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1.
An “abnormal” female Scylla paramamosain, named “Butter crab” (B_♀) is more popular than wild‐type mud crab (CK) with people. Histologically, “butter crab” ovaries are partially degraded, with full of yellow oily substances in body. Composition of the essential nutritional components is quite similar in “butter crab” and CK. In a comparison of fatty acids, B_♀ is richer. A comparison of flavour amino acids and nucleotide in muscle showed that sweet amino acids and bitter amino acids in B_♀ is lower than CK_♀, but umami amino acids are significantly higher in B_♀. However, the umami amino acid content in the gonads is significantly less in B_♀ than CK_♀. Moreover, umami nucleotides in B_♀ muscle is significantly higher. From the perspective of EUC evaluation, the umami taste of CK_ ♀ gonads is strongest, followed by B_ ♀ gonads. In the hepatopancreas, the umami taste ranks CK_♀> B_♀ >CK_♂, and there are no significant differences among muscles in the three groups. In conclusion, the characteristics of “butter crab” are more fragrant and nutritious, with sweet and umami taste. The article systematically scientifically analysed the nutritional composition and flavour characteristics of “butter crab”, providing a novel insight for development of S. paramamosain industry.  相似文献   

2.
Overwintering is an important part of the conservation of Scylla paramamosain, and salinity has an important effect on the conservation of S. paramamosain during overwintering. Three salinities (4‰, 12‰ and 25‰) were selected as the overwintering salinities to reveal the effects of different salinities on the relevant important ions in osmotic pressure regulation, plasma cortisol, digestive enzymes, immune enzymes and amino acids of S. paramamosain during indoor overwintering. Results indicated that after overwintering, Cl‐, Na+ and the osmotic pressure of serum have the highest salinity at 25‰, and the lowest salinity at 4‰. Na+/K+‐ATPase activity and cortisol were found to increase with decreasing salinity. The activity of digestive and immune enzymes was highest at 25‰, and was the lowest at 4‰. The amount of total amino acids (TAA), umami amino acids (UAA) and essential amino acids (EAA) in 25‰ were significantly higher than in 4‰ and 12‰. After overwintering, the essential amino acid index (EAAI) in the salinity range of 12–25‰ was 54.04–59.00, compared to 48.56–54.04 in the salinity range of 4–12‰. As a result, S. paramamosain at 25‰ had higher digestion and immunity than at 4‰ and 12‰, due to requiring more energy for osmotic pressure adjustment. In addition, S. paramamosain at 25‰ had the best meat quality. The results of this study are helpful for aquaculture production for indoor overwintering of S. paramamosain.  相似文献   

3.
Three salinities (4‰, 12‰ and 25‰) were selected to determine the effects of different salinities on the growth, survival, nutrition and energy metabolism of Scylla paramamosain during indoor overwintering. Growth performance (survival rate, condition factor, hepatopancreatic index, weight gain rate and specific growth rate), nutrient composition (ash, moisture, crude fat, crude protein and total nitrogen), fatty acids, energy metabolites (glycogen, glucose, triglycerides, cholesterol and lactic acid) and energy metabolic enzymes (hexokinase, pyruvate kinase, lactate dehydrogenase and succinate dehydrogenase) were measured and calculated. The results showed that S. paramamosain exhibited the best growth and survival at 25‰ and worst at 4‰ after overwintering. In addition to consuming crude fat, excess protein was also broken down to provide energy in the 4‰ and 12‰ groups. The content of unsaturated fatty acids in the 25‰ group was higher after overwintering. Glycogen and glucose consumption and triglycerides, cholesterol and lactic acid production were lowest in the 25‰ group. The activity of hexokinase, pyruvate kinase, lactate dehydrogenase and succinate dehydrogenase was highest in the 4‰ group and lowest in the 25‰ group. The activity of hexokinase, pyruvate kinase, lactate dehydrogenase and succinate dehydrogenase in the hepatopancreas was higher than in the muscle. In conclusion, S. paramamosain uses less energy, has more unsaturated fatty acids and has a higher survival rate at a salinity of 25‰ after overwintering. The results of this study provide helpful information the indoor overwintering S. paramamosain in aquaculture production systems.  相似文献   

4.
High lethality of white hepatopancreas syndrome has caused large economic loss of Chinese mitten crab (Eriocheir sinensis). Hepatopancreas colour of diseased crabs is gradually lighter, turning from golden yellow to yellow‐white to white. This study investigated composition of conventional nutrients in three edible parts of different coloured hepatopancreases of adult males, including normal yellow hepatopancreas group (Control), yellow‐white hepatopancreas group (YWH) and white hepatopancreas group (WH). No significant differences were observed in tissue indices and total edible yield among three crab types; however, condition factor level in crabs of YWH and WH was significantly lower. Dry matter content was significantly reduced in crabs of WH, especially crude fat level of hepatopancreas in WH males. Levels of all the amino acids of WH crabs in muscles and gonads were significantly lower than that of control. Proportion of saturated fatty acids and monounsaturated fatty acids were much lower in hepatopancreas of WH crabs than those of control, while proportion of polyunsaturated fatty acids and highly unsaturated fatty acids were significantly higher. Overall, YWH and WH do not affect growth. WH crabs showed poor nutritional quality, and nutritional value of YWH was in the middle as transition state between control and WH.  相似文献   

5.
Chinese mitten crabs (Eriocheir sinensis) were collected after different periods of fattening under salinity (9‰): 0, 15, 30, 45 and 60 d, corresponding to the original phase (OP), initial phase (IP), middle phase (MP), late phase (LP) and final phase (FP) respectively. Biological indicators, proximate composition, free amino acids and flavour nucleotides were determined. The results show that the gonadosomatic index was increased for both genders during fattening, and the higher content of crude protein and lipid was found in IP and MP. The content of free amino acids and umami intensity were significantly higher in most edible tissues than in the overall samples. The contents of flavour nucleotides first increased with fattening time and then decreased in the later phases. However, in female crabs, the content of 5’‐inosine monophosphate increased significantly in LP and FP compared with other phases. The findings indicate that fattening under salinity can increase gonadal index and umami intensity in E. sinensis.  相似文献   

6.
Transformer‐2 (Tra‐2) is an mRNA splicing factor that acts in concert with Tra to regulate the female sexual development in Drosophila melanogaster. In decapods, as no Tra homologues have been identified, the role of Tra‐2 in sexual development is more often discussed accordingly. In the present study, the full‐length cDNA of Tra‐2 of the mud crab Scylla paramamosain (SpTra‐2) was cloned and characterized. The deduced amino acid sequence of SpTra‐2 contained an RNA‐recognition motif (RRM) flanking by two RS‐rich regions, which are the hallmarks of the Tra‐2 proteins. The SpTra‐2 mRNA was highly abundant in the hepatopancreas, muscles and androgenic glands of the male crabs, implying a potential role in male sexual development. The hypothesis was supported by the RNAi experiments, finding that the injection of SpTra‐2 dsRNA in vivo led to a decreased expression of SpIAG, a key gene in crustacean male sexual differentiation. The relationship between SpTra‐2 and SpIAG was further affirmed by eyestalk ablation (ESA) experiments, which caused SpTra‐2 expression earlier than SpIAG expression in both androgenic glands and hepatopancreas. In addition, treatment with SpTra‐2 dsRNA also reduced the mRNA level of SpSxl, but had no effects on SpDmrt expression, suggesting the sex determination system in S. paramamosain is different from that in D. melanogaster.  相似文献   

7.
ABSTRACT

Active nonvolatile taste active compounds—including free amino acids, flavor 5?-nucleotides, lactic acid, succinic acid, and four kinds of inorganic ions in dried Sha-chong (Sipunculus nudus)—were analyzed. The results were then used to calculate taste activity values (TAVs) and equivalent umami concentration (EUC) to evaluate their potential contributions to depth of flavor. Our results showed that the total free amino acid content of dried Sha-chong was 56.62 mg/g; glycine, arginine, and alanine as the major free amino acids, accounting for more than 76% of the total free amino acids; 5?-adenosine monophosphate (AMP) and 5?-inosine monophosphate (IMP) were the main flavor 5?-nucleotides (128.8 and 121.0 mg/100 g); guanosine monophosphate (GMP) was present in a small amount, only 14.6 mg/100 g. Eight amino acids—especially Gly, Arg, and Ala,—three flavor 5?-nucleotides, succinic acid, sodium, potassium, phosphate, and chloride ions were of high TAV greater than 1. The EUC of dried Sha-chong was 49.12 g MSG/100 g, which meant that the dried Sha-chong has a strong umami taste and is suitable for use as umami condiment.  相似文献   

8.
A female swimming crab (Portunus trituberculatus) with fully developed ovaries is considered one of the most nutritious types of seafood. The fishing yield of P. trituberculatus in China has always been high; however, its economic value has been low and unreliable due to poor ovarian development and low nutritional value. Artificial fattening is an effective way to improve the value of wild‐caught crabs, and this study focused on analysing the ovarian development and nutritional quality of the female P. trituberculatus during an artificial fattening period. Therefore, this study provides scientific evidence on the effects of artificial fattening on female P. trituberculatus and can guide the development of nutritional quality regulations for wild‐caught female crabs during the fattening process. The results showed that the ovaries of the wild female P. trituberculatus developed gradually. The ovarian morphology became bulkier, while the gonadosomatic index (GSI) and total edible yield (TEY) were significantly improved after artificial fattening. Significant changes in the nutritional components of the edible tissues were observed, and the moisture content in the ovaries and hepatopancreas decreased continually, while both the protein and fat content in the ovaries significantly increased. Moreover, the fat content in the hepatopancreas significantly increased. The saturated fatty acids(ΣSFA) in the ovaries and hepatopancreas had an increasing trend after fattening, while ΣPUFA and Σn‐3PUFA first decreased and then increased. In contrast, the ratio of Σn‐3PUFA to Σn‐6PUFA decreased steadily. However, the fatty acid composition of the muscles did not change significantly. The levels of all the amino acids increased continuously during the fattening process, and EAA increased significantly in the early stages of the fattening period. Consequently, all amino acids became nonlimiting amino acids after fattening. Furthermore, the ratio of EAA/NEAA in the ovaries increased continually until the end of the fattening period. On the other hand, the fatness and TEY increased significantly after artificial fattening. In addition, the nutritional value significantly improved with the exception of the high‐quality fatty acids in the ovaries and hepatopancreas, which were slightly lower in both.  相似文献   

9.
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10.
The nutritional values of edible gonad, hepatopancreas and muscle tissues from normal and precocious adult male Chinese mitten crabs (Eriocheir sinensis) were investigated herein. The results showed that the average weight and meat yield (MY) of normal crabs were significantly higher than those of precocious crabs, while the hepatopancreas indexes (HSI) and gonadosomatic indexes (GSI) had no significant differences. Precocious and normal crabs had greater protein and lipid contents, respectively, and the differences were mainly reflected in gonads and hepatopancreas. While assessing the amino acid profiles, both precocious and normal crabs could be high‐quality protein sources, particularly the precocious crabs which showed higher levels of essential amino acids. In fatty acid profiling experiments, precocious crabs revealed higher EPA, ∑n‐3 polyunsaturated fatty acids (PUFA) and ∑n‐3/∑n‐6 ratios than normal crabs; however, DHA and ∑n‐6 PUFA contents were considerably lower. Additionally, contents of nutritious minerals K and Ca in precocious crabs were significantly higher than those in normal crabs, while Zn and Fe were significantly lower. In short, our data indicated that precocious Chinese mitten crabs are also a nutritious food, and even in some respects their nutritional value is higher than normal crabs.  相似文献   

11.
本研究分析不同水域中华绒螯蟹(Eriocheirsinensis)可食率和滋味差异,以期为挖掘消费者不同偏好性的内在原因提供参考.选取阳澄湖、固城湖、太湖和兴化大闸蟹为研究对象,测定可食率、整体滋味轮廓、滋味相关指标.结果显示,太湖蟹可食率最高,雄蟹为(33.08±0.31)％,雌蟹为(37.65±1.09)％;在整体...  相似文献   

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13.
秋季不同时期上市中华绒螯蟹可食率和品质比较   总被引：1，自引：1，他引：0  
为全面了解中华绒螯蟹（Eriocheir sinensis）可食率和品质差异,对秋季不同时期上市的中华绒螯蟹可食率和品质进行了比较。在种植了伊乐藻（Elodea nuttallii）的池塘中,按照生态健康养殖的方法,养殖中华绒螯蟹扣蟹至成蟹。采用解剖和生化组成分析等方法探究秋季不同时期中华绒螯蟹的可食率、常规营养成分、脂肪酸和游离氨基酸组成及其含量。结果表明：（1）不论是雌体还是雄体,9月和10月肝胰腺指数（HSI）和性腺指数（GSI）均存在显著性差异（P<0.05）,出肉率（MY）、总可食率（TEY）和肥满度（CF）则无显著性差异（P>0.05）。仅HSI指标9月高于10月,其余指标均是10月较高。（2）9月和10月常规营养成分无显著差异项（P>0.05）较多,但雌体肝胰腺中水分、总脂,性腺中总脂,肌肉中水分和粗蛋白含量存在显著性差异（P<0.05）;雄体性腺中粗蛋白、总脂、灰分,肌肉中总脂含量存在显著性差异（P<0.05）。（3）9月和10月成蟹肝胰腺中仅1种脂肪酸含量差异显著（P<0.05）,占比为1/52,其余脂肪酸含量均无显著差异（P>0.05）;性腺中仅2种脂肪酸显著差异（P<0.05）,占比为2/52,其余均无显著性差异（P>0.05）;肌肉中11种脂肪酸显著差异（P<0.05）,占比为11/52,其余均无显著差异（P>0.05）。（4）9月和10月成蟹性腺中1种游离氨基酸显著差异（P<0.05）,占比为1/52,其余均无显著性差异（P>0.05）;肌肉中仅雄体牛磺酸（Tau）、丙氨酸（Ala）和亮氨酸（Leu）差异显著（P<0.05）,占比为3/52,其余均无显著性差异（P>0.05）。综上所述,中华绒螯蟹10月GSI、MY、TEY和CF高于9月,常规营养成分存在一定差异,性腺中脂肪酸和游离氨基酸含量差异较小,而肌肉中脂肪酸含量差异较大。整体上10月中华绒螯蟹可食率和品质要优于9月。  相似文献   

14.
以不同收割期的靖海湾条斑紫菜(Pyropia yezoensis)为研究对象,对比分析营养价值并评价其鲜味。通过测定基本营养成分、无机元素组成和氨基酸组成,分析其营养学特征,通过测定游离氨基酸与呈味核苷酸组成,进而计算滋味活性值(Taste active value, TAV)与味精当量(Equivalent umami concentration, EUC)。结果显示,靖海湾条斑紫菜蛋白质含量丰富,头水和二水紫菜的蛋白含量均在49%以上,显著高于四水和六水紫菜(P<0.05)。不同收割期条斑紫菜的脂肪含量较低,均小于1.1%。常量元素中P含量最低,K含量最高,约为2.59×104~5.52×104 mg/kg;微量元素以Fe含量最高,Zn次之,Co最低;Pb含量明显低于GB 2762-2017的限量要求。头水、二水紫菜与四水、六水紫菜的必需氨基酸及氨基酸总量间存在显著差异(P<0.05)。游离谷氨酸和次黄嘌呤核苷酸对条斑紫菜的鲜味起主要贡献作用,头水、二水、四水和六水紫菜的EUC(以干基计)依次降低,分别为239.71、190.03、108.05和51.56 g MSG/100 g。靖海湾条斑紫菜具有较高的营养价值,且收割前期的靖海湾条斑紫菜鲜味度较高,可作为开发调味品的原料。  相似文献   

15.
A 6‐week study was conducted to determine the effects of different lipid sources in pelleted diets on juvenile mud crab Scylla paramamosain. Five isonitrogenous and isolipidic diets containing 8% level of fish oil (FO), lard (LD), safflower oil (SO), perilla seed oil (PO) or mixture oil (MO; VFO:VSO:VPO = 1:1:1), and a live food of marine bivalve Potamocorbula rubromuscula as the control diet (CF), were fed to groups of 25 juvenile crabs (average initial weight 7.4 g, carapace width 3.5 cm) in triplicate. The results showed that crabs fed MO had the highest survival (P < 0.05). The moisture content was significantly higher in crabs fed LD, SO and PO (P < 0.05). Crabs fed SO exhibited the lowest crude protein and lipid (P < 0.05). Ash contents were obviously lower in LD group (P < 0.05). Highest total lipid in the hepatopancreas and muscle was in LD and FO group respectively. Glucose, total cholesterol and low‐density lipoprotein were higher while high‐density lipoprotein was lower (P < 0.05) in LD group. Tissue fatty acid compositions were consistent with those in diets. FO and MO diets had the same depression effect like CF on fatty acid synthase activity and mRNA expression in the hepatopancreas. The results of this study indicated that FO and mixed oil are suitable for preparation of pelleted diets with better effects for juvenile S. paramamosain compared with live food, and the ratio of n‐6/n‐3 fatty acids in pelleted diets must be <1.  相似文献   

16.
The present study was to determine the time‐dependent alterations in growth performance, histomorphology, digestive enzymes activities and the genes expression related to target of rapamycin (TOR) signalling pathway involved in hepatopancreas and intestine of Litopenaeus vannamei at 3, 6, 12, 18, 24 and 30 days after Aflatoxin B1 (AFB1) challenge. The results manifested that AFB1 could induce a significant decrease in growth performance and visible variations of the hepatopancreas and intestine structures in shrimp. Meanwhile, the digestive enzymes activities and genes expression level were significantly lower in the experimental group than in the control group and showed a time‐dependent decrease (p < 0.05). The expression levels of tor and s6k were significantly higher in the experimental group than in the control group from days 6 to 24 and showed a tendency to increase first and then decrease as a whole (p < 0.05). Meanwhile, we analysed candidate pathways involved in hepatopancreas and intestine of shrimp in metabolic response to AFB1. The mainly disturbed pathways related to metabolism in hepatopancreas were involved in pyrimidine, glycosylphosphatidylinositol, glycosaminoglycan, vitamin and amino acid biosynthesis and metabolism, while the mainly disturbed metabolic pathways in intestine were glycosaminoglycan, vitamin and amino acid biosynthesis and metabolism.  相似文献   

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18.
基于电子舌技术分析不同采收期紫菜的滋味特征   总被引：1，自引：0，他引：1       下载免费PDF全文
为科学评价不同采收期的紫菜在滋味方面的差异,采用电子舌技术分析了头水、二水、四水和六水条斑紫菜(Porphyra yezoensis)的滋味组成,同时,对不同采收期紫菜中游离氨基酸、呈味核苷酸等呈味物质的含量进行了测定。结果显示,紫菜滋味主要由鲜味、鲜味回味、咸味和苦味组成。头水、二水、四水和六水紫菜的鲜味强度依次减弱。二水紫菜的鲜味回味值最大,头水和四水紫菜的鲜味回味值接近,六水紫菜的鲜味回味值显著降低(P<0.05)。头水和二水紫菜的咸味强度接近,且显著高于后期采收紫菜的咸味值(P<0.05)。头水、二水紫菜的苦味值接近,四水紫菜的苦味值略低,六水紫菜的苦味值最低。不同采收期紫菜的呈味物质含量及其对滋味的贡献程度差异较大。头水、二水、四水和六水紫菜的游离氨基酸总量依次减少,4组样品之间存在显著差异(P<0.05),对滋味贡献大的游离氨基酸主要是丙氨酸和谷氨酸。呈味核苷酸中肌苷酸(Inosine monophosphate,IMP)对滋味的贡献大。头水、二水、四水和六水紫菜的味精当量(Equivalent umami concentration,EUC)分别为223.89、222.13、118.54和47.19 g MSG/100 g,研究表明,前期采收的紫菜鲜味更加强烈。电子舌的检测数据与呈味物质含量的分析结果基本一致。  相似文献   

19.
Nonvolatile taste active compounds, including free amino acids (FAAs), 5′-nucleotides, betaine, soluble sugars, trimethylamine oxide and organic acids of wild and cultured mud crab Scylla paramamosain were examined. The main taste in mud crab (MC) is derived from the FAAs, 5′-nucleotides, betaine, and organic acids, based on the fact that these compounds have a taste activity value (TAV)?>?1. Wild MCs had a higher content of total FAAs, 5′-nucleotides, betaine, and organic acids in meat compared with cultured animals. However, no differences in the taste active compound levels were observed in the gonads of wild and cultured MCs, with betaine being the exception (wild crab?>?cultured crab). The total concentrations of FAAs in MC ranged from 12.71 to 36.94 mg/g. Monosodium glutamate (MSG)-like FAAs were primarily contributed by glutamic acid, and ranged from 0.71 to 0.93 mg/g. The concentrations of 5′-nucleotides were 1.10–2.24 mg/g, in which 5′-inosine monophosphate (IMP) and 5′-adenosine monophosphate (AMP) were the predominant TAVs (TAV?>?1). The total concentrations of organic acids in MC were 2.41–11.10 mg/g, in which lactic and succinic acid in meat, and citric acid and succinic acid in female gonads were the main organic acids. The gonads were observed to have higher concentrations of 5′-nucleotides and organic acids compared with crab meat, with the equivalent umami concentration in gonads being higher than that in crab meat. In conclusion, wild MCs contained more active-taste nonvolatile flavor components relative to those detected in cultured MCs.  相似文献   

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