-
[show abstract]
[hide abstract]
ABSTRACT: Modified atmosphere packaging (MAP) is widely used to maintain the quality of fresh-cut produce by matching the oxygen transmission rate (OTR) of the packaging film to the respiration rate of the packaged product. The effect of the interaction between film OTR and the initial headspace O2 on quality of fresh-cut vegetables has not previously been reported. Romaine lettuce leaves were sliced, washed, dried and packaged with film OTRs of 8.0 and 16.6 pmol s−1 m−2 Pa−1, and with initial headspace O2 of 0, 1, 2.5, 10 and 21 kPa. Packages were hermetically sealed and stored at 5 °C for up to 14 days. For samples packaged in 16.6 OTR film, increasing the initial headspace O2 concentration delayed O2 depletion within the packages, hastened the onset and increased the intensity of discoloration, and inhibited the development of CO2 injury, acetaldehyde and ethanol accumulation, off-odors and electrolyte leakage. With 8.0 OTR-packaged lettuce pieces, ≤1 kPa initial headspace O2 treatments induced an essentially anaerobic environment within the packages and increased acetaldehyde and ethanol accumulation and off-odor development. Increasing the initial O2 concentration above 1 kPa in 8.0 OTR packages transiently increased O2 concentrations and reduced fermentative volatile production, off-odors, electrolyte leakage and CO2 injury. Regardless of initial headspace O2 concentration, all 16.6 OTR-packaged samples had severe discoloration after 14 days of storage. Quality was better maintained in 8.0 OTR-packaged lettuce pieces as the initial headspace O2 concentration was increased. A 21 kPa initial O2 treatment of 8.0 OTR-packaged lettuce maintained good quality throughout storage and had the best overall quality score. Copyright © 2005 Society of Chemical Industry
Journal of the Science of Food and Agriculture 08/2005; 85(10):1622 - 1630. · 1.44 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: Development of fresh-cut apple products requires consideration of cultivars that store well as both intact and fresh-cut fruit. We compared the instrumental and sensory quality of 2 apple cultivars, Granny Smith and Fuji, that are used for fresh cutting with 2 new cultivars, Pink Lady and GoldRush, which were considered to have quality characteristics suitable for fresh cutting. Firmness, titratable acidity (TA), soluble solids content (SSC), and aromatic volatile concentration were measured in intact fruit of the 4 cultivars during 12 mo storage in air at 0 °C and during 3 wk storage at 5 °C as fresh-cut slices. After 1 wk storage as fresh-cut slices, sensory evaluations for acceptability of flesh and peel appearance, flavor, texture, and overall eating quality were performed. During storage, GoldRush apples maintained > 80 N firmness, approximately 17% SSC, > 0.5% TA, and had high aromatic volatile production, that is, maintained quality better than the other cultivars. The quality and shelf stability of GoldRush slices were also as good as or better than slices from the other cultivars, whereas Granny Smith slices generally rated lower than the other cultivars. The acceptability of flavor, texture, and overall eating quality of GoldRush slices was as good as that for Pink Lady and Fuji. The quality of GoldRush apples can be maintained throughout the year in refrigerated air storage and still remain suitable for fresh-cut processing. The results indicate that GoldRush and Pink Lady are 2 promising new, high-quality apple cultivars for fresh cutting. Keywords: fresh-cut fruit, Malus × domestica, postharvest quality, respiration rate, shelf life
Journal of Food Science 05/2005; 70(5):S317 - S324. · 1.66 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: ADDITIONAL INDEX WORDS. CO 2 injury, electrolyte leakage, oxygen transmission rate, postharvest technology ABSTRACT. Fresh-cut tissues are subjected to severe injury during preparation that leads to increased respiratory activ-ity and quality deterioration. Modifi ed atmosphere packaging (MAP) has been used to maintain quality of fresh-cut produce, but O 2 depletion and excessive CO 2 accumulation can be injurious. This study was conducted to evaluate the effect of delayed packaging and MAP using two different oxygen transmission rate (OTR) fi lms 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 fi lms having OTRs of 8.0 and 16.6 pmol·s –1 ·m –2 ·Pa –1 , fl ushed with N 2 to reach an initial headspace O 2 level of 1.5 kPa O 2 , and stored at 5 °C for up to 14 days. Delayed packaging affected gas composition, fermentative volatile production, off-odor development, color, CO 2 injury, and tissue electrolyte leakage. With increasing delay be-fore packaging, fermentative volatile production, off-odor development, and CO 2 injury progressively decreased and discoloration increased. The modifi ed atmospheres obtained with 16.6 OTR fi lm increased discoloration when present, and generally had less off-odor development and CO 2 injury compared to MAP with 8.0 OTR fi lm. Delayed packaging affected overall quality of fresh-cut romaine lettuce packaged with both fi lms. A 12-hour delayed packaging into packages prepared from 8.0 OTR fi lm maintained quality by inhibiting CO 2 injury, off-odor development, and tissue electrolyte leakage. However, an 8-hour delayed packaging into packages prepared from 16.6 OTR fi lm 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 O 2 during suboptimal OTR fi lm packaging conditions. Packaged fresh-cut vegetables are becoming more and more popular because they are convenient and ready-to-eat. The fresh-cut produce industry has been on a double-digit growth rate in response to an increased demand by consumers. However, fresh-cut produce has limited shelf stability due to rapid quality deterioration (Huxsoll et al., 1989; Jacxsens et al., 2002). The major technical issues associated with packaged fresh-cut romaine lettuce are discoloration and decay. Modifi ed atmosphere packag-ing (MAP) technology has been successfully used to control both discoloration and decay. It is essential to maintain an optimum balance of O 2 and CO 2 in the packages to minimize discoloration and decay. The balanced atmospheres are afforded by the selec-tion of suitable fi lm oxygen transmission rate (OTR), respiring surface area, product weight, and respiration rate (Lakakul et al., 1999). Packages are often fl ushed with N 2 to reach a desired initial O 2 level to increase the O 2 equilibration rate and to control browning immediately after processing. However, this practice faces several challenges due to the large variations in respira-tion rate from different varieties, large seasonal variation, and postharvest storage duration prior to processing. In particular, the large variation in respiration rate often results in O 2 being either too high or too low in the package, resulting in the development of tissue discoloration when O 2 is higher than optimal or tissue The authors wish to thank Willard Douglas for adjusting an automatic system to rapidly measure respiration and ethylene production rates of fresh-cut lettuce. Use of a company name or product by the USDA does not imply approval or recom-mendation of the product to the exclusion of others that also may be suitable.
J. AMER. SOC. HORT. SCI. 01/2005; 130(130):116-123116.
-
[show abstract]
[hide abstract]
ABSTRACT: We compared the eating quality of a new apple cultivar, ‘GoldRush,’ with ‘Golden Delicious’ (one of its parents), ‘Fuji,’ and ‘Granny Smith’ (the latter two often used for fresh-cut apple slices). We also compared a commercial with an in-house processing treatment, NatureSeal for apples and Produce Quality and Safety Laboratory (PQSL), respectively. Intact apples that had been stored for about 6 months were washed, processed into fresh-cut slices, stored, and then served to consumers. Both NatureSeal and PQSL treatments maintained cut-surface color values similar to values at the time of cutting. NatureSeal-treated slices were rated slightly better for texture than those receiving the PQSL treatment, but there was no significant difference in acceptability of appearance or flavor. Acceptability scores for the texture and flavor of ‘GoldRush,’ and of ‘Fuji’ when included, were higher than those of ‘Granny Smith’ and ‘Golden Delicious.’ There were small age and gender biases, with older women liking ‘GoldRush’ less and older men liking ‘Granny Smith’ less than other age groups and cultivars in one study. No instrumental measurement was a satisfactory predictor of sensory acceptability scores. ‘GoldRush’ proved to be a promising new cultivar for fresh-cut apple slices and the in-house processing solution maintained the quality of apple slices similar to that of a commercial processing treatment.
Postharvest Biology and Technology.
-
[show abstract]
[hide abstract]
ABSTRACT: Freshly cut honeydew chunks were dipped for 30 s in a solution containing 1.9 mM hypochlorous acid (ClO) without or with a 40 mM concentration of calcium (Ca) propionate, Ca amino acid chelate formulation (Ca chelate), calcium chloride (CaCl2), or not treated. Respiration and ethylene production rates, firmness, translucency, microbiological and sensory characteristics, surface color, volatile abundance, and tissue calcium content were evaluated during 7 d at 10 °C. Nontreated samples developed the highest respiration and ethylene production rates during storage, followed by samples dipped in ClO, ClO+CaCl2 or ClO+Ca chelate, and ClO+Ca propionate. Calcium salt and chelate treatments more than doubled tissue Ca content and inhibited changes in melon firmness, surface color, and the development of tissue translucency during storage. Treatment with ClO alone increased tissue translucency development, but inhibited surface microbial development. Microbial development was higher on nontreated melon samples than on ClO+Ca propionate-treated samples. Total quality-associated volatile abundance increased throughout storage and was higher in ClO+Ca propionate-treated samples than in other treated and nontreated samples. No sensorial preference was observed by consumer panels among ClO-, ClO+Ca propionate-, or ClO+Ca chelate-treated samples. The results indicate that a sanitary dip with Ca is a better alternative to a sanitary dip alone for quality maintenance and shelf-life stability of fresh-cut honeydew melon tissue.
Postharvest Biology and Technology.
-
[show abstract]
[hide abstract]
ABSTRACT: Quality characteristics and physiology of fresh-cut honeydew cubes harvested in summer and winter were evaluated. Sanitized melon cubes were packaged and held at three different atmospheres; passively formed atmosphere (passive modified atmosphere packaging (MAP)), active flushing of package with 5 kPa O2+5 kPa CO2 at packaging (active MAP), and perforated film package (PFP) and at three different temperature treatments; continuously at 5 or 10 °C or 2 days at 5 °C and transferred to 10 °C for a total of 11 days. Cubes of summer fruit had higher soluble solids content (SSC), respiration rate, and translucency than that of winter fruit. Translucency and off-odor were the main factors in deterioration of cubes. Cubes in active MAP had better color retention, reduced respiration rate and microbial population, and longer shelf-life than those in passive MAP, which was of better quality and had a longer shelf-life than cubes in PFP. The active MAP and 5 °C continuous was the best combination and the PFP and 10 °C continuous was the worst combination among the treatments for retaining quality and shelf-life of honeydew cubes. Quality attributes differed between cubes of fruit available in winter and summer, but the shelf-life was similar for both winter and summer cubes.
Postharvest Biology and Technology.
-
[show abstract]
[hide abstract]
ABSTRACT: Fruit quality, sensory characteristics, and volatiles produced by 'Gala' apples (Malus xdomestica Borkh.) were characterized following regular atmosphere (RA) storage without and with a prestorage heat treatment (38 degrees C for 4 days) or controlled atmosphere (CA) storage at 0 and 2 degrees C for 0 to 6 months plus 7-day shelf life at 20 degrees C. Static CA conditions were 0.7 kPa O2 plus 1.0 kPa CO2, 1.0 kPa O2 plus 1.0 kPa CO2, and 1.5 kPa O2 plus 2.5 kPa CO2. Most of the more abundant volatiles were esters; the rest were alcohols, an aldehyde, a ketone, and an aryl ether. Respiration and ethylene production rates, internal atmospheres of CO2 and ethylene, and volatile levels were reduced following CA storage compared with RA storage without and with a prestorage heat treatment. Magness-Taylor and compression firmness, titratable acidity, and sensory scores for firmness, sourness, apple-fruity flavor, and overall acceptability were higher for CA- than for RA-stored fruit. Soluble solids content and sensory scores for sweetness were similar among all treatments. Quality and sensory characteristics were generally similar in heated and nonheated RA-stored fruit, and between 0 and 2 degrees C in CA- and RA-stored fruit. While one CA regime had a higher CO2 concentration than the others tested, CA effects on quality and sensory characteristics were generally more pronounced at the lower O2 levels. Quality characteristics declined between 2 and 4 months storage. The results indicate that short-term CA storage can maintain instrumental and sensory quality of 'Gala' apples.
-
[show abstract]
[hide abstract]
ABSTRACT: A commercial and three experimental wash treatments for fresh-cut apple slices were evaluated for their ability to affect survival of foodborne pathogens and to maintain quality characteristics measured instrumentally and by sensory analysis. For each apple variety (Fuji and Granny Smith), instrumental firmness, cut surface color, and sensory scores for firmness and flavor of fresh-cut apple slices treated with the commercial and experimental wash solutions were similarly maintained during storage (6 days at 5°C). Prior to their use with apple slices, all three experimental wash solutions reduced the survival of Salmonella serovar Typhimurium and Vibrio cholera by 5 logs or more and the experimental solution at pH 2.0 also reduced survival of Escherichia coli O157:H7, Listeria monocytogenes and Shigella flexneri by at least 5 logs, whereas the commercial wash solution had antibacterial activity only against V. cholera. During treatment of apple slices, the wash solutions changed compositionally over time as indicated by a decrease in conductivity, increases in soluble solids content and osmolality, and changes in pH; and they lost their antibacterial activity. Keeping microbial safety in view, wash solutions should not be reused on multiple batches of sliced apples. Instead, alternative washing strategies that maintain the antimicrobial properties of the wash solutions need to be developed for fresh-cut apple slices.
Food Microbiology.
