真空预冷结合减压贮藏保鲜水蜜桃

对无锡水蜜桃进行了不同过程的真空顸冷后，进行三阶段减压贮藏保鲜试验，同时以不顸冷直接进行三阶段减压贮藏和常压冷藏为对照试验，结果表明，在减压条件下水蜜桃真空顸冷的效果不明显，其各项生理生化变化与不预冷直接进行三阶段减压贮藏无明显差异，而三阶段减压贮藏则明显优于常压冷藏。     

常压和真空浓缩鸡汤的微冻贮藏特性

以4 ℃冷藏为对照,研究常压和真空浓缩处理后在－5.5 ℃微冻期间鸡汤贮藏特性的变化。结果表明：贮藏100 d,常压浓缩鸡汤的菌落总数增长几乎为零,而真空浓缩鸡汤菌落总数分别在微冻50 d、冷藏30 d后逐渐增加;常压浓缩鸡汤的亮度值（L*）下降幅度显著小于真空浓缩鸡汤（P＜0.05）,挥发性盐基氮（total volatile basic nitrogen,TVB-N）含量和硫代巴比妥酸反应物（thiobarbituric acid reactive substances,TBARs）值变化幅度均小于真空浓缩鸡汤;常压浓缩鸡汤电泳条带变化没有真空浓缩明显。2 种浓缩鸡汤在微冻贮藏期间的TVB-N含量和TBARs值显著低于冷藏期间（P＜0.05）;微冻真空浓缩鸡汤L*显著高于冷藏真空浓缩鸡汤（P＜0.05）;同时2种微冻浓缩鸡汤的电泳条带颜色较冷藏浓缩鸡汤深。说明常压浓缩和微冻贮藏有利于维持鸡汤色泽、抑制微生物繁殖以及减缓蛋白氧化和脂肪氧化。     

真空条件对黄金梨减压储藏效果的影响

为探讨不同减压贮藏条件对黄金梨保鲜效果的影响,以MAP贮藏为对照试验,分别探讨黄金梨在20～30 kPa、40～50 kPa、70～80 kPa 3个真空压力范围内减压贮藏对梨果实生理生化变化的影响。结果表明:不同真空压力组均可在不同程度上降低梨果实贮藏期间呼吸强度、抑制VC含量和果实硬度的下降,而果实失重率与对照组相比差异不显著(P>0.05),其中真空压力为20～30 kPa时,梨果实的贮藏效果明显优于其它两种压力组。     

减压处理对水蜜桃保鲜效果的影响

以"湖景"水蜜桃为材料,常压冷藏处理为对照,研究1.5k Pa((3±1)℃)减压处理20d和减压预处理12、24h后常压冷藏至20d,再置于常压(25±1)℃中5d对水蜜桃品质变化的影响。结果表明:在(3±1)℃低温下,贮藏20d后,减压处理20d组效果最为显著(p0.05),失重率和相对电导率最低,呼吸受到抑制,VC和可滴定酸下降缓慢,货架期最长5d以上。同时,12h减压预处理对提高水蜜桃保鲜品质的效果略好于24h减压预处理,都显著(p0.05)优于常压对照。减压处理及减压预处理都具有良好的保鲜效果,而减压预处理能极大节约成本,更利于推广应用。     

减压冷藏对芒果贮藏品质的影响

以台农一号芒果为试验材料,研究了减压条件对其采后贮藏品质的影响。结果表明:减压冷藏技术能够有效地减缓果实中可滴定酸、VC以及可溶性固形物含量的降低,且保持了芒果的硬度,对其黄化以及膜透性的增加具有良好的抑制作用。其中,10,20 kPa下芒果的贮藏品质明显优于30kPa的;10kPa下的芒果可以保持较低的转黄指数和较高的硬度;20kPa下的芒果能更好地维持VC、有机酸等营养物质。实际生产中,兼顾贮藏效果和贮藏成本,选择20kPa的压力较为适宜。     

三阶段负压贮藏条件下钙处理调控绿芦笋的衰老

将采后绿芦笋分别放入质量分数为0.5%、1.0%、1.5%、2.0%的氯化钙(CaClz)溶液,浸泡处理10 min,以蒸馏水浸泡10 rain为对照,然后进行温度为24～4℃,相对湿度为85%～95%,真空压力(绝对压力)入库前3 d控制在10℃20 kPa,其后7 d控制在20～30 kPa,以后保持在35～50 kPa的"高-中-低,,三阶段负压贮藏.研究了4种不同质量分数的CaClM2处理对绿芦笋衰老效应的调控作用.结果表明,用适当质量分数的钙处理可显著降低绿芦笋的呼吸强度、乙烯释放量、MDA含量、相对电导率及衰老指数,提高绿芦笋的抗坏血酸含量、叶绿素含量及商品率;但对降低木质素含量效果不显著.其中钙处理以1.5%的CaCl2效果最佳.     

低温减压贮藏对“川中岛”水蜜桃保鲜效果的影响

研究了不同减压贮藏条件(10、50和90 kPa)对"川中岛"水蜜桃在(4±0.5)℃下贮藏的影响。结果表明:减压贮藏能有效地延缓水蜜桃果实品质下降。其中,经50 kPa处理贮藏效果较好,经其处理的果实褐变程度较低,并明显延缓水蜜桃后熟速率,保持了较高的硬度,与常压对照相比,失重率降低了40.00%,腐烂指数减少了87.50%,保持了水蜜桃较佳的感官品质,对保持水蜜桃色泽、香气、味道有显著效果。     

不同冷却方式对低温熟制猪肉品质的影响

以低温（80 ℃）熟制的猪肉为研究对象,采用冷藏冷却（4 ℃）、冷冻冷却（?18 ℃）和真空冷藏冷却（4 ℃）3种方式将其从80 ℃冷却至10 ℃,研究冷却速率、质量损失率、质构特性、色泽以及硫代巴比妥酸值（TBA）等品质变化,并研究其在4 ℃下贮藏期间的TBA值及气味等品质变化情况。结果表明:真空冷藏冷却和冷冻冷却的冷却速率显著高于冷藏冷却（P<0.05）;冷藏冷却质量损失最大（6.67%）（P<0.05）,冷冻冷却质量损失最少（4.47%）;真空冷藏冷却具有最小的L*值,a*值和最大的b*值（P<0.05）;冷藏冷却处理具有最大的硬度值（13647.14±51.47 g）（P<0.05）;真空冷藏冷却的样品气味较其他两组处理的气味差别大;在冷却结束和贮藏过程中冷藏冷却处理组的TBA值均显著高于其他两组（P<0.05）;随着贮藏时间的增加,3组样品的气味差异变大。冷冻冷却和真空冷藏冷却均能生产较好品质的低温猪肉制品,且具有较好的贮藏品质。     

超高压对冷藏带鱼段的保鲜效果

研究了超高压预处理对4℃冷藏带鱼段保鲜效果的影响。试验以4℃冷藏带鱼段做对照,设置不同压力和保压时间(220 MPa、290 MPa,3、6、9 min)对带鱼进行超高压预处理后4℃贮藏,共7个试验组,每隔1天测定感官评定、菌落总数(TPC)、持水力(WHC)、挥发性盐基氮(TVB-N)、三甲胺氮(TMA-N)和硫代巴比妥酸(TBA)等指标。结果表明:超高压能有效抑制菌落的增殖,压力越高,保压时间越长,抑制作用越明显。冷藏组带鱼的货架期为4 d,220 MPa组的货架期延长至10 d,290 MPa组的货架期延长至12 d。随着压力的增大、保压时间的延长,超高压处理后鱼肉的透明度减少,持水力有所降低,但能有效抑制TMA-N的增长速度,并在一定程度上抑制带鱼的脂肪氧化。新鲜带鱼超高压处理后的TVB-N会随着压力的增大有所增加,在贮藏过程中,冷藏组的TVB-N的增长速度逐渐超过超高压组,且保压时间越长、压力越大,抑制TVB-N作用越好。其中290 MPa、6min超高压处理组,290 MPa、9 min超高压处理组保鲜效果最好,贮藏12 d时,带鱼的细菌总数分别为6.19、6.04 lg(CFU/g),TVB-N分别为19.87、20.86 mg N/100 g,基本都处在带鱼二级鲜度之内。     

微真空贮藏对西兰花采后品质的影响

为探讨微真空贮藏条件对果蔬的保鲜效果,以西兰花为试验材料,研究了贮藏温度为(3±0.5)℃、真空压力为66.7 kPa～80.0 kPa的微真空贮藏条件下西兰花采后品质的变化。结果表明:与相同温度下的常压贮藏相比,微真空贮藏能显著(P<0.05)降低西兰花花球的失重率和可滴定酸含量的下降,延缓西兰花花球中VC、可溶性蛋白质的降解及游离氨基酸的生成量,抑制叶绿素分解及花球色差的变化。表明微真空贮藏条件能显著(P<0.05)提高西兰花的采后保鲜品质。     

不同压力条件对平菇减压贮藏效果的影响

为探讨不同压力条件对平菇减压贮藏效果的影响,以MAP贮藏为对照,分别探讨了30-40 kPa、50-60 kPa、70-80 kPa三种压力条件对平菇生理生化变化的影响。结果表明:不同压力条件均可在不同程度上抑制平菇的呼吸强度,减缓可溶性蛋白质的降解,降低褐变度的升高及细胞膜相对电导率的增大,而失重率与CK组差异不显著(P>0.05)。其中,在50-60 kPa压力条件下平菇的保鲜效果最佳,显著优于30-40 kPa和70-80 kPa两种压力条件(P<0.05),最佳压力条件下的失重率、褐变度等指标分别如何?。     

不同冷链贮运条件下冷鲜鸭肉品质变化

为研究不同冷链贮运条件对冷鲜鸭肉品质变化的影响,通过模拟产品冷链贮运过程中的环境,以感官评定、菌落总数和挥发性盐基氮(total volatile base-nitrogen,TVB-N)值为评定标准,研究了不同包装方式、运输时长、运输温度及运输途中的振动强度对冷鲜鸭肉品质的影响。结果显示,气调包装(53%O2+47%CO2)在贮运末期的TVB-N值仅为12.78 mg/100 g,仍处于二级鲜度,比真空包装和气调包装更能维持冷鲜鸭肉原有品质;运输1 h组在整个实验过程中感官评分值下降较慢,在实验末期其感官评分仍在8分以上;运输温度对产品贮运后期的菌落总数有显著影响(p<0.05),低温(4℃)运输能够有效地保持产品品质,比高温运输延长1~2 d贮藏期;振动强度对产品菌落总数有显著影响(p<0.05),3 Hz振幅对鸭肉品质影响较小,在贮藏末期菌落总数为5.04 lg CFU/g,TVB-N值为11.01 mg/100 g。本研究为冷鲜鸭肉冷链运输条件的选择提供了参考。     

竹叶抗氧化物结合不同包装方式对鲜罗非鱼片保鲜效果的影响

以感官特性、菌落总数、汁液流失率、pH值、挥发性盐基氮(total volatile basic nitrogen,TVB-N)值及硫代巴比妥酸(2-thiobarbituric acid,TBA)值为评价指标,研究竹叶抗氧化物结合不同包装方式对鲜罗非鱼片保鲜效果的影响。结果表明,竹叶抗氧化物对鲜罗非鱼片具有良好的抗菌和抗氧化作用,0.1 g/100 m L竹叶抗氧化物处理的罗非鱼片比对照组货架期延长了4~6 d;竹叶抗氧化物结合真空包装或气调包装均能够明显抑制微生物生长繁殖,降低TVB-N值和TBA值,减缓感官品质的下降速率,延长货架期;冰藏条件下各组鲜度指标均明显优于冷藏条件,冰藏条件下0.1 g/100 m L竹叶抗氧化物结合真空包装或气调包装处理的罗非鱼片保鲜效果提高明显,货架期增加至18 d。研究表明,竹叶抗氧化物结合真空包装或气调包装在鲜罗非鱼片保鲜方面具有应用的潜力。     

Recent advances in pressure modification-based preservation technologies applied to fresh fruits and vegetables

Fresh fruits and vegetables are important parts of the human diet. The consumer demand for fruits and vegetables is increasing due to their rich nutritional value, appealing taste, and healthy perception. However, due to their highly perishable nature, appropriate preservation technologies must be developed to meet the consumer’s demand for healthy, additive-free, microbiologically safe, and high quality fresh fruits and vegetables. The preservation technologies based on modification or control of pressure alters the normal atmospheric pressure of the preservation environment. The materials to be preserved are subjected to either very high or low pressure to extend their shelf life. The mechanism, advantages, and limitations of pressure modification-based preservation methods such as high hydrostatic pressure, hyperbaric treatment, vacuum cooling, hypobaric storage, and vacuum packaging focusing on their applicability to fresh fruits and vegetables have been reviewed. This review suggests that these technologies have potential to extend the shelf life and achieve a better preservation of the quality of fresh fruits and vegetables.     

Development of volatile fraction of fresh cut osmotically treated mango during cold storage

The influence of minimal processing by osmotic treatment and cold storage on the volatile profile of mango was studied by comparison with the volatile profile of fresh samples. Osmotic treatments, at atmospheric pressure and by applying a vacuum pulse, were carried out using a 45 Brix sucrose solution with (2%) and without calcium lactate, at 30 °C. Samples were treated until they reached 20 Brix in all cases. The volatile profile of the samples was characterised at 0, 1, 4 and 8 days of cold storage at 10 °C, using purge and trap thermal desorption and GC–MS. Osmotic treatment provokes a decrease in the terpene concentration (the most abundant compounds in the volatile fraction mango) and an increase in ethyl acetate and 1-butanol. This fact was especially observed in treatment applying vacuum impregnation with calcium. Treatment at atmospheric pressure, with calcium in the osmotic solution, was the best way to prevent aroma alterations during processing and to ensure its stability throughout cold storage.     

The effect of controlled atmosphere storage on pickle production from pickling cucumbers cv. ‘Troy’

Fresh pickling cucumbers (cv. Troy) were stored for 30 days at 7°C and 90–95% relative humidity (RH) under different controlled atmosphere (CA) combinations, and samples taken at 0 (i.e., without storage), 10, 20 and 30 days of storage were processed to sweet pickle. At each sampling, physical and chemical analyses were carried out in the fresh pickling cucumbers to determine the changes in the quality with storage time. Besides, physical, chemical and sensory analyses were carried out in the pickles elaborated from the fresh samples taken at the same periods, after keeping at room temperature for 6 months, with the aim of determining CA and storage time effect on the final pickle quality. It was found that storage of cucumbers to be processed to pickle could be possible for less than 10 days at 7°C temperature and 90–95 RH under normal atmosphere (NA). However, physical and chemical analyses showed that storage period of fresh pickling cucumbers could be prolonged up to 30 days under the same storage conditions, if suitable atmosphere combinations are created. Nevertheless, it was concluded that restricting the storage period of fresh pickling cucumbers to 20 days could give better results after processing to pickle. An erratum to this article can be found at     

气调包装对冷鲜羊肉保鲜效果的影响研究

研究了单组分气体及不同比例气体组分对鲜羊肉进行气调包装后,对贮藏期间影响品质因素的关键技术指标的影响。试验条件下最优气体配比为CO2比例为20%,O2比例为65%。在此配比条件下,既可以改善并维持冷鲜羊肉良好的鲜红色泽,也可以在贮藏期间保持鲜肉的pH值和TVB-N值在规定的范围内,对延长冷鲜羊肉的贮藏期和保持良好的品质起到了一定作用。     

Influence of different preservation treatments on the volatile fraction of desalted cod

In the present study, desalted cod underwent a water blanching treatment and the incorporation of additives (citric acid and potassium sorbate), combined with different types of packaging (air, vacuum and modified atmosphere), to achieve an improvement of the shelf life of ready-to-use desalted cod. The purpose of this work was to evaluate the effect of these combined methods of preservation on the volatile fraction of desalted cod during 42 days in cold storage. The volatile compounds identified in all samples were those mainly related to fresh odor in whitefish, although with some exceptions. Untreated desalted cod showed a high increase of 3-methyl-1-butanol (described as a microbial spoilage index) during the storage period; a higher increase in air packaging than in vacuum and modified atmosphere packaging. The slow increase of this compound, as well as the evolution of ketones and aldehydes observed for the rest of the samples submitted to treatment, demonstrated the effectiveness of the combined treatments applied. The most efficient treatment was the combination of additives together with modified atmosphere packaging.