青海省养殖三倍体虹鳟呈味核苷酸和挥发性风味物质的研究

本研究以国产虹鳟主产地-青海省龙羊峡、公伯峡和拉西瓦网箱养殖三倍体虹鳟为研究对象,采用高效液相色谱法检测分析呈味核苷酸物质,用顶空固相微萃取（headspace solid phase microextraction,HS-SPME）结合气相色谱-质谱联用（gas chromatgraph ymass spectrometry,GC-MS）分析挥发性化合物。结果显示:青海省养殖虹鳟鱼肉呈鲜味的肌苷酸含量为176~242 mg/100 g,其中,公伯峡和拉西瓦养殖虹鳟鱼肉肌苷酸含量显著高于龙羊峡产地组（P<0.05）;挥发性化合物共鉴定出69种,用气味活度值法（odor activity value,OVA）筛选出21种气味活性物质,其中壬醛、辛醛、2-壬烯醛、1-辛烯-3-醇和己醛对虹鳟鱼肉的气味贡献较大,主要呈青草味、油脂味、花香味和鱼腥味。公伯峡和拉西瓦养殖虹鳟鱼肉挥发性化合物含量整体较高。综上,青海省养殖三倍体虹鳟鱼肉呈味核苷酸含量较高,挥发性化合物种类丰富。拉西瓦和公伯峡养殖虹鳟风味相似,具有较高的肌苷酸含量和挥发性气味物质,龙羊峡养殖虹鳟新鲜度较高,鲜味及气味强度较低。研究结果可为养殖三倍体虹鳟鱼肉风味物质的分析和调控提供一定的理论依据。     

南疆舍饲湖羊不同部位肌肉品质对比分析

为了明确南疆舍饲湖羊不同部位肌肉食用特性、营养品质和风味的差异,该实验以6月龄的湖羊为研究对象,对食用品质及部分营养指标进行测定和对比分析,并采用气相色谱-质谱联用技术对湖羊不同部位肌肉中风味物质进行测定分析。在湖羊三个部位肌肉的检测中,臀肌pH值正常,嫩度为69.03 N,蒸煮损失适中,脂肪含量17.87%;背最长肌蛋白质含量最高24.99%,胆固醇含量低。利用GC-MS共检测出83种有效挥发性成分,主要包括醇类、醛类、酸类等7大类。背最长肌中醇类物质含量较高,约占40%~50%,醛类物质种类丰富;肩肌中醇类物质含量较多,挥发性风味较优;酸类物质整体差别不大。综上,臀肌中水分含量最高,嫩度更好,脂肪含量低,加工性能更好。背最长肌蛋白质含量丰富,且风味品质相对较好且膻味轻。该研究为湖羊肉的加工和销售提供一定的科学依据,为湖羊的合理开发利用提供理论指导和技术支持。     

三种不同来源的养殖青蟹肌肉感官品质比较

为了解我国渤海、东海和南海地区青蟹感官品质差异,利用感官评价、电子鼻、味觉活度值和挥发性物质分析,对3种不同来源的养殖青蟹肌肉感官品质进行了比较.结果表明,渤海和东海雄蟹肌肉的感官评分优于南海雄蟹,但南海雌蟹肌肉的感官结果优于渤海和东海雌蟹.游离氨基酸分析发现青蟹肌肉的整体滋味偏甜,甜味主要来源为精氨酸、甘氨酸和丙氨酸...     

加工前净化处理对团头鲂肌肉品质的影响

采用循环水净化装置净化处理团头鲂（Megalobrama amblycephala）,研究净化时间（0～10 d）对团头鲂肌肉品质的影响。结果表明：净化处理对团头鲂肌肉的理化成分、风味、质构及感官品质均有显著影响;随着净化时间延长,团头鲂肌肉的粗脂肪含量、总糖含量、水溶性蛋白含量、总挥发性盐基态氮（total volatile base nitrogen,TVB-N）含量、羰基值（carbonyl value,COV）和硫代巴比妥酸（thiobarbituric acid,TBA）值明显下降,游离氨基酸含量和灰分含量显著增加（P＜0.05）;质构、电子鼻及感官评价结果表明,净化处理可显著增加鱼肉的弹性、咀嚼性和甜味,降低其腥味及异味;净化处理8 d的团头鲂肌肉TVB-N含量、COV和TBA值分别比对照组（未净化处理）样品降低12.73%、20.35%和35.13%,鱼肉中的游离氨基酸含量则比对照组样品提高43.83%。综上所述,在加工前对团头鲂净化处理8 d可显著改善鱼肉的食用品质。     

不同部位驴肉风味物质差异分析

利用气相电子鼻检测分析仪等对不同部位驴肉的风味成分进行测定。共检出53种挥发性物质,以醛类为主,颈、脊、肋、腿部中醛类占比分别为76. 39%、79. 63%、82. 07%、76. 64%,具有清香和青草气味的正己醛含量最高,占醛类的56. 6%～70. 56%,气相电子鼻结果表明驴腿部与其他部位的驴肉风味存在显著差异。非挥发性成分中,呈味核苷酸以5'肌苷酸二钠(5'-IMP)为主,颈、脊、肋、腿中呈味强度值(TAV)分别为2. 86、0. 85、5. 46、6. 84。呈味氨基酸以丙氨酸(Ala)、甘氨酸(Gly)、赖氨酸(Lys)和亮氨酸(Leu)为主,且呈味基酸含量颈部脊部肋部腿部。     

不同工艺乳饼挥发性风味物质及感官品质

采用固相微萃取法,结合气相色谱-质谱联用技术,对2种不同工艺乳饼中挥发性风味成分进行检测,共检出挥发性风味化合物44种,包括脂肪酸类13种、醇类8种、酯类7种、醛类6种、酮类3种、硫类3种、烯烃苯环类4种。优化贯筋藤工艺乳饼中丁酸含量35.90 mg/100 g,低于传统酸水工艺(p<0.05),而油酸、亚油酸、α-亚麻酸、乙酸乙酯含量均高于传统酸水工艺中相应成分的含量(p<0.05)。感官品质分析结果表明,优化工艺乳饼色泽鲜亮、口感细腻、质地均匀(p<0.05),具有乳饼特有滋气味(p<0.05),较传统酸水工艺产品的感官质量得到提升。     

不同蒸煮方式青蟹肌肉感官品质分析和比较研究

为研究热水上锅蒸(热蒸)、热水下锅煮(热煮)、冷水上锅蒸(冷蒸)和冷水下锅煮(冷煮)青蟹肌肉感官品质差异,对4种烹制方式下青蟹肌肉感官品质进行分析与比较.结果表明:冷蒸雄蟹和热蒸雌蟹肌肉的感官评价较好;利用游离氨基酸的味觉活度值进行滋味分析,发现肌肉整体滋味偏甜,甜味的主要来源为甘氨酸、丙氨酸和精氨酸,且冷蒸雄蟹肌肉和...     

气相离子迁移色谱解析白砂糖和黄油对面包感官品质和风味物质的影响

以酿酒酵母菌和植物乳杆菌作为发酵剂,探讨白砂糖和黄油对面包感官品质、比容和体积、质构、挥发性风味物质的影响。结果表明：白砂糖和黄油可显著改善面包的外观、色泽、组织结构、弹性、气味和口感等;可使面包的体积提高13.80%,硬度降低35.35%,弹性降低37.91%。在挥发性风味物质主成分方面,电子鼻检测结果表明,白砂糖和黄油使面包样品形成的风味主成分区域几乎无重叠,显著改变面包样品中挥发性物质主成分,对面包中氮氧化物、硫化合物、芳香族化合物、芳烃化合物、甲烷类和乙醇等化合物的产生影响显著。在挥发性风味物质含量方面,气相离子迁移色谱检测结果表明,白砂糖和黄油显著影响面包样品挥发性风味物质的种类和含量。其中,乙酸甲酯、乙酸异戊酯、己酸乙酯、糠醛等物质的含量明显增加。这些酯类物质既是挥发性风味物质,又是发酵香气成分中的主要呈香物质。综上可知,白砂糖和黄油在改善面包的食味品质方面发挥着重要作用。     

啤酒风味的感官分析与风味优化

啤酒的风味品评是用感官分析法对啤酒的芳香及其微妙的口味差别进行鉴别的一门科学,啤酒的好与环,"味"最重要,"好喝"为根本,是理化鉴定所替代不了的。本文简单分析了淡爽风味的啤酒品评及基本风味优化措施。1基本概念感官分析是指人利用"味觉、嗅觉、听觉、触觉、视觉"五官感觉器官的功能,依据产品标准,用专业术语判断其批量合格与否。而啤酒的风味品     

特色酵子馒头的感官及风味分析

以河南商丘（SQ）、南阳（NY）、新乡（XX）3个地区的特色酵子及其发酵制作的馒头为研究对象,通过对酵子pH值与可滴定酸度、乳酸菌和酵母菌计数、感官评价、质构分析、图像分析和固相微萃取与气相色谱质谱联用法对不同地区特色酵子馒头的感官及风味物质进行定量定性分析比较。结果表明,酵子样品的pH范围是5.59~5.92;TTA范围是2.12~3.40 mL;从菌落计数上看,XX酵子中的酵母菌细胞密度最高为3.93 lg(cfu/g),SQ酵子中的乳酸菌细胞密度最高为3.39 lg(cfu/g);XX酵子馒头的质地性状、压缩张弛性和黏着性都优于其他两种酵子馒头;在图像分析中,XX酵子馒头的切片亮度、气孔对比度、气孔数量最大,壁厚、粗气孔体积、气孔直径最小,表明其内部纹理结构较好,且更被大众所喜爱;GC-MS分析可知,从XX酵子馒头中鉴定出65种挥发性风味物质,NY酵子馒头为58种,SQ酵子馒头为61种。XX酵子馒头中对风味贡献较大的是烯烃类、醇类和羧酸类,占总量的89.06%。NY酵子馒头对风味贡献较大的也是烯烃类、醇类和羧酸类,占总量的79.13%。SQ酵子馒头中对风味贡献较大的是烯烃类、醇类和酮类,占总量的66.05%。同时,这三种馒头都存在各自所特有的风味物质。结果表明:不同酵子制作馒头的感官和风味存在一定的差异,为馒头工业化生产提供理论支持。     

Comparison of Variable-Blade to Allo-Kramer Shear Method in Assessing Rainbow Trout (Oncorhynchus mykiss) Fillet Firmness

Abstract: A variable‐blade (VB) attachment was compared to the Allo‐Kramer (AK) shear attachment for texture analysis of rainbow trout fillets from 2 experiments; effects of attachment configuration, storage regimen, and cooking temperature are evaluated. In the 1st experiment, AK detected differences in force measurement, and VB showed that the perpendicular orientation yielded the highest response (P < 0.05). Fillets refrigerated (4 °C) for 0 d were firmer than fillets stored for 14 d (337.36 compared with 275.90 g/g). Raw fillets were firmer than cooked fillet (333.79 compared with 279.46 g/g). In the 2nd experiment, frozen storage at –25 °C for 30 d after refrigerated storage (R3F30 and R7F30) decreased VB shear force (P= 0.0019) and AK energy of shear (P= 0.0001) by 1.5‐ and 2‐fold compared to those evaluated after refrigerated storage for 3 and 7 d (R3 and R7), respectively. Cooking increased VB and AK texture for all storage regimens (P < 0.05). In both studies, instrumental texture did not correlate with alkaline‐insoluble hydroxyproline (P > 0.05). Shear direction affected force generated by the VB attachment, and this attachment could discriminate shear force differences due to cooking and frozen‐storage. Practical Application: Fillet texture was determined by a recently developed device and compared to texture determined by the Allo‐Kramer shear attachment; both responses were related to collagen content. The VB attachment defined fillet texture as affected by cooking and storage condition.     

Quality Assessment of Farmed Rainbow Trout (Oncorhynchus mykiss) during Chilled Storage

ABSTRACT:  The quality changes of farmed rainbow trout ( Oncorhynchus mykiss ) stored in ice for a period of up to 20 (0, 4, 8, 12, 16, and 20) d were determined by chemical (total volatile basic nitrogen [TVB-N], free fatty acid (FFA), thiobarbituric acid (TBA), peroxide value (PV), heme iron), microbiological (total viable counts, TVC), and sensory methods. The TVB-N level showed fluctuations during storage, indicating that TVB-N could not be a good indicator of rainbow trout quality. The TBA values remained low and were found to fluctuate during storage. The PV values and the release of FFA increased ( P < 0.05), while heme iron content decreased during storage. The total viable counts of rainbow trout increased ( P < 0.05) from the initial value of 4.0 log CFU/g (day 0) to 7.04 log CFU/g (day 20) over the period of storage. This study showed that sensory analysis of rainbow trout correlated well with the microbiological analysis. The results of this study according to microbiological and sensorial data indicated that the shelf life of rainbow trout stored in ice was approximately 9 to 11 d.     

Frozen Storage Quality of Rainbow Trout (Oncorhynchus mykiss) as Affected by Oxygen, Illumination, and Fillet Pigment

We investigated the influence of packaging materials with high, medium and low oxygen transmission rates (OTR) on the development of 2-thiobarbituric acid-reactive substances (TBARS) and astaxanthin retention in rainbow trout fillets. Three different levels of astaxanthin, during dark or illuminated frozen storage were studied. Samples were analyzed after 17, 29 and 36 wk frozen storage. Rancidity developed more rapidly in packages with high OTR. This effect was more pronounced in illuminated samples, also verified by sensory evaluation. Fillets with highest astaxanthin content reached maximum TBARS after 29 wk. The two less pigmented sample groups reached maximum after 17 wk frozen storage, indicating antioxidative effects of astaxanthin.     

Rapid Near Infrared Spectroscopic Method for the Detection of Spoilage in Rainbow Trout (Oncorhynchus mykiss) Fillet

The possibility of using visible and short‐wavelength near‐infrared (SW‐NIR: 600 to 1100 nm) spectroscopy to detect the onset of spoilage and to quantify microbial loads in rainbow trout (Oncorhynchus mykiss) was investigated. Spectra were acquired on the skin and flesh side of intact trout fillet portions and on minced trout muscle samples stored at 4 °C for up to 8 d or at room temperature (21 °C) for 24 h. Principal component analysis (PCA) and partial least squares (PLS) chemometric models were developed to predict the onset and degree of spoilage. PCA results showed clear segregation between the control (day 1) and the samples held 4 d or longer at 4 °C. Clear segregation was observed for samples stored 10 h or longer at 21 °C compared with the control (0 h), indicating that onset of spoilage could be detected with this method. Quantitative PLS prediction models for microbial loads were established. For trout fillets, 4 °C: R= 0.97, standard error of prediction (SEP) = 0.38 log colony‐forming units (CFU)/g (flesh side); R= 0.94, SEP = 0.53 log CFU/g (skin side); R= 0.82, SEP = 0.82 log CFU/g for minced fish held at 21 °C. These results indicate that SW‐NIR in combination with multivariate statistical methods can be used to detect and monitor the spoilage process in rainbow trout and quantify microbial loads rapidly and accurately.     

Consumer Acceptance of Brown Trout (Salmo trutta) as an Alternative Species to Rainbow Trout (Salmo gairdneri)

Rainbow trout and brown trout were prepared and distributed to consumers for comparative taste tests to determine consumer reaction to brown trout. In-home tests were standardized with paired samples of fish. Color of flesh, odor, flavor, texture and overall acceptability were recorded on a 9-point Hedonic scale. Sensory results indicated that brown trout raised in farm stock ponds were more acceptable than rainbow trout from similar environments, and rainbow trout from natural winter-kill lakes were more acceptable than brown trout from the same or similar lakes. Overall, we conclude that brown trout would be acceptable to consumers. Variations in acceptability related to water body of origin rather than to species of fish. Significant differences occurred in some characteristics but were inconsistent as to species.     

茶多酚-壳聚糖复合液对虹鳟鱼肉贮藏品质和菌群结构的影响

针对虹鳟鱼在贮藏过程中易受到微生物的污染而发生腐败变质的问题,将3 g/L茶多酚和10 g/L壳聚糖混合制成复配保鲜剂,浸泡涂膜覆盖于虹鳟鱼表面。以感官评价、挥发性盐基氮含量、菌落总数及菌群结构等为指标,研究保鲜剂对4℃贮藏虹鳟鱼肉贮藏品质变化的影响。结果表明:茶多酚和壳聚糖单独使用或复合使用均能延缓腐败的发生;复配保鲜剂能将4℃贮藏虹鳟鱼的货架期从8 d延长至13 d,效果优于单独使用;未经处理的新鲜虹鳟鱼片菌群由16个菌属组成,腐败末期则以假单胞菌属为优势菌属,而复合保鲜剂涂膜会明显抑制假单胞菌属的生长,进而减缓鱼肉品质劣变。综上,茶多酚和壳聚糖的复配保鲜剂有助于通过抑制优势腐败菌的生长延缓4℃贮藏条件下虹鳟鱼的腐败变质。     

Texture Properties of Farmed Rainbow Trout (Oncorhynchus mykiss): Effects of Diet,Muscle Fat Content and Time of Storage on Ice

Groups of rainbow trout (Oncorhynchus mykiss) fed diets with low or high fat content were stored on ice for up to 11 days in two separate experiments. After 4, 9 and 11 days storage on ice in the first experiment and after 5, 8 and 11 days in the second experiment the fish were filleted by hand and fillet gaping was evaluated. Texture properties were studied using an Instron compression test. pH was measured in all fillets. In fillets from the second experiment, also fat content and autolytic protease activity were measured. Diet affected fillet fat content and texture properties. Fish fed high fat diet exerted less resistance against compression, indicating a softer consistency. Force at yield point and slope were not significantly affected by diet. The high fat group had higher autolytic protease activity than the low fat group. The results from the Instron measurements indicated that the fish became softer and less tough during 11 days storage on ice. A slight, but statistically significant increase in pH with time was observed in both experiments. In the first experiment a reduction in gaping scores was observed during storage, as opposed to a significant increase in the second experiment. The texture parameters yield point and slope were negatively correlated to gaping in the second experiment.     

Modified Atmosphere Packaging and UV-C Radiation on Shelf Life of Rainbow Trout (Oncorhynchus Mykiss)

Effects of modified atmosphere packaging (MAP) in combination to UV-C radiation on rainbow trout fillets were examined. The samples were submitted to two treatments: (T1) aerobic package; (T2) MAP+UV-C radiation (80% CO₂/20% N_2; 106.32mJ/cm²) and were analyzed daily for microbiological (mesophilic and psychrotrophic count) and chemical (biogenic amines) parameters. MAP+UV-C radiation (T2) promoted lag phase formation and lower number of colonies in the stationary phase as well as retarded cadaverine production during storage time. MAP+UV-C radiation retard microbial growth and delay chemical changes enhancing the shelf life of rainbow trout fillets by at least twice.     

Effect of Different Cooking Methods on Minerals,Vitamins, and Nutritional Quality Indices of Rainbow Trout (Oncorhynchus mykiss)

In this study, the influence of four cooking methods (baking, boiling, microwaving, and frying) on the nutritional value of rainbow trout was determined. Proximate, fatty acid composition, vitamin, mineral contents, and nutritional quality indices of rainbow trout were investigated (i.e., before and after cooking treatments). In all samples, there was reduction of total n-3 than raw fish fillets. Considering overall nutritional quality indices, vitamin, and mineral contents; baking and boiling were the best cooking methods among other methods used in this study.     

冷熏虹鳟鱼生产工艺研究

本文主要是介绍了虹鳟鱼的加工过程中通过对加工时间的控制来观察对肉的嫩度及感观的影响。随着腌制时间的增加,产品感观评分增加,但是当腌制时间继续延长,感观评分急剧下降,一般在40～60min为益。干燥时间对鱼肉嫩度的影响比较大,随着干燥时间的延长,鱼肉中的水分大量流失,肉嫩度值增加;干燥100～140min对于产品的感观评价较好。最后确定出烘干时间对于产品的嫩度和感观评价影响最明显,腌制时间次之,确定出最佳工艺参数,即腌制50min,干燥120min,熟制90min,烟熏液浓度0.1%.