金华火腿生产过程中脂质氧化及脂肪氧合酶变化特点研究

60只重量为6.2～6.9kg的原料腿按传统工艺加工金华火腿.分别于原料腿、盐后、晒后、成熟中期、成熟结束、后熟-1和后熟-2七个工艺点随机取5只腿的股二头肌为样品,分析TBA值、羰基值、共轭二烯值及脂肪氧合酶活力的变化,同时用响应曲面法研究加工过程中主要因子对脂肪氧合酶活力的影响.结果显示TBA值在晒后达到最高,羰基值、共轭二烯值在盐后达到最高,在其它工艺步骤变化不明显.脂肪氧合酶活力从原料腿的8.00U/min·g蛋白上升到盐后的12.55U/min·g蛋白,之后不断下降,至后熟-2酶活为4.87U/min·g蛋白.温度、盐含量和硝酸盐含量是脂肪氧合酶活力的显著影响因子,且温度与盐和硝酸盐含量之间的交互作用对酶活产生显著影响.利用所得回归方程预测加工过程中的实际酶活在成熟中期达到最高,该酶活可解释20%左右的脂肪氧化水平,说明生产过程中脂肪氧合酶在脂肪氧化中不起主导作用,脂肪氧化以自动氧化为主.     

金华火腿加工过程中肌肉肌内脂的水解变化研究

研究了金华火腿股二头肌 (bicepsfemoris)肌内脂肪在加工过程中不同时期的水解变化情况。肌内脂使用氯仿 甲醇溶液提取 ,采用固相萃取法将中性脂 (主要为甘油脂 )、游离脂肪酸和磷脂分离 ,用毛细管气相色谱分别分析甘油脂、游离脂肪酸和磷脂脂肪酸的种类与比例。通过比较不同时期样品的色谱结果 ,发现在金华火腿原料中磷脂脂肪酸的不饱和脂肪酸百分含量较高 ,尤其是多不饱和脂肪酸的含量高达 4 9 2 2 %。且在金华火腿成熟过程中 ,磷脂水解作用显著 ,而甘油脂脂肪酸百分比例比较稳定 ,说明甘油脂水解作用相对较弱。     

盐含量对金华火腿中脂质水解的影响

考察盐含量对金华火腿中的内源酶活力及游离脂肪酸含量的影响.将原料腿分成2组,分别进行低盐(8%)和高盐(浓度12%)处理.取原料腿、腌制结束期、风干结束期、成熟1期、成熟2期、后熟期的股二头肌部位分别测定其中盐含量、内源酶活力和游离脂肪酸的含量.结果显示:在整个生产工艺中,盐含量不断升高,低盐样品从0.19%上升到8.42%,高盐样品从0.19%上升到9.77%:内源酶活力不断下降,且高盐处理的样品的内源酶活力低于低盐处理样品;总的游离脂肪酸含量呈现上升趋势,其中棕榈酸、油酸和亚油酸是主要的脂肪酸,亚油酸是重要的风味前体物质.盐含量对脂质水解作用的影响不大.     

金华火腿生产过程中风味成分的变化

取60条杂交猪后腿作为原料，按金华火腿传统生产工艺进行生产，分别在原料、盐后、晒后、成熟中期、成熟结束、后熟（1）、后熟（2）工艺段随机取5条腿的股二头肌作为样品进行风味成分检测．结果显示：原料腿和盐后腿中检出89种风味物质，晒后腿中检测出90种风味物质，成熟中期和成熟结束腿中分别检测出91种和96种风味物质，在后熟（1）和后熟（2）工艺段分别检测出93种和94种风味物质．这些成分可归类为：烷烯烃、芳香烃、醇、醛、酮、酸、酯、含氧杂环化舍物、含氮化合物、含硫化合物、含氯化舍物、酰胺和萜烯类等物质，其生产过程中的变化规律不同．在金华火腿产品的风味成分中，醛类占化舍物总数的45．07％，酸占18．39％，醇占13、93％，酮占9．00％．主成分分析显示，第一主成分主要由5种直链醛组成，第二主成分主要由5种直链醇和支链醇、2种支链酮、甲苯、已烷等组成．第一和第二主成分总计解释了金华火腿风味成分变化总方差的90．6％。     

金华火腿传统加工过程中的脂肪氧化研究

取0、30、62、160和240d的金华火腿,提取肌内脂肪和皮下脂肪,分别测定脂肪中各组分的含量和氧化指标。结果表明,肌内脂肪中磷脂含量较多,皮下脂肪中甘油酯含量较多;在金华火腿加工过程中,肌内脂肪和皮下脂肪的酸价一直上升,过氧化值、羰基价和TBA值有升有降,但总体呈上升趋势,脂肪氧化程度不断增强。同时发现,肌内脂肪比皮下脂肪的氧化程度更高。     

金华火腿现代化工艺过程中失重情况研究

采用现代化工艺加工金华火腿,研究了不同原料腿加工过程中的失重变化规律。结果表明,随着加工进程的不断进行,火腿失重率总体呈现上升趋势。各加工时期前期失水速度快,后期较慢;皮下脂肪较厚的原料腿在加工前期易于脱水;重量较大的腿不易脱水失重。到第一成熟期间各处理火腿的总失重率均达到24％的临界点,在后续的熟化过程中,不用考虑失重对火腿的影响,只需考虑风味的形成。     

金华火腿生产加工中HACCP的应用

为了保证金华火腿产品质量安全,对金华火腿生产过程中的各个环节可能存在的潜在危害进行了生物的、化学的、物理的危害分析,根据HACCP的原理确定相应的关键控制点（CCP）和关键限值,并制定了相应的预防措施,建立了监控方法,将生产过程中的危害因素降低到最低程度。     

金华火腿传统加工过程中的脂肪氧化研究

取0、30、62、160和240d的金华火腿,提取肌内脂肪和皮下脂肪,分别测定脂肪中各组分的含量和氧化指标。结果表明,肌内脂肪中磷脂含量较多,皮下脂肪中甘油酯含量较多;在金华火腿加工过程中,肌内脂肪和皮下脂肪的酸价一直上升,过氧化值、羰基价和TBA值有升有降,但总体呈上升趋势,脂肪氧化程度不断增强。同时发现,肌内脂肪比皮下脂肪的氧化程度更高。      

金华火腿防氧化的研究

报告金华火腿色变的机理和防哈措施。指出应从生猪的宰前管理开始，直至胴体处理、腌制、发酵、分割包装等各个环节严格把关，控制氧分压和湿度，方能保持火腿固有的色泽和风味。     

金华火腿工艺过程蛋白质水解及其相关性研究

本文通过对金华火腿工艺过程总氮、非蛋白氮及游离氨基酸的分析研究,来确定其蛋白质分解与工艺过程产品水分、NaCl含量及温湿度条件的相关性;结果表明:工艺过程中非蛋白氮和游离氨基酸的变化与工艺过程湿度和产品水分的降低、温度和NaCl含量的提高呈正相关,且蛋白质在工艺过程中发生了持续降解。     

Biochemical changes during processing of traditional Jinhua ham

Jinhua ham is the most famous traditional meat product of China and one of the most famed dry-cured hams in the world. Its processing consists of six stages: green ham preparation, salting, washing and sun-drying and shaping, ripening, and post-ripening. Intense proteolysis and lipolysis occur during processing period. As a result, the content of free amino acids in final ham products is 14-16 times that of green ham, and 191 volatile compounds have been identified during processing, which make a major contribution to the flavor of Jinhua ham.     

Effect of intensifying high-temperature ripening on lipolysis and lipid oxidation of Jinhua ham

The orthogonal experiment for fermenting-ripening process was carried out to effectively shorten the process time of Jinhua ham by intensifying high-temperature ripening. Lipolysis and lipid oxidation in the ham were affected by the process time, temperature and salt content during processing. Intensifying high-temperature ripening could accelerate the lipolysis and lipid oxidation. Both saturated and unsaturated free fatty acids (FFAs) were steadily increased with temperature rising (p < 0.01). The daily-increment of total FFAs in the muscle of modern process products was significantly higher than that in the traditional ones (p < 0.01) and kept at a high level through high-temperature ripening. TBARS in ripened hams was remarkably lower than that in traditional products (p < 0.01). These results explained that longtime high-temperature (35-37 °C) ripening could effectively promote lipolysis, decrease TBARS value and accelerate the development of flavor in Jinhua ham.     

Proteolysis in biceps femoris during Jinhua ham processing

Sixty experimental Jinhua hams were processed by a traditional method. The nitrogen fractions and free amino acids in biceps femoris were analyzed. Intense proteolysis was found in ham muscle and totally more than 10% of muscle proteins were degraded during the course of Jinhua ham processing. The proteolytic index of Jinhua ham was between 14 and 20. Both insoluble and soluble proteins were degraded to some degree and the later showed more intense degradation. In the soluble fraction, the percentage of non-protein nitrogen (NPN) increased gradually whereas that of protein nitrogen decreased during processing (P<0.05). However, very small amount of peptides larger than 1kDa was accumulated during the whole course of processing, which proved that intense degradation reactions were also happened to them, especially at the post ripening stage when dramatic decrease of nitrogen fraction from all the peptides larger than 1kDa was found. As a result, more than 90% of the NPN products from muscle proteolysis were free amino acids and peptides of MW less than 1kDa that might make important contribution to Jinhua ham taste and provide precursors for the generation of volatile flavor compounds in ham muscle. The pattern of muscle proteolysis coincided with the reported changes of muscle proteolytic enzymes during processing, seemingly indicating that the enzymes could have played important roles in ham muscle proteolysis.     

金华火腿汁提取工艺研究

文章对金华火腿汁的最佳提取条件进行了研究,结果表明提取时间为12h、提取温度80℃、加水量1：3是金华火腿汁的最佳提取条件。     

传统金华火腿生产技术面临的问题及对策

金华火腿是我国著名的传统肉制品。随着社会生活的进步,消费观念的转变,生活方式的改变,金华火腿传统生产技术及产品面临以下问题:1)腌制用盐量过大,导致产品含盐量过高;2)用于发色、防腐的硝酸盐对人体健康有害;3)国家、行业标准落后,存在过低过宽的问题;4)质量检测技术落后;5)产品食用不方便。为解决以上面临的问题,笔者有几点建议:1)采用控温控湿设备,控制食盐渗透速度;按原料腿只重组别分别用盐;采用粗细颗粒合适的腌制用盐及托盘腌制等更能科学控制用盐的腌制方式;2)在腌制盐中添加一些粉状葡萄糖等进行护色,以取代硝酸盐的作用;3)对现有SB/T10004—92《中国火腿》和GB/T19088—2008《地理标志产品金华火腿》进行修订;4)建议引入电子鼻与计算机相结合技术,对香味质量进行信息化处理,通过与储存的数据进行比对,得到香味质量的量化等级;5)增加分割包装的类型,以满足不同顾客的需要。     

低钠传统金华火腿加工过程中理化特性的变化

为了降低传统金华火腿中钠含量,本研究采用与食盐相比钠含量降低了40%~50%的新型低钠盐和食盐制备传统金华火腿,对比加工过程中低钠盐和食盐对火腿水分含量、水分活度、p H、钠及钾含量、蛋白降解指数、TBA值、色泽和感官品质的影响。结果表明:在加工过程中,低钠组成熟后期水分含量为43.86%,与食盐组差异不显著(p>0.05),成熟后期食盐组p H显著低于(p<0.05)低钠盐组,成熟后期低钠盐组蛋白降解指数比食盐组高14.71%。终产品中低钠组TBA值显著高于食盐组(p<0.05),终产品钠含量降低了52.94%,且两组的各项感官指标均无显著差异(p>0.05)。低钠金华火腿在保证了火腿传统风味品质基础上,又降低了钠的含量。      

金华火腿特征风味物质研究进展

金华火腿是我国传统的干腌火腿,以其特殊的风味而著称。通过对金华火腿及其它干腌火腿主要风味物质、形成机理、提取及鉴定方法等研究现状的综述,表明对金华火腿特征风味物质的深入研究有利于了解风味物质形成规律,为金华火腿加工工艺控制及火腿调味料开发应用提供理论基础。     

金华火腿水溶物的滋味成分分析

对金华火腿水溶物中的可溶性糖、有机酸、无机盐、核苷酸、氨基酸和小分子肽等滋味成分进行了初步的分析,并采用味道强度值（TAV）法评价这些滋味成分对火腿的贡献,结果发现,Na+、K+、Ca2+和PO3-4等无机盐;核糖、木糖、葡萄糖、阿拉伯糖和甘露糖等中性糖;乳酸、乙酸和酒石酸;Glu、Ala、Val、Lys和Met五种氨基酸,对火腿滋味贡献较大;火腿提取物中大部分是相对分子质量<1000u的肽,它们共同作用构成了火腿独特的鲜甜滋味,此研究为火腿的呈味研究以及调味料的开发提供理论基础。      

Changes in the volatile flavour components of Jinhua ham during the traditional ageing process

Changes in volatile flavour compounds of Jinhua ham were studied during the traditional ageing process of sun‐drying, loft‐ageing and post‐ageing. About seventy‐eight volatile compounds were tentatively identified, including aldehydes (ten to fifteen), carboxylic acids (eight to ten), alcohols (thirteen to fourteen), ketones (eight), esters (eight to ten), aromatic hydrocarbons (five), sulphur‐containing compounds (two to three) and pyrazines (zero to four) which were the main components. The percentage content of aldehydes and ketones reduced over time as the temperature rose with each stage of the process, whereas alcohols, carboxylic acids, esters, pyrazines and sulphur‐containing compounds increased gradually. Jinhua ham's high‐temperature maturating process (40 days at 30–37 °C) made the percentage content of carboxylic acids arising from Maillard reactions markedly increase (from sun‐dried ham 8.45% to fully aged ham 19.23%). This was the most obvious difference between Jinhua ham and the Mediterranean dry‐cured hams, and was the main factor leading to the unique flavour of Jinhua ham.     

Changes of alanyl aminopeptidase activity and free amino acid contents in biceps femoris during processing of Jinhua ham

Sixty experimental Jinhua hams were processed by a traditional method. The potential alanyl aminopeptidase (AAP) activity in biceps femoris was determined. The effects of temperature, salt content, sodium nitrate content and pH on muscle AAP were evaluated using response surface methodology. Porcine muscle was found to possess very strong potential AAP activity that decreased gradually during processing from 201,635 U g⁻¹ before salting to 6147 U g⁻¹ after aging. Temperature, pH and salt content had significant exponential effects on AAP activity (P < 0.001). Both temperature and salt content interacted with pH in their effects on AAP activity (P < 0.01). However, 0–50 mg L⁻¹ sodium nitrate had no detectable effect on AAP activity (P > 0.05). The regression model showed muscle AAP maintaining its activity all through Jinhua ham processing, indicating that muscle AAP may generate free amino acids during the processing and storage of Jinhua ham. The concentrations of free amino acids increased significantly (P < 0.05) during Jinhua ham processing, except for arginine and cystine. The concentrations of most free amino acids were 5–20 times higher in the final product than in hams before salting. Final concentrations exceeded thresholds for sensory detection, thus implicating an important role of free amino acids in the determination of Jinhua ham flavor.