品种和后成熟对NFC苹果浊汁挥发性香气成分的影响

为了探讨果实品种和后成熟度对苹果浊汁风味的影响,采用顶空-固相微萃取结合气相色谱-质谱联用技术,基于多元数据分析手段,非靶向分析了富士、嘎啦、华硕、金冠、澳洲青苹等5个品种,在3个后熟度下制成的NFC苹果浊汁挥发性香气成分差异。结果表明:醇类（2-甲基-1-丁醇、1-己醇等）、醛类（己醛、（E）-2-己烯醛等）和酯类（2-甲基乙酸丁酯等）为苹果浊汁的主要挥发性香气成分。品种和后熟度对苹果汁的特征性挥发性香气成分的含量和组成影响显著。澳洲青苹果汁挥发性香气成分总量少且含量低,醛类是其主要的挥发性香气物质;富士、嘎啦和金冠果汁则表现出相似的香气组分特征,酯类、醛类和醇类物质含量丰富,具有浓郁的香甜水果气味和青草味;华硕苹果汁的挥发性香气成分以醇类和醛类为主,整体具有清淡的香味和生青味。另外,随着不断后熟,不同品种苹果浊汁挥发性香气成分的变化呈现不同趋势。澳洲青苹和富士苹果汁中的香气成分逐渐累积,分别有15和28种挥发性化合物含量显著增加;嘎啦和金冠苹果汁香气物质含量呈现先上升后下降的趋势,在第二个后熟阶段风味最好;用采摘初期华硕苹果原料制成的苹果汁香气最浓郁,但随着不断后熟,挥发性香气含量显著降低。本研究开展的苹果汁风味特性研究,可为苹果浊汁加工的原料选择提供理论基础。     

苹果木烟熏液的品质特性

以苹果木烟熏液为研究对象,从感官品质、pH值、羰基化合物、酚类化合物、苯并（a）芘的含量、挥发性风味物质的组成和电子鼻分析等角度研究苹果木烟熏液的性质,并与目前市场上烟熏液产品进行比较。结果表明,苹果木烟熏液pH值为2.31,酚类化合物、羰基类化合物的含量分别达到9.94 mg/mL和7.91 g/100 mL,挥发性风味物质以酚类物质和醛类为主,相对含量分别为36.15%和17.58%,通过电子鼻主成分分析发现,苹果木烟熏液与其他几种烟熏液之间主成分有显著性差异,与市场其他烟熏液相比,在核心成分和特征性风味物质均有明显的优势,同时无苯并（a）芘检出,表明苹果木烟熏液具有良好的应用前景。     

不同烘丝模式对烟丝挥发性成分影响研究

  目的  研究薄板滚筒干燥（KLD）、气流干燥（HDT）两种烘丝模式对烟丝挥发性成分的影响规律。  方法  采用吹扫捕集-多模式进样口-气质联用(P & T-MMI-GC/MS)法鉴定烟丝挥发性成分。  结果  （1）主成分分析表明不同烘丝模式对烟丝挥发性成分的影响具有规律性差异。（2）相较烘前,KLD及HDT烘后烟丝中大部分挥发性成分含量降低,明显散失,挥发性成分的散失幅度都与其沸点相关,沸点越低,散失幅度越大;HDT加工烟丝中挥发性成分的散失幅度明显大于KLD。（3）不同类别挥发性成分散失幅度也有差异。脂肪酸降解产物、挥发性有机酸及酚类,烘后散失幅度相对较大;类胡萝卜素降解产物等散失幅度相对较小。      

Aroma volatiles recovered in the water phase of cashew apple (Anacardium occidentale L.) juice during concentration

BACKGROUND: There is a considerable loss of volatile compounds during the thermal concentration of cashew apple juice, damaging product quality, and as yet there is little research on the subject. Thus the purpose of this research was to identify the aroma volatiles evaporated off from cashew apple juice and recovered in the water phase during concentration of this beverage in an industrial plant. Water phase volatiles were extracted using dichloromethane, concentrated under a nitrogen flow, separated by gas chromatography (GC) and identified by GC‐mass spectrometry. In order to determine the contribution of each volatile to the cashew aroma, five trained judges evaluated the GC effluents using the Osme GC‐olfactometry technique. RESULTS: 71 volatiles were identified; of these, 47 were odour active. Alcohols were preferentially recovered in the cashew water phase, notably heptanol, trans ‐3‐hexen‐1‐ol and 3‐methyl‐1‐butanol, representing 42% of the total chromatogram area and imparting green grass and fruity aroma notes to the water phase. Esters represented 21% of the total chromatogram area, especially ethyl 2‐hydroxyhexanoate, ethyl trans ‐2‐butenoate and ethyl 2‐methylbutanoate, and were responsible for the fruity/cashew‐like aroma of the water phase. On the other hand, 3‐methylbutanoic and 2‐methylbutanoic acids were the volatiles that presented the greatest odour impact in the GC effluents of the water phase. CONCLUSION: Overall, the results of the present study strongly indicated that further concentration of the esters recovered in the water phase, either by partial distillation or by alternative technologies such as pervaporation, could generate a higher‐quality natural cashew apple essence. Copyright © 2011 Society of Chemical Industry     

Fungal infections of fresh-cut fruit can be detected by the gas chromatography-mass spectrometric identification of microbial volatile organic compounds

There is a large and rapidly growing market for fresh-cut fruit. Microbial volatile organic compounds indicate the presence of fungal or bacterial contamination in fruit. In order to determine whether microbial volatile organic compounds can be used to detect contamination before fruit becomes unmarketable, pieces of cantaloupe, apple, pineapple, and orange were inoculated with a variety of fungal species, incubated at 25 degrees C, then sealed in glass vials. The volatiles were extracted by headspace solid-phase microextraction and analyzed by gas chromatography-mass spectrometry. Forty-five compounds were identified that might serve as unique identifiers of fungal contamination. Fungal contamination can be detected as early as 24 h after inoculation.     

漂洗过程中草鱼鱼糜挥发性成分变化的研究

通过电子鼻技术和固相微萃取(SPME)结合GC-MS研究了漂洗过程中草鱼鱼糜挥发性成分的变化,通过电子鼻检测分析,能较好地判别出精滤后鱼糜与漂洗后鱼糜间、一次漂洗与两次或三次漂洗间鱼麋挥发性成分的差别,而二次漂洗与三次漂洗间鱼糜的挥发性成分差异无法明显判别;固相微萃取技术的使用中,萃取头有效地吸附了鱼糜中的挥发性成分,经NIST质谱数据库检索和文献对照,精滤后鱼糜、一次漂洗、两次漂洗、三次漂洗后鱼糜分别确定25、23、10和10种挥发性成分,均以挥发性羰基化合物和醇类为主,其相对百分含量分别为94.76%、93.03%、89.32%和92.03%.通过电子鼻和GC-MS实验结果可以推断漂洗对草鱼鱼糜的挥发性成分有显著的影响,但是两次和三次漂洗间无显著差异.     

Volatile profiles of aromatic and non-aromatic rice cultivars using SPME/GC–MS

Rice (Oryza sativa L.) is enjoyed by many people as a staple food because of its flavour and texture. Some cultivars, like scented rice, are preferred over others due to their distinctive aroma and flavour. The volatile profile of rice has been explored by other investigators, some of whom have also determined a corresponding aroma using GC/olfactometry. However, little research has been done to determine if different aromatic rice cultivars produce different flavour volatiles that would make them more desirable than others when cooked. In this study, seven aromatic and two non-aromatic cultivars were examined for their volatile profiles both before and after storage using solid phase microextraction (SPME) fibres in conjunction with gas chromatography/mass spectrometer (GC–MS). Ninety-three volatile compounds were identified, 64 of which had not been previously reported in rice. Differences were found in the volatile compounds of aromatic and non-aromatic rice besides 2-acetyl-1-pyrroline (2-AP). Most of the volatile compounds were present in freshly harvested rice and rice following storage, with very few new compounds being identified only after storage. Dellrose, an aromatic cultivar, and Cocodrie, a non-aromatic cultivar, had the most complex volatile profiles (over 64 volatiles). Sixteen compounds were found only in the aromatic cultivars, and some volatiles were found to be unique to specific aromatic cultivars. However, no distinctive pattern was observed that would identify a cultivar as being derived from Basmati, Khao Dawk Mali 105 (i.e. jasmine), or other sources of aroma. This study showed that there is a great diversity of volatiles in both aromatic and non-aromatic rice cultivars and, with further research, this may lead to a better understanding of the combination of compounds that gives a cultivar a unique flavour.     

SDE-GC-O-MS鉴定浓香葵花籽油香气活性物质

采用同时蒸馏萃取法（SDE）萃取浓香葵花籽油中的挥发性风味物质,利用气相色谱-质谱-嗅闻技术（GC- O-MS）对香气活性物质进行分离鉴定。SDE的最佳萃取条件为：二氯甲烷40 mL,加油量40 g,水添加量 200 mL,萃取时间3 h。经GC-MS分析共鉴定出96种挥发性风味物质,主要为醛类（29.29%）、杂环类（29.10%）、萜烯类（26.79%）、醇类（3.08%）、烯烃类（1.78%）、酮类（1.47%）、烷烃类（0.57%）、酯类（0.43%）和酸类（0.25%）。GC-O鉴定出24种香气活性物质,主要包括吡嗪类物质,赋予浓香葵花籽油烤香味;萜烯类物质,赋予其包括松针味的植物清香。     

Study on the volatile profile characteristics of oyster Crassostrea gigas during storage by a combination sampling method coupled with GC/MS

In this work, a combination sampling method, including headspace solid-phase microextraction (HSSPME) and steam distillation (SD), was used to study the oyster volatiles during storage followed by GC–MS detection. Twenty and twenty seven volatile compounds of fresh and deteriorated oysters were identified respectively by HSSPME, and 16 oyster volatiles were isolated by SD. HSSPME and SD were suitable for low-boiling-point and high-boiling-point volatiles, respectively. Therefore, the combination of HSSPME and SD could obtain more species of oyster volatiles during storage than any single method. Different volatile profile characteristics during oyster storage obtained by HSSPME were specified by principal component analysis. The top ten volatiles contributing most to the difference of oyster volatile profile characteristics during storage were distilled by common model analysis. The results tentatively suggested that the difference of entire volatile profile characteristics during oyster storage would provide more precise alarming information for oyster deterioration during storage than individual volatiles.     

Volatile constituents of unripe and ripe kundang fruits (Bouea macrophylla Griffith)

Kundang, a seasonal, tropical fruit is consumed either as raw (unripe) or ripe in south-east Asia. Investigations performed by using gas chromatography-mass spectrometry revealed volatile constituent compounds in ripe fruits to be much higher than unripe fruits. Nearly 82 compounds (comprising 99.96% of the total volatiles) and 121 compounds (encompassing 97.33% of the total volatiles) were identified in unripe and ripe fruits, respectively. Results generated is envisaged to enhance the existing database on tropical fruits volatile profiles, as well as benefit local food industries (to exploit the unique fragrance character impact compounds for aroma essence production) for commercial usage.     

Deodorization of Garlic Breath by Foods,and the Role of Polyphenol Oxidase and Phenolic Compounds

Garlic causes a strong garlic breath that may persist for almost a day. Therefore, it is important to study deodorization techniques for garlic breath. The volatiles responsible for garlic breath include diallyl disulfide, allyl mercaptan, allyl methyl disulfide, and allyl methyl sulfide. After eating garlic, water (control), raw, juiced or heated apple, raw or heated lettuce, raw or juiced mint leaves, or green tea were consumed immediately. The levels of the garlic volatiles on the breath were analyzed from 1 to 60 min by selected ion flow tube mass spectrometry (SIFT‐MS). Garlic was also blended with water (control), polyphenol oxidase (PPO), rosemarinic acid, quercetin or catechin, and the volatiles in the headspace analyzed from 3 to 40 min by SIFT‐MS. Raw apple, raw lettuce, and mint leaves significantly decreased all of the garlic breath volatiles in vivo. The proposed mechanism is enzymatic deodorization where volatiles react with phenolic compounds. Apple juice and mint juice also had a deodorizing effect on most of the garlic volatiles but were generally not as effective as the raw food, probably because the juice had enzymatic activity but the phenolic compounds had already polymerized. Both heated apple and heated lettuce produced a significant reduction of diallyl disulfide and allyl mercaptan. The presence of phenolic compounds that react with the volatile compounds even in the absence of enzymes is the most likely mechanism. Green tea had no deodorizing effect on the garlic volatile compounds. Rosmarinic acid, catechin, quercetin, and PPO significantly decreased all garlic breath volatiles in vitro. Rosmarinic acid was the most effective at deodorization.     

基于气相色谱-离子迁移谱法分析青霉侵染木耳菌丝的挥发性化合物

目的 基于气相色谱-离子迁移谱法(gas chromatography-ion mobility spectrometry, GC-IMS)研究青霉侵染木耳菌丝的挥发性化合物, 发掘潜在的特征标志物。方法 以分离自木耳菌包的桔青霉、歧皱青霉及黑木耳菌丝为研究对象, 采用气相色谱-离子迁移谱法(gas chromatography-ion mobility spectrometry, HS-GC-IMS)分析青霉侵染木耳菌丝不同时期挥发性化合物的种类及变化趋势, 并利用主成分分析(principal component analysis, PCA)比较不同侵染阶段挥发性化合物间的差异。结果 指纹图谱及PCA分析均可以比较明显地区分开青霉侵染木耳菌丝的不同阶段。挥发性化合物主要在桔青霉和歧皱青霉侵染木耳菌丝后的第4~8 d产生, 整体变化趋势基本一致, 共鉴定出41种化合物, 包括酯类、醇类、酮类、醛类及其他类。1-戊醇、乙酸己酯、2,3-戊二酮、2-丁酮、2,3丁二酮、1-丙醇、2-己醇、乙酸乙酯、丁酸乙酯、2-甲基丁酸等挥发性化合物可作为青霉侵染木耳菌丝的潜在标志物, 其中, 1-戊醇、乙酸己酯可作为青霉早期污染木耳菌丝的潜在标志物。3-羟基-2-丁酮可作为桔青霉侵染木耳菌丝后的潜在特征标志物。结论 本研究利用GC-IMS分析获得了两种青霉污染木耳菌丝的特征标志物, 为木耳栽培过程中青霉污染的早期预测提供了一定的理论基础。     

刺梨汁中挥发性成分测定及其呈香贡献分析

为全面剖析刺梨中挥发性成分的组成及其呈香贡献,采取顶空固相微萃取(headspace-solid phase microextraction,HS-SPME)和溶剂辅助风味蒸发(solvent-assisted flavor evaporation,SAFE)结合GC-MS对刺梨汁挥发性成分进行分析,通过香气活度值(odor activity value,OAV)评估挥发性成分对刺梨汁整体香气的贡献度。结果表明,HS-SPME和SAFE方法在刺梨汁中分别检测到67种和86种化合物,共鉴定出119种挥发性化合物,其中包括酯类49种,醇类28种,酸类9种,醛酮类16种,萜烯类6种,芳香族化合物9种和其他类2种。2种方法对挥发性化合物的提取效率不同,HS-SPME对低沸点强挥发性的化合物提取更为有效,SAFE提取到更多高沸点较难挥发的化合物,两者互补分析获得了较全面的分析结果,鉴定出了刺梨汁中更多种类的挥发性化合物。OAV分析表明,38种挥发性化合物对刺梨的香气有主要贡献作用,主要为酯类、醇类和醛酮类化合物,其中有16种挥发性成分首次被鉴定为刺梨汁中的香气活性成分。该研究可为贮藏和刺梨加工过程中的香气品质控制以及风味评价提供科学依据。     

Effects of the volatile organic compounds produced by Enterococcus spp. strains isolated from maize grain silos on Fusarium verticillioides growth and fumonisin B1 production

Fusarium verticillioides is a phytopathogenic fungus that can contaminate maize grain silos and result in important losses in the post-harvest product. The objective of this work was to investigate the effects of volatile organic compounds produced by four lactic acid bacterial strains isolated from maize grain silos on F. verticillioides M3125 growth and fumonisin B₁ (FB₁) production. The bacterial isolates 55 and 49 were identified as Enterococcus faecium and M4A and M4G as Enterococcus casseliflavus. The fungal growth was inhibited by 33.33% by the volatiles released by the M4A strain and by approximately 10% by the volatiles emitted by the 55 and 49 strains. The volatiles produced by the M4A strain also significantly reduced (88.75%) FB₁ biosynthesis. The gas chromatography–mass spectrometer analysis identified 21 volatile organic compounds, with diacetyl, acetic acid and acetoin being the main volatiles emitted by the four bacterial strains. Acetoin was the volatile produced in the highest proportion by the four strains, with M4A generating the highest proportion of diacetyl (35.11%). Diacetyl and acetic acid completely inhibited fungal growth at concentrations of 0.3 and 1 mM, respectively, while acetoin promoted fungal growth. Only acetoin significantly reduced FB₁ production. These results showed that diacetyl was the main compound involved in fungal inhibition, while the effect on FB₁ production could have been due to the combination of the volatile organic compounds produced by the M4A strain. In conclusion, the volatiles emitted by the E. casseliflavus M4A strain could be a promising tool for the biocontrol of F. verticillioides in storage maize grain silos.     

Feature Selection and Recognition from Nonspecific Volatile Profiles for Discrimination of Apple Juices According to Variety and Geographical Origin

Abstract: Apple juice is a complex mixture of volatile and nonvolatile components. To develop discrimination models on the basis of the volatile composition for an efficient classification of apple juices according to apple variety and geographical origin, chromatography volatile profiles of 50 apple juice samples belonging to 6 varieties and from 5 counties of Shaanxi (China) were obtained by headspace solid‐phase microextraction coupled with gas chromatography. The volatile profiles were processed as continuous and nonspecific signals through multivariate analysis techniques. Different preprocessing methods were applied to raw chromatographic data. The blind chemometric analysis of the preprocessed chromatographic profiles was carried out. Stepwise linear discriminant analysis (SLDA) revealed satisfactory discriminations of apple juices according to variety and geographical origin, provided respectively 100% and 89.8% success rate in terms of prediction ability. Finally, the discriminant volatile compounds selected by SLDA were identified by gas chromatography‐mass spectrometry. The proposed strategy was able to verify the variety and geographical origin of apple juices involving only a reduced number of discriminate retention times selected by the stepwise procedure. This result encourages the similar procedures to be considered in quality control of apple juices. Practical Application: This work presented a method for an efficient discrimination of apple juices according to apple variety and geographical origin using HS‐SPME‐GC‐MS together with chemometric tools. Discrimination models developed could help to achieve greater control over the quality of the juice and to detect possible adulteration of the product.     

Characterisation of calamansi (Citrus microcarpa). Part II: Volatiles,physicochemical properties and non-volatiles in the juice

Calamansi juices from three countries (Malaysia, the Philippines and Vietnam) were characterised through measuring volatiles, physicochemical properties and non-volatiles (sugars, organic acids and phenolic acids). The volatile components of manually squeezed calamansi juices were extracted using dichloromethane and headspace solid-phase microextraction, and then analysed using gas chromatography–mass spectrometry/flame ionisation detector, respectively. A total of 60 volatile compounds were identified. The results indicated that the Vietnam calamansi juice contained the highest amount of volatiles. Two principal components obtained from principal component analysis (PCA) represented 89.65% of the cumulative total variations of the volatiles. Among the non-volatile components, these three calamansi juices could be, to some extent, differentiated according to fructose and glucose concentrations. Hence, this study of calamansi juices could lead to a better understanding of calamansi fruits.     

同时蒸馏萃取法提取花生油挥发性物质的研究

采用同时蒸馏萃取法结合气相色谱-质谱分析技术（SDE-GC-MS）,对水酶法制备的花生油挥发性物质进行提取和分析,优化同时蒸馏萃取条件。结果表明：花生油总挥发性化合物种类及吡嗪类化合物相对含量均随样品量的增加而增加;二氯甲烷作为萃取溶剂萃取得到的总挥发性化合物种类及吡嗪类化合物相对含量较乙醚多;在花生油用量为30 g时,采用二氯甲烷可以萃取出66种化合物,经质谱分析可鉴定出42种化合物,其中吡嗪类化合物有6种,占总挥发性成分6.73%。     

Dp368 糖苷酶酶解对“赛美蓉”葡萄汁挥发性风味物质的影响

以“赛美蓉”葡萄汁为原料,研究Dp368糖苷酶酶解对其挥发性风味物质的影响。采用顶空固相微萃取结合色谱技术和气相色谱-质谱联用技术进行分析。结果显示：酶解“赛美蓉”澄清葡萄汁中初步分离定性物质有64种,多为C10以下的组分,醇类物质最多;Dp368酶解汁与对照相比,挥发性风味物质总释放量有所增加,但不明显,仅增加了3.12%。Dp368酶解可明显促进酸类、萜烯类、部分苯衍生物及C5～C7挥发性化合物的释放。     

Comparative analyses of apple aroma by a tin-oxide gas sensor array device and GC/MS

The apple cultivars “fuji”, “jina” and “huaniu” aroma volatiles were collected and analyzed using a tin-oxide gas sensor array device and the gas chromatography combined with mass spectrometry (GC-MS). Twenty two of the most abundant volatile compounds were taken into account for further study. Eight compounds were found in every cultivar. The principal components analysis (PCA), partial least squares (PLS) and back-propagation feed-forward artificial neural network (BP-ANN) were used to analyze the sensor array and SPME-GC-MS measurements. From the plots of the first two PCs by PCA, different apple cultivars could be clearly distinguished by SPME-GC-MS measurements, while there was slight overlap by sensor array measurements. BP-ANN was used to distinguish different cultivars based on gas sensor array responses, and the accuracy was 87%. Due to the composition of gas sensors in the array, results of PLS models showed that the correlation between fourteen gas sensor array responses and the two PCs of twenty-two compounds were better than the correlation between those and each volatile compound. Furthermore, an ANN was used to build the relationship between the two predicted PCs by PLS model and the three cultivars. The recognition probability was increased to 97%.