef heart. The degrees of hydration and aggregation and emulsifying properties were studied. The degree of polymerization of the myofibrillar proteins depended on the enzyme concentration and setting time; the best results in terms of functional properties were obtained with 0.3 g transglutaminase/100 g protein with 60 min setting at 35 °C. This investigation confirms that transglutaminase may be used for the production of myofibrillar protein aggregates with enhanced functional properties.