The effects of rosemary extract combination with vacuum packing on the quality changes of Atlantic mackerel fish burgers

The effects of the use of antioxidant technology on the quality of mackerel burgers stored at 4 °C were investigated in terms of sensory, biochemical [thiobarbituric acid (TBA), total volatile basic nitrogen (TVB‐N), peroxide value (PV) and free fatty acids (FFA)] and microbiological analyses [total viable count (TVC)]. Fish meat was divided into three groups; the control (C) without rosemary extract, the second group with 0.4% rosemary extracts (Group A) and the third with 0.8% rosemary extracts (Group B). Results showed that the TVB‐N level did not exceed acceptability limit (30–35 mg 100 g^?1) for all groups. TBA value for the control significantly increased from 1.47 to 4.80 MA kg^?1 whereas it slightly increased in treatment groups as the storage time increased. Significantly higher PV and FFA (P < 0.05) were obtained from the control group. Rosemary extract, in combination with vacuum pack was effective in controlling the growth of bacteria and biochemical indices.     

基于视觉图像的鲅鱼新鲜程度的检测方法

鲅鱼新鲜程度是评价其质量好坏的重要因素。为提高鲅鱼检测新鲜程度准确性,研究基于视觉图像的鲅鱼新鲜程度的检测方法。研究对象是某地海鲜市场中的30条鲅鱼,通过鲅鱼视觉图像采集系统采集鲅鱼视觉图像,利用区域填充算法及形态学开运算对采用大津法分割的鱼体二值图像进行填充及去噪,融合上山法与区域生长方法分割鱼眼区域,通过全局动态阈值分割方法分割鱼鳃图像;提取图像特征时,利用图像的R、G、I分量灰度均值提取鱼体、鱼眼及鱼鳃图像颜色特征,采用G分量提取鱼眼中心区域面积。将图像特征输入到NeuroShell 2神经网络判别模型中,实现鲅鱼新鲜程度的有效检测。经实验验证,该方法检测鲅鱼新鲜程度的准确率平均高达98.28%,依据鱼眼中心区域面积+颜色灰度均值特征进行鲅鱼新鲜程度检测的准确率最高,且检测不同死亡时间的鲅鱼新鲜度的检测准确率高达95%,说明鲅鱼新鲜度的检测为海鲜检测提供了理论基础。     

鲭鱼生物胺生成菌的分离与鉴定

从鲭鱼体内分离7 株生物胺产生菌,其中3 株菌可以产生色胺,4 株菌可以产生2-苯乙胺,4 株菌可以产生腐胺,1 株菌可以产生尸胺,3 株菌可以产生组胺,1 株菌可以产生酪胺。组胺生成量较高的No.1菌株形态学、生理生化分析及菌种鉴定结果表明该菌株极有可能为侵肺巴斯德氏菌,可信度为99.9%。     

Effect of Combining Proteolysis and Lactic Acid Bacterial Fermentation on the Characteristics of Minced Mackerel

ABSTRACT: To improve the quality of fish muscle, mackerel muscle protein was hydrolyzed by proteases from Aspergillus oryzae , and then fermented by lactic acid bacteria (LAB). The highest protease activities were obtained from A. oryzae after 72 h incubation at 25°C. Acidic protease activity was much higher than neutral and alkaline proteases. SDS-PAGE indicated the degradation of muscle proteins after 1 or 2 h hydrolysis by A. oryzae proteases at 50°C. During 48 h fermentation by Pediococcus pentosaceus L and S at 37°C, rapid growth of LAB, decline in pH, and suppression in the growth of microflora, Enterobacteriaceae, Staphylococcus , and Pseudomonas , occurred while increases in whiteness, nonprotein nitrogen, sensory quality, and free amino acids were observed. These data suggested that the acceptability of LAB -fermented mackerel hydrolysates could be substantially improved.     

Comparison of Gelation Mechanism of Surimi between Heat and Pressure Treatment by Using Rheological and NMR Relaxation Measurements

ABSTRACT: The stress-relaxation and nuclear magnetic resonance (NMR) proton spin-spin relaxation time (¹H T₂) measurements were performed to elucidate the gelation mechanism of heated and pressurized surimi gels. Numerical inverse Laplace transformation of the stress-relaxation data showedlarge distributions of stress-relaxation times and the Kohlrauch-Williams-Watts (KWW) equation described well the stress-relaxation process for each gel. NMR measurement gave information about the content of the exposed protein surface. From these results it is considered that the heat treatment induces the denaturation and re-aggregation of protein, which contribute to the formation of strong network structure. On the other hand, the pressure treatment contributes to the formation of weak cross-links made by the aggregation of protein in native form.     

A novel compound, 7,10-dihydroxy-8(E)-octadecenoic acid from oleic acid by bioconversion

Sixty-two cultures from the Agricultural Research Service (ARS) Culture Collection and 10 cultures isolated from soil and water samples in Illinois were screened for their ability to convert agricultural oils to value-added industrial chemicals. A new compound, 7,10-dihydroxy-8(E)-octadecenoic acid (DOD), was produced from oleic acid at a yield of greater than 60% by bacterial strain PR3 which was isolated from a water sample in Morton, IL. To our knowledge, DOD has not been previously reported. The optimum time, pH and temperature for the production of DOD were 2 days, 7.0, and 30°C, respectively. The production of DOD is unique in that it involves hydroxylation at two positions and rearrangement of the double bond of the substrate molecule.     

鲭鱼在中餐的运用探讨

本文阐述了鲭鱼的种类、营养、功用,同时探讨了利用传统中式烹调技法结合西餐菜肴风格,烹制出具有外形美观、色泽丰富、香味浓郁、营养时尚等特点的鲭鱼特色菜肴。     

Production of eicosapentaenoic acid by a bacterium isolated from mackerel intestines

Optimization of culture conditions for the growth rate, 5,8,11,14,17-cis-Eicosapentaenoic acid (EPA) content and EPA productivity of a bacterium isolated from Pacific mackerel intestines was investigated by use of a culture medium containing 1.00 wt% peptone and 0.50 wt% yeast extract in an artificial sea water (ASW). Cultivation temperature affected the growth rate and cellular EPA content of the bacterium. The cellular EPA content at 8°C was as great as 16.8 mg/g of dry cells, which was more than two times greater than that at 25°C (7.3 mg/g of dry cells), although the growth rate showed a maximum at 25°C. Both the yield of bacterial cells and the cellular EPA content at 25°C reached maximum values when the pH of the culture medium was nearly 7.0 and when the concentration of ASW was 100% (v/v). Under optimum culture conditions [25°C pH 7.0 and 100% (v/v) ASW], the amount of EPA accumulated in the cellular lipids reached 45.6 mg/L of culture broth after 8 hr.