电子鼻技术对不同贮藏条件银杏果挥发性组分的比较

为了分析不同的贮藏条件银杏果中挥发性组分的性质,采用电子鼻对不同材料包装和不同保鲜剂处理后的银杏果挥发性气味进行检测,并对所得数据进行分析。采用不同材料包装的银杏果,传感器主成分1和主成分2的累积方差贡献率为99.44%,鉴别指数达到94;采用不同保鲜剂处理的银杏果,传感器主成分1和主成分2的累积方差贡献率为99.48%,鉴别指数达到86。结果表明：采用不同包装材料和不同保鲜剂处理的银杏果在贮藏一段时间后气味均有较大差异,运用电子鼻能够很好地将其区分。电子鼻对经过不同材料包装贮藏和不同保鲜剂处理贮藏的银杏果挥发性气味反应灵敏,可以用于银杏果气味分析。     

Molecular Mass and Solubility Changes in Pectins during Storage of Satsuma Mandarin Fruits (Citrus unshiu Marc.)

Soluble pectins in satsuma mandarin fruits stored at 5°C were investigated by High Performance Gel Filtration chromatography. Pectins isolated from the flavedo, albedo, membranes and juice sacs were separated into four fractions. The hydrochloric acid soluble pectin fraction in each part was the highest and decreased slightly while the water-soluble pectin increased slightly. The avergae molecular weights of the fractionated soluble pectins in juice sacs were nearly constant but those in flavedo, albedo and membranes decreased as storage time increased. The ratios of higher molecular weight of water soluble and ammonium oxalate-soluble pectins in all the four parts and those of hydrochloric acid soluble pectin in flavedo and membranes decreased as ratios of lower molecular weight fractions increased.     

不同地域蜂胶的挥发性成分分析

采用顶空固相微萃取-气质联用技术分析5个省(安徽、吉林、河北、河南、甘肃)37个蜂胶样品的挥发性成分。结果共测出49种化合物,包括醇、酯、醛以及萜烯类化合物;对37个蜂胶样品的挥发性组分的相对含量进行主成分分析,结果通过这种方法能够对不同地域的蜂胶进行一定的区分,其中甘肃省的蜂胶样品与其他4省的差别最大,而河南、河北和安徽3省的蜂胶样品未能区分开。     

果蔬可食性涂膜剂结构组分与功能的研究进展

随着人们绿色消费和环保意识的增强,可食性涂膜剂成了国内外学者研究的热点,其添加剂成分也向天然、可食的方向发展。文中综述了果蔬可食性涂膜剂结构组分与功能的研究进展,包括多糖类膜、蛋白质膜和脂质膜,以及添加于可食性涂膜剂中的抗氧化剂、杀菌剂和其他助剂的研究情况。     

Sensory Attributes and Volatile Components of Stored Strawberry Juice

Juices from three strawberry cultivars were stored at 2°C and 25°C for 6 wk and evaluated for the sensory attributes fresh strawberry, strawberry-jam, off-flavor, green, and sweet. Fresh flavor declined while off-flavor increased during storage, with the largest changes occurring at 25°C. Juice color and ascorbic acid also degraded much faster at 25°C. Fifteen volatiles were measured using headspace solid phase microextraction and gas chromatography. 2,5-dimethyl-4-hydroxy-3(2H)-furanone and 2,5-dimethyl-4-methoxy-3(2H)-furanone were positively related to fresh flavor and negatively related to off-flavor, while -terpineol was inversely related to fresh flavor. These volatiles explained almost 90% of the variation for fresh and off-flavor attributes.     

Volatile Components in Salt-Fermented Fish and Shrimp Pastes

Volatile compounds in salt-fermented anchovy, big-eyed herring, hair tail viscera, and shrimp pastes were compared by simultaneous steam distillation-solvent extraction/gas chromatography/mass spectrometry (SDE/GC/MS). A total of 155 volatile compounds were detected. Of these, 111 were positively identified consisting mainly of aldehydes, ketones, alcohols, esters, aromatics, nitrogen-, and sulfur-containing compounds. Lipid-derived components, such as aldehydes, alcohols, and esters, comprised the majority of volatile compounds from fish pastes, while heterocyclic nitrogen-containing compounds, such as pyrazines, were predominant in shrimp paste.     

添加不同水果的柑橘果酒酿造与品质分析

为解决柑橘果酒营养功能单一、香气滋味结构欠佳等不足,实验研究了柑橘分别与不同用量苹果、雪梨、猕猴桃果醪混合发酵对酒体品质的影响,考察了黄酮、多酚、V_C和总氨基酸含量等营养成分差异。结果显示,苹果等其它水果的添加对发酵过程总糖降低有一定延缓效应,但对果酒总酸含量有促进作用。与单一柑橘果酒相比,黄酮含量随着苹果用量的增加而显著增加(p<0.05),在苹果最大用量(1:1)酒样中,黄酮含量达到393.43 mg/L。在添加猕猴桃的果酒中V_C含量增加显著(p<0.05),等量柑橘和猕猴桃混酿果酒中V_C含量最高,是柑橘果酒的4.38倍。此外,苹果和猕猴桃的添加对果酒中总氨基酸含量也有一定的促进作用,其中柑橘和苹果1:1用量果酒中总氨基酸含量最高,达到604.11 mg/L,比柑橘果酒高出了9.11%。感官分析结果显示,柑橘猕猴桃2:1的酒样感官品评分值最高,达到81.73分,最低的为单一柑橘果酒(76.73分)。综合各项指标的主成分分析(PCA)结果进一步验证了添加苹果等其它水果对柑橘混酿果酒品质改善和提升方面的显著效果。     

比较不同贮藏年份宁红金毫中香气组分的变化

为了解宁红金毫红茶在贮藏过程中其香气组分发生变化情况,该研究利用顶空固相微萃取（Headspace Solid-Phase Microextraction,HS-SPME）结合气相色谱质谱（Gas Chromatograph-Mass Spectrometer,GC/MS）联用分析技术,对贮藏0、1、2、3年的宁红金毫香气组分进行分析。结果表明,从不同贮藏年份宁红金毫中共鉴别出81种香气组分,不同贮藏年份的宁红金毫香气组分有显著差异,主成分分析（Principal Component Analysis,PCA）、偏最小二乘法-判别分析（Partial Least Squares-Discriminant Analysis,PLS-DA）香气组分相对含量,可以有效区分不同贮藏年份的宁红金毫。不同贮藏年份宁红金毫中主要由14种关键香气组分变化引起的,分别是：香叶醇、水杨酸甲酯、苯甲醇、苯乙醛、苯乙醇、芳樟醇、2,4,6-三叔丁基苯酚、反式氧化芳樟醇（呋喃类）、苯甲醛、雪松烯、顺式氧化芳樟醇（吡喃类）、乙酸香叶酯、2-已烯醛、香叶酸甲酯。随着贮藏时间的增加：苯乙醇、雪松烯、反式氧化芳樟醇（...     

不同贮藏期冷却滩羊肉煮制后挥发性气味物质的变化

为研究不同贮藏期冷却滩羊肉煮制后挥发性气味物质的变化,采用固相微萃取-气相色谱-质谱结合电子鼻技术对0～4℃不同贮藏期(0、2、4、6、8、10 d)冷却滩羊肉煮制后产生的挥发性气味物质进行测定,并从宏观角度对挥发性气味物质的气味强度进行分析.最终共检测到38种挥发性气味物质,包括醛类19种、醇类11种、酮类4种、酸类...     

SPME-GC-MS结合电子鼻技术分析不同品种猕猴桃酒香气物质

采用固相微萃取-气相色谱-质谱（gas chromatography-mass spectrometry,GC-MS）联用和电子鼻技术对徐香、海沃德和黄金果猕猴桃酿造的3 种猕猴桃酒中香气物质进行测定和分析。结果表明：3 种猕猴桃酒中共检出63 种挥发性香气物质,其中最主要的为醇类、酯类、酸类及萜烯类。徐香酒、海沃德酒和黄金果酒中分别检出52、45 种和46 种香气物质,总质量浓度分别为81.56、43.92 mg/L和15.07 mg/L,且3 种酒共有特征香气物质包括丁酸甲酯、乙酸异戊酯、正己酸乙酯、丁香酚、辛酸、桉叶油醇和对乙烯基愈创木酚。此外,电子鼻与GC-MS测定结果基本一致,均表明不同猕猴桃酒间香气特性有较大差异,其中徐香酒与海沃德酒风味差异最显著;且利用主成分分析法可完全将3 种酒区分。     

江永香柚柚皮中挥发性化学成分的GC-MS联用分析研究

采用水蒸气蒸馏法分别提取江永香柚外黄皮和内白皮中的挥发性成分,经GC-MS联用分析,分别鉴定出61种和22种化合物.江永香柚外黄皮中挥发性成分以柠烯碳氢化合物为主体成分,其中柠檬烯含量占粗精油的76.04%,江永香柚内白皮则以十八碳二烯酸、棕榈酸和七聚氧化乙烯为主体成分.     

Vinification Effects on Changes in Volatile Compounds of Wine

Alcohols, esters and fatty acids in wines from red, rose and carbonic maceration of Monastrell grapes were measured during yeast fermentation. Isolated volatile compounds were analyzed by gas chromatography alone and with-mass spectrometry. Increases in these compounds was most important during the first days of fermentation and concentrations varied between vinifications. The lower fermentation temperature and shorter skin contact time of rose vinification produced higher concentrations of esters and acids than in red wine. The intracellular fermentation in carbonic maceration vinification resulted in formation of almost all esters and fatty acids before alcoholic fermentation started. The final wine was closer to rose than red wine in aromatic composition.     

海红果香气成分的气相色谱-质谱分析

采用同时蒸馏萃取法提取海红果中的挥发性成分,利用气相色谱-质谱联用仪进行分析。分离并确定了60种成分,占总质量的97%。并用面积归一化法测定了各种成分的质量分数,其中醇类化合物17种、醛类化合物17种、酯类化合物4种、酮类化合物5种、烯烃类化合物4种、烷烃类化合物6种。     

Volatile Sulfur Compounds Formed in Disrupted Tissues of Different Cabbage Cultivars

Thirty-eight cultivars of cabbage (Brassica oleracea var capitata) were analyzed for production of volatile sulfur compounds after samples were homogenized and held at 30 °C from 10 to 100 min. Allyl iso-thiocyanate was detected in most cultivars, and it was formed rapidly compared to methanethiol-related compounds. Patterns of methane-thiol production varied among cultivars. Hydrogen sulfide formed rapidly compared to methanethiol-related compounds, but it was completely depleted after 40 min. Dimethyl disulfide and dimethyl trisulfide concentrations initally low (< 0.78 ppm), increased linearly through 100 min (to 3.3 ppm). Wide variations in abilities to produce volatile sulfur compounds were observed for the different cultivars.     

电子鼻结合GC-MS分析不同处理蓝莓货架期间果实的挥发性成分

采用顶空固相微萃取-气相色谱-质谱(head space solid-phase microextraction and gas chromatography mass spectrometry,HS-SPME-GC-MS)联用并结合电子鼻技术检测蓝莓冰温贮藏((-0.5±0.3)℃)30 d后4℃货架期的挥发性成分,研究1-甲基环丙烯(1-methylcyclopropene,1-MCP)结合气调保鲜(MAP)处理对蓝莓贮后货架期间挥发性成分变化的影响。结果表明:在蓝莓货架期过程中醛类(24.86%~91.98%)、醇类(0.24%~23.85%)、萜类(2.00%~43.00%)是最主要挥发性成分,特征挥发性成分为2-己烯醛(青草香气)、芳樟醇(浓青带甜的木青气息)、香叶醇(温和、甜的玫瑰花气息)。对蓝莓挥发性成分的分析使用判别分析法优于主成分分析法,可以看出3 d是货架期蓝莓主要挥发性成分的变化拐点,且贡献率最高的传感器为W5S。MAP+1-MCP联合处理可延缓货架期间醛类成分流失,对于醛类流失抑制效果顺序为MAP+1-MCP>1-MCP>MAP>CK。     

Volatile Components in Blue Crab (Callinectes sapidus) Meat and Processing By-Product

Volatile components in fresh-picked blue crabmeat and processing byproduct were compared by simultaneous steam distillation-solvent extraction/gas chromatography/mass spectrometry (SDE/GC/MS). Compounds were identified in crabmeat (771 and by-product (80) of which 58 were common to both. Some compounds 154) were identified for the first time in crab. Trimethylamine, four alkanes (C15–C17, C19), and indole were highest (> 50 ng/g)) in crabmeat, while trimethylamine, carbon disulfide, dimethyltrisulfide, two alkanes (C15 and C17), geranylacetone, and 1–dodecanol were highest in by-product. Of compounds from both samples, 23 were higher in by-product and 7 were higher in the meat. Crab processing by-product may be a good source for volatile flavor recovery.     

玉米储藏过程中挥发性成分变化研究

为了研究玉米储藏期间气味变化情况,采用优化的顶空固相微萃取-气质联用法(HS-SPME-GC-MS)分析玉米在常温(25℃)密闭储藏过程中的主要挥发性成分组成。检出的物质主要包括烃类、醛类、酯类、醇类、酮类、酸类和少量杂类物质。结果表明,在储藏过程中烃类物质总相对含量在储藏末期比储藏初期有所增加。酸类物质相对含量呈缓慢上升但含量较低。酮类物质相对含量较低且呈逐渐降低趋势。醇类挥发性成分在储藏120 d前呈现增加趋势,在120 d后有所降低。醛类和酯类物质相对含量呈现先升高后降低,二者相对含量较高,储藏180 d后的相对含量接近于0 d,是玉米风味的主要贡献物质。而烃类和醇类风味阈值较高,不是玉米储藏期间风味的主要贡献物质。25℃下密闭储藏180 d后的玉米其气味与储藏0 d的玉米相比,并未发生人嗅觉可感知的明显异味变化。     

Identification and Quantification of Volatile Chemical Spoilage Indexes Associated with Bacterial Growth Dynamics in Aerobically Stored Chicken

Volatile organic compounds (VOCs) as chemical spoilage indexes (CSIs) of raw chicken breast stored aerobically at 4, 10, and 21 °C were identified and quantified using solid phase microextraction (SPME) combined with gas chromatography‐mass spectrometry (GC‐MS). The growth dynamics of total viable count (TVC), psychrotrophs, Pseudomonas spp., lactic acid bacteria (LAB), Brochothrix thermosphacta and H₂S producing bacteria were characterized based on maximum growth rates (μ_max), maximal microbial concentration (N_max) and at the moment of microbial shelf life (S_values), calculated from Gompertz‐fitted growth curves. Pseudomonas spp. was predominant species, while B. thermosphacta was characterized by the highest μ_max. The microbiological and sensory shelf lives were estimated based on TVC, Pseudomonas spp., and B. thermosphacta counts and sensory evaluation, respectively. Among 27 VOCs identified by GC‐MS in spoiled chicken samples, ethanol (EtOH), 1‐butanol‐3‐methyl (1But‐3M), and acetic acid (C₂) achieved the highest Pearson's correlation coefficients of 0.66, 0.61, and 0.59, respectively, with TVC, regardless of storage temperature. Partial least squares (PLS) regression revealed that the synthesis of 1But‐3M and C₂ was most likely induced by the metabolic activity of B. thermosphacta and LAB, while EtOH was attributed to Pseudomonas spp. The increase in concentration of selected volatile spoilage markers (EtOH, 1But‐3M, and C₂) in the headspace over spoiled chicken breast was found to be statistically significant (P < 0.05) with TVC growth. These findings highlight the possibility of analyzing the combination of 3 selected spoilage markers: EtOH, 1But‐3M, and C₂ as rapid evaluation for poultry quality testing using SPME‐GC‐MS.     

不同产地花生酱的挥发性风味成分比较分析

为研究不同提取方法比较不同产地花生酱中挥发性风味物质的差异。采用顶空固相微萃取（HS-SPME）和同时蒸馏萃取（SDE）两种方法提取4种不同国家花生酱,中国莺歌花生酱（Z）、美国四季宝花生酱（M）、澳大利亚贝科姆花生酱（A）、新西兰皮卡思花生酱（X）的挥发性风味物质,用气相色谱-质谱联用技术（GC-MS）对挥发性物质进行鉴定以内标法计算各类物质的含量,并结合气味活度值（OAV）方法分析不同风味物质对整体风味的贡献程度。结果表明：4种花生酱共鉴定出挥发性物质202种,其中SDE鉴定出70种,HS-SPME鉴定出142种。A、M、X、Z样品分别鉴定出71种、93种、58种和141种挥发性物质。HS-SPME鉴定挥发性成分更全面,而SDE法可较灵敏的检测吡嗪类和醛类成分。Z样品中含有最丰富的风味物质其中醛类风味物质含量最高为14 901.17μg/kg。结合OAV分析得到：对四种花生酱的整体风味贡献程度较大的风味物质均为己醛、苯乙醛、苯乙醇、2,5-二甲基吡嗪、2-乙基-3,6-二甲基吡嗪、2-乙基-5-甲基吡嗪。Z样品的风味成分最丰富,风味品质要好于其他三种花生酱,其烤花生香味、杏味较突出...     

Advances in Edible Coatings for Fresh Fruits and Vegetables: A Review

Edible coatings are an environmentally friendly technology that is applied on many products to control moisture transfer, gas exchange or oxidation processes. Edible coatings can provide an additional protective coating to produce and can also give the same effect as modified atmosphere storage in modifying internal gas composition. One major advantage of using edible films and coatings is that several active ingredients can be incorporated into the polymer matrix and consumed with the food, thus enhancing safety or even nutritional and sensory attributes. But, in some cases, edible coatings were not successful. The success of edible coatings for fresh products totally depends on the control of internal gas composition. Quality criteria for fruits and vegetables coated with edible films must be determined carefully and the quality parameters must be monitored throughout the storage period. Color change, firmness loss, ethanol fermentation, decay ratio and weight loss of edible film coated fruits need to be monitored. This review discusses the use of different edible coatings (polysaccharides, proteins, lipids and composite) as carriers of functional ingredients on fresh fruits and vegetables to maximize their quality and shelf life. This also includes the recent advances in the incorporation of antimicrobials, texture enhancers and nutraceuticals to improve quality and functionality of fresh-cut fruits. Sensory implications, regulatory status and future trends are also reviewed.