金针菇多糖对微冻大黄鱼及其鱼片品质变化的影响

为研究金针菇多糖（polysaccharide from Flammulina velutipes，FVP）对微冻大黄鱼及鱼片在贮藏期间肌原纤维蛋白性质的变化及水分分布的影响，实验分别选用0.03、0.06、0.09 g/L FVP浸渍处理大黄鱼和鱼片，以无菌水处理为对照组，分析微冻贮藏期间样品的感官指标得分、总挥发性盐基氮含量、总巯基含量、Ca2＋-ATPase活性、蛋白流变学性质以及水分迁移变化规律。结果表明：FVP可有效抑制整鱼总挥发性盐基氮含量上升和感官得分的下降；减缓整鱼及鱼片在微冻过程中总巯基含量、Ca2＋-ATPase活性下降和水分流失；此外FVP还能够延缓大黄鱼因腐败而出现的蛋白凝胶能力减弱。在本实验选取的多糖浓度范围内，0.09 g/L FVP处理组保鲜效果较强。该研究结果可为FVP用于水产品贮运保鲜提供理论参考。     

北朝时期绞缬女绢衣的研究与复制

以中国丝绸博物馆馆藏的1件北朝时期绞缬女绢衣为对象进行了研究与复制。选择电力纺作为复制服饰用面料,采用纹样间的上下间距为1. 4 cm、左右间距为1 cm、捆扎圈数为2圈的绞缬工艺实现了鱼子缬纹样效果;以五倍子为染料、Fe³⁺为媒染剂的手工天然染色方法还原了复制对象的颜色并推断为近深咖色;利用鱼子缬花版,采用顺接式和对称式2种纹样定位方式,使鱼子缬纹样与服装版型相配合,达到了鱼子缬女绢衣完整复原的效果。北朝绞缬女绢衣的复制,为今后此件服饰的深入研究提供理论与实物参考。     

Effect of temperature and salt on thermal inactivation of Listeria monocytogenes in salmon roe

Listeria monocytogenes is a potentially fatal foodborne pathogen that can be found in ready-to-eat seafood products, such as fresh salmon roe. Once contaminated, salmon roe must be decontaminated prior to human consumption. This study was conducted to determine the thermal inactivation kinetics of L. monocytogenes in raw salmon roe as affected by bacterial strain, temperature, and salt concentration. Three different strains of L. monocytogenes, including serotype 4b (F2365), 1/2b (F4260), and 1/2a (V7), were individually inoculated to salmon roe supplemented with salt (0–4.5%), and heated under different temperatures (57.5–65.0 °C) to evaluate the survival of the bacterium during heating and determine the D-values. Results showed that the thermal resistance (log D) of L. monocytogenes was significantly affected by bacterial strain, temperature, and salt and by their interactive effects, with strain F2365 being the most heat-resistant among all three strains tested. Salt added to salmon roe significantly increased the thermal resistance of the bacteria. For L. monocytogenes F2365, the z value of the bacterium in salmon roe was 5.99 °C, and its heat resistance increased with the level of salt in a linear manner. The results of kinetic analysis and the models obtained in this study may be used by the seafood industry to develop proper thermal processes to eliminate L. monocytogenes in raw salmon roe and to ensure microbial safety and prevent foodborne illness.     

岱瞿族大黄鱼质构特性与感官评价的相关性分析

目的 分析养殖大黄鱼质构特性与感官评价的相关性。方法 选择温州不同海域的养殖大黄鱼样品进行肥满度、蛋白质、脂肪、水分、胶原蛋白测定,并进行感官评定和质构剖面分析(textureprofileanalysis,TPA);对结果进行因子和主成分分析,以及相关性分析;再以TPA指标为自变量、感官评价指标为因变量进行逐步回归分析,建立感官预测模型。结果 温州不同海域养殖大黄鱼,在肥满度、脂肪含量、蛋白质含量、质构测定中弹性与咀嚼性指标均存在显著性差异,感官评价指标也存在显著性差异。通过主成分分析得到TPA指标和感官评价指标各1个主成分,累计方差贡献率分别为72.86%和89.97%。相关性结果表明,感官评价结果与TPA测定结果之间存在显著的相关性(r=-0.933～0.808,P<0.05),并建立了色泽、滋味、肉纤维和质地与咀嚼性的预测模型和气味与弹性的预测模型。结论 本研究确定了温州地区养殖大黄鱼品质评价定量指标;大黄鱼感官评价指标受TPA指标中的弹性、咀嚼性影响;本研究的温州大黄鱼感官评价预测模型为大黄鱼品质评价标准体系的科学建立提供了依据。     

基于近红外光谱的大黄鱼新鲜度评价模型

目的 探索定量评价大黄鱼新鲜度的方法。方法 在整鱼背部采集近红外光谱, 将原始光谱预处理后分别与挥发性盐基氮(TVB-N)、菌落总数建立偏最小二乘(PLS)模型、区间偏最小二乘(iPLS)模型、向后区间偏最小二乘(biPLS)模型和联合区间偏最小二乘(siPLS)模型。结果 biPLS模型的精度最高、预测性能最佳。TVB-N的biPLS模型的校正集和预测集相关系数分别为0.8371和0.7652; 菌落总数的biPLS模型的校正集和预测集相关系数分别为0.878和0.7009。结论 大黄鱼的近红外光谱信息与其TVB-N、菌落总数间都存在较高的相关性, 所建模型可以快速、无损地定量评价大黄鱼的新鲜度。     

大黄鱼鱼卵脂质含量及脂肪酸组成分析

用氯仿-甲醇法提取大黄鱼鱼卵的粗脂肪,经甲酯化处理,用气相色谱法对其脂肪酸的组成进行分析。结果显示大黄鱼鱼卵湿基总脂肪含量达19.6%,干基总脂肪含量达44%,磷脂占总脂肪比例为61.2%,胆固醇占总脂肪比例为3.2%,而且大黄鱼鱼卵还含有丰富的ω-3PUFA多不饱和脂肪酸,其EPA和DHA之和达到了25.5%。     

大黄鱼卵分离蛋白的凝胶特性分析

本文以大黄鱼卵盐溶蛋白为原料,在85℃加热20 min后于室温下放置12 h制备大黄鱼卵分离蛋白凝胶,并对其凝胶特性进行分析,同时探究了pH对大黄鱼卵分离蛋白凝胶特性的影响.结果显示,大黄鱼卵分离蛋白成胶的最低浓度为100 mg/mL,且在pH8条件下的制备的大黄鱼卵分离蛋白凝胶具有更好的流变特性.低场核磁和扫描电镜的...     

超高压处理对养殖大黄鱼肉蛋白质特性的影响

目的研究超高压处理对养殖大黄鱼肉蛋白质特性的影响。方法超高压处理养殖大黄鱼肉后,通过双缩脲法、十二烷基硫酸钠-聚丙烯酰氨凝胶电泳(sodium dodecyl sulfate-polyacrylamide gel electrophoresis,SDS-PAGE)、差示扫描量热法(differential scanning calorimetry,DSC)及蛋白质巯基含量及持水性分析,研究超高压对养殖大黄鱼肉品质的影响。结果压强对不同类型溶解性的蛋白含量有较大影响。350 MPa 10 min时水溶性蛋白含量最高,达到74.12 mg/g;300 MPa 25 min时酸溶性蛋白含量最高,达到14.53 mg/g。可见超高压处理显著改变了养殖大黄鱼不同溶解性、不同结构蛋白的含量(P0.05);提高了养殖大黄鱼蛋白质的热稳定性;增加了蛋白质的巯基含量;降低了蛋白质的持水能力。结论超高压处理使养殖大黄鱼肉蛋白质的持水性降低,溶解性、巯基含量及热稳定性增加,并使蛋白质结构发生改变。     

不同预冻条件对小黄鱼品质的影响

本文以小黄鱼为原料,采用-4.3℃的微冻保鲜和三种不同的低温冷冻处理(-80℃低温冰箱速冻至-18℃、-80℃低温冰箱速冻至-60℃、液氮速冻至-60℃,然后均于-18℃条件下贮藏),研究了小黄鱼的p H值、TVBN值、Ca2+-ATPase活性、TBA值、感官评分、总巯基和盐溶性蛋白含量在一个月内的变化,探究不同的预冻处理对小黄鱼品质的影响。结果表明,随着贮藏时间的延长,四组样品的p H值都呈现出下降的趋势,而微冻组随后表现出回升的趋势,TVBN和TBA值随贮藏时间的延长逐渐升高,在第30 d时,四组样品的TVBN值分别达到14.26 mg/100 g、7.11 mg/100 g、6.13 mg/100 g、5.53 mg/100 g;盐溶性蛋白含量分别为17.68 mg/g、28.36 mg/g、30.01 mg/g、32.33 mg/g;四组样品的Ca2+-ATPase活性、总巯基含量、感官评分也随贮藏时间的延长逐渐下降。这表明不同的预冻条件对小黄鱼贮藏过程中的品质以及风味有不同程度的影响。     

Liquid chromatographic quantification of synthetic colorants in fish roe and caviar

According to the directive 94/36/EC of the European Union (EU), quantities of synthetic colorants added to foods are restricted by upper limits and, therefore, reliable methods for their quantification have to be established. Approved colorants, defined by so-called E numbers, are permitted for dying fish roe (commonly named caviar). We developed a chromatographic method for the quantitation of colorants in roe. The recovery rates of 14 synthetic food colorants from solid materials (Al₂O₃, XAD-2, anion exchangers, and polyamide-6) were tested, and polyamide powder was selected as adsorbent for quantitative determination of colorants in fish roe. The most effective sample preparation comprises extraction of colorants from roe with 1 M aqueous ammonia, defatting of the solution with n-hexane, adjustment of pH 2 of the extract, adsorption of dyes on the polyamide and desorption with a mixture of aqueous ammonia (25%) and methanol (1:9 v/v). The isolated colorants were analyzed by RP-HPLC with diode-array detection. In several caviars, the maximum of individual colorants regulated by EU were exceeded or colorants declared on food labels were not detected. Presented at 25th International Symposium on Chromatography, Paris, France, October 4–8, 2004.