Snap beans (Phaseolus vulgaris L.), when broken during harvesting and handling, develop a brown discoloration on the broken ends which is not removed by processing and is detrimental to the appearance and processed grade. Broken-end discoloration (BED) was controlled when samples were treated before storage with 7500 to 10,000 ppm SO2 for 30 seconds or when samples were stored in controlled atmospheres containing 20 or 30% CO2 for 24 hours. Processed quality attributes of color, flavor, texture, and sloughing were not affected by these treatments. Oxygen levels of 5% or less also controlled BED but caused off-flavors in the canned product. Elevated CO2 levels were not injurious to snap bean quality as long as O2 was maintained at 10% or higher.
The effectiveness of fungistatic atmospheres for postharvest control of Botrytis cinerea Pers. infections on cut rose flowers (Rosa hybrids L.) was investigated. Storing cut `Sonia', `Royalty', and `Gold Rush' roses at 2.5C with 10% CO2 for 5 days, followed by 2 days of cold storage in air, reduced the number of B. cinerea lesions that developed on inoculated and noninoculated flower petals by 77% and 82%, respectively, compared to cold storage for 7 days in air. Higher CO2 concentrations and longer CO2 treatment times reduced disease severity further, but resulted in unacceptable leaf discoloration on some cultivars. No deleterious effects of CO2-enriched storage atmospheres on flower quality, weight gain, or vase life were observed. Storage at 2.5C for 7 days in 2 μl SO2/liter reduced B. cinerea infections on inoculated and noninoculated flowers by 53% and 43%, respectively. No deleterious effects on flower quality, weight gain, or vase life were observed. Higher SO2 levels reduced disease severity further, but caused bleaching of the petal margins and necrosis around leaf wounds.
Mature ‘McIntosh’, ‘Empire’, and ‘Golden Delicious’ apple trees (Malus domestica Borkh.) were sprayed with simulated acid rain solutions in the pH range of 2.5 to 5.5 at full bloom in 1980 and in 1981. In 1981, weekly sprays were applied at pH 2.75 and pH 3.25. Necrotic lesions developed on apple petals at pH 2.5 with slight injury appearing at pH 3.0 and pH 3.5. Apple foliage had no acid rain lesions at any of the pH levels tested. Pollen germination was reduced at pH 2.5 in ‘Empire’. Slight fruit set reduction at pH 2.5 was observed in ‘McIntosh’. The incidence of russetting on ‘Golden Delicious’ fruits was ameliorated by the presence of rain-exclusion chambers but was not affected by acid rain. With season-long sprays at pH 2.75, there was a slight delay in maturity and lower weight of ‘McIntosh’ apples. Even at the lowest pH levels no detrimental effects of simulated acid rain were found on apple tree productivity and fruit quality when measured as fruit set, seed number per fruit, and fruit size and appearance.
Methyl bromide (MB) penetration rates, sorption levels, and concentration.time (CT) products were compared in returnable plastic containers (RPCs) and corrugated grape boxes (CGBs). During a 2.5-hour fumigation, sorption of methyl bromide in RPCs and CGBs was 9.8% and 18.1%, respectively. The lower sorption in RPCs increased the exposure of grapes (Vitis vinifera) to MB. Equilibrium concentrations of MB (concentrations that had stabilized) in RPCs and CGBs were 68.2 and 59.2 g·m-3 (4.26 and 3.70 lb/1000 ft3) respectively. The CT products in RPCs and CGBs were 170.5 and 147.6 g·h-1·m-3 (10.66 and 9.19 lb/h/1000 ft3), respectively, and far below phytotoxic concentrations according to the U.S. Department of Agriculture schedule.
Tuber initiation on rooted potato cuttings has been shown to be favored by shortened photoperiods (2). The objective of this study was to characterize the initiation and growth of tubers on plants in growth chambers and to establish an appropriate covariate for tuber mass measurements. Preliminary data on the effects of sulphur dioxide and nitrogen dioxide on tuber growth are also described.
Potato plants (Solanum tuberosum L.) were propagated in controlled environments from tubers or stem cuttings and exposed to SO2 and/or NO2. Cultivar, propagation method, and air quality affected intumescence formation on leaves. Tuber-propagated ‘Kennebec’ and ‘Russet Burbank’ plants developed intumescences in clean air, SO2, or NO2, but not in a SO2-NO2 mixture, whereas tuber-propagated ‘Superior’ and ‘Norchip’ had little or no intumescence formation. Cutting-propagated ‘Kennebec’, ‘Russet Burbank’, and ‘Norchip’ plants had no intumescence development. Intumescence development may be related to carbohydrate status of plants and maturity classification of cultivars.
Fruit of table grape cvs. Black Monukka, Flame Seedless, Thompson Seedless and Himrod were fumigated with 2, 4 and 6 Deccodione tablets for 30 minutes in a fumigation chamber. Fruit was brought to the cold rooms and stored at 32 F and high relative humidity for upto 10 weeks. Decay control index, freshness of stems and bleaching around the capstem were recorded at 2, 4, 6, 8 and 10 weeks of storage. Size of the smoke particles was determined using an electrical aerosol analyzer.
Fruit was kept in good condition by fumigation with 6 smoke tablets upto 10 weeks. Lower doses failed to control the decay. No bleaching around the capstems commonly associated with sulfur dioxide fumigation was noticed. Majority of the smoke particles were between 0.18 and 0.32 micrometers. Fumigation with Deccodione tablets could be a viable alternative to sulfur dioxide fumigation.
Fruit of Vitis vinifera cvs. Flame Seedless, Thompson Seedless and Black Monukka were fumigated with 4, 6 and 8 Deccodione Smoke Tables (DST) for 30 minutes. Fruit was stored at 32 F and high relative humidity. Decay control index, freshness of stems and bleaching around the capstem were recorded at 4, 8, 12 and 16 weeks of storage. Size of the aerosol particles was determined using an electrical aerosol analyzer. Fruit was analysed for Deccodione residues.
Lower rates of the fungicide gave unsatisfactory decay control. Eight DSTs successfully controlled decay upto a period of 14 weeks. There was no bleaching of pigments commonly associated with sulfur dioxide fumigation. Majority of the aerosol particles were between 0.18 and 0.32 micrometers. Deccodione residues on the fruit were within the acceptable limits established for Deccodione. There was no perceptible difference in taste between treated and control fruit. This method of decay control could provide a viable alternative to sulfur dioxide fumigation.
Refrigerated fresh-cut fruit and vegetables are the most rapidly expanding area in produce sales. Shelf life for minimally processed produce depends on natural product senescence or spoilage organism decay. Shelf life limits, near-aseptic cutting facilities, refrigerated transportation, and refrigerated storage make it possible to ship precut cantaloupe coast to coast on a year-round basis. Thorough cantaloupe surface disinfection reduces potential spoilage organisms and harmful pathogens. We compared using vapor hydrogen peroxide and sulfur dioxide to the current practice of hypochlorite (HOCL) washing to reduce cantaloupe microbial load. After treatment, cantaloupe were stored in unsealed polyethylene bags at 2.2°C for 4 weeks. The HOCL treated fruit were scrubbed and soaked for 5 minutes in a commercial HOCL solution. After 4 weeks, the HOCL washed fruit had reduced visible molds compared to controls. Cantaloupes fumigated for 60 minutes with 5000 or 10,000 ppm sulfur dioxide developed sunken lesions but no significant decay after 4 weeks storage. Cantaloupes, treated 60 minutes with 3 mg·L–1 volume vapor hydrogen peroxide, did not show injury or significant decay after 4 weeks storage. Sulfur dioxide and vapor hydrogen peroxide show promise as alternatives to HOCL.
The occurrence of solution pockets in brined sweet cherries has increased during the past 15 years. Affected fruits exhibit translucent pockets beneath the epidermis, filled with ruptured cell contents and brine solution. Pockets may occur anywhere in the fruit but are commonly at the suture. Affected fruits sometimes are not firm enough to pass through a pitting machine without being torn, increasing cullage and lowering grade. Sweet cherries are brined in a solution of sulfur dioxide and lime rather than the usual salt-brine method used on other crops (4).