Effects of ultrasonic-assisted extraction on bioactive compounds,volatile flavors and antioxidant activities of vine tea water extracts

Background:Ampelopsis grossedentata,vine tea,which is the tea alternative beverages in China.In vine tea processing,a large amount of broken tea is produced,which has low commercial value.Methods:This study investigates the influence of different extraction methods(room temperature water extraction,boiling water extraction,ultrasonic-assisted room temperature water extraction,and ultrasonic-assisted boiling water extraction,referred to as room temperature water extraction(RE),boiling water extraction(BE),ultrasonic assistance at room temperature water extraction(URE),and ultrasonic assistance in boiling water extraction(UBE))on the yield,dihydromyricetin(DMY)content,free amino acid composition,volatile aroma components,and antioxidant properties of vine tea extracts.Results:A notable influence of extraction temperature on the yield of vine tea extracts(P<0.05),with BE yielding the highest at 43.13±0.26%,higher than that of RE(34.29±0.81%).Ultrasound-assisted extraction significantly increased the DMY content of the extracts(P<0.05),whereas DMY content in the RE extracts was 59.94±1.70%,that of URE reached 66.14±2.78%.Analysis revealed 17 amino acids,with L-serine and aspartic acid being the most abundant in the extracts,nevertheless ultrasound-assisted extraction reduced total free amino acid content.Gas chromatography-mass spectrometry analysis demonstrated an increase in the diversity and quantity of compounds in the vine tea water extracts obtained through ultrasonic-assisted extraction.Specifically,69 and 68 volatile compounds were found in URE and UBE extracts,which were higher than the number found in RE and BE extracts.In vitro,antioxidant activity assessments revealed varying antioxidant capacities among different extraction methods,with RE exhibiting the highest DPPH scavenging rate,URE leading in ABTS•+free radical scavenging,and BE demonstrating superior ferric ion reducing antioxidant activity.Conclusion:The findings suggest that extraction methods significantly influence the chemical composition and antioxidant properties of vine tea extracts.Ultrasonic-assisted extraction proved instrumental in elevating the DMY content in vine tea extracts,thereby enriching its flavor profile while maintaining its antioxidant properties.

Co-Treatment of EFF and 1-MCP for Enhancing the Shelf-Life and Aroma Volatile Compounds of Oriental Sweet Melons(Cucumis melo var.makuwa Makino)

Compared to other melon types, oriental sweet melon （Cucumis melo var. makuwa Makino） is quite a different species with a shorter shelf-life due to its typical climacteric behavior and thin pericarp. The purpose of this experiment is to explore the effects of co- treatment of enhanced freshness formulation （EFF） and 1-methylcyclopropene （1-MCP） on physiological changes and the content of aroma volatile compounds introduced by them of two oriental sweet melon cultivars （Yumeiren and Tianbao） during storage. The melons were stored in incubators with temperature of 15~C and a relative humidity of 85% for 24 d during which fruit quality and related physiological index were measured. Compared to the control, both treatments delayed fruit weight loss rate and kept the fruit firmness, water content and soluble solids content. Ascorbate peroxidase （APX） and phenylalanine ammonia lyase （PAL） activities showed fluctuations in treated melons, while lipoxygenase （LOX） activity （P〈0.01） and malondialdehyde （MDA） content （P〈0.05） decreased compared to control. During the early stage of storage, alcohols and aldehydes were the main volatile compounds, and esters gradually increased during storage. Of all the esters, acetic esters were the main components, followed by oxalic acid esters and other esters. The total content of aroma volatile compounds, esters, alcohols and aldehydes of co-treated melons were all higher than those of 1-MCP treated and control melons. In addition, the aroma volatile peak of co-treated melons occurred later than that of 1-MCP treated and control melons. In summary, co-treatment of EFF and 1-MCP was more beneficial than 1-MCP treatment to delay ripening and senescence, maintain fruit quality, enhance shelf-life and improve levels of aroma volatile compounds.

Analysis of Volatile Compounds and Identification of Characteristic Aroma Components of <i>Toona sinensis</i>(A. Juss.) Roem. Using GC-MS and GC-O

In this study, volatile compounds present in Toona sinensis (A. Juss.) Roem (TS) were investigated and their characteristic aromatic components were identified using Headspace Solid-phase Microextraction (HS-SPME) followed by Gas Chromatography-Mass Spectrometry (GC-MS) and Gas Chromatography-Olfactometry (GC-O). The optimum conditions for extracting the volatiles from TS were achieved with the experimental parameters including the use of a 65 μm polydimethylsiloxane/divinyl benzene (PDMS/DVB) fibre, an extraction temperature of 40℃ and an extraction time of 30 min. Under these conditions, 56 volatile compounds were separated and 53 were identified by GC-MS. Among them, 21 sulfide compounds (42.146%) and 27 terpenes(55.984%) were found to be the major components. The sample was analyzed by GC-O and 26 elutes were sniffed and their sensory descriptions evaluated by an odor panelists. Analysis of the data indicated, two compounds cis and trans isomers of 2-Mercapto-3,4-dimethyl-2,3-dihydrothiophene were major contributors to the characteristic aroma of TS.

Analysis of Aroma Volatile Compounds in Fuji Apple Using SPME with Different Fiber Coatings

The aroma volatile compounds in Fuji apple were isolated by solid-phase microextraction( SPME),and detected by gas chromatography-mass spectrometry( GC-MS). The results showed that the optimal retention time of the heating up of capillary columns was 5 min. Of the seven fibers used in this work,DVB/CAR/PDMS was found to be the most suitable to extract the aroma volatile compounds in Fuji apple. A total number of 43 volatile compounds were identified according to their retention time on capillary columns and their mass spectra,including eleven esters,ten alcohols,ten aldehydes,seven alkenes,two anhydrides,one ketone,one phenol and one ether. This detection method will provide a new foundation for analysis of volatile compounds in apple were identified.

Comparison of Headspace Solid-Phase Microextraction with Simultaneous Steam Distillation Extraction for the Analysis of the Volatile Constituents in Chinese Apricot

Volatile constituents in fully mature fruits of apricot （Prunus armeniaca L.） cultivar Xinshiji were extracted using headspace solid-phase microextraction （HS-SPME） and simultaneous steam distillation extraction （SSDE） and then analyzed using capillary gas chromatography and gas chromatography-mass spectrometry. A total of 70 components were identified by HSSPME, including 20 esters, 19 hydrocarbons, 5 alcohols, 5 ketones, 4 acids, 4 lactones, 3 aldehydes, and 10 miscellaneous components, with the esters being the dominant constituent. On the basis of the odor unit values, it is believed that the following compounds probably contributed to the fresh apricot odor： hexyl acetate, β-ionone, butyl acetate, （E）-2-hexenal, linalool, limonene, γ-decalactone, and hexanal. A total of 49 components were also detected by SSDE, including 13 hydrocarbons, 9 alcohols, 7 aldehydes, 9 esters, 4 ketones, 4 lactones, 2 acids, and 1 miscellaneous component, of which the monoterpene alcohols were the dominant constituents. It could be judged from the odor unit values that the following compounds were the major contributors to boiled apricot aroma： β-ionone, linalool, hexyl acetate, γ-dodecalactone, γ- decalactone, （E）-2-hexenal, hexanal, γ-octalactone, phenylacetaldehyde, butyl acetate, limonene, α-terpineol, and δ-decalactone. The results show that HS-SPME is a simple, rapid, and solvent-free method, which is an alternative to the classical SSDE.

Transcriptome analysis of the influence of CPPU application for fruit setting on melon volatile content

In fruit production,the application of the plant growth regulator 1-(2-chloro-4-pyridyl)-3-phenylurea(CPPU)dulls the fruit aroma.Gas chromatography-mass spectrometry and transcriptome analyses were performed on CPPU-treated and pollinated fruits to determine how CPPU affects the production of aroma in melon fruit.The results showed that the contents of two important esters(benzyl acetate and phenethyl acetate)in the CPPU-treated fruits were significantly lower than those in the pollinated fruits.Transcriptome sequencing data revealed that most differentially expressed genes were involved in“phenylalanine metabolism”pathway,and their expression was significantly decreased in the CPPU-treated fruits.Further analysis showed that the phenylalanine content in the CPPU-treated fruits was significantly higher than that in the pollinated fruits.In summary,CPPU application interferes with phenylalanine metabolism in melon fruits and affects the production of aromatic esters.

GC-MS Analysis of Volatile Components in ‘Changping 8’ Apple Fruit

Solid-phase and micro-extraction combined with GC/MS(SPME-GC-MS) were employed to detect main aroma components in ‘Changping 8’ apple fruit. The results showed that, 29 kinds of compounds were identified from the aroma components in ‘Changping 8’ apple fruit, and they were aldehydes, alcohols, esters, ketones, etc. The main aroma components of apple fruits were acetic acid, hexyl ester, acetic acid, butyl ester,(E)-2-hexenal, 1-butanol, hexanal, and 1-hexanol.

Plant-Derived Enzymes Producing Chiral Aroma Compounds and Potential Application

Aroma(volatile)compounds play important ecological functions in plants,and also contribute to the quality of plant-derived foods.Moreover,chiral aroma compounds affect their functions in plants and lead to different flavor quality properties.Formations of chiral aroma compounds are due to the presence of enzymes producing these compounds in plants,which are generally involved in the final biosynthetic step of the aroma compounds.Here,we review recent progress in research on the plant-derived enzymes producing chiral aroma compounds,and their changes in response to environmental factors.The chiral aroma enzymes that have been reported produce(R)-linalool,(S)-linalool,(R)-limonene,and(S)-limonene,etc.,and these enzymes are found in various plant species.We also discuss the origins of enantioselectivity in the plant-derived enzymes producing chiral aroma compounds and summarize the potential use of plants containing enzymes producing chiral aroma compounds for producing chiral flavors/fragrances.

不同栽培模式对草莓果实挥发性香气物质的影响

为探明不同栽培模式对草莓果实挥发性香气物质的影响,以红颜(HY)、天使8号(TS8H)为试验材料,设置常规土壤栽培和高架基质栽培2种模式进行栽培试验。果实成熟后,采用搅拌棒吸附萃取(SBSE)结合气相色谱-质谱(GC-MS)联用技术对草莓果实的香气成分进行测定与分析。结果表明:2个草莓品种中共检测出83种、12大类挥发性香气物质。其中,脂肪酯29种、内酯3种、芳香族酯6种、脂肪醇4种、萜烯醇5种、呋喃酮2种、脂肪酮3种、萜烯酮2种、脂肪酸6种、脂肪醛8种、萜烯6种、其他9种。香气组分中,内酯、萜烯醇、脂肪酯相对含量较高。常规土壤栽培处理红颜果实内酯、萜烯醇、脂肪酯相对含量分别为46.77%、21.46%、16.18%,天使8号分别为44.20%、25.71%、19.77%;高架基质栽培处理红颜果实内酯、萜烯醇、脂肪酯相对含量分别为51.17%、24.21%、13.10%,天使8号分别为43.59%、18.11%、16.54%。不同栽培模式下,同一品种中90%以上挥发性香气物质种类一致,主要挥发性香气物质均为γ-癸内酯、γ-十二内酯、反式橙花叔醇;高架基质栽培方式下红颜果实γ-癸内酯和天使8号果实4-甲氧基-2,5-二甲基-3(2H)-呋喃酮(DMMF)的相对含量明显高于常规土壤栽培。综上,高架基质栽培在维持草莓果实主要挥发性香气物质稳定的同时,还可以提升果实的果香、甜香味。

高产乳酸耐热克鲁维酵母的筛选及其在葡萄酒中增酸潜力研究

通过比较16株耐热克鲁维酵母(Lachancea thermotolerans)的产乳酸能力及耐受性,筛选高产乳酸的优良菌株,并将其与商业酿酒酵母(Saccharomyces cerevisiae)EC1118按1∶1配比共发酵制备霞多丽葡萄酒,评估其酿造特性。结果表明,耐热克鲁维酵母菌株LT-XJ24、LT-XJ59、LT-ZX03与LT-GS27的耐受性较好,且产乳酸能力较强,在葡萄汁中的乳酸产量分别为6.41 g/L、6.52 g/L、7.89 g/L和6.21 g/L。优选的4株耐热克鲁维酵母与商业酿酒酵母共发酵均能完成霞多丽葡萄酒的酒精发酵,且均具有良好的生物增酸能力,其中菌株LT-ZX03混合发酵的霞多丽葡萄酒中的乳酸产量最高,达6.66 g/L。尽管混合发酵组提高了葡萄酒的挥发酸含量,但仍然符合相关标准要求(≤1.2 g/L)。从霞多丽葡萄酒样品中共检出41种香气物质,包括23种酯类、11种醇类、5种酸类以及2种其他类化合物,其中13种物质的香气活度值(OAV)>1。不同耐热克鲁维酵母对霞多丽葡萄酒中挥发性香气物质的影响存在差异,其中菌株LT-GS27和LT-ZX03影响较大,能够提高葡萄酒中具有花果香气的丁酸乙酯、己酸乙酯、辛酸乙酯和癸酸乙酯等物质含量。

唾液对山西老陈醋香气释放的影响

为研究只含粘蛋白的人工唾液和离体的人唾液对山西老陈醋香气释放的影响,采用顶空固相微萃取(HS-SPME)结合全二维气相色谱-飞行时间-质谱(GC×GC-TOF-MS)联用技术对3种山西老陈醋中挥发性香气成分进行分析。通过聚类分析(CA)比较唾液对3种山西老陈醋挥发性化合物含量的影响,并利用香气活性值(OAV)筛选出山西老陈醋的关键风味物质,通过绘制山西老陈醋的香气轮将香气化合物的含量数据转化为感官描述信息,明确唾液对山西老陈醋感官特征的影响。结果表明,从山西老陈醋中共检出105种挥发性化合物,在2种类型唾液的影响下,65种挥发性化合物的含量均显著降低(P<0.05),特别是酯类和酮类,OAV>1的27种关键香气化合物中将近一半化合物的OAV均减少了10%以上,说明唾液会影响山西老陈醋的感官特征。2种类型的唾液均会减弱山西老陈醋香气化合物的感官属性,尤其是对坚果味、奶香味和花香味。该研究明确了唾液对山西老陈醋的香气释放有影响,为提升山西老陈醋的感官体验提供了理论依据。

早青与晚青乌龙茶的挥发性成分差异

为探明鲜叶不同采摘时段对乌龙茶香气化学特征的影响,本研究将铁观音早青与晚青按传统工艺加工成乌龙茶,运用气相色谱-质谱法分析鲜叶和乌龙茶的挥发性成分,比较早青茶与晚青茶中挥发性成分的差异。结果表明,晚青茶所含挥发性组分总量比早青茶少28.3%,醇类化合物的含量及占比均处优势,尤其是异植醇和反-橙花叔醇。挥发性成分在鲜叶与乌龙茶中的组成特征差异较大,醇类和酸类化合物在鲜叶中的占比相近,但在乌龙茶中二者差异较大;早青与晚青包含56种共有挥发性成分,比其乌龙茶的共有成分多4种,但在鲜叶与乌龙茶共有42种成分中十六烷酸、二氢猕猴桃内酯、反-橙花叔醇、异植醇等受加工工艺的影响明显,且变化幅度较大。可见晚青与早青中挥发性成分的分布特征相异,晚青茶优于早青茶且清香突出。

微波预处理对加热卷烟用烤烟烟叶常规化学成分及挥发性香气成分的影响

以河南产区的下部烤烟样品为原料,采用微波干燥和微波水热两种方法预处理原料,利用连续流动分析、高效液相色谱、气相色谱-离子迁移谱(GC-IMS)等技术对不同微波预处理烤烟烟叶中的常规化学成分及挥发性香气成分进行分析。结果表明:微波水热处理可降低烤烟烟叶中水溶性糖、还原糖、植物碱及酚类物质含量,提高总氮、石油醚提取物含量,并显著增加烤烟原叶的氮碱比(P≤0.05),其中微波水热700 W-6 min处理组氮碱比高达1.65;而经微波干燥处理后,烤烟烟叶中常规化学成分整体仍处于优质烟叶指标范畴,且挥发碱含量显著增加(P≤0.05),部分预处理组中绿原酸和芸香苷含量增加;此外,GC-IMS共鉴定出56种挥发性香气成分,微波水热处理可增加烤烟的新鲜清香,微波干燥处理则可增加其甜香味。

苹果等6种经济林不同时期果实BVOCs成分分析

为探究常见经济林树种不同时期果实在自然状态下释放植物源挥发性有机物(BVOCs)组成成分差异,并分析其香气类型,选取苹果、桃、李、梨、山楂和枣6种经济林树种为研究对象,采用动态顶空采集法收集释放的BVOCs,结合自动热脱附-气相色谱/质谱联用技术进行BVOCs分析。结果表明,6种果实膨大期和成熟期均检测出12类BVOCs,组分总数量前者(305)大于后者(275),2个时期果实释放烷烃类、烯烃类、芳香烃类、酯类和醛类BVOCs占比最大;不同时期6种果实有10种共有BVOCs为2,2,4,6,6-五甲基庚烷、正十九烷、a-柏木烯、正戊醛、庚醛、辛醛、天然壬醛、癸醛、苯乙酮和庚胺醇;苹果、桃、李和梨随着果实生长发育BVOCs成分数量减少;不同时期6种果实香韵涵盖香型有差异,并随果实生长发育,青草香、果香、檀木香、醛香和柑橘香占比明显增加。表明不同时期6种经济林植物果实释放BVOCs组成成分和相对含量差异明显,在果实成熟期,主要香气BVOCs成分相对含量较高,是果实香精开发的最佳时期。

橄榄果实表型性状分级及挥发性化合物鉴定与特征香气分析

对59个品种(系)橄榄果实表型性状(单果质量、纵径、横径、果形指数)进行测定分析和概率分级,筛选果形指数级别不同且遗传背景不同的15个品种(系)橄榄果实,采用顶空固相微萃取和气相色谱-质谱联用技术进行挥发性化合物的分离鉴定。结果表明:4个表型性状的变异丰富,变异系数范围为10.70%~26.67%;经K-S检验,果形指数、纵径、横径符合正态分布,并对这3个表型性状进行概率分级;橄榄果实中共鉴定到886种挥发性化合物,包括萜类186种、杂环类157种、酯类146种、酮类73种、烃类64种、醇类64种、醛类53种、芳烃51种、酸类21种、胺类21种、酚类20种、其他30种,含量1881.70~6727.40μg/g(以鲜质量计,下同);萜类为主要的挥发性化合物,相对含量52.49%,含量最高的为α-蒎烯(309.66μg/g),相对含量7.13%;香气活性值(odor activity value,OAV)分析表明,对橄榄具有香气贡献的特征香气成分为181种,贡献最高的为杂环化合物5-乙基-3-羟基-4-甲基-2(5H)-呋喃酮,OAV为2468148.28,呈甜香型;进一步通过主成分分析结合正交偏最小二乘判别分析,筛选到不同品种(系)橄榄果实的差异特征香气成分6种,变量投影重要性值最高的是α-法呢烯,OAV为19.71,香气类型花果香。研究结果可为橄榄果实品质质量分级提供依据,也为深入研究橄榄果实香气形成机制、果实品质改善提供了参考依据。

6种武陵酱香型白酒中挥发性含硫化合物差异分析

挥发性含硫化合物由于具有香气特征强、阈值低的特点,对食品风味具有十分重要的影响。然而大多数挥发性含硫化合物在食品中的含量低于气相色谱-质谱联用(G C-MS)分析技术的检出限,难以被鉴定和识别。酱香型是我国白酒的主要香型,产于湖南的武陵酱香型白酒是酱香型白酒的重要代表之一。为深入探究我国酱香型白酒中重要的痕量挥发性含硫化合物的组成,研究采用顶空固相微萃取结合全二维气相色谱-硫化学发光检测(GC×G C-SCD)技术,以6种不同类型武陵酱香型白酒为研究对象,对其中的含硫化合物进行了分析。研究共定性鉴定出27种含硫化合物,其中共有含硫化合物19种,非共有含硫化合物8种,主要包括4种硫醇、6种硫酯、5种多硫醚、5种噻唑、6种噻吩、1种噻烷;对其中信噪比大于100的23种含硫化合物,采用外标曲线法进行了定量分析。依据定量分析结果,采用主成分分析和正交偏最小二乘判别分析,研究确定了6种不同类型武陵酱香型白酒中挥发性含硫化合物含量的差异;14种变量投影值大于1的含硫化合物,可作为区分6种不同类型武陵酱香型白酒风味特征的差异组分。希望研究可为酱香型白酒的调配提供数据参考,为白酒企业调控生产过程、提高产品质量提供帮助。

基于代谢组学方法的冬桑复合茶化学成分比较分析

目的基于代谢组学方法系统解析冬桑复合茶(mulberry-leaf teas,MTs)关键化学成分,并通过与感官结果结合阐明其中潜在风味成分。方法本研究采集了市售冬桑、绿茶、乌龙茶和红茶原料,冬桑绿茶复合茶、冬桑乌龙茶复合茶和冬桑红茶复合茶样本。采用搅拌棒吸附萃取(stir bars orptive extraction,SBSE)富集样品中的挥发性成分,热解析附后,采用气相色谱-质谱法(gas chromatography-mass spectrometry,GC-MS)进行分析,并采用基于超高效液相色谱-串联四极杆飞行时间质谱法(ultra performance liquid chromatography-tandem quadrupole time-of-flight mass spectrometry,UPLC-QToF/MS)的代谢组学技术全面解析MTs的关键香气成分及非挥发性品质成分。结果冬桑绿茶中β-环柠檬醛、橙花醇和2-甲基丁酸顺式-3-己烯酯,冬桑乌龙茶中2-壬烯醛、苯甲醛、香叶醛和芳樟醇,冬桑红茶中芳樟醇、脱氢芳樟醇、4-萜品醇、α-松油醇、橙花醇和香叶醇等香气成分是构成复合茶的香气关键成分。此外,共鉴定出73个黄酮类、36个有机酸类、21个脂类、18个萜类和苯丙烷类、15个糖类、8个生物碱类、7个氨基酸类以及5个脂溶性色素类成分,筛选出15个变量投影重要性指标大于1的特征性成分,特别是(+)-没食子儿茶素、槲皮素3-O-槐糖、原花青素C1、表没食子儿茶素没食子酸酯、表儿茶素(4α-8)儿茶素、槲皮素3,7-糖苷、二氢杨梅素、山奈酚-3-鼠李糖苷、dTDP-6-脱氧-D-糖、D-岩藻糖、二羟基-1(10)-螺环戊烯-2-酮11-糖苷、PI(16:0/18:2(9Z,12Z))、PG(16:0/18:3(6Z,9Z,12Z))(L10)、对羟基奎尼酸、抗坏血酸等桑叶特征性成分,这些非挥发性成分是直接或间接贡献复合茶滋味的关键成分。结论本研究系统解析了传统茶与冬桑叶拼配的复合茶关键风味物质基础及其对特征风味品质的潜在贡献,为优化茶与冬桑复合配方提供科学依据,拓展茶跨界组合应用提供理新思路。

产香酵母的筛选及其在液态食醋酿造中的应用

从传统食醋酿造酒曲中分离获得一株产香酵母HQ9,摇甁培养总酯产量达(7.46±0.87)g/L,鉴定为光滑假丝酵母(Candida glabrata)。研究发现,菌株HQ9具有乙醇发酵能力,并且能够在300 g/L葡萄糖、200 g/L乙醇环境中正常生长代谢。以酿酒酵母JM12为对照,考察了菌株HQ9应用于米醋酿造对米醋风味品质的影响。结果显示,两菌株酒精发酵制得米醋样品中有机酸、挥发物组成及含量差异明显。菌株HQ9发酵米醋中酯类和醇类等香气物质更加丰富,乙酸异丁酯、乙酸异戊酯、乙酸丁酯、乙酸乙酯等含量较高;米醋样品总酸达到(42.6±0.3)g/L,总酸中柠檬酸[(1.65±0.05)g/L]、苹果酸[(0.43±0.08)g/L]和琥珀酸[(0.78±0.06)g/L]等非挥发性酸比例显著增加。感官品评结果显示,米醋刺激性减弱,口感更加柔和,表明菌株HQ9应用于液态食醋酿造能够改善提升产品风味品质,是一株具有工业应用潜力的生产菌株。

铁观音中降解β-胡萝卜素菌株的筛选及其陈香提升应用

陈香型铁观音具有独特陈香风味,但其自然陈化周期漫长,提高铁观音的陈香品质并缩短陈化周期具有重要的经济和文化价值。从铁观音中筛选获得3株具有β-胡萝卜素降解能力的菌株并鉴定为Aspergillus niger(HA)、Bacillus velezensis(Hb)、Saccharopolyspora gregorii(Hc),它们的降解率分别为94.54%、72.97%、61.26%。将菌株投入茶叶进行强化发酵,并测定发酵结束后茶叶的挥发性物质含量和感官品评得分。结果表明,HA和Hb发酵茶样含量提升幅度最大的是酮类化合物,分别提升了128.12%和109.38%;Hc发酵茶样醛类化合物提升幅度最大为61.11%,发酵茶样中的类胡萝卜素降解产物总量也分别提升了1.6、1.4、1.3倍。发酵茶样总体评价均高于对照,同时HA发酵茶样的甜香得分提高,Hb发酵茶样的果香得分提高,Hc发酵茶样的甜香和陈香得分提高。该研究筛选出一株降解β-胡萝卜素的Saccharopolyspora gregorii,成功在短期内实现了铁观音陈香品质的提升。

基于电子鼻和GC-IMS技术分析储藏时间对酱香型白酒挥发性风味物质的影响

该研究以第四轮次新酿、储藏1年和3年的酱香型白酒为研究对象,采用电子鼻和气相色谱-离子迁移谱(gas chromatography-ion mobility spectroscopy,GC-IMS)技术对其挥发性风味物质进行解析,探讨储藏时间对酱香型白酒挥发性风味物质的影响。电子鼻结果表明,传感器W3C(对氨气、芳香类物质灵敏)、W5C(对烷烃、芳香类物质灵敏)、W1W(对有机硫化物、萜类物质灵敏)和W2S(对乙醇灵敏)对不同储藏时间的酱香型白酒响应值存在显著差异(P<0.05),且对储藏3年的酱香型白酒响应值最高。结合相对气味活度值(raletive odor activity value,ROAV)法和变量投影重要性(variable importance in projection,VIP)分析,GC-IMS结果表明,己酸乙酯、戊酸乙酯、异戊酸乙酯、乙酸戊酯和异丁醛是对酱香型白酒风味贡献较为突出的关键化合物,异戊酸乙酯和异丁酸乙酯对不同储藏时间酱香型白酒之间风味贡献差异显著(P<0.05),且对储藏3年酱香型白酒香气贡献更大。3-甲基-1-丁醇、糠醛、异戊酸乙酯、2-甲基丁酸乙酯、乙酸乙酯和异丁酸乙酯是不同储藏时间酱酒中的关键差异化合物,且在储藏3年酱酒中相对含量更高。由此可知,储藏对酱酒风味品质形成具有积极意义,且储藏3年的酱香型白酒整体风味更为突出。