高温风干成熟工艺对风鸭风味物质的影响

为研究高温风干成熟工艺对风鸭风味物质的影响,采用固相微萃取结合气相色谱/质谱联用技术(SPME-GC/MS)检测了原料、腌制、风干24、48、72、96 h不同工艺阶段风鸭中挥发性风味化合物的种类及相对含量,并利用主成分分析方法分析影响风鸭风味的主要因子。共检测到110种挥发性风味成分,分别为醇类(38)、烃类(24)、醛类(19)、酮类(9)、胺类(7)、呋喃类(4)、酯类(3)、酸类(2)、含硫化合物(2)、醚类(1)和含氮化合物(1)。第一主成分主要由醛、醇类和甲基酮构成,第二主成分主要由烃、醇和醛等组成。风鸭风味的形成受脂肪氧化分解、蛋白质降解及微生物共同作用的影响,通过控制加工工艺参数可以调控高温成熟风鸭风味的形成。     

高温风干对风鸭品质及脂质氧化的影响

通过对高温风干和低温风干鸭胸肉理化指标、TBARS及产品感官品质、挥发性风味物质的比较,研究高温风干工艺对风鸭品质特性及脂质氧化的影响.结果显示:高温风干可以显著加速风鸭水分散失、Aw下降及盐分积累速度(p＜0.05),显著促进a*值下降(P＜0.05),对质构影响不显著;高温风干组TBARS值极显著高于对照组(p＜0.01),温度对脂质氧化速率影响极显著;挥发性风味物质中醛类物质含量(达54.85％和67.1％)显著高于原料,己醛、壬醛、3-甲基正丁醛和戊醛是醛类物质的主体成分,是形成风鸭风味品质的一类重要物质;高温风干生成更多的酸、酮类物质可能是脂质过氧化产生酸败味的重要成分.     

猪肉中风味物的研究进展

风味是影响猪肉品质的重要指标之一,本文综合叙述了猪肉中风味物的前体物质以及呈味成分,呈味成分的形成途径和影响其形成的因素(脂质氧化、美拉德反应和斯特勒克降解反应、硫胺素降解是肉的风味形成的主要三条途径),并进一步提出了风味的调控,这些对于猪肉的保鲜和加工具有重要的指导意义.     

贻贝热泵干制过程中的品质变化研究

为研究贻贝热泵干制过程中的品质变化,对其蛋白质变性、脂肪氧化程度和风味与色泽变化等进行了研究。研究表明贻贝在干制过程中蛋白质主要在55~60发生变性,蛋白纤维紧缩和氢键的形成使得组织弹性和硬度增加,电镜观察到其肌纤维间隙减小、蛋白凝聚程度增加,质构测试结果验证了其咀嚼性的提升;TBARS值表明其脂肪氧化随着干制进程呈现先加剧后减缓的趋势,伴随着蛋白质和脂肪发生的化学变化而进行的风味物质含量变化形成了其独特的风味,呈鲜的谷氨酸、天冬氨酸和呈甜的甘氨酸和丙氨酸等氨基酸游离程度增加,使得干制品具有较好的鲜味,GC-MS结果说明醛类与烃类等其他物质之间在干制过程中发生了相互转化,挥发性风味物质的含量变化消除了海腥味,形成干品独特的氧化烘香气味;贻贝经过干制后颜色加深,得到以棕褐色为主的干制品,热泵干制能够得到色、香、味等各方面品质较好的贻贝干品。     

鲟鱼肉冷藏期间腥味及品质变化

为探明鲟鱼肉冷藏过程腥味形成规律及其影响因素,文中研究分析了鲟鱼背部、腹部和尾部肌肉组织品质指标和鱼腥味变化情况。结果表明:冷藏前期3个部位的鱼肉挥发性盐基氮(TVB-N)值增加缓慢,5 d后TVB-N呈现快速增长,表明鱼肉开始出现微生物腐败迹象。表征脂肪氧化程度的硫代巴比妥酸值(TBARS)冷藏前期增幅缓慢,第3天后增幅加速,脂肪氧化速度加快;冷藏期间脂肪氧化酶(LOX)活性呈先升高后降低的趋势;冷藏2 d后鱼体主要不饱和脂肪酸下降幅度加快,挥发性物质总量增加明显。对鱼肉冷藏期间挥发性物质风味特征进行分类分析表明,鱼肉冷藏过程中以鱼腥味、青草味及脂肪氧化气味变化为主,其中以鱼腥味变化最为突出。将贮藏过程中鱼肉品质指标与鱼腥味变化规律进行分析发现,鱼腥味等异味的产生主要是由脂肪氧化所致,后期微生物腐败对鲟鱼肉风味变化起协同作用。     

不同炒制时间对燕麦挥发性风味物质形成的影响

采用顶空固相微萃取-气相色谱-质谱联用技术对不同炒制时间的燕麦挥发性风味物质进行测定分析,初步建立脂肪氧化程度与燕麦风味物质形成的关联性。结果表明：在整个炒制过程中,燕麦中烃类、醛类、醇类物质的含量随炒制时间的增加呈先增加后减少的趋势,而吡嗪类物质含量在炒制25 min后显著增加。聚类分析结果表明,炒制前期(≤15 min)与炒制中后期(≥25 min)的燕麦风味区分明显。相对香气活度值、主成分分析表明,炒制前期的特征风味物质以醛类为主,包括癸醛、(E)-2-壬烯醛、壬醛、苯甲醛等,呈果香、甜香、花香、弱油脂香;而炒制中后期的特征风味物质以吡嗪类、醛类为主,呈焦香味、果香味。炒制初期燕麦中不饱和脂肪酸含量由84.41%降至81.72%,炒制中后期脂质氧化产物逐渐增多、氧化程度逐渐加深,茴香胺值从0.73升高到4.49后开始降低,硫代巴比妥酸值从0.023 mg/kg升高到0.039 mg/kg后保持不变,炒制前中期(＜35 min)脂肪氧化程度与醛类等重要风味物质的含量呈正相关。     

发酵香肠风味物质的来源和形成

发酵香肠在发酵和成熟过程中发生的几种化学变化决定了终产品的风味和滋味。风味的来源包括蛋白质分解、脂肪氧化、以及微生物对三大营养物质的代谢等,其中脂肪和蛋白质的代谢是风味物质的主要来源。挥发性和非挥发性风味物质的种类和二者的比例决定发酵香肠的典型风味。概述了发酵香肠中风味物质和形成机理,并阐述影响风味形成的主要因素。     

固相微萃取与气质联用法分析杨梅汁饮料中不良风味成分

为了探讨杨梅汁饮料中的不良风味成分,采用固相微苹取技术结合气质联用对杨梅汁饮料的风味成分进行了定性定量分析。经对比正常与异常风味的杨梅汁饮料的风味组成,杨梅汁饮料风味异常表现如下:酯类和反-丁子香烯等杨梅特征风味物质含量降低;呈现酒精味的乙醇、3-甲基丁醇含量增加;呈现腐败味的己酸、壬烯含量增加;多酚氧化和脂肪氧化产生的醛类物质增多。     

比较2种蓝圆鰺腌干工艺中脂质氧化与挥发性风味物质形成的关系

为探明鱼类腌制过程脂质氧化与特征风味物质形成的关系,以蓝圆鰺(Decapterus maruadsi)为原料,采用2种不同的腌干方法,传统高盐(traditional high salt,HS)法和低盐乳酸菌(low-salt lactic acid fermentation,LAF)法对其进行加工。测定2种工艺的腌干鱼加工过程中不同加工阶段脂肪氧合酶(lipoxygenase,LOX)、过氧化值(peroxide value,POV)、硫代巴比妥酸(thiobarbituric acid reactive substances,TBARS)值、主要挥发性风味物质的变化规律,利用Person相关系数分析2种工艺加工过程中脂质氧化、挥发性风味物质形成规律及两者之间的关系。结果表明:LOX活性均呈现先增加后降低趋势,除烘干末期之外酶活性HS法大于LAF法(P0.05),成品中LOX活性较鲜鱼分别增加了25%(HS)、34.8%(LAF);POV、TBARS值变化趋势与LOX变化趋势基本相同,烘干后期POV急速下降;成品中主要挥发性风味物质为醛、酮、烃、醇类物质,挥发性风味物质主要形成于烘干期间;LAF法生产的产品在HS法产品风味基础上增加了花香味;LOX与脂肪的氧化、风味物质形成之间具有一定的正相关性且脂肪氧化对风味物质的形成具有重要作用;LAF法更利于LOX发挥酶活力,促进风味物质特别是醛类物质的形成。     

蛋黄粉中关键香气活性物质分析及其在储藏过程中的香气变化

为探究蛋黄粉在储藏过程中的风味变化,本文采用SPME/GC-O-MS法对不同储藏时间蛋黄粉的挥发性化合物进行测定,并确定关键气味活性物质,利用主成分分析法(PCA)分析不同储藏时间样品的关键气味活性物质主要差异。结果表明:在蛋黄粉样品中,最终鉴定出31种挥发性成分,其中醇类9种,醛类7种,酮类9种,酯类1种,杂环类5种等。在这31种香气成分中,能够通过嗅闻仪被检测到的气味成分为2-甲基丁醛(可可粉味)、异戊醛(麦芽味)、正己醛(青草味)、1-辛烯-3-酮(蘑菇味)、2-壬酮(热牛奶味)、3,5-辛二烯-2-酮(脂肪味)、乙酸丙酯(奶酪味)、2-戊基呋喃(青豆味)、2,5-二甲基吡嗪(烤坚果味)、5-甲基-2-乙基吡嗪(果香味),由于它们的重要贡献作用,因此被鉴定为蛋黄粉的关键气味活性物质。对储藏时间和关键气味活性物质进行主成分分析(PCA)并结合相对浓度变化得知,在储藏初期,即0~2个月,对蛋黄粉具有贡献作用的香气物质较为单一,主要为吡嗪和醛类物质,随着储藏时间的增加,蛋黄粉中气味物质的种类和浓度均有所增加,主要表现为醇类,酮类物质的增加,使蛋黄粉具有更为丰富的风味轮廓。以上结果表明,脂肪氧化与美拉德反应是蛋黄粉整体风味发生变化的重要原因,脂肪氧化易带来不利影响,美拉德反应产物大多起到协调风味的作用,因此,为提高蛋黄粉货架期稳定性,抑制脂肪氧化和促进美拉德反应生成是可以采取的措施。     

酱鸭强化高温风干成熟工艺优化

以麻鸭为试验原料,通过酱腌风干成熟制作风干酱鸭,分析加工过程中脂肪氧合酶（lipoxygenase,LOX）酶活、硫代巴比妥酸（thiobarbiturie acid reactive substance,TBARS）反应底物值和过氧化值（peroxide value,POV）,研究强化高温风干处理对酱鸭加工过程中脂质...     

THE DEVELOPMENT OF LIQUID MALT*

The preservation of green malt by hot air drying is the most usual form of kilning. This not only ensures biological stability but also allows some flavour adjustment both by the evaporation of “green” flavours and the development of “biscuit” flavour on curing. A survey is now made of the development of a process of liquid kilning, in which starch conversion and extraction follows modification and precedes evaporative preservation and “green” flavour removal.     

Use of healthier fats in biscuits (olive and sunflower oil): changing sensory features and their relation with consumers' liking

The aim of this study was to evaluate consumer acceptability of biscuits when saturated fat was replaced by olive or sunflower oil and to determine the sensory characteristics responsible for changes in acceptability. Ninety seven consumers evaluated the acceptability of six biscuit samples varying in the fat source (dairy shortening, olive oil and sunflower oil) and fat content (10.6% and 15.6%). Using a Check All That Apply question (CATA), consumers also evaluated sensory properties of biscuits. Results indicated that the replacement of saturated fat (dairy shortening) by vegetable oils had an effect on biscuit acceptability which depended on biscuit fat content. According to biscuits' acceptability data, three different clusters of consumers were identified. By using a multiple factor analysis, the relationship among sensory CATA data and acceptability of each cluster explained the different acceptability patterns of consumers. For most of consumers acceptability was related to attributes “crispy”, “easy to chew” and “biscuit flavour” which, for one group were perceived in shortening biscuits and, for another in both olive and shortening biscuits. However, for the third group of consumers, acceptability was only related to flavour attributes like “roasted flavour” or “biscuit flavour” that were perceived in vegetable oil biscuits which were the preferred biscuits while, shortening biscuits were disliked and perceived as having an “off flavour”.     

风鸭加工过程中肌内和皮下脂肪水解特性研究

研究了控温控湿现代化工艺加工中风鸭肌内和皮下脂肪的甘油酯、磷脂、游离脂肪酸、理化指标的变化规律及内在相关性。采用三氯甲烷-甲醇溶液提取脂肪,固相萃取法分离脂肪,通过毛细管气相色谱分析游离脂肪酸的含量。结果显示:肌内脂肪中磷脂和游离脂肪酸含量比皮下脂肪变化显著,肌内脂肪水解是风鸭脂类物质变化的主体;肌内游离脂肪酸尤其油酸(18∶1)和亚油酸(18∶2)主要来自于肌内磷脂的降解,而皮下甘油酯和磷脂对皮下游离脂肪酸积累都有一定的贡献;棕榈酸(16∶0)、硬脂酸(18∶0)、油酸(18∶1)和亚油酸(18∶2)是风鸭游离脂肪酸主体成分。     

Effects of using whey and maltodextrin in white cheese powder production on free fatty acid content,nonenzymatic browning and oxidation degree during storage

Use of maltodextrin and whey improves the physical properties of spray-dried cheese powder and, as cheese replacers, they decrease the raw material costs. However, it is necessary to evaluate their effects on the chemical quality and sensory properties of the product. Three powders, control (CON), whey-added cheese powder (WACP), and maltodextrin-added cheese powder (MACP) were produced to determine free fatty acid (FFA) content, degree of nonenzymatic browning, oxidation, and sensory (flavour) changes during 12 months' storage. In the emulsion preparation and drying process, total volatile FFAs decreased up to 9% and 53.5%, respectively, with higher decrease in CON than in WACP or MACP. Although whey increased oxidation degree of powder, oxidised flavour could not be perceived until the ninth month of storage. Maltodextrin slightly decreased cheese flavour and overall impression scores. There was no difference detected in the powders for scorched flavour.     

Relationships between sensory attributes and the volatile compounds,non-volatile and gross compositional constituents of six blue-type cheeses

Relationships between odour and flavour attributes of six blue-type cheeses and their volatile compounds, free amino acids (FAA), free fatty acids (FFA) and gross compositional constituents were determined. Relationships were also determined between texture attributes and gross compositional constituents. Fifteen assessors described the odour, flavour, appearance and texture profile of cheeses. Volatile compounds were isolated using a model-mouth apparatus. FAA, FFA and gross compositional constituents were determined using standard methods. Using Partial Least Squares Regression two odour and five flavour attributes were found to correlate with subsets of volatile compounds, FAA, FFA and gross compositional constituents. For example, “mouldy” flavour was positively correlated with the concentrations of pH 4.6-soluble nitrogen and 2-pentanone, 2-heptanone, 2-octanone and 2-nonanone. Three texture attributes were found to correlate with subsets of gross compositional constituents. For example, “crumbly” texture was positively correlated with concentration of fat and protein and negatively correlated with levels of moisture in the non-fat substance and moisture.     

Flavour studies with fish meals and with fish oil fractions in broiler diets

Fish meals extracted with ethanol, benzene and/or warm water or acidified water were included in diets for broilers at 20 % levels, while in some instances certain amines, phospholipids from the fish oil extracted from fish meal (here called “residual” fish oil) and triglycerides from such fish oil were added to broiler diets singly or in different combinations. The experimental diets were given to broilertype chickens from their fifth week until they were slaughtered when 81/2 weeks old. Carcasses from the different treatment groups were subjected to organoleptic evaluation and the fatty acid make-up of the fat in the carcasses and of the oils in the fish meals, determined by gas chromatography. Carcasses of chickens which received diets containing fish meal extracted with the fat solvents consistently had a chicken flavour. When the diets contained fish meal extracted with warm water or a warm, weak, acid solution the carcasses had a neutral flavour. Unextracted fish meal and the triglyceride fraction of fish oil (at a 2.0 % level) in the diet invariably produced carcasses with a “fishy” taint. The phospholipid fraction of “residual” fish oil had no effect on carcass flavour while additional amines (trimethylamine, ethanolamine and choline) in the diet in most instances aggravated the foreign taint. The high correlation between flavour score and the levels of certain highly unsaturated fatty acids in the chicken carcasses was confirmed.     

The influence of slaughter weight on the stability of pork sides in frozen storage

Eight groups of six pigs were obtained, two sources of supply × meal-fed and swill-fed × “light” (37 to 35 kg) and “heavy” (66 to 88 kg). The pigs were slaughtered, weighed, graded, chilled, split and the sides wrapped in stockinet and polyethylene, frozen in a room at below ?30 °C and stored commercially at below ?20 °C. Corresponding sides were withdrawn after four and nine months, weight losses were measured and samples cooked and submitted to a panel for appraisal of any differences in flavour. Samples of the fat of each side were also investigated chemically for extent of oxidation of the fat. There were no significant differences in flavour attributable to weight range, with either meal- or swill-feeding nor any chemical indication of oxidative rancidity.     

Far infrared assisted refractance window drying of apple slices: Comparative study on flavour,nutrient retention and drying characteristics

In the present investigation, far infrared (FIR) assisted refractance window (RW) drying (FIR+RW) of apple slices (2 and 5 mm) was evaluated in comparison with RW and hot air (HA). FIR+RW reduced drying time by 50 and 69% compared to RW and HA, respectively. Also, FIR+RW drying retained a significantly higher amount of phenolics, flavonoids, ascorbic acid, and antioxidant activity, as compared to HA. Increase in FIR temperature from 50 to 60 °C reduced drying time by 10–19% without having any deleterious effect on quality. Colour, flavour, and microstructure of FIR+RW dried slices were comparable to that of RW. Nearly 46% saving in energy consumption was observed for FIR+RW drying compared to HA. Results suggested that FIR+RW drying can be explored as a potential technique for drying of fruits in a shorter time, with better retention of flavour, nutrients and also enhance energy efficiency.Industrial relevanceDried apple slices have a good market potential as a raw material in many processed foods and can be an alternative to deep fat fried chips for health-conscious consumers. This work focuses on assessing the efficacy of developed FIR assisted RW drying system in terms of drying time, energy, and quality attributes (colour, nutritional, flavour, microstructure) in comparison with conventional drying methods. The results showed that FIR assisted RW drying technique has great industrial potential in saving processing time as well as energy with better retention of quality of dried products.