铜、锌、铁清料法加工溏心皮蛋的比较研究

在用NaOH清料法直接加工皮蛋过程中,采用了CuSO4·5H2O、ZnSO4·7H2O和FeSO4·7H2O三种微量辅料,并对单独或混合使用这些微量辅料加工溏心皮蛋的优劣进行了比较。研究表明,当用NaOH代替Na2CO3和CaO直接加工皮蛋时,“铜法”、“铜锌混合法”和“铁锌混合法”效果最优,“锌法”对加工时间要求严格且效果略次,“铁法”不能成功。     

Age-associated variation in sensory perception of iron in drinking water and the potential for overexposure in the human population

Humans interact with their environment through the five senses, but little is known about population variability in the ability to assess contaminants. Sensory thresholds and biochemical indicators of metallic flavor perception in humans were evaluated for ferrous (Fe(2+)) iron in drinking water; subjects aged 19-84 years participated. Metallic flavor thresholds for individuals and subpopulations based on age were determined. Oral lipid oxidation and oral pH were measured in saliva as potential biochemical indicators. Individual thresholds were 0.007-14.14 mg/L Fe(2+) and the overall population threshold was 0.17 mg/L Fe(2+) in reagent water. Average thresholds for individuals younger and older than 50 years of age (grouped by the daily recommended nutritional guidelines for iron intake) were significantly different (p = 0.013); the population thresholds for each group were 0.045 mg/L Fe(2+) and 0.498 mg/L Fe(2+), respectively. Many subjects >50 and a few subjects <50 years were insensitive to metallic flavor. There was no correlation between age, oral lipid oxidation, and oral pH. Standardized olfactory assessment found poor sensitivity for Fe(2+) corresponded with conditions of mild, moderate, and total anosmia. The findings demonstrate an age-dependent sensitivity to iron indicating as people age they are less sensitive to metallic perception.     

Anthocyanin,phenolic composition,colour measurement and sensory analysis of BC commercial red wines

This research established a database of analytical values associated with 173 commercial red wines from 7 vintages (1995–2001), 4 varieties (Pinot noir, Merlot, Cabernet Franc, Cabernet Sauvignon) and 13 vineyard locations within BC. Wines were analyzed for sulfur dioxide, pH, titratable acidity, phenolics, tartaric esters, flavonols, as well as copigmented, monomeric, polymeric, and total anthocyanins. Colour was evaluated using colour density, hue, and L, a¹, b¹ and chroma measurements. The sensory astringent qualities were characterized on a subset of 78 wines, using a panel of 12 judges. The panel evaluated the magnitude of the astringency, astringent aftertaste, oakiness and bitterness, as well as 3 astringent sub-qualities (surface roughness, drying, puckering). Data were analyzed by analysis of variance, principle component analyses, and canonical discriminant analyses to track the influence of variety, vintage and vineyard location. Trends were observable despite large variation in winemaking techniques. Red colour, colour density, copigmented, monomeric, polymeric and total anthocyanins were lowest in Pinot noir and highest in Cabernet Sauvignon wines. Younger wines had higher concentrations of copigmented, monomeric, and total anthocyanins than did older wines. Canonical discriminant analysis of the analytical and sensory determinations were successful in distinguishing the wines according to where the grapes were grown.     

Determination of geosmin and 2,4,6-trichloroanisole in white and red Austrian wines by headspace SPME-GC/MS and comparison with sensory analysis

This paper describes the development and application of a fast and simple headspace solid phase microextraction GC–MS method for simultaneous determination of geosmin and 2,4,6-trichloroanisole (2,4,6-TCA), two main contributors to off-flavors in wine. The compounds were adsorbed onto a polydimethoxysiloxane (PDMS) fiber at 35 °C for 40 min without prior equilibration, thermally desorbed and analyzed by GC–MS in the selected ion monitoring mode. The parameters for adsorption onto and desorption from the fiber were optimized. This method was applied to analysis of 118 Austrian white and red wines, which were also characterized by sensory analysis. Geosmin was above the limit of detection (0.5 ng/L) in 110 wines (93%) and additionally quantified (>2 ng/L) in 65 wines (55%). It could be detected in wines of each off-flavor (moldy, corky, damp, musty, rotten, woody, grassy) in concentrations up to 16.7 ng/L and even in 90% of the sensorially faultless wines (up to 6.5 ng/L). On the other hand, 2,4,6-trichloroanisole was detected only in 24 wines (20% of all investigated wines) and above the limit of quantitation (2 ng/L) only in 5 wines (4%) sensorially classified as corky; corky and moldy plus other defects; or faultless in concentrations up to 14.3 ng/L. These results show that geosmin is more prevalent than 2,4,6-TCA and that chemical analysis is required especially when other wine characteristic flavors cover beginning off-flavors.     

Bioactive compounds and sensory attributes of sour cherry puree sweetened with natural sweeteners

The aim of this study was to describe a phytochemical profile, including phenolic compounds, antioxidant capacity, colour and sensory quality attributes (colour, aroma, consistency, sweetness intensity and desirability) of a sour cherry puree (SCP) supplemented with different natural sweeteners. Supplementation of SCP with the sweeteners only slightly affected polyphenol content, which was by 9% (SCP with steviol glycosides) to 26% (SCP with erythritol) lower than in pure SCP. Furthermore, the products with natural sweeteners were characterised for the lowest antioxidant activity than the SCP sample, especially in SCP with erythritol and xylitol. In addition to having high content of polyphenols and high antioxidant activity, these products were also attractive to consumers, especially when supplemented with xylitol, palm sugar or sucrose, but not with Luo Han Kuo fruit, which was found unacceptable. The results showed that most of the obtained SCPs had very promising and interesting phytochemical properties and sensory profiles.     

感官评价和GC-MS结合偏最小二乘回归法分析酚类化合物对腊肉烟熏风味的贡献

通过探究酚类化合物对腊肉烟熏风味的影响,确定关键烟熏风味物质。以6个烟熏腊肉和2个风干腊肉为研究对象,分别采用定量描述分析法描述气味特征和固相微萃取-气相色谱-质谱联用技术分析挥发性成分。结果表明,烟熏腊肉具有烟味、木味、灰烬味、刺鼻等4种烟熏风味,但风干腊肉不具有烟熏风味。6个烟熏腊肉样品中共鉴定出苯酚等6种烷基酚类和愈创木酚等6种愈创木基型酚类,每个样品中分别含有3～10种。2种风干腊肉中均未鉴定出酚类化合物。偏最小二乘回归(partial least-squares regression,PLSR)分析发现,除了4-甲氧基苯酚,苯酚、愈创木酚等酚类化合物对烟熏风味有较大的贡献。该研究确定了酚类化合物是腊肉中的关键烟熏风味物质,为改良食品的烟熏风味和开发烟熏液提供了理论依据。     

巧克力质地的感官评定和仪器测定之间的相关性研究

通过感官评定和仪器测定(穿刺、三点弯曲和TPA)三种方法对五种巧克力的质地进行了研究,通过二者的相关分析得出了感官评定指标以仪器测定为变量的线性回归方程,即预测模型,并对预测模型进行了验证.本研究为利用质构仪代替感官评价巧克力质地品质提供了理论依据.     

Analytical comparison and sensory representativity of SAFE, SPME, and Purge and Trap extracts of volatile compounds from pea flour

Pisum sativum is of great economic and nutritional interest due to its protein content. Nevertheless, pea products are underused as a protein source in human food because of their strong beany flavour. Therefore, the objective of this study was to select an efficient and representative method to extract volatile molecules of pea flour. In the first step, three extraction methods were chosen: solid phase micro extraction (SPME); Purge and Trap extraction and solvent assisted flavour evaporation (SAFE). The corresponding extracts were analysed by gas chromatography coupled with mass spectrometry. In the second step, the sensory representativity of the extracts was assessed either by direct gas chromatography-olfactometry for SPME and for Purge and Trap extracts, or by sniffing for the aqueous SAFE extract. It appeared that SAFE extraction was the most suitable method because of its good extraction capacities and its high sensory representativity of the global odour of pea flour.     

A comparative study of the nutritional values,volatiles compounds,and sensory qualities of pea pastes cooked in iron pot and clay pot

In the current study, the nutritional values, volatiles compounds, and sensory qualities of pea pastes cooked in iron pot and clay pot were compared. Results showed that the iron pot‐cooked pea pastes contained profoundly more iron, total sugar, and starch than the clay pot‐cooked ones, and the effects were found related to iron ion by comparing the results between clay pot‐cooked pastes with and without iron ion addition. Samples prepared with the two utensils demonstrated similar contents of protein, polyphenol, and tannin, but differed in the composition of some volatile alcohols, alkanes, aldehydes, ketones, esters, and organic acids. The clay pot‐cooked samples had higher score of “color,” “mouthfeel,” “taste,” and “overall quality” than the iron pot‐cooked pastes. In conclusion, iron pot can allow the production of iron‐enriched pea pastes whose sensory qualities are remarkably lower than those of the clay pot‐cooked samples but are still in the acceptable range.

Practical applications

Iron utensil plays an important role in modern food industry due to its durability and convenience to handle. Cooking with iron pot is a simple and useful method of dietary iron fortification for the prevention of iron‐deficiency anemia in developing countries. Pea paste is a popular legume food with high nutritional value and good palatability. Traditional pea paste producers believe cooking with clay pots can give rise to product with more desirable features than using iron pots. However, there were no scientific evidences regarding the effects of cooking utensils on pea paste qualities. It has been proved in the current study that iron pot can allow the production of iron‐enriched pea pastes whose sensory qualities are remarkably lower than those of the clay pot‐cooked samples but are still in acceptable range.     

利用铁、铜间相互作用减轻烤烟铜毒害的研究

采用温室溶液培养方法,研究利用铁、铜间相互作用减轻烤烟铜毒害。试验结果显示,K326品种Cu2 毒害临界值在1.0-1.2mg/L之间。在低浓度Cu2 (0.1-1.2mg/L)时,烟株吸铁总量增加;高浓度Cu2 (≥1.4mg/L)时,吸铁总量降低。溶液中添加过量的Fe3 (5.61mg/L和11.23mg/L)后,烟株的吸铁量显著增加,而吸铜量明显减少,铁和铜元素由根系向地上部的转运增加,生物量增加4-7倍,可以明显减轻Cu2 的毒害。因此,利用铁、铜间相互作用减轻烤烟铜毒害是可行的。     

Zinc, iron and copper contamination in home-produced alcoholic drinks

The contamination of home-brewed alcoholic drinks with zinc, iron and copper is fairly widespread. It is largely unrelated to the material fermented but usually depends on the type of vessels used during production.     

白兰地主要香气物质感官分析

对烟台张裕X0白兰地的主要香气成分进行感官分析.采用GC-MS鉴定出107种挥发性的化合物.经气相色谱-闻嗅分析,只有39种主要香气活性成分,香气最强的物质有:"奶油"特征来自于双乙酰,"干草"特征来自于橙花叔醇,"草香"来自于Z-3-己烯-1-醇,"梨香"和"香蕉香"由两种乙酸甲基丁酯产生,"玫瑰香"由乙酸苯乙酯形成,"酸橙香"由里哪醇形成,"椽木香"由顺式-á-甲基-?-辛内酯形成.研究证明:白兰地橡木中存在多种香气成分,给白兰地带来特有香气.     

A comparison of warmed-over flavour in pork by sensory analysis, GC/MS and the electronic nose

Pork muscle samples (M. longissimus dorsi and M. psoas major) were obtained from pigs given one of 4 dietary treatments, (i) control diet, (ii) supplemental iron (300 mg iron (II) sulphate/kg feed), (iii) supplemental vitamin E (200 mg dl-α-tocopheryl acetate/kg of feed) and (iv) supplemental vitamin E+supplemental iron. Warmed-over flavour (WOF) was evaluated by a trained sensory panel (n=8) for the four treatments cooked and refrigerated at 4?°C for up to 5 days. Gas chromatography mass spectrometry (GC/MS) and Electronic nose analysis was performed on a subset of the full design which included samples of M. longissimus dorsi, treatments (ii) and (iii) and M. psoas major with treatment (i) for 0 days of WOF development. Day 5 of WOF development was included in the subset and represented by samples of M. longissimus dorsi, treatment (iv) and M. psoas major, treatments (ii) and (iii). Bi-linear modeling was used to determine the correlation of GC/MS and electronic nose data to sensory data. Also, the reproducibility and reliability of electronic nose data was evaluated by repeating the analysis of samples in a different laboratory and with a time difference of approximately 11 months. Mean-centring was used to normalise the data from these two different electronic noise data sets. GC/MS data correlated to sensory data with specific compounds (e.g., pentanal, 2-pentylfuran, octanal, nonanal, 1-octen-3-ol and hexanal), proving to be good indices of oxidation in cooked samples of M. longissimus dorsi and M. psoas major. Electronic nose data correlated to sensory data and separated the sensory variation. The reproducibility of this data was high with the second set of samples being predictive of the first set.     

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.     

Novel approaches and application of contemporary sensory evaluation practices in iron fortification programs

Iron deficiency is the leading nutritional deficiency in the U.S. and the rest of the world, with its highest prevalences in the developing world. Iron fortification of food has been proposed as a strategy to reduce the high prevalence of iron deficiency. Poor consumer acceptance, unacceptable taste, and discoloration of the iron-fortified foods have been frequently listed as causes of unsuccessful iron fortification programs. An excellent prospect for improving consumer acceptance of iron-fortified foods is the incorporation of a thorough, organized, and unified approach to sensory evaluation practices into iron fortification programs for product optimization. The information gained from systematic sensory evaluation allows for the manipulation of the sensory attributes, and thus improvement of the sensory properties of the fortified food. However, iron fortification programs have not systematically measured the effect of fortification on the sensory quality of the food. Because sensory evaluation is an important criterion in successful iron fortification, an integrated approach is necessary. Therefore, nutritionists and sensory scientists should work closely with each other to select the most suitable sensory tests and methods. The objectives of this article are to: (1) critically review and discuss some traditional and contemporary approaches and applications of sensory evaluation practices in iron fortification programs, and (2) demonstrate the importance of incorporating a multidisciplinary, systematic sensory evaluation approach in iron fortification programs.     

Training of panellists for the sensory control of bottled natural mineral water in connection with water chemical properties

As bottled mineral water market is increasing in the world (especially in emergent and developed countries), the development of a simple protocol to train a panel to evaluate sensory properties would be a useful tool for natural drinking water industry. A sensory protocol was developed to evaluate bottled natural mineral water (17 still and 10 carbonated trademarks). The tasting questionnaire included 13 attributes for still water plus overall impression and they were sorted by: colour hues, transparency and brightness, odour/aroma and taste/flavour/texture and 2 more for carbonated waters (bubbles and effervescence). The training lasted two months with, at least, 10 sessions, was adequate to evaluate bottled natural mineral water. To confirm the efficiency of the sensory training procedure two sensory groups formed the whole panel. One trained panel (6 persons) and one professional panel (6 sommeliers) and both participated simultaneously in the water tasting evaluation of 3 sample lots. Similar average scores obtained from trained and professional judges, with the same water trademarks, confirmed the usefulness of the training protocol. The differences obtained for trained panel in the first lot confirm the necessity to train always before a sensory procedure. A sensory water wheel is proposed to guide the training in bottled mineral water used for drinking, in connection with their chemical mineral content.