苹果汁鉴伪技术研究进展

果汁掺假现象已成为影响果汁行业又好又快健康发展的制约因素之一.概述苹果汁中的不同掺假现象和掺假手段,并综述国内外苹果汁鉴伪技术及其研究进展.     

δD,δ~(18)O和δ~(13)C同位素比率质谱法在鲜榨苹果汁鉴伪中的应用

为识别苹果汁中糖和水的掺假,采用同位素比率质谱法(isotope ratio mass spectrometry,IRMS)对不同品种的鲜榨苹果汁和掺假果汁的δD,δ~(18)O和δ~(13)C值进行分析确定。结果表明,鲜榨苹果汁水的δD,δ~(18)O值均显著高于外源水掺假的果汁,且掺假果汁水的δD与δ~(18)O值呈线性关系,同时δD、δ~(18)O值随掺水量增加而降低;δ~(13)C值显示鲜榨苹果汁中糖组分含量分别为:果糖-25.64‰～-26.83‰,葡萄糖-25.01‰～-26.36‰,二糖-22.41‰～-23.24‰;果糖、葡萄糖、二糖占总糖的百分比范围分别48.84%～52.39%,14.34%～28.85%,10.47%～18.78%,未检出寡糖,掺假果汁二糖的δ~(13)C值不在上述范围。说明鲜榨果汁与掺假果汁的碳氢氧稳定同位素比率存在着差异,可进一步探索建立数据库以用于市售鲜榨苹果汁掺假的判别,为IRMS在果汁鉴伪中的应用提供试验依据。     

苹果汁的掺假鉴定

从糖、有机酸、氨基酸、稳定性同位素、类黄酮、阳离子及光谱学等方面全面探讨了真假苹果汁的鉴定方法，为苹果汁加工业提出了一系列行之有效的鉴定掺假方法。     

苹果汁中果汁含量测定方法研究

原果汁含量是苹果汁及其饮料的主要质量指标,也是判定苹果汁是否掺假的重要依据。通过对6个产地5个品种自制苹果汁的部分组分进行研究,找出与苹果汁含量有良好定量关系的特征性组分——钾、总磷和氨基酸态氮,以它们作为苹果汁含量测定参数,并且确定了各组分的标准值、权值分配方案及异常数据修正原则。据此,推导出苹果汁含量计算公式;同时按此法对自制的苹果汁和市售的6个品牌的苹果汁进行了果汁含量测定,进一步验证了此方法的可行性。此方法可用于苹果汁果汁含量测定或用于鉴别苹果汁的真伪。     

元素分析/液相色谱-碳同位素比值质谱法在纯正 苹果汁掺假鉴别中的应用

目的建立一种鉴别检测苹果汁掺假情况的元素分析/液相色谱-同位素比值质谱法(elemental analysis/liquid chromatography-isotope ratio mass spectrometry,EA/LC-IRMS)。方法通过对不同产区不同种类118个纯正苹果汁的糖、有机酸、果糖、葡萄糖、二糖、寡糖碳同位素比值(δ~(13)C值)的测定,建立纯正苹果汁同位素数据库进而提出纯正苹果汁应满足的δ~(13)C值要求。结果有机酸和糖差值Δδ~(13)CO-S在-1.38‰至1.09‰范围内,果糖和葡萄糖差值Δδ~(13)CF-G在-0.70‰至0.57‰范围内,而各组分最大差值Δδ~(13)Cmax4.36‰。对市售105个苹果汁进行检测,采用本方法检出32个阳性样品,而采用本实验室的糖浆标志物法仅检出12个阳性样品。结论本方法大大提高了苹果汁的掺假鉴别,有很大的实际应用潜力。     

基于有机酸HPLC指纹图谱的甜樱桃果汁掺假鉴定

根据甜樱桃果汁中有机酸的高效液相色谱（high performance liquid chromatography,HPLC）分析方法,利用“中药色谱指纹图谱相似度评价系统（V2.0）”软件建立甜樱桃果汁的有机酸HPLC指纹图谱,并通过相似度评价、主成分分析和聚类分析,对模拟在甜樱桃果汁中添加低价果汁（梨汁、苹果汁、杏汁和桃汁）和外源柠檬酸等掺假方式进行鉴别。结果表明：42 个甜樱桃果汁的有机酸指纹图谱与对照指纹图谱的相似度均在0.948以上,不同品种、不同采收时间的甜樱桃果汁的指纹图谱具有很好的一致性,甜樱桃果汁中添加其他果汁或柠檬酸可导致相似度降低;结合主成分分析和聚类分析等模式识别方法,可以实现对甜樱桃果汁与掺假低价果汁（梨汁、苹果汁、杏汁和桃汁）及外源柠檬酸样品的区分,而且掺假量越大,识别效果越好,而相似度评价仅能识别掺假量较高的样品。甜樱桃果汁有机酸HPLC指纹图谱结合化学计量学分析,对于掺假甜樱桃果汁具有较好的区分效果,可用于甜樱桃果汁掺假鉴定和质量控制。     

草莓汁中糖酸组成分析及其在掺假鉴别中的应用

为了解草莓汁的糖酸组成特点并探索其在掺假鉴别中的应用,采用高效液相色谱法对10个品种草莓果汁中可溶性糖、有机酸组成与含量进行分析,结合化学计量学方法探索其在草莓汁掺假鉴别中的应用。结果表明,草莓汁中可溶性糖主要由蔗糖、葡萄糖和果糖组成,有机酸主要是柠檬酸和苹果酸。不同品种草莓果汁中各种可溶性糖和有机酸的含量存在较大差异,但葡萄糖与果糖的比值受品种影响较小,柠檬酸占检测到总有机酸含量的62.39%~82.73%。通过分析草莓原汁及其掺假样品中可溶性糖和有机酸组成,结合主成分分析和线性辨别分析等模式识别方法,可以实现对草莓果汁与掺加梨汁、苹果汁、杏汁和桃汁等掺假样品的区分,而且掺假量越大,区分效果越好。草莓果汁可溶性糖和有机酸组成特征结合化学计量学分析能够对掺假草莓果汁进行较好地区分,可用于草莓果汁掺假鉴定和质量控制。     

蓝莓汁有机酸高效液相色谱指纹图谱构建及其在掺假鉴定中的应用

根据蓝莓汁中有机酸的高效液相色谱(high performance liquid chromatography,HPLC)分析方法,利用"中药色谱指纹图谱相似度评价系统(V2.0)"建立蓝莓汁的有机酸HPLC指纹图谱,并通过相似度评价、主成分分析和聚类分析,对模拟掺假低价果汁(梨汁、苹果汁、杏汁和桃汁)和外源柠檬酸的蓝莓汁进行鉴别。结果表明:10个蓝莓汁样品的有机酸HPLC指纹图谱之间相似度均在0.950以上,与对照指纹图谱的相似度均在0.978以上,不同品种、不同产地的蓝莓果汁的指纹图谱具有很好的一致性,蓝莓果汁中添加其他果汁或柠檬酸可导致相似度降低;结合主成分分析和聚类分析等模式识别方法,可以实现对蓝莓汁与掺假低价果汁(梨汁、苹果汁、杏汁和桃汁)及外源柠檬酸样品的区分,而且掺假量越大,识别效果越好,而相似度评价仅能识别掺加量较高的样品。有机酸HPLC指纹图谱结合化学计量学分析,对于掺假蓝莓果汁具有较好的区分效果,可用于蓝莓汁掺假鉴定和质量控制。     

模糊数学评判苹果汁豆奶饮料的生产配方

以大豆、苹果汁为主要原料,添加适量的甜味剂、酸度调节剂、乳化稳定剂,配制出营养丰富,风味良好的苹果汁豆奶饮料;探讨了苹果汁豆奶饮料的生产工艺流程和操作要点;通过正交实验和模糊数学评判得到该饮料的最佳配方.结果表明,苹果汁豆奶饮料的最佳配方为:豆奶40%,苹果汁10%,蔗糖10%,柠檬酸0.1%.所得产品色泽均匀,香味协调,组织细腻,酸甜可口.     

开菲尔菌种发酵苹果汁的应用

开菲尔粒由乳酸细菌和酵母菌组成,经开菲尔粒发酵产生的食品舍有多种对人体有益的成分及醇香物质.为了提高苹果汁的生理功效、改善苹果汁的口感、增加苹果汁的货架期,使用开菲尔粒对苹果汁(糖度为为15、20、25 °Bx)进行发酵,开发了低醇度发酵苹果汁.其最佳工艺为30℃下接种培养72 h(接种量3%),此工艺下苹果汁的含糖量减少1%,pH值变化不大,乙醇含量达到0.5%,产生了足量的CO2气体,从而获得口感丰富良好的发酵苹果汁.     

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.     

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。     

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.     

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.     

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。     

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.     

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.     

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．