the surface of affected roots were circular to ovate and ranged in size from 10 to 50 mm ( Fig. 1A ). The lesions were light brown, with dark borders and some concentric zones evident near the perimeter of the affected tissue. Root tissue within the
Rick D. Peters, Tharcisse Barasubiye, and Joanne Driscoll
Corina Serban, Lee Kalcsits, Jennifer DeEll, and James P. Mattheis
acidity (TA) loss during air storage ( DeEll, 2010 ). Postharvest applications of 1-MCP also can increase CA-related internal disorders such as CO 2 injury, cavities, and internal browning ( DeEll, 2010 ; Watkins and Nock, 2012 ). ‘Honeycrisp’ is a
Renae Moran, Jennifer DeEll, and Cindy B.S. Tong
of maturity can lead to bitter pit, whereas harvest at later stages can lead to chilling injury (CI) during storage in ‘Honeycrisp’ ( Watkins et al., 2005 ). Harvest of ‘McIntosh’ at an early stage can lead to core browning and at advanced maturity to
Federica Galli, Douglas D. Archbold, and Kirk W. Pomper
developed internal discoloration, tissue acidification, and off-flavor aroma ( Archbold and Pomper, 2008 ; Galli et al., 2008 ; Koslanund, 2003 ), common symptoms of chilling injury (CI) in many crops ( Saltveit and Morris, 1990 ). The production of
Randolph Beaudry, Paul Armstrong, and Galen Brown
Elasticity, internal C2H4, CO2, and O2, diameter, firmness, and starch index were determined for ripening `McIntosh', `Red Delicious' and `Golden Delicious' apple fruit. Elasticity, measured by the acoustic impulse response of the apple, has previously been found to correlate with fruit firmness after harvest (Armstrong and Brown, 1992) and was studied as a possible index of apple harvest maturity because it is a rapid, non-destructive measurement that could be adapted for field use. However, elasticity did not correlate with firmness or other maturity parameters for fruit attached to the tree. Fruit temperature influenced internal gas levels, probably due to its effect on metabolic activity. An increase in the temperature-compensated internal CO2 level occurred for fruit having an elevated internal C2H4 concentration (> 0.02 μl/L), which suggested that the climacteric respiratory increase associated with ripening occurred while fruit were attached to the tree.
Kevin M. Keener, Richard L. Stroshine, and John A. Nyenhuis
A 5.40-MHz NMR system was used for measuring the self-diffusion coefficient of water (Dw) and the spin-spin relaxation constant (T2) in apple (Malus ×domestica Borkh.) tissue. The pulsed field gradient spin echo (PFGSE) technique was used to measure Dw, and the Carr-Purcell-Meiboom-Gill (CPMG) technique was used to measure T2. T2 and Dw values were compared for apples with differing amounts of soluble solids concentration (SSC) and with and without internal defects, such as bruising, watercore, and internal browning. `Granny Smith', `Golden Delicious', and `Delicious' apples were tested. In `Golden Delicious', Dw highly correlated with apple tissue SSC (P < 0.002, r 2 = 0.68). This indicates that Dw could potentially be used for sorting `Golden Delicious” apples based on SSC, but the coefficient of determination needs to be improved before it would be commercially viable. There were no measurable differences in Dw among healthy apple tissue and tissue affected by either watercore or internal browning. T2 values showed no relationship between healthy apple tissue and bruised tissue in `Golden Delicious' and `Granny Smith'. However, in `Delicious' tissue, T2 values were statistically different between healthy and bruised tissue (P < 0.02). Further comparisons in `Delicious' between watercore and healthy apple tissue showed no differences. But, there were statistical differences found between T2 in healthy apple tissue and tissue with internal browning (P < 0.01). These results indicate that T2 could potentially be used for separating `Delicious' apples with internal browning or with bruising from healthy apples. Titratable acids and pH were correlated for `Golden Delicious' (P < 0.08). This correlation is significant because one may be able to noninvasively measure pH in `Golden Delicious' apples using NMR, which could then be correlated to titratable acids.
Carlos H. Crisosto, R. Scott Johnson, Kevin Day, and Ted DeJong
Studies on the influences of “orchard factors” such as cultivar, harvest time, crop load, fruit canopy position, irrigation, and nitrogen regimes were investigated for plums, nectarines, and peaches at the Kearney Agricultural Center (San Joaquin Valley, Calif.a). These preharvest factors affected internal browning and mealiness incidence differently. More-reliable benefits of treatments to eliminate or reduce internal breakdown may be accomplished by using outer canopy fruit. Optimum quality expression and subsequent consumer satisfaction for each cultivar can be achieved by understanding the role of preharvest factors and harvest time on fruit quality and potential postharvest life.
George H. Clough
Potato (Solanum tuberosum) cv. `Russet Burbank' response to source of side-dress Ca fertilization applied at 0, 28 and 56 kg·ha-1 Ca on fine sandy loam soil was evaluated. Side-dress Ca source and rate did not affect number or total weight of tubers/hill, average tuber weight, or tuber macronutrient concentrations at mid-season. Tuber B concentration was significantly greater with the 12-0-0-10.5 source as compared to the check. Tuber Fe concentration decreased linearly as 22-0-0-7 rate increased from 0 to 56 kg·ha-1 Ca. No other micronutrient concentration was affected by the applied treatments. Calcium fertilization had no effect on tuber yield, grade distribution, or specific gravity. The predominant internal defect observed was brown center, which was reduced at harvest by side-dress Ca application. Internal quality and french fry color were evaluated after storage for 4 months.
Carlos H. Crisosto, Juvenal G. Luza, David Garner, Guiwen Cheng, and Kevin Day
Peach and nectarine skin discoloration or inking (SD) has become a fruit industry problem in the last decade. Spots on the skin may be black, tan, purple or brown and vary in shape. SD was related with physical abuse of the fruit occurring during handling (harvest and transport operations) within the orchard.
An anatomical study comparing healthy and damaged (black and brown) tissue of different peach and nectarine varieties was done with the Scanning Electron Microscope (SEM) and Light Microscope (LM). This study indicated that only exocarp cell (epiderm and cuticle) damage was associated with SD. The internal compartmentation of the damaged cells was often disrupted with the contents of the cytoplasm and vacuole mixed and expelled. Mesocarp cells were always intact and turgid. The same anatomical and visible tissue injury symptoms were induced on fruit by abrasion treatments.
Allan B. Woolf and William A. Laing
Longitudinal halves of freshly harvested avocado fruit (Persea americana Mill. `Hass') were pretreated at 38C for 1 hour in a water bath, while the other half remained at 20C in air. Then the entire fruit was either treated from 1 to 10 minute at 50C, or held at 20C (controls). Fruit quality (daily evaluation of browning and internal quality when ripe), and pulse amplitude modulated (PAM) fluorescence measurements, were made on the skin of each fruit half 1 hour after hot water treatment (HWT), 3 hours later, and each subsequent day until ripening. The pretreated half of the fruit showed almost no development of external browning during the ripening period, while the nonpretreated halves were severely damaged by HWTs. External browning increased with longer HWT duration. Heat damage was also evident as hardening of the skin when fruit ripened, and such damage was reduced by pretreatment and increased with longer HWT duration. HWT had a rapid and marked effect on chlorophyll fluorescence (Fv/FM ratio) of avocado skin. Whereas fluorescence of control fruit remained constant over the first 5 days, in both pretreated and nonpretreated fruit, within 1 hour of HWT, the Fv/FM ratio had dropped to near minimal levels, with little further change. The value of Fv/FM 3 to 6 hours after the HWT was directly related to the duration of the HWT (P <0.0001). Although pretreatment almost eliminated browning, little effect of pretreatment could be detected in the Fv/FM ratio. There was a strong negative correlation (r = 0.93, P < 0.0001) between external browning and Fv/FM for nonpretreated fruit, but this correlation was not significant for pretreated fruit. We conclude that chlorophyll fluorescence clearly reflects effects of heat on the photosynthetic systems in avocado fruit, but does not detect the alleviation of heat damage by pretreatments.