微量元素铬对猪肉质性状的影响

将18头70kg左右的杜长大三元杂交猪随机分为2个处理组,分别饲喂基础日粮和实验日粮,实验日粮为基础日粮中添加吡啶羧酸铬,铬在日粮中的添加浓度为200μg/kg。研究铬对肥育猪肉质性状的影响。结果表明:在猪肥育期日粮中添加铬,可以显著提高眼肌面积（LMA）、宰后24h肌肉pH和肌内脂肪（IMF）含量（P<0.05）,减少滴水损失和血清游离脂肪酸（NEFA）含量（P<0.05）。通过对H-FABP基因表达量的分析表明,铬显著提高了肌肉组织中H-FABP基因表达量（P<0.05）,H-FABP基因表达量与IMF含量呈正相关,相关系数为0.826（P=0.042）;与NEFA含量呈负相关,相关系数为-0.753（P=0.046）。研究表明,铬能够显著提高肌肉组织中H-FABP基因表达量,减少血清NEFA含量,改善肉质性状。      

能量水平对猪H-FABP 基因表达量及肉质的影响

将18 头60kg 左右的杜长大三元杂交猪随机分为两个处理组,分别饲喂高、低能量水平两种日粮,研究不同能量水平对H-FABP 基因表达量及肉质性状的影响。结果表明：高能量水平有促进H-FABP 基因表达的趋势(P ＞ 0.05),高能量水平显著提高了背膘厚(BFT)和肌内脂肪(IMF)含量(P ＜ 0.05)。猪H-FABP 基因表达量与IMF 含量呈显著正相关(P ＜ 0.05);IMF 含量与BFT 呈显著正相关(P ＜ 0.05)。这表明能量水平对H-FABP 基因表达量有一定的影响,可以影响肉质。     

荣昌猪和杜洛克猪肉质及营养价值的比较分析

以脂肪型的荣昌猪和瘦肉型的杜洛克猪为研究对象,比较分析2 个品种之间背最长肌的肉质、氨基酸、脂肪酸和微量元素含量差异。结果显示：荣昌猪的肌内脂肪含量、肉色和大理石纹显著高于杜洛克猪（P＜0.05）,剪切力显著低于杜洛克猪（P＜0.05）;荣昌猪背最长肌中丝氨酸、丙氨酸、精氨酸、异亮氨酸、酪氨酸、总氨基酸含量和呈味氨基酸总量显著高于杜洛克猪（P＜0.05）;荣昌猪背最长肌的饱和脂肪酸含量显著低于杜洛克猪（P＜0.05）;单不饱和脂肪酸含量显著高于杜洛克猪（P＜0.05）;荣昌猪背最长肌中微量元素Co、Mn、Cr、Se和Zn含量均显著高于杜洛克猪（P＜0.05）,微量元素As和Mo含量显著低于杜洛克猪（P＜0.05）。结果表明,脂肪型的荣昌猪在肉质及营养价值方面总体优于瘦肉型的杜洛克猪,为中国地方猪种遗传资源的保护及开发利用提供了理论依据。     

纯种猪与杂交猪肉质性状及营养价值比较研究

为研究杂交对猪肌肉肉质、激素、脂肪酸、矿物元素含量和肉质相关基因表达水平的影响,实验选取同一饲养条件下,180日龄的纯种长白猪、纯种约克夏猪及长白猪×约克夏猪二元杂交猪各6头,屠宰后采集背最长肌。结果表明:二元杂交猪与长白猪和约克夏猪相比,其肌肉滴水损失、粗脂肪含量、胰岛素含量、多种矿物元素含量和肉质相关基因(RYR1、CAST、IGF2、PPKAG3和MC4R)表达水平显著升高(P<0.05);而其剪切力、水分含量和多不饱和脂肪酸含量显著降低(P<0.05)。杂交对猪的肉质性状和营养成分含量影响显著,但不能判断对其综合影响是否有益。     

宰前配方对夏季杜长大肥育猪肉质性能的影响初探

试验对20头杜长大肥育猪作了宰前40d的配方调整，试验结果提示，VE及其配伍的维生素和矿物质配方，可以改善试验猪的超氧化物歧化酶(SOD)活性和宰后24h黄度值，对改善货架期肉的抗氧化性能有一定的作用。     

蜂胶对货架期猪肉肉质的影响

以不同浓度的蜂胶乳浊液浸泡货架期猪肉眼肌,测定其pH值、拿破率、烹饪损失、滴水损失、L*、a*、b*值等七项指标,比较在不同浓度时对肌肉的肉质参数的影响.试验结果表明,低浓度的处理组的拿破率高于其它各组,但滴水损失也比高浓度的处理组要高;蜂胶处理的肉样L*值较低,a*较高,有改进肉色的作用.     

荣昌猪肉质的硬度分析研究

选择不同体重荣昌猪的不同部位肌肉块,采用系统分组试验设计,测试不同体重、不同新鲜程度下不同部位的肌肉块在不同肌纤维方向的硬度。结果表明：肉质硬度以横向肌纤维最大,切向肌纤维次之,纵向肌纤维最小;肉的硬度随着猪体重增加而降低（p〉0．05）;不同部位间肉块的硬度值有极显著差异（p〈0．01）;肉块的硬度值随着贮藏时间延长有先上升后下降的趋势（p〉0．05）。     

影响猪肉质的主效基因和候选基因

猪肉的品质问题已经引起了生产者和消费者的普遍关注,肉质性状直接影响到肉品的食用价值和经济价值。分子生物学技术的快速发展也促进了人们对于影响肉质相关基因的重视和研究。本文综述了与肉质相关的主效基因（Major Gene）烷氟基因（Hal gene）、单磷酸腺苷蛋白激酶（AMPK）γ3亚基基因（PRKAG3）和酸肉基因（Rendement Napole Gene,RN）以及脂肪酸结合蛋白基因（Fat Acid Binding Protein FABPs）、激素敏感脂肪酶（Hormone-Sensitive Lipase,HSL）基因和脂蛋白脂肪酶（Lipoprotein Lipase,LPL）基因等候选基因（candidate gene）的研究进展。      

皮特兰、斯格、PIC猪肉质理化指标的比较

通过测定皮特兰猪、斯格猪、PIC猪的乳酸脱氢酶、游离脂肪酸、肌酸激酶、丙氨酸氨基转移酶、天门冬氨酸转氨酶等指标,来评定各品种之间肉质的差异。实验结果表明:斯格猪和PIC猪肌肉中乳酸脱氢酶活性显著低于皮特兰猪(P<0·05);皮特兰猪和斯格猪肌肉中游离脂肪酸含量以及肌酸激酶活性显著高于PIC猪肉(P<0·05);斯格肌肉中ALP活性最大,AST活性最小;PIC猪肌肉中ALP活性最小,皮特兰猪肌肉中AST活性最大。综合各项指标,斯格猪抗应激力较强,肉质较好,PIC猪次之,皮特兰猪最差。      

皮特兰、斯格、PIC猪肉质理化指标的比较

通过测定皮特兰猪、斯格猪、PIC猪的乳酸脱氢酶、游离脂肪酸、肌酸激酶、丙氨酸氨基转移酶、天门冬氨酸转氨酶等指标,来评定各品种之间肉质的差异.实验结果表明:斯格猪和PIC猪肌肉中乳酸脱氢酶活性显著低于皮特兰猪(P<0.05);皮特兰猪和斯格猪肌肉中游离脂肪酸含量以及肌酸激酶活性显著高于PIC猪肉(P<0.05);斯格肌肉中ALP活性最大,AST活性最小;PIC猪肌肉中ALP活性最小,皮特兰猪肌肉中AST活性最大.综合各项指标,斯格猪抗应激力较强,肉质较好,PIC猪次之,皮特兰猪最差.     

Meat quality: Influence of fatness of pigs on the eating quality of pork

The eating qualities of pork from the longissimus dorsi muscles of pigs showing a wide variation in fatness (10-40 mm, back fat thickness) were assessed by taste panel after either the excised muscle had been grilled or a complete loin joint had been roasted. The average panel scores for texture and juiciness covered a wide range but were not consistently related to fatness. Although meat from fatter pigs tended to be judged more tender in direct comparisons, overall the results did not support the contention that fatness in the carcass is associated with tenderness in the lean meat.     

Effect of processing plant on pork quality

The impact of processing plant on pork quality was studied by assessing pork quality in three commercial plants (A, B, C). Plants differed in the layout of the races, stunning systems (A and B: electrical, C: CO(2) stunning) and chilling systems (A: rapid chilling, B and C: conventional). Factors not related to the processing plants (e.g. genetic background of animals, transport, lairage) were standardized. In total, nine batches of about 150 pigs each were processed. Each batch was purchased at a commercial farm and randomly divided into three groups for delivery to the three processing plants. Meat quality was evaluated by measuring early post-mortem muscle pH and temperature as well as ultimate pH, meat colour (Minolta Chroma Meter and Japanese colour scale), filter paper score (FPS), electrical conductivity (EC) and drip loss. Plant C produced an inferior quality compared to plants A and B: meat was paler (C: 2.8 vs. A: 2.9 and B: 3.0 on the Japanese colour scale) and had higher drip losses (C: 5.2 vs. A: 4.8 and B: 4.9%). Meat colour hardly differed between plants A and B but waterholding properties were best at plant A as indicated by FPS (A: 2.4 vs. B: 2.8 vs. C: 3.3) and EC (A: 5.4 vs. B: 6.4 vs. C: 7.4 mS). It is concluded that processing plant may influence meat quality. Correlations between early post-mortem measurements and meat quality traits were low. Nevertheless, high carcass temperatures and low pH values early post-mortem were shown to lead to inferior meat quality.     

Impact of increasing dietary energy level during the finishing period on growth performance,pork quality and fatty acid profile in heavy pigs

Sixty Duroc × (Landrace × Large White) gilts of 93.5 of body weight (BW) were used to investigate the effect of increasing dietary net energy content (2280, 2350, and 2420 kcal/kg) on growth performance and carcass, meat, and fat characteristics. Animals were intended for dry-cured ham production. Therefore, pigs were slaughtered at 130 kg BW and a minimum fat thickness at Gluteus medius muscle (m. GM) was required. No effect was detected on daily gain or energy intake but feed intake decreased and feed conversion ratio tended to improve as energy increased. Fat depth at m. GM was wider and the proportion of suitable carcasses tended to be greater when energy increased. The treatment had scarce effect on meat and fatty acids. We conclude that 2350 kcal of net energy per kg of feed would optimize the productive and quality responses in gilts when are intended for dry-cured ham production.     

Strategic finishing feeding as a tool in the control of pork quality

A standard diet and two finishing feeding strategies known to reduce muscle glycogen stores were investigated in combination with exercise immediately prior to slaughter in pigs. The objective was to determine the influence of muscle glycogen at slaughter on temperature and pH in post-mortem muscle, the colour, drip loss and Warner–Bratzler shear force of the meat. The muscle glycogen stores were reduced by strategic finishing feeding. In general, pH_{45 min} was higher in muscles from strategically fed pigs compared with control pigs. Exercise also resulted in higher pH_{45 min} in control pigs compared to non-exercised control pigs, while the opposite was seen in muscles from strategically fed pigs. Exercise resulted in higher muscle temperatures in the carcasses irrespective of feeding strategy. pH_{24 h} were higher in M. biceps femoris and M. semimembranosus from exercised, strategically fed pigs compared with the corresponding controls. In contrast, irrespective of feeding strategy no difference in pH_{24 h} was registered in the meat of non-exercised pigs. Drip loss was lower in meat of strategically fed pigs compared with meat of control pigs. Moreover the drip loss was lowest in the meat of non-exercised pigs. The present study shows that strategic finishing feeding has high potential for the control of pork quality.     

Effect of hot-boned pork on the keeping quality of fresh pork sausage

The first experiment evaluated the effect of solid carbon dioxide (dry ice) addition to hot-boned meat, in different proportions, upon the keeping quality of fresh pork sausage patties. Dry ice had some negative effects at levels of 20% to 40%, such as hardening and colour fading of samples, although it increased water-holding capacity of the sausage. In the second experiment three proportions of hot-boned meat and chilled meat were evaluated as a means to extend the retail storage time of fresh pork sausage links. Hot-boned pork was treated by three methods: freezing the meat before grinding, salting and freezing, and salting plus dry ice addition. The results favoured the use of 50% hot-boned meat and 50% chilled meat, for which the lowest hardness and oxidation values were obtained. Microbial counts and hue values showed no significant variation among the three treatments. Salting and freezing hot-boned meat before grinding was the method which produced the best overall quality.     

乳化剂对育肥猪肌肉品质和抗氧化性能的影响

探讨乳化剂对育肥猪肌肉品质和抗氧化性能的影响.结果表明:在育肥猪日粮中添加200 mg/kg乳化剂,对肌肉颜色、pH值、失水率和熟肉率无显著影响(P＞0.05),但试验组滴水损失降低显著(P＜0.05),肌内脂肪提高显著(P＜0.05).与对照组相比,试验组肌肉超氧化物歧化酶活力增加(P＞0.05),丙二醛含量下降(P＜0.05).     

两段式冷却急冷温度对冷却猪肉品质的影响研究

研究了不同急冷温度(-14、-18、-22、-26、-30℃)对冷却猪肉品质的影响。结果表明,急冷温度的变化对冷却肉食用品质有显著影响(p<0.05),急冷温度为-22℃能显著提高冷却肉的保水性,改善色泽和质构,降低胶着性、咀嚼性和硬度,但对黏着性和弹性无显著影响;宰后45min胴体温度和pH对冷却肉保水性有预测作用,pH45min与冷却猪肉失水率呈负相关,宰后45min的胴体温度与失水率呈正相关。     

Effects of triticale-based diets on finishing pig performance and pork quality in deep-bedded hoop barns

Effects of triticale diets on pig performance and pork quality were evaluated in summer and winter. Diets were: corn-soy, 40% triticale, or 80% triticale. Pigs (72 kg) were fed 49 d. Loins were evaluated for meat and fat quality and sensory evaluation. Average daily gain decreased as triticale inclusion increased (P < 0.01). Feed intake was similar. Pigs fed corn-soy had the greatest and those fed 80% triticale had least gain:feed ratio (P < 0.05). In summer, pigs fed corn-soy had largest and those fed 80% triticale diet had smallest loin muscle area (P < 0.05) based on ultrasound scan. During summer, ultimate pH was higher (P ? 0.001) and, loin purge and shear force were lower (P < 0.05). Diet did not affect sensory evaluation or fatty acid profile of loins. During summer, total MUFA were more and total PUFA were less (P ? 0.01). Triticale fed to pigs in hoop barns slightly decreased growth without compromising pork quality.     

Effect of substituting pork backfat with rind on quality characteristics of pork sausage

A study was conducted in which pork backfat in pork sausage was replaced with rind at 0, 33, 66 and 100% levels. The high moisture and high protein content of rind consequently influenced the moisture and protein content of the final products. The fat level decreased with increase in the level of rind in the sausage. The lowest fat content of 7.99% was recorded on batch 4 sausage with 100% rind replacement level. Replacement of pork backfat with rind decreased refrigeration and cooking weight losses. The values obtained for sensory properties decreased with increase in the level of rind in the sausage. Up to 66% pork backfat can be replaced with rind in pork sausage without adverse effect on processing yield.