葡萄主要香气物质遗传调控研究进展

【目的】葡萄是重要的经济作物之一,香气是构成葡萄果实品质的重要组分之一。葡萄香气复杂,由包括萜烯类化合物、挥发性脂肪族化合物、芳香族化合物、吡嗪类化合物以及含硫化合物等多种化合物构成,同时受多因素影响。遗传是影响其香气分布的主要因素,选育不同香气类型的葡萄品种是目前重要的育种目标之一,因此分析葡萄香气物质遗传模式是实现育种目标的基础。【评论】本文在综述葡萄香气测定方法的基础上,对葡萄果实香气性状遗传规律、香气性状的QTL定位研究进行归纳与分析。【展望】以期为未来葡萄香气遗传规律解析奠定理论支撑,为葡萄香气性状定向育种提供参考。     

不同地域黄枝香乌龙茶的香气化学组成

用气相色谱／质谱联用法分析了高香型乌龙茶凤凰单枞—黄枝香在不同地域的香气化学组成．结果表明,不同地域样品香气化合物在检测的种数上差异不大,但类别及含量则有明显差异．黄枝香从山地引种于平地种植后,在其香气化合物中未能检测到乌龙茶的主要赋香成分——吲哚和茉莉酮,此外,橙花叔醇亦只有痕量检出,初步认为凤凰名枞—黄枝香存在着明显的地域香．     

The glycosidic aroma precursors in wine: occurrence,characterization and potential biological applications

Wine aroma is defined as the cumulative effect of smell, taste and mouth-feel. Free and glycosidically bound aroma compounds (GBAC) were found in wine. The glycosidic aroma precursors are non-odorous. Most advances have been made in free aroma compounds from wine in recent decades. However, the glycosidically bound aroma compounds have received much less consideration than free aroma compounds. Acids and enzymes are responsible for transferring these glycosidic aroma precursors to aromatic compounds. This review provides an overview of recent developments in isolation, hydrolysis and characterization for glycosidic aroma precursors in wines, as well as their biological applications. It looks like that the GBAC had important biological applications, such as, genetic engineering, immobilization, aroma enhancement and biosynthesis. It will help to better understand the GBAC and free aroma compounds of wines.     

Preparation of reminiscent aroma mixture of Japanese soy sauce

To prepare an aroma mixture of Japanese soy sauce by fewest components, the aroma concentrate of good sensory attributes was prepared by polyethylene membrane extraction, which could extract only the volatiles with diethyl ether. GC-MS-Olfactometry was done with the aroma concentrate, and 28 odor-active compounds were detected. Application of aroma extract dilution analysis to the separated fraction revealed high flavor dilution factors with respect to acetic acid, 4-hydroxy-2(or5)-ethyl-5(or2)-methyl-3(2H)-furanone (HEMF), 3-methyl-1-butanol (isoamyl alcohol), and 3-(methylsulfanyl)propanal (methional). A model aroma mixture containing above four odorants showed a good similarity with the aroma of the soy sauce itself. Consequently, the reminiscent aroma mixture of soy sauce was prepared in water. The ratio of acetic acid, HEMF, isoamyl alcohol, and methional was 2500:300:100:1.     

酱香型与清香型白酒发酵过程中乳酸菌菌群的差异性分析

【目的】为认识乳酸菌在中国白酒酿造过程中的作用与影响, 分析、比较了酱香型与清香型白酒发酵过程中乳酸菌的菌群结构及其差异。【方法】运用PCR-DGGE技术分析酱香型与清香型白酒发酵过程中乳酸菌群的演变规律。并利用传统微生物分离筛选方法进一步确定酱香型白酒发酵中的主要乳酸菌种。【结果】DGGE图谱表明, 白酒发酵过程中的主要乳酸菌种是乳杆菌。但两种香型白酒发酵过程中乳酸菌群组成及动态变化均呈现出明显的差异。清香型白酒酒醅中Lactobacillus fuchuensis是优势菌种, 而酱香型白酒发酵中检测到多种含量较高的乳酸菌种。利用MRS培养基从酱香型白酒酒醅中共筛选获得5种乳酸菌种。通过两种方法, 确定Lactobacillus homohiochii是酱香型白酒发酵过程中含量最高的乳酸菌。【结论】深入研究白酒发酵过程中乳酸菌的组成及分布规律, 对于更好地认识中国白酒酿造中主要的细菌类群——乳酸菌的作用, 具有重要的理论意义和实践价值。     

河南栽培罗勒和丁香罗勒的香气成分差异分析

目的:分析河南栽培罗勒(Ocimum basilicum L.)和丁香罗勒(Ocimum gratissimum L.)成龄叶香气成分的差异。方法:于2015年7月在云南师范大学呈贡校区随机采取长势健壮、无病虫害的河南栽培罗勒和丁香罗勒的成龄叶(自下而上第5、6片叶),采用气相色谱-质谱联用(GC-MS)进行检测;根据峰面积归一化法测定各个组分的相对百分含量。结果:河南栽培罗勒中检出24种香气物质,丁香罗勒中有26种。其中,1,3-二甲氧基苯、石竹烯、乙苯等是2种罗勒共有的主要香气成分。香叶醛、β-蒎烯、薄荷二烯是河南罗勒的主要特有香味成分;蒿脑、桉树脑及异龙脑是丁香罗勒的特有成分。结论:河南栽培罗勒和丁香罗勒种的叶片中香气成分的种类和含量存在明显差异。     

Aroma Components Characteristic of Spring Green Tea

To investigate the aroma components characteristic of spring green tea, analysis of the aroma concentrates of green tea and fresh tea-leaves was accomplished. The research on the changes in aroma constituents of spring green tea and the aroma concentrate from fresh tea-leaves during storage, showed that cis-3-hexenylhexanoate and cis-3-hexenyl-trans-2-hexenoate contributed to the typical fresh aroma of spring green tea. Twelve isomers of hexenol esters were synthesized for comparison of the fresh green note.     

The Occurrence of Quinic Acid in Sweet Potato Roots

The aroma extract dilution analysis of an extract prepared from pork stock and subsequent experiments led to the identification of 15 aroma-active compounds in the flavor dilution factor range of 64–2048. Omission experiments to select the most aroma-active compounds from the 15 odor compounds suggested acetol, octanoic acid, δ-decalactone, and decanoic acid as the main active compounds contributing to the aroma of pork stock. Aroma recombination, addition, and omission experiments of these four aroma compounds in taste-reconstituted pork stock showed that each compound had an individual aroma profile. A comparison of the overall aroma between this recombined mixture and pork stock showed strong similarity, suggesting that the key aroma compounds had been successfully identified.     

成熟度对印度块菌香气成分的影响

研究成熟度对印度块菌Tuber indicum香气成分的影响,并测定成熟印度块菌的关键香气成分。将3种不同成熟度的印度块菌,以固相微萃取(SPME)技术为香气富集方法,利用气相色谱-质谱联用(GC-MS)分析其香气成分。结果表明未成熟印度块菌中仅检测出4种香气成分,中度成熟阶段检测出8种,成熟阶段检测出13种,而且成熟阶段检测出的香气成分大多都是前人报道过对块菌香气有贡献的成分;通过计算成熟块菌各香气组分的香气活度值(OAV),可知二甲基硫醚、2,3-丁二酮、3-甲基正丁醛、2-甲基正丁醛、己醛、1-辛烯-3-醇这6种物质是印度块菌的关键香气成分(OAV>1)。     

SENSORY QUALITY STUDIES ON MANGO AROMA CONCENTRATE DURING STORAGE

Aroma concentrates from Alphonso and Totapuri mango pulps were prepared and the aroma stripped pulps were concentrated two folds. Ready to serve beverages were prepared from fresh mango pulps and pulp concentrates by adding different levels of aroma concentrates. Sensory evaluation of beverages showed that in the case of Alphonso mango addition of 50%, 75% and 100% aroma concentrate gave comparable quality while with Totapuri only 50% level showed comparable quality. The aroma stripped pulp concentrates were canned as such and after mixing with 50% aroma concentrates and stored at 25 × 5°C. Aroma concentrates were bottled and stored at 2°C. At different intervals of storage, beverages were prepared and evaluated. The results showed that throughout the storage period, beverages prepared from mango concentrates to which 50% aroma was added before canning was superior to those prepared from aroma stripped canned pulp concentrates to which aroma was added at the time of preparation of beverage indicating the effect of mango pulp on aroma stability.     

Evaluation of the key odorants of foods by dilution experiments, aroma models and omission.

The state of the art in aroma analysis is reviewed with emphasis on aroma-recombination studies using synthetic blends of odorants (aroma models) which have been prepared on the basis of analytical data. The model that matches the original aroma is the starting material for omission experiments which are performed to establish the odorants that actually contribute to the aroma. These experiments are discussed in detail for the aromas of two wine varieties, three olive oils of different provenance, French fries, boiled beef and coffee. The results indicate that odorants with higher odour activity values (OAV, the ratio of the concentration to the odour threshold) are frequently essential for the aroma. However, there are exceptions where odorants with high OAVs are suppressed in the aroma and compounds with lower OAVs are important contributors. These findings are discussed in the light of model experiments which have been reported in the literature to obtain an insight into the perceptual interactions of odorants in mixtures.     

Aroma barrier properties of sodium caseinate-based films

The mass transport of six different aroma compounds (ethyl acetate, ethyl butyrate, ethyl hexanoate, 2-hexanone, 1-hexanol, and cis-3-hexenol) through sodium caseinate-based films with different oleic acid (OA)/beeswax (BW) ratio has been studied. OA is less efficient than BW in reducing aroma permeability, which can be attributed to its greater polarity. Control film (without lipid) and films prepared with 0:100 OA/BW ratio show the lowest permeability. OA involves a decrease in aroma barrier properties of the sodium caseinate-based films due to its plasticization ability. Preferential sorption and diffusion occurs through OA instead of caseinate matrix and/or BW. The efficiency of sodium caseinate-based films to retain or limit aroma compound transfers depend on the affinity of the volatile compound to the films, which relates physicochemical interaction between volatile compound and film. Specific interactions (aroma compound-hydrocolloid and aroma compound-lipid) induce structural changes during mass transfer.     

Influence of age of mycelium and water activity of the medium on aroma production by Trichoderma viride grown on solid substrate

The production of 2-heptanone (cheese aroma) by Trichoderma viride TS cultivated on agar media was evaluated using headspace gas chromatographic analysis. The radial growth rate of the filamentous fungi increased with high water activity values, but the mycelial density was higher for lower water activity. Maximum aroma production of a culture was obtained at a_w = 0.96. An apparatus intended to measure the aroma production of different areas of a mycelial colony was set up. The study of the aroma production of these areas showed that the production values were greatly different and were evolving with time. It was shown that the mycelium aroma production was maximum when mycelia were about 3.5 to 6.5 d old.     

Mechanistic mathematical model for in vivo aroma release during eating of semiliquid foods

The paper describes a mechanistic mathematical model for aroma release in the oropharynx to the nasal cavity during food consumption. The model is based on the physiology of the swallowing process and is validated with atmospheric pressure chemical ionization coupled with mass spectrometry measurements of aroma concentration in the nasal cavity of subjects eating flavored yogurt. The study is conducted on 3 aroma compounds representative for strawberry flavor (ethyl acetate, ethyl butanoate, and ethyl hexanoate) and 3 panelists. The model provides reasonably accurate time predictions of the relative aroma concentration in the nasal cavity and is able to simulate successive swallowing events as well as imperfect velopharyngeal closure. The most influent parameters are found to be the amount of the residual product in the pharynx and its contact area with the air flux, the volume of the nasal cavity, the equilibrium air/product partition coefficient of the volatile compound, the breath airflow rate, as well as the mass transfer coefficient of the aroma compound in the product, and the amount of product in the mouth. This work constitutes a first step toward computer-aided product formulation by allowing calculation of retronasal aroma intensity as a function of transfer and volatility properties of aroma compounds in food matrices and anatomophysiological characteristics of consumers.     

Green tea aroma fraction reduces β-amyloid peptide-induced toxicity in Caenorhabditis elegans transfected with human β-amyloid minigene

Green tea is a popular world-wide beverage with health benefits that include preventive effects on cancer as well as cardiovascular, liver and Alzheimer’s diseases (AD). This study will examine the preventive effects on AD of a unique aroma of Japanese green tea. First, a transgenic Caenorhabditis elegans (C. elegans) CL4176 expressing human β-amyloid peptide (Aβ) was used as a model of AD. A hexane extract of processed green tea was further fractionated into volatile and non-volatile fractions, named roasty aroma and green tea aroma fractions depending on their aroma, by microscale distillation. Both hexane extract and green tea aroma fraction were found to inhibit Aβ-induced paralysis, while only green tea aroma fraction extended lifespan in CL4176. We also found that green tea aroma fraction has antioxidant activity. This paper indicates that the green tea aroma fraction is an additional component for prevention of AD.     

Production of Shoot-tip Culture Lines of Asakura-sanshoo (Zanthoxylum piperitum DC. f. inerme Makino) with High Aroma Emanation

An analysis of the aroma components of Asakura-sanshoo leaves was conducted by using head-space gas chromatography. It shows that a greater part of the shoot-tip culture lines of Asakura-sanshoo preserved the same characteristics as those of the parent plant with respect to aroma productivity in the secondary metabolites, apart from a few variant strains. It was found, however, that the level of total aroma components of selected variant culture lines gradually increased during five subcultures, although that of the control culture lines remained low. Thus, the combination of shoot-tip culture and selection was found to be very effective for improving Asakura-sanshoo with high aroma emanation.     

不同石斛兰香气成分的GC-MS分析

利用GC/MS技术分析了四种石斛兰Dendrobium Nora Tokunaga、Dendrobium Green Lantern、Dendrobium Spider Lily和Dendrobium Little Green Apples花朵的香气成分.结果表明,四种石斛兰香气成分的种类和含量存在明显差异,其中Den...     

Metabolic engineering of aroma components in fruits

Plants have the ability to produce a diversity of volatile metabolites, which attract pollinators and seed dispersers and strengthen plant defense responses. Selection by plant breeders of traits such as rapid growth and yield leads, in many cases, to the loss of flavor and aroma quality in crops. How the aroma can be improved without affecting other fruit attributes is a major unsolved issue. Significant advances in metabolic engineering directed at improving the set of volatiles that the fruits emit has been aided by the characterization of enzymes involved in the biosynthesis of flavor and aroma compounds in some fruits. However, before this technology can be successfully applied to modulate the production of volatiles in different crops, further basic research is needed on the mechanisms that lead to the production of these compounds in plants. Here we review the biosynthesis and function of volatile compounds in plants, and the attempts that have been made to manipulate fruit aroma biosynthesis by metabolic engineering. In addition, we discuss the possibilities that molecular breeding offers for aroma enhancement and the implications of the latest advances in biotechnological modification of fruit flavor and aroma.     

Impact of swallowing on the dynamics of aroma release and perception during the consumption of alcoholic beverages

The consumption protocol used during alcoholic beverage tasting may affect aroma perception. We used an integrated approach combining sensory analysis and physicochemistry to investigate the impact of swallowing on aroma release and perception. A panel of 10 persons evaluated the dynamics of aroma perception during the consumption of a commercial flavored vodka, using the method of temporal dominance of sensations. Two protocols (spitting out or swallowing of the product) were tested. Nosespace analysis was simultaneously carried out by proton transfer reaction mass spectrometry to evaluate aroma release in the nasal cavity. Comparison of the results obtained with the 2 protocols highlighted significant differences in both the perception and the release of aroma: the swallowing of the product resulted in more complex perceptions but decreased the dominance rates of aromatic attributes. Ethanol perception also had an impact when the product was swallowed. Aroma release data partly accounted for the differences in perception, particularly as concerned ethanol release. The time at which dominance appears as well as the dominance duration of some attributes can be related to some temporal parameters of release data. But the lack of knowledge concerning the variety and complexity of mechanisms continues to limit our understanding of relationship between aroma release and perception.