Analysis of Volatile Compounds from Strawberry Fruit Stored under Modified Atmosphere Packaging (MAP)

Volatile compounds were extracted from strawberries stored at 1°C for 10 days under modified atmosphere packaging (MAP) conditions in high barrier pouches flushed with either carbon dioxide, mixed gas, or air, and identified by gas chromatography/mass spectrometry. Canonical variate analysis based on 25 selected volatile compounds classified the samples according to treatment and/or quality level. Unpackaged samples, MAP samples treated with air or mixed gas kept in storage for 3 days, and strawberries evaluated at day 0 were all initially different from strawberries held in carbon dioxide. After 10 days storage, all MAP strawberries were classified close together and quality attribute scores were lower.     

基于HS-SPME-GC-MS和OAV分析黄山地区不同茶树品种红茶香气的差异

为探究黄山地区不同茶树品种红茶的香气差异,选取在黄山地区广泛种植的9 个茶树品种鲜叶,以祁门红茶的加工工艺制成红茶,其中有性系茶树品种‘祁门槠叶种’为加工祁门红茶的当家品种,其余8 个均为无性系良种,分别是‘翠绿1号’、‘凫早2号’、‘皖茶4号’、‘舒茶早’、‘皖茶91’、‘中茶108’、‘浙农117’和‘浙农139’。感官审评结果显示,9 个品种红茶香气类型均为甜香型,其中‘祁门槠叶种’红茶具有典型的“祁门香”,花香明显;‘皖茶4号’红茶香气甜香为主,稍带花香,其余品种红茶甜香明显,而花香显著低于‘祁门槠叶种’和‘皖茶4号’红茶。气顶空固相微萃取-气相色谱-质谱分析结果显示,共有46 个高峰度化合物被鉴定,利用阈值共计算出21 个气味活度值大于1的挥发性成分;主成分分析表明‘祁门槠叶种’红茶、‘皖茶4号’红茶香气显著有别于其他品种红茶;正交偏最小二乘判别分析表明(E)-β-紫罗酮、芳樟醇、β-月桂烯、香叶醇、己醛、壬醛和庚醛7 个化合物在组间的变量投影重要性值大于1,可能是影响‘祁门槠叶种’红茶香气显著有别于其他品种红茶的主要因素。本研究结果对了解不同品种红茶香气差异化合物及“祁门香”具有重要指导意义。     

不同成熟阶段柠檬果皮挥发物和酚类成分分析

为探究柠檬果皮香气和酚类成分在不同成熟阶段的变化特点,以抗病品种香水柠檬和泰吹柠檬不同成熟阶段果皮为材料,采用顶空固相微萃取结合气相色谱-质谱法分析其挥发物成分,高效液相色谱法测定其酚类成分。结果表明：2 个品种柠檬果皮中共检测到86 种挥发性成分,以萜烯类、醛类和醇类为主,香水柠檬果皮中倍半萜和醛类含量较高,泰吹柠檬果皮中单萜和醇类含量较高。香水柠檬果皮中单萜、倍半萜、醛类的含量在成熟期间发生显著变化,其中单萜、倍半萜含量均呈先下降后上升再下降的趋势,醛类含量呈上升趋势;泰吹柠檬果皮中单萜、醇类和醛类的含量在成熟期间发生显著变化,3 类香气物质的含量均呈先下降后上升的趋势。根据香气成分的香气值,香水柠檬和泰吹柠檬果皮中分别鉴定出26 种和22 种特征香气成分。在整个发育期中,对香水柠檬香气贡献最大的特征香气成分为癸醛、十二醛、香叶醛、芳樟醇和橙花醛,对泰吹柠檬香气贡献最大的特征香气成分为癸醛、芳樟醇、香茅醛、β-月桂烯和乙酸香茅酯。香水柠檬和泰吹柠檬果皮中分别检出12 种和15 种酚类物质,2 个品种柠檬果皮中酚酸总量无显著差异,泰吹柠檬果皮中类黄酮总量显著高于香水柠檬,其中泰吹柠檬果皮中多甲氧基黄酮总量为香水柠檬的20.94～118.75 倍。果实成熟对香水柠檬和泰吹柠檬果皮中酚酸总量和类黄酮总量有显著影响,随成熟度提高,2 个品种酚酸总量和类黄酮总量均呈下降趋势。研究结果为柠檬果实资源的利用和抗病种质创新提供支撑。     

Production of volatile compounds by Muskmelon,Cucumis melo

The volatile constituents of ‘PMR 45’, ‘Top Mark’, ‘Honeydew’ and ‘Crenshaw’ cultivars of Muskmelon were examined by trapping the essence on Porapak Q and analysing the eluted compounds on wall coated open-tubular glass capillary columns. The relative concentrations of forty-three compounds were determined. Also, by direct sampling of gas from the fruit cavity of ‘PMR 45’ and ‘Top Mark’ cantaloupe cultivars, the relative concentrations of fifteen compounds were measured daily over a period of eight days. Computer-constructed arrays of chromatograms revealed trends in the progressive changes of volatile compounds produced by the ripening fruits. The volatile constituents measured in this study could be fitted into groups, depending on the pattern exhibited by the production of that compound. One group showed a continuously accelerating rate of production (e.g. ethyl esters, acetaldehyde, ethanol) and another increased rapidly and then plateaued (e.g. acetate esters).     

CULTIVAR AND HARVEST DATE EFFECTS ON FLAVOR AND OTHER QUALITY ATTRIBUTES OF CALIFORNIA STRAWBERRIES

“Aromas,”“Diamante” and “Selva” strawberries were harvested in early and mid‐season and evaluated for quality attributes, flavor components, fermentative metabolites and physiological characteristics. Preference and flavor tests by consumer panels were also conducted. Cultivar variation was greater than harvest date variation as were differences in color, concentrations of anthocyanins, firmness, total soluble solids, sugars, pH, titratable acidity (TA), organic acids and aroma compounds. “Diamante” and “Selva” had higher aroma quality than “Aromas” fruits. The levels of fermentative metabolites were too low to have an impact on the aroma quality. “Diamante” and “Selva” strawberries had better overall flavor quality and were more preferred by consumers than “Aromas.” These differences were consistent over two harvest dates.     

梅花果实品质及抑菌、抗氧化活性分析

为揭示不同品种梅花果实的品质及抑菌、抗氧化活性差异,从抗寒梅花中筛选果实品质优良的品种,为抗寒花果兼用梅的选育以及梅花果实综合利用提供依据。对8个品种梅花果实的品质(外观品质和食用品质)性状、抑菌和抗氧化活性进行评价,利用高效液相色谱-质谱联用技术对酚类化合物进行分离和检测,对果实品质性状与抑菌和抗氧化活性进行相关性分析。结果表明:不同品种梅花果实的品质性状差异显著,‘淡丰后’、‘粉靥丰后’、‘武藏野’和‘飞绿萼’等级评价较高;‘丰后’、‘武藏野’、‘飞绿萼’总酚和总黄酮含量较高,从3个品种中都分离出儿茶素、迷迭香酸、圣草酚、丁香酸、芦丁5种酚类化合物,梅花果实的抑菌和抗氧化活性与总酚和总黄酮含量存在相关关系。‘武藏野’和‘飞绿萼’是优良的抗寒花果兼用梅,果实品质性状较优,可以作为天然抗氧化剂或功能性食品进行开发利用。     

Characterization and discrimination of premium‐quality,waxy, and black‐pigmented rice based on odor‐active compounds

BACKGROUND: Odor‐active compounds have been studied in cooked aromatic rice, but not in specialty rice types that have distinctly different flavors. We analyzed the odor‐active compounds emanating from three different types of specialty rice (premium‐quality, waxy and black‐pigmented) and identified the differences in odor‐active compounds among them. RESULTS: Twenty‐one, 21 and 23 odorants were detected using GC‐O for cooked samples of premium‐quality, waxy and black‐pigmented rice cultivars, respectively. Hexanal was the main odorant in premium‐quality and waxy cultivars; however, waxy cultivars had 16 times higher hexanal odor activity values (OAVs) than premium‐quality cultivars, indicating premium‐quality rice had a less pronounced overall aroma. 2‐Acetyl‐1‐pyrroline was the main contributor to overall aroma in black‐pigmented rice, followed by guaiacol. The three types of specialty rice were clearly discriminated based on the OAVs of their odor‐active compounds using multivariate analyses. Six odor‐active compounds [2‐acetyl‐1‐pyrroline, guaiacol, hexanal, (E)‐2‐nonenal, octanal and heptanal] contributed the most in discriminating the three types of specialty rice. Six very similar superior cultivars of premium rice could likewise be readily separated using aroma chemistry. CONCLUSION: The ability to discriminate the aroma among rice types using the OAVs of the principal odor‐active compounds facilitates our understanding of the aroma chemistry of specialty rice. Copyright © 2010 Society of Chemical Industry     

正丁醇处理对‘粉红女士’苹果贮藏期间挥发性物质的影响

苹果的香气成分是构成苹果品质的重要因素,香气主要由挥发性物质描述,因此研究苹果挥发性物质具有重要意义。本试验为探究正丁醇处理对‘粉红女士’苹果挥发性物质的影响,以‘粉红女士’苹果为试材,分别用10和25 μL·L?1正丁醇溶液处理,采用有机溶剂萃取法提取挥发性物质,并利用气相色谱质谱联用仪（GC-MS）对其香气成分进行分析。结果表明:在各处理的整个贮藏期‘粉红女士’苹果果实中共检测出25种挥发性物质,包括酯类、醇类、醛类、酸类和萜烯类,以酯类和醛类物质为主;随着贮藏时间的延长,果实的挥发性物质种类减少,乙酸戊酯、丁酸丁酯、2-甲基-丙酸己酯、法尼醇和2-甲基丁酸未被检测到;25 μL·L?1处理组果实的乙酸戊酯、丁酸丁酯、2-甲基-丙酸己酯、法尼醇和2-甲基丁酸含量在贮藏第7 d和第14 d时明显高于对照组和10 μL·L?1处理组,此浓度正丁醇的添加能够促进贮藏前期果实挥发性酯类物质的产生。通过气味活性值分析发现有气味活性的化合物有19种,其中呈果香味的乙酸己酯是‘粉红女士’苹果主要的呈香物质。本研究表明,正丁醇的添加影响了‘粉红女士’苹果果实中酯类物质的产生,且25 μL·L?1处理组效果最显著,同时该研究可为‘粉红女士’苹果挥发性物质的研究提供理论基础。     

不同果肉类型枇杷果肉挥发性成分分析

采用顶空固相微萃取和气相色谱-质谱联用技术,分别测定7个白肉品种、15个红肉品种枇杷成熟果肉的挥发性成分,结合聚类分析法和主成分分析法对枇杷果肉挥发性成分进行分析。结果表明:22个品种枇杷成熟果肉检测到醛、萜烯、醇、酮、酯及其他6类挥发性化合物,醛类物质是枇杷果肉的主要挥发性化合物,酯类、酮类和醇类是构成不同品种枇杷特有风味的重要组成,正己醛是相对含量最高的挥发性物质。7个白肉品种枇杷检测出65种挥发性成分,共有挥发性物质14种,莰烯、氧化石竹烯、2-甲基丁酸仅在白肉品种枇杷中检测到;15个红肉品种枇杷检测出81种挥发性成分,共有挥发性物质10种,甜瓜醛、反-2,4-癸二烯醛、反-β-罗勒烯、3-蒈烯、丁二醇、叶醇、十二醇、植酮、乙酸己酯、水杨酸甲酯、丁酸芳樟酯、香叶酸甲酯、乙酸橙花酯、肉桂酸乙酯、百里香酚、丁香油酚是红肉品种枇杷特有的挥发性物质。不同果肉类型枇杷的挥发性成分的主要差异体现在醇类和酯类物质,脱辅基类胡萝卜素类香气物质香叶基丙酮、β-紫罗酮在红肉枇杷中的相对含量明显高于白肉枇杷。聚类分析和主成分分析能把除‘冠玉’和‘乌躬白’外的其他白肉品种枇杷聚集,壬醛是对果肉风味贡献率最高的挥发性物质。