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Emerging techniques for assisting and accelerating food freezing processes: A review of recent research progresses 总被引:1,自引:0,他引:1
Freezing plays an important role in food preservation and the emergence of rapid freezing technologies can be highly beneficial to the food industry. This paper reviews some novel food freezing technologies, including high-pressure freezing (HPF), ultrasound-assisted freezing (UAF), electrically disturbed freezing (EF) and magnetically disturbed freezing (MF), microwave-assisted freezing (MWF), and osmo-dehydro-freezing (ODF). HPF and UAF can initiate ice nucleation rapidly, leading to uniform distribution of ice crystals and the control of their size and shape. Specifically, the former is focused on increasing the degree of supercooling, whereas the latter aims to decrease it. Direct current electric freezing (DC-EF) and alternating current electric freezing (AC-EF) exhibit different effects on ice nucleation. DC-EF can promote ice nucleation and AC-EF has the opposite effect. Furthermore, ODF has been successfully used for freezing various vegetables and fruit. MWF cannot control the nucleation temperature, but can decrease supercooling degree, thus decreasing the size of ice crystals. The heat and mass transfer processes during ODF have been investigated experimentally and modeled mathematically. More studies should be carried out to understand the effects of these technologies on food freezing process. 相似文献
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本文研究不同冰点调节剂对西兰花冰点的影响。实验选取葡萄糖、维生素C、氯化钙和山梨醇四种冰点调节剂,利用单因素比较实验法,系统研究了冰点调节剂种类及其使用条件对西兰花冰点的影响。结果表明,氯化钙是较好的冰点调节剂;3%氯化钙浸泡30rain对西兰花的冰点调节效果较好,使西兰花冰点从-0.8℃降到.1℃。 相似文献
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板栗冻结规律及速冻加工技术研究 总被引:2,自引:0,他引:2
通过测定板栗在不同冻结温度的冻结曲线探讨板栗冻结规律 ,并通过酶活性检测、色差分析和感官评价 ,探讨冻结前热烫、添加抑制剂处理等措施对速冻板栗色、香、味保持的影响。试验结果表明 ,板栗冻结过程与一般的果蔬冻结过程有所不同 ,冻结过程 3个阶段不明显 ,只有初阶段和中阶段。其冻结点温度为 - 2 8℃ ,而最大冰晶生成带为 - 2 8~ - 1 5℃ ,与通常果蔬的 - 1~- 5℃不同。板栗含水分少、淀粉多 ,对冷冻适应能力强 ,适合冻结与冻藏 ,只要加工处理适当 ,就可以保持较好品质。影响速冻板栗产品质量的主要因素是酶活性 ,其次是包装。冻结前浸渍糖液及其他添加剂处理对速冻板栗色泽、风味影响不明显。除了酶褐变和非酶褐变 ,表层色素物质受破坏也是导致栗仁褐变的重要原因 相似文献
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为了研究不同速冻方式和冻结温度对鲍鱼冻结过程中的品质影响程度、产生原因及机理,本文以鲜活鲍鱼为研究对象,对比采用2种速冻方法(空气速冻和液体速冻)、3种冻结温度(-20℃、-40℃、-60℃)进行冷冻,以蛋白质冷冻变性程度、肌肉组织结构和弹性作为理化和质构特性评价指标。试验结果表明:液体速冻的冻结速率始终比空气速冻高10倍左右,盐溶性蛋白溶解度下降率低2%左右,Ca2+-ATPase活性下降速度与Mg2+-ATPase活性上升速度均略缓慢,蛋白质变性程度低,解冻后鲍鱼肌肉组织间空隙小,弹性好;冻结过程中,冻结温度越低,冻结速率越快,盐溶性蛋白损失越少,蛋白质变性程度和解冻后的弹性无明显变化;综合考虑冻结速率、品质、能耗等因素,认为液体速冻是适合鲍鱼的速冻方法,-60℃液体速冻是相对最佳的速冻工艺。 相似文献
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研究超声波功率、超声波作用时间、超声波脉冲值对提高毛豆仁浸渍冷冻速率的影响.通过响应面分析可知在载冷剂温度为-20℃下超声波辅助浸渍冷冻的最佳工艺参数:超声波功率为58 W,超声波作用模式为50%,超声波作用时间为0.7 min,解冻后毛豆仁质构(硬度)和持水力分别为6.05 kg/cm~2和92%. 相似文献
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Freezing point depression (FPD) measurement can be used as a fast means of determining solute concentration of an aqueous solution in the laboratory and the data are useful in the process design of low temperature operations, e.g. freeze concentration and freeze drying, etc. It is desirable to have a cost-effective device for FPD measurement. Here, we describe a simple device for highly concentrated aqueous solutions. The characteristics of the freezing process of a small amount liquid (a few micro-liters) in this device, i.e. the effects of sample size, supercooling and location of measuring point, have been investigated. The reproducibility of the method has been found to be within ± 4% in a wide range of freezing points (−10 °C to 0 °C) for NaCl solutions. The solid entrainment in the ice formed prior to the freezing point being reached has also been estimated, and gives a distribution coefficient of 0.5. 相似文献
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采用真空制冷技术冷冻鲜羊肉的研究 总被引:1,自引:0,他引:1
真空制冷技术是目前降温速度最快的一门制冷技术。它是一种理想的冷却和冻结方法,它能使蔬菜、果品和鲜花等农产品以及肉类,烘焙类食品在真空状态下快速,均匀冷却甚至冻结,使产品的质量,鲜度和营养价值得到保证。因此,该技术已在众多食品处理加工领域得到了广泛的应用,而且已经成为发达国家果蔬入市前必须进行的标准化作业之一。本文在介绍真空制冷的机理的同时以鲜羊肉为原料进行了真空冻结试验并对试验过程进行分析。 相似文献
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Effect of freezing time on the quality of Indian mackerel (Rastrelliger kanagurta) during frozen storage 总被引:1,自引:0,他引:1
Lakshmisha IP Ravishankar CN Ninan G Mohan CO Gopal TK 《Journal of food science》2008,73(7):S345-S353
The present study aims to find the effect of freezing methods on the quality of mackerel (Rastrelliger kanagurta) in commercial plate and air blast freezers during freezing and subsequent frozen storage (-18 degrees C). Total time for freezing was significantly different (P < 0.05) between the plate and air blast freezers (90 and 220 min, respectively). This difference in the freezing time could be attributed to the varied quality of the 2 samples. Upon freezing, the moisture content decreased in air blast frozen samples compared to plate freezer where protein content decreased in both the samples. Upon freezing and during frozen storage, lipid oxidation products (peroxide value, thiobarbutiric acid value, and free fatty acid value) and volatile bases (total volatile base nitrogen and trimethyl amine nitrogen) showed an increasing trend in both the samples with values slightly higher in air blast frozen samples compared to plate frozen samples. The total plate counts showed a significantly (P < 0.05) decreasing trend in both the samples. K value did not show any significant (P < 0.05) difference between the samples where as the histamine formation was significantly (P < 0.05) increased in air blast frozen samples compared to plate frozen samples. The taste and overall acceptability was significantly different (P < 0.05) in plate frozen samples compared to air blast frozen samples on 3rd month. Both samples were in acceptable condition up to 3 mo but the plate frozen samples quality was slightly better than the air blast frozen samples. 相似文献
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冷冻熟面的工艺技术研究 总被引:9,自引:0,他引:9
冷冻熟面是一种高品质的方便面,可以长期冷冻保存,又具有新鲜面条的口感。研究了冷冻熟面的生产工艺、技术参数及面条配方,对冷冻熟面的品质指标作了探讨。 相似文献
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Main meat freezing theories,including transition theory,glass transformation theory and ice crystallization theory,were introduced.Some novel freezing technologies such as high pressure freezing,ultrasonic freezing,ice nucleus bacteria freezing protein,cell alive system freezing and decompression freezing were also generally reviewed. 相似文献
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为了提高沙光鱼冻藏期间的品质,采用静止空气冻结、送风冻结、液氮速冻处理新鲜沙光鱼,研究不同冻结方式对沙光鱼品质的影响。以蒸煮损失率、挥发性盐基氮(TVB-N)、硫代巴比妥酸值(TBA)、K值、盐溶性蛋白含量、Ca2+-ATP酶活性为理化指标并结合冰晶观察和感官评价,考察沙光鱼冻藏过程的品质变化。结果表明:静止空气冻结、送风冻结和液氮速冻通过最大冰晶生成带的时间分别为315、95、8.5 min,液氮速冻耗时最短(P<0.05)。与其它两种冻结方式相比,液氮速冻的机械损伤较小形成的冰晶细小且分布均匀。在冻藏过程中蒸煮损失率、TVB-N值、TBA值、K值均呈上升趋势,液氮速冻上升速率显著低于静止空气冻结和送风冻结。盐溶性蛋白含量、Ca2+-ATP酶活性、感官评分均呈下降趋势,静止空气冻结下降最快,液氮速冻下降最慢。冻藏180 d时,液氮速冻沙光鱼的TVB-N值为13.15 mg/100 g、K值为19.78%,达到一级鲜度的标准,送风冻结为二级鲜度,静止空气冻结已不宜食用。液氮速冻能更好地抑制蛋白质冷冻变性、脂肪氧化和微生物的作用,较好地维持沙光鱼的鲜度。因此,液氮速冻优于送风冻结和静止空气冻结,保鲜效果最佳,能更好地保持沙光鱼的品质。 相似文献
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Main meat freezing theories, including transition theory, glass transformation theory and ice crystallization theory, were introduced. Some novel freezing technologies such as high pressure freezing, ultrasonic freezing, ice nucleus bacteria freezing protein, cell alive system freezing and decompression freezing were also generally reviewed. 相似文献
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MOHAMMED SHAFIUR RAHMAN ROBERT H. DRISCOLL 《International Journal of Food Science & Technology》1994,29(1):51-61
The equilibrium freezing points of fresh invertebrate seafoods measured by the freezing curve method varied from −0.5 to −2.07°C. the freezing point of seafood was modelled by empirical and semi-empirical correlations, and by theoretical equations derived from the Clausius-Clapeyron equation and Raoult's law. Useful prediction were only obtained within species. 相似文献