热反应鸡肉香精与水煮鸡肉挥发性风味成分的对比分析

采用SPME法萃取热反应鸡肉香精和水煮鸡肉中的挥发性风味成分,以气相色谱-质谱联用技术对挥发性风味成分进行分离鉴定,结果显示:从热反应鸡肉香精中共鉴定出49种挥发性风味成分,包括烃类9种,醛类15种,醇类6种,酮类2种,酸类3种,酯类1种,杂环化合物8种,其它化合物5种。从水煮鸡肉中共鉴定出挥发性风味成分22种,包括烃类5种,醛类6种,醇类1种,酮类2种,酯类2种,杂环化合物4种,其它化合物2种。从两者中共同鉴定出的化合物有壬醛、(E)-2-辛烯醛、苯甲醛、(E,E)-2,4-癸二烯醛、对甲氧基苯甲醛、1-辛烯-3-醇、苯乙酮、右旋萜二烯、苯乙烯、蒎烯、2-戊基呋喃、2-乙基-6-甲基吡嗪、2-乙酰基呋喃、3-呋喃甲醇、茴香脑和愈创木酚。     

河蟹酶解液Maillard反应挥发性风味成分HS-SPME-GC-MS分析

以河蟹为研究对象,对其进行酶解制备Maillard蟹肉香精,采用顶空-固相微萃取和气相色谱-质谱联用技术(HS-SPME-GC-MS)对蟹肉香精挥发性风味成分进行萃取和鉴定。结果显示:从蟹肉香精中共检测出24种挥发性香气成分,包括醇类、醛类、酚类、硫醚类、杂环类(包括吡嗪、呋喃、噻唑、噻吩、吡咯)、其他等,含量最高的分别为吡嗪类、醛类。运用OAV进行分析,得出对蟹肉香精风味有突出贡献的为二甲基三硫醚、β-紫罗兰酮、3-甲硫基丙醛、苯乙醛、2-乙基-3,5-二甲基吡嗪、5-甲基-2-噻吩甲醛等。     

花生饼粕及花生壳烘烤风味分析

采用顶空固相微萃取和气相色谱-质谱联用技术对不同花生饼粕和花生壳的烘烤风味进行分析,比较不同原料的烘烤风味强弱,并对鉴定出的挥发性风味成分进行主成分分析,明确不同原料烘烤风味的主要风味物质。结果表明:从不同花生饼粕、花生壳的烘烤风味中共鉴定出119种挥发性物质,包括醛类、酮类、烃类、吡嗪类、呋喃类、吡咯类、吡啶类、胺类和其他共9类化合物。根据不同原料烘烤风味的总峰面积进行风味强度对比,低温饼2的烘烤风味强度最高,花生壳烘烤风味强度最弱。其中,花生饼粕中的主要风味物质为吡嗪类、吡咯类、呋喃类和吡啶类等氮氧杂环化合物,而醛类和呋喃类化合物是花生壳中主要的风味物质。通过主成分分析,2,5-二甲基吡嗪、甲基吡嗪、2-乙酰基-3-甲基吡嗪、2-乙基-3-甲基吡嗪和N-甲基吡咯等化合物是烘烤花生饼粕中的主要风味物质,2-戊基呋喃、壬醛、5-甲基呋喃醛、正己醛和癸醛等化合物是烘烤花生壳中的主要风味物质。     

两种制备方式猪肉香精挥发性风味成分差异性分析

为研究微波和焙烤两种制备方式对猪肉香精挥发性风味成分的影响,采用固相微萃取法对微波和焙烤制备的猪肉香精中挥发性成分进行萃取,同时结合气相色谱-质谱联用和嗅闻技术对萃取成分进行鉴定。结果显示:微波制备的猪肉香精中共鉴定出37种挥发性成分,其种类分别为:烃类3种,醛类15种,醇类8种,酯类1种,酸类5种,杂环类3种,其它化合物2种;焙烤制备的猪肉香精中共鉴定出44种挥发性成分,包括烃类7种,醛类14种,醇类6种,酯类4种,酮类1种,酸类6种,酚类2种,杂环类2种及其它化合物2种。两种制备方式均鉴定出的共同化合物有24种,包括α-蒎烯、壬醛、反-2-辛烯醛、苯甲醛、反-2-癸烯醛、反,反-2,4-壬二烯醛、柠檬醛、芳樟醇、1-辛醇、4-甲基-5-羟乙基噻唑、草蒿脑、茴香脑等。与焙烤方式制备的猪肉香精相比,微波方式制备的猪肉香精中关键性香气物质较多,由此制备出的调味基料更接近厨房菜肴。     

GC-O与GC-MS结合分析竹荪牛肉香精中的挥发性成分

采用同时蒸馏萃取结合气相色谱-质谱联机,通过双柱定性对竹荪牛肉香精中的挥发性成分进行分析,并通过谱库检索和保留指数比对,共计从竹荪牛肉香精中鉴定出化合物169 种,其中醇类26 种、醛类21 种、酮类9 种、酸类18 种、酚类4 种、酯类4 种、醚类6 种、烃类49 种、杂环及其他类32 种,其中十六醛、丁香酚、β-倍半水芹烯、茴香脑、β-红没药烯、α-姜烯、油醇等相对含量较大;通过气相色谱-嗅觉测定法,采用芳香萃取物稀释分析法对其特征风味成分进行了分析,共鉴定出33 种特征成分,其中2-甲基-3-呋喃硫醇、α-荜橙茄烯、反-佛手甘油烯、反式石竹烯,红没药醇对牛肉香精风味贡献相对较大。     

新疆大盘鸡挥发性风味成分的GC-MS分析

为了研究新疆大盘鸡中的特征风味成分,本文采用固相微萃取(SPME)法和同时蒸馏萃取(SDE)法提取大盘鸡的挥发性风味成分,用气相色谱-质谱联用技术对挥发性风味成分进行分离鉴定。结果显示:共鉴定出85种挥发性风味成分,包括烃类23种、醛类20种、醇类15种、酮类4种、酸类3种、酯类8种、杂环及其他化合物12种。其中,醛类和杂环类化合物对大盘鸡特征香气的形成起重要作用。     

SPME-GC-MS结合GC-O分析糖醋排骨风味香精挥发性风味成分

采用固相微萃取法提取糖醋排骨风味香精中挥发性成分,并结合气相色谱-质谱联用技术和气相色谱-嗅闻技术对萃取成分进行鉴定。结果显示,糖醋排骨风味香精共鉴定出挥发性成分55种,其中烃类11种(16.45%)、醚类3种(13.41%)、醇类10种(12.38%)、其他化合物5种(12.03%)、酮类4种(5.45%)、酯类3种(3.82%)、醛类8种(3.54%)、酸类6种(3.46%)、酚类5种(1.74%)。经气相色谱-嗅闻确定糖醋排骨风味香精中的12种关键性风味成分为β-蒎烯、乙酸、糠醛、2,3,5,6-四甲基吡嗪、苯甲醛、芳樟醇、3-甲基丁酸、反-2-癸烯醛、反-2,4-癸二烯醛、4-羟基-2,5-二甲基-3(2H)呋喃酮、大茴香醛、丁香酚。     

内蒙古风干牛肉香精的调配

采用溶剂辅助风味蒸发法、固相微萃取法、同时蒸馏萃取法对内蒙古风干牛肉中挥发性风味物质进行提取,并结合气相色谱-质谱联用技术对其挥发性风味物质进行分析。结果表明:三种方法共同检测出的挥发性风味物质共有14种,包括α-蒎烯、壬醛、苯甲醛、甲基庚烯酮、芳樟醇、4-萜烯醇、糠醇、草蒿脑、茴香脑、2,5-二甲基吡嗪、2,6-二甲基吡嗪、2-乙基吡嗪、2,3-二甲基吡嗪、2,3,5-三甲基吡嗪,检出的挥发性风味物质主要包括醇类、醛类和含硫含氮及杂环化合物。在对内蒙古风干牛肉香气成分分析结果的归纳总结以及感官评价的基础上,首先调配出三个配方,然后再根据文献报道、调香经验进行配方改进实验,最终调配出香气饱满、具有风干牛肉特征香气、协调的内蒙古风干牛肉香精。     

烟草酶解液参与制备的热反应香精香气成分分析

目的研究烟草酶解液参与制备的热反应香精的香气成分。方法以甘氨酸与木糖的美拉德反应液为对照,采用固相微萃取(solid-phase micro extraction,SPME)法和同时蒸馏萃取(simultaneous distillation extraction,SDE)法提取,气相色谱-质谱联用技术对其进行分离鉴定。结果烟草酶解液参与制备的热反应香精中共鉴定出34种挥发性风味化合物,包括20种杂环类、4种酸类、3种酮类、3种醇类、2种醛类、1种酚类和1种烃类化合物。其中,杂环化合物的相对质量分数最高,且糠醛的相对质量分数最高为32.483%,含量为4.799μg/g。美拉德反应对照液中共鉴定出11种挥发性风味成分,包括7个杂环类、1个酸类、1个醛类、1个酚类和1个烃类化合物。结论与反应对照液相比,热反应烟草香精的制备过程中产生了更多的挥发性香味成分,尤其是杂环类化合物,不仅对烟草风味具有良好的修饰作用,亦为卷烟香精的重要组成成分。     

精炼过程对菜籽油风味成分的影响

采用固相微萃取技术和气相色谱质谱联用技术(SPME/GC-MS)分析菜籽油精炼过程中挥发性成分的变化情况。采用气相色谱嗅闻分析法(GC-O)中的频率检测法分析菜籽毛油中的特征风味物质并分析精炼过程中特征风味物质的变化规律。结果表明:菜籽油精炼过程中共检测到102种风味物质,包括吡嗪类4种,硫甙降解产物12种,醛类19种,醇类11种,酸类6种,酮类8种,烷烃类13种,烯类9种,杂环类10种和酯类10种;确定2,5-二甲基吡嗪、2-乙基-5-甲基-吡嗪等13种菜籽毛油中的特征风味物质;随着精炼程度的加深,吡嗪类化合物和硫甙降解产物的种类和含量显著降低,与此同时,精炼过程中产生了大量的醛类、酮类、烷烃类以及杂环类化合物,但是经过脱臭工艺之后这几类化合物的含量和种类又显著降低。     

Salmonella risk in imported fresh beef, beef preparations, and beef products

Additional guarantees (AGs) for Salmonella in imported defined animal-derived foods were agreed on for Finland when it was admitted to the European Community. The aim of this project was to evaluate the impact of these AGs on the prevalence of Salmonella in the Finnish beef supply and the adequacy of their scope. According to the quantitative Bayesian model, the efficacy of AGs was mainly dependent on the proportions of different beef categories imported and the true prevalence in the countries of origin. According to the model, AGs were able to reach their target in the referred year 1999 and kept the true Salmonella prevalence of beef imports below 1% with quantified uncertainty. The extension of AGs to all imported fresh beef would have reduced the Salmonella prevalence of beef imports from three- to fourfold, whereas expanding the implementation of AGs to all imports of fresh beef, beef preparations, and beef products would have resulted in a sixfold decrease. If current AGs targeting fresh beef intended to be sold as fresh or to be processed by the Finnish industry with processes not achieving 70 degrees C were not implemented, the 95% credible interval of Salmonella prevalence in the Finnish beef supply would be 0.2 to 1.3% (mean, 0.6%) instead of 0.1 to 1.2% (mean, 0.5%). However, if the prevalence in the exporting countries were to rise or the main import countries and/or magnitudes were to change, AGs would be of greater importance.     

Microbiological contamination of raw beef trimmings and ground beef

To survey the microbiological quality of beef trimmings and final-ground beef, samples were collected from eight commercial grinding facilities, including trimmings from fed-cattle, culled-beef cows, culled-dairy cows, imported-beef trimmings and finished-ground products. Trim samples (core and purge) and ground product samples (n=586) were evaluated for aerobic plate (APC), total coliform (TCC), Escherichia coli (ECC) and Staphylococcus aureus counts and the presence of Salmonella spp. and Listeria monocytogenes. As fat content in the trimmings increased, APC also increased. Trimmings from fed-cattle had higher (P<0.05) APC and TCC than trimmings from culled-beef cows, culled-dairy cows and imported trimmings. Purge samples produced higher (P<0.05) APC, TCC and ECC than core samples, but there were no difference (P>0.05) across fat percentages in APC, TCC, ECC or S. aureus counts. Final-ground beef samples had a 13.6 and 1.5 % incidence of L. monocytogenes and Salmonella spp., respectively. The results of this study indicate specific areas of potential that ground beef processors could capitalize upon to further improve the microbiological quality of their finished product. Ground beef processors should focus their efforts on reducing the microbial counts on incoming raw materials, especially those containing large proportions of subcutaneous fat, and processors should no longer incorporate the purge component of raw materials into ground beef. From this study, it is also apparent that ground beef processors should implement sanitation and manufacturing procedures that address L. monocytogenes contamination.     

卤牛肉与牛肉高汤联合生产技术

主要阐述卤牛肉与牛肉高汤联合生产工艺,分析了产生的经济效益。     

Consumer attitudes towards beef and acceptability of enhanced beef

The objective of this study was to evaluate consumer quality characteristics of enhanced steaks and roasts derived from cattle supplemented with vitamin E during finishing, and to assess the attitudes of these consumers towards beef. Twelve steers were fed either a control (E-) diet or a diet supplemented with dl-alpha tocopheryl acetate (E+). Paired strip loins and rounds were either used as controls (C) or were pumped (P) to 110% of raw weight to contain 0.4% sodium chloride and 0.4% sodium tripolyphosphate in the final product. Consumers (n=103) evaluated roasts and steaks for juiciness, tenderness, saltiness, and overall acceptability on a 9-point hedonic scale. Enhanced steaks and roasts were more acceptable than non-enhanced controls; E+ steaks were less acceptable than E- steaks. A beef quality questionnaire revealed that color, price, visible fat and cut were the most important factors underlying beef steak purchase, while tenderness, flavor and juiciness were weighted most heavily with regard to eating satisfaction.     

Differentiation between fresh beef and thawed frozen beef

In order to prevent meat retailers offering thawed, imported frozen beef as fresh domestic beef, the method of Gottesmann and Hamm for differentiating between fresh and frozen/thawed meat is recommended. The principle of this method is based on the fact that freezing and thawing of meat results in a release of the enzyme β-hydroxyacyl CoA-dehydrogenase (HADH) from the mitochondrion into the sarcoplasm; an elevated HADH activity in the muscle press-juice indicates freezing and thawing of tissue. The HADH colour test of Gottesmann and Hamm was modified by replacing the electron-transmitter meldolablue by resazurin which results in a much higher colour stability after reaction with fresh meat extracts.     

Freeze-drying of beef. I. Theoretical freeze-drying rates of beef

Summary. A theoretical model of freeze-drying is developed from which the dependence of drying rate and ice temperature on processing conditions can be calculated. The theory is based on the measured permeability and thermal conductivity of the completely dry material. When applied to beef steaks, the theory predicts that, at acceptable surface temperatures, the system is heat transfer limited and that the fastest sublimation rates should be obtained at high product surface temperatures combined with high cabinet pressures; if however the surface temperature is low (less than 20°C) the cabinet pressure should also be kept low. The probable effects of pre-drying treatments such as slow freezing and cooking are also discussed.     

牛肉香气成分的分析及其香精的开发

本文介绍了牛肉挥发性成分的提取方法、牛肉香气成分组成以及牛肉香精的开发.常用的分析方法有气相色谱-质谱联用技术(GC-MS)和气相色谱-嗅觉检测技术(GC-O).采用甲硫醇、呋喃硫醇、吡嗪、反-2,4-壬二烯醛和呋喃酮等主要的牛肉香气成分香原料,可以调配出香气逼真的炖牛肉香精.     

Moisture sorption isotherm of fresh lean beef and external beef fat

The moisture sorption isotherm (MSI) of lean beef and fat beef was experimentally determined. The experimental procedure used was that of the COST 90 project with some modifications to accelerate equilibration. The procedure was validated with the standard reference material microcrystalline cellulose. The MSI of the beef at the highest humidity range was obtained by accelerating equilibration with changes of salts, using a low water activity salt for some time. This procedure was reliable for beef samples but not for the fat samples. No significant changes were found for lean beef in the temperature range 5–40 °C. Three models, GAB, Peleg and Lewicki, were used to fit the experimental data. The best fit was obtained with the GAB equation. The fat MSI was determined at 5, 15 and 25 °C and it was best fitted with the Lewicki model.     

牛肉大理石纹形态、分布状态与牛肉质量的研究

牛肉大理石纹是优质牛肉的主要技术指标.对牛肉大理石纹的形状、分布状态与牛肉质量的关系进行了研究.结果表明:牛肉大理石纹的适量形成、脂肪沉积形状小条近似粒状的均匀分布与牛肉的嫩度、多汁性和适口性有正相关性.