解冻方式对牦牛乳品质的影响

牦牛乳营养丰富，由于泌乳期较短人们常用冻藏的方式贮存，但是不同解冻方式对牦牛乳的品质有一定的影响。本研究观察不同解冻方式（4℃冷藏解冻、室温静水解冻、40℃水浴解冻、微波解冻）下-20℃和-40℃冻藏乳的品质差异。结果显示，静水解冻的冻结乳pH较低，菌落总数最多，在微生物的作用下营养成分含量也最低；冷藏解冻的冻结乳脂肪聚集程度最明显，稳定性最差；由于微波温度较高，使得微波解冻下牦牛乳的脂肪氧化度和蛋白水解度较高，营养成分含量偏低。相比较而言，40℃水浴解冻后乳的稳定性较高，解冻时间快，营养成分损失较少。此外，-40℃冻藏乳的蛋白和脂肪含量显著大于-20℃冻藏乳，提示冻结速率越快解冻时对乳品质的影响越小。     

解冻方式对冻结鸡汤流变与蛋白质的影响

探究解冻方式(微波、高温水浴、室温空气解冻)对冻结鸡汤(-20,-40℃冻结)流变与蛋白质的影响。结果表明:冻结鸡汤解冻后汤体具有假塑性;相同剪切速率条件下,-20℃冻结鸡汤室温空气解冻后黏度和剪切应力均大于-40℃冻结鸡汤,但微波、高温水浴解冻后的黏度和剪切应力趋势线几乎完全重合,且均低于室温空气解冻组。同一冻结鸡汤室温空气解冻后的胶原蛋白含量、可溶性蛋白含量、巯基含量和乳化活性均显著高于其他解冻方式(P0.05),但羰基含量显著低于其他解冻方式(P0.05)。因此,不同解冻方式的冻结鸡汤流变和蛋白质变化较大,且微波、高温水浴解冻对冻结鸡汤的影响比室温空气解冻更大。     

不同冻结和解冻方式对猪肉品质的影响

为探究冻结和解冻方式对猪肉品质的影响,以解冻汁液流失率,p H,脂类氧化(TBARS)值,蛋白质溶解度,滋味及微观结构的变化作为猪肉品质的评定指标。采用-18、-27、-70℃三种冻结温度进行冻结,冻结后-18℃冻藏3 d,每个冻结组解冻时均分别采用4℃低温空气、25℃静水、25℃空气三种方式进行解冻。结果表明:冻结方式与解冻方式对猪肉品质均有不同程度的影响。通过多因素方差分析可以得出,解冻汁液流失、蛋白质溶解度同时受冻结、解冻方式影响显著(p0.05)。p H受冻结、解冻方式影响不显著(p0.05);TBARS受解冻方式影响显著(p0.05),受冻结方式影响不显著(p0.05);解冻方式是影响滋味变化主要因素;-70℃冻结和4℃低温解冻能够较好地保持猪肉品质。     

不同冻结温度对菠萝丁质量的影响

目的研究不同冻结温度对菠萝丁质量的影响。方法将菠萝丁分别放在-20℃、-25℃、-30℃下冻结，研究速冻前后菠萝细胞结构、质构和汁液流失率的变化。结果不同冻结温度下，细胞破坏程度不同，-30℃下速冻对细胞结构的破坏较小，解冻后产品不仅硬度损失小，而且汁液流失少。结论-30℃速冻可作为冻结菠萝果丁的适宜温度。     

速冻方式与温度对鲍鱼品质的影响

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。     

冷冻猪肉欧姆加热解冻电势梯度与尺寸对解冻效果的影响

欧姆加热解冻是一种潜力很大的解冻方法。试验中研究冻结物料的尺寸、电势梯度对解冻时间、解冻速率、失水率、解冻均匀性和能量利用率的影响。选用尺寸不同的冻猪肉进行了解冻试验,尺寸分别为直径3、4、5 cm,长度为6 cm。解冻时从中心温度-18～5℃。试验过程中,变换解冻材料中的电势梯度,分别为20、30、40V/cm。结果表明:电势梯度和尺寸对解冻均匀性、失水率、能量利用率的影响不大。电势梯度和样品尺寸对解冻时间的影响较明显,电势梯度变大,解冻时间变小,尺寸增大,解冻时间变长。电势梯度和尺寸对解冻速率的影响分为两个阶段。电势梯度和尺寸对内部冻结温度以下的解冻速率影响不明显。在内部冻结温度以上,电势梯度增大,解冻速率变大,解冻加快,样品尺寸变大,解冻速率降低。欧姆加热解冻较传统解冻中的水解冻具有很大的优势。     

冻结和解冻过程对水产品品质的影响

冻结是水产品保鲜的一种有效的方法,冻结后的水产品一般会进行冻藏。影响冻品质量的因素很多,主要有冻结速率、冻藏温度、解冻速率、冻藏中温度波动、冻结-解冻循环次数等。本文在简要介绍食品的冻结解冻方法的基础上,综述了冻结解冻过程对水产品物理、化学特性的影响。     

不同冻结方式对手抓羊肉微观结构、水分迁移及品质的影响

以共晶点作为冻结终温，研究不同冻结方式(-18，-40，-80 ℃)对手抓羊肉色泽、解冻损失率、水分含量、嫩度、质构特性、水分迁移以及微观结构的影响。结果表明:不同冻结方式相比较，-80 ℃冻结样品的L*值显著低于-40 ℃与-18 ℃冻结样品，且具有最低的解冻损失率(0.20 ± 0.00)和最高的水分含量(0.49 ± 0.01)。冻结速率高时，剪切力值(508.16 ± 50.03)、硬度值(1 422.05 ± 111.63)、咀嚼性(782.32 ± 37.90)、水分横向弛豫时间T21和T22、自由水占比M22(11.30 ± 0.04)较低，内聚性(0.69 ± 0.03)、弹性(0.52 ± 0.03)、回复性(0.24 ± 0.00)、不易流动水占比M21(83.62 ± 0.15)较高，微观结构破坏程度较小，-80 ℃冻结手抓羊肉以上指标最接近未经冻结的手抓羊肉。结论:较高的冻结速率能降低手抓羊肉的解冻损失率，使肉中保有更高的水分和肌原纤维完整性，减少冻融引起的品质下降，维持肉制品质构和嫩度，有利于手抓羊肉品质保持，且以共晶点作为冻结终温，冻结过程历时较短，可为工业化生产过程成本控制提供指导，为手抓羊肉的冷加工提供一定的数据支持。     

不同冻结温度对菠萝丁质量的影响

目的研究不同冻结温度对菠萝丁质量的影响。方法将菠萝丁分别放在-20℃、-25℃、-30℃下冻结,研究速冻前后菠萝细胞结构、质构和汁液流失率的变化。结果不同冻结温度下,细胞破坏程度不同,-30℃下速冻对细胞结构的破坏较小,解冻后产品不仅硬度损失小,而且汁液流失少。结论-30℃速冻可作为冻结菠萝果丁的适宜温度。     

不同解冻方式对小黄鱼品质的影响

采用5种不同的解冻方式(静水解冻、流水解冻、微波解冻、低温空气解冻、超声波解冻)对普通冻结和液体浸渍快速冻结处理的小黄鱼进行解冻,对解冻时间、色泽、质构、丙二醛含量、总巯基含量等指标进行测定比较,并测定解冻后鱼肉的硬度、咀嚼性等质构指标。结果表明:5种解冻方式中微波解冻速率最快,低温空气解冻速率最慢。对于快速冻结和普通冻结处理的小黄鱼,超声波解冻能够有效维持解冻后鱼肉的品质。     

蛋白质水解度测定方法综述

对目前国内外常用的蛋白质水解度测定方法进行了综述，其中pH—state方法是通过滴定水解过程中释放的质子测定DH；OPA、TNBS及国内常用的水合茚三酮和甲醛等测定方法是利用游离氨基的反应测定DH。     

SEROLOGIC IDENTIFICATION OF SPECIES OF ORIGIN OF SAUSAGE MEATS

SUMMARY: A partially purified immunoglobulin G (lgG) solution prepared from the serum of species to be tested was heated to the specifications for sausages. The resulting supernatant fluid was decanted and the precipitate washed with saline and used to immunize rabbits. The supernatant fluid was used to sensitize tanned sheep red blood cells. The immune serum was rendered monospecific by absorptions with heterologous, heated lgG precipitates. A sample of monospecific immune serum was absorbed with a washed homogenate of sausage. Aliquots of the monospecific immune serum, both untreated and sausage absorbed, were tested with cells sensitized with the homologous heated lgG supematant fluid. A significant reduction of titer by sausage absorption indicated that the sausages contained the meat homologous to the immune serum.     

BASIS OF STABILITY OF AMINE SALTS OF LINOLEIC ACID

SUMMARY— The mechanism and generality of the known stabilization against autoxidation conferred on linoleic acid by certain basic amino acids, such as lysine and arginine, was investigated. Basic amino acids were the only class of compounds found to confer the effect. However, the smallest basic amino acid, 2,3-diaminopropionic acid, was not effective, nor was αβω-diaminc acid, 3,6-diaminohexanoic acid, although a simple isomer of lysine. The stabilization was observed only in the solid phase. Inclusion of sodium chloride in the solid matrix was deleterious to the effect. A large number of physical and chemical observations were made and correlated but it has not been possible to draw detailed conclusions about the mechanism of stabilization, nor can a detailed structure of the stabilized complex be suggested. The cause of the phenomenon appears to be closely associated with the physical arrangement of the ions in the crystal lattice.     

百年风尚

一场流光溢彩、赏心悦目的展览,一段百年风尚演进的传奇旅程,一次东西方文化艺术的完美对话。2013年9月13日,“博萃臻艺一中西方珍宝艺术展”在辽宁省博物馆举行了隆重的开幕仪式,法兰西共和国驻华大使白林女士、辽宁省文物局局长丁辉先生、辽宁省博物馆馆长马宝杰先生、卡地亚全球总裁兼首席执行官邓阁仕先生、卡地亚区域行政总裁（北亚洲）陆慧全先生、卡地亚中国区首席执行官陆意斯先生、辽宁省文物店总经理张春鹰先生,以及众多文化界与文博界的贵宾齐聚一堂,共同见证了这场文化艺术盛事。     

聚多元羧酸盐的合成及应用

研究了聚多元羧酸盐的合成方法及反应机理,将其应用于洗涤剂和PVC制品中分别代替三聚磷酸钠和邻苯二甲酸二丁酯,证明有良好效果。     

DEVELOPMENT OF CHAINS OF CELLS OF SACCHAROMYCES CEREVISIAE DURING FERMENTATION

The lengths of chains of cells of Saccharomyces cerevisiae were studied during fermentation. Pitching yeast generally contained about half of the total number of cells as two-celled chains. The chain lengths varied during the subsequent fermentation and the variations were characteristic of the strain. Electronic counting assessments of chain length were unreliable.     

STABILITY OF AQUEOUS EMULSIONS OF THE ESSENTIAL OIL OF HOPS

Hop oil emulsions prepared from different varieties of hops have been found to exhibit enhanced physical stability on the addition of blends of the emulsifiers Span 20/Tween 80 or Span 60/Tween 60. Examination of the particle size and volume distributions of an emulsion by use of a Coulter Counter was found to be an excellent method of monitoring its stability. An indication as to the relative efficiency of emulsifiers can be obtained from Coulter Counter measurements on hop oil emulsions after storage for 4 days. The use of an ultracentrifuge provies a rapid means of testing emulsion stability and hence the effectiveness of emulsion stabilizers.     

EFFECTS OF TYPES OF FAT AND OF RATES AND TEMPERATURES OF COMMINUTION ON DISPERSION OF LIPIDS IN FRANKFURTERS

ABSTRACT— The effect of time, temperature and rpm of comminution of emulsions was determined on the dispersion of approximately 25% of beef fat, pork fat or cottonseed oil in frankfurters. The numbers of lipid particles 5 μ or less in diameter increased in frankfurters containing either beef or pork fat as comminution was continued to higher temperatures, with pork fat dispersed more thoroughly. Fat tended to separate from frankfurters containing beef fat in particles 200 μ or more in diameter. In contrast, no specific degree of dispersion of particles 5 μ or less in diameter consistently indicated emulsion stability, or its lack. Increased rpm during comminution produced an increased dispersion of beef or pork fat. Under the same conditions pork fat was dispersed more finely than beef fat. Dispersion of cottonseed oil produced finely dispersed particles beyond the resolution of light microscopy, as was confirmed by electron microscopy which showed a substantial number of particles to be less than 1 μ in diameter.     

矩阵乘积的行式,列式

给出了ｍ×ｍ矩阵与ｍ×ｎ矩阵的行（列）式的表达式．若Ａ＝ａ１１ａ１２…ａ１ｍａ２１ａ２２…ａ２ｍ……ａｍ１ａｍ２…ａｍｍＢ＝ｂ１１ｂ１２…ｂ１ｎｂ２１ｂ２２…ｂ２ｎ……ｂｍ１ｂｍ２…ｂｍｎ分别是ｍ×ｍ，ｍ×ｎ矩阵，则｜Ａ｜｜Ｂ｜＝｜ＡＢ｜＋∑ｉ１＜ｉ２＜…＜ｉｔｊ１＜ｊ２＜…＜ｊｔ１≤ｔ≤ｍｎ－ｔ≥ｍＮＢｉ１ｉ２…ｉｔｊ１ｊ２…ｊｔＮＡＢ１…ｍ（－１）ｓｔ＋１ｊｔ＋１…（－１）ｓｎｊｎ其中ｉ１，ｉ２，…，ｉｔ是１，２，…，ｍ中ｔ个数码；ｊ１，ｊ２，…，ｊｔ，ｊｔ＋１，…，ｊｎ是１，２，…，ｎ的一个排列；ｓｒ＝π（ｊ１，ｊ２，…，ｊｔ，ｊｒ）（ｒ＝１，２，…，ｎ）是排列ｊ１，ｊ２，…，ｊｔ，ｊｒ的反序数．     

ANALYTICAL CHARACTERIZATION OF THE PRODUCTS OF NONENZYMATIC GLYCOSYLATION OF LYSOZYME

The quantitative analysis of the reaction products of the water activity dependent nonenzymatic glycosylation of lysozyme was not straightforward. Difficulties arose in the determination of the number of bound glucose molecules because glycosylation leads to glucose mediated protein aggregation, and the likely presence of a mixture of relatively labile Schiff-base intermediates, and the more stable ketoamine products generated by Amadori rearrangement. Polyacrylamide gel electrophoresis was used to monitor protein aggregation; periodate oxidation, nuclear magnetic resonance (NMR), and oxalic acid hydrolysis combined with HPLC, emerged as the most promising methods to quantitate the degree of glycosylation. Possible interpretations are advanced to explain the apparent discrepancies in degree of glycosylation suggested by the different analytical methods evaluated.