【作者】 杨倩倩；

【导师】 余以刚； 李志勇；

【作者基本信息】 华南理工大学 ， 食品工程， 2011， 硕士

【摘要】 大黄鱼(Pseudosciaena crocea),属石首鱼科,其肉质细嫩鲜美、蛋白质高、固醇低,具有治疗贫血、滋补身体的功能而成为海水鱼类中的极品,深受海内外消费者的青睐。近年来由于过度捕捞,导致大黄鱼资源急剧衰退。为此,我国科技工作者就大黄鱼人工繁殖及育鱼技术进行了长期的研究,使人工养殖大黄鱼技术不断成熟,大黄鱼的产量上升很快,现产区主要集中在浙江沿海和福建闽东地区。本课题针对目前养殖大黄鱼脂肪含量高,腥味大的缺陷,对其进行脱脂、脱腥技术研究,以降低养殖大黄鱼的脂肪,减少鱼体腥味,从而改善养殖大黄鱼的肉质口感和品质。主要分析了利用碳酸钠、碳酸氢钠法和酶法对大黄鱼进行脱脂的工艺,通过复合盐法进行脱腥处理,以及脱腥前、后养殖大黄鱼中挥发性成分的组成变化,感官评价和质构的变化,为养殖大黄鱼脱腥生产工艺的优化提供理论依据。养殖大黄鱼的脂肪含量较高,湿基为15.6%,干基达到56.1%,远超过野生大黄鱼的含量。Na2CO3脱脂的最佳工艺条件为浓度6g/100mL,浸泡时间90min,鱼水比1:2,脱脂率达到41.18%;NaHCO3脱脂的最佳工艺条件为浓度0.5g/100mL,浸泡时间60min,鱼水比1:2,脱脂率达到45.69%;碱式脂肪酶脱脂的最佳工艺条件为浓度40U/mL,pH值为8.0,浸泡时间为30min,鱼水比1:3,脱脂率达到44.89%。综合考虑脱脂率及生产条件,采用0.5g/100mL NaHCO3脱脂的大黄鱼蛋白质损失率较低,脱脂效果最好。将0.5g/100mL的NaHCO3和10g/100mL的NaCl结合作为养殖大黄鱼的混合脱腥液,通过感官评价,腥味随着盐浓度的升高而逐渐减弱,经处理后的大黄鱼鱼腥味、金属味、泥土味、蘑菇味以及不愉快的脂肪气味已基本去除。可见,NaCl在脱腥处理中起到协同增效的作用,不仅有效地降低养殖大黄鱼的脂肪,还能促进鱼体内腥味成分的析出,从而改善养殖大黄鱼的肉质、风味等品质。通过对萃取头的选择,萃取时间、萃取温度和解吸时间等条件的优化,可知养殖大黄鱼挥发性成分固相微萃取的最佳条件为:萃取头选用CAR/PDMS、萃取时间30min、萃取温度60℃、解吸时间5min。脱脂脱腥前的大黄鱼检测出48种成分,其中以羰基化合物和醇类为主,处理后的大黄鱼检测出19种成分,腥味成分主要为己醛、2,4-癸二烯醛、1-戊烯-3-酮、3,5-辛二烯-2-酮、1-戊烯-3-醇和1-辛烯-3-醇。经碳酸氢钠法处理和复合盐法处理后养殖大黄鱼在挥发性成分的含量上有较明显的差别,腥味成分和起协同作用的物质含量大大减少。这些醇类、酮类和醛类化合物所表现出来的鱼腥味、金属味、泥土味、蘑菇味以及不愉快的脂肪气味已基本去除,不良气味明显降低。经GC-MS测定养殖大黄鱼中挥发性成分的变化所引起的气味的改变与感官评价的结果一致。由此可见,复合盐法是一种有效的脱脂脱腥处理方法。使用质构仪进行TPA模式的质构分析,从硬度、黏性、弹性、黏聚性、胶着性、咀嚼性和恢复性等参数的变化可以看出,脱脂脱腥后各项质构指标变化不大,不影响大黄鱼整体的品质。更多还原

【Abstract】 Pseudosciaena crocea is a kind of drum fish. The meat of Pseudosciaena crocea is delicate and delicious, which has high protein content and low cholesterol content. It is also good for treating anemic and body health. Thus Pseudosciaena crocea becomes one of the best edible fish in marine fish, which is deeply liked by many consumers around the world. But in recent few years, due to arbitrarily catching, Pseudosciaena crocea resources declined severely. To protect the resource of Pseudosciaena crocea, the aquatic scientists have researched for many years. The yield of farmed Pseudosciaena crocea has increased continuously, in Zhejiang and Fujian mindong coastal area.In order to lower the fat content, reduce the fishy smell, and improve the fish meat quality of the farmed Pseudosciaena crocea, this study aims at the problems of high fat content and strong fishy smell of farmed Pseudosciaena crocea and research the degreasing and deodorizing technology. The study mainly analysis the process of degreasing technology by Na2CO3 and NaHCO3 and enzyme for Pseudosciaena crocea, and the change of volatile organic compounds and structure through handling deodorization combined with NaHCO3 and NaCl, sensory evaluation, to provide the theory basis for making a performance optimization in deodorization.Pseudosciaena crocea contains a lot of fat, and wet basis is 15.6%, while dry basis reached 56.1%, which is far more than the wild Pseudosciaena crocea content. The best degreasing method of Na2CO3 is liquid concentration of 6g/100mL, marinating time of 90min, fish and water marinating proportion of 1:2, skim rate of 41.18%; the best degreasing method of NaHCO3 is liquid concentration of 0.5g/100mL, marinating time of 60min, fish and water marinating proportion of 1:2, skim rate of 45.69%;The best degreasing method of enzyme is concentration of 40U/mL, pH8.0, marinating time of 30min, fish and water marinating proportion of 1:3, skim rate of 44.89%. Considering skim rate and production conditions, the best degreasing method is using NaHCO3.The combination of 0.5g/100mL NaHCO3 and 10g/100mL NaCl were used as the mixing deodorization liquid to breed Pseudosciaena crocea. Sensory evaluation showed that the fishy smell weared off as the concentration of salt increased. After processing, the fishy smell, metallic taste, earthy taste, mushroom taste and unpleasant fat smell of Pseudosciaena crocea had basically been removed. It is clear that NaCl played a synergistic role in the process and improved the meat quality and flavor of Pseudosciaena crocea. It not only reduced the fat effectively, but also promoted precipitation of the composition of fishy smell.As a result of choosing fiber, time, temperature and desorption time, we can know the best condition for culturing Pseudosciaena crocea on SPME fibers is extracting in 60℃and 30min, desorbing in 5 minutes by CAR/PMS. There are 48 compositions detected, of which the main component are carbonyl compound and alcohol. The processed yellow fish contains 19 components. Raw taste has been mainly caused by 2,4-Decedienal, hexaldehyde, 1-Penten-3-one, 3,5-Octadien-2-one, 1-Penten-3-ol, and 1-Octene-3-ol.There are obviously differences between Pseudosciaena crocea treated by NaHCO3 process and mixet salt combination treatment. The composition of fishy smell and substance which played the synergy role was greatly reduced. The fishy smell, metallic taste, earthy taste, mushroom taste and unpleasant fat smell of Pseudosciaena crocea contributed by alcohols, ketone and aldehyde compounds had basically been removed. GC-MS results showed that the changes of smell caused by the changes of volatile components in cultured Pseudosciaena crocea were consistent with the sensual evaluation results. It showed that mixet salt combination is a kind of effective skim deodorization processing method.Through the analysis of quality and structure of Pseudosciaena crocea by instrument TPA mode, from hardness, adhesiveness, springiness, cohesiveness, gumminess, chewiness, resilience, the parameters result show that degreasing and deodorizing do not affect the character of Pseudosciaena crocea.更多还原