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...
An investigation was carried out to establish the basic relationship between mechanical resonance, firmness, chemical composition and ethylene production during the maturity time and the ripening time of peach fruit. The stiffness factor calculated by a non-destructive frequency response technique was compared with biological properties obtained by measurement of chemical composition, firmness and ethylene production in the internal atmosphere of tested fruit. The correlation between the biological multifunction and the mechanical resonance frequency of peach fruit can be expressed by an exponential relationship. Multifactorial index seems to describe the rupture point that for peach fruit coincides with the beginning of climacteric developmental stage, detected by ethylene production. The harmonic signal from PULSE signal generator is swept over the frequency range 50 Hz -1.6 kHz. Fig. 2 presents a typical frequency response of tested peach. The highest peak from the spectrum was used for further processing and calculation of stiffness factor S using (1). The mass of each tested peach fruit was measured with precision balance. Sampling of peach fruitsSouth Haven peach fruits grown in an orchard of the research center were used for measurements. Peaches were harvested in the afternoon, transferred to the room temperature and all the parameters were measured next day. Harvesting intervals started from mid-June with the constant interval of one week during five weeks. 12 peach fruits were measured on each of these five measurement days.At the end of the measurements the ripest peach fruits from the last period were stored at a room temperature, numbered from 1 to 12 and their mechanical properties were measured every day from early ripe stage to late ripe stage (4 days). Measurement of texture propertiesThe peach texture was measured as a penetration test with cylindrical plunger of 8 mm diameter and constant speed 10 mm/min, 8 mm deep into tissue. Force deformation curves from penetration tests were plotted to express the skin resistance of tested peach fruits. The firmness of the tissue of tested peach is obtained from the rupture point. Each fruit was penetrated at the opposed locations to obtain skin deformation curve. The compression force expressed as the firmness for skin and flesh of tested peach was sampled and saved in the hard disk of the computer. The mean of four measurements was used to represent the firmness of each tested peach. Measurement of ethylene in atmosphere of impacted fruitA partial vacuum was applied to the tissue submerged in an aquatic solution. Gas bubbles leave out the fruit, rise in the solution and accumulate at the top of the submerged container. A sample (1 ml) of extracted gas was injected in the stainless steel column (1.2 m × 3 mm) packed with Porapak Q (60-80 mesh). Ethylene concentration was determined using an external standard of 110.7 µl/l ethylene calibration gas certified by Linde Products, Czech Republic. Measurement of chemical compositionTwelve fruits were...
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.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.