黄桃酒发酵过程中风味物质的变化

为了研究黄桃酒发酵过程中风味物质动态变化,本研究采用顶空固相微萃取(HS-SPME)结合气相色谱-质谱联用(GC-MS)技术分析风味物质,结合香气活力值(OAV)确定主要风味物质。结果表明,发酵7 d制备的黄桃酒,酒精度14.50%(v/v)、总酸31.54 g/L、可溶固形物12.37 °Brix、总黄酮1.08 g/L。感官评价表明,所制备黄桃酒保留了桃果实的清香,同时又有酒的醇香和酯香。顶空固相微萃取-气相色谱与质谱联用(HS-SPME/GC-MS)结合分析得到:发酵过程中共检测出70种风味物质,含量较多的是酯类(29种)、醇类(15种);发酵过程中风味物质种类变化不大,但每类风味物质含量却有较大变化。酯类、醇类物质含量在主发酵过程中呈递增趋势,后熟时趋稳;醛类、酮类和酸类物质含量逐渐减少。通过计算香气活力值(OAV)确定16种物质对黄桃酒风味贡献较大,其中辛酸乙酯、γ-癸内酯和右旋萜二烯对黄桃酒香气贡献最大,活力值大于20。在发酵过程中,酯类、醇类物质的增加赋予黄桃酒浓郁的酒香,同时保留了黄桃的特征香气物质。     

Identification of key odor volatile compounds in the essential oil of nine peach accessions

BACKGROUND: Volatile compounds, together with sugars and acids, are the main chemical species determining the characteristic aroma and flavor of food. In peach, more than 100 volatiles have been identified. RESULTS: The essential oil of six peach and three nectarine accessions used in Italian breeding programs was obtained by steam distillation, and the volatiles were investigated. A total of 47 known volatiles, two unidentified compounds and nine hydrocarbons were identified, including 12 aldehydes, six alcohols, three acids, three esters, six terpenes, two phenylalanine derivates, two C₁₃ norisoprenoids, one ketone (C₉) and 10 lactones. A wide variation in the number of volatiles and in their concentration was observed among the nine accessions. Twenty‐one compounds presented odor activity values (OAVs) higher than 1 in at least one of the accessions and were therefore putatively considered as key odorants in the peach volatile composition. CONCLUSION: This study reports the identification, quantification and potency, based on the OAVs, of the most important volatile compounds, along with fruit quality characteristics, of nine different peach/nectarine accessions and will help future peach volatile breeding programs for the selection of odor‐rich accessions to be used in the development of new improved cultivars. Copyright © 2010 Society of Chemical Industry     

Ester-related volatile compounds reveal the diversity and commonalities of different types of late-ripening peaches

To recognize the key ester-related volatile compounds, 5 types of peaches including 54 late-ripening peach materials were examined by headspace solid-phase microextraction coupled with gas chromatography–mass spectrometry and E-nose. Here, a large number of esters were identified to be released by ripe peach fruits and were mainly characterized by fruity, green, and fatty notes. The variety and content of esters had greatly changed within or between cultivars, indicating that the fruit volatiles were highly differentiated depending on the specific genotypes and cultivation conditions. The ester types showed that fatty acid-derived C6 alcohols and methyl-/ethyl- short-chain alcohol were the main ester precursors, which were more likely to be utilized and well selected by alcohol acyltransferases, whereas the preference of acyl donors was not observed. The common peach type, which exhibited a unique volatile profile, displayed broader diversity and more abundant characteristics in ester-related volatiles than the other four types. A total of 19 key esters were identified as the main components and the content of most esters showed no significant difference among different peach types. Some key esters had even been enriched in nectarines. Moreover, the multiple discriminant analysis revealed a possible relationship between peach types and the domestication of the peach evolution. This study investigated ester-related volatiles released by different types of peach fruits and can be further used to evaluate the peach qualities, providing an important reference for peach breeding and processing.     

桃花中营养及功能性成分分析

目的对不同颜色桃花的营养物质和功能性成分进行分析测定,以明确桃花的化学组成。方法对桃花水提液、乙醇提取液和石油醚提取液中组分进行系统定性鉴定,并在此基础上对白色、粉色、红色三种桃花中的蛋白质、还原糖、总酚、总黄酮、花色苷含量和氨基酸及酚类物质组成进行分析。结果桃花中含有糖、蛋白质(氨基酸)、有机酸、酚类物质、游离黄酮及其苷类、皂苷、生物碱等,其中总糖含量为31.99%~34.53%,还原糖含量为18.20%~24.44%,可溶性蛋白含量为6.48%~8.19%,氨基酸含量为9.68%~12.02%,总酚含量为7.30%~9.03%,总黄酮含量为3.89%~4.69%,粉色和红色桃花中含有花色苷,含量为2.35%~9.29%,白色桃花不含花色苷;不同种类桃花具有不同的氨基酸组成和酚类物质组成。结论桃花富含营养物质与功能性成分,是一种很有开发利用价值的植物资源。     

乳酸菌发酵蜜桃果酱过程中风味物质变化规律研究

目的 探究乳酸菌发酵制备蜜桃果酱过程中挥发性风味物质变化规律,进而筛选出特征香气化合物。方法 采用顶空-气相色谱-离子迁移谱技术(headspace-gas chromatography-ion mobility spectrometry, HS-GC-IMS)分析乳酸菌混合发酵蜜桃果酱制作过程中不同时期挥发性风味物质变化规律,并结合主成分分析、偏最小二乘判别分析进行统计学分析。结果 共检测到60个信号峰,鉴定出挥发性化合物32种,包括醛类、酮类、醇类、酯类等。其中,醛类化合物种类最丰富。通过多元统计学方法,实现了蜜桃果酱制作不同时期的很好区分,特别是发酵阶段明显与未发酵阶段不同,并筛选出17种特征性风味物质,如2,3-丁二酮、壬醛,赋予蜜桃果酱较好的风味特性。感官特性方面,乳酸菌的添加改善了果酱的适口性,酸甜度更容易接受。结论 HS-GC-IMS可以有效用于发酵型果酱制作过程的品质评价,该研究结果为乳酸菌发酵水果制品的品质调控提供了新的分析方法和重要科学依据。     

乳酸菌发酵蜜桃果酱制作过程中理化性质和关键香气成分演化研究

目的 探究乳酸菌发酵蜜桃果酱制作过程中的品质特性及挥发性香气化合物变化情况,进一步筛选关键呈香物质。方法 采用顶空固相微萃取-气相色谱-质谱法测定乳酸菌发酵蜜桃果酱挥发性风味物质变化。同时, 测定样品的总多酚、总黄酮、有机酸、色泽等理化指标, 并进行感官方面的评定。结果 共检测到53种挥发性有机化合物, 其中醛类、酯类、醇类在蜜桃果酱中丰富。结合气味活度值(odor activity value, OAV>1), 初步筛选出芳樟醇、1-辛烯-3-醇、壬醛等10种关键呈香物质。在乳酸菌发酵过程中, 果酱样品的总多酚、总黄酮含量显著增加(P<0.05), DPPH自由基清除能力有所提高。但是, 浓缩(NS)和后杀菌(GZ)过程对热敏性物质破坏严重, 颜色接受度下降, 色泽参数(L*、a*、b*)出现明显变化。在发酵过程中, 乳酸-苹果酸含量变化具有相关性。对不同制作时期果酱的挥发性风味物质进行偏最小二乘回归分析, 各时期得以很好的区分, 且模型可靠。结论 乳酸菌发酵改善了蜜桃果酱的风味,明显提高活性物质的含量。     

不同挥发性物质对桃果实品质及抗氧化活性影响的多变量分析

采用单因素方差分析、主成分分析、相关性分析、偏最小二乘回归分析、通径分析5种数据分析方法考察1-甲基环丙烯(1-MCP)、二氧化氯、百里酚和乙醇处理对桃果实品质及抗氧化活性的作用效果。结果表明：乙醇处理可显著抑制常温贮藏4d后桃果实侵染性病害的发生,其他处理与空白对照无显著性差异;1- MCP 处理延缓了桃果皮b*值的升高,乙醇处理提高果皮L*值的同时降低了果皮a*值;与空白对照相比,乙醇、1-MCP及二氧化氯处理对总黄酮含量、总抗氧化能力、清除DPPH自由基能力、清除·OH能力4个指标的影响较为显著。结合相关性分析与回归分析可知,腐烂率仅与可溶性固形物含量(SSC)呈显著负相关;对果皮L*值、果皮a*值、果皮b*值的直接效应最为强烈的参数分别是总黄酮含量、清除DPPH自由基能力、SSC;总酚含量与清除DPPH自由基能力具有显著正相关性;总黄酮含量与总抗氧化能力、清除DPPH自由基及·OH能力也存在显著或极显著相关性效应。     

不同产地桃胶无机元素的ICP-MS分析与评价

目的:建立电感耦合等离子质谱(ICP-MS)测定桃胶中20种无机元素的方法,并进行主成分分析,比较不同产地间桃胶无机元素的差异。方法:采用湿法消解,ICP-MS测定10个产地桃胶的20种无机元素含量,并对其进行主成分分析及评价。结果:方法学考察表明,精密度、重复性、稳定性的RSD值分别为0.4%~2.6%、0.4%~6.2%、0.5%~3.6%,样品在3 h内稳定性良好。各元素回收率在88.7%~107.8%之间,RSD为0.9%~3.7%,表明方法具有可靠性;10个产地桃胶的无机元素种类基本相似,K含量最高,其次为Mg,而K、P、Sr、Ba四种元素产地差异较大,10个产地重金属元素含量均低于限定标准。相关性分析表明,28对元素有相关性,其中4对元素呈极显著正相关(P<0.01),24对元素呈显著正相关(P<0.05)。经主成分分析,前4个主成分因子累积方差贡献率为85.757%,可作为综合评价标准,V、Li、Ge、Sr、P、Mg、Fe、Mn、Co、K为桃胶的特征元素,最终得出福建屏南、浙江苍南、江苏无锡三个产地桃胶的综合得分较高。结论:电感耦合等离子质谱(ICP-MS)法分析速度快、灵敏度高,可用于桃胶中无机元素的含量测定,并为桃胶的质量控制与安全评价提供了参考依据。     

Characterization of Additional Volatile Flavor Components of Apricot

The volatile components of apricot variety “Rouge du Roussillon” were isolated by vacuum distillation and fractionated on silica gel. Analysis by combined gas chromatography-mass spectrometry led to identification of several compounds identified for the first time from this product. These compounds included p-hydroxybenzaldehyde, p-methoxybenzaldehyde, (3-phenyl propyl)-propyl or isopropyl ketone, 3-nonene-2-one, damascenone, β-ionone, dihydroactinidiolide, 2-phenylethanol, cis rose oxide and nerol oxide. The formation mechanism of these compounds is envisaged. Fractions isolated by chromatography on silica gel and head space concentration on Chromosorb 105 were sniffed and analyzed by gaz chromatography. The results obtained indicate that aroma of apricot is due to the presence of compounds such as benzaldehyde, linalool, 4-terpinenol, α-terpineol and perphaps 2-phenylethanol which are responsable for the floral and fruity part of the aroma. Lactones previously identified are “background” compounds as in Cling peach.     

固相微萃与GC/MS联用分析水蜜桃挥发性成分

采用固相微萃取技术萃取新鲜和腐败的水蜜桃挥发性成分,并通过气相色谱质谱联用法来分析、鉴定水蜜桃中的气味成分。经NIST质谱数据库检索和文献对照,新鲜水蜜桃检测出32种成分,占总峰面积的81.48%;腐败的水蜜桃检测出27种成分,占总峰面积的86.56%。相同成分有辛酸乙酯、4-癸酸乙酯、辛酸己酯、1,2-苯二羧基酸丁辛酯、异丙基棕榈酸酯、4-(2,6,6-三甲基)-2-丁酮、5-乙二氢基-2(3H)呋喃酮、十五烷、十六烷、十七烷等20种物质,但其相对含量存在很大差异。结果表现出水蜜桃不同品质果实气味成分的不同,可应用于果实的质量鉴定。