Qualitaetserhaltung bei verschiedenen Beerenobstarten durch Lagerung in Kontrollierter Atmosphaere (CA) und in erhoehten CO2-Konzentrationen, unter besonderer Beruecksichtigung des Vitamin C-Gehalts und der Entstehung von Fremdgeschmack (Off-flavor)

Available from: Hannover Univ. (Germany). Universitaetsbibliothek / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekSIGLEDEGerman

Effects of modified atmosphere packaging on postharvest quality and storage of mature green and pink tomatoes

The effects of modified atmosphere packaging (MAP) on storage and postharvest quality of F1 hybrid tomatoes (Lycopersicon esculentum Mill. 'Zorro') were investigated. Tomatoes were harvested at mature green and pink stages and packed with Xtend® bags. Air stored fruits were considered as control. All samples were stored at 12°C with 90% RH for 35 days. Weight loss, elasticity, skin color, ethylene production, lycopene, polygalactronase (PG) activity and decay parameters were investigated with intervals of 7 days. At the end of the storage, MAP of either mature green or pink fruits reduced the weight loss and decay. Among mature green tomatoes stored in MAP, the amount of decayed fruit was 5.88%, while this level for control fruits was 19.61%. MAP also delayed the increase of ethylene emission rate (detected by GC) and polygalactronase activity and the higher elasticity obtained from MAP compared to control. At the end of the storage, elasticity values were significantly higher in fruits of both maturity stages stored in MAPs (69.50 and 56.13 shore for mature green and pink fruits, respectively) than those of the control groups (55.73 and 46.53 shore for mature green and pink stages, respectively). Furthermore MAP alleviated the increment of PG activities in fruits of both stages. Mature green fruit had lower weight loss, decay, lycopene accumulation, ethylene production values, whereas they had higher hue angle and elasticity values than pink fruits. The general qualities of MAP fruits were better than those of air stored fruits. Overall findings indicate that MAP was able to store mature green for 35 days without significant decreases in quality characteristics

Influence of different concentrations of 1-methylcyclopropene on the quality of tomato harvested at different maturity stages

PubMedID: 21918990Background: A wide range of 1-methylcyclopropene (1-MCP) concentrations as well as various treatment durations have been studied in tomatoes by different researchers. However, little is known about interaction of 1-MCP doses and maturity stages of tomatoes. Therefore the effects of different concentrations of 1-MCP on storage and postharvest quality of 'Zorro' tomatoes harvested at mature green or pink maturity stages were investigated in a 2-year trial study. Results: Higher concentrations of 1-MCP delayed and/or inhibited all parameters related to fruit ripening, such as lycopene, chlorophyll, surface color, polygalacturonase (PG) activity and soluble solids content/titratable acidity (SSC/TA), and these effects were greater in tomatoes harvested at the mature green stages. Lower concentrations of 1-MCP slightly reduced the loss in general quality features compared with untreated tomatoes. Conclusion: The results suggest that 1-MCP, especially at higher doses, is effective for delaying ripening of mature green tomatoes. Mature green fruits treated with 1000 nL L -1 1-MCP were stored for 35 days without significant decreases in quality characteristics such as elasticity, surface color and SSC/TA with certain physiological processes (ethylene production, PG activity, lycopene synthesis). © 2011 Society of Chemical Industry

Effect of high CO2 and controlled atmosphere (CA) storage on the fruit quality of raspberry

In storage experiments with raspberry, cv. 'Meeker', three different storage techniques were used: a) Cold storage at 1 °C, b) Cold storage 1 °C plus high CO2 treatments (10 %, 20 %, 30 % CO2), without O2 regulation (high CO2) and c) Cold storage 1 °C plus high CO2 (10 %, 20 %, 30 % CO2) plus 2 % O2 (CA storage). At 3 day intervals and after additional 1 day shelf-life at 20 °C raspberries were analysed for several quality parameters like percent sound fruit, total soluble solids, titratable acidity, ascorbic and dehydroascorbic acid, ethanol, and acetaldehyde content and respiration. During the 9 day storage period, raspberries tolerated CO2 concentrations as high as 30 %. The rate of sound fruits in CA and high CO2 treatments were found higher than the control treatment. During 9 days in CA or high CO2 storage, raspberries had shown higher ethanol content but lower respiration rates. Reduction of oxygen to 2 % in combination with high CO2 concentrations (CA) did not bring a considerable beneficial effect in comparison to high CO2 treatments without O2 reduction. Raspberry cv. 'Meeker' can thus be stored successfully in 20 % CO2 at 1 °C for about 1 week plus 1 day shelf life

Effects of 1-methylcyclopropene and modified atmosphere packing on postharvest life and quality in tomatoes

The effects of 1-methylcyclopropene (1-MCP), modified atmosphere packaging (Xtend, StePac L.A. Ltd., Tefen, Israel) and their combination were investigated on storage and quality maintenance of tomatoes cv. "Perla" harvested at two maturity stages. 1-MCP treatment was performed in 1,000nL/L doses for 24h while untreated fruits were considered as control. Fruits were stored at 12C with 90% relative humidity for 21 days. Weight loss, skin color, elasticity, lycopene, ascorbic acid, soluble solid content (SSC), titratable acidity (TA) and SSC/TA were evaluated with the intervals of 7 days. MAP with and without 1-MCP reduced weight loss and maintained to elasticity compared with control and 1-MCP alone. Nevertheless, 1-MCP or its combination with MAP significantly delayed changes in parameters related to fruit ripening, such as skin color, lycopene, TA and SSC/TA increase in both ripening stages. Overall results indicated that the combination of 1,000nL/L 1-MCP and modified atmosphere package was the most effective treatment in both ripening stages. © 2011 Wiley Periodicals, Inc

Exogenous ethylene accelerates ripening responses in Bartlett pears regardless of maturity or growing region

Mature-green 'Bartlett' pears (Pyrus communis L.) were harvested weekly during the commercial harvest period to explore the influence of three climatically diverse growing locations and of harvest maturity on the requirement for C2H4 treatment at harvest to achieve uniform ripening and good eating quality. Pears were treated with ethylene (air + 10 Pa C2H4) or air (untreated) at 20°C for 24 h to determine their responsiveness to C2H4, including the effect on 1-aminocyclopropane-1-carboxylic acid (ACC) synthase (ACC-S) and ACC oxidase (ACC-O) activity during subsequent ripening at 20°C. Exposing freshly harvested and non-chilled 'Bartlett' pears to 24 h exogenous C2H4 treatment concurrently stimulated the activity of ACCS and ACC-O, and resulted in higher C2H4 production, which advanced the rate of ripening and reduced the firmness variability regardless of maturity, growing region or season. Differences in the rate of softening between ethylene-treated and untreated pears were greatest for fruit from earlier harvest dates. The ripening capacity of 'Bartlett' pears developed as the fruit matured on the tree, resulting in higher ACC-S activity, ACC-O activity and C2H4 production, but the ripening capacity was not fully induced unless the fruit were cold stored or treated with exogenous C2H4. Ethylene production was higher in fruit from growing locations that experience cooler preharvest temperatures and fruit from later harvests within each location. Pears harvested from warmer growing regions as well as early harvests from later growing locations which experience cooler preharvest night temperatures can benefit from treatment with C2H4 after harvest to promote uniform ripening.We gratefully acknowledge the invaluable help and advice of Murray Clayton on statistical analysis. We thank David Bouck, George Sakaldasis and Michelle Lauer for their excellent technical assistance. We also thank Doug Hemly of Greene and Hemly, Inc., David Elliot of David J. Elliot & Sons, Tom Thomas of Alex R. Thomas & Co., and Don Eutiner for their cooperation and donation of fruit used in this study. Research was supported in part by the California Pear Advisory Board

Temperature and exposure time during ethylene conditioning affect ripening of Bartlett pears

PubMedID: 10691611Freshly harvested early- and mid-season Bartlett pears (Pyrus communis) were treated with ethylene (air plus 10 Pa C2H4) or air at 5, 10, and 20 °C for 24 and 48 h (experiment 1) and at 5 and 10 °C for 48, 72, and 96 h and at 20 °C for 24 h (experiment 2). Following C2H4 or air treatment at different temperatures and durations, pears were transferred to 20 °C in air for ripening. Bartlett pears were evaluated for firmness, color, respiration, C2H4 production, and activities of 1-aminocyclopropane-1-carboxylic acid synthase (ACC-S) and 1-aminocyclopropane-1-carboxylic acid oxidase (ACCO). Ethylene action was temperature dependent. The duration of C2H4 conditioning needed to fully induce ripening was longer at lower temperatures: 72 h at 5 °C, 48 h at 10 °C, and 24 h at 20 °C. Cold storage in air for as little as 3-4 days at 5 or 10 °C appeared to hasten subsequent ripening, but to a lesser extent than pears kept for 2 weeks at - 1 °C in air. Despite a significant increase in ACC-S activity in pears treated with C2H4 at 5 °C, there was not a simultaneous increase in ACC-O activity, resulting in low C2H4 production that was insufficient to generate the threshold endogenous levels of C2H4 required for ripening. Contrary to previous findings with pears, these data indicate that ACC-O could be a rate- limiting step in C2H4 biosynthesis

Lipid characteristics of Turkish and Iranian pistachio kernels

The fat content and fatty acid composition of 9 Turkish pistachio varieties grown in Ceylanpinar, Sanliurfa-Turkey and 36 Iranian pistachio varieties and genotypes grown in Iran were investigated. Twenty seeds from each variety were randomly selected and the kernels were analyzed. Oil extraction and fatty acid methyl ester formation were done in a single step and the composition of fatty acids was determined by gas chromatography. Fat content of the Turkish varieties ranged from 48.55% to 58.50% and Iranian varieties ranged from 47.65 to 63.31 %. Palmitic acid, which is the main saturated fatty acid, ranged from 8.27% to 11.07% in Turkish and 8.40% to 10.87% in Iranian varieties. Palmitoleic acid content was less than 1% in Turkish cultivars, and ranged between 0 and 1.46% in Iranian varieties. The stearic acid content of the Turkish pistachio varieties ranged from 0.20% to 2.79% whereas Iranian varieties contained from 0.44 % to 1.80% stearic acid. Oleic acid content ranged from 53.16% to 72.63% in Turkish varieties and from 51.80% to 71.23% in Iranian nuts. Linoleic acid content was between 16.58 and 35.40% in Turkish varieties and between 17.36% and 35.16% in Iranian varieties