羊肉嫩化技术及其机理的研究进展

综述了近年来羊肉加工中的嫩化技术及其机理的研究现状,详细分析了羊肉的酶解嫩化法、CaCl2液注射嫩化法、超高压嫩化法、超声波嫩化法和电刺激嫩化法的研究现状及其嫩化机理,提出了羊肉嫩化研究应用中存在的问题和研究发展方向,对羊肉生产加工具有一定的指导作用。     

碳酸氢钠联合超声波对羊肉嫩度及其肌动球蛋白含量的影响

探究NaHCO_3与超声波联合处理对羊肉嫩化效果的影响。通过比较未处理组(C组)、去离子水处理组(W组)、NaHCO_3处理组(S组)及其相应的联合超声波处理组(W+U,S+U)的p H、蒸煮损失、质构、剪切力、持水力、肉品组织切片和表面微观结构以及肌动球蛋白解离程度等指标,阐明了Na HCO3联合超声波处理对羊肉嫩度及肌动球蛋白含量的影响。结果表明,与未处理组相比,经去离子水联合超声波处理(W+U)和NaHCO_3联合超声波处理(S+U)的各项指标均得到良好改善。S+U处理组的羊肉p H最大、质构参数较优,肌原纤维断裂明显、蛋白结构疏松,促进了羊肉肌动球蛋白的解离; S+U处理组蒸煮损失最低、具有良好的保水效果,剪切力值显著降低。NaHCO_3联合超声波对羊肉嫩化效果明显,为进一步改善肉品品质提供科学依据。     

滚揉法、氯化钙法与木瓜蛋白酶对羊肉嫩化效果的比较研究

优选出滚揉法、氯化钙法和木瓜蛋白酶对羊肉嫩化的最适条件,研究了3种嫩化方法对羊肉的嫩化效果.研究结果表明:滚揉嫩化的最适条件为:滚揉60min,滚揉后在10℃的条件下放置8h;氯化钙嫩化的最佳条件为:在羊肉中注射2%的CaCl2 溶液(400m mol),滚揉30min后,在10℃条件下放置8h;木瓜蛋白酶的最佳嫩化条件为:在羊肉中注射木瓜蛋白酶,滚揉30min,然后在10℃的条件下放置8h.羊肉中添加0.005%的木瓜蛋白酶的嫩化效果优于其它两种,其次是氯化钙法.     

超声波处理对淘汰蛋鸡嫩化效果的初步研究

采用超声波对淘汰蛋鸡肉的嫩化效果进行了初步的研究，对超声波的频率，功率，处理时间及处理媒质CaCl2的不同浓度进行了测试对比，结果表明：超声波与CaCl2相结合对淘汰蛋鸡肉的嫩化效果明显，超声渡的最佳频率为26．4kHz，功率为400W，处理时间15min，处理媒质CaCl2浓度为250mmol／L。     

超声波嫩化处理对淘汰蛋鸭中钙激酶活性影响的研究

采用不同功率及不同处理时间研究了超声波嫩化淘汰蛋鸭胸肉的效果。结果表明:超声波处理可以提高钙激活酶的活性,通过钙激活酶对肌原纤维蛋白质的水解作用降低肌肉的剪切力。超声波功率及超声波处理时间是决定嫩化效果的两个重要因素。淘汰蛋鸭胸肉最适的超声波嫩化条件分别为300W功率、15min处理时间。相关分析证实钙激活酶活性与肌肉剪切力之间呈现负相关(R20.76)。     

不同处理对新疆羊半腱肌嫩度的影响

目的:寻求一种成本低、安全健康、嫩化效果好的嫩化方法。方法:以剪切力、pH值、蒸煮损失、肌原纤维小片化指数(myofibrillar fraglllentation index,MFI)、胶原蛋白含量及其溶解度、羊半腱肌全骨架蛋白降解情况等为评价指标,研究腌制结合滚揉、真空滚揉及腌制结合真空滚揉对羊肉嫩度的影响。结果表明:3种处理对羊肉的剪切力、pH值、蒸煮损失、肌原纤维小片化指数均影响显著。结论:采用真空滚揉对羊肉嫩化效果最佳。     

超声波对羊肉嫩化效果的研究

本试验以山羊肉为材料进行了超声波处理,在前人的基础上选择不同时间的超声处理,分别处理0min,1min,3min,5min,7min,10min,15min,处理后在0～4℃成熟0d,1d,2d,3d,4d,5d,7d.对羊肉的可溶性蛋白浓度(concentration of soluble protein,CSP)、肌小节片断化指数(myrifribril fragment index,MFI)分别作了定性和定量试验,二者的相关系数为0.75,提出了用CSP作为评价羊肉嫩度的指标,比MFI测定简单方便.实验结果表明超声波处理明显提高了羊肉的嫩度.     

包装方式和宰后不同时间包装对羊肉品质的影响

为探究包装方式和宰后不同时间包装对羊肉贮藏品质的影响,本研究对宰后1 h热分割羊肉和冷却成熟24 h后的分割羊肉分别进行热收缩包装、真空包装、贴体包装、50%（体积分数,下同）O2＋50% CO2气调包装,测定其在（2±2）℃贮藏过程中pH值、色泽、贮藏损失率、蒸煮损失率、离心损失率、剪切力、挥发性气味的变化。结果表明：与宰后24 h包装相比,宰后1 h包装羊肉pH值在贮藏14 d时更高,但其贮藏期间色泽较好,色泽稳定性更高,贮藏损失率更低。从整体来看,3 种真空处理（热收缩包装、真空包装、贴体包装）羊肉嫩度均优于气调包装羊肉,且宰后1 h包装时真空条件处理对羊肉嫩化效果最好,宰后24 h羊肉在贮藏前期气调包装对羊肉嫩化效果较好;而无论何时包装,热收缩包装和气调包装羊肉贮藏损失率均显著小于其他处理组（P＜0.05）,在贮藏前期色泽及稳定性较好,但贮藏后期色泽稳定性下降明显,气调包装羊肉在14 d时已部分发绿,贮藏21 d时挥发性气味变化显著。综上,宰后1 h包装有利于提高羊肉贮藏期间色泽及持水力,改善真空处理羊肉嫩度,宰后24 h包装可提高50% O2＋50% CO2气调包装羊肉贮藏前期的嫩度;其中热收缩包装和气调包装羊肉持水力高,贮藏前期色泽及稳定性好,真空包装、贴体包装羊肉品质变化相对稳定,适宜长期贮藏。     

木瓜蛋白酶处理对羊肉干嫩度的影响

为了改善羊肉干的口感,主要研究了在羊肉干的加工制作过程中,用木瓜蛋白酶对羊肉进行嫩化处理,以酶的用量、pH、处理温度、处理时间等因素对羊肉干嫩度的影响进行试验。正交试验表明,木瓜蛋白酶最佳嫩化条件为酶用量40U/g、pH 8.0、处理温度25℃、处理时间60min。因素的显著性次序为:处理温度木瓜蛋白酶用量pH值处理时间。     

超声波与氯化钙对鸭肉嫩化的协同作用

以肌原纤维小片化指数和剪切力为考察指标,利用超声波与钙离子协同对淘汰蛋鸭肌肉进行嫩化研究,确定超声波与钙离子协同嫩化淘汰蛋鸭肌肉的最佳工艺条件,并分析肌原纤维小化片指数和剪切力之间的关系。结果表明:超声波与钙离子协同嫩化鸭肉的最适条件为超声波功率300 W、钙离子浓度200mmol/L、超声波处理时间15min、超声波处理温度40℃。超声波/钙离子协同嫩化鸭肉的肌原纤维小片化指数与剪切力之间存在着显著的相关性。     

超高压纯水射流切割羊胴体试验

目的:减少机械切割羊肉损耗。方法:采用龙门式超高压纯水射流切割平台，针对羊胴体的不同部位，选取不同的参数进行试验。对比切割效果、找出合适的切割参数并分析切割损耗。结果:针对常温羊肉、冷冻羊肉、羊排、羊脊柱、羊腿、羊颈部、剔骨取肉等几个方面进行了试验，明确了羊酮体不同部位、不同试验参数对切割效果的影响。结论:纯水射流切割对冷冻羊酮体的不同部位适应性不同，但均可以获得良好的效果而且损耗很小，对常温羊肉、羊腿、羊颈部等部位的切割效果不佳。     

羔羊皱胃酶提取技术的研究

以2周龄羔羊皱胃酶为原料,研究了食盐浓度、酒精浓度、pH以及提取液与皱胃粉比例(v/w)对羔羊皱胃酶提取效果的影响。结果表明,酒精浓度对提取效果无明显影响;当提取液中食盐浓度为5%、pH为4、提取液与皱胃粉比例为20∶1时,提取羔羊皱胃酶凝乳活性最高。     

介质阻挡放电低温等离子体处理对宰后羊肉品质的影响

利用不同时间（0、30、60、90、120 s）介质阻挡放电（dielectric barrier discharge,DBD）低温等离子体系统处理宰后羊双侧背最长肌,分析4 ℃贮藏期间样品pH值、色泽、汁液损失、剪切力、菌落总数和蛋白氧化等指标的变化,探究DBD低温等离子体处理对宰后贮藏过程中羊肉品质的影响。结果表明：在贮藏过程中,不同时间DBD低温等离子体处理后样品的pH值均比未处理样品低;随处理时间延长,亮度和黄度呈先上升后下降趋势;DBD低温等离子体处理对羊肉色泽和剪切力没有显著影响,但会加速羊肉中蛋白的氧化。DBD低温等离子体处理组能总体上显著降低贮藏期间羊肉中的细菌总数（P＜0.05）,贮藏5 d后对照组菌落总数为6.10（lg（CFU/g））,远超出限定值;而DBD低温等离子体处理组菌落总数在贮藏7 d后超过限定值,表明DBD低温等离子体处理可延长羊肉的贮藏保质期。综合考虑,DBD低温等离子体处理60 s对宰后贮藏过程中羊肉品质的负面影响最小。     

CRANBEFCRY JUICE MARINADE IMPROVES SENSORY AND MICROBIOLOGICAL PROPERTIES OF VACUUM-PACKAGED LAMB CHOPS

Marination was investigated as a means to add value and improve the palatability of lamb chops. Vacuum-packaged whole lamb loins (n = 24) were assigned randomly to a 14 or 20-day aging period. Loins were split and right and left sides were designated to receive one of two treatments: control or marinade with spice rub. Loins were cut into chops and chops were vacuum-packaged and displayed for 0–, 7– or 14-days in a retail display case. Chops from both aging periods assigned to the 0 day retail display period were evaluated for both raw and cooked characteristics by consumers. Consumers indicated that cooked appearance. odor, juiciness, flavor, tenderness, and overall-like were higher for treated chops than for controls (P < 0.05). However, consumers preferred the appearance of raw control chops over the appearance of raw treated chops (P < 0.05). Treated lamb chops had lower aerobic plate counts at 7 and 14 days of retail display for both aging periods (P < 0.05), and lower 2-thiobarbituric acid (TBARS) values than control chops (P < 0.05). A treatment × retail display day interaction (P < 0.05) was observed for TBARS values as treated chops had lower TBARS values than control chops as days of retail display increased. Marinating lamb chops improved palatability traits of cooked lamb chops and extended the shelf-life characteristics of raw lamb chops.     

Acceleration of Tenderization/Inhibition of Warmed-Over Flavor by Calcium Chloride-Antioxidant Infusion into Lamb Carcasses

Infusion of 0.3M calcium chloride plus 1% sodium ascorbate or 0.25% maltol into freshly slaughtered lambs resulted in acceleration of postmortem tenderization through activation of calcium dependent proteases, inhibition of lipid oxidation and retardation of warmed-over flavor on ground cooked patties from their meat. After storage 2 days at 4°C, patties from lamb carcasses treated with antioxidants retained more desirable flavor characteristics (meaty and musty/herby) of lamb, and had less off-flavor (painty and cardboardy) intensities.     

Shelf life extension of lamb meat using thyme or oregano essential oils and modified atmosphere packaging

The effect of thyme (TEO) and oregano (OEO) essential oils as well as modified atmosphere packaging (MAP) in extending the shelf life of fresh lamb meat stored at 4 °C was investigated. In a preliminary experiment TEO and OEO were used at concentrations 0.1 and 0.3% v/w while MAP tested included MAP1 (60% CO(2)/40% N(2)) and MAP2 (80% CO(2)/20% N(2)). Microbiological, physicochemical and sensory properties of lamb meat were monitored over a 20 day period. Sensory analysis showed that at the higher concentration both essential oils gave a strong objectionable odour and taste and were not further used. Of the two essential oils TEO was more effective as was MAP2 over MAP1 for lamb meat preservation. In a second experiment the combined effect of TEO (0.1%) and MAP2 (80/20) on shelf life extension of lamb meat was evaluated over a 25 day storage period. Microbial populations were reduced up to 2.8 log cfu/g on day 9 of storage with the most pronounced effect being achieved by the combination MAP2 plus TEO (0.1%). TBA values varied for all treatments and remained lower than 4 mg MDA/kg throughout storage. pH values varied between 6.4 and 6.0 during storage. Color parameters (L and b) increased with storage time while parameter (a) remained unaffected. Based primarily on sensory analysis (odour) but also on microbiological data, shelf life of lamb meat was 7 days for air packaged samples, 9-10 days for samples containing 0.1% of TEO and 21-22 days for MAP packaged samples containing 0.1% TEO.     

超声处理对黑豆蛋白与可溶性多糖复合物功能性质及结构的影响

将可溶性多糖与黑豆蛋白进行复合可以改变蛋白的许多功能性质。采用荧光分析、圆二光谱检测超声处理对黑豆蛋白与可溶性多糖复合物蛋白的功能性质及结构的影响。结果表明,将黑豆蛋白与可溶性多糖以1∶2的比例混合时,复合物的乳化性最好,此时复合物乳液比较稳定。用不同超声时间处理上述复合物溶液,处理16 min的复合物的乳化性最好,处理8 min的复合物的乳化稳定性最佳。同时随着超声时间的延长,蛋白质二级结构中α-螺旋含量上升,β-折叠下降,说明蛋白质的结构与功能性质有着密切关系。适当的超声处理可以改变黑豆蛋白与可溶性多糖复合物的结构,提高某些功能特性。     

基于SPME-GC-MS分析不同烤制时间新疆烤羊腿表层及内层挥发性化合物

为研究烤制时间对新疆烤羊腿表层和内层挥发性化合物的影响,采用固相微萃取-气相色谱-质谱技术对烤制时间分别为0.5、1、1.5、2、2.5、3 h的烤羊腿表层和内层的挥发性化合物进行分析。结果表明烤羊腿表层和内层分别检测出64 种和55 种挥发性化合物,主要为烃类、醇类、醛类、杂环类、酮类、酯类和酸类。随着烤制的进行,烤羊腿表层的烃类、醇类、醛类、杂环类、酮类、酯类物质的种类和含量均高于内层。1.5 h是烤羊腿产生挥发性化合物的关键点。通过对已检出的烤羊腿特征挥发性风味物质相对气味活度值进行分析得出2.5 h时烤羊腿中特征挥发性风味物质对烤羊腿表层和内层的贡献最大,其中1-辛烯-3-醇、壬醛、(E,E)-2,4-癸二烯醛、辛醛、己醛对烤羊腿的香气贡献较高。     

超声波处理对水溶性猪肝蛋白乳化特性的影响

该研究提取猪肝水溶性蛋白,配制成2.5 mg/mL蛋白溶液,分别以300、360、420、480、540 W的功率超声波处理7 min和以420 W的功率超声波处理4、7、10、13、16 min,然后测定乳化性相关指标。结果表明,超声波对猪肝水溶性蛋白的乳化活性、乳化稳定性、表面张力、界面蛋白种类和吸附量、液滴粒径大小及分布、乳化液乳析指数和分子作用力均有显著性影响,且在超声波功率为420 W、处理时间为7 min时乳化性能最好,乳化性和乳化稳定性分别为45.55 m^2/g和93.32%。综上,适宜功率和时间的超声波处理能有效改善水溶性猪肝蛋白的乳化性,超声波处理改善了蛋白质在水溶液中的分散效果和蛋白质的分子作用力。     

Effects of different ATP contents on phosphorylation level of glycogen phosphorylase and its activity in lamb during incubation at 4 ℃ in vitro

The aim of this study was to investigate the effects of ATP on glycogen phosphorylase activity in lamb during incubation at 4℃ in vitro. Sarcoplasmic proteins from lamb were extracted and treated with different contents of ATP to get three groups of glycogen phosphorylase with low, middle and high ATP content groups, the amount of ATP were 0.5, 2.0 and 2.5 μM per 100 μg protein, respectively. The control group was without ATP adding. The results showed that ATP promoted the phosphorylation of glycogen phosphorylase, and phosphorylation modification promoted its activity. But ATP inhibited the activity of glycogen phosphorylase and ATP preferentially participated in phosphorylation. When ATP concentration was 0.5 μM per 100 μg protein, the effect of phosphorylation modification on the activity of glycogen phosphorylase was equal to the inhibition of ATP. The effect of glycogen phosphorylase phosphorylation on its activity gradually became dominant as incubation time prolonged.