Aroma characterization of various apricot varieties using headspace–solid phase microextraction combined with gas chromatography–mass spectrometry and gas chromatography–olfactometry

The characterization of the aromatic profile of several apricot cultivars with molecular tracers in order to obtain objective data concerning the aromatic quality of this fruit was undertaken using headspace–solid phase microextraction (HS–SPME). Six apricot cultivars were selected according to their organoleptic characteristics: Iranien, Orangered, Goldrich, Hargrand, Rouge du Roussillon and A4025. The aromatic intensity of these varieties measured by HS–SPME–Olfactometry were defined and classified according to the presence and the intensity of grassy, fruity and apricot like notes. In the six varieties, 23 common volatile compounds were identified by HS–SPME–GC–MS. Finally, 10 compounds, ethyl acetate, hexyl acetate, limonene, β-cyclocitral, γ-decalactone, 6-methyl-5-hepten-2-one, linalool, β-ionone, menthone and (E)-hexen-2-al were recognized by HS–SPME–GC–O as responsible of the aromatic notes involved in apricot aroma and considered as molecular tracers of apricot aromatic quality which could be utilized to discriminate apricot varieties.     

Fruit physical,chemical and aromatic attributes of early,intermediate and late apricot cultivars

BACKGROUND: In order to reach good fruit quality, apricots require a balance of sugars and acids as well as a strong apricot aroma. In this study, fruit quality of early, intermediate and late apricot cultivars was evaluated by measuring physical, chemical and olfactory attributes. Multivariate analysis of quality and aroma attributes was used to identify groups of similar cultivars and association with ripening season. RESULTS: Physical, chemical and aromatic attributes showed great variation among cultivars but no relation to ripening season. Aromatic profiles (34 volatiles) of fruit tissues indicated qualitative and quantitative differences among cultivars. Ninfa and Mandorlon were richest in aroma, with a prevailing fruity component; Goldrich and Orange Red were also highly aromatic, with all odour components well represented; Pinkot, Alba and Pellecchiella were lowest in aroma, with a prevailing grassy component. Linear functions including five volatiles (concentrations) and fruit diameter or six aromatic compounds (odour units) and peel colour were found to discriminate cultivars by ripening season. Principal component analysis individuated three groups of cultivars: Ninfa and Mandorlon with sweet and fruity‐flavoured fruits; Bulida, Alba, Goldrich, Ouardy and Silvercot with large, acidic and well‐coloured fruits; and Fracasso, Pellecchiella, Palummella and Pinkot with small and floral/grassy‐flavoured fruits. CONCLUSION: In apricot, detailed analysis of the aromatic profile may represent an efficient tool for classification of genotypes by ripening season, and volatiles with relevant odour contribution may serve as quality markers for selecting towards an extended ripening season of best quality apricots. Copyright © 2010 Society of Chemical Industry     

Characterization of aroma potential of apricot varieties using different extraction techniques

Aroma compounds are presents in raw foods, freely and glycosidically-bounded (aroma precursors). In the present work, the volatile fraction of eight varieties of apricot were analyzed using simultaneous distillation extraction (SDE), solid phase extraction (SPE) with reverse phase (C18), liquid–liquid extraction (LLE) and headspace-solid phase microextraction (HS-SPME). The free aroma compounds were identified by GC–MS, finding common compounds such as linalool, α-terpineol, β-ionone and γ-decalactone and specific compounds due to the extraction method used. The ANOVA showed a significant effect in the extraction techniques and on the varieties in the free aromatic fraction from apricot as well. In spite of a large number of volatile compounds extracted by SPE, the technique that allowed for the most number of compounds to be extracted was SPME.     

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     

福建省4 个果梅主栽品种果实营养品质、香气成分分析与评价

以福建省4 个果梅主栽品种青竹梅、龙眼梅、杭梅和白粉梅为试材,分析测定果实的主要性状和营养成分,包括单果质量、果实大小、VC、总酚、类黄酮、可溶性糖、有机酸、香气组分以及矿质元素含量。结果表明,4 个果梅品种VC、总酚、类黄酮、可溶性糖、有机酸、香气组分以及矿质元素含量存在显著差异。果梅主要可溶性糖为蔗糖,其次为葡萄糖和果糖;主要有机酸为柠檬酸,其次为苹果酸、琥珀酸、乙酸和奎宁酸;4 个果梅品种果实共检测出110 种挥发性物质,包括30 种酯类、26 种醇类、17 种醛类、15 种酮类、7 种酸类以及15 种其他类,其中有26 种物质为4 个品种共有成分,2-己烯醛、己醛、己醇和反式-罗勒烯醇可能是果梅特征香气的重要物质;4 个果梅品种含有较高的K、Ca和Se含量。通过主成分分析提取,得出综合得分品种最高为青竹梅,青竹梅果实挥发性物质相对总含量高于其他3 个品种且综合品质最佳,适宜作为选育果梅良种的育种材料。本研究结果为明确果梅营养价值评价及其在良种选育、生产加工中的合理利用提供理论依据。     

SPME-GC-MS detection of volatile compounds in apricot varieties

Aroma compounds of the eight Malatya apricot cultivars, six cultivars grown in the same breeding conditions from different locations and one hybrid cultivar were determined using SPME-GC-MS technique. In general, total concentration (sum of identified and unidentified peaks) of aroma compounds in Malatya apricot cultivars were lower than those others. Total concentration of aroma compounds were found to be in the range of 514 and 6232 μg/kg fresh weight. The main volatiles of apricot cultivars were aldehydes, alcohols, acetates, esters, terpenes and acids. Among these compounds; ethanol, hexanal, hexyl acetate, (Z)-3-hexenyl acetate, (E)-2-hexenyl acetate, 1-hexanol, (Z)-3-hexenol and (E)-2-hexen-1-ol, were present in all cultivars studied at certain levels.     

基于ATD-GC-MS技术的不同品种白牡丹茶香气成分分析

采用自动热脱附-气相色谱-质谱联用仪(automatic thermal desorption-gas chromatography-mass spectrometry, ATD-GC-MS)对不同品种牡丹制成的白牡丹茶进行香气检测分析,探究其香气成分特征。结果显示,5个白牡丹品种茶中共鉴定出50种香气成分,正己醛、壬醛、癸醛、苯甲醇、芳樟醇、1-戊醇和β-紫罗兰酮是主要香气成分,奠定了白茶的香气基础。有44种组分的香气成分含量,经单因素分析达到显著差异水平(P<0.05),且香气活性值(odor activity value, OAV)在不同品种白牡丹茶间也存在差异,其中,政和大白茶含有较高的醛类和醇类化合物,福鼎大毫茶含有较为丰富的醇类化合物,福云6号含有较高的醛类和碳氢化合物,九龙大白茶和福云595含有较高的醇类和碳氢化合物。本研究可为进一步探究白茶品种香型特征划分提供参考依据。     

杏汁发酵与杏皮渣发酵对杏酒香气质量的影响

为优化杏酒的发酵工艺,提高杏果的综合利用价值,减少资源浪费和环境污染,以杏汁和杏皮渣为原料,分别加入两种酵母进行发酵,比较发酵工艺对杏酒基本理化指标、香气物质和感官特性的影响。采用4 种发酵工艺,工艺1为杏汁＋酵母BV818,工艺2为杏汁＋酵母CECA,工艺3为杏皮渣＋酵母BV818,工艺4为杏皮渣＋酵母CECA。用气相色谱-质谱测定杏酒中的香气物质,并对杏酒进行感官评价。在杏酒中共检测出41 种香气物质,包括酯类29 种、醇类5 种、醛类2 种和萜烯类5 种,其中酯类物质种类最多,且含量最高,占香气总量的72.7%。在工艺1～4的酒样中,香气总量分别为14 765.27、15 034.37、12 580.27 μg/L和7 347.61 μg/L,用杏汁发酵的杏酒中香气总量显著高于用杏皮渣发酵的杏酒。在4 种工艺酒样中均能检出且气味活性值大于1的香气物质为杏酒的特征香气物质,共有6 个,分别为辛酸乙酯、己酸乙酯、乙酸异戊酯、芳樟醇、癸酸乙酯和丁酸乙酯。主成分分析结果显示,工艺2的酒样与乙酸异戊酯、丁酸乙酯、己酸乙酯、辛酸乙酯和芳樟醇5 种特征香气物质处于同一象限,说明该酒样具有杏酒的典型香气特征。感官评价结果显示,杏酒具有杏、桃、柑橘、苹果、梨等果香和槐花、金银花等花香,采用工艺2酿造的杏酒,感官评分最高。结论：用杏汁发酵的杏酒,香气物质含量较高,以果香和花香为主,酒体轻盈,口感清爽,而用杏皮渣发酵的杏酒,总酚含量较高,香气复杂,酵母味明显,酒体饱满。本研究为杏酒发酵工艺的优化提供技术支持,也为进一步研究杏酒香气物质的合成提供理论依据。     

杏汁挥发性成分分析及在卷烟加香中的应用

采用固相微萃取法提取杏汁中的挥发性香气物质,经气相色谱-质谱联用仪对提取物进行挥发性成分的分离和鉴定,确认了其中的60种成分,占总质量分数的92.08%,主要香气成分为酸类(32.60%)、醇类(18.45%)、醛类(18.10%)、酯类(13.95%)、酮类(2.84%)等.卷烟加香实验表明:杏汁提取物能赋予卷烟甜香、果香,提高卷烟香气的柔和性和圆润性,降低刺激性,掩盖杂气,改善口感,起到明显提升卷烟品质的作用;对不同的烟丝施加量应略有区别,一般控制在0.05%～0.1%范围内效果较佳.     

Volatile profiles of aromatic and non-aromatic rice cultivars using SPME/GC–MS

Rice (Oryza sativa L.) is enjoyed by many people as a staple food because of its flavour and texture. Some cultivars, like scented rice, are preferred over others due to their distinctive aroma and flavour. The volatile profile of rice has been explored by other investigators, some of whom have also determined a corresponding aroma using GC/olfactometry. However, little research has been done to determine if different aromatic rice cultivars produce different flavour volatiles that would make them more desirable than others when cooked. In this study, seven aromatic and two non-aromatic cultivars were examined for their volatile profiles both before and after storage using solid phase microextraction (SPME) fibres in conjunction with gas chromatography/mass spectrometer (GC–MS). Ninety-three volatile compounds were identified, 64 of which had not been previously reported in rice. Differences were found in the volatile compounds of aromatic and non-aromatic rice besides 2-acetyl-1-pyrroline (2-AP). Most of the volatile compounds were present in freshly harvested rice and rice following storage, with very few new compounds being identified only after storage. Dellrose, an aromatic cultivar, and Cocodrie, a non-aromatic cultivar, had the most complex volatile profiles (over 64 volatiles). Sixteen compounds were found only in the aromatic cultivars, and some volatiles were found to be unique to specific aromatic cultivars. However, no distinctive pattern was observed that would identify a cultivar as being derived from Basmati, Khao Dawk Mali 105 (i.e. jasmine), or other sources of aroma. This study showed that there is a great diversity of volatiles in both aromatic and non-aromatic rice cultivars and, with further research, this may lead to a better understanding of the combination of compounds that gives a cultivar a unique flavour.     

Quantification of Some Volatile Aromatic Compounds of Apricot by Adding Standards

The quantification of twelve volatile aromatic compounds of apricot was realized by adding known amounts of pure compounds directly in the slurry before analysis by vacuum distillation and gas chromatography. This method was compared with the classical technique using an internal standard and was applied to two different apricot cultivars. Large differences were observed between the amounts of volatiles calculated by the two methods. They are due to the differences between the extraction coefficients of the quantified compounds and to the retentions of volatiles on nonvolatile compounds, which may vary according to the polarity.     

早熟梨果实不同成熟阶段的香气组成

以早熟梨--翠冠、爱甘水、中梨1号为材料,用顶空固相微萃取结合气质联用技术对果实不同成熟阶段的香气组成和含量进行研究。结果表明：3个早熟梨品种不同成熟阶段的果实中醛、醇、酯、酮和烯烃类物质均有检出,但主要香气成分是己醛、2-己烯醛、壬醛、1-己醇和3-己烯-1-醇等醛和醇类物质;果实发育成熟过程中,随着成熟度增加,各品种的香气物质总量均有增加,但各香气成分间存在差异,醛的含量随成熟度的提高而增加,醇的含量除翠冠外均有减少;果实成熟早期爱甘水的香气物质含量最高,成熟后期翠冠的香气物质含量最高,约为其他两品种的2倍。各品种在不同成熟阶段的香气组成和含量表现出各自不同的特点。     

Development of Volatile Compounds during Fruit Maturation: Characterization of Apricot and Plum×Apricot Hybrids

Optimum fruit quality depends upon a number of factors, including fruit developmental stage at harvest. The volatile constituents present in apricot fruit and plumcot accession P251-002 during three different developmental stages have been studied, as well as some physical characteristics such as weight, firmness, °Brix, titratable acidity and flesh and skin colour. The volatile compounds behaved differently during the fruit maturation period, alcohols being the most important group, quantitatively, during the three developmental stages in apricot fruit. In plumcot, total volatiles obtained from fruit sample extractions were very similar in each developmental stage; however, the aromatic profile of constituents changed as fruit maturity progressed to a tree ripe stage. Important differences were found in the volatile constituents profile for both fruits; at the tree ripe stage, the concentration of lactones and terpenic alcohols, characteristic compounds of apricot aroma, were much higher in apricot than plumcot, the latter more resembling a plum aromatic profile. Even with the important presence of lactones that gives a very aromatic apricot when tree ripe, the low firmness at this point does not allow any commercial use of the fruit. © 1997 SCI     

Characterization of aromatic properties of old-style cheese starters

Old-style cheese starters were evaluated to determine their ability to produce cheese aroma compounds. Detailed analyses of the aroma-producing potential of 13 old-style starter cultures were undertaken. The proteolytic profile of the starters was established by an accelerated ripening study using a model cheese slurry and compared with those of a commercial aromatic starter and commercial Cheddar cheeses. To evaluate the aromatic potential of the starter cultures, quantification of free amino acids liberated and volatile compounds after 15 d of ripening at 30°C as well as sensory analysis were carried out. Results showed that proteolysis patterns of all 13 starter cultures in the curd model were comparable to those of commercial Cheddar cheeses. All tested cultures demonstrated the ability to produce high amounts of amino acids recognized as precursors of aroma compounds. Several differences were observed between the starters and commercial Cheddar cheeses regarding some amino acids such as glutamate, leucine, phenylalanine, proline, and ornithine, reflecting the various enzymatic systems present in the starters. Starters Bt (control) and ULAAC-E exhibited various significant differences regarding their free amino acid profiles, as confirmed by sensory analysis. In addition, identification of volatile compounds confirmed the presence of several key molecules related to aroma, such as 3-methylbutanal and diacetyl. Besides the aroma-producing aspect, 2 starters (ULAAC-A and ULAAC-H) seem to possess an important ability to generate large amounts of γ-aminobutyric acid, which contributed up to 15% of the total amino acids present in the model curd after 15 d ripening. γ-Aminobutyric acid is an amine well-known for its antihypertensive and calming effects.     

锦橙和宫川果汁香气成分比较研究

采用同时蒸馏提取法(SDE)制备样品,GC-MS联机分析,计算机谱图库检索定性,对锦橙和宫川蜜柑果汁的香气成分进行了鉴定,共检测出73种香气化合物。酯类、醇类、醛类、烯类和酮类物质是其主要香气成分,其中锦橙果汁中检出香气成分62种,宫川蜜柑果汁中检出香气成分32种。锦橙和宫川蜜柑果汁香气成分的种类和含量差别明显,因此在柑橘果汁的生产过程中,可以考虑按照一定的比例做适度的搭配,以生产出更优质的柑橘果汁。     

Trehalose improves flavour retention in dehydrated apricot puree

The influence of the addition of two sugars (trehalose and sucrose) on the retention of volatiles responsible for the characteristic aroma in dehydrated apricot puree was studied. Aroma compounds of fresh and both freeze‐dried and foam‐mat‐dried apricot puree were analysed by manual headspace solid‐phase microextraction coupled with gas chromatography (GC‐FID and GC‐MS). The best retention of aroma compounds in dehydrated apricot puree was obtained when trehalose was added, regardless of the dehydration process used (freeze drying or foam‐mat drying), although, generally, a much higher retention of flavour volatiles was obtained in freeze‐dried purees. Principal Component Analysis and Cluster Analysis were applied to all the apricot purees studied to obtain a simplified view of the relationship among the aroma compounds in dehydrated apricot purees. This study gives further insights into the mechanisms that occur when trehalose is applied as an additive and will enable the development of new processes to maximize this effect and to produce superior dried products.     

六个早熟鲜食葡萄品种果实香气成分分析

以亲本‘葡萄园皇后’‘红香蕉’和子代‘丰宝’‘红双味’‘贵妃玫瑰’‘黑香蕉’6个早熟鲜食葡萄品种为试材,采用顶空固相微萃取结合气质联用技术对其果实的香气成分进行分析测定,调查各品种成熟果实的芳香物质差异。结果表明,成熟果实中C6化合物含量高,是贡献最大的挥发性化合物,其中相对含量最高的是具有青草、草本香气的2-己烯醛和己醛;烯烃类、酯类是构成不同品种葡萄特征香气的重要组成,其中反式-β-紫罗兰酮、里那醇、香茅醇等具有玫瑰花香的化合物的气味活性值高,对‘贵妃玫瑰’‘葡萄园皇后’贡献较大;具有果香、香蕉香气的己酸乙酯、辛酸乙酯、丁酸乙酯的气味活性值高对‘红香蕉’‘黑香蕉’的贡献突出。     

HPLC-DAD-MS characterisation of carotenoids from apricots and pumpkins for the evaluation of fruit product authenticity

Carotenoids including carotenoid esters from six apricot (Prunus armeniaca L.) cultivars and from eight cultivars from three pumpkin species (Cucurbita maxima Duch., Cucurbita pepo L., and Cucurbita moschata Duch.) were extracted without saponification, separated on a C-30 reversed-phase column and characterised by high-performance liquid chromatography/atmospheric pressure chemical ionisation–mass spectrometry (LC–MS). The predominant free carotenoids were quantified by HPLC with diode array detection. In contrast to previously published data, α-carotene could not be detected in apricots. Although the pumpkins showed significant differences in their free carotenoid profiles, major unesterified compounds different from those found in apricots could be determined. However, due to the natural heterogeneity, authentication of the apricot products cannot be accomplished exclusively using the profile of free carotenoids. Therefore, the investigations were extended to carotenoid esters. The xanthophyll ester profiles in pumpkins significantly differed from those in apricots in that the latter also contained both saturated and unsaturated fatty acids, whereas in pumpkins exclusively saturated fatty acids were detected. Admixtures of lower cost pumpkins could be detected in quantities of ?5% by increased contents of lutein and zeaxanthin, and by the appearance of antheraxanthin and α-carotene, respectively, depending on the added pumpkin cultivar, as well as the presence of characteristic lutein and antheraxanthin esters. However, pronounced differences in the carotenoid profiles of the investigated pumpkins and the partly minor amount of characteristic compounds lead to limitations of the detection of 5% level of admixture of pumpkin to apricot and of the method in general.     

Volatile flavour substances of apricot and their changes during ripening

Aroma content and composition of different Hungarian and foreign apricot cultivars were studied. Volatile flavour substances were isolated by simultaneous steam distillation-extraction. GC and GC/MS analysis of the aroma extracts revealed 40 components, 12 of them have been reported for the first time in apricots. The changes in the aroma composition of the cultivar “Hungarian kajszi” during ripening were also studied.