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`Anjou' pears (Pyrus communis L.) were placed in controlled-atmosphere (CA) storage immediately after harvest (<24 hours) or after a 10-day delay in refrigerated storage, and held there for 9 months at 1C. Oxygen in all atmospheres was 1.5% and CO2 was at either 1% or 3%. Atmospheres in the flow-through system were computer-controlled at ±0.1%. After removal from CA storage, pears were evaluated immediately and after ripening at 21C for 8 days. Pears stored in 3% CO2 were firmer, greener, and displayed less scald, internal breakdown, and stem-end decay than pears stored in 1% CO2. In addition, no internal discoloration of `Anjou' pears was evident when held with 3% CO2. `Anjou' pears held in 3%. CO2 retained the ability to ripen after long-term storage. A 10-day delay in atmosphere establishment had little or no influence on the long-term keeping quality or ripening ability of `Anjou' pears.
Fruit growers and shippers have suggested that excessive rates of boron (B) in foliar nutrient sprays may reduce quality of stored apples. Foliar B sprays were applied by handgun in mid-July to bearing apple trees (Malus domestica Borkh. cv. Starking) at rates of 0, 11.3,22.6 g B/tree. Fruits of uniform size (220 g) were analyzed for B content at harvest and for quality indices at harvest, after 10 days ripening postharvest, after 3 months refrigerated air storage, and after 8 days ripening poststorage. Whole fruit B concentration was directly proportional to B application rate. At all sampling times fruit firmness, soluble solids, titratable acidity, and internal and external color parameters were independent of whole fruit B concentration. Fruit disorders were unrelated to treatment except for internal breakdown after 8 months refrigerated air storage, which was positively related to whole fruit B concentration. Increases in fruit B were relatively greater in the core tissue, suggesting that some of the applied B entered the fruit through the tree vascular system.
Influences of rootstock on the quality of `Granny Smith' and `Greenspur' apples (Malus domestica Borkh.) were evaluated over an extended harvest period and after cold storage. Apples from trees on M.26 rootstock had the higher firmness, soluble solids concentration (SSC), and Ca content, but poorer external color (red blush) and a higher percentage of solar injury than fruit from trees on seedling or MM.111 rootstock. External greenness was best on apples from MM.111 rootstock. `Granny Smith' apples had higher firmness, soluble solids, acids, and carbohydrate contents, and less scald but poorer external greenness than `Green spur' apples. `Granny Smith' or `Greenspur' apples from M.26 rootstock appeared to mature earlier than those on MM.111.
A sprayable formulation of 1-methylcyclopropene (1-MCP; AgroFresh, Spring House, PA) was applied to ‘Scarletspur Delicious’ and ‘Cameo’ apples in the orchard 1 to 3 weeks before harvest and compared in different postharvest studies with the commercial postharvest 1-MCP fruit treatment (SmartFresh; AgroFresh) and with aminoethoxyvinylglycine (AVG; ReTain; Valent BioSciences, Walnut Creek, CA). Treated apples were held in air storage for 50 to 60 d or in controlled-atmosphere storage for 120 to 125 or 215 to 225 d. With increased concentration, sprayable 1-MCP treatments were effective at controlling flesh firmness loss and internal ethylene concentration (IEC) up to 225 d of storage as well as during a 7-d poststorage shelf life simulation at room temperature. Application closer to harvest improved the effect of sprayable 1-MCP on control of flesh firmness loss and IEC. Concentrations of sprayable 1-MCP above 90 mg a.i./L produced similar fruit effects to 1-MCP. Treatment with 1-MCP showed little effect on soluble solids concentration (SSC), titratable acidity (TA), or skin or flesh color in ‘Delicious’ but slightly increased SSC and TA in ‘Cameo’ apples. AVG applied 4 weeks before commercial harvest controlled IEC nearly as well as either sprayable 1-MCP or 1-MCP during storage, but AVG-treated fruit allowed to ripen for 7 d at room temperature after storage lost much more flesh firmness regardless of storage regime. Sprayable 1-MCP also reduced starch hydrolysis, IEC and fruit drop at harvest. Sprayable 1-MCP may offer new opportunities for effective preharvest management of apple fruit condition, storability, and poststorage fruit quality.
Abstract
Heat penetration data showed that a 3 minute process at 104°C (220°F) with an FMC Steriotort reel speed of 5 rev/min was an adequate process for a high acid food product with an average pH of 3.9. Shear force, succulometer values, and Hunter “b” values were significantly related to maturity, but not to processing time.
Process time can be varied to produce a canned immature, medium-ripe, and ripe ‘Babygold 7’ peach [Prunus persica (L.) Batsch] with characteristics similiar to a commercial product. The most acceptable process for the immature, medium-ripe, and ripe fruit was 7, 9, and 5 minutes, respectively at 104°C with a reel speed of 5 rev/min in the Steriotort. Panelists preferred the ripe and medium-ripe fruit.
Experiments were performed over 3 years to examine the effect that particle film (PF) treatment had on fruit quality of several apple (Malus ×domestica) cultivars in Washington and West Virginia. In the first study, a highly reflective, white, hydrophilic particle-based kaolin mineral (Surround WP) was applied to `Empire' apple in May and June, on a season-long basis, or not at all. Red fruit color was increased by both the PF treatments compared with no treatment in all years. In a second study, the PF material was applied, starting at petal fall, every week for 6 weeks and then every 2 weeks until harvest to `Empire', `Gala', and `Fuji' trees in West Virginia and to `Cameo', `Fuji', and `Gala' trees in Washington. In the latter study, cultivar response to season-long applications varied by year and location. `Empire' consistently had improved red color with season-long applications of PF materials. `Gala' had greater fruit weight and red color with PF application in 1 of 2 years in West Virginia but not in Washington. `Fuji' had greater fruit weight and soluble solids content and `Cameo' had greater soluble solids, higher starch indices, and greater red color in Washington with the PF application. In these studies, application of a PF never reduced the surface red color in apples. A taste panel did not identify quality differences in `Empire' apples treated with PF vs. the control. Cultivar responses to PF applications were variable due to location and yearly environmental characteristics. While particle film technology has value for insect control and reducing sunburn, it has limited value to enhance fruit color due to the inconsistent response.
A quarantine treatment was developed against codling moth (Cydia pomonella L.) (Lepidoptera: Tortricidae) for the sweet cherry (Prunus avium L.) cultivars ('Garnet,' `Brooks,' `Tulare,' `Lapins,' and `Sweetheart') exported to Japan. Specific procedures were required to demonstrate treatment efficacy. Dose-mortality responses were measured for each cultivar at regularly incremented concentrations of methyl bromide for 2 hours at 43 °F (6 °C) compared to the dose-mortality curve of an approved cultivar under the same conditions. Based on the overlap of confidence limits, there were no significant differences between new and approved cultivars in group comparisons. In a confirmation test of efficacy, fumigation with methyl bromide at 0.064 oz/ft3 (64 g·m-3) for 2 hours at 43 °F resulted in complete mortality for all codling moth larvae in the treated cultivars. By convention, fumigation at this or the following concentrations [0.048 oz/ft3 (48 g·m-3) for 2 h at 54 to 63 °F (12 to 17 °C); 0.040 oz/ft3 (40 g·m-3) for 2 h at 63 to 72 °F (17 to 22 °C); 0.032 oz/ft3 (32 g·m-3) for 2 h at 72 °F (22 °C) or above] were considered as an efficacious quarantine treatment against the codling moth in sweet cherries. Except for `Brooks,' fumigation did not significantly influence fruit firmness, soluble solids, or titratable acids. Reduction in fruit and stem quality was more associated with temperature than with methyl bromide concentration. `Tulare,' `Lapins,' and `Sweetheart' could be fumigated with minimal change in fruit quality.
Abstract
Influences of rootstocks on ‘Goldspur Golden Delicious’ apple (Malus domestica Borkh.) respiration rate, ethylene evolution, skin color, firmness, internal color, soluble solids content (SSC), acidity, carbohydrate, and mineral content were evaluated over an extended harvest and after cold storage. At first harvest, fruit from trees on seedling rootstock entered the climacteric (as determined by ethylene evolution) first (after 10 days) followed by fruit from M.26 trees, while apples from trees on MM.111 required 16 days. After 60 days in storage, CO2 and ethylene production were greatest for apples from trees on MM.111 rootstock. Fruit from trees on M.26 developed more external color, contained more acids, had a higher SSC, and appeared to mature between apples grown on the other two rootstocks. Fruit from trees on M.26 were firmer than those on MM.111. Apples from trees on seedling rootstock contained less fructose, glucose, and sucrose than apples from M.26 or MM.111. Calcium content was highest in fruit from trees on M.26.
Confirmatory tests were performed on a two-component quarantine treatment against the codling moth (Cydia pomonella L.) (Lepidoptera: Tortricidae) for seven apple [Malus sylvestris (L.) var. domestica (Borkh.) Mansf.] cultivars ('Delicious,' `Golden Delicious,' `Braeburn,' `Fuji,' `Gala,' `Jonagold,' and `Granny Smith') intended for export to Japan and Korea. Treatment consists of a 55-day cold storage at 40 °F (2.2 °C) or below, followed by a 2-hour methyl bromide fumigation (0.056 oz/ft3 or 56 g·m-3) at 50 °F (10 °C). No eggs or larvae survived this treatment. Comparison tests were conducted on all cultivars to demonstrate no difference in insect responses between a previously accepted cultivar and proposed cultivars. Concentration-mortality responses were determined for each of the components and no statistical differences were found in the regression slopes of pest mortality with controlling variable (either cold exposure or fumigation) among all cultivars. Descriptive mathematical models, developed for the effects of cold storage on egg mortality and for methyl bromide fumigation on larvae mortality, were sigmoid curve equations.
Particle film technology is a developing pest control system for tree fruit production systems. Trials were performed in Santiago, Chile, and York Springs, Pa., Wenatchee and Yakima, Wash., and Kearneysville, W. Va., to evaluate the effect of particle treatments on apple [Malus sylvestris (L.) Mill. var. domestica (Borkh) Manst.] leaf physiology, fruit yield, and fruit quality. Leaf carbon assimilation was increased and canopy temperatures were reduced by particle treatments in seven of the eight trials. Yield and/or fruit weight was increased by the particle treatments in seven of the eight trials. In Santiago and Kearneysville, a* values of the fruit surface were more positive in all trials although a* values were not increased in Wenatchee and Yakima. Results indicate that particle film technology is an effective tool in reducing heat stress in apple trees that may result in increased yield potential and quality.