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1.
ABSTRACT:   The effect of storage temperature (0, 5, 10, and 15°C) and killing procedure (instant, struggled, temperature shocked, and spinal cord destruction killing) on post-mortem changes in the muscle of the horse mackerel caught near Nagasaki, Japan, was investigated. Temporal changes in adenosine triphosphate (ATP), inosine monophosphate (IMP), and lactic acid concentrations were slowest at 10°C storage temperature. The increase in K -values was slower at 10°C and below than at 15°C storage temperature. In addition, 10°C storage temperature was most suitable for maintaining a constant breaking strength value of the muscle. Regarding the effect of killing procedure, temporal changes in ATP, IMP, and lactic acid concentrations were slowest when killed by spinal cord destruction. The increase in K -value and the decrease in breaking strength were also slowest in the spinal cord destruction group. From these results, it was considered that storage at 10°C temperature and spinal cord destruction killing procedure were most effective in delaying post-mortem change in the horse mackerel.  相似文献   

2.
To characterize post-mortem changes in fish meat quality during chilled and frozen storage, muscle toughness and the connective tissue structure of muscle were compared between two mackerel species, spotted mackerel Scomber australasicus and Pacific mackerel S. japonicus. Measurement of the breaking strength of meat slices from both non-frozen fresh fish and frozen-thawed fish revealed that spotted mackerel meat was softer than Pacific mackerel meat. Under scanning electron microscopic observation, the connective tissue of non-frozen meat of spotted mackerel was thinner than that of Pacific mackerel. In addition, the collagen content in the spotted mackerel meat was lower than that of Pacific mackerel. These findings suggest that connective tissue structure might influence muscle toughness in mackerel.  相似文献   

3.
ABSTRACT:   Using the skeletal muscle of full-cycle cultured Pacific bluefin tuna (body weight: 13.1 ± 2.6 kg, cultured for about 21 months), the proximate compositions, breaking strength and histological structure of the front and rear parts of the dorsal ordinary muscles (FD-OM and RD-OM) and the ventral ordinary muscles (FV-OM and RV-OM) were compared. The FV-OM showed low moisture, protein, ash and high fat contents ( P  < 0.05, respectively) for the other three positions. The breaking strength of FD-OM, RD-OM and RV-OM increased up to 15–18 h and decreased later. However, the breaking strength of FV-OM was maintained during chilled storage. The pH of all muscles decreased up to 15 h, and then stayed at pH 5.7–5.8. However, the pH of FV-OM stayed at a higher level (pH 5.9). The histological structure observed by optical microscopy showed a space extension among muscle cells after 24 h in all positions, and these results were also supported by image analysis.  相似文献   

4.
Members of the myxosporean genus Kudoa occur in various marine teleosts worldwide. Several species are of concern to the fishery and aquaculture industries as they may produce unsightly cysts in the fish host's musculature or are associated with postmortem myoliquefaction of the fish muscle, commonly referred to as 'soft flesh'. This study describes the occurrence and effects on a host of a Kudoa species in Atlantic mackerel, Scomber scombrus , from the northern North Sea. Generalized postmortem myoliquefaction associated with Kudoa sp. occurred in 0.8% of the examined fish, i.e. 11 of 1339 mackerel developed 'soft flesh'. There was a significant difference in the prevalence of myoliquefaction between medium sized (400–600 g) and large mackerel (>600 g). The prevalence reached 8.9% in the latter host size group. No subclinical infections of Kudoa sp. were detected when examining fresh muscle ( n  = 103) and blood ( n  = 165) samples for spores using light microscopy. Affected mackerel developed generalized myoliquefaction after 38–56 h post-catch. No inflammatory host response was associated with the presence of plasmodia within single body muscle fibres of 'soft flesh' affected fish. Based on comparison of myxospore dimensions and analysis of the nuclear small subunit (SSU) ribosomal DNA, the present Kudoa species is assigned to Kudoa thyrsites . However, due to the species' apparently very wide geographical distribution and host range, its varying effect on different fish host species, together with the still unknown life cycle of Kudoa spp., the taxonomic status of K. thyrsites appears not to be fully resolved.  相似文献   

5.
The study was conducted to evaluate the meat texture, muscle proximate composition, lipid class composition, and collagen content of cultured amberjack and to compare these parameters with those of the yellowtail. Our results showed that the meat texture of cultured amberjack was tougher and had a lower degree of seasonality than that of cultured yellowtail. Muscle lipid and collagen content also varied in the two fish species over the study period. Meat breaking strength was not correlated with any of the muscle constituents, indicating that variations in the meat texture of cultured amberjack was not directly influenced by the changes in the muscle biochemical constituents.  相似文献   

6.
乙纶经编网片断裂强力特性研究   总被引:1,自引:0,他引:1  
本研究以国家有关测试标准为依据,采用裂区模型实验设计方法对多种系列乙纶单丝经编网片测样进行测定,数据采用多元方差分析方法,分析了网片纵横向之间、干湿态之间的断裂强力和断裂伸长率的差异性,找出了影响网片断裂强力和断裂伸长率的主要因素,分析了各主要因素影响的程度和趋势,回归各因素与断裂强力和断裂伸长率间的关系。研究分析结果表明,乙纶经编网片的断裂强力和断裂伸长率均与目脚总丝数、编织密度和成圈丝数有高度显著的线性关系。  相似文献   

7.
ABSTRACT:   Changes in meat firmness and structure of cultured yellowtail at several storage temperatures, from −1.5°C to 10°C, were compared. Firmness decreased less at −1.5°C and 10°C than at the other temperatures. During storage at temperatures from −0.5 to 4.0°C, expansion of intercellular space, which indicates weakening of the connecting force between muscle cells, began to increase after 8 h storage, and the ratio of space to the whole area increased by 3.4–4.9 times after 24 h of storage. However, at −1.5°C and 10°C, the increase of intercellular space was suppressed, and the ratio was 2.4–2.6 times, even after 24 h storage. Collagen fibrils connecting muscle cells disintegrated after 24 h storage at all storage temperatures. Conversely, in 10°C storage, the fine structure of muscle, except for collagen fibrils, was maintained better than at other storage temperatures. These findings indicate that −1.5 and 10°C storage could maintain fish-meat quality for longer periods than storage at −0.5, 1.0, or 4.0°C, the normal refrigeration temperature.  相似文献   

8.
SUMMARY: In a study of the relationship between structural changes and rheological parameters of raw and cooked abalone meat, abalone Haliotis discus was cooked in boiling water for 3 h, then cut up and separated into cross- and vertical sections. Structural change was observed using a light microscope and scanning electron micrography. The rheological parameters were obtained by stress-relaxation experiments. Microscopic photography revealed that structural change between muscle fibers in both sections of the cooked meat was greater than that in the raw meat. The elastic modulus and rupture strength in both sections of cooked meat showed no difference between the cross- and vertical sections, and were smaller than those for the raw meat. The relaxation time for the cooked meat was also greater than for the raw meat. These results were mainly because of collagen being gelatinized during heating. These changes were also observed by staining collagen and differential scanning calorimetry.  相似文献   

9.
ABSTRACT:   The present study was undertaken to assess the lipid composition and deposition in muscle at three anatomical locations in cultured yellowtail and to investigate the effect of lipid composition and deposition on meat texture. Lipid deposition in muscle was studied by histochemical staining of lipid with Sudan dye. Lipid class composition analysis showed that neutral lipids were the main constituents of lipid in cultured yellowtail and accounted primarily for the variation in muscle lipid content with the anatomical location of meat, as well as with season, whereas the polar lipid content remained almost constant. Furthermore, muscle neutral lipid content was correlated negatively with meat breaking strength; however, no correlation was observed between muscle polar lipid content and meat breaking strength. The histochemical study revealed that, in yellowtail muscle, lipid is preferentially deposited in the myosepta and, with increases in muscle lipid content, additional fat is deposited along sparsely distributed thin connective tissue. It was also observed that the greater the lipid deposition in collageneous connective tissue, the lower the meat breaking strength; presumably, higher lipid deposition in the connective tissue resulted in weakening of the muscle structure.  相似文献   

10.
The effects of fasting on the quality of the dorsal and ventral ordinary muscles from cultured Pacific bluefin tuna (Thunnus orientalis) during chilled storage were investigated. Tuna were subjected to fasting for 2 days in the summer or 6 days in the winter prior to harvesting. The breaking strength of the dorsal ordinary muscle sampled in the summer increased until 24 h and then decreased. There were no significant differences in the lipid and glycogen content of the ordinary muscle after 9 h of storage between the controls and either fasting group. The pH of the ordinary muscle subjected to summer and winter fasting was higher than in the controls after 24–48 h of storage. However, the relationship between the pH and glycogen content was unclear. The metmyoglobin content during chilled storage was lower in the ordinary muscles from either fasting group than in the controls. In conclusion, fasting for 6 days in the winter improved the color stability of the ordinary muscle without a decline in its lipid content.  相似文献   

11.
机织单死结锦纶网片不同定型方向的断裂强力比较   总被引:1,自引:0,他引:1  
本研究以国家有关测试标准为依据,采用裂区模型实验设计方法,对多种系列机织单死结锦纶网片试样进行测定,数据采用多元方差分析方法,分析了网片纵横向之 断裂强力和断裂伸长率的差异性,找出了影响网片断裂强力和断裂伸长率的主要因素,分析了各主要因素影响的程度和趋势。研究结果表明,机织单死结网片采用横向定型时,其断裂强力和断裂伸长率均大于采用纵向定型。  相似文献   

12.
The season for finding the firmest sashimi made from wild Japanese sea bass was investigated. Flesh rigor tension and contraction were measured by a “new” device with isometric (muscle length kept constant) and isotonic (balance beam moves freely) transducers. Both flesh rigor tension and contraction peaks appeared at the same postmortem times, with attainment of ultimate pH and adenosine triphosphate/inosine monophosphate ratio in four seasons. Seasonal seawater temperature correlated negatively to seasonal maximum rigor contraction and positively to seasonal flesh breaking strength at 72 h postmortem. After rigor peak tension attainment, the tension relaxation was much lower than that of other wild fish species, especially in summer. The sea bass muscle resisted structure disruption in rigor isometric tension generation. Wild sea bass sashimi was firmest in breaking strength in summer.  相似文献   

13.
14.
In the present study, we assessed small fishes as potential feed fishes with the lowest mercury levels. The mercury levels of four small pelagic fishes and a benthic fish from the Pacific Ocean and the Sea of Japan, i.e., spotted chub mackerel Scomber australasicus, chub mackerel Scomber japonicus, horse mackerel Trachurus trachurus, round scad Decapterus punctatus, and bastard halibut Paralichthys olivaceus, were determined. Total mercury levels in fish muscle were measured using a reduction vaporizing atomic absorption method. There were no significant correlations between body weight and mercury levels for these species. However, significant differences were observed in the mercury levels of these species between the two catch locations, with fish caught in the Pacific Ocean having higher mercury levels. This difference may be due to the Pacific Ring of Fire, a highly seismically and volcanically active zone, which is located in the Pacific Ocean. Preference for these fishes for use in aquaculture should refer to the area where they are caught in addition to the species.  相似文献   

15.
为给渔用材料的合理选用提供参考,以三元共混网线材料(中高分子量聚乙烯/聚丙烯/三元乙丙橡胶,MHMWPE/PP/EPDM)作为研究对象,按不同混合比、不同直径进行网线的断裂强力及结节强力试验,分析其相应的强力、延伸性等性能。结果显示,三元共混网线材料的断裂强力随着直径增大而增加,优于同等直径普通聚乙烯网线材料,且随着直径增大,差异性越明显,最大差异时三元共混网线材料的断裂强力为2 091.4 N,是普通聚乙烯的1.8倍;在相同的网线直径条件下,三元共混网线材料断裂强力均随PP含量增加而增加;在相同的直径下,三元共混网线材料的断裂伸长率小于普通聚乙烯网线材料,结节损失率高于普通聚乙烯网线材料。三元共混网线材料,虽然断裂伸长率低、结节损失率高,但强力性能要优于普通聚乙烯,可在渔业生产中推广应用。  相似文献   

16.
The spawning grounds of the chub mackerel (Scomber japonicus) and spotted mackerel (Scomber australasicus) in the East China Sea were estimated based on catch statistics of the Japanese large- and medium-type purse seine fishery from 1992 to 2006. Biometric data were obtained from specimens caught by purse seiners in the East China Sea from 1998 to 2006. Gonadosomatic index (GSI) at 50% sexual maturity of chub mackerel and spotted mackerel females was 2.5 and 2.6, respectively. Using this criterion for GSI, chub mackerel larger than 275 mm and spotted mackerel larger than 310 mm in fork length were considered to be mature. Mature chub mackerel was observed in the area of 15–22°C sea surface temperature (SST), and mature spotted mackerel was observed in the area of 17–25°C SST. The spawning period of chub mackerel ranged from February to June, and that of spotted mackerel ranged from February to May in the East China Sea. The spawning grounds were estimated from the distributions of catch per unit effort (CPUE) of spawners and SST. As a result, the spawning ground of chub mackerel was estimated to be in the central and southern part of the East China Sea and the area west of Kyushu in February, March, and April, and in the central part of the East China Sea, the area west of Kyushu and Tsushima Straight in May, and in Tsushima Straight and western part of the Sea of Japan in June. The spawning ground of spotted mackerel was estimated to be in the central and southern part of the East China Sea and southern coastal area of Kyushu in February, March, and April, and the central and southern part of the East China Sea and the area west of Kyushu in May.  相似文献   

17.
桑叶黄酮对吉富罗非鱼肌肉抗氧化指标及营养组成的影响   总被引:2,自引:0,他引:2  
为研究饲料中添加桑叶黄酮对吉富罗非鱼(Oreochromis niloticus)肌肉抗氧化指标及营养组成的影响,选取初始体重为(1.51±0.02)g的吉富罗非鱼840尾,随机分为6组,每组4个重复,每个重复35尾鱼,在56 d饲养期中分别投喂添加桑叶黄酮0、50、100、300、500和1 000 mg/kg的试验饲料。结果显示:100、300 mg/kg组肌肉超氧化物歧化酶(SOD)活性显著高于其他各组,且分别比对照组提高了6.2%和8.7%;500 mg/kg组肌肉总抗氧化力(T-AOC)显著高于1 000 mg/kg组及对照组;50、100、300、1 000 mg/kg组肌肉丙二醛(MDA)含量显著低于对照组。饲料中添加桑叶黄酮对吉富罗非鱼肌肉粗蛋白、粗脂肪、灰分和水分含量没有显著影响,对肌肉滴水损失影响不显著。500 mg/kg组胶原蛋白含量显著高于对照组,与其他组差异不显著。50 mg/kg组肌肉苯丙氨酸含量与对照组相比显著升高。100 mg/kg组肌肉丙氨酸含量显著高于对照组和50、300、500 mg/kg组。300 mg/kg组肌肉亮氨酸、蛋氨酸和谷氨酸和1 000 mg/kg组肌肉组氨酸含量显著高于对照组。结果表明,添加适量的桑叶黄酮可以显著提高吉富罗非鱼肌肉抗氧化指标和胶原蛋白含量,改善肌肉氨基酸组成。综合肌肉抗氧化性能、胶原蛋白含量和氨基酸组成的指标来评价,桑叶黄酮添加水平在300~500 mg/kg时效果较好。  相似文献   

18.
以网片断裂强力、网片断裂伸长率和网片断裂强力保持率为指标,研究了不同K型网目对渔用乙纶网片拉伸力学性能的影响。结果表明:K型网目下网目内径之比在1.01~1.20时,网片断裂强力随着网目内径之比的增大而下降,两者呈密函数相关。同规格线的网片,K型网目下且两网目内径之比相同时,小规格网目尺寸的网片断裂强力损失小,断裂伸长率高,而大规格网目尺寸的网片断裂强力损失大.断裂伸长率低。  相似文献   

19.
为探究传统水产加工制品咸干鲅鱼(Scomberomorus niphonius)的风味形成规律,对咸干鲅鱼自然风干不同阶段的水分含量、肌肉硬度值、游离氨基酸、呈味核苷酸以及挥发性成分进行了测定.结果表明,鲅鱼自然风干过程中水分含量逐渐减少,肌肉硬度值增大,逐渐形成肉质柔韧、富有嚼劲的特有口感.游离氨基酸总量在风干前期显...  相似文献   

20.
ABSTRACT:   This study examined the thermal gelation characteristics of myofibrillar protein (MP) and salt-ground horse mackerel surimi that had been mixed with hydroxypropylmethylcellulose (HPMC). Analysis, using thermal scanning rigidity monitor and differential scanning calorimetry, demonstrated that thermal gelation begins in the thermo-reversible HPMC gel used in this study at approximately 60°C. In the rescanning test, first scanning diagrams showed similar pattern, but second scanning diagrams were rather diverse between MP and MP/HPMC mixture. The addition of HPMC increased rigidity of salt-ground surimi and modified the thermal gelation during the heating process, suggesting that certain enhancing effect of gelation occurred when the mixture of MP and HPMC was heated. In the annealing test, the addition of HPMC lowered the breaking force, but increased the gel strength of surimi due to a substantial increase in deformation. Although the strong cross-linking between the two components might not occur during the gelling process, HPMC gel formed at high temperature occupies some space in thermal gel by interacting with proteins and resulted in a combinative gel with a higher rigidity and gel strength at higher temperature.  相似文献   

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