Changes of proximate composition and extractive components in narezushi, a fermented mackerel product, during processing

ABSTRACT:   During the processing of mackerel narezushi , the fish body was strongly dehydrated by permeation of salt, the low pH of fish meat, and pressure applied to the fish and rice mixture. In the proximate components, moisture, protein and lipid flowed out from the fish meat into the rice mixture, and sugar permeated from the rice mixture into the fish meat. That the total amount of outflow was larger than that of permeation into the fish is thought to contribute to the decrease in fish body weight during processing. In the extractive components, although the nucleotides completely decomposed, free amino acids and peptides increased remarkably because of the decomposition of proteins in fish meat during processing. Especially, six kinds of free amino acid, Glu, Asp, Gly, Ala, Leu, and Ile, which are thought to be the taste components in marine resources, increased. Organic acid increased remarkably because of the fermentation of rice and permeation into the fish meat. The marked increase of the extractive components is thought to contribute to the umami taste and the sour taste of narezushi .     

Comparison of taste components in cooked meats of small abalone fed different diets

ABSTRACT: Differences in taste preference and the levels of extractive components and glycogen were compared between cooked meats of small abalone Haliotis diversicolor fed either gracilar (G-small abalone) or an artificial diet (A-small abalone). Using sensory tests, taste preference of cooked meats was significantly higher for A-small abalone than for G-small abalone. Results of clustering analysis and principal component analysis of chemical data also revealed that the two cooked meats differed from each other in terms of their measured constituent compositions irrespective of sampling periods. Compared with G-small abalone, A-small abalone meats were lower in taurine and arginine, but higher in glycine (Gly), glutamic acid (Glu), alanine, serine, proline, adenosine monophosphate (AMP), and glycogen. It is concluded that the discrepancy in the levels of taste-active components of abalone, such as Gly, Glu, and AMP, is likely to be responsible for the differences in taste preference between G- and A-small abalone cooked meats.     

野生巨(鱼丕)肌肉营养成分测定和分析

对野生巨(鱼丕)(Bagarius yarrelli Sykes)肌肉的营养成分进行测定和分析。结果显示:巨(鱼丕)是一种较少见的具有黄色肌肉的鱼类。巨(鱼丕)含肉率为48.78%、肌肉中水分含量77.28%、粗蛋白含量18.01%、粗脂肪含量2.52%、灰分含量2.19%;肌肉中水解氨基酸总量为14.15%,含量最高为缬氨酸(1.35%),最低为甘氨酸(0.45%);必需氨基酸含量为6.21%,占氨基酸总量的43.89%,氨基酸价为160.81,第一和第二限制氨基酸是亮氨酸和赖氨酸(1973年FAO/WHO标准)。结果表明巨(鱼丕)是一种营养价值较高有待开发的野生鱼类。     

云南裂腹鱼肌肉生化成分分析与营养品质评价

对采自洱海上游弥苴河的云南裂腹鱼Schizothorax yunnanensis肌肉营养组成进行分析与评价.结果表明,云南裂腹鱼肌肉蛋白质含量16.86%,脂肪含量1.15%;饱和脂肪酸含量27.92%,单不饱和脂肪酸含量42.44%,多不饱和脂肪酸含量15.35%,必需脂肪酸含量41.50%,二十碳五烯酸(C20:5)与二十二碳六烯酸(C22:6)总含量1.67%;氨基酸总量78.50 mg·100 mg-1,必需氨基酸总量36.86 mg·100 mg-1,呈味氨基酸总量27.95 mg·100 mg-1,赖氨酸(Lys)含量仅次于谷氨酸(Glu),高达8.66 mg·100 mg-1,必需氨基酸中蛋氨酸(Met)+胱氨酸(Cys)的氨基酸分和化学分最低,分别为89和66,为云南裂腹鱼肌肉中的限制性氨基酸.     

舌虾虎鱼肌肉营养成分与品质的评价

对舌虾虎鱼的肌肉营养成分进行了分析,并对其营养品质进行了评价。结果表明,舌虾虎鱼肌肉(鲜样)中水分、粗蛋白、粗脂肪和粗灰分的质量分数分别为79.92%±0.96%、16.76%±0.30%、0.91%±0.07%和2.25%±0.14%。肌肉中含有18种氨基酸,总量为78.70%±0.57%(质量分数,干样),其中8种必需氨基酸(EAA)总量是32.26%±0.55%,占氨基酸总量的40.99%,其必需氨基酸的构成比例符合联合国粮农组织/世界卫生组织(FAO/WHO)的标准。舌虾虎鱼的第一限制性氨基酸为色氨酸,第二限制性氨基酸为(蛋氨酸+胱氨酸),必需氨基酸指数(EAAI)为63.88,4种鲜味氨基酸(DAA)总量为29.67%±0.30%(质量分数,干样)。脂肪酸中EPA与DHA质量分数分别为3.91%±0.11%和8.10%±0.60%,明显高于其它几种淡水经济鱼类。研究表明,舌虾虎鱼含有丰富的氨基酸和脂肪酸营养,具有较好的食用价值与保健作用。     

Responses to prolonged hypoxia by rainbow trout (Salmo gairdneri) I. Free amino acids and proteins in plasma,liver and white muscle

In order to estimate the mobilization of nitrogen compounds for energetic purposes in trout under hypoxic conditions, commercial-size rainbow trout, acclimated to 15°C, were maintained for 10 weeks at an oxygen level of 5.3 ± 0.5 mg/l (hypoxic group) or 8.4 ± 0.4 mg/I (control group), and the changes in tissue concentrations of free amino acids and proteins studied. In animals subjected to hypoxia, there was a decrease in plasma free amino acids involved in gluconeogenesis, liver alanine and aspartic acid, plasma and liver protein concentrations, and muscle free histidine. These results suggest a trend of rainbow trout metabolic activity towards energy production at the expense of anabolism when oxygen availability in water is limited over a long period of time.     

池塘低盐养殖点篮子鱼肌肉营养成分的分析与评价

点篮子鱼(Siganus guttatus)在低盐池塘中养殖102 d后,对其营养成分及其品质进行了分析和评价。结果表明,点篮子鱼新鲜肌肉中水分、粗灰分、粗蛋白和粗脂肪的质量分数分别为(75.17±0.87)%、(0.60±0.08)%、(22.33±0.50)%和(1.96±0.13)%;其肌肉干样中共检出19种氨基酸,总量为(89.03±0.36)%,其中,必需氨基酸总量为(34.26±0.12)%,占总氨基酸含量的38.49%,半必需氨基酸总量为(7.39±0.10)%,非必需氨基酸总量为(46.50±0.48)%,必需氨基酸与非必需氨基酸的比值为73.68%。可见,低盐度养殖点篮子鱼的必需氨基酸构成比例符合联合国粮农组织/世界卫生组织(FAO/WHO)的标准。根据氨基酸品质评价,其第一限制性氨基酸为色氨酸,第二限制性氨基酸为缬氨酸,必需氨基酸指数为75.44。低盐度养殖的点篮子鱼肌肉干样中鲜味氨基酸总量为(33.97±0.32)%,占总氨基酸含量的38.15%。综合来看,低盐度养殖的点篮子鱼必需氨基酸营养组成合理,鲜味氨基酸含量丰富,是一种营养丰富、味道鲜美的理想养殖对象。     

饥饿对斜带石斑鱼肝脏和肌肉脂肪酸组成的影响

在室外水泥池(4m×1.5m×1m)进行石斑鱼(62.3±0.6g)的饥饿实验,每池放养35尾,设3个重复,实验时间分别为0、1、2、3和4周。随着饥饿时间的延长,体重减轻,肥满度和肝体比显著降低;肌肉水分显著增加而蛋白质含量显著下降(P<0.05),脂肪含量在第1周下降后基本保持稳定。肝脏饱和脂肪酸在饥饿前3周基本保持不变,第4周显著下降。单不饱和脂肪酸在饥饿第1周保持不变,然后呈下降趋势。多不饱和脂肪酸和高不饱和脂肪酸的总和随着饥饿时间的延长,含量显著增加。与肝脏相比,肌肉中脂肪酸变化程度较小。随着饥饿时间的延长,肌肉中140减少而205增加。饥饿使肌肉中DHA/EPA比率呈下降趋势,但肝脏DHA/EPA比率显著上升;肌肉和肝脏中DHA EPA的百分比都随饥饿时间的延长而显著上升。     

Comparison in taste and extractive components of boiled dorsal muscle and broth from half-smooth golden puffer Lagocephalus spadiceus caught in Japan with those of the same fish imported

The taste and extractive components of boiled dorsal muscle and broth prepared from half-smooth golden puffer Lagocephalus spadiceus caught in Japan and from those imported from China were compared. In the sensory test, the first taste, elasticity, and saltiness of boiled muscle from Japanese (domestic) fish were higher than those of the imported fish, whereas the orthonasal fishy smell of the imported fish was higher than that of the domestic fish. The first taste, aftertaste, retronasal fishy smell, sweetness, saltiness, and umami of the broth prepared from dorsal muscle of the domestic fish were higher than those of the imported fish, whereas orthonasal fishy smell and bitterness of the imported fish were higher than those of the domestic fish. Most panelists preferred the overall taste of the domestic fish to that of the imported fish. The concentration of trimethylamine in the trichloroacetic acid extracts from boiled muscle and broth of the imported fish was higher than that of the domestic fish, suggesting that this substance contributes to the orthonasal fishy smell of the imported fish.     

Changes in some components of the muscle lipids of three freshwater fish species under natural extreme cold and temperate conditions

Fatty acid composition, conjugated linoleic acid and cholesterol contents in the muscles of three freshwater fish species (Barbus plebejus escherichi, Capoeta capoeta capoeta and Rutilus rutilus) were determined under natural extreme temperate (July) and cold (January) conditions. The aim of the study was to determine whether there were differences in these components of the muscle lipids among these three fish species under extreme natural conditions. Samples were analyzed using gas chromatography. Palmitic, oleic, docosahexaenoic and eicosapentaenoic acids were the predominant fatty acids in all fish in both months. The percentages of polyunsaturated fatty acids, n − 3 polyunsaturated fatty acids, n − 6 polyunsaturated fatty acids and eicosapentaenoic + docosahexaenoic acids in the muscle of B. plebejus escherichi and C. capoeta capoeta were significantly higher in January (P < 0.05) than in July. The ratio of n − 6 to n − 3 polyunsaturated fatty acids was lower than 0.60 in all fish species, with C. capoeta capoeta showing the lowest ratio in January (0.36). The levels of cholesterol and conjugated linoleic acid ranged from 103.46 to 150.10 mg/100 g oil and from 16.27 to 35.45 mg/100 g oil, respectively, for all samples in both months. There were no statistical differences in cholesterol levels among the three fish species in July and January. Conjugated linoleic acid contents were significantly higher in January in B. plebejus escherichi and C. capoeta capoeta. Of the three species tested, the extreme temperate and cold conditions affected B. plebejus escherichi the most.     

两种不同营养类型水库鲢、鳙肌肉营养成分的比较

实验采用国标(GB)的检测方法,依据联合国粮农组织(FAO)和世界卫生组织(WHO)的评价标准,对不同营养类型的金沙河水库和桃园河水库的鲢、鳙肌肉营养成分进行了分析比较。结果表明,金沙河水库鲢、鳙的粗蛋白(P<0.05)含量显著高于桃园河水库,金沙河水库鳙的粗脂肪含量显著高于桃园河水库(P<0.05)。两座水库鲢、鳙的氨基酸种类组成相同,但金沙河水库鲢的氨基酸总量和鲜味氨基酸含量显著高于桃园河水库(P<0.05),而其余氨基酸含量的差异不显著。金沙河水库鲢、鳙的必需氨基酸指数(EAAI)均大于桃园河水库。综合这些指标,认为金沙河水库鲢、鳙鱼肌肉品质高于桃园河水库。