Methyl jasmonate in conjunction with ethanol treatment increases antioxidant capacity,volatile compounds and postharvest life of strawberry fruit

The antioxidant capacity, total anthocyanins, total phenolics, volatile compounds, and postharvest quality of strawberry fruit were evaluated after treatment with natural antimicrobial compounds and during storage at 7.5 °C. Strawberries treated with methyl jasmonate (MJ) in conjunction with ethanol (MJ-ETOH) showed higher antioxidant capacity, total phenolics, and anthocyanins than those treated with ethanol or control (non-treated). MJ-ETOH and ethanol treatments also increased volatile compounds during storage period. However, individual volatile compounds were affected differently. Methyl acetate, isoamyl acetate, ethyl hexanoate, butyl acetate, and hexyl acetate increased, while ethyl butanoate, 3-hexenyl acetate, and methyl hexanoate decreased during storage. The postharvest life was longer for those berries treated with MJ-ETOH and MJ than for those treated with ethanol or control fruit. In conclusion, strawberries treated with MJ-ETOH maintained an acceptable overall quality for the longest storage duration and retained higher levels of volatile compounds; also, berries treated with MJ showed the highest antioxidant capacity compared with other treatments during the postharvest period.     

Evolution of aroma compounds of murtilla fruits (Ugni molinae Turcz) during storage

BACKGROUND: ‘Murtilla’, ‘mutilla’ or ‘murta’ (Ugni molinae Turcz) is a native Chilean species that produces a small berry fruit with a special aroma, whose volatile compounds have not yet been identified. The fruit may be consumed raw and also as jams, juice, canned products, confections and liquor. RESULTS: At the beginning and end of the storage, 24 volatile compounds were identified in murtilla fruit aroma and the concentration of these compounds in murtilla fruit ranged from 1.2 to 250.5 µg kg^?1 fresh weight. Methyl 2‐methyl butanoate, ethyl butanoate, ethyl 2‐methyl butanoate, methyl hexanoate, ethyl hexanoate, methyl benzoate and ethyl benzoate were the major components, all of which have been reported as potent odors in other aromatic fruits. Based on estimated odor activity value, the most potent compound in the murtilla fruit aroma were ethyl hexanoate and 4‐methoxy‐2,5‐dimethyl‐furan‐3‐one. The statistical analysis showed that the storage produced a distinct effect on the same volatile compounds released from the murtilla ecotypes. CONCLUSION: The volatile compounds identified in murtilla fruit aroma, which may be described as fruity, sweet and floral, have been found in other aromatic fruits. Concerning the aroma, the murtilla fruit from ecotype 19‐1 was shown to be the best in cooled storage. Copyright © 2007 Society of Chemical Industry     

Effect of (−)- and (+)-methyl jasmonate on the bioformation of aroma-active esters in strawberry fruits

The effect of (−)- and (+)-methyl jasmonate on the bioformation of selected volatile esters in strawberry was evaluated. To that end, post-harvest treatments of strawberry fruits with (−)- and (+)-methyl jasmonate vapors were accomplished. The selected esters were ethyl 2-methyl butanoate, isoamyl acetate, ethyl hexanoate and hexyl acetate. The results obtained were compared with those provided by the treatment of strawberries with the commercial racemic mixture, i.e., (−/+)-methyl jasmonate. In addition, untreated samples were analyzed to be used as a control. Although the target esters were differently affected by the three treatments depending on the ester considered, a general trend could be observed. The levels of ethyl 2-methyl butanoate and isoamyl acetate decreased significantly with respect to the control sample with both (−)-methyl jasmonate and (+)-methyl jasmonate treatments. However, the variation in the concentrations of ethyl hexanoate and hexyl acetate depended on whether the (−)- or the (+)-enantiomer of methyl jasmonate was used in the treatment. These results reflect different activity of both methyl jasmonate enantiomers on the enzymes regulating strawberry ester biosynthesis. The application of methyl jasmonate enantiomers is here proposed as a possible mean to minimize strawberry aroma alterations and/or losses during post-harvest and storage.     

不同品种草莓的特征香气成分

以"宝交""大将军"和"红宝石"3个品种的草莓为试材,采用顶空固相微萃取-气相色谱质谱联用技术(GC-MS)和嗅闻技术(GC-O)、感官评价以及快速气相电子鼻对果实的香气成分进行分析。3个品种共检测到71种挥发性成分,"宝交""大将军"和"红宝石"分别有60,70和66种。酯类物质种类最多(21~26种),而醛类物质含量最多(51.37%~63.63%)。其中,丁酸甲酯、丁酸乙酯、乙醛、己酸甲酯、(E)-2-己烯醛、己酸乙酯、乙酸己酯、芳樟醇在3个样品中具有较高的含量及香气强度,为草莓的主要特征香气物质。经感官评价,"宝交"较强甜香气的来源可能是由于2-戊酮的存在;"大将军"青香和花香更强,青香可能由于它具有更高的己醛和反式-2-己烯醛含量,而花香可能来源于芳樟醇、橙花叔醇和β-紫罗兰酮。由快速气相电子鼻可以显示出3个品种草莓很好的区分度。     

Quantitative composition of volatile constituents in cultivated strawberries,Fragaria ananassa cv. senga sengana,senga litessa and senga gourmella

The volatile components of cultivated strawberries Fragaria ananassa cv. Senga Sengana, Senga Litessa and Senga Gourmella were studied by gas chromatography-mass spectrometry. Employing standard-controlled aroma separation by combined vacuum distillation-liquid-liquid extraction, as well as prefractionation on silica gel, the aroma substances of freshly harvested and deep-frozen strawberries from two growing seasons were quantitatively determined by gas chromatography. Methyl and ethyl butanoate, methyl and ethyl hexanoate, trans-2-hexenyl acetate, trans-2-hexenal, trans-2-hexen-1-ol as well as 2,5-dimethyl-4-methoxy-3(2H)-furanone were identified as main volatile components. In comparison to Senga Litessa and Senga Gourmella, Senga Sengana showed higher amounts of aroma compounds. In general, deep-freezing resulted in decreases of the concentrations of most of the aroma substances, but higher amounts of 2,5-dimethyl-4-methoxy-3(2H)-furanone were found in deep-frozen berries than in the freshly harvested ones.     

Impact of postharvest methyl jasmonate treatment on the volatile composition and flavonol content of strawberries

BACKGROUND: Although strawberry aroma is very complex, certain compounds have been described as main contributors, i.e. furanones, aldehydes, alcohols, sulfur compounds and particularly methyl and ethyl esters. In addition, strawberries possess potent antioxidant activity because of their high content of phenolic compounds. Among them, flavonols are highlighted as important antioxidant compounds in strawberry. The objective of this study was to assess the effect of methyl jasmonate (MJ) on the composition of the major contributors to aroma and on the content of certain flavonols in strawberry fruits. RESULTS: The levels of all studied volatile compounds were significantly affected by MJ treatment, though the individual effect differed according to the specific compound considered. Most of them increased significantly (P < 0.05), except methyl butanoate, which always showed higher levels in untreated strawberries. In contrast to aroma compounds, the change in the concentration of flavonols (i.e. myricetin, quercetin and kaempferol) was not significant in MJ‐treated strawberries. Considering the health‐promoting activity of these compounds, further investigations on the experimental conditions related to the treatment are required to control flavonol bioformation by means of MJ. CONCLUSION: The exogenous application of MJ vapour to strawberry enhances, in general, the production of the most relevant aroma‐active compounds. On the contrary, MJ treatment does not appear to influence the levels of myricetin, quercetin and kaempferol. Thus postharvest MJ treatment is proposed as an approach to obtain improved strawberry fruits in terms of sensory quality and health‐promoting properties. Copyright © 2010 Society of Chemical Industry     

Odour‐active compounds in pineapple (Ananas comosus [L.] Merril cv. Red Spanish)

Application of solid‐phase microextraction, simultaneous distillation–extraction and liquid–liquid extraction combined with GC‐FID, GC‐MS, aroma extract dilution analysis, and odour activity value was used to analyse volatile compounds from pineapple (Ananas comosus [L.] Merril cv. Red Spanish) and to estimate the most odour‐active compounds. The analyses led to the identification of ninety‐four compounds, seventy‐two of them were positively identified. Twenty odorants were considered as odour‐active compounds, from which ethyl 2‐methylbutanoate, 2,5‐dimethyl‐4‐hydroxy‐3(2H)‐furanone, 1‐(E,Z,Z)‐3,5,8‐undecatetraene, ethyl 3‐(methylthio)propanoate, 1‐(E,Z)‐3,5‐undecatriene, ethyl hexanoate and methyl hexanoate were the most odour contributors and contribute to the typical pineapple aroma, while the others are responsible for fruity and sweet odour notes.     

Odour‐active compounds in mango (Mangifera indica L. cv. Corazón)

Simultaneous distillation–extraction combined with GC‐FID and GC‐MS were used to analyse volatile compounds from mango (Mangifera indica L. cv. Corazón) and to estimate the most odour‐active compounds in the fruit. The analyses led to the identification of 167 components, from which 128 were positively identified. The aroma‐active areas in the gas chromatogram were screened by the application of the aroma extract dilution analysis and by odour activity values. Eighteen odorants were considered as the most odour‐active compounds: (E)‐β‐damascenone, ethyl butanoate, (E,Z)‐nonadienal, ethyl 2‐methylpropanoate, (E)‐2‐nonenal, (E)‐β‐ionone, terpinolene, δ‐3‐carene, β‐caryophyllene, ethyl 2‐methylbutanoate, limonene, myrcene, linalool, γ‐octalactone, nonanal, methyl benzoate, 2,5‐dimethyl‐4‐methoxy‐3(2H)‐furanone and hexanal.     

Effect of storage temperatures on antioxidant capacity and aroma compounds in strawberry fruit

The antioxidant capacity (measured as oxygen radical absorbance capacity, ORAC), total anthocyanins, total phenolics, aroma compounds, and postharvest quality of strawberry fruit (Fragaria x ananassa cv. Chandler) kept at 0°C, 5°C, and 10°C were investigated. Strawberry fruit stored at 10°C or 5°C showed higher antioxidant capacity, total phenolics, and anthocyanins than those stored at 0°C. However, the postharvest life based on overall quality was longer at 0°C than at 5°C or 10°C. The production of aroma compounds was markedly influenced by storage time and temperature. Individual aroma compounds were affected differently. For example, ethyl hexanoate, hexyl acetate, methyl acetate, and butyl acetate increased, while 3-hexenyl acetate and methyl hexanoate decreased during storage. In general, strawberries stored at 10°C or 5°C produced higher levels of these volatiles than those stored at 0°C. In conclusion, strawberries stored at 0°C retained an acceptable overall quality for the longest storage duration; however, berries stored at temperatures higher than 0°C showed higher content of aroma compounds and antioxidant capacity during the postharvest period.     

Changes in flavour and texture during the ripening of strawberries

The amount of total volatile compounds, total acidity, total sugar content (degrees Brix) and fruit firmness were used to characterize the degree of ripeness of three strawberry varieties (Carezza, Darselect and Marmolada). A novel concept using solid phase microextraction (SPME) and measurement of total volatile compounds to distinguish between various stages of strawberry ripeness was applied. The carboxene/polydimethylsiloxane SPME fibre was found to be best suited to differentiate between the stages of ripeness. The amount of total volatile compounds rapidly increased near to maturity (between the three-quarters red stage and the dark-red stage). Most of the volatile compounds identified were esters, followed by aldehydes, and alcohols. The most abundant volatile compounds were propyl butanoate, 3-phenyl-1-propanol, butyl butanoate, isobutyl butanoate, 3-methyl butyl butanoate and isopropyl hexanoate. The concentration of green aroma components such as hexanal, trans-2-hexenol and cis-3-hexenyl acetate progressively decreased during the maturation process until they became minor components in mature strawberries.     

Elevated carbon dioxide affects fruit flavor in field‐grown strawberries (Fragaria × ananassa Duch)

The effect of elevated carbon dioxide on fruit quality and aroma volatile composition in field‐grown strawberries (Fragaria × ananassa Duch) was studied. Elevating the ambient CO₂ concentration (ambient + 300, and ambient +600 µmol mol^?1 CO₂) resulted in high fruit dry matter, fructose, glucose and total sugar contents and low citric and malic acid contents. High CO₂ growing conditions significantly enhanced the fruit content of ethyl hexanoate, ethyl butanoate, methyl hexanoate, methyl butanonate, hexyl acetate, hexyl hexanoate, furaneol, linalool and methyl octanoate. Thus, the total amounts of these compounds were higher in berries grown in CO₂‐enriched conditions than those grown in ambient conditions. The highest CO₂ enrichment (600 µmol mol^?1) condition yielded fruit with the highest levels of these aroma compounds. Copyright © 2004 Society of Chemical Industry     

搅拌棒萃取-气相色谱-质谱联用法分析‘媚丽’桃红葡萄酒中的香气成分

采用搅拌棒萃取法-气相色谱-质谱联用技术,对‘媚丽’桃红葡萄酒中的香气成分进行定量检测。结果表 明：‘媚丽’桃红葡萄酒中共检测到55 种香气成分,包括26 种酯类物质、4 种酸类物质、9 种醇类物质、6 种萜烯 类物质、3 种C13-降异戊二烯等。通过计算香气活性值发现,其中12 种香气成分对‘媚丽’桃红葡萄酒的香气有重 要贡献。这些物质是：乙酸乙酯、丁酸乙酯、己酸乙酯、辛酸乙酯、乙酸异戊酯、异丁酸乙酯、异戊酸乙酯、异戊 醇、2-苯乙醇、里哪醇、β-大马士酮和β-紫罗兰酮。感官分析结果表明：‘媚丽’桃红葡萄酒具有玫瑰香、苹果、 草莓、菠萝等香气。     

景芝芝麻香型白酒重要挥发性香气成分研究

芝麻香型白酒是1949年后新发展起来的一种新香型白酒,一直以来对其重要香气成分认识不清。应用顶空固相微萃取（HS-SPME）、液液微萃取（LLME）结合气相色谱-质谱（GC-MS）及气相色谱-氢火焰离子化（GC-FID）检测技术,共分析定量出86种香气成分。其中α-雪松烯和α-萜品醇首次在芝麻香型白酒中被定量,平均浓度分别为45.34μg/L和15.77μg/L。结合香气活力值（OAV）分析,发现景芝酒中重要的香气成分为辛酸乙酯、己酸乙酯、丁酸乙酯、3-甲基丁醛、二甲基三硫、3-甲基丁酸乙酯、2-甲基丙酸乙酯和戊酸乙酯（OAV>1000）。剖析芝麻香型白酒的重要挥发性香气成分,将为芝麻香型白酒的生产质量控制提供理论依据与实践指导作用。      

超高压处理对草莓浆香气成分的影响

为了探讨超高压(UHP)处理对草莓浆香气成分的影响,将鲜榨草莓浆经不同压力高压处理后,采用顶空固相微萃取(SPME)富集,用气相色谱-质谱联用仪(GC-MS)检测超高压处理前后草莓浆香气成分的变化,并用面积归一化法测定各种成分的相对含量。结果表明：超高压处理后草莓浆香气成分发生明显改变,其中以丁酸甲酯、己酸甲酯、己酸乙酯、2,5-二甲基-4-羟基-3(2H)-呋喃酮等发挥主导作用的酯类和醛类等香气物质含量增加最为显著,说明超高压处理可有效增强草莓浆的特征香气。综合分析可得,300MPa超高压处理可有效保留和增强草莓浆主要香气成分含量和种类。因此对草莓加工而言,超高压处理是一种很有前景的冷加工技术。     

Changes in volatile aroma compounds of pineapple (Ananas comosus) during freezing and thawing

Changes in the volatile aroma compounds of pineapple (Ananas comosus) during freezing and thawing were compared against fresh samples to determine the effect of freezing on pineapple flavour. An HS‐SPME–GC–MS analysis showed that the Smooth Cayenne pineapple variety had nineteen volatile compounds, in four classes of compounds including fourteen esters, two hydrocarbons, two sulphur‐containing compounds and one lactone. The main characteristic volatile compounds of the fresh pineapple were methyl hexanoate, ethyl hexanoate, ethyl 3‐methylthiopropanoate and 1‐(E,Z)‐3,5‐undecatriene. Freeze–thaw cycles were associated with the loss of some volatile aroma compounds, particularly the esters which were found to be the main characteristic of fresh pineapples. The freezing and thawing process was found to cause damage to the pineapple tissues due to ice recrystallisation and dehydration which lead to the reduction of volatile aroma compounds.     

Vapour partition of aroma compounds in strawberry flavoured custard cream and effect of fat content

Gas–matrix partition coefficients (k) of volatile compounds of a strawberry flavour added to a complex model system (custard dessert, COST action 921 recipe) were determined. The influence of fat content on the volatility of the strawberry aroma compounds was investigated using full fat milk- (FFM) and skimmed milk- (SM) custards. For the purpose of this study, the phase ratio variation (PRV) method was used because of its easy application for a mixture of volatiles without requiring any calibration. From the 15 aroma compounds present in the flavouring mixture, seven were volatile enough to be detected and concentrated enough to allow the calculation of k values. Gas–matrix partition coefficients were compared to gas–water partition coefficients. For some aroma compounds (ethyl hexanoate, ethyl butanoate, and hexanal) a significantly lower k value was observed in FFM-custard than in water, indicating a retention effect caused by the matrix. As expected, the fat content and the hydrophobicity of the volatile compounds were of great importance to explain the differences between partition coefficients in SM custards and in FFM custards: for SM-custard, a higher release in the vapour phase was observed than for FFM-custard; the more hydrophobic the aroma compound, the higher the effect. Moreover, ethyl butanoate and hexanal were less retained in SM-custard than in water. This may be attributed to a salting-out effect due to sucrose.     

Aroma profile and volatiles odor activity along gold cultivar pineapple flesh

Physicochemical attributes, aroma profile, and odor contribution of pineapple flesh were studied for the top, middle, and bottom cross-sections cut along the central axis of Gold cultivar pineapple. Relationships between volatile and nonvolatile compounds were also studied. Aroma profile constituents were determined by headspace solid-phase microextraction at 30 °C, followed by gas chromatography/mass spectrometry analysis. A total of 20 volatile compounds were identified and quantified. Among them, esters were the major components which accounted for 90% of total extracted aroma. Methyl butanoate, methyl 2-methyl butanoate, and methyl hexanoate were the 3 most abundant components representing 74% of total volatiles in pineapple samples. Most odor active contributors were methyl and ethyl 2-methyl butanoate and 2,5-dimethyl 4-methoxy 3(2H)-furanone (mesifuran). Aroma profile components did not vary along the fruit, but volatile compounds content significantly varied (P < 0.05) along the fruit, from 7560 to 10910 μg/kg, from the top to the bottom cross-sections of the fruit, respectively. In addition, most odor-active volatiles concentration increased from the top to the bottom 3rd of the fruit, concurrently with soluble solids content (SSC) and titratable acidity (TA) differences attributed to fruitlets distinct degree of ripening. Large changes in SSC/TA ratio and volatiles content throughout the fruit found through this study are likely to provoke important differences among individual fresh-cut pineapple trays, compromising consumer perception and acceptance of the product. Such finding highlighted the need to include volatiles content and SSC/TA ratio and their variability along the fruit as selection criteria for pineapples to be processed and quality assessment of the fresh-cut fruit.     

Changes in the composition of aromatic compounds and other quality parameters of strawberries during freezing and thawing

Six strawberry cultivars were analysed, as fresh and as frozen and thawed fruit, for their content of anthocyanins, ascorbic acid, titratable acid, soluble solids and aromatic compounds. During freezing and thawing the content of titratable acid and soluble solids remained constant, whereas the content of anthocyanins and ascorbic acid decreased. The composition of aromatic compounds was also changed during freezing and thawing and greatest decreases were found fortrans-2-hexenal and hexanol. The content of volatile acids, linalool and methyl hexanoate was doubled after freezing and thawing, and, for all cultivars except from Pandora and Dania, ethyl butanoate and ethyl hexanoate increased strongly. This cultivar-dependent ethyl ester formation occurred during thawing rather than during freezing.     

Volatile constituents of feijoa—headspace analysis of intact fruit

The volatile constituents emanating from intact feijoa fruit during storage were concentrated on to Tenax GC using a headspace trapping technique. Analysis by gas chromatography and gas chromatography-mass spectrometry led to the identification of 11 components of which myrcene, ethyl hexanoate, trans β-ocimene, 2-heptyl butanoate, cis hex-3-enyl butanoate and cis hex-3-enyl hexanoate are reported for the first time. Measurement of sequential changes in the aroma profile following natural abscission of the fruit suggests that ethyl benzoate may be an important compound in determining optimum ripeness of feijoa. Gas chromatographic sniffing trials on the headspace concentrate led to the conclusion that ethyl butanoate, methyl benzoate and ethyl benzoate are important in the aroma of intact feijoa fruit.     

Evaluation of volatile flavour compounds from cashew apple (Anacardium occidentale L) juice by the Osme gas chromatography/olfactometry technique

The headspace volatile components of the juice of cashew apples from a commercial Brazilian dwarf genotype were separated by high‐resolution gas chromatography and identified by GC/MS. Five judges evaluated the GC effluents using the Osme technique in order to determine the importance of each compound to the characteristic cashew aroma. Esters methyl 3‐methyl butanoate, ethyl 3‐methyl butanoate, methyl butanoate, ethyl butanoate, ethyl trans‐2‐butenoate and methyl 3‐methyl pentanoate were important to the sweet, fruity and cashew‐like aroma. Cis‐3‐hexenol, hexanal and 2‐methyl‐2‐pentenal presented different green notes. In spite of the flame ionisation detector being unable to detect sulphur compounds, the olfactometric analysis revealed chromatographic regions where sulphur‐like odours were perceived by the Osme sensory panel. The most intense unpleasant odour was due to 2‐methyl butanoic acid, which was described as very stinky. The sensory panel showed good olfactory sensitivity and reproducibility. Sensory and instrumental data correlation allowed a greater understanding of the role of several volatile compounds in the sensory quality of the juice. Copyright © 2003 Society of Chemical Industry