冰温结合保鲜剂贮藏对牙鲆鲜度和质构的影响

研究了冰温结合复合配方保鲜剂贮藏技术对褐牙鲆(Paralichthys olivaceus)鲜度和质构特征参数变化的影响,同时与单一冰温贮藏样品的相应变化进行了比较和分析.结果表明:冰温结合保鲜剂贮藏方法能够显著延缓牙鲆鱼肉样品细菌总数、K值、TVB-N和pH值等的增加速度;随着贮藏时间的延长,样品组织结构、破断强度和感官指标等的变化均呈现减缓趋势;与单一冰温贮藏条件的样品相比,冰温结合保鲜剂样品的货架期能有效延长10 d左右,达到最佳保鲜效果.     

微冻贮藏条件下鲈鲜度和质构变化

研究鲈在微冻贮藏条件下组织构造、质地剖面分析(TPA)及流变学特征参数(弹性模量E,应力松弛时间τ,粘性模量η,破断强度)的变化,同时结合鲜度指标、细菌总数、K值、TVB-N、pH值和感官特性判断其在微冻条件下的品质变化特征。结果表明,随着贮藏时间的延长,菌落总数、K值和TVB-N上升,pH值则先下降后上升,且上升速度随温度的升高而加快;组织结构呈现肌原纤维间空隙逐渐增大,方向性增强,构造逐渐断裂崩解的趋势;弹性模量呈上升趋势,破断强度、硬度、弹性、粘聚性、咀嚼性呈下降趋势,而应力松弛时间、粘性模量的变化则不显著。与冷藏样品相比,微冻样品的货架期能够延长20 d,说明微冻条件比冷藏条件能更有效的抑制鲈体内酶活性及微生物的作用,缓解蛋白质分解,延长鲈的贮藏期。     

冻结贮藏条件下鲈鱼鲜度和质构变化

研究冻结贮藏条件下鲈鱼组织构造、质地剖面分析（TPA）及流变学特征参数（弹性模量E，应力松弛时间τ，粘性模量η，破断强度gf）的变化，同时结合鲜度指标（细菌总数，K值，TVB—N，pH值）和感官特性判断其品质变化特征。结果表明：随着冻结时间的延长，鲈样品细菌总数下降，K值和TVB—N上升；组织构造呈现纤维间空隙增大、方向性增强、断裂崩解的趋势；弹性模量呈上升趋势，破断强度、硬度、弹性、粘聚性、咀嚼性均呈下降趋势，应力松弛时间、粘性模量的变化则不显著。与冷藏样品相比，冻结样品具有鲜度高、货架期长的特点。     

冷藏和微冻条件下鲤鱼品质变化的研究

为了了解淡水养殖鲤鱼在冷藏和微冻贮藏条件下的品质变化情况,本研究将经前处理后的鲜活鲤鱼分别贮藏于4℃和-3℃冰箱中,测定了菌落总数(TVC)、挥发性盐基氮(TVB-N)、硫代巴比妥酸值(TBA)以及K值等指标的变化。结果显示:冷藏第12天鲤鱼的菌落总数为5.67 logcfu/g,微冻第40天为5.72 logcfu/g;冷藏第8天时TVB-N值为10.55 mg/100 g,微冻第30天TVB-N值为18.85 mg/100 g;冷藏条件下TBA值在贮藏的第14天为0.52 mg/kg,微冻第40天为1.06 mg/kg,均未超过2.00 mg/kg;冷藏第8天K值为55.96%,微冻第30天K值为53.99%。综合各指标变化,4℃和-3℃贮藏鲤鱼的贮藏期分别为8 d和30d,-3℃的微冻贮藏较4℃贮藏鲤鱼贮藏期延长了2.75倍。     

竹叶抗氧化物浸泡结合乳清分离蛋白涂膜对冷藏富硒虹鳟食用品质的影响

为延长冷藏富硒虹鳟的货架期,实验以3种浓度的竹叶抗氧化物溶液(AOBS,质量浓度分别为0.5%、1.0%和1.5%)分别浸泡富硒虹鳟鱼块,再进行乳清分离蛋白溶液(WPIS)涂膜,(25±1)°C下鼓风吹干表面水后置于4°C冰箱贮藏1、4、7、10和13 d,测定鱼块的pH值、TVB-N值、K值、菌落总数和嗜冷菌数、结合水分含量和水分状态,分析涂膜对冷藏富硒虹鳟鱼块品质的影响。结果显示,随着冷藏时间的延长,鱼块的pH值、TVB-N值、K值、菌落总数和嗜冷菌数显著增加,水分含量显著降低,结合水和不易流动水向自由水迁移。其中,1.0%AOBS+WPIS组的pH值、TVB-N值、K值、菌落总数和嗜冷菌数的增加速率和水分含量的减少速率最慢,结合水与不易流动水的比例最高。1.0%竹叶抗氧化物浸泡结合乳清分离蛋白涂膜,提升了乳清分离蛋白涂膜的保鲜效果,可有效抑制富硒虹鳟冷藏过程中品质的劣变,延长货架期。根据TVB-N值、K值和菌落总数,1.0%AOBS+WPIS组可延长富硒虹鳟货架期3 d。本研究可以为富硒虹鳟的低温贮藏技术提供科学指导。     

鲤鱼片真空包装与盐腌处理在冷藏过程中的品质变化规律研究

为了科学地了解鲤鱼(Cyprinuscarpio)鱼片贮藏过程中的品质变化规律,帮助建立高效的品质控制技术,研究了鲤鱼片生鲜真空包装及1.5%盐腌普通包装在4℃冷藏条件下,挥发性盐基氮(TVB-N)、p H、电导率、汁液损失和K值的变化情况。结果显示,在整个贮藏过程中,TVB-N、电导率、汁液损失和K值均随贮藏时间的延长而上升。其中,真空包装生鲜鲤鱼片的TVB-N在贮藏过程中上升较缓慢,与生鲜鱼片相比,盐腌鱼片的TVB-N在贮藏过程中上升较慢,但汁液损失和电导率明显偏高;真空包装能有效抑制鱼片K值的上升,但盐腌无明显抑制效果;p H在贮藏过程中呈"V"形变化,贮藏后期真空包装和腌制处理均能抑制p H的升高。研究表明,鲤鱼片生鲜真空包装和1.5%盐腌普通包装在冷藏期间均能保持较好的鱼肉品质,具有良好的应用前景。     

冷藏与微冻贮藏过程中鲟鱼肉品质变化

为了比较鲟鱼(Acipenser sinensis)肉在4℃冷藏与?3℃微冻过程中的品质变化，提供一种提高鲟鱼新鲜品质的贮藏方式，通过感官评分、菌落总数(TVC)、pH值、挥发性盐基氮值(TVB-N)、硫代巴比妥酸值(TBA)、质构、挥发性风味物质、水分分布状态与肌纤维微观结构等指标的测定，评价了2种温度贮藏对鲟鱼肉品质的影响。结果显示，随着贮藏时间的延长，2种低温保鲜方式下鲟鱼肉的自由水与结合水的比例、TVB-N、TBA和菌落总数均呈现上升趋势；质构指标硬度和弹性及感官评分均呈降低趋势；观察其微观结构发现，随着贮藏时间的延长，肌纤维之间出现黏连，肌节逐渐由清晰变为模糊，?3℃贮藏后期表现尤为明显。综合各指标的变化规律，确定了4℃冷藏和?3℃微冻条件下，鲟鱼肉的货架期分别为6 d和18 d。与冷藏相比，微冻可较好地保持鲟鱼肉品质，微生物对鲟鱼肉的腐败进程影响较小，而质构指标则是影响贮藏末期感官评分的最主要因素。     

冷藏和微冻条件下长丰鲢鱼片品质变化规律的研究

通过测定长丰鲢（ Changfeng silver carp ）鱼片在冷藏（4℃）和微冻（-3℃）条件下的感官品质、菌落总数（ TAC）、汁液流失率、 pH、电导率（ EC）、挥发性盐基氮（ TVB-N）以及K值等指标的变化,评价两种贮藏条件对长丰鲢鱼片品质的影响。结果表明：长丰鲢鱼片分别在4℃贮藏至第8天和-3℃贮藏至第25天时失去感官食用价值。4℃贮藏第6天菌落总数为6.75 lg cfu/g,-3℃贮藏第20天为5.89 lg cfu/g。 TVB-N值在4℃贮藏至第8天为29.1 mg/100 g,-3℃贮藏至第25天为21.1 mg/100 g。与冷藏相比,微冻贮藏下长丰鲢有较高的汁液流失率。综合各项指标变化,冷藏和微冻贮藏条件下长丰鲢鱼片的货架期分别为6 d和20 d,微冻贮藏较冷藏长丰鲢鱼片贮藏期延长了2.3倍。     

鱼肉酶解物及壳聚糖对鲤鱼涂膜保鲜效果的研究

以感官评分、挥发性盐基氮、菌落总数、K值为指标,研究比较了鱼肉酶解物和壳聚糖为原料的涂膜液对鲤(Cyprinus carpio)(4℃)冷藏过程中品质变化的影响。结果显示:贮藏期间,对照组的感官评分显著低于各涂膜组(P<0.05)。贮藏前8 d,涂膜组能够显著抑制K值的升高(P<0.05)。鱼肉酶解物和壳聚糖涂膜组均能够显著抑制细菌的生长,而贮藏2～6 d内鱼肉酶解物涂膜鲤鱼的菌落总数显著低于壳聚糖涂膜组(P<0.05)。贮藏后期,鱼肉酶解物组能延缓TVB-N值的升高,壳聚糖涂膜组能够显著抑制TVB-N值的升高(P<0.05)。鱼肉酶解物可作为一种新的可食性涂膜材料,用于延长鲤鱼的贮藏期。     

凡纳滨对虾在不同冷藏条件下的品质变化研究

通过感官评估、生化分析及蛋白质指纹图谱比较研究了4 ℃和0 ℃冷藏条件下凡纳滨对虾的品质变化,并对评价指标的有效性进行了分析.试验结果表明,0 ℃冷藏能延缓虾的腐败,比4 ℃更有利于凡纳滨对虾的保藏.虾肌肉的挥发性盐基氮(TVB-N)含量随贮藏时间的延长而增加,但在0 ℃条件下无法准确反映虾的品质变化.K值也随贮藏时间的延长而增加,且与感官评价之间存在良好的相关性,能反映凡纳滨对虾在冷藏初期的品质变化.而肌浆蛋白和肌纤蛋白的指纹图谱则能标记冷藏后期凡纳滨对虾肌肉蛋白发生的降解.     

Effect of Fish Gelatin Coating Enriched with Oregano Essential Oil on the Quality of Refrigerated Rainbow Trout Fillet

ABSTRACT

In the present study, the effect of fish gelatin coating (FG; 4%, w/v) containing oregano (Origanum vulgare L.) essential oil (OEO; 1.2% w/v) on shelf-life extension of rainbow trout (Oncorhynchus mykiss) fillet stored under refrigerated storage (4 ± 1ºC) was investigated. The control and the treated fish samples were analyzed periodically for chemical (pH; total volatile basic nitrogen, TVB-N; peroxide value, PV; thiobarbituric acid, TBA) and microbiological (total viable count, TVC; psychrotrophic count) characteristics. The FG + OEO treatment produced significantly lower (p < 0.05) TVB-N values as compared to control and FG-coated samples after Day 6 and until the end of the storage period. The TBA values remained low and were found to fluctuate during storage. Results showed that TVC exceeded 6 log CFU g^?1 on Day 8 of storage for control and FG-coated samples and Day 12 for samples coated with FG + OEO. The reduction of 1.05 and 0.83 log CFU g^?1 of psychrotrophic counts was achieved by FG + OEO coating in trout fillet (p < 0.05) as compared with control and FG-coated samples, respectively. Therefore, the incorporation of OEO into FG coating may be a promising method of maintaining the storage quality of the rainbow trout fillet stored at refrigerated temperature.     

北极虾在不同冷藏条件下的质量变化与质量指标

采用感官评估、物理、化学、微生物分析方法，对贮藏在不同冷藏条件下的北极虾的质量变化与质量指标进行了研究。保藏方法分别为传统冰块冷却法、液态冰冷却法、盐水-冰混合冷却剂法，贮藏环境温度为-1．5℃或1．5℃。研究结果表明，液态冰冷藏法对延缓虾腐败变质的效果比传统冰块冷藏法、盐水-冰混合冷却剂冷藏法好。经过1d的贮藏后发现，无论在-1．5℃还是1．5℃的环境温度下，保藏在液态冰中虾的挥发性总氮(TVB-N)都有所下降，并且在-1．5℃的环境温度下，其TVB-N值在3d后才回升到刚开始贮藏时的水平，而在其它保藏方法中，虾的TVB-N值始终随贮藏时间的延长而增加；除保藏在液态冰-1．5℃环境中虾的三甲胺(TMA)在贮藏的第1天有所降低以外，其它各试验组虾的TMA值均随贮藏时间的延长而增加。检测结果还表明，保藏在传统冰块及盐水-冰混合冷却剂中虾的细菌总数(TVC)增加最快，其次是保藏在液态冰中1．5℃的环境下。而保藏在液态冰中-1．5℃的环境下，虾的细菌繁殖最慢，并且在贮藏初期，产生了明显的细菌总数降低及细菌繁殖被抑制的现象。采用主要因子分析(PCA)和方差分析(ANOVA)发现，质量指标如TVB-N、TMA、TVC、pH、NH3(电子鼻测量值)和感官评估结果等相互之间存在着良好的相关性。     

The Relationship Between Electric Impedance and Quality Parameters of Ungutted and Gutted Common Carp (Cyprinus carpio) Stored at 4°C

In order to understand the relationship between electric conductivity and quality parameters of common carp during storage, the electric impedances in the frequencies ranging from 1 to 20 kHz, total viable count (TVC), total volatile basic nitrogen (TVB-N), and K values of gutted and ungutted common carp were determined during 4°C storage. The result showed that the change ratio of electric impedance (Q value) of both gutted and ungutted common carp decreased with increasing storage time, while TVC, TVB-N, and K values increased gradually. There was a good correlation between Q values and TVC, TVB-N, and K values of gutted and ungutted common carp, and their correlation coefficients were 0.952, 0.965, 0.928, and 0.956, 0.975, and 0.938, respectively. This result demonstrated that Q value is valid to predict some quality parameters of common carp during 4°C storage.     

Influence of Chitosan Nanocomposite and Rosemary (Rosmarinus officinalis L.) Extract Coating on Quality of Huso huso Fillet Inoculated with Listeria monocytogenes During Refrigerated Storage

This study aimed to evaluate the antilisterial and antioxidative effects of chitosan nanocomposites and rosemary extract coating on the fillet of Huso huso inoculated with Listeria monocytogenes during refrigerated storage (4°C). Fish fillets were subjected as control (without coating), 0.5% rosemary extract (RE), 1% chitosan (CS), and combination of chitosan and rosemary extract as chitosan nanocomposite (CS/RE). Then, samples were inoculated with L. monocytogenes. Subsequently, the chemical parameters (total volatile basic nitrogen (TVB-N), peroxide value (PV), pH, and thiobarbituric acid (TBA)) and antilisterial effects of coatings were monitored during 16 days of storage at 4°C. According to the results, CS/RE demonstrated a significant (p < 0.05) ability to inhibit the growth of L. monocytogenes from 4.14 log cfu/g to 2.23 log cfu/g at the end of the storage period, followed by CT and RET treatments, respectively, compared to the control. Even though samples coated with CS/RE had the lowest pH and TVB-N values (p < 0.05), this coating was not able to pause the protein denaturation after 8 days of storage (p > 0.05) compared to the other treatments. On the other hand, CS/RE coating retarded lipid oxidation by decreasing PV and TBA production in the samples compared to the control up to the end of refrigerated storage (p < 0.05).     

Shelf-Life Extension of Fish Fillets by Spraying with Microbial Transglutaminase

The effect of spraying microbial transglutaminase (MTGase) at various levels (1, 4, 7, and 10 units/gram) on the quality of mackerel (Scomber scombrus) fillets was investigated during refrigerated storage. The results of pH and the total volatile base nitrogen (TVB-N) revealed that 7 µ/g MTGase treatment met the best results regarding fish quality. The oxidation was hindered by increasing MTGase concentration, and the lowest totox value was recorded in the fillets treated with 10 µ MTGase. The progress in the total free amino acids was suppressed with the addition of MTGase, and the most effective concentration was found to be 7 µ/g MTGase treatment. Moreover, this concentration was the most promising in inhibition of the total mesophilic aerobic bacteria, the total psychrophilic aerobic bacteria, coliform, and yeast-mold. Panelists preferred the samples treated with 7 µ/g MTGase in terms of odor, texture, and appearance. The addition of MTGase straightened the fish muscle and helped preserve its initial texture. It is important to use the proper concentration of MTGase instead of high concentrations.     

凡纳滨对虾虾仁在冻藏过程中品质变化研究

以凡纳滨对虾（Penaeus vannamei）为研究对象,经过去头和去壳处理后,于-35℃冷冻过夜,然后置于-18℃条件下进行保藏试验。通过测定解冻损失率和肉色变化,明确冻藏期间虾肉的质量变化规律,结合腺苷三磷酸（ATP）及其降解产物、总挥发性盐基氮（TVB-N）和酸碱度（pH）等鲜度指标的测定结果,分析对虾在冻藏条件下鲜度的变化规律,旨在为其生产加工提供理论依据。研究结果表明,冷冻保藏至第18天时解冻损失率达到最大,同时表面色差（L^＊）也达到最大值41.56。而虾肌肉中的ATP质量摩尔浓度冻藏第1天就降低了71.78%,次黄嘌呤（Hx）和次黄嘌呤核苷（HxR）则一直维持在较低水平。第10天鲜度指标（K值）达到最大值7.18%,并能比较稳定地保持这一水平,结合TVB-N测定结果,发现冻藏至第30天时,虾肌肉中的TVB-N仍未超过腐败临界值。因此,冻藏处理可以保持凡纳滨对虾的鲜度,使各项理化指标维持在较低水平,但会加重解冻损失现象。     

Effect of Chitosan-Gelatin Composite and Bi-Layer Coating Combined with Pomegranate Peel Extract on Quality Properties of Belanger’s Croaker (Johnius Belangerii) Stored in Refrigerator

The aim of this study was to evaluate the effects of chitosan-gelatin coating with two different methods (composite and bi-layer) in combination with pomegranate peel extract (PPE) on the microbiological (mesophilic bacteria, psychrotrophic bacteria, and Enterobacteriaceae) and chemical (total volatile bases-nitrogen (TVB-N), pH, thiobarbituric acid (TBA), and free fatty acid (FFA)) properties of Belanger’s croaker (Johnius belangerii) fillets during refrigerated storage (4 ± 1°C). In this study, composite coating (CC), bilayer coating (BC), CC+PPE, and BC+PPE led to 6.88, 7.00, 6.52, and 6.32 log₁₀ CFU/g reduction in mesophilic bacteria, 6.67, 7.02, 5.35, and 4.21 log₁₀ CFU/g in PTC and 2.99, 2.71, 2.37, and 2.41 log₁₀ CFU/g, compared with control sample for 16 days storage time, respectively. Chitosan-gelatin coating enriched with PPE has retarding effects on spoilage of fish samples, thus extending the shelf life during refrigerated storage. The quality characteristics of croaker treated with chitosan-gelatin coating combined with PPE were better than those treated by chitosan-gelatin coating or PPE alone during the storage, exhibiting that there is a synergistic effect between chitosan-gelatin coating and PPE. The bi-layer coating was better than one composite coating in combination with PPE in reducing lipid oxidation of fillets.     

Effects of Natural and Artificial Colorants on Hot Smoked Garfish—Belone belone (Linnaeus, 1761)—Stored at 4 ± 1ºC

In this study, the effects of natural and artificial colorants on the shelf life of hot smoked garfish were investigated in terms of its chemical, microbiological, and sensory quality. Turmeric and Sunset Yellow FCF were used as the natural and artificial colorants, respectively. The amount of total volatile basic nitrogen (TVB-N) and thiobarbituric acid (TBA), counts of total mesophilic aerobic bacteria, total psychrophilic aerobic bacteria, total yeast and molds increased during the storage (p < 0.05). The results showed that turmeric and Sunset Yellow FCF had a significant effect on pH value and salt content of hot smoked garfish samples during storage (p < 0.05). According to the sensory analysis results, the shelf life of hot smoked garfish stored at 4 ± 1ºC was determined as 17 days.     

Effects of Modified Atmospheric Packaging Conditions on the Quality Changes of Pasteurized Oyster (Crassostrea belcheri) Meat during Chilled Storage

ABSTRACT

The effects of different atmospheric conditions on the quality and the shelf life of pasteurized oyster meat in chilled storage were investigated. The alternatives tested for pasteurized oyster meat were normal air (Control), 75% CO₂/25% N₂ (MAP-1), 75% CO₂/25% O₂ (MAP-2), 75% CO₂/5% O₂/20% N₂ (MAP-3), and vacuum packing (VP). The various observations of microbiological (total viable count (TVC), Enterobacteriaceae, Pseudomonas spp., lactic acid bacteria (LAB), and hydrogen sulfide–producing bacteria), physical (color coordinates L*, a*, and b*, and cutting strength), chemical (moisture, pH, total volatile basic nitrogen (TVB-N), peroxide value (PV), and thiobarbituric acid reactive substances (TBARS)) and sensory properties were performed every 3 days over a total of 27 days. During storage across all the treatments, L*, a*, cutting strength, pH, moisture content, and sensory scores decreased; whereas, b*, TVB-N, PV, TBARS, and microorganisms increased. However, among the various alternatives, MAP-1 had the best retention of oyster quality during storage. Based on sensory and microbiological qualities, the shelf lives in chilled storage were 9 days for control, 15 days for VP, 21 days for MAP-2 and MAP-3, and 24 days for MAP-1-treated cases.