同位素内标法测定欧李果汁游离氨基酸及成分分析

采用高效液相色谱-质谱联用(LC-MS/MS)同位素内标法,测定了欧李果原汁中游离氨基酸。结果表明,欧李果原汁中共检测出28种游离氨基酸,总含量为1640.1mg/L;人体必需8种氨基酸含量为86.8mg/L,婴幼儿必须氨基酸含量为16.2mg/L;支链氨基酸含量为34.6mg/L;脯氨酸含量为832.1mg/L;天门冬酰胺含量为300.5mg/L;γ-氨基丁酸含量为169.7mg/L。总结了脯氨酸、天门冬酰胺、γ-氨基丁酸营养价值,分析了其积累的原因。     

Influence of ultra-high pressure homogenisation on physicochemical and sensorial properties of orange juice in comparison with conventional thermal processing

The effect of different ultra-high pressure homogenisation (UHPH) treatments on physicochemical and sensorial properties of orange juice was studied in comparison with thermal pasteurisation (90 °C, 1 min). UHPH treatments consisted on combinations of two inlet temperatures (10 or 20 °C) and three pressures (100, 200 and 300 MPa). Effect of treatments was assessed on general quality parameters (colour, pH, °Brix, titratable acidity, reducing sugars and non-enzymatic browning index), particle size distribution and cloud stability. None of the UHPH treatments caused significant differences in the °Brix, reducing sugars, pH and non-enzymatic browning index with respect of fresh or pasteurised juice. Only titratable acidity was significantly lower when inlet temperature of UHPH treatments was 20 °C. UHPH treatments significantly reduced the particle size and in consequence the cloudiness and the total colour value (∆E*) increased. The overall consumer acceptability of UHPH and pasteurised juices was similar.     

现代分离技术与装备在橙汁加工中的应用

现代科技的发展以及人类社会对食品安全、营养与健康要求的提升,推动了果蔬汁加工技术由传统型向现代产业型转变的进程。现代的果蔬汁加工除应用流体与流体输送、热力学（传导与热交换）、生物学（酶制剂）、制冷技术等工程原理之外,已经扩展到高效榨汁、固液分离、蒸发浓缩、蒸馏与精馏、萃取、吸附与离子交换、膜分离等物理分离技术与装备的应用方面。在橙汁加工中,不仅要求去除对橙汁风味、品质构成不利影响的橙皮精油、橙皮苷物质,同时还要求最大限度减少热敏物质及维生素C等成分的损失。讨论了采用物理分离技术与装备同其他作业单元的完美组合,限制对橙汁品质构成不利影响物质的引入,降低营养成分的损失,使得橙汁获得色、香、味俱佳品质的方法;并对备受关注的橙汁加工副产品橙皮渣废弃物转化为新资源进行综合利用,提升新的经济增长点提出了建议。     

Choice probability for apple juice based on novel processing techniques: Investigating the choice relevance of mean-end-chains

The main aim of this study is to investigate an old challenge for means-end chain (MEC) theory; the lack of demonstration for means-end chains choice relevance. Even though MEC has become a commonly used tool in commercial market research and has been widely used in applied consumer research, within the core of academic consumer research, MEC has been almost ignored. One plausible explanation for this lack of interest may be that studies linking MEC data to choice have been few. In this study, we are to investigate how values and consequences generated from a previous MEC study structure can be linked to likelihood of choice.Hypotheses about European consumers’ likelihood of choice for novel processed juice are stated and tested in a rating based conjoint study in Norway, Denmark, Hungary and Slovakia. In the study, consumers probability of choice for high pressure processed (HPP) juice and pulsed electric field (PEF) juice are compared with their probability of choice for pasteurized juice and freshly produced apple juice, and consumer choices are tried explained by values and consequences generated from a MEC study. The study support, at least partly, that means-end chain structures’ have choice relevance.     

Concentration of Umami Compounds in Pork Meat and Cooking Juice with Different Cooking Times and Temperatures

This study examined the concentrations of umami compounds in pork loins cooked at 3 different temperatures and 3 different lengths of cooking times. The pork loins were cooked with the sous vide technique. The free amino acids (FAAs), glutamic acid and aspartic acid; the 5′‐nucleotides, inosine‐5′‐monophosphate (IMP) and adenosine‐5′‐monophosphate (AMP); and corresponding nucleoside inosine of the cooked meat and its released juice were determined by high‐performance liquid chromatography. Under the experimental conditions used, the cooking temperature played a more important role than the cooking time in the concentration of the analyzed compounds. The amino acid concentrations in the meat did not remain constant under these experimental conditions. The most notable effect observed was that of the cooking temperature and the higher amino acid concentrations in the released juice of meat cooked at 80 °C compared with 60 and 70 °C. This is most likely due to the heat induced hydrolysis of proteins and peptides releasing water soluble FAAs from the meat into the cooking juice. In this experiment, the cooking time and temperature had no influence on the IMP concentrations observed. However, the AMP concentrations increased with the increasing temperature and time. This suggests that the choice of time and temperature in sous vide cooking affects the nucleotide concentration of pork meat. The Sous vide technique proved to be a good technique to preserve the cooking juice and the results presented here show that cooking juice is rich in umami compounds, which can be used to provide a savory or brothy taste.     

马铃薯淀粉废水中蛋白质和游离氨基酸的回收研究

利用天然聚电解质复合法回收马铃薯淀粉废水(PFJ)中蛋白质,并用离子交换色谱法分离纯化游离氨基酸。选用阴离子多糖卡拉胶(CG),研究了复凝聚过程中的相行为和不同p H、蛋白/卡拉胶比例对蛋白质回收效果的影响,并选用001×8型苯乙烯强阳离子交换树脂回收游离氨基酸。确定了最佳蛋白质回收条件,在p H3.5,蛋白/卡拉胶=2.5∶1(w/w)下,蛋白质回收率达到100%。游离氨基酸回收率达88.4%,氨基酸干基含量达89.5%。本研究得到的实验条件使得马铃薯淀粉废水中含氮物质得到充分回收,为其处理提供一定的指导作用。      

Effect of processing and cooking on the content of minerals and protein in pasta containing buckwheat bran flour

Research was conducted to determine the effect of processing and cooking on the ash content and mineral composition and on protein content and amino acid composition of spaghetti that was fortified with 250 g kg^?1 buckwheat bran flour (BBF). Extrusion and drying temperature had little or no effect on ash and mineral content of spaghetti containing BBF. Drying temperature did not affect protein content; however, a 31% reduction in lysine content was observed in spaghetti containing BBF dried at 90 °C. Cooking spaghetti fortified with BBF reduced ash content by 28%. Reduction in ash content was reflected by an average decrease in potassium of 62%, in copper of 45%, and in zinc of 11%. Cooking had little or no effect on content of calcium, iron, magnesium, or manganese. As a result of material leaching from spaghetti during cooking, the protein content and content of each amino acid (db) were greater in cooked than uncooked spaghetti. Copyright © 2007 Society of Chemical Industry     

甘蔗混合汁粒径分布及陶瓷微滤膜过滤阻力研究

建立了甘蔗混合汁中颗粒粒径分布测定和分析方法;研究了0．1μm、0．2μm和0．45μm陶瓷微滤膜分析甘蔗混合汁时的阻力分布,探讨了不同膜元件主要阻力形式,确定了阻力分析方法。结果表明：致密性膜的制造精度越高,过滤料液时总阻力相对较小,孔隙率高的膜元件堵塞阻力随膜孔径减小而降低,利于膜通量的恢复和延长使用时间。     

Mung Bean: Technological and Nutritional Potential

Mung bean (Vigna radiata (L.) R. Wilczek) has been intensively researched; scattered data are available on various properties. Data on physical, chemical, food processing, and nutritional properties were collected for whole mung bean grains and reviewed to assess the crop's potential as food and to set research priorities. Results show that mung bean is a rich source of protein (14.6–33.0 g/100 g) and iron (5.9–7.6 mg/100 g). Grain color is correlated with compounds like polyphenols and carotenoids, while grain hardness is associated with fiber content. Physical properties like grain dimensions, sphericity, porosity, bulk, and true density are related to moisture content. Anti-nutrients are phytic acid, tannins, hemagglutinins, and polyphenols. Reported nutrient contents vary greatly, the causes of which are not well understood. Grain size and color have been associated with different regions and were used by plant breeders for selection purposes. Analytical methods require more accuracy and precision to distinguish biological variation from analytical variation. Research on nutrient digestibility, food processing properties, and bioavailability is needed. Furthermore, the effects of storage and processing on nutrients and food processing properties are required to enable optimization of processing steps, for better mung bean food quality and process efficiency.     

反复卤煮对老汤品质的影响研究

传统酱卤肉制品因老汤的使用而深受消费者喜爱,卤汤在连续的使用过程中不断积累较多的可溶性滋味物质,使其本身具有鲜醇浓厚独特的美味,进而赋予卤煮制品特有的滋味。本研究以白羽肉鸡鸡腿为原料,对传统卤煮工艺不同卤制次数卤汤中的营养物质如蛋白质、游离氨基酸、呈味核苷酸、味精当量等和有害物质中的杂环胺的变化进行研究。结果表明:与对照组第0锅卤汤相比,当卤制次数达到第9锅时,卤汤中蛋白质含量由0.09%增加至3.86%,总游离氨基酸含量由68.57 mg/100g上升至601.92 mg/100 g,呈味核苷酸含量由0.78 mg/100 g达到了22.97 mg/100 g,味精当量(EUC)值由0.0068 g MSG/100 g升高至1.32 g MSG/100 g,但有害物质中杂环胺含量由12.29 ng/g上升至28.64 ng/g。因此,传统卤煮工艺中随着卤制次数的增加,卤汤中营养物质的含量呈不断上升的趋势,同时有害物质中杂环胺的含量也不断富集。     

Effect of Novel Starter Culture on Reduction of Biogenic Amines,Quality Improvement,and Sensory Properties of Doenjang,a Traditional Korean Soybean Fermented Sauce Variety

To select appropriate microorganisms as starter cultures for the reliable and reproducible fermentation of soybean fermented products of Korean Doenjang, various ratios of fungi (Aspergillus oryzae J, Mucor racemosus 15, M. racemosus 42) combined with Bacillus subtilis TKSP 24 were selected as either single, double, or multiple Meju strains for commercial mass production of Doenjang, followed by analysis of sensory characteristics. In the sensory evaluation, Doenjang BAM15‐1 and BAM42‐1, which were fermented with multiple strains (1:1:1), showed the highest sensory scores as compared to control. Based on sensory characteristics, 6 Doenjang samples were subjected to quantitative determination of amino acids, free sugars, and organic acids (volatile and nonvolatile) contents, followed by determination of biogenic amines. Total sweet taste amino acid contents were highest in BAM15‐1 and BAM42‐1 samples (333.7 and 295.8 mg/100 g, respectively) and similar that of control (391.1 mg/100 g). Samples BAM15‐1 and BAM42‐1 showed the relatively high volatile and nonvolatile organic acid contents (154.24, 192.26, and 71.31, 82.42 mg/100 g, respectively). In addition, BAM15‐1 and BAM42‐1 showed negligible biogenic amine formation, ranging from 0.00 to 1.02 and 0.00 to 3.92 mg/100 g, respectively. These findings indicate that determination of food components along with sensory and quality attributes using multiple microbial Meju strains as a starter culture may provide substantial results on improved quality fermented Doenjang products.     

烤烟游离氨基酸与感官质量的相关性研究

对昆明地区红大C3F烟叶中游离氨基酸与感官评吸指标之间的关系进行了主成分分析、偏相关分析及典型相关分析。偏相关分析结果表明,游离氨基酸组分与感官评吸大部分指标之间存在显著相关关系,其中精氨酸、蛋氨酸、酪氨酸对感官质量的贡献较大,缬氨酸对评吸的负面影响较大。典型相关分析也表明,游离氨基酸与烟叶感官质量有显著相关性,且主要是由酪氨酸、精氨酸、蛋氨酸、甘氨酸、浓度、香气量、劲头、丰富性、甜度、杂气和刺激的相关显著引起的。典型相关与偏相关分析结果均表明,在一定范围内提高蛋氨酸、精氨酸、酪氨酸、甘氨酸、异亮氨酸含量,有利于改善烟草的抽吸品质,而这5种游离氨基酸在烟叶中的含量都较低,说明游离氨基酸含量超出一定浓度范围,反而会降低烟叶的抽吸品质。     

Human Milk Banking: Influence of Different Pasteurization Temperatures on Levels of Protein Sulfur Amino Acids and Some Free Amino Acids

Human milk is frequently heat‐treated in hospitals, particularly milk that is banked, to destroy contaminating bacteria and viruses, but this treatment simultaneously reduces the content of some vitamins, enzymes, and immunological and nutritional factors. This study was performed to find the optimal conditions for heat treatment. The effects of 2 pasteurization temperatures on levels of protein sulfur amino acids (methionine, cystine) and some free amino acids (taurine, glutamine, glutamic acid) in light of the oxidative instability that occurs especially during thermal treatment were examined. These substances in raw human milk and in milk treated at 56.5 °C and 62.5 °C for 30 min were compared. Samples of mature human milk from all feeds over 24 h were obtained from 13 healthy well‐nourished mothers of term infants. Each sample was divided into 3 parts: raw, treated at 56.5 °C for 30 min, treated at 62.5 °C for 30 min. The results showed that the availability of sulfur amino acids and free taurine is the same after heat treatment, whereas milk processing increased positively the levels of free glutamic acid and glutamine, but there is significance only for glutamine. The mean quantities of considered amino acids were similar in milk treated at the recommended pasteurization temperature (30 min at 62.5 °C) and at 56.5 ° for 30 min.     

基于营养与智能感官综合比较不同烹饪方式下芫根的品质差异

为筛选出芫根的适宜烹饪方式,本研究利用氨基酸自动分析仪、电子舌和食品热量检测仪（Calory Answer）比较了5种烹饪方式（水煮、气蒸、微波、高压和油炒）下芫根游离氨基酸、整体滋味和营养成分的差异,同时对芫根的抗氧化活性进行了分析。结果表明：新鲜芫根中总游离氨基酸含量为261.06 mg/100 g,以甜味氨基酸为主,气蒸、微波和油炒后芫根中总游离氨基酸的含量分别提高90.50%、59.74%和83.92%,其中苦味氨基酸比例增加;水煮能够增加酸味和鲜味氨基酸的比例,减少苦味氨基酸比例。油炒、微波和高压能显著提高芫根的能量和碳水化合物含量,气蒸和油炒能显著提高其多酚含量和抗氧化活性（P<0.05）。电子舌能有效区分不同方式烹饪的芫根,水煮和气蒸的芫根滋味较为接近,微波和高压的相似,油炒的较其他相比滋味差异较大。主成分综合评价分析表明：芫根最适宜的烹饪方式是气蒸,其次是油炒。     

鲈鱼风干成熟工艺及对蛋白质水解和感官品质影响

以鲈鱼(Japanese Sea Bass)为原料进行风干成熟工艺正交试验,研究风干成熟温湿度、时间、用盐量工艺因素对产品品质及蛋白质水解规律的影响。结果表明：蛋白质水解指数(PI)随着温度提高持续增加,而游离氨基酸总量(ΣFAA)表现出先升后降的趋势;风干成熟温度对PI 和ΣFAA 有极显著影响(P ＜ 0.01);以ΣFAA 为响应的回归优化结果为：风干成熟温度15～29℃、相对湿度70%～82%,工艺时间72h,加盐量4.5%,风干成熟产品的盐分含量为2.84%、水分含量为64.33%,与感官品质评定结果有良好的一致性。     

Effect of processing methods on spinach: Proximate composition in fatty acids and soluble protein

The proximate composition and fatty acid content of spinach were determined in two processing stages. Crude protein and ash content were 2.89% and 1.96%, respectively. The total lipid content was 0-61%. The predominant fatty acids were palmitic (16:0), hexadecadienoic (16:2), hexadecenoic (16:1), stearic and hexadecatrienoic (18:0 and 16:3), oleic (18:1), linoleic (18:2) and linolenic (18:3). Little loss was observed as a result of processing. Soluble protein content showed losses of up to 87% during processing.     

热处理方式对鲈鱼游离氨基酸及品质影响

海鲈鱼因其味道鲜美、肉质细嫩深受消费青睐.不同的热处理方式对于鱼肉的品质影响较大.通过结合烹饪损失、感官评定、色泽、质构和游离氨基酸含量等多项指标,评估传统沸煮和低温真空烹饪对鲈鱼品质的影响,结果表明低温真空烹饪的鲈鱼无论是在烹饪损失、质构,还是在游离氨基酸含量方面均具有较好的优势,在感官评定上可接受度较高.该研究结果...