The histology of external CO2 injury of the skin of `Empire' apples and postharvest factors affecting occurrence of injury were investigated. Injury was greater in a 5% CO2/2% O2 atmosphere than in 2% CO2/2% O2, but incidence was affected by orchard source. Susceptibility to injury was highest during the first 4 weeks of storage, while a postharvest treatment with diphenylamine prevented the disorder. Ethanol reduced injury, but ascorbic acid increased incidence of the disorder. Keeping fruit in air cold storage for 10 days before application of CO2 markedly reduced incidence of CO2 injury. Histological studies showed that external CO2 injury begins at the hypodermis—cortex boundary and spreads outward into the upper hypodermis and inward into outer cortex cells, although the cuticle and epidermis appear unaffected and unbroken. Radial walls of affected cells collapse and become pleated, so that the skin surface sinks below nearby normal regions. Other cellular events include loss of cytoplasmic integrity, coagulation of the protoplast, loss of organelle structure, and cell wall separation. Nondigested starch can be found in cells of affected fruit at the hypodermis—cortex boundary. We conclude that several factors affect fruit susceptibility to CO2 injury, including orchard, antioxidant treatment, and delays before application of CO2.
C.B. Watkins, K.J. Silsby, and M.C. Goffinet
Fanjaniaina Razafimbelo, Jacqueline F. Nock, and Chris B. Watkins
The `Empire' apple cultivar is susceptible to external CO2 injury, a physiological disorder that is expressed as tan-colored, smooth, watersoaked areas that become irregularly shaped, rough, depressed, and wrinkled. 1-Methylcyclopropene (1-MCP) may increase susceptibility of fruit to external CO2 injury during controlled atmosphere (CA) storage. We have investigated the effects of 1-MCP on external CO2 injury of `Empire' apple using several approaches. 1) Fruit were treated with 1%, 2.5%, and 5% CO2 during storage. Higher injury levels were associated with exposure to higher CO2 concentrations. 2) Fruit were exposed to 2.5% or 5% CO2 for 3-week periods throughout storage, otherwise being kept at 1% CO2. Most injury occurred in fruit treated with elevated CO2 during the first 3 weeks of storage, and 1-MCP did not extend the period of susceptibility to injury. 3) Exposure of fruit to CA with 5% CO2 after harvest was delayed for up to 14 days. Susceptibility to injury remained high during the delay in 1-MCP-treated fruit in contrast to untreated fruit. 4) Fruit were treated with 250, 500, and 1000 μL·L-1 diphenylamine (DPA), an antioxidant applied for control of superficial scald that is known to prevent susceptibility of fruit to CO2 injury at 1000 μL·L-1. The DPA eliminated injury in 1-MCP treated fruit, even at 250 μL·L-1. Our data show that 1-MCP increases susceptibility of `Empire' apples to external CO2 injury and extra care is therefore required to avoid fruit losses. Nonchemical means may reduce losses, but only DPA application has been shown to eliminate risk of injury.
Christopher B. Watkins and Jacqueline F. Nock
recommendations for CA storage are available in Michigan, New York, or Ontario because of concern about susceptibility of fruit to CO 2 injury ( Tong and Mader, 2009 ). SmartFresh TM technology, based on the inhibitor of ethylene perception, 1-MCP can help
Yuji Nakata and Hidemi Izumi
by strawberry fruit, thereby making them susceptible to CO 2 injury ( Watkins, 2000 ). Ke et al. (1991) reported that CO 2 levels of >20% caused injury with a change in skin and/or flesh color from red to dark–blue-red in strawberry fruit after 10
Jennifer R. DeEll and Geoffrey B. Lum
elevated CO 2 and chilling conditions, making them susceptible to certain physiological disorders in storage, including external CO 2 injury and flesh browning ( DeEll and Ehsani-Moghaddam, 2012 ; Fawbush et al., 2008 ; Watkins and Nock, 2012
Ji Gang Kim, Yaguang Luo, Robert A. Saftner, and Kenneth C. Gross
Fresh-cut tissues are subjected to severe injury during preparation that leads to increased respiratory activity and quality deterioration. Modified atmosphere packaging (MAP) has been used to maintain quality of fresh-cut produce, but O2 depletion and excessive CO2 accumulation can be injurious. This study was conducted to evaluate the effect of delayed packaging and MAP using two different oxygen transmission rate (OTR) films on quality maintenance and shelf stability of fresh-cut romaine lettuce (Lactuca sativa L.). Romaine lettuce leaves were cut, washed, dried, and placed for 0, 4, 8, and 12 hours at 5 °C in ambient air before packaging. Fresh-cut samples were placed into packages prepared from films having OTRs of 8.0 and 16.6 pmol·s-1·m-2·Pa-1, flushed with N2 to reach an initial headspace O2 level of 1.5 kPa O2, and stored at 5 °C for up to 14 days. Delayed packaging affected gas composition, fermentative volatile production, off-odor development, color, CO2 injury, and tissue electrolyte leakage. With increasing delay before packaging, fermentative volatile production, off-odor development, and CO2 injury progressively decreased and discoloration increased. The modified atmospheres obtained with 16.6 OTR film increased discoloration when present, and generally had less off-odor development and CO2 injury compared to MAP with 8.0 OTR film. Delayed packaging affected overall quality of fresh-cut romaine lettuce packaged with both films. A 12-hour delayed packaging into packages prepared from 8.0 OTR film maintained quality by inhibiting CO2 injury, off-odor development, and tissue electrolyte leakage. However, an 8-hour delayed packaging into packages prepared from 16.6 OTR film was better at maintaining the quality of fresh-cut romaine lettuce at 5 °C for 14 days. The results indicated that delayed packaging could be an alternative method to optimize or balance package O2 during suboptimal OTR film packaging conditions.
Elena de Castro, William V. Biasi, and Elizabeth J. Mitcham
.B. Silsby, K.J. Goffinet, M.C. 1997 Controlled atmosphere and antioxidant effects on external CO 2 injury of Empire apples HortScience 32 1242 1246
C.B. Watkins and F.W. Liu
temperature, high partial pressures of CO 2 (pCO 2 ) as well as factors such as mineral nutrition ( Meheriuk et al., 1994 ; Snowden, 1990 ). Another disorder of ‘Empire’ apples that is important to the industry is external CO 2 injury ( Watkins et al., 1997
Rachel S. Leisso, Ines Hanrahan, James P. Mattheis, and David R. Rudell
rates may affect symptom development. Previous research also reveals increases in ethanol and fermentative odors concurrent with soggy breakdown development ( Smock, 1977 ). Internal CO 2 injury of ‘Honeycrisp’ apple fruit has not been exhaustively
Samuel S. Liu and Yong-Biao Liu
aphid resulted in significant injuries to both romaine and head lettuce in the form of brown stains identical to CO 2 injuries ( Lipton et al., 1972 ; Liu, 2012 ). Because cylindered phosphine is free of ammonia, it is possible that factors other than