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Extruded rice used as adjunct for beer fermentation was prepared using a single‐screw extruder. Extrusion pretreatment facilitated the saccharification and gelatinization of the rice starch as well as the formation of a glassy cellular structure, which was evaluated through scanning electron microscopy analysis. The effects of different parameters, including barrel temperature, water content, nozzle diameter and screw speed, as well as their interactions with rice expansion rate, were evaluated by response surface methodology to determine the optimum extrusion conditions. Extruded rice was acquired using the optimum extrusion parameters (water content, barrel temperature, screw speed and nozzle diameter of 22.4%, 103°C, 8 mm and 191.6 rpm, respectively), and the expansion rate reached 275.1%. The effect of the extruded rice adjunct on beer flavour compounds was investigated by comparing flavour compounds with those of traditional rice‐adjunct beer through sensitive static headspace–capillary gas chromatography spectrometry. The contents of esters, a highly important flavour group, in extruded‐rice‐adjunct beer (ethyl acetate, isoamyl acetate, ethyl hexanoate and ethyl caprylate at 11.6, 2.4, 0.2 and 0.3 mg L−1, respectively) were higher than those of the traditional rice‐adjunct beer. The contents of high alcohols were lower in the traditional rice‐adjunct beer than those in the extruded‐rice‐adjunct beer, but both levels satisfied the national standard for beer. Gas chromatography–mass spectrometry was employed to identify the flavour compounds of both beer samples through headspace–solid‐phase microextraction. Copyright © 2017 The Institute of Brewing & Distilling  相似文献   

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The volatile compounds of Cuban black mangrove (Avicennia germinans L.) honey were analysed by solid‐phase microextraction (SPME) followed by gas chromatography–mass spectrometry and gas chromatography–olfactometry. A total of 66 compounds were positively identified in this product for the first time. Application of the aroma extract dilution analysis in a novel approach, which consisted of carrying out successively dilutions of the honey sample with a synthetic honey before the SPME, revealed 17 odour‐active areas in the flavour dilution factor range of 32–1024. On the basis of the quantitative data and odour thresholds, odour activity values (OAV; ratio of concentration to odour threshold) were calculated. Sixteen compounds showed OAVs >1, among which dimethyl sulphide, 3‐methyl butanal, 2‐methylbutanal, heptanal, octanal, phenylacetaldehyde, (Z)‐linalool oxide, (E)‐linalool oxide, nonanal, hotrienol, isophorone, lilac aldehyde A, 1‐nonanol, decanal, 4‐vinyl‐2‐methoxyphenol and (E)‐β‐damascenone showed the highest values and should be considered as the most odour‐active compounds, particularly (E)‐β‐damascenone, nonanal and decanal.  相似文献   

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Changes in the volatile aroma compounds of pineapple (Ananas comosus) during freezing and thawing were compared against fresh samples to determine the effect of freezing on pineapple flavour. An HS‐SPME–GC–MS analysis showed that the Smooth Cayenne pineapple variety had nineteen volatile compounds, in four classes of compounds including fourteen esters, two hydrocarbons, two sulphur‐containing compounds and one lactone. The main characteristic volatile compounds of the fresh pineapple were methyl hexanoate, ethyl hexanoate, ethyl 3‐methylthiopropanoate and 1‐(E,Z)‐3,5‐undecatriene. Freeze–thaw cycles were associated with the loss of some volatile aroma compounds, particularly the esters which were found to be the main characteristic of fresh pineapples. The freezing and thawing process was found to cause damage to the pineapple tissues due to ice recrystallisation and dehydration which lead to the reduction of volatile aroma compounds.  相似文献   

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A methodology for quantification of β‐ionone in marine salt was developed using the headspace solid phase microextraction and gas chromatography–quadrupole mass spectrometry (HS–SPME/GC–qMS). Quantification of β‐ionone was achieved by linear regression from an analytical plot of pure standard using the target ion at m/z 177 by ion extraction chromatography (IEC). HS–SPME/GC–qMS combined with IEC mode allowed quantification of trace levels (ng/l) of β‐ionone in marine salt aqueous solutions. The methodology developed presented a good linearity (R2 = 0.981) for the range of concentrations used (16 a 568 ng/l) and a good reproducibility (15%), with limits of detection and quantification of 9 and 29 ng/l, respectively. This methodology was applied to marine salt from different geographical origins (Portugal, France, and Cape Verde). Estimated concentrations of β‐ionone in marine salt varied from 241 to 888 ng/kg of salt. The highest values were found for Aveiro, in Portugal, and Guérande, in France, in environments surrounded by a large number of plant and algae diversity. However, in Castro Marim and Tavira (in Algarve, South of Portugal), this compound was not found. According to the odour threshold of β‐ionone in water (30 ng/l), aqueous solutions with more than 100 g/l of marine salt can exhibit a violet odour. Similar conditions can occur in the ponds with higher levels of salinity of the traditional saltpans. This methodology proved to be a useful tool for screening and quantification of β‐ionone, a compound shown to present potential contribution to marine salt aroma. Copyright © 2010 John Wiley & Sons, Ltd.  相似文献   

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The impact of storage conditions on volatile flavour profile of field pea cultivars was evaluated. Seeds were kept at 4 °C, room temperature (approximately 22 °C) and 37 °C for 12 months. Headspace solid‐phase microextraction gas chromatography–mass spectrometry was used for extraction and identification of volatile flavour compounds (VFCs). Significant (P < 0.01) differences in the concentration of VFCs were observed during storage. All cultivars kept at 22 and 37 °C had higher mean value of aldehydes compared to those kept at 4 °C. Alcohols, hydrocarbons, ketones, terpenes and esters were higher in samples stored at 4 °C compared to those at higher temperatures. 1‐Hexanol, hexanal, styrene, 2‐butanone, dimethyl sulphide, 3‐carene, ethyl acetate and 2, 3‐diethyl‐5‐methyl pyrazine were the most abundant compounds found in peas. Results from this study could be useful in identifying improved conditions of storage to enhance flavour properties of peas.  相似文献   

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目的建立固相微萃取-气相色谱-串联质谱法快速筛查检测葡萄酒中农药残留。方法葡萄酒样品稀释后进行固相微萃取,直接进行气相色谱-串联质谱检测。优化选择了萃取纤维类型、萃取方式、萃取时间等固相微萃取的实验条件,考察了方法性能(检出限、添加回收率和精密度等)。结果确定方法可检测目标农药为94种,其检出限10μg/L,平均回收率在60%~110%之间,且方法的重复性和再现性标准偏差分别在20%和30%之内。结论该检测方法操作简便、快速,单个样品分析时间不超过1 h,适用于葡萄酒中农药残留的快速筛查检测。  相似文献   

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The aim of this research was to determine which compounds contribute to the flavour of agricultural distillates and to indicate those compounds which are responsible for a deterioration of sensory quality. Aroma profiling was carried out by headspace solid‐phase microextraction (HS‐SPME) and gas chromatography‐olfactometry (GC–O). Aroma profiles were obtained using the fingerspan method. It was ascertained that the aroma profiles of agricultural distillates contain about 40 odours, some of which may serve in discriminatory analysis as markers of sensory quality. Some of the aroma compounds could be identified with the use of a mass spectrometer. It was found that the greatest amount of information on quality was obtained through analysis of the most intense odours detected in all or almost all samples, and that two odours formed the most radical indicators of sensory quality, being the result of the presence of two compounds, dimethyl trisulphide and geosmin. Copyright © 2009 John Wiley & Sons, Ltd.  相似文献   

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Flavor volatiles are important components of alcoholic beverages. In this study, headspace solid‐phase microextraction and gas chromatography—mass spectrometry (HS‐SPME‐GC‐MS) were investigated for the determination of flavor‐contributing volatiles for apple wine. HS‐SPME parameters were defined, including fiber coatings, extraction time, and extraction temperature. Good linearity, recoveries, and repeatability of the SPME method using carboxen‐polydimethylsiloxane (carboxen‐PDMS) fiber were obtained with r2 values, recoveries, and relative standard deviations ranging from 0.9112 to 0.9960, 80.23% to 110.21%, and 1.5% to 6.4% respectively using standard solution. No significant effects of ethanol concentration on headspace concentrations of analytes were observed when ethanol concentration changed from 0% to 12% (v/v), indicating that the HS‐SPME‐GC‐MS method can be used for the determination of flavor volatiles in apple wine with an alcohol content below 12% (v/v) as well as in apple juice, and the method enables the monitoring of volatiles in mash during fermentation.  相似文献   

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BACKGROUND: The aim of this study was to evaluate the effect of the whole non‐volatile wine matrix composition on the volatility of typical wine aroma compounds by comparing the slopes of regression lines of five deodorised and reconstituted wines with the slopes calculated for the same compounds in a control wine with no matrix effect. RESULTS: The main effect observed was a reduction in the slopes, or a retention effect, that was largest for the reconstituted sparkling wine, which showed between 11 and 69% lower slopes than the control wine. In addition, an increase in the slopes, or a ‘salting‐out’ effect, in the most compositionally complex reconstituted aged‐red and sweet wines was also noticed for some volatiles with a very low boiling point or a low hydrophobic constant value. CONCLUSION: This study has shown that the non‐volatile composition of wines strongly affects the volatility of wine aroma compounds. In addition, the aroma chemical class, in particular its physicochemical properties (volatility and hydrophobicity), strongly influences this behaviour. On the basis of these results, many odour threshold values calculated in simple hydroalcoholic solutions and usually employed to evaluate the odour importance of specific volatile compounds may have been over‐ or underestimated. Copyright © 2011 Society of Chemical Industry  相似文献   

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Differentiation of nectar and honeydew honeys is difficult, not only because of the wide variability in composition and organoleptic properties among samples from the same source, but also because of the frequent existence of honeys resulting from a blend of nectar and honeydew. A mathematical expression to evaluate the relative presence of honeydew in a honey sample (HD) has been developed from relevant physicochemical properties of honey samples selected as highly representative of both honey types on the basis of their physico‐chemical and melissopalynological analysis. As honey aroma depends on its volatiles composition, GC‐MS analysis of the volatile fraction obtained by SPME has been carried out in order to evaluate its usefulness in honey source differentiation. Stepwise regression from multicomponent volatiles data was used for the estimation of HD and for determining which volatile compounds were related to the different honey sources. Copyright © 2004 Society of Chemical Industry  相似文献   

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Shochu, a traditional Japanese distilled liquor, makes use of rice koji, which is koji mould grown on rice grain. Rice koji is an essential ingredient of Japanese liquors such as shochu, and it plays a role as a source of the enzyme to degrade starch. However, there has been no research on the effect of rice koji on the flavour of shochu. Therefore, in this study, the volatile compounds in shochu derived from rice koji were investigated. Two shochu samples were prepared to assess the contribution of rice koji to the flavour. One shochu sample was prepared from rice koji, yeast and water (rice kojishochu). The other shochu sample was obtained from steamed rice and various enzymes instead of rice koji (enzyme‐shochu), along with yeast and water. The volatile compounds were analysed by gas chromatography–mass spectrometry (GC‐MS) and GC‐MS/olfactometry with aroma extract dilution analysis. The results showed that enzyme‐shochu had a higher flavour dilution value of dimethyl trisulphide and hexanal, whereas rice kojishochu had a higher flavour dilution value of some ester compounds that imparted aromatic odours such as fruity. Some unknown peaks representing compounds that impart characteristic odours such as soda, potato, lavender, and tea‐like were specifically detected in rice kojishochu. The concentrations and calculated odour active values of 14 compounds were measured. These results showed that isovaleraldehyde, ethyl caprylate, ethyl caproate and ethyl 2‐methylbutyrate played an important role in imparting the specific odour of rice kojishochu. Copyright © 2016 The Institute of Brewing & Distilling  相似文献   

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The variety of raw material plays a crucial role in the quality and authenticity of fruit juices and juice products. To characterise and classify apple juices according to variety on the basis of their volatile compounds, electronic nose (EN) and gas chromatography–mass spectrometry (GC‐MS) were applied to detect the apple juices prepared by eight different varieties. The EN was used to analyse the mixture of volatile compounds as a whole and enabled rapid classification of juice samples when coupled with linear discriminant analysis (LDA). LDA showed a perfect discrimination of apple juices based on varieties. GC‐MS was utilised to illustrate the differences of volatile compounds among juice samples. Identification of volatile compositions and their contents provides useful access to differentiate juices from different varieties.  相似文献   

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This study was conducted to determine the aroma‐active compounds of five sweet cherry cultivars grown in Yantai region, China, viz. ‘Lapins’, ‘Rainier’, ‘Stella’, ‘Hongdeng’ and ‘Zhifuhong’. The samples were extracted by headspace solid phase microextraction (HS–SPME) and analysed by gas chromatography–mass spectrometry (GC–MS) on DB‐wax and DB‐5 columns. A total of 52 volatiles were identified. Among these, hexanal, (E)‐2‐hexenal, 1‐hexanol, (E)‐2‐hexen‐1‐ol, benzaldehyde and benzyl alcohol were the main volatile compounds in the five cherries. Furthermore, the aroma compounds of five cherry samples were evaluated using a combination of HS–SPME and GC–olfactometry (GC–O) dilution analysis, and a total of 40 aroma‐active compounds were identified. The results suggested that hexanal, (E)‐2‐hexenal, (Z)‐3‐hexenal, nonanal, benzaldehyde and geranylacetone (FD ≥ 16), responsible for the green, orange, almond and floral characters of the cherries, were the potentially important common odorants in these cherry cultivars. Benzyl alcohol and linalool were significant aroma compounds in most cherries, with the exception of ‘Stella’ and ‘Rainier’. In addition, (E,Z)‐2,6‐nonadienal (cucumber‐like odour) could be important to ‘Hongdeng’ and ‘Zhifuhong’, and (E,E)‐2,4‐nonadienal (fatty odour) probably made great contributions to the aromas in ‘Lapins’ and ‘Stella’. From the present result, it was concluded that the aroma profiles were similar in the five cherry cultivars, but significant variation was found in the contributions of these compounds to each cherry. Copyright © 2010 John Wiley & Sons, Ltd.  相似文献   

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Photoinitiators (PIs) are widely used in food packaging materials, can migrate easily from packaging materials to food, and cause food contamination. It is essential to establish a method of determining PIs residues in food. A new method for simultaneously determining 10 kinds of PIs in milk has been established by using solid‐phase microextraction (SPME) combined with a simple method of protein precipitation as the pretreatment approach and gas chromatography/mass spectrometry as the detecting technique. The limits of detection for 10 PIs in different milks were between 0.05 and 1.4 μg/L (skimmed milk), between 0.07 and 2.2 μg/L (semi‐skimmed milk), between 0.11 and 4.4 μg/L (whole milk), respectively. The recoveries were from 71.5% to 133.5%, and the relative standard deviations were less than 15%. Twelve kinds of packed milk with different brands and fat contents were determined using this method.  相似文献   

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