Upon the completion of a three-year evaluation of natural occurrence of storage diseases within a range of cultivars or advanced selections and a simultaneous assessment of their other characteristics, an apple ideotype has been proposed that could be used in breeding of new cultivars resistant to these diseases. The ideotype combines the potential of apples for long-term storage with higher skin thickness and toughness, a lower production of ethylene, a higher natural content of calcium, a higher content of total phenolic compounds and antioxidant capacity, a higher flesh firmness, and a higher acidity of juice expressed in pH values. For some of these characteristics, threshold values have been suggested in the paper. The genotypes preselected according to these criteria should be chosen on the basis of the final screening with Pezicula alba inoculum test. The result of the inoculation test should be equal to or better than the standard cultivar Gala. Future research is required to determine the feasibility of the ideotype in routine breeding programs.

Acetaldehyde and ethanol are already present in detectable levels at the time of harvest, under aerobic conditions and in healthy, undamaged fruit. Both metabolites can be detected, at different concentrations, in all cultivars. Several hours after harvest, the levels of acetaldehyde in cultivars Summit, Těchlovan and Kordia were 6.41, 9.78 and 22.00 mg/l, respectively. Both ethanol and acetaldehyde accumulate to significant levels in anaerobically stored cherries, particularly in atmospheres with high levels of CO 2 . The highest levels of ethanol observed, after 31 days of exposure to anaerobic conditions, were in the cultivars Těchlovan (1,159 mg/l) and Summit (1,168 mg/l); both concentrations are are broadly similar. The metabolites decreased after a return to aerobic conditions, but remained higher than the levels first observed. Sweet cherries stored in anaerobic conditions are also sensitive to the development of off-flavours in the first 24 hours after opening the storage box. The very slow ripening of the fruit under anaerobic conditions was satisfactorily quantified by measuring the higher degree of fruit firmness, when the usual, visual attributes of ripeness were almost undetectable. Stems also remained green, in contrast to the usual browning that occurs under normal atmospheres. Discrimination analysis of various parameters observed gave a good resolution of different cultivars. 27tential of ultra-low oxygen (ULO) storage as a practical technique for extending sweet cherry shelf-life. MATERIAL AND METHODS Fruit preparationSweet cherries (Prunus avium cv. Těchlovan, Summit and Kordia) with stems attached were hand harvested on July 6, two days before the optimal harvest stage, from the commercial orchard Agro Stošíkovice at the Horticultural Faculty in Lednice. The fruits were sorted to exclude those with obvious defects or dissimilar states of maturity, based primarily on their appearance. Selected fruits were then transported into small boxes and during two hours they were chilled to 3°C before placing in the various gas mixtures. Preparation of the atmospheres Preparation of atmospheres:Immediately after cooling, the final atmosphere composition was obtained by flushing with nitrogen. To eliminate the possibly excessive influence of CO 2 as a respiration inhibitor, the chambers were connected to absorption tubes filled with solid tablets of KOH, which were mixed with an inert material (polystyrene). Gas mixtures were monitored twice a day, using a dual CO 2 /O 2 analyzer (Arelco, ARC, France). Ethanol and acetaldehyde levelsThe cherries were temporarily stored in a freezer and then defrosted prior to analysis. The juice produced was filtered (25 mm diameter syringe filter, 0.2 μm nylon with glass, Alltech Associates Inc., Belgium). 1 μl aqueous samples were injected into a sample block fitted with Teflon, and analyzed with a gas chromatograph equipped with FID (Chrom 5, Laboratory Equipment, Prague). Separation was achieved on a packed column (Porapak P, 3 mm i.d., 120 cm length), gas...

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Goliáš J., Hic P., Kaňová J., 2010. Effect of low oxygen storage conditions on volatile emissions and anaerobic metabolite concentrations in two plum fruit cultivars. Hort. Sci. (Prague), 37: 145-154.By harvest time, small amounts of acetaldehyde were accumulated in the flesh of plums, such as 0.31 mg/l for the cv. Stanley and 1.03 mg/l for the cv. Valjevka. This relative difference in concentrations remained constant throughout the whole period of storage in a regular atmosphere. The long-term effects of higher concentrations of CO 2 are the same as for very low oxygen concentrations; and significant amounts of ethanol accumulate in the tissue. Out of a total number of 42 different odour compounds identified in the juice, there were 11 alcohols, 6 aldehydes, 17 esters, 2 terpenes, 3 organic acids, and 1 lactone. Very low oxygen atmospheres slow down the production of esters and aldehydes, but have little effect on the production of lactones and terpenes. It was shown that a very low oxygen concentration, without much CO 2 (Fluctuating anaerobiosis treatment), does not encourage the production of significant amounts of ethanol and acetaldehyde in the fruit flesh, but does significantly slow the biosynthesis of aromatic volatiles.

Measurements of titratable acidity, soluble solids, firmness, ethylene production and weight loss were made for five apple cultivars held in cold storage for 100 days. Carbosieve G in the traps of the enrichment column, which has only a moderate affinity for light hydrocarbons, was found to meet the requirements for the optimal thermal desorption of ethylene (130°C for 2 minutes) from the enrichment column to the analytical column. ANOVA showed significant differences in all these five parameters between the five cultivars Golden Delicious Reinders, Resista, Topaz, Meteor and Rubinstep, and also in the course of storage. In all cases, the changes in titratable acids measured during storage were especially significant, but the observed changes in sugar levels, as measured by refractometry, were too variable to be useful in this context. High rates of ethylene production impacted probably only indirectly on the loss of firmness and the other parameters which were measured. Discriminant analysis of the measurements of firmness, ethylene production and titratable acid provided the best means of differentiating the cultivars, although Golden Delicious Reinders and Resista still could not be completely separated. Other parameters (soluble solids and loss in weight) did not contribute to the discriminant resolution.Keywords: apple cultivars; composition; ethylene production; firmness; headspace gas analysis tive Magness-Taylor firmness test is still the industry standard for measuring fruit firmness. In term of consumer acceptability appeared to be according to whether a sweet, hard apple or a juicy, but acidic apple was preferred (Daillant-Spinnler et al. 1996).A wide range of factors influence the resistance of apple cultivars to storage diseases (Blažek et al. 2007), particularly the presence of phenolic compounds, skin thickness and its resistance to mechanical damage. This study used discriminant analysis to compare the performance of five different apple cultivars during cold storage, by measuring the production of ethylene and other, non-volatile compounds, changes in firmness of tissues and weight loss. MATERIALS AND METHODS Choice of adsorbent material for trapping ethyleneDetection of ethylene at trace levels (< 10 ppm) is necessary in order to be able to study the influence of this gas on plant development. Gas chromatography (GC) with FID combined with static headspace analysis is limited by the amount gas that can be reliably introduced into the GC inlet. Measurement by dynamic enrichment concentrates analytes to detectable levels and so increases the detection limits. As an adsorbent material for the traps, Carbosieve III has a high affinity for light hydrocarbons such as ethylene and this makes thermal desorption ineffective. However, the Carbosieve G adsorbent (Supelco Inc., Bellefonte, PA) provides optimal thermal desorption of analytes, at 130°C for 2 minutes, from the enrichment column to the analytical column. Determination of ethylene in intact fruitPrior to sampling the apples were place...

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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.

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