Quality changes during storage of cooked and sliced meat products measured with PTR-MS and HS-GC–MS

The changes in the VOC composition of industrially produced saveloy were measured with Proton-Transfer-Reaction Mass-Spectrometry (PTR-MS) and HeadSpace Gas chromatography–mass spectrometry (HS-GC–MS) during a six weeks storage period. A decrease in the volatile organic compounds contributing to the fresh aroma of saveloy was the main change observed with both PTR-MS and HS-GC–MS. Samples of four other types of cooked and sliced meat product were measured with PTR-MS in the middle and at the end of the four week shelf-life period. These measurements showed an increase in m/z 69, 71, 87 and 89 for the pork loin and in m/z 61 for the herbal saveloy samples. These ions were assigned to the microbial spoilage markers: acetic acid, 2- and 3-methylbutanol, 2- and 3-methylbutanal, diacetyl and acetoin. Overall, this study shows that PTR-MS has potential for quality control of cooked and sliced meat products.     

电子鼻、电子舌分析和感官评价在鱼糜种类区分中的应用

以五种鱼糜(淡水鱼糜:草鱼糜、鲢鱼糜和鳙鱼糜;海水鱼糜:带鱼糜和鳕鱼糜)为研究对象,利用电子鼻和电子舌对其挥发性成分和水溶性成分进行检测,所得数据以主成分分析法和聚类分析法进行分析,同时三种淡水鱼糜采用五点强度法和三点检验法进行感官评价。结果表明,电子鼻、电子舌及感官评价均能有效区分淡水鱼糜和海水鱼糜,且对两种海水鱼糜区分效果较好,但未能将三种淡水鱼糜区分开;三种淡水鱼糜感官评价结果显示,三者土腥味突出、肉香味强,而油脂味略有差异。      

Sensory and chemical analysis of cooked porcine meat patties in relation to warmed-over flavour and pre-slaughter stress

Two independent sensory profiles were carried out to evaluate warmed-over flavour (WOF) development in cooked, chill-stored and reheated pork patties. The patties were derived from the Musculus semimembranosus of animals subjected to different pre-slaughter stress treatments. All patties were stored in oxygen permeable bags at 4°C for 0, 1, 2, 3 and 5 days to facilitate WOF development. In addition, thiobarbituric acid reactive substances (TBARS), conjugated dienes, pH, water content, total lipids and the fatty acid compositions of phosphatidyl choline (PC), phosphatidyl ethanolamine (PE) and total lipids, were measured in the cooked meat patties. A data analytical strategy involving Analysis of Variance-Partial Least Squares Regression (ANOVA-PLSR), to determine relationships between the design variables (WOF and pre-slaughter stress) and the sensory-chemical data, and PLSR to elucidate predictive links between the sensory and chemical data was utilised. WOF was found to involve the development of lipid oxidation derived nuance off-flavour and odour notes, e.g. rancid-like flavour and linseed oil-like odour, in association with a concurrent decrease in cooked pork meat-like flavour. The reduction in "meatiness", over the initial days, 0-2 of WOF development was attributed to the degradation of both, unstable sulfur-containing amino acids in meat proteins and sulfur-containing "meaty" aroma compounds. Whereas, at the later days, 3-5 of WOF development the "meaty" loss was ascribed to perceptual masking by lipid oxidation products. TBARS and conjugated dienes were found to be significant (P<0.05) predictors of the sensory terms related to the lipid oxidation aspect of WOF. Whilst the polyunsaturated fatty acid (PUFAs) contents of PE, PC and the total lipids were found to decrease with WOF development, reflecting their loss in lipid oxidation reactions. The sensory variation related to pre-slaughter stress appeared to be distinct from WOF variation and was described by a sour to sweet taste continuum. However, interactions were noted that indicated increasing pre-slaughter stress resulted in a decreased sensory perception of WOF. Moreover, pH and water content were found to significantly (P<0.05) predict the sensory effects resulting from pre-slaughter stress.     

Warmed-over flavour analysis in low temperature-long time processed meat by an "electronic nose"

The ability of an electronic nose, comprising 32 conducting polymer sensors, to identify and classify warmed-over flavour (WOF) aroma in bovine semitendinosus muscle, processed by vacuum cook-in-bag/tray technology (VCT) and storage under refrigerated conditions, was evaluated. The VCT process employed low temperature-long time (50°C-390 min) thermal treatments. Multivariate analysis showed that VCT processed beef aroma profiles were sorted into two groups, one included samples stored for up to 20 days and the other included samples with 34 to 45 days of storage. WOF odour standard samples were recognised to have similar aroma as samples of the second group. Lipid oxidation results, measured by thiobarbituric acid reactive substances, showed an increment in oxidation level for samples stored for 34 days or more (P<0.05). This study shows that electronic nose technology can be applied to WOF odour identification and classification in VCT beef meat, complementing chemical and sensory techniques used in this field.     

pH值对牛肉酶解物美拉德产物风味特性的影响

本研究旨在探讨pH值(5.0~6.5)对牛肉酶解物美拉德反应产物(enzymic beef hydrolysate Maillard reaction product,EBH-MRP)风味特性的影响。结果表明:随着pH值的增加,EBH-MRP的感官特性主要从肉香、咸鲜味向烤香、苦味发展,对空白鸡汤的鲜味提升作用由强至弱,醇厚感提升作用稳步增强。苦味与烤香间存在显著的正相关关系,过度的烤香不仅掩盖肉香,还意味着苦味物质的生成,抑制味蕾对鲜味、鲜味提升作用及醇厚感的感知强度。结合风味物质含量的测定发现,肉香既不与重要前驱物半胱氨酸(Cys)的参与量具有相关性,也不与关键肉香味物质的含量具有相关性。说明肉香的感知是多类气味物质共同调控的结果,且生成机制极为复杂。此外,含氮杂环气味物质的总含量与烤香间有着极显著的正相关关系;大于3 000 D的糖肽交联产物对苦味具有一定贡献;适当的肽降解作用有利于醇厚感的提升。     

The effect of free fatty acids on the odour of pork investigated by sensory profiling and GC-O-MS

The precursors for fried flavour in pork include fatty acids, carbohydrates and amino acids. The aim of this study was to investigate the effect of free fatty acids on the odour of a pork model system and to identify important aroma compounds detected by GC-O. The odour of heat-treated minced pork to which a free fatty acid had been added was assessed by a sensory panel. The following fatty acids were compared with a control meat sample: C18:1, C18:2ω6, C18:3ω3, C18:3ω6, C20:4ω6 and C22:6ω3. The fatty acids were added at either 40 or 100 times the natural level present in the minced pork. The addition of fatty acids reduced the intensity of the meaty odour. C18:2ω6 resulted in an oily odour, while C18:3ω3 and C22:6ω3 resulted in a fishy odour. The effect of C18:1, C18:3ω6 and C20:4ω6 on the odour was smaller. An aroma analysis was performed by GC-O-MS, using eight panellists, on a control meat sample and on meat samples after addition of C18:2ω6, C18:3ω3 and C22:6ω3. Sixty-two odour-active areas were detected. An underlying compound was identified in 38 areas. A large number of long-chain aldehydes, alcohols and ketones were detected in the sample to which C18:2ω6 had been added, and this might explain the oily odour of these samples. Especially 1-penten-3-ol was detected in the samples to which C18:3ω3 and C22:6ω3 had been added, and this might explain the fishy odour of these samples.     

基于PLSR鹰嘴豆蛋白美拉德风味肽最适底物的研究

本实验以鹰嘴豆蛋白为原料,通过双酶定向酶解制备一系列不同水解度(DH%)鹰嘴豆蛋白酶解液,以此为底物采用描述性感官分析(DSA)和气质联用技术(GC-MS)分析比较经模式美拉德反应体系制备所获得风味肽产品的风味特征,以期获得美拉德风味肽最适鹰嘴豆蛋白酶解体系。结果表明:由不同DH%鹰嘴豆蛋白酶解液为底物制备的美拉德风味肽产品在感官属性和形成的香气成分上呈现显著差异,当添加DH%为23.03%~26.02%的酶解液制得的美拉德风味肽其所形成的香气种类和数量相对较多,同时呈现明显的肉味、鲜味和较长的持续感。结合偏最小二乘回归(PLSR)对其香气物质、感官分析数据和电子鼻响应值进行相关性分析,进一步表明DH%为23.03%~26.02%的鹰嘴豆蛋白酶解液可作为风味肽产品热反应最适反应底物。     

Sensory aroma from Maillard reaction of individual and combinations of amino acids with glucose in acidic conditions

The aroma produced in glucose–amino acids (individual and in combination) Maillard reaction, under acidic conditions at 100 °C were determined and compared by trained panellist. Proline produced pleasant, flowery and fragrant aroma. Phenylalanine and tyrosine produced dried roses aroma. Alanine produced fruity and flowery odour, while aspartic acid and serine both produced pleasant, fruity aroma. Arginine, produced a pleasant, fruity and sour aroma at pH 5.2, but not at its natural pH. Glycine, lysine, threonine and valine produced a pleasant caramel-like odour. Isoleucine and leucine gave off a burnt caramel aroma. Methionine developed a fried potato odour. Cysteine and methionine produced savoury, meaty and soy sauce-like flavours. A combination of these amino acids produced different types of aroma, with the stronger note dominating the odour of the mixture. This study will help the prediction of flavour characteristics of hydrolysates from different protein sources.     

Identification and origin of the character‐impact compounds of raw oyster Crassostrea gigas

The French consume large amounts of raw oysters. The study of the aroma of oyster Crassostrea gigas is of economic interest because it is a good method of checking the sensory quality. Aromas were extracted by vacuum steam distillation at 20 °C using whole oyster flesh. This extract presented similar sensory characteristics to raw oyster. The odour‐active compounds were characterised by gas chromatography coupled with olfactometry using a panel of 10 judges trained in seafood aroma recognition. Fifty‐nine volatile compounds were identified in oyster aroma extract. Among these, 25 were responsible for the overall odour of raw oyster. Four compounds identified in oysters were characterised by fresh and marine odour: 3‐(E)‐hexen‐1‐ol, decanal, 2‐undecanone and 3,6‐(E,Z)‐nonadien‐1‐ol. Some compounds were identified for the first time in oysters: 4‐(Z)‐heptenal (white boiled fish odour), which comes from n‐3 polyunsaturated fatty acid oxidation, and 3‐octanol (moss and sulphury odour), 2‐nonanol (cucumber odour) and octanoic acid, which arise from n‐6 polyunsaturated fatty acid oxidation. © 2002 Society of Chemical Industry     

Characterisation and threshold measurement of aroma compounds contributing to the quality of Honkaku shochu and Awamori

Honkaku shochu and Awamori are traditional Japanese spirits. The detection and thresholds of 16 compounds in these spirits were determined so as to understand the compounds contributing to the aroma characteristics of Honkaku shochu and Awamori. The odour activity values calculated using detection thresholds suggested that 14 compounds affect the quality of Honkaku shochu and Awamori. The odour activity values of β-damascenone and rose oxide were much higher in sweet potato shochu and these two compounds are considered to contribute to the characteristics of sweet potato shochu. Similarly, the odour activity value of 1-octen-3-ol was higher in Awamori than in the other categories, suggesting that 1-octen-3-ol produces the characteristic aroma of Awamori. In addition, the sensory attribute terms of 16 compounds are summarised. © 2019 The Institute of Brewing & Distilling     

Changes in volatile compounds and sensory quality during toasting of Spanish almonds

Toasting is one of the most important unit operations in turrón manufacture. The main objective was to study changes in volatile compounds and sensory odour and aroma during almond toasting. Two almond cultivars were studied 'Comuna' and 'Marcona'. CIE L * a * b * colour, instrumental aroma and sensory odour and flavour were evaluated in toasted almonds (200 °C: the most popular temperature for almond toasting in convection ovens) at five times from 12 to 23 min. The main pyrazines found were: 2,5-dimethylpyrazine, 2-ethyl-3-methylpyrazine, 2-methylpyrazine and 2,4-dimethyl-3-ethylpyrazine. Pyrazines, furans and pyrroles concentrations in 'Comuna' almonds were higher than in 'Marcona' samples at the end of toasting; however, sensory analysis showed that 23 min were too long for 'Comuna' almonds (burnt notes) and shorter toasting time must be applied. Based on both instrumental and sensory colour and aroma data, the recommended toasting time at 200 °C in convection ovens for 'Comuna' and 'Marcona' almonds should be 20 min.     

Characteristic properties of Muhlama

The composition of muhlama, which consists of corn flour, butter, water, salt and either string, golot or minced curd cheese, was examined to determine its essential characteristics. Muhlama samples were collected from prominent Black Sea restaurants in Istanbul for sensory analysis and an evaluation of physicochemical properties. Sensory analysis was conducted on properties including appearance, texture, odour, flavour and aroma. Physicochemical properties such as pH, moisture, fat, fatty acid composition (saturated and unsaturated), protein, ash and energy were measured. The results of the physicochemical properties revealed pH (5.65), moisture (55.85 g/100 g), fat (13.6 g/100 g), fatty acid composition (saturated fatty acid: 1013.34 mg/kg, and unsaturated fatty acid: 286.14 mg/kg), protein (19.4 g/100 g), ash (1.34 g/100 g) and energy (239.18 kcal/100 g). The sensory analysis showed samples of light yellow colour, uniform and shiny in appearance, and a consistency in soft and smooth structure. The product had a unique flavour and aroma with the chemical structure of high energy value of the nutrient elements.