γ射线辐照对猪肉糜加工特性及安全性影响研究

主要研究γ射线辐照处理对猪肉糜加工特性(蒸煮损失、滴水损失、pH值、质构和色泽等指标)的影响。在此基础上,进一步分析辐照处理对猪肉糜中脂质和蛋白氧化的影响,最后研究辐照对肉糜加工过程不同化学危害物(杂环胺、多环芳烃等)形成的影响。最后综合上述相关研究结果,综合评价γ射线蝠照对肉糜加工特性的影响。结果表明:低剂量的辐照处理对猪肉糜的加工特性不产生显著性影响,高剂量的辐照处理会导致猪肉糜加工后色泽L~*值显著减小,b~*值显著增大,同时蒸煮损失和滴水损失明显增大,嫩度值变小,脂肪氧化和蛋白氧化程度均明显增大;低剂量的辐照处理对猪肉糜的加工后生成多环芳烃和杂环胺无显著性影响,高剂量的辐照处理后猪肉糜加工生成多环芳烃和杂环胺明显增多。     

辐照对食品营养成分的影响

将辐照技术应用于食品货架期和食品冷藏期,不仅仅能够延长食品的保质期,而且在一定程度上提高了食品的卫生质量,对于食品的工艺也有所改变。本文主要从辐照对食品中蛋白质、维生素及脂肪的影响进行了概述,探讨辐照技术在工业生产领域中的应用。     

电子束辐照对真空包装冷鲜猪肉品质的影响

为研究电子束辐照对冷鲜猪肉品质的影响,以真空包装探究冷鲜猪肉用电子束(1.9,3.8,5.6 k Gy)辐照后理化指标(TBARS值、酸价、颜色、保水性)和感官特性在贮藏温度4℃条件下的变化情况。结果表明:随着辐照剂量的增加,真空包装冷鲜猪肉的脂肪氧化程度未发生显著变化;辐照后,冷鲜猪肉的酸价降低,感官品质优于未辐照组,然而其保水性降低,并出现明显异味。随着贮藏时间的延长,辐照异味有所降低。综合考虑各项指标,低剂量的电子束辐照对真空包装冷鲜猪肉影响较小。用1.9 k Gy的电子束辐照,真空包装冷鲜猪肉的品质最优。     

中国研究不同剂量辐射处理对鲜肉及其贮藏过程中脂质氧化、颜色和挥发性风味物质变化的影响

<正>辐照是一项能够有效维持食品微生物安全性的非热加工技术,但是当食品经辐照处理后,会有自由基的产生,这些自由基会导致脂肪和蛋白质等肉制品食品组分的变化,因此,在肉制品加工中的应用有很大的局限性。已有研究表明,辐照食品的化学和品质变化与自由基反应相关,如脂肪和蛋白质的氧化,会导致肉制品的颜色和风味的变化。中国科学家对不同剂量辐射处理对鲜肉及其贮藏过程中脂质氧化、颜色和挥发性风味物质的影响,进行研究。实验设计辐照剂量为0、3、5、7 kGy,贮存条件为4℃,测定参数包括辐照变味程度、     

腌鱼制品中乳酸菌及其对品质影响的研究进展

随着人们生活水平的提高,饮食结构和消费习惯的变化,人们对食品品质的要求也越来越高,改变传统食品加工方式,开发低盐、健康、安全的腌制品加工技术势在必行。腌鱼是我国重要的传统水产食品,具有咸鲜相宜、风味独特的特点,深受国内外消费者的喜爱。腌鱼加工过程中,蛋白质和脂肪被肌肉中的内源酶和微生物酶降解为小肽、氨基酸和脂肪酸等,这个过程中发生的蛋白水解、脂肪氧化和脂肪水解三大反应决定了腌鱼制品的营养品质。而乳酸菌是腌制食品自然发酵中的常见菌种之一,会参与一系列的物理化学反应,从而改善食品的营养特性,提升产品品质和安全性,赋予产品独特的风味, 并延长食品保质期,在食品行业被广泛应用。本文综述了国内外腌鱼制品中的乳酸菌及其对产品品质的影响,为创新开发新型腌鱼制品提供理论依据,也为传统食品的技术改造提供新的思路。     

肌肉蛋白质乳化凝胶及保油保水性机理研究进展

肌肉蛋白质乳化及热诱导凝胶特性是肉糜类制品加工的基础,它直接关系到制品的流变学特性、质构、保油保水性和口感等。文中主要从分子及化学作用力角度简述了肌肉蛋白质乳化脂肪、热诱导凝胶及保油保水性机理,以期为乳化凝胶类肉制品加工提供一定的理论依据。     

基于近红外光谱的猪肉蛋白质及脂肪含量检测

蛋白质及脂肪是猪肉的重要营养成分。随着人们对饮食健康的要求越来越高,对猪肉蛋白质及脂肪含量快速检测也成为必然。通过近红外光谱技术对猪肉进行光谱数据采集,将光谱数据分为校正集样本和预测集样本,然后,在MATLAB中利用多元散射校正(MSC)与均值中心化相结合的方法进行光谱预处理并采用联合区间偏最小二乘方法(SiPLS)获得猪肉蛋白质及脂肪含量与光谱数据特征之间的对应关系,从而定量分析猪肉蛋白质及脂肪含量。实验结果表明,建立的SiPLS检测脂肪及蛋白质含量预测模型的最优组合分别为划分为20个光谱区间并联合4个子区间和9个主成分因子,和划分19个光谱区间并联合4个子区间和10个主成分因子。其预测集的相关系数分别为0.9798、0.9788,交互验证均方根误差分别为0.228,0.241。研究结果表明,利用近红外光谱结合SiPLS算法可以快速准确检测猪肉蛋白质与脂肪含量。     

烧鸡加工过程中营养成分变化研究

研究了传统工艺和腌制工艺加工的烧鸡煮制过程中水分、蛋白质、脂肪和氯化钠含量的变化,结果表明,不同处理加工的烧鸡煮制过程中水分含量呈下降趋势,蛋白质和氯化钠含量随煮制时间的延长而升高,脂肪含量煮制1h时最高,其后随煮制时间的延长而下降;烧鸡经腌制处理可提高成品率,降低盐分含量,但对煮制过程中蛋白质和脂肪含量影响不大。     

电子束辐照对冷鲜猪里脊肉品质及蛋白特性的影响

为探究电子束辐照对真空包装冷鲜猪肉品质的影响,取屠宰后72 h成熟的猪里脊,在高能电子加速器下辐照,4℃贮藏10 d,评估不同辐照剂量(2.0、4.0、6.0 k Gy)和贮藏时间(0、5、10 d)条件下微生物学,生物化学和蛋白特性的变化。在贮藏第0天,冷鲜猪肉的菌落总数为4.74(lg CFU/g),辐照处理后,2.0,4.0,6.0 k Gy菌落总数分别减少到2.97、2.83和2.66(1g CFU/g),差异性显著(P0.05);在贮藏前期电子束辐照显著降低了冷鲜猪肉的TVB-N和pH值,但在贮藏后期虽然辐照处理组的TVB-N和pH值低于空白对照组,但二者无显著性差异。辐照处理加剧冷鲜猪肉的脂肪氧化,并使其蛋白质的溶解度和非蛋白氮含量增加,但对于粗蛋白含量无显著性影响。     

营养及饲养条件对猪肉品质影响的研究进展

猪肉是我们膳食中不可缺少的优质蛋白质来源。猪肉品质受品种、年龄、营养状况、性别、屠宰方法、宰后的生物化学变化、加工方法等很多因素的影响,其中营养及饲养条件对猪肉品质有明显影响。本文从饲养状况、饲粮热能水平、饲粮营养成分(包括蛋白质和氨基酸、脂肪、矿物元素和维生素)、生长促进剂(包括重组猪生长激素、β-兴奋剂、L-肉碱、甜菜碱、莫哈夫丝兰提取物和矿物元素)等方面对猪肉品质影响的研究进展做了综述。     

LIPID AND CHOLESTEROL OXIDATION,COLOR CHANGES,AND VOLATILE PRODUCTION IN IRRADIATED RAW PORK BATTERS WITH DIFFERENT FAT CONTENT1

An emulsion-type product was prepared to determine the effect of irradiation on lipid and cholesterol oxidation, color change, and volatile production in raw pork with different fat contents. Lipid oxidation increased with an increase in fat content or irradiation dose. Irradiated batters had higher cholesterol oxides than nonirradiated, and the major cholesterol oxides formed in irradiated pork batters were 7α- and 7β-hydroxycholesterol. Hunter color a- and b-values of raw pork batters were decreased by irradiation regardless of fat content. Irradiation increased the amount ofvolatiles significantly. Although lipid oxidation of high fat products (10 and 15% fat) was higher than that of low fat products (4%), high fat products did not always produce greater amount of volatiles. In summary, irradiation increased lipid and cholesterol oxidation, volatiles production and had detrimental effects on the color of raw pork batters under aerobic condition.     

Collagen content of some Australian canned meats

Eleven manufacturers supplied 146 samples of canned corned beef, corned beef with cereal, ham, cured pork shoulder and comminuted ham products. All cans were analysed for salt, moisture, fat, protein and collagen. The mean collagen content ranged between 0.99 and 4.08%. These results are discussed in relation to current international interest in establishing minimum limits for collagen-free meat protein in processed meat products.     

Effect of gamma or beta radiation on Salmonella DT 104 in ground pork

Mixtures of six Salmonella Typhimurium DT 104 strains were inoculated into three ground pork products to determine the effect of fat content on the radiation resistance of Salmonella DT 104. The ground pork products were 90% lean, 50:50 fat:lean, and 100% fat. Inoculated products were irradiated using a gamma radiation source in a self-contained 137Cesium irradiator or a 10 MeV accelerator producing electrons (e-beam). The radiation D10-values (dose required for a 90% inactivation of viable CFU) for Salmonella DT 104 inoculated into 90% lean ground pork, 50:50 fat/lean ground pork, and 100% pork fat and subjected to beta radiation were 0.42 kGy, 0.43 kGy, and 0.43 kGy, respectively. The corresponding radiation D10-values for Salmonella DT 104 subject to gamma radiation were 0.56, 0.62, and 0.62 kGy, respectively. There was no statistical significant difference (P = 0.3) in radiation D10-values for Salmonella in the three products subject to either radiation treatment. Therefore, fat content had no effect. There was a significant difference (P = 0.001) between the radiation D10-values obtained with the two radiation sources. The radiation D10-values were within the reported range for irradiation destruction of Salmonella contaminated raw meat products.     

PROCESSING, CHEMICAL, SENSORY AND PHYSICAL PROPERTIES OF BACON-CHOPPED AND FORMED, MADE FROM PORK, BEEF, MUTTON AND CHEVON

By extruding alternating layers of chopped lean and fat tissue, bacon-chopped and formed (CF) products were processed from pork, beef, mutton and chevon lean and beef fat. Slabs processed from beef materials had less weight loss and changes in width and thickness during smoking than the other formulations. Various sensory and consumer panels found pork-bacon-CF product to rate highest among the four formulations for tenderness, flavor and overall satisfaction. This formulation was rated as being closest in sensory traits to commercial bacon. Chevon and mutton bacon-CF products were found to be less desirable in flavor. Inclusion of pork lean and fat with chevon and mutton lean can potentially improve the acceptability of bacon-CF processed with lean from these two species. However, this process and product appears promising as methods of increasing consumption of underutilized meat animal species.     

Effects of dietary soybean oil on lipid and protein oxidation in pork patties during chill storage

The effect of dietary soybean oil on lipid and protein oxidation in low and high fat pork patties made from quadriceps femoris during chill storage in a high oxygen atmosphere packaging (80% O(2)/20% CO(2)) in the dark for 7 days was investigated. Pigs were fed either a standard diet or a diet added 2% soybean oil. After slaughter high fat pork patties were prepared for both feeding regimes by addition of back fat from pigs fed the same diet whereas low fat pork patties were prepared without addition of back fat. The 2% soybean diet increased the amount of unsaturated fat in the pork. Secondary lipid oxidation products determined as thiobarbituric acid reactive substances (TBARS) were found to increase in the pork patties with increased unsaturated fat. Increased unsaturated fat in the pork patties had no effect on protein oxidation determined as free protein thiol content and protein carbonyl content. A small, but significant increase in protein oxidation was found in the high fat pork patties independent on dietary fat. In conclusion, protein oxidation is unaffected by dietary fat in pork patties during chill storage for periods normally used in retail trade, and lipid and protein oxidation are not coupled under these conditions.     

辐照肉品的安全性

辐照是利用原子能射线的辐照能量对食品杀菌处理来保存食品的一种物理方法。辐照技术可以减少肉制品的损失,保证肉制品的卫生质量和安全,对提高人们的生活质量,增加肉制品的附加值,促进食物安全有重要的意义。本文综述了辐照技术的优点,辐照技术在肉制品中的应用及辐照肉制品的安全性。     

猪肉腌制过程中亚硝酸钠添加量对其质构的影响

亚硝酸盐是腌腊肉制品中常用的食品添加剂,具有发色、抑菌、改善风味和质构等作用。本试验应用质构剖面分析方法(TextureProfileAnalysis,TPA)对猪肉腌制过程中不同亚硝酸钠添加量对其质构的影响做了初步研究,发现随着腌制时间的增加,硬度(Hardness)、胶黏性(Adhesiveness)、弹性(Springiness)和咀嚼性(Chewiness)增加,而粘聚性(Cohesiveness)和回复性(Resilience)减小。添加亚硝酸盐后,硬度和咀嚼性增加显著(p<0.05),胶黏性和弹性增加不显著(p>0.05);粘聚性减少不显著(p>0.05),回复性减少显著(p<0.05)。猪肉腌制过程中化学成分变化显示,水分、脂肪、蛋白质、胶原蛋白和亚硝酸盐都有降低趋势。通过化学成分含量与质构指标的相关分析,水分含量与胶黏性、回复性和弹性的相关性较高(分别为r=0.891,r=-0.770,r=-0.770:p<0.05),是影响质构的主要因素;亚硝酸盐与弹性显著负相关(r=-0.808,p<0.05),而与其它质构指标相关系数较低;胶原蛋白含量与回复性的相关性较高(r=0.740,p<0.05);脂肪、蛋白质含量与质构指标的相关系数较低。     

PCR方法快速鉴别食品中肉的种类

本文针对食品中肉成分种类鉴别开发了一种快速灵敏的PCR检测方法,可检测食品中是否存在猪肉、牛肉、羊肉以及鸡肉等成分。采用微波助提法提取样品中DNA,简化了前处理步骤,可在短时间内完成从多种不同类型肉与肉制品中提取肉成分DNA。为了评价方法的可靠性与灵敏度,猪肉以及掺入了不同比例浓度猪肉成分的食品样品采用本方法进行了核酸提取与PCR分析。检测结果表明,方法可检测出低至含有0.5%浓度的猪肉成分的混合样品。随机抽取50份不同类型的市面食品样品,检测出5份食品含有猪肉成分,7份食品中含有牛肉成分,5份食品中含有羊肉成分。该样品前处理方法、DNA提取方法以及PCR检测方法可广泛应用于食品中肉成分种类的检测鉴别。     

Determination of Porcine Contamination in Laboratory Prepared dendeng Using Mitochondrial D-Loop686 and cyt b Gene Primers by Real Time Polymerase Chain Reaction

The identifications of species in meat products have created interests since these foods became the target of forgery and fraud in the market. The presence of pork in food products is not allowed for the Muslim community. Hence, an analysis is necessary to detect the presence of pork in processed meat products, such as in dendeng (dried meat) product. Real time polymerase chain reaction using mitochondrial displacement loop686 and cytochrome b (cytb) gene primers was used to identify specific pork DNA among other four types of DNA species; namely beef, chicken, goat, and horse. This method was also used to identify pork DNA in the laboratory processed pork-beef dendeng as well as commercial dendeng from market. The results showed that real time polymerase chain reaction using displacement loop686 and cytb gene primers were able specifically to distinguish between pork DNA and the other species. The lowest concentration of 0.5% of pork DNA in a mixture of pork-beef processed products of dendeng was able to be detected by both primers with the product amplification of 114 and 134 bp (base pair) for the displacement loop686 and 149 bp for cytb gene, respectively. High sensitivity was also obtained when both primers were applied with the lowest detection limit of 5 pg/µL pork DNA. The results of the six commercial dendeng amplification using both primers showed no amplified products present, meaning that these products do not contain porcine DNA.     

微滴式数字聚合酶链式反应精准定量检测羊肉中掺杂猪肉

以羊和猪的单拷贝持家基因DNA复制蛋白A1为靶基因设计合成了适用于微滴式数字聚合酶链式反应的特异性引物和探针,通过理论推导获得了单位质量两种肉基因拷贝数之比的固定值,并进行了验证,据此将样品中羊肉和猪肉的拷贝数转换为相对质量分数,从而建立了羊肉中掺杂猪肉的精准定量检测方法。该方法可以很好地应用于羊肉中掺杂猪肉的含量检测,猪肉的最低定量限为1%,在5%~80%范围内绝对误差小于±1.30%,相对误差小于±10%,定量结果准确、重复性高,可以为肉类掺假的监管工作提供有力的技术参考。