Physicochemical Changes in Pacific Whiting Muscle Proteins during Iced Storage

No changes in actomyosin Ca²⁺-, Mg²⁺-, or Mg²⁺-Ca²⁺-ATPase activities were observed during iced storage of Pacific whiting fillets, but Mg²⁺-EGTA-ATPase increased with a loss of Ca²⁺-sensitivity. Surface hydrophobicity of actomyosin increased substantially within 2 days, but not total sulfhydryl (SH) content. During longer storage, the SH content decreased gradually, but surface hydrophobicity remained constant. Autolytic degradation products increased in fish muscle with storage time. Myosin heavy chain (MHC) was degraded by 45% within 8 days, but no noticeable difference was observed in actin. Results indicated that autolysis may be the main cause of physicochemical changes in Pacific whiting muscle proteins during iced storage.     

生长过程中池塘养殖胭脂鱼幼鱼鱼体与蛋白营养变化

采用国标(GB)的检测方法,对生长过程中池塘养殖胭脂鱼幼鱼鱼体与蛋白营养变化进行了研究.结果表明:鱼体组成中,29月龄幼鱼的粗蛋白含量最高,与5月龄无显著差异(p＞0.05),17月龄最低;粗脂肪和灰分含量分别是17、29月龄幼鱼含量最高,29、17月龄最低.肌肉百分含量和肌肉中粗蛋白、粗脂肪以及灰分含量随着月龄的增加而显著降低,而水分含量却随着月龄的增加而显著升高.肌肉氨基酸总量中,29月龄的最高,17月龄的最低.41月龄幼鱼肌肉中必需氨基酸含量最高,且与29月龄无显著性差异(p＞0.05).各龄幼鱼均是Glu含量最高,其次是Asp,含量最低的为Cys.17、29、41月龄幼鱼的第一限制性氨基酸分别为Leu、Thr、Thr和Val,必需氨基酸指数分别为55.38、68.19和69.04.综合各项指标,29月龄幼鱼蛋白营养高于17月龄和41月龄的.     

丁香酚麻醉大口黑鲈的保活温度优化

为探讨温度对有水保活大口黑鲈代谢与肌肉品质的影响,研究了不同丁香酚浓度对大口黑鲈的麻醉效果。选取最佳浓度麻醉大口黑鲈,分别在5,10,15和20 ℃的条件下保活,测定了不同温度下的存活率、氨氮含量、血液生化指标与肌肉品质的变化。结果显示：大口黑鲈的较佳丁香酚浓度为18 mg/L,在5 ℃保活72 h存活率为0,在10、15和20 ℃下保活96 h后的存活率分别100%,75%和0%;随着保活时间延长,与15 ℃,20 ℃组相比,10 ℃组的总氨氮降低24.12%~51.24%,血糖含量先增加后下降,保活72 h后,10 ℃处理组血清中皮质醇、谷草转氨酶、谷丙转氨酶、碱性磷酸酶和尿素氮分别比20 ℃组低260.44 pg/mL、52.54 mmol/L、8.76 mmol/L、3.26 mmol/L和8.22 mmol/L（p<0.05）,而溶菌酶、总抗氧化能力和谷胱甘肽过氧化物酶含量均显著高于其它组（p<0.05）;10 ℃肝脏HSP90的表达量显著低于15 ℃和20 ℃;肌肉指标中,15 ℃和20 ℃组糖原、粗蛋白含量和pH显著低于10 ℃组。表明10 ℃保活条件下大口黑鲈抗氧化物酶活性增强,应激降低,肌肉品质影响较小。因此,10 ℃适合大口黑鲈的长途保活运输。     

热处理对茶花鸡肌肉中脂肪酸组成的影响

为研究热处理对茶花鸡肌肉中脂肪酸组成的影响,本文以300日龄的云南本地茶花鸡公鸡的胸肌和腿肌为研究对象,采用气相色谱-质谱法(GC-MS)检测胸肌和腿肌中脂肪酸含量,对其脂肪酸含量进行差异分析。结果表明在茶花鸡肌肉中共检测出32种脂肪酸,其主要脂肪酸为油酸、棕榈酸、亚油酸、花生四烯酸、硬脂酸及肉豆蔻酸。在原料肉中,胸肌和腿肌中总脂肪酸含量分别为3242.41与10026.31 μg/g,部位间存在显著性差异(P<0.05);胸肌与腿肌中脂肪酸类型以不饱和脂肪酸为主,含量分别占32种脂肪酸总量的60.92%与63.55%。经热处理后,胸肌中总脂肪酸含量比加热前胸肌中降低了9.37%(P<0.05),腿肌中总脂肪酸含量比加热前腿肌中降低了22.15%(P<0.05);胸肌、腿肌中脂肪酸以不饱和脂肪酸为主,不饱和脂肪酸含量分别占32种脂肪酸总量的59.38%与61.20%;胸肌和腿肌之间脂肪酸含量差异显著(P<0.05),腿肌的饱和脂肪酸(SFA)、单不饱和脂肪酸(MUFA)、多不饱和脂肪酸(PUFA)含量与胸肌有显著差异(P<0.05)。可见,茶花鸡胸肌和腿肌脂肪酸含量存在显著差异,热处理对茶花鸡胸肌和腿肌脂肪酸组成有明显影响。     

中国大鲵肌内脂肪酸组成及其抗氧化研究

分析中国大鲵肌内脂肪酸的组成,并研究肌内脂肪酸抗氧化,提供肌内脂肪酸开发利用的基础理论。通过气相色谱/质谱联用技术分析肌内脂肪酸的组成;通过Schaal烘箱法(63±1℃)研究肌内脂肪酸的抗氧化特性。GC-MS分析结果表明:肌内脂肪主要含13种脂肪酸,其含量由高到低依次为,C18∶124.2%,C16∶015.4%,C16∶113.7%,C18∶28.2%,C20∶56.7%,C18∶34.5%,C22∶64.3%,C14∶13.0%,C18∶02.8%,C22∶52.6%,C20∶42.2%,C17∶02.0%,C17∶11.9%。饱和脂肪酸(SFA)为20.2%,不饱和脂肪酸(UFA)达71.3%。单不饱和脂肪酸(MUFA)为42.8%,多不饱和脂肪酸(PUFA)为28.5%,具有保健功能性作用的ω-6型PUFA为13.0%,ω-3型PUFA为15.5%。ω-6型与ω-3型PUFA比为0.8。Schaal烘箱法研究结果表明:抗氧化剂二丁基对甲苯酚(BHT)、没食子酸丙酯(PG)、特丁基对苯二酚(TBHQ)对肌内脂肪酸有明显的抗氧化作用,其中特丁基对苯二酚抗氧化效果较佳。中国大鲵肌内脂肪富含ω-3和ω-6型...     

野生与池养刀鲚肌肉品质特性及抗氧化性的比较分析

比较研究了野生和池养刀鲚（Coilia nasus）肌肉营养成分组成、质构特性和抗氧化特性。结果显示,野生刀鲚肌肉中水分、羟脯氨酸、胶原蛋白含量以及胶原蛋白/总蛋白比值均显著低于池养型,而脂肪含量则显著提高;两者的蛋白质含量、pH均无显著性差异;池养刀鲚肌肉弹性、硬度、咀嚼度、胶着性相较于野生型呈上升趋势,但无统计学差异。野生刀鲚肌肉中SOD、CAT、T-AOC、MDA、GSH-PX、iNOS、GSH/GSSG均显著高于池养型。表明野生和池养刀鲚营养品质存在差异,建议在人工养殖刀鲚中应该注意饵料的种类和丰度,其养殖模式有待进一步改善。     

Estimation of freezing storage time and quality changes in hake (Merluccius merluccius, L.) by low field NMR

The potential of low field NMR (LF NMR) as a fast monitoring technique to estimate the quality of hake (Merluccius merluccius) frozen stored at -10°C for up to 6months was evaluated. LF NMR clearly detected three populations of water: water strongly bound to macromolecules (T(2b)), trapped water (T(21)) and free water (T(22)). As storage time increased, and concomitant with an increase in the T(22) and a decrease in the T(21) water populations, the water holding capacity (WHC) and apparent viscosity values decreased and the shear strength increased, reflecting the characteristic loss of juiciness and tougher texture developed by hake during frozen storage. Two mathematical models were constructed: a simple regression using the biexponential analysis of the relaxation times (T(21), T(22)) and amplitudes (A(21), A(22)) and a partial least square regression (PLS) of CONTIN analysis. Both models seemed suitable to estimate the quality of the product.     

马鹿亚种间杂交后代背最长肌脂肪酸的分析研究

采用气相色谱技术对马鹿不同亚种间杂交后代——天山马鹿、天青二元杂交马鹿和天青塔三元杂交马鹿背最长肌中的20种脂肪酸进行分析研究,结果表明:三种马鹿背最长肌脂肪酸组成及含量各有特点,但是饱和脂肪酸含量均最高,棕榈酸为主要组成成分。都含有一定量的具有抗癌活性的奇数碳原子脂肪酸,含量分别为:3.73%、7.28%和0.71%,该结果为马鹿肉在功能食品领域的发展提供了理论依据。从营养角度出发,天青二元杂交马鹿肉比天山马鹿和天青塔三元杂交马鹿具有更高的营养价值,可以通过杂交育种来选育营养价值更符合膳食标准的健康马鹿肉品原料。     

Rapid determination of 19 quinolone residues in spiked fish and pig muscle by high-performance liquid chromatography (HPLC) tandem mass spectrometry

A multiresidue method has been developed for the confirmation and quantification of 19 quinolones (enrofloxacin, ciprofloxacin, norfloxacin, ofloxacin, flumequine, oxolinic acid, difloxacin, sarafloxacin, sparfloxacin, danofloxacin, fleroxacin, marbofloxacin, enoxacin, orbifloxacin, pefloxacin, nalidixic acid, pipemidic acid, lomefloxacin and cinoacin) in pig and fish by liquid chromatography-tandem mass spectrometry (LC-MS/MS). The samples were extracted with acetonitrile, analytes separated by LC on a C₁₈ column using 0.1% formic acid–methanol with a linear gradient elution programme, and detected by MS/MS. The linear range was 0.3–50 µg kg^–1 with correlation coefficients (r) more than 0.9956. The limits of detection were 0.1 µg kg^–1. Mean recoveries for each analyte in pig muscle and fish ranged from 75.3% to 96.3% and from 79.7% to 94.2% with relative standard deviations below 10%. The method is fast, safe, sensitive and precise, and can be used simultaneously to analyse residual quinolones.     

酶联免疫方法在牛肉加热终点温度检测中的应用

为保证肉类及肉制品的卫生安全,各国要求加热到一定的加热终点温度。研究通过免疫新西兰白兔获得加热终点温度指示蛋白乳酸脱氢酶的抗体,并建立了牛肌肉加热终点温度酶联免疫检测方法。