基于多元分析的11种烟台中、晚熟品种苹果香气成分比较

为了探明烟台中、晚熟苹果品种间主要香气成分的差异,采用顶空固相微萃取(HS-SPME)结合气相色谱与质谱联用(GC-MS)对11种烟台中、晚熟品种苹果的香气成分进行检测分析,并对不同品种的苹果以及其香气成分的种类进行主成分分析和聚类分析。结果表明,从11种苹果中共检测出59种香气成分,其中21种成分为所有品种苹果所共有,在共有香气成分中,乙酸、丁酸、己酸的酯类化合物,己醛(包括2-己烯醛)与一些高级醇含量较高。主成分分析表明,阳光苹果、丹霞苹果综合得分较高,极早熟富士苹果综合得分最低,得分排名反映出苹果品种之间主要香气成分的差异大小。聚类分析表明,11种苹果可分为四类:第一类为烟富三、斗南、甘红、极早熟富士、皮诺娃、烟富一、最良短富;第二类为丹霞、阳光;凉香和华帅分别自为一类。经过两种分析方法有效结合,筛选得到的丹霞、阳光、凉香、华帅四种苹果香型特点更为突出,为今后品质育种亲本选择提供依据。     

Cultivar discrimination of stored apple seeds based on geometric features determined using image analysis

Digital image analysis can allow determining the features of seeds and their interpretation in a fast, inexpensive, and non-destructive way. The research aimed to develop discriminative models based on geometric features to distinguish seeds belonging to different apple cultivars. Images of seeds of apples ‘Gala’, ‘Jonagold’ and ‘Idared’ were acquired using a flatbed scanner. The linear dimensions and shape factors were calculated, and after attribute selection, they were used for the discriminant analyzes of seeds for ‘Gala’ with ‘Idared’, ‘Gala’ with ‘Jonagold’, ‘Idared’ with ‘Jonagold’ and ‘Gala’ with ‘Idared’ with ‘Jonagold’ with the use of discriminative classifiers from Bayes, Function, Meta, Rules and Decision Trees groups. In the case of models build based on selected linear dimensions, the accuracy of discrimination was equal up to 84% for distinguishing seeds of all three apple cultivars for the J48 classifier from Decision Trees and 93% for analysis of ‘Gala’ and ‘Idared’ for the J48 from Decision Trees. The slightly lower correctness of up to 82% for discrimination of ‘Gala’, ‘Idared’ and ‘Jonagold’, Multi Class Classifier) and 90% (‘Gala’ and ‘Jonagold’, J48) were obtained for models build based on selected shape factors. The analyzes performed based on sets including selected combined linear dimensions and shape factors of seeds provided the correctness of up to 86% for the discrimination of three apple seed cultivars (J48) and 91% (‘Gala’ and ‘Jonagold’, J48). The results can be used in practice for the assessment of the authentication of seeds of apple cultivars with high probability.     

Phenolic compounds in some apple (Malus domestica Borkh) cultivars of organic and integrated production

Eleven organically grown apple cultivars and 11 apple cultivars of integrated production from Austria and Slovenia were analyzed by HPLC for the content of phenolic compounds in peel and pulp. We identified chlorogenic acid, p‐coumaric acid, procyanidin B3, protocatechuic acid, (?)‐epicatechin, phloridzin, rutin and quercetin‐3‐rhamnoside in apple peel. In apple pulp, (+)‐catechin was also identified in all the cultivars. Some other phenols (procyanidin B3, rutin and quercetin‐3‐rhamnoside) could not be identified or were not properly separated. With regard to the phenolic content in the apple peel, there were no differences between organically grown apple cultivars and apple cultivars of integrated production. Organically grown apples, however, exhibited a higher content of phenolic substances in the apple pulp compared with the apple cultivars of integrated production. This may be due either to the different genotype source or to the growing technology. Higher concentrations of phenolic compounds in organically grown cultivars could be a result of plant response to stress. The apple peel contained higher concentrations of identified phenols than the pulp. The apple peel represents up to 10% of the whole fruit; therefore the phenolsic compounds in the pulp are of greater importance to the consumer than the phenolic compounds in the peel. Copyright © 2005 Society of Chemical Industry     

Changes of contents and antioxidant activities of polyphenols during fruit development of four apple cultivars

Polyphenols are functional components in apples and can be separated into four groups by Sephadex LH-20 as epicatechin, procyanidolic oligomers, chlorogenic acid and procyanidolic polymers. Antioxidant activities of each group were determined by FRAP and DPPH radical scavenging assay. It was found that procyanidolic oligomers and procyanidolic polymers influenced the total polyphenols content (measured by Folin–Ciocalteu method) much more in Jonagold, Golden Delicious, Fuji and Guoguang four apple cultivars. The Fe-reducing activity of procyanidolic oligomers in the four apple cultivars increased significantly during the development while the other three compounds changed irregularly. And the Fe-reducing activities of epicatechin and procyanidin contributed much more to the total Fe-reducing activities during the fruit development in the four apple cultivars. The DPPH scavenging activities of four compounds in Jonagold and Golden Delicious decreased during fruit development and that of Fuji and Guoguang changed irregularly. Chlorogenic acid was the main contributor in Jonagold, Golden Delicious and Fuji to the total scavenging activity. In Guoguang, it was procyanidolic oligomers that contributed much to the total scavenging activity.     

A comparison of the flavonol content and composition in dessert,cooking and cider-making apples; distribution within the fruit and effect of juicing

The fruit of all apple varieties tested possessed five quercetin glycosides, namely hyperin, isoquercitrin, reynoutrin, avicularin and quercitrin, as the major flavonol components. Total flavonol levels were in the range 26.4 to 73.9μg/g fresh wt (expressed as aglycone) with hyperin the dominant form in all varieties except Egremont and Jonagored, where quercitrin predominated, and the cider apples, where avicularin predominated. The proportion of flavonol in the peel ranged from 63.0 to 97.1% for the dessert and cooking apples and was not dependent on fruit size. Juice produced from the three varieties of cider apple contained 9.9 to 12.7% of the flavonols with the remainder retained in the pomace.     

Character impact odorants of the apple cultivars Elstar and Cox Orange

Extracts obtained from Elstar and Cox-Orange apples (Malus var. domestica Borkh.) were screened for potent odorants by aroma extract dilution analysis (AEDA). (E)-beta-Damascenone (I), (E)-beta-damascone (II), hexanal (III), (Z)-3-hexenal (IV), (Z)-2-nonenal (V), linalool (VI), butyl acetate (VII), 2-methylbutyl acetate (VIII) and hexyl acetate (IX) were identified in Elstar and I, III-V, ethyl butanoate (X), ethyl 2-methylbutanoate (XI), 1-octen-3-one (XII), (E)-2-octenal (XIII), methional (XIV), (E)-2-nonenal (XV), eugenol (XVI) and wine lactone (XVII) in Cox Orange. The release of odorants by the cultivars was analysed by gas chromatography-olfactometry of headspace samples. Esters X and XI showed the highest odour activities in the air above Elstar apples and ester X, acetaldehyde (XVIII), 2-methylbutanol (XIX) and ethyl methylpropanoate (XX) in that of Cox Orange. Preparation of a homogenate changed the headspace composition of potent odorants. Hexyl acetate (IX) became the key odorant of Elstar and aldehydes III and IV those of Cox Orange. Quantification and calculation of odour activity values indicated I, IV, V, VII, VIII and IX as the character impact odorants of the fruit flesh of the two cultivars. Elstar contained more I, V, VII and IX and Cox Orange more IV than the other cultivar. The concentrations of VIII were similar.     

Bioactive phytochemicals in apple cultivars from the Portuguese protected geographical indication “Maçã de Alcobaça:” Basis for market segmentation

Phytochemical composition and antioxidant activity of eight apple (Malus domestica) cultivars (“Casa Nova,” “Fuji,” “Golden Delicious,” “Granny Smith,” “Jonagored,” “Reinette Grise,” “Royal Gala,” and “Starking”) from the “Maçã de Alcobaça” protected geographic indication, Portugal, were characterized to support market segmentation based on phytochemical content. Total phenolics, flavonoids, and anthocyanin contents, individual polyphenols and antioxidant activity were assessed in the flesh and skin of fruit at the ripe stage. A market segmentation of apple cultivars based on these bioactive phytochemicals is proposed. Fruit eaten with the peel can be segmented in three classes: (1) the flavonoid-rich “Starking,” “Reineta,” “Galaxy,” “Casa Nova,” Jonagored;” (2) the quercetin-rich “Fuji,” “Galaxy,” “Casa Nova;” and (3) flavonol and procyanidin-rich “Starking,” “Reinette,” “Jonagored,” “Casa Nova.” When apples were peeled before consumption, two phytochemical classes were proposed: (1) the flavonoid-rich “Reinette” and “Casa Nova,” and the (2) chlorogenic acid-rich “Reineta,” “Casa Nova,” and “Starking.”     

新疆地区与黄河流域红富士苹果性状与品质分析

精选新疆地区、黄河流域16种红富士苹果,进行果实性状、营养成分分析和感官评价:新疆阿克苏、伊犁特克斯和陕西洛川的红富士苹果表现最佳。4地红富士苹果平均单果重甘肃陕西新疆山东,种群内变异性大(CV15%),具有显著性差异(p=00.05)。16种红富士苹果种群内部营养成分变异性较大(CV10%),尤其Vc、蛋白、膳食纤维(CV25%);不同产地间红富士还原糖(p=00.05)、可溶性固形物(p=0.05)、膳食纤维(p=0.0230.05)具有显著性差异。风味评分与固酸比之间具有显著正相关关系(p=00.05,r=0.886),新疆红富士具有更高的固酸比,且与其它地区具有显著性差异(p=0.0090.05),使得新疆红富士苹果更能满足人们对于风味的较高要求且与其它地区具有显著性差异(p=0.0030.05)。此外,还原糖与可溶性固形物具有显著正相关关系(p=0.0010.05,r=0.75),总酸和可溶性固形物之间存在显著正相关关系(p=0.0140.05,r=0.602)。     

X‐Ray Micro‐Computer Tomographic Method to Visualize the Microstructure of Different Apple Cultivars

Apples are appreciated for their texture with firmness acting as an indicator of quality. During prolonged storage, apples can soften and their texture can become undesirably mealy. Using an X‐ray microcomputer tomography (μ‐CT) scanner, the porosity (ratio of intercellular space [IS] to total volume) and the structural arrangement of the parenchyma tissue of 4 apple cultivars (Braeburn, Fuji, Golden Delicious, Jazz) stored under similar conditions for 100 d were visualized via the development of 2D and 3D images. The texture of the apples was also measured using a puncture test. The morphometric and textural measurements revealed that firm Jazz apples (flesh firmness: 29.84N) had a lower porosity (17%) compared to soft Golden Delicious apples (flesh firmness: 14.16N; porosity: 29.8%). In general, firm apples had a higher dry matter (%) and a lower porosity (%), while the reverse was true for softer apples. However, this was not an absolute trend as cultivar specific differences in the microstructural organization and consequent mechanical strength of the parenchyma tissue also influenced firmness. For example, although Fuji apples were firm (28.42N), they had a high porosity (29.3%) due to the presence of numerous small and compact IS. In comparison, soft Golden Delicious apples had a high porosity (29.8%) due to the presence of large, interconnected IS. Imaging technologies have the potential to provide a pictorial or graphical database showing the size range distribution of IS corresponding to different parenchyma tissue types and how they relate to apple texture and eating quality.     

DEVELOPMENT OF A PHOTOGRAPHIC SCALE FOR THE VISUAL EVALUATION OF APPLE STRIPE DENSITY1

This research developed a photographic scale for the evaluation of stripe density for 5 apple cultivars (Carousel, 8M-15-10, Fuji, Gala, and Jonagold) using a series of two experiments. In Experiment 1, subjects were able to significantly discriminate and reproducibly score the stripe density of apples using unstructured graphic line scales. Photographs of selected apples were then labelled with the corresponding mean scores and used as visual references for Experiment 2. In Experiment 2, subjects reproducibly evaluated the stripe density of apples using structured line scales (anchored with 3 or 5 photographic references), with similar mean scores from the 3- or 5-point scales. Subject differed very little in their variances reflecting the potential usefulness of these line scales for commercial evaluation of apple stripe density in whole apples.     

‘新红星’和‘长富2号’果实贮藏期间香气成分的变化

采用顶空固相微萃取技术和气相色谱-质谱联用研究‘新红星’和‘长富2号’苹果果实不同贮藏期间香气成分的组成及含量变化。结果表明:‘新红星’和‘长富2号’成熟果实中分别检测出50、49种挥发性成分,共有的香气成分38种,其中30种为酯类物质,乙酸酯类物质相对含量分别占香气物质总量的70.81%和52.60%,对成熟期苹果果实香气的形成发挥重要作用。常温(15~25℃)贮藏过程中,‘新红星’和‘长富2号’果实中酯类物质含量呈先升后降的趋势,贮藏20 d时达到最高值,分别占2个品种香气物质总量的97.94%和95.83%。贮藏期间乙酯类物质相对含量明显增加,其中丁酸乙酯、2-甲基丁酸乙酯、丙酸乙酯、乙酸乙酯、己酸乙酯等上升幅度较大,对‘新红星’和‘长富2号’苹果贮藏期间特有香气的形成起重要作用。     

4-methoxyallylbenzene: An important aroma component of apples

Headspace collection techniques on whole apples, coupled with sensory evaluation, gas chromatography, gas chromatography-mass spectrometry and infrared spectroscopy has enabled 4-methoxyallylbenzene to be identified as a component contributing to the important spice-like note in the aroma of a number of apple cultivars. This compound is present in varying amounts in all those examined but is more prominent in Ellison 's Orange, where it gives a recognisable aniseed-like character to the aroma.     

Causal Effects of Aroma Compounds on Royal Gala Apple Flavours

Volatile flavour compounds produced by Royal Gala apple have been identified by GC-MS. Major components were 2-methylbutyl acetate, butyl acetate, hexyl acetate, butanol, 2-methylbutanol and hexanol. Odour-port evaluation of the components separated by GC indicated that the first four compounds were important contributors to the aroma and flavour. Use of analytical sensory panels revealed that 2-methylbutyl acetate, butanol and hexyl acetate had the greatest causal effect on those aroma and flavour attributes considered important for Royal Gala apples.     

基于主成分分析和聚类分析的苹果香气成分比较及品种分类研究

为了探明选用的14种苹果间主要香气成分的差异,采用顶空固相微萃取(HS-SPME)结合气相色谱与质谱联用(GC-MS)对14种苹果的香气成分进行检测分析,并对检测结果进行主成分分析与聚类分析。结果表明,本实验共检测出73种香气成分,其中8种成分为所有品种苹果所共有,分别是乙酸己酯、己酸己酯、2-甲基-1-丁醇、1-己醇、1-辛醇、己醛、反式-2-己烯醛、α-法呢稀。主成分分析表明,寒富和昌红苹果综合得分较高,秦冠和秋锦苹果综合得分最低,该排名可以直观的反映出苹果间差异。聚类分析表明,14种苹果可分为四类:第一类聚集了11个品种,即山东富士、王林、新疆冰糖心富士、寒富、小国光、华富、秦冠、甘肃富士、乔纳金、河北富士。第二类聚集了2个品种,即新红星和国光。秋锦和昌红自成一类。将两种分析方法结合,筛选得到的不同产地富士、王林、昌红和寒富四种苹果香型特点更为突出,为育种者和消费者优选苹果提供理论基础和参考。     

Impact of shelf life on content of primary and secondary metabolites in apple (Malus domestica Borkh.)

In this study, we evaluated the changes in apple fruit quality during shelf life. After a month of cold storage, apples of cultivars "Jonagold" and "Golden Delicious" were exposed to ambient temperatures for 21 d, with subsequent sampling every 3 or 4 d. Fruit firmness, changes in amounts of sugars, malic acid, and phenolics were observed during shelf life. Chemical analyses were done with HPLC-PDA system. An interchange between various sugars was noticed, but in general, the sum of sugars remained at the same level. The content of malic acid remained stable or dropped, resulting in sweeter fruit. Levels of phenolics were more constant in the pulp of both cultivars analyzed, while in the peel, the changes were more pronounced. In the pulp, a peak in the content of hydroxycinnamic acids and flavanols was noticed on the 2nd or 3rd sampling and afterwards, the amounts remained constant. In the peel an initial decrease of all analyzed phenolic groups was observed in both cultivars, however it was more pronounced in "Jonagold." It can be concluded that changes in primary and secondary metabolites are not the main reason for the lower quality of fruit exposed to ambient temperatures. On the other hand, fruit firmness might be the limiting factor for shelf life duration.     

采用主成分分析法对六个苹果品种果实香气分析及分类

全面分析六个苹果品种果实香气成分特点和主要差异。采用顶空固相微萃取结合气质联用检测香气成分。确定了六个苹果品种特征香气成分,采用主成分分析法确定出乙酸己酯、2-甲基丁酸己酯、乙酸丁酯、乙酸异戊酯、己酸己酯和己醛是苹果香型分类的重要判定变量,将六个苹果品种香气分为三类。各品种均以醛类青香气为主,第一类"醛类浓青香型",酸王香气浓度很高,是其它品种约2～4倍,属于此类;第二类"醛类淡青香型",香气成分比较单纯且含量低,澳洲青苹、国光、瑞丹和瑞林属于此类;第三类"青香蕉香型",酯类香蕉香气化合物含量较高,青香蕉属于此类。     

PTR-ToF-MS, A Novel, Rapid, High Sensitivity and Non-Invasive Tool to Monitor Volatile Compound Release During Fruit Post-Harvest Storage: The Case Study of Apple Ripening

In the present study, the potential of PTR-ToF-MS for addressing fundamental and technical post-harvest issues was tested on the non-destructive and rapid monitoring of volatile compound evolution in three apple cultivars (‘Golden Delicious’, ‘Braeburn’ and ‘Gold Rush’) during 25 days of post-harvest shelf life ripening. There were more than 800 peaks in the PTR-ToF-MS spectra of apple headspace and many of them were associated with relevant compounds. Besides the ion produced upon proton transfer, we used the ion at mass 28.031 (C₂H ₄ ⁺ ) produced by charge transfer from residual O ₂ ⁺ as a monitor for ethylene concentration. ‘Golden Delicious’ apples were characterised by higher ethylene emission rates than ‘Gold Rush’ and ‘Braeburn’, and quantitative comparison has been supported by two segment piecewise linear model fitting. Ester evolution during post-harvest ripening is strongly dependent on endogenous ethylene concentration levels. For ‘Golden Delicious’ and ‘Braeburn’, sesquiterpenes (alpha-farnesene) exhibited a fast response to ethylene emission followed by a rapid decline after the endogenous ethylene maximum peak. Carbonyl compounds displayed a different time evolution as compared to esters and terpenes and did not show any evident relationship with ethylene. Methanol and ethanol concentrations during the entire storage period did not change significantly. We show how multivariate analysis can efficiently handle the large datasets produced by PTR-ToF-MS and that the outcomes obtained are in agreement with the literature. The different volatile compounds could be simultaneously monitored with high time resolution, providing advantages over the more established techniques for the investigation of VOC dynamics in fruit post-harvest storage trials.     

Phenolic compounds and fatty acid composition of organic and conventional grown pecan kernels

BACKGROUND: In this study, differences in contents of phenolic compounds and fatty acids in pecan kernels of organically versus conventionally grown pecan cultivars (Cheyenne, Desirable, and Wichita) were evaluated. RESULTS: Although nine phenolic compounds (gallic acid, catechol, catechin, epicatechin, m‐coumaric acid, chlorogenic acid, ellagic acid, caffeic acid and an ellagic acid derivative) were identified in the methanol extract (80% methanol) of defatted kernels, only three compounds (gallic acid, catechin and ellagic acid) existed in sufficient amounts to accurately quantify levels in different cultivars and to study differences in organic versus conventional cultivation. Levels of ellagic acid and catechin found in organically grown ‘Desirable’ were fourfold and twofold higher than in conventional samples, respectively. Furthermore, significant differences in these two compounds were also observed when comparing values between cultivars. Oil content was also significantly greater only in organically grown ‘Desirable’. Oleic acid was the major fatty acid present and its content was significantly higher in organically versus conventionally grown ‘Desirable’ pecans, while there was no difference in levels of oleic acid in ‘Wichita’ and ‘Cheyenne’. On the other hand, linoleic acid content was significantly less in organically versus conventionally grown ‘Desirable’ pecans. CONCLUSION: Overall, these results showed that the effects of cultural differences (i.e. organic versus conventional cultivation) on kernel composition largely depend on the type of pecan cultivar. Copyright © 2009 Society of Chemical Industry