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Goliáš J., Létal J., Veselý O., 2012. Eff ect of low oxygen and high carbon dioxide atmospheres on the formation of volatiles during storage of two sweet cherry cultivars. Hort. Sci. (Prague), 39: 172-180.Th e aroma profi les of two sweet cherry cultivars Kordia and Vanda were investigated during storage at diff erent oxygen and carbon dioxide levels and at a low temperature using solid phase microextraction gas chromatography combined with mass spectrometry (SPME-GC-MS). Th e most abundant aroma volatiles observed in both sweet cherry cultivars were alcohols, esters, terpenoids and aldehydes. Fifteen alcohols (but principally ethan-1-ol, (E)-2-hexen-1-ol and phenethyl alcohol) provided approximately 39% of the total volatile production and eight esters (principally (E)-2-hexenyl acetate and pentyl butyrate) were responsible for another 39% of the volatile production. Four terpenoids (principally limonene and α-linalool) were responsible for a further 15% of volatile production, and 10 aldehydes (principally (E)-2-hexenal and (E)-2-octen-1-al) were responsible for the remaining 7% of total volatile production. However, out of all the volatile compounds detected, a total of just 6 compounds (phenethyl alcohol, (E)-2-hexenal, (E)-2-octen-1-al, pentyl butyrate, (E)-2-hexenyl acetate and limonene) made up 80% of the total volatile production. Fruit stems remained green during all 54 days of the storage period, although one tenth of the stems slowly dessicated in each of the three controlled atmospheres. Th is is in marked contrast to the stems of fruit held in a regular atmosphere, which turned completely brown.

Physico-chemical changes included a significant decrease in firmness during post-harvest ripening, whereas the levels of total soluble solids were found to be very similar. Ethylene as a parameter of ripening contributed to the resolution of cultivars in the over-ripe phase. On the other hand, fruit softening was not a useful parameter for distinguishing cultivars. 59 of volatiles were determined by the static headspace SPME gas chromatography with mass spectrometry and included 18 alcohols, 12 aldehydes, 10 esters, 11 terpenes, 5 lactones and 3 miscellaneous. Actually, the production of alcohols at ripe stage had almost been completed, since at the over-ripe stage they increased only slightly. Terpene levels were highest for the medium-late cultivars (Orangered, Velkopavlovická, Pinco, Silvercot and Leskora); they were predominantly limonene, α-terpineol and β-Ionone. The decrease in the concentration of terpenes in over-ripe fruit was statistically significant. There are six compounds (2-methylbutan-1-ol, 2-methylbutanal, n-hexylbutanoate, 3-methyl-3-methylbutyric acid, γ-caprolactone and γ-octalactone) which taken together can be used to distinguish the two different stages of maturity, ripe and over-ripe. The most abundant of these are γ-caprolactone and γ-octalactone, followed by 2-methylbutan-1-ol. If the volatiles from the cultivars used in this investigation are compared using cv. Bergeron as a standard, then only 10 are required to separate each variety at the over-ripe phase. Principal component analysis clearly separated the cvs Velkopavlovická and Bergeron from all the others, which probably reflects major differences in the production of volatiles and ethylene.Keywords: volatile compounds; ethylene; respiration rate; firmness; HP-SPME-GC-MS Optimum fruit quality depends upon a number of factors, including the fruit developmental stage at the point of harvest and the subsequent changes during the period of post-harvest maturation. Ripening to achieve optimum quality means that there must be good aroma development (Botondi et al.

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Goliáš J., Létal J., Balík J., Kožíšková J. (2016): Effect of controlled atmosphere storage on production of volatiles and ethylene from cv. Zaosuli pears. Hort. Sci. (Prague), 43: 117-125.Harvest-mature fruits of the pear cv. Zaosuli (Pyrus bretschneideri Rehd.) were stored at 1.0-1.5°C under two different experimental atmospheres. The controlled atmosphere (CA) had low oxygen (2.0%) and high CO 2 (7%), while the regular atmosphere (RA) had 20.9% O 2 and 0.1% CO 2 . Sixty-four volatile compounds were subsequently detected and quantified by solid phase micro-extraction (SPME) including 1 hydrocarbon, 16 alcohols, 15 aldehydes, 4 ketones, 15 esters, 8 terpenes, 2 lactones and 2 fatty acids. The principal component analysis of data was carried out to assess the effects of these post-harvest storage conditions in comparison to fruit stored in air at room temperature for 5 days. Thirteen compounds were found to be sufficient to differentiate the two different pear treatments, which were followed by subsequent warming to 20°C. The observed differences in the production of volatiles between the start of storage and 40 days later (RA), or 40 days later (CA), are principally due to just four compounds, namely n-hexanol, 2-furaldehyde, cis-geraniol and α-damascenone. Ethylene production is also lower in the CA treatment. The higher concentration of CO 2 in the CA treatment causes a rise in respiration rates due to anaerobic respiration.

A total of 124 identical volatile aromatic compounds were identified during storage of the European ‘Conference’ and the Asian ‘Yali’ pear cultivars in different temperature conditions. Only 5 volatiles were statistically differentiated in both cultivars by means of successive multinomial logistic regression: 3-methylbutan-1-al, 2-methylpropyl acetate, 2-methoxy-4-vinylphenol, ethanol, and eugenol. Significant statistical data obtained by sequential multinomial logistic regression developed by the principal component analysis (PCA) procedure and distinguishing the different ‘Conference’ and ‘Yali’ pears storage regimes were dimensionless in themselves. The PCA components were expressed as linear combinations of selected variables necessary to distinguish the cultivars. The eigenvalues of the first three PCA components differentiated the storage regimes. For each principal components were selected volatiles with a probability higher than 0.4. Combinations created from PCA components were shown using clusters distinguishing the pear storage conditions used. Analytical data from SPME-GC/MS such as concentration (ng kg−1) demonstrated multiple and order-of-magnitude differences between the ‘Conference’ and ‘Yali’ pears. The ‘Yali’ cultivar exhibited significantly higher concentrations of eugenol.

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