盐度胁迫对三疣梭子蟹(Portunus trituberculatus)鳃中游离氨基酸含量的影响

本研究分析了不同盐度环境下三疣梭子蟹(Portunus trituberculatus)鳃组织中游离氨基酸(FAAs)的含量及浓度变化规律,明确FAAs的组成及其在盐度适应中发挥的功能。结果显示,在正常海水中,三疣梭子蟹鳃组织中牛磺酸(Tau)的浓度最高(2.54 mg/g),其次分别为丙氨酸(Ala,0.65 mg/g)、谷氨酸(Glu,0.64 mg/g)、精氨酸(Arg,0.58 mg/g)、甘氨酸(Gly,0.48 mg/g)和脯氨酸(Pro,0.25 mg/g);在盐度10–50范围内,梭子蟹鳃中总游离氨基酸(TOFAA)的含量随盐度的增加而显著升高(P0.05),盐度50时,TOFAA的含量为盐度10时的1.48倍。进一步分析发现,非必需氨基酸(NEAA)(Gly、Glu、Ala和Pro)的浓度随盐度的升高而上升,而必需氨基酸(EAA)的浓度变化不显著(P0.05)。研究表明,FAAs在三疣梭子蟹盐度适应中具有重要功能,其中发挥渗透调节功能的主要为NEAA。     

盐度胁迫对三疣梭子蟹肌肉和血淋巴中游离氨基酸含量的影响

为探究不同盐度环境下三疣梭子蟹肌肉和血淋巴中游离氨基酸(free amino acids,FAAs)的含量及浓度的变化规律,明确FAAs的组成以及在盐度适应中发挥的作用,丰富FAAs在甲壳动物盐度适应领域的研究,为后续分子机理的研究提供依据,实验设定胁迫盐度分别为10、20、40、50,以正常海水(盐度33)为对照,用日立835-50型氨基酸自动分析仪测定三疣梭子蟹血淋巴与肌肉组织中游离氨基酸的组分,分析不同盐度环境下三疣梭子蟹肌肉和血淋巴中FAAs的含量及变化规律。结果显示,在正常海水中三疣梭子蟹血淋巴和肌肉中含量较高的FAAs主要为牛磺酸(Tau)、精氨酸(Arg)、甘氨酸(Gly)、脯氨酸(Pro)和丙氨酸(Ala)。盐度为10~50,梭子蟹肌肉和血淋巴总游离氨基酸(total free amino acid,TOFAA)的含量随盐度的增加而显著升高,非必需氨基酸(non-essentical free amino acid,NEAA)的含量随盐度的升高而上升,而必需氨基酸(essentical free amino acid,EAA)的含量变化不显著,因此,TOFAA在渗透压调节方面的作用主要取决于NEAA。发挥主要渗透压调节作用的FAAs为脯氨酸(Pro)、丙氨酸(Ala)、甘氨酸(Gly)、天冬氨酸(Asp)、谷氨酸(Glu)。Ala、Gly、Asp、Glu属于鲜味氨基酸(taste amino acid,TAA),研究表明,NEAA中的TAA在渗透压调节方面作用显著,Pro含量的升高对TOFAA含量的增加作用显著,盐度为40~50尤甚,表明Pro在梭子蟹高渗调节中发挥重要作用。     

盐度对凡纳滨对虾肌肉中游离氨基酸含量的影响

通过逐渐升高盐度的方法,分别测定盐度为0、10、20、30和40时凡纳滨对虾肌肉中游离氨基酸(FAA)的含量,实验周期40 h。结果表明:在盐度0~40时,总游离氨基酸(TOFAA)、必需氨基酸(EAA)、非必需氨基酸(NEAA)和鲜味氨基酸(TAA)的含量都随盐度的增加而明显升高(P0.05);特别是当盐度从20增加到30时,肌肉中TOFAA、EAA、NEAA和TAA含量的增高幅度最明显。在凡纳滨对虾肌肉FAA中,含量最高的是甘氨酸(Gly),其次是脯氨酸(Pro)、精氨酸(Arg)和丙氨酸(Ala)。在盐度为0~40范围内,肌肉中主要的渗透压调节因子是甘氨酸(Gly)、脯氨酸(Pro)、精氨酸(Arg)、丙氨酸(Ala)和牛磺酸(Tau);而天冬氨酸(Asp)、丝氨酸(Ser)、缬氨酸(Val)、甲硫氨酸(Met)、异亮氨酸(Ile)、亮氨酸(Leu)和酪氨酸(Tyr)的含量在各盐度组未呈现显著变化(P0.05)。在淡水养殖凡纳滨对虾出售前的40 h,通过提高水体盐度来提高凡纳滨对虾肉质的鲜味是完全可行的。     

盐度骤变南美白对虾肌肉中游离氨基酸的组成分析

本实验将南美白对虾分别放入盐度为0‰、10‰、20‰、30‰、40‰、50‰水体暂养5 min,取其肌肉测定游离氨基酸含量.结果表明,在南美白对虾肌肉中,游离氨基酸含量最高的是甘氨酸(Gly),其次是精氨酸(Arg)、脯氨酸(Pro)和丙氨酸(Ala).在5 min内,盐度为10‰时,游离氨基酸总浓度达最高,为221.587 μmol/g鲜重,比盐度为0‰和50‰时分别提高11.7%和10.85%,差异显著(P＜0.05).其中,天冬氨酸(Asp)丝氨酸(Ser)、甘氨酸(Gly)、半胱氨酸(Cys)、缬氨酸(Val)、蛋氨酸(Met)、亮氨酸(Leu)、酪氨酸(Tyr)、苯丙氨酸(Phe)、赖氨酸(Lys)、精氨酸(Arg)等11种氨基酸在不同盐度中其浓度变化存在显著差异(P＜0.05),其余无显著变化.     

禁食状态下凡纳滨对虾游离氨基酸的降解代谢

在禁食胁迫下,对在盐度为0(S0)和30(S30)水体中的凡纳滨对虾肌肉游离氨基酸(FAA)的浓度变化进行测定.结果表明,禁食15d后,两种盐度中的凡纳滨对虾肌肉游离氨基酸总量均有所升高,但其中游离的牛磺酸(Tau)、苏氨酸(Thr)、脯氨酸(Pro)、丙氨酸(Ala)、半胱氨酸(Cys)、缬氨酸(Val)、蛋氨酸(Met)、异亮氨酸(Ile)、亮氨酸(Leu)、苯丙氨酸(Phe)、赖氨酸(Lys)、组氨酸(His)的浓度却有不同程度的降低,脯氨酸(Pro)在禁食15d后的浓度降为0,牛磺酸(Tau)、苏氨酸(Thr)、丙氨酸(Ala)、半胱氨酸(Cys)、苯丙氨酸(Phe)、赖氨酸(Lys)的降幅也比较显著(P<0.05);但甘氨酸(Gly)、天门冬氨酸(Asp)、酪氨酸(Tyr)、精氨酸(Arg)等主要游离氨基酸的浓度却显著升高,从而使游离氨基酸总浓度升高.实验表明,凡纳滨对虾肌肉里游离氨基酸浓度在禁食胁迫下降解代谢强度不一,饲料中添加脯氨酸(Pro)、精氨酸(Arg)和赖氨酸(Lys)等游离氨基酸后,可能会对凡纳滨对虾的生长起到促进作用.     

海带“东方7号”氨基酸季节变化分析与评价

采用反相高效液相色谱法,对海带"东方7号"3—7月的游离氨基酸和总氨基酸含量及氨基酸组成情况进行分析,并对总氨基酸中必需氨基酸进行评分。结果显示,3—7月,游离氨基酸的含量为9.78~37.59mg/g,在3—6月呈线性增加,7月略有降低;游离氨基酸的组成主要以呈味氨基酸为主(91.82%~98.53%),其中谷氨酸含量在游离氨基酸的季节变化中起决定性作用。总氨基酸的含量占海带质量的6.71%~9.38%,最大值出现在5月;总氨基酸的组成中,必需氨基酸含量随生长时间呈降低趋势,占总氨基酸含量的19.97%~42.94%。必需氨基酸评分最大值出现在5月,为68分。     

杂交海胆性腺氨基酸组成的研究

测定了父本、母本性腺丰满期三个月的杂交海胆(Strongylocentrotus intermedius×S.nudus)氨基酸组成。结果表明,杂交海胆氨基酸含量(400.5~490.8 mg/g)、必需氨基酸含量占氨基酸总量的百分比(46.33%~51.09%)和鲜味氨基酸含量(169.5~228.4 mg/g)均较高,鲜味氨基酸含量占总氨基酸含量超过41%。杂交海胆中甘氨酸含量最高(41.1 mg/g~56.1 mg/g),谷氨酸含量(33.9~49.1 mg/g)次之。杂交海胆棘颜色深浅与氨基酸组成差别不大。杂交海胆蛋氨酸含量、蛋氨酸与缬氨酸含量均略高于父本、母本,海胆味较浓。     

皮氏蛾螺肌肉营养成分分析与评价

采用生化手段对皮氏蛾螺肌肉中营养成分进行检测与分析。结果表明:皮氏蛾螺肌肉中水分含量为75.78%,蛋白质含量为15.70%,脂肪含量为0.50%,灰分含量为1.50%。皮氏嫂螺肌肉氨基酸总含量为58.21 g/100 g,共检测出17种氨基酸:半胱氨酸(Cys)含量最高,含量为11.35 g/100 g,其次是精氨酸(Arg)、天冬氨酸(Asp)和甘氨酸(Gly),组氨酸(His)含量最低,含量为0.39 g/100 g。共检测到6种呈味氨基酸,分别为天冬氨酸(Asp)、丝氨酸(Ser)、谷氮酸(Glu)、甘氨酸(Gly)、丙氨酸(Ala)及脯氨酸(Pro)。呈味氨基酸(DAA)总量为23.07 g/100 g。共检测出25种脂肪酸,其中包括9种饱和脂肪酸(SFA),16种不饱和脂肪酸(UFA)。在所有脂肪酸中,二十碳五烯酸EPA(C20:5i3)含量最高,达19.75%;而十五碳一烯酸(C15:1)含量最低,仅0.26%。     

脆肉鲩肌肉游离氨基酸初步分析

采用气相色谱仪测定来自于同一养殖场的脆肉鲩和普通草鱼肌肉游离氨基酸含量，测得脆肉鲩肌肉游离氨基酸总量为762．96mg／hg，其中必需氨基酸为281、67mg／hg；普通草鱼肌肉游离氨基酸总量为406、29mg／hg,其中必需氨基酸含量为108、54mg／hg。通过和其它鱼的肌肉游离氨基酸比较，探讨了脆肉鲩肌肉结构和口感发生改变的原因。     

金鳙和黑鳙的肌肉营养成分分析及评价

采用国标(GB)检测方法,依据FAO/WHO的评价规定,对2010年发现于常德珊珀湖后经人工选育的金鳙和2015~2016年采样于常德珊泊湖的黑鳙(Aristichthys nobilis)进行肌肉营养成分分析和评价。结果表明,金鳙肌肉鲜样的水分、粗蛋白、粗脂肪、灰分水平分别为76.1%、20.6%、0.52%、1.1%,黑鳙的相应指标为76%、19.8%、0.48%、1.2%,其中两者间粗脂肪含量有显著性差异。金鳙和黑鳙的肌肉干样中17种氨基酸总含量分别为88.69 g/100 g和87.68 g/100 g、鱼类必需氨基酸含量为43.2 g/100 g和42.63 g/100 g、呈味氨基酸含量为32.52 g/100 g和32.32 g/100 g,没有显著性差异。两者肌肉氨基酸含量高低的排序也一致,含量最高的均为Glu,其次为Asp、Lys、Leu,含量最低的为Pro;必需氨基酸中含量最高的是Lys、Leu,最低的是Met。两种鳙鱼间除2种含硫氨基酸(Met、Cys)和组氨酸(His)含量有显著性差异外,其他氨基酸含量基本一致。从AAS和CS评分值可见,两者的限制性氨基酸均为Val、Ile或Thr。两者的必需氨基酸指数(EAAI)为80.47和80.13。研究说明,人工选育的金鳙具有与天然水域鳙鱼相当的营养品质。     

三疣梭子蟹幼体消化酶活力及氨基酸组成的研究

在三疣梭子蟹幼体发育过程中，五种消化酶活力表现出三种变化模式，其中胃蛋白酶和类胰蛋白酶活力呈上升趋势，而且在蚤状幼体Ⅰ期时就较高，淀粉酶活力逐渐减小，纤维素酶和脂肪酶活力极微。氨基酸含量随幼体发育逐渐增加。必需氨基酸中以亮氨酸含量最高，色氨酸含量最低；非必需所基酸中含量最高者为谷氨酸，最低者为胱氨酸。同时单个必需氨基酸含量与必需氨基酸总量的比值（Ａ／Ｅ）在幼体不同发展阶段略有差异，但基本趋于一致。     

Chemical Characteristics of Different Tissues of Spectacled Caiman (Caiman crocodilus)

Proximate compositions of dorsal, ventral, leg, and tail cuts of farmed spectacled caiman (Caiman crocodilus) were determined. The water, protein, fat, and ash contents of muscle were 77–78%, 19–23%, 0.3–1.2%, and 1.0%, respectively. The dominant nucleotide-related compound in the tissues was inosine monophosphate (IMP) (68.6–84.9%). The predominant free amino acids (FAAs) in the muscle of spectacled caiman were taurine (Tau), glycine (Gly), alanine (Ala), and histidine (His), along with a dipeptide of anserine (Ans) (80–183 mg/100 g) and carnosine (Car) (35–103 mg/100 g) being detected in each sample. The major fatty acid composition included palmitic (16:0), oleic (18:1 cis-9), linoleic (18:2n-6), and stearic (C18:0) acids. The amount of docosahexaenoic acid (4.27–8.76%) was higher than that of eicosapentaenoic acid (0.99–2.24%). The ratio of polyunsaturated fatty acid/saturated fatty acid in spectacled caiman (0.83–1.19) was higher than that in other commonly consumed meat. Meat from the spectacled caiman can be characterized as a valuable food for human consumption in terms of these nutritional features.     

Differences in free amino acid composition between testis and ovary of sea urchin <Emphasis Type="Italic">Anthocidaris crassispina</Emphasis> during gonadal development

ABSTRACT:   For the purpose of clarifying the differences of taste components between the testis and ovary of the sea urchin Anthocidaris crassispina , variations in free amino acid composition in gonadal extract during gonadal development were investigated using chemical and histopathological methods. Sea urchins were collected at Iki Island, Nagasaki, Japan between 30 April and 5 June 2003, and maturation stages and the free amino acid compositions were determined. The sweet amino acids threonine (Thr), glycine (Gly), and alanine (Ala), the umami amino acid glutamic acid (Glu), and the bitter amino acids lysine (Lys) and arginine (Arg) were the main constituents accounting for more than 80% of total free amino acids. In the testis and ovary, Gly levels were the highest among them and increased with gonadal development. The other free amino acids consisted mainly of bitter amino acids and either showed no variation or decreased with gonadal development. These variations in free amino acid composition were observed more clearly in the ovary than the testis. These findings indicate the possibility of differences in the flavor of sea urchin gonad by sex and gonadal development stages.     

The amino acid profiles in developing eggs and larvae of the freshwater Percichthyid fishes,trout cod,Maccullochella macquariensis and Murray cod,Maccullochella peelii peelii

Results on changes in the total amino acids (protein bound + free) and the free amino acids (FAA) in relation to development, from egg (unfertilised and/or fertilised) to yolk-sac resorbed larva, before first feeding, in two Percichthyid fish, trout cod, Maccullochella macquariensis and Murray cod, Maccullochella peelii peelii, which lay demersal, adhesive eggs, are presented. Throughout development, the FAA accounted for only a small proportion (0.19 % in fertilised eggs of both species) of the total amino acid pool. Nine essential amino acids (EAA) and eight non-essential amino acids (NEAA) were quantified in the amino acid pool at all stages of development. In both species, the total amino acid content decreased during the transformation (at 20 ± 1 °C) from newly hatched larva to yolk-sac resorbed larva. Overall, the changes in the TEAA and TNEAA reflected that of the amino acid pool. In trout cod, all but one EAA (lysine) and two NEAA (cysteine and glycine) decreased with ontogeny, from fertilised egg to yolk-sac resorbed larva. In Murray cod, however, the exceptions to the general decline were two NEAA (aspartic acid and glycine). In contrast, the FAA increased with development, the changes being reflected in both FEAA and FNEAA. Qualitatively, the predominant free amino acids in trout cod and Murray cod eggs were alanine, lysine, leucine and serine. Because the egg protein and the total amino acid contents declined with development, it is concluded that the rate of breakdown of yolk protein was higher than the anabolic and catabolic processes during embryogenesis. Data also suggest that in freshwater fish FAA are an unlikely primary energy substrate during embryogenesis.     

Calculated Taste Activity Values and Umami Equivalences Explain Why Dried Sha-chong (Sipunculus nudus) Is a Valuable Condiment

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.     

不同盐度对凡纳滨对虾血淋巴及肌肉游离氨基酸组成的影响

以平均体重为10.50±1.75g的凡纳滨对虾为研究对象,分别在盐度为0、15和30的水体中用同一种饲料喂养20d,探讨不同盐度对凡纳滨对虾肌肉及血淋巴游离氨基酸组成的影响。结果表明,盐度在0、15和30变化时,凡纳滨对虾血淋巴中总游离氨基酸总量随盐度升高而显著增加（P〈0.05）;甘氨酸、谷氨酸、精氨酸和丙氨酸是凡纳滨对虾血淋巴中主要的游离氨基酸成分,其含量随盐度的增加而急剧增加。盐度为0、15和30时,凡纳滨对虾肌肉中游离氨基酸总量随着盐度的增加有增加趋势,但无显著性差异（P〉0.05）。甘氨酸、亮氨酸、苯丙氨酸及精氨酸的含量随盐度由0、15、30的增加而显著增加（P〈0.05）;其他氨基酸在盐度0、15和30增加时,虽无显著性增加（P〉0.05）,但大部分氨基酸有增加趋势。当盐度在0、15和30变化时,游离甘氨酸、谷氨酸、精氨酸和丙氨酸是凡纳滨对虾体内渗透压调节的主要氨基酸。     

察尔森水库细鳞斜颌鲴营养成分分析及评价

本试验对察尔森水库细鳞斜颌鲴(Plagiognathops microlepis)肌肉营养成分进行了分析及评价。试验采用常规营养成分分析法对细鳞斜颌鲴肌肉一般营养成分、氨基酸组成、脂肪酸组成进行了测定。结果表明:细鳞斜颌鲴肌肉中水分含量为79.31%、粗蛋白含量为16.56%、粗脂肪含量为0.94%、灰分含量为1.13%、总糖含量为0.38%。细鳞斜颌鲴肌肉共检出18种氨基酸,其中必需氨基酸(EAA)8种,非必需氨基酸(NEAA)10种,总氨基酸(TAA)含量为16.28%,EAA含量为6.72%,NEAA含量为9.56%;EAA/TAA(41.29%)及EAA/NEAA(70.32%)均在FAO/WHO推荐值以上。氨基酸评分(AAS)和化学评分(CS)结果是第一限制性氨基酸均为色氨酸(Trp),而第二限制性氨基酸,AAS是苏氨酸(Thr),CS是苯丙氨酸+酪氨酸(Phe+Tyr)。细鳞斜颌鲴肌肉共检出21种脂肪酸,其中7种饱和脂肪酸(SFA)、3种单不饱和脂肪酸(MUFA)、11种多不饱和脂肪酸(PUFA),分别占脂肪酸总量的25.22%、22.02%、37.76%;C20∶5n3(EPA)含量为11.87%,C22∶6n3(DHA)含量为11.55%。从营养分析结果来看,细鳞斜颌鲴是一种营养价值极高的食用鱼类。