【作者】 王亮；

【导师】 曾名湧；

【作者基本信息】 中国海洋大学 ， 水产品加工及贮藏， 2010， 硕士

【摘要】 本课题主要针对我国生鲜水产品物流中存在的瓶颈问题,以凡纳滨对虾为原料,着重解决凡纳滨对虾鲜度下降快、贮藏期短、物流半径小等技术难题,旨在为凡纳滨对虾冰温气调保鲜技术体系的建立提供理论依据和技术支撑。本论文的研究内容包括以下5个部分：1.凡纳滨对虾冰温贮藏下品质特性的评价以基本营养成分分析和描述性分析为基础,并结合生化分析及仪器检测,研究凡纳滨对虾品质特性的变化,通过因子与距离相关分析,建立冰温贮藏条件下凡纳滨对虾的食用品质评价体系。结果表明：随着贮藏时间的延长,凡纳滨对虾的基本营养成分、感官、质构、色差以及生化指标均存在显著性差异(P<0.05)。经因子分析及距离相关分析发现,得到的9组因子在置信度95%的范围内,营养成分因子Fn、质构因子Ft、色差因子Fc,以及生化因子Fb之间都呈现出较显著的相关性(P<0.05),而描述性分析因子Fd与质构因子Ft、色差因子Fc相关性不显著(P>0.05),因此在一定程度上还不能完全用描述性分析来代替仪器检测和理化分析,三者必须有机结合才能更全面地反映凡纳滨对虾在冰温贮藏过程中的品质变化。2.凡纳滨对虾低温相变区间热特性的研究为了提供海水虾类的热特性参数并获得有效降低海水虾类冰点的复合调节剂,本研究以凡纳滨对虾为研究对象,采用D-饱和最优设计,探讨甘氨酸、氯化钠以及山梨糖醇等调节剂对凡纳滨对虾冻结点(Freezing point)、不可冻结含水率(Unfreezable water mass fraction,α)、表观比热(Apparent specific heat, Capp)以及热焓(Enthalpy, H)等热特性参数的影响,并结合构造函数法优化了凡纳滨对虾Tf,α,Capp以及H。结果表明,影响Tf主次顺序是山梨糖醇、甘氨酸和氯化钠(均极显著)含量,影响α主次顺序依次是甘氨酸、氯化钠(均极显著)和山梨糖醇含量(显著),影响Capp主次顺序是氯化钠(极显著)、甘氨酸和山梨糖醇含量(显著),影响H主次顺序依次是甘氨酸、氯化钠和山梨糖醇含量(均极显著)。随着甘氨酸、氯化钠和山梨糖醇含量的增加,凡纳滨对虾的α增大,冻结及熔融相变区间、Tf均向低温方向偏移,相应地,Capp和H也随着调节剂含量的增加而减小。凡纳滨对虾在0.8761%甘氨酸、2.2983%氯化钠及0.5887%山梨糖醇的配比下,对应响应值分别为Tf,-17.4402℃；α,17.2223％;Capp,41.0379 J/g℃；H, 155.9419J/g。3.混料设计优化凡纳滨对虾气调配比的研究采用3因子3质点单纯形混料设计,研究冰温贮藏条件下不同气调包装的凡纳滨对虾品质特性的变化(气体：原料=3:1),通过嗜温菌、嗜冷菌、感官、汁液流失率、pH以及TVB-N指标的分析,最终确定凡纳滨对虾冰温贮藏下最佳的气调配比,同时通过最小二乘法回归对各变量进行了显著性分析。结果表明,随着CO2水平的增加,凡纳滨对虾中嗜温菌、嗜冷菌以及TVB-N值会明显受到抑制(P<0.05),但其汁液流失率也会相应地增加；而增加N2浓度,结果则恰恰相反。另外,高浓度的O2会加速凡纳滨对虾的褐变,但适量该气体则有利于其气味的改善。总之,通过优化设计,凡纳滨对虾的各项响应变量(气味、外观、TVB-N、pH、汁液流失率、嗜温菌及嗜冷菌)均达到了最佳,最终获得加权后的最佳气体配比,74.2%CO2/9.7%O2/16.1%N2(为了符合工业化操作,实际设定气体配比为75%CO2/10%O2/15%N2)。4.不同包装方式的凡纳滨对虾冰温贮藏过程中微生物、生化及感官特性的变化规律探讨了四种包装方式(空气AP、真空VP、气调包装MAP1,40%CO2/30%O2/30%/N2；气调包装MAP2,75%CO2/10%O2/15%/N2)的凡纳滨对虾在冰温贮藏过程中腐败微生物、生化及感官特性的变化规律。结果表明,与AP组相比,VP、MAP1以及MAP2组能够显著抑制凡纳滨对虾中嗜温菌和嗜冷菌的生长(P<0.05)。菌相分析表明,气单胞菌为AP组的优势腐败菌,而该菌在VP、MAP1和MAP2组中均得到了显著抑制(P<0.05)。VP组和MAP组(MAP1和MAP2)的优势腐败菌分别为乳酸菌和肠杆菌。并且在贮藏过程中,假单胞菌最终也成为AP、VP和MAP1组腐败期的优势菌属。生化分析表明,所有样品组的pH值均呈现出相似的变化规律。与AP组比较,VP、MAP1和MAP2组均显著地抑制了TVB-N值的增加,另外在气调包装中,提升CO2水平会明显增加凡纳滨对虾的汁液流失率。结合感官分析发现,AP组、VP组、MAP1组及MAP2组的货架期分别达到4天、7天、9天、11-12天。5.凡纳滨对虾抑菌剂的筛选及最佳配比的优化以10种抑菌剂(氯化钠、乙二胺四乙酸、甘氨酸、4-乙基间苯二酚、植酸、山梨酸钾、茶多酚、乳酸链球菌素、壳聚糖、溶菌酶)初步筛选的结果为基点,采用抑菌圈实验确定所选抑菌剂的使用浓度,并通过3因子2次通用旋转设计确定各种单一防腐抑菌剂的最佳配比用量。结果表明,茶多酚、乳酸链球菌素、壳聚糖和溶菌酶都能明显抑制混合腐败菌的生长。其中,茶多酚和壳聚糖对所选的气单胞、假单胞、乳酸菌以及肠杆菌菌株都有明显的抑制效果,抑菌谱较广；而溶菌酶和乳酸链球菌素对乳酸菌菌株有抑制作用,抑菌谱较窄,相对于溶菌酶来说,乳酸链球菌素不仅价格低廉,且在低pH条件下具有良好的稳定性。通过3因子(X1—茶多酚,X2—壳聚糖,X3—乳酸链球菌素)2次通用旋转设计得到复配抑菌剂的预测模型：Y=97.59591-11.05664X1-16.78799X2-7.22909X3-4.69267X12-6.4 6044X22-3.63201X32+4.12500X1X2+3.37500X1X3+3.87500X2X3,其中,X1和X2之间以及X2和X3之间的交互效应显著(P<0.05),而X1和X3之间的交互效应不显著(P>0.05)。单因子抑菌效果依次为X2＞X1＞X3,最终通过频率分析法得到复配抑菌剂的最优浓度范围,并在95%的置信区间内,得到经济效益较好,并贴近于实际工业化生产的抑菌剂配比方案：X1为0.30g/L,X2为1.00g/L,X3为0.60g/L。对此方案进行实验验证得到菌落总数均下降了4个对数单位。更多还原

【Abstract】 Based on the disadvantage of fresh-keeping logistics, in the paper, the main problems including quick drop of the freshness, short shelf life and small radius of logistics system were investigated. The final object of the study was to provide the theory and essential technique for the preservation and modified atmosphere packaging system of white shrimp (Litopenaeus vannamei) under controlled freezing-point storage.This study includes five parts of content as follows:1. Evaluation on quality of white shrimp (Litopenaeus vannamei) under controlled freezing-point storageNutritional components and descriptive analysis were integrated to investigate quality changes of white shrimp samples by the way of secondary instrumental measurement and biochemical analysis methods under controlled freezing-point storage, then the shrimp quality determination system was set up by factor analysis and distances correlation analysis of data. Results indicated that there were significant difference(P<0.05) in the nutritional components, trained panel assessment, texture, color and biochemical measurement, respectively. Moreover, nine factors were obtained by distances correlation analysis, it was concluded that most of factors, such as nutrition components factor, color factor, biochemical factor and so on, had significant correlations(P<0.05), whereas indistinctive correlations were found among descriptive factor, texture factor and color factor(P>0.05). Consequently, descriptive analysis could not replace the instrumental measurement methods. On the contrary, the three ones should be integrated to reflect the changes of quality in white shrimp (Litopenaeus vannamei) during controlled freezing-point storage.2. Thermophysical properties evolution of white shrimp (Litopenaeus vannamei) meat during phase transitionIn order to provide available thermophysical property parameters and obtain optimum freezing-point regulators for fresh-keeping of marine shrimp, initial freezing point(Tf), the unfreezable water mass fraction(a), apparent specific heat(Capp), enthalpy(H) of white shrimp (Litopenaeus vannamei) and effects of GLY, NaCl and Sorbitol content on thermophysical properties of white shrimp (Litopenaeus vannamei) during phase transition were studied by differential scanning calorimetry (DSC) and D-saturated optimum design. Results indicated that the effect of compound regulators on four response factors(Tf, a, Capp and H) was as follows:Tf, Sorbitol>GLY>NaCl(P < 0.01);α,GLY>NaCl(P<0.01)>Sorbitol(P<0.05); Capp, NaCl(P<0.01)>GLY >Sorbitol (P<0.05); H, GLY>NaCl>Sorbitol(P<0.01). As the content of compound regulators increased, the thawing phase transition range of white shrimp meat shifted to the lower temperature range, and the content,of unfreezable water increased, while the initial freezing point decreased linearly, and both of latent heat and the peak value of apparent specific heat decreased. The initial freezing point, the content of unfreezable water, the latent heat and the peak value of apparent specific heat were-17.4402℃,17.2223%,41.0379J/g and 155.9419J/(g℃) under the ratio of 0.8.761% for GLY,2.2938% for NaCl and 0.5887% for Sorbitol, respectively.3. Study on the optimized modified atmosphere for packaging of white shrimp (Litopenaeus vannamei) by mixture designThe optimal initial gas composition to maintain quality of modified atmosphere (MA) packaged white shrimp (Litopenaeus vannamei) under controlled freezing-point storage was determined through microbiological analyses, sensory evaluation of raw odour and appearance, exudates, pH and TVB-N analyses. White shrimp packaged under gas to product ratio of 3:1 and gas mixtures according to a simplex centroid mixture design spanning the whole area from 0 to 100mL/100mL and in between mixes of all the three major packaging gases, CO2, O2 and N2 were analysed after 2,4 and 6 days of storage, moreover the correlation among all variables was analyzed by partial least squares (PLS-2) regression. Mesophilic and psychrotrophic plate count decreased and amount of exudates increased with increasing CO2 concentration, while mesophilic, psychrotrophic plate count and values of total volatile basic nitrogen (TVB-N) increased with elevating N2 levels. Odour and appearance decreased in the white shrimp with decreasing CO2 and O2 levels. However, high O2 concentration could accelerate the browning of white shrimp. On the contrary, suitable O2 was beneficial to maintain the odour of white shrimp. The weighted optimum gas mixture for MA packaging of white shrimp was determined to be 74.2mL/100mL CO2,9.7 mL/100mL O2 and 16.1mL/100mL N2.4. Effects of various packaging conditions on microbiological, biochemical and sensory attributes of white shrimp (Litopenaeus vannamei) during controlled freezing-point storageEffects of vacuum and modified atmosphere packaging (MAP) on bacterial flora, pH, total volatile basic nitrogen (TVB-N), exudates and sensory attributes in white shrimp (Litopenaeus vannamei) during controlled freezing-point storage were investigated. The results indicated vacuum, MAP1 (40%CO2/30%O2/30%N2) and MAP2 (75%CO2/10%O2/15%N2) samples were more effective for inhibiting growth of total mesophilic bacteria, Aeromonas spp. and psychrotrophic bacteria compared to air package (AP) (P<0.05). During the storage period, Pseudomonas spp. dominated final spoilage organisms of white shrimp in AP, VP and MAP1, and Lactic acid bacteria (LAB) and Enterobacteriaceae became also dominated spoilage organisms stored under VP and MAP2, respectively. The pH value of various packaging samples showed the similar changes during storage. However, pH values of AP samples were significantly (P<0.05) higher than those of VP and MAP package. The TVB-N content of the samples stored under AP exceeded the upper threshold of 30mg N/100g shrimp muscle on the 5th day after storage. VP, MAP1 and MAP2 treatment significantly inhibited the increase of TVB-N (P<0.05). Formation of exudates (EX) under AP, VP, MAP1 and MAP2 increased during the storage, and the value was higher with the increase of CO2 levels in the packaging (MAP1 and MAP2). Sensory analyses (odor and appearance attributes) indicated that a shelf-life of ca.4 days for AP,7 days for VP, 9 days for MAP1 and 11-12 days for the optimum MA-packaged white shrimp samples stored at controlled freezing-point temperature, respectively.5. Study on the preliminary screening and optimization of inhibitors for white shrimp (Litopenaeus vannamei)Based on the preliminary screening of inhibitors and bacteriostatic ring, the optimal proportion of inhibitors to prolong the shelf life of white shrimp (Litopenaeus vannamei) under controlled freezing-point storage was determined through microbiological analyses. Microbiological changes of white shrimp in the putrefactive time and different proportion of inhibitors according to a quadratic general rotary design were analyzed. Results demonstrated that tea polyphenol (TP), nisin(NI), chitosan(CHI) and lysozyme(LY) could notably inhibited the growth of spoilage organisms, Furthermore, TP and CHI had significant inhibition on Pseudomonas spp., Aeromonas spp., Lactic acid bacteria and Enterobacteriaceae, while LY and NI had no effect on other spoilage organisms but Lactic acid bacteria. Secondary relationship under three factors (X1—TP, X2—CHI, X3—NI) quadratic general rotary design was figured to be Y=97.59591-11.05664X1-16.78799X2-7.22909X3-4.69267X12-6.46044X22-3.63201X32+4.12500X1X2+3.37500X1X3+3.87500X2X3,There were obvious interactions between X1 and X2, X2 and X3 (P<0.05), but no obvious interactions between X1 and X3(P>0.05). The effect on inhibiting microbiology was X2>X1>X3. By means of frequency response analysis, the optimal proportion of inhibitors was determined to be 0.30g/L for X1, 1.00g/L for X2 and 0.60g/L for X3.更多还原