Progress 06/23/01 to 09/24/04
Outputs
1. What major problem or issue is being resolved and how are you resolving it (summarize project aims and objectives)? How serious is the problem? What does it matter? Major postharvest losses of fresh produce occur during cold storage. Additional losses result from processing and marketing of fresh-cut produce. Deterioration of fresh and fresh-cut produce during cold storage can be prevented, or at least diminished. Major problems of fresh-cut products are physiological deterioration, browning and microbial decay at the cut surfaces. We are using several natural products and antioxidants such as methyl jasmonate, amino acids, organic acids, and calcium salts and chelates to alleviate temperature stress and to inhibit enzymatic browning and texture deterioration. This results in a slowdown of microbial growth as well as decreasing the rate of physiological deterioration of cold temperature-sensitive produce. Texture is a critical quality factor for fresh fruits
and vegetables because it relates to consumer acceptability, microbial contamination, and senescence. Most existing instrumental texture measurements were developed for intact fruits or vegetables and are not readily adaptable to fresh-cut sliced or diced products, so new methods must be developed. The changes in texture of fresh-cut produce in response to preparation and storage are not well documented. We are investigating the mechanical properties that change after a fruit or vegetable is cut and stored and how those changes relate to sensory assessments of quality and consumer acceptability. Based on changes in those characteristics, effective instrumental measurements can be developed for routine inspection and for physiological studies. We are also investigating the impact of changes in volatile aroma compounds during storage on sensory acceptability of fresh-cut fruit. Postharvest losses of fresh produce range from 10 to 50% depending upon commodity and storage facilities.
Further losses result from fresh-cut processing and marketing where shelf-life of various items will range from three days to three weeks. Extension of shelf-life would be beneficial with some fresh-cut products as would development of methods to allow use of other produce now considered too sensitive for current processing and storage procedures. As an example, the application of natural antioxidants could open up a market for fresh-cut fruit slices allowing development of new value-added products. One specific problem area being addressed is the prevention of tissue browning that detracts from appearance and reduces market value of fresh-cut produce. Microbial growth on fresh and fresh-cut produce not only affects quality, but also reduces shelf-life of the products. Better methods of preventing browning and reducing decay are urgently needed if postharvest quality of fresh and fresh-cut fruits and vegetables is to be improved. Texture is frequently the quality attribute
limiting the acceptability of fresh fruits and vegetables by the consumer. Cutting and packaging of produce can cause texture breakdown and cause certain quality-related volatiles to either decrease or increase, and these changes may alter consumer acceptability. Because it is such a new industry, there are no established, traditional measurements of quality of fresh-cut products other than sensory (appearance, feel, and taste). Rapid, accurate, and reproducible grading methods will systematize the measurement of quality of these value-added products. The proposed research falls within Component 1 of NP-306 on "Quality Characterization, Preservation, and Enhancement." The project focuses on Category 1 (Fruits, Vegetables, Tree Nuts, and Sugar Crops) and addresses Problem Area 1a, "Definition and Basis for Quality" and Problem Area 1d, "Preservation and/or Enhancement of Quality and Marketability." 2. List the milestones (indicators of progress) from your Project Plan. Milestones are
from a new project essentially approved but not yet certified by OSQR. Year 1 (FY 2004) Better tasting fresh-cut apple cultivars selected. Orange-fleshed fresh-cut honeydew evaluated. Approximately ten GRAS substances evaluated. Texture panel trained. Crispness and crunchiness defined. Year 2-3 (FY 2005-2006) Alternative processing protocols formulated. Food-safe product developed. Alternative sanitation technologies developed. Effective antimicrobial substances and dosages identified. MAP technologies optimized for fresh-cut apples. Sensory and instrumental texture of ~30 commodities measured. Sensory and instrumental measurements made on fresh-cut apple and melon products. Year 4-5 (FY 2007-2008) GRAS treatments optimized. Combination processing and MAP strategies established. Statistical models for hardness, crispness, crunchiness, and toughness in high-moisture products developed and validated. Instrumental texture measurement methods for fresh-cuts recommended. Models proposed
for predicting sweetness, sourness, and acceptability of fresh-cut apple and melon from instrumental measurements. 3. Milestones: A. List the milestones that were scheduled to be addressed in FY 2004. How many milestones did you fully or substantially meet in FY 2004 and indicate which ones were not fully or substantially met, briefly explain why not, and your plans to do so. Heritability patterns of mechanical components of firmness of processing tomatoes was studied. Manuscript is in preparation. Milestones for Year 1 of the new CRIS project, which began July 2004 and replaced CRIS 1275-43440-001-00D, are listed below. Some progress was made on all five prior to the start date of the new project: Better tasting apple cultivars for fresh-cut were tentatively identified. An orange-fleshed fresh-cut honeydew genotype was compared to cantaloupe and green-fleshed honeydew. Screening of several GRAS substances was initiated. Texture panel trained. Crispness and crunchiness were
tentatively defined. B. List the milestones that you expect to address over the next 3 years (FY 2005, 2006, & 2007). What do you expect to accomplish, year by year, over the next 3 years under each milestone? The milestones of next 3 years are listed below with a description of the anticipated outcomes. FY-05 Better tasting apple cultivars for fresh-cut will be evaluated. Additional orange-fleshed fresh-cut honeydew genotypes will be compared to cantaloupe and green-fleshed honeydew. Approximately ten GRAS substances will be evaluated. Crispness and crunchiness definitions will be verified. FY-06 Alternative wash and/or spray treatments for fresh-cut apples will be formulated that will maintain quality and food safety of the product better than that commercially available at present. Alternative sanitation technologies will be developed for fresh-cut melons to enhance microbial quality and potentially shelf stability. Sensory and instrumental texture of ~30 commodities will be
measured to define textural attributes and to recommend measurement methods. FY-07 Alternative wash treatments developed in FY-05 will be refined and recommendations made. Fresh-cut apples will be stored in various controlled atmospheres and packaged using films having different gas exchange rates that will result in modified atmospheres to optimally maintain shelf stability. Effective GRAS substances and dosages will be identified. Instrumental measurements including spectrophotometric and mechanical tests will be compared to sensory evaluations of apple and melon products to improve methods for quality control. 4. What were the most significant accomplishments this past year? A. Single most significant accomplishment during FY 2004 (one per Research Project): GoldRush was found to be a better tasting apple cultivar for fresh cutting than traditional cultivars. The accomplishment was important since repeat sales of fresh-cut apple products is driven by consumer satisfaction with
product taste, which includes its texture, sweetness, acidity, and aroma. Research showed that 'GoldRush' apples have better overall instrumental and sensory quality attributes than many cultivars currently used for fresh-cut processing. Additionally, 'GoldRush' apples can be refrigerated for 12 months in air before processing and for three weeks as the cut product. Once 'GoldRush' becomes more commercially available, it will enable fresh-cut processors to provide a better tasting product, which should enhance fresh-cut apple sales. B. Other significant accomplishment(s). None. C. Significant activities that support special target populations. None. D. Progress Report opportunity to submit additional programmatic information to your Area Office and NPS (optional for all in-house ("D") projects and the projects listed in Appendix A; mandatory for all other subordinate projects). None. 5. Describe the major accomplishments over the life of the project, including their predicted or
actual impact. Since this project is in its first year, no major accomplishments have yet been achieved. 6. What science and/or technologies have been transferred and to whom? When is the science and/or technology likely to become available to the end- user (industry, farmer, other scientists)? What are the constraints, if known, to the adoption and durability of the technology products? Invited presentations were made at the International Fresh-cut Produce Association Annual Meeting and to fruit processors and an equipment manufacturer regarding alternative methods to maintain quality and food safety of fresh-cut fruit products. 7. List your most important publications in the popular press and presentations to organizations and articles written about your work. Poster presentations for fresh-cut processors and/or the general public are as follows: Saftner, R., J. Abbott, and G. Lester. April 2004. Sensory and Analytical Quality Comparisons of Fresh-cut Orange- and Green-fleshed
Honeydews and Orange-fleshed Cantaloupe. Saftner, R., A. Bhagwat, and J. Abbott. April 2004. Sensory, Analytical and Microbial Quality Comparisons of Fresh-cut Apple Slices Processed with Commercial and Experimental Wash Solutions. Abbott, J. and R. Saftner. BARC Public Field Day, June 2004. Fresh-cut Orange-fleshed Honeydews.
Impacts
(N/A)
Publications
- Gonzalez-Aguilar, G.A., Ruiz, S., Zavaleta, R., Wang, C.Y. 2003. Physiological changes in pineapple slices treated with antibrowning agents. Food Science and Technology. May 2004, V. 37. Issue 3, P. 369-376.
- Park, B., Abbott, J.A., Lee, K., Choi, C., Choi, K. 2004. Near-infrared diffuse reflectance for quantitative and qualitative measurement of soluble solids and firmness of delicious and gala apples. Transactions of the ASAE.
- Wang, C.Y. 2003. Maintaining postharvest quality of raspberries with natural volatile compounds. International Journal of Food Science and Technology 2003, 38, 869-875
- Wang, C.Y., Fung, R., Ding, C. 2003. Reducing chilling injury and enhancing transcript levels of heat shock proteins, pr-proteins and alternative oxidase by methyl jasmonate and methyl salicylate in tomatoes and peppers. Meeting Abstract. 2003. V. 38. P. 860.
- Zheng, Y., Wang, C.Y., Wang, S.Y., Zheng, W. 2003. Effect of high oxygen atmospheres on blueberry phenolics, anthocyanins, and antioxidant capacity. Journal of Agricultural and Food Chemistry. Vol. 51, No. 24, 7162-7169
- Fung, R.W., Wang, C.Y., Smith, D.L., Gross, K.C., Tian, M. Treatments with methyl salicylate and methyl jasmonate increase chilling tolerance and expression levels of alternative oxidase transcript in bell peppers. Hortscience. 2003. V. 38. P. 860.
- Gonzalez-Aguilar, G.A., Buta, J.G., Wang, C.Y. 2003. Methyl jasmonate reduces decay and maintains postharvest quality of papaya 'sunrise'. Postharvest International Symposium Proceedings. V. 28. P. 371-370.
- Wang, C.Y. Quality of tomato slices freshly cut from fruit treated with methyl jasmonate. Meeting Abstract. 2004. V. 39. P. 817.
- Abbott, J.A. Sensory and instrumental measurements of texture of fruits and vegetables. Meeting Abstract. HortScience. 2004. V. 39. P. 830
- Abbott, J.A., Saftner, R.A., Gross, K.C., Vinyard, B.T., Janick, J. 2004. Consumer evaluation and quality measurement of fresh-cut slices of 'fuji', 'golden delicious', 'goldrush', and 'granny smith' apples. Postharvest Biology and Technology. v. 33(2). p. 127-140.
- Ding, C., Wang, C.Y. 2003. The dual effects of methyl salicylate on ripening and expression of ethylene biosynthesis genes in tomato fruit. Plant Science. 164 (2003) 589-596
- Wang, C.Y., Fung, R.W., Smith, D.L., Gross, K.C., Tao, Y., Tian, M. Correlation of increased alternative oxidase gene expression with reduced chilling injury in cold-stored tomatoes (lycopersicon esculentum). Meeting Abstract. 2004. V. 39. P. 806.
- Saftner, R.A., Abbott, J.A., Lester, G.E. Sensory and analytical analyses of fruit quality constituents of fresh-cut orange- and green-fleshed honeydews and orange-fleshed cantaloupe. Hortscience. 2004. V. 39. P. 806.
- Saftner, R.A., Bai, J., Abbott, J.A., Lee, Y. Sanitary dips with calcium propionate, calcium chloride, or a calcium amino acid chelate maintain quality and shelf stability of honeydew chunks. Postharvest Biology and Technology. 2003. V. 29. P. 257-269.
- Abbott, J.A., Stommel, J.R., Camp, M.J. Heritability patterns of elastic and viscoelastic components of tomato firmness derived from intra- and interspecific genetic backgrounds. Meeting Abstract. HortScience. 2004. V. 39. P. 812.
- Fung, R.W., Wang, C.Y., Smith, D.L., Gross, K.C., Tian, M. 2003. Mesa and meja increase steady-state transcript levels of alternative oxidase and resistance against chilling injury in sweet peppers (capsicum annuum l.). Plant Science. 166(2004) 711-719
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Progress 10/01/02 to 09/30/03
Outputs
1. What major problem or issue is being resolved and how are you resolving it? Major postharvest losses of fresh produce occur during cold storage. Additional losses result from processing and marketing of fresh cut produce. Deterioration of fresh and fresh cut produce during cold storage can be prevented, or at least diminished. Major problems of fresh cut products are physiological deterioration, browning and microbial decay at the cut surfaces. We are using several natural products and antioxidants such as methyl jasmonate, amino acids, organic acids, and calcium salts and chelates to alleviate temperature stress and to inhibit enzymatic browning and texture deterioration. This results in a slowdown of microbial growth as well as decreasing the rate of physiological deterioration of cold temperature sensitive produce. Texture is a critical quality factor for fresh fruits and vegetables because it relates to consumer acceptability, microbial contamination, and
senescence. Most existing instrumental texture measurements were developed for intact fruits or vegetables and are not readily adaptable to fresh-cut sliced or diced products, so new methods must be developed. The changes in texture of fresh-cut produce in response to preparation and storage are not well documented. We are investigating the mechanical properties that change after a fruit or vegetable is cut and stored and how those changes relate to sensory assessments of quality and consumer acceptability. Based on changes in those characteristics, effective instrumental measurements can be developed for routine inspection and for physiological studies. We are also investigating the impact of changes in volatile aroma compounds during storage on sensory acceptability of fresh-cut fruit. 2. How serious is the problem? Why does it matter? Postharvest losses of fresh produce range from 10 to 50% depending upon commodity and storage facilities. Further losses result from fresh cut
processing and marketing where shelf life of various items will range from three days to three weeks. Extension of shelf life would be beneficial with some fresh cut products as would development of methods to allow use of other produce now considered too sensitive for current processing and storage procedures. As an example, the application of natural antioxidants could open up a market for fresh-cut fruit slices allowing development of new value-added products. One specific problem area being addressed is the prevention of tissue browning that detracts from appearance and reduces market value of fresh cut produce. Microbial growth on fresh and fresh cut produce not only affects quality, but also reduces shelf life of the products. Better methods of preventing browning and reducing decay are urgently needed if postharvest quality of fresh and fresh cut fruits and vegetables is to be improved. Texture is frequently the quality attribute limiting the acceptability of fresh fruits
and vegetables by the consumer. Cutting and packaging of produce can cause texture breakdown and cause certain quality-related volatiles to either decrease or increase, and these changes may alter consumer acceptability. Because it is such a new industry, there are no established, traditional measurements of quality of fresh-cut products other than sensory (appearance, feel, and taste). Rapid, accurate, and reproducible grading methods will systematize the measurement of quality of these value-added products. 3. How does it relate to the National Program(s) and National Program Component(s) to which it has been assigned? National Program 306, Quality Utilization of Agricultural Products (100%). Our research uses combinations of naturally occurring compounds, as well as selected physical treatments, to increase the resistance of plant tissues to physiological deterioration, microbial decay and browning resulting from fresh cut processing. New fresh cut products should result from
these research approaches on fruits and vegetables not previously usable because of their susceptibility to the above mentioned deleterious processes. Better grading technology will provide an expanded basis for marketing by quality, with appropriate pricing for high-quality products. Better quantification of textural changes will also enhance studies of the physiological mechanisms and genetic regulation of senescence. 4. What were the most significant accomplishments this past year? A. Single Most Significant Accomplishment during FY 2003: Intact and fresh-cut produce deteriorate very rapidly because of physiological breakdown and pathological decay. Beltsville researchers in the Produce Quality and Safety Laboratory investigated methods to delay senescence and reduce decay of fresh and fresh-cut fruits and vegetables. Several naturally-occurring volatile compounds, such as methyl jasmonate, methyl salicylate, allyl isothiocyanate, tea tree oil, absolute ethyl alcohol,
1-propanol, isopropyl alcohol, and vinegar, were found to be effective in reducing mold growth and maintaining quality of papayas and fresh-cut kiwifruit. These results are of interest to other postharvest researchers and have potential benefit to the produce industry. B. Other significant accomplishments: Fresh-cut apple slices are an important emerging fresh-cut fruit product, but maintaining quality and food safety of packaged apple slices during cold storage is still under development. Beltsville scientists in the Produce Quality and Safety Laboratory developed several relatively low- cost, all-natural solutions that maintain the quality and food safety of packaged apple slices for 3 weeks while also maintaining consumer acceptability. We found that such solutions should not be reused on multiple batches of sliced apples as they lose their anti-microbial properties and that packaging apple slices in lidded containers or bags prepared from certain types of commonly used plastic
films without and with micro-perforations also reduces the risk of decay development during cold storage. Results are expected to aid apple growers and processors develop a consistent high quality and food safe product that is packaged correctly for shipping and retail marketing. Beta-carotene enhances nutritional value of fruits and vegetables and is a desirable attribute and gives an orange color. Beltsville Area scientists in the PQSL and the Vegetable Laboratory compared cherry tomato breeding lines with increased beta-carotene to commercial red cherry tomato cultivars by sensory evaluations (consumer panel). Panelists preferred the appearance of red to orange tomatoes when viewed under normal lighting, but scored most eating quality attributes from red and orange tomatoes similarly whether they could discern the color or not, despite higher concentrations of sugars and certain aroma volatiles in the orange fruit; but, importantly, high beta-carotene lines were scored firmer and
crunchier than commercial red cultivars. Results will aid researchers in developing more nutritive tomato lines and will alert marketers that consumer education may be needed to gain acceptance of orange-fruited, high beta-carotene tomatoes. C. None. D. None. 5. Describe the major accomplishments over the life of the project, including their predicted or actual impact. Found methyl jasmonate, a naturally occurring substance, to be effective in reducing deterioration and inhibiting microbial decay of several fresh- cut fruits and vegetables. These findings have potential to benefit both the fresh produce industry and the fresh-cut produce industry. Certain calcium salts and calcium-binding compounds (chelates) protected fresh-cut melon products from color, taste, or textural changes and more than doubled the shelf-life of fresh-cut products even under abusive temperature storage. These treatments provide melon processors with a method to extend shelf-life of melon products and
has intensified efforts to use calcium chelates as a pre-harvest treatment to extend postharvest life of intact and fresh-cut melon. Treatment with 1-methylcyclopropene (MCP), an inhibitor of ethylene (a fruit ripening hormone) action, is an effective alternative to use of controlled atmosphere (CA) storage for maintaining postharvest quality and shelf-life of intact apples during storage and handling. Importantly, it was also found that the use of MCP treatment, which is becoming widely used commercially, is not as effective as CA storage at inhibiting postharvest decays in intact apples. These results contributed to the commercial use of MCP on US-grown apples to maintain fruit quality during storage and handling, and has alerted the apple industry to combine an antifungal treatment with the MCP treatment if necessary to control decay during storage of MCP-treated fruit. Firmness characteristics of fruits and vegetables determine not only their consumer acceptability but also
their ability to withstand storage, handling, and preparation as fresh-cut products. However standardized texture measurement methods are lacking. Beltsville Area scientists in the Produce Quality and Safety Laboratory developed mathematical models for force relaxation characteristics of tomato flesh and found differences in relaxation behavior of whole fruit among genetically- altered lines of processing tomatoes (collaboration with Beltsville Vegetable Laboratory) but not in altered round-type tomatoes. Changes in firmness and force relaxation characteristics of fresh-cut tomato slices during storage differed between the outer wall and core of apples, and this depended on the ripeness of the fruit at harvest. The texture measurements have been used to select elite breeding lines and to study mechanisms of softening, and they will be useful to engineers developing handling and quality measurement systems. 6. What do you expect to accomplish, year by year, over the next 3 years?
During FY 2004, ARS will determine the optimization of a postharvest system for fresh-cut apple slices with more detailed attention to packaging effects on instrumental and sensory quality and food safety of the fresh-cut product at temperatures and atmospheres which the product may experience during shipping and marketing. Establish the physical and chemical factors that aid survival of human pathogens on apple slices and in solutions for processing apple slices, and develop washing strategies that optimally maintain the quality and food safety of packaged apple slices. ARS will determine fundamental studies of sensory perception of crispness and crunchiness in fresh produce and the relationship between mechanical properties and sensory texture attributes. ARS will determine the effectiveness of natural volatile compounds on maintaining quality of raspberries. During FY 2005, ARS will identify apple varieties best suited for fresh- cut processing into slices. Determine if human
pathogens can penetrate through micro-perforated bags and contaminate apple slices therein. Develop an integrated strategy of natural chemical and physical treatments to maintain quality and shelf-life of fresh-cut melon chunks with emphasis on anti-microbial treatments such as ozone gas, biocontrol agents and hot water heat treatments. During FY 2006, determine the instrumental and sensory quality and shelf- life of fresh-cut, orange-fleshed honeydew chunks relative to green- fleshed honeydew and cantaloupe chunks. Apply fresh-cut apple slice and melon chunk technologies to other fresh-cut products. Determine if alternative oxidase is involved in ameliorating chilling injury and if its expression is enhanced by methyl jasmonate. 7. What science and/or technologies have been transferred and to whom? When is the science and/or technology likely to become available to the end- user (industry, farmer, other scientists)? What are the constraints, if known, to the adoption and
durability of the technology products? ARS scientists created a completely new and substantially improved Agriculture Handbook 66 entitled "The Commercial Storage of Fruits, Vegetables, and Florist and Nursery Crops" which is posted on the Internet for transfer of technology of postharvest techniques to general public. Transferred wash solution technology for maintaining the quality, shelf- life and food safety of fresh-cut apple slices to a grower organization for their members' use in fresh-cut apple processing. Shared information and advised a company on methods of treatment and analysis and benefits of 1-methylcyclopropene for use on intact and fresh-cut products to include intact and fresh-cut tomato slices and intact and fresh-cut lettuce and spinach. Transferred technology for analyzing and scrubbing ethylene from air samples and evaluating effects of ethylene on fresh produce to a commercial firm.
Impacts
(N/A)
Publications
- Bai, J., Saftner, R., Watada, A. Characteristics of fresh-cut honeydew (Cucumis Xmelo L.) available to processors in winter and summer and its quality maintenance by modified atmosphere packaging. Journal of Postharvest Biology and Technology. 2003. v. 28. p. 349-359.
- Ding, C.K., Chachin, K., Ueda, Y., Imahori, Y., Wang, C.Y. Modified atmosphere packaging maintains postharvest quality of loquat fruit. Postharvest Biology and Technology. 2002. v. 24. p. 341-348.
- Fung, R., Wang, C., Smith, D., Gross, K., and Tian, M. Correlation of alternative oxidase gene expression with chilling injury in sweet peppers (Capsicum annuum L.) BARC 2003 Poster Day Abstract. Abstract No. 46.
- Gonzalez-Aguilar, G. A., Buta, J. G., Wang, C. Y. Methyl jasmonate reduces decay and maintains postharvest quality of papaya 'Sunrise'. Postharvest Biology and Technology. 2003. v. 28. p. 361-370.
- Saftner, R. A., Abbott, J. A., Barden, C. L., Conway, W. S. Postharvest instrumental and sensory quality characteristics of 'Gala' apples in response to a prestorage heat, controlled atmosphere, and air storage. Journal of American Society for Horticultural Science. 2002. v. 127. p. 1006-1012.
- Abbott, J.A., Buta, J.G. Effect of antibrowning treatment on color and firmness of fresh-cut pears. Journal of Food Quality. 2002. v. 25. p. 333- 341.
- Saftner, R., Abbott, J., Conway, W., Barden, C. Effects of 1- methylcyclopropene and heat treatments on ripening and postharvest decay in 'Golden Delicious' apples. Journal of American Society for Horticultural Science. 2003. v. 128. p. 120-127.
- Smith, D.L., J.A. Abbott, and K.C. Gross. Down-regulation of tomato ss- galactosidase results in decreased tomato fruit softening. Plant Physiology. 2002. v. 129. p.1755-1762.
- Wang, C. Y. Leafy, floral and succulent vegetables. Bartz, J. A., Brecht, J. K. editors. Marcel Dekker, Inc., New York, NY. Postharvest Physiology and Pathology of Vegetables. 2003. p. 599-623.
- Wang, C. Y., Buta, J. G. Maintaining quality of fresh-cut kiwifruit with volatile compounds. Postharvest Biology and Technology. 2003. v. 28. p.181- 186.
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Progress 10/01/01 to 09/30/02
Outputs
1. What major problem or issue is being resolved and how are you resolving it? Major postharvest losses of fresh produce occur during cold storage. Additional losses result from processing and marketing of fresh-cut produce. Deterioration of fresh and fresh-cut produce during cold storage can be prevented, or at least diminished. Major problems of fresh cut products are physiological deterioration, browning and microbial decay at the cut surfaces. We are using several natural products and antioxidants such as methyl jasmonate, amino acids, organic acids, and calcium salts and chelates to alleviate temperature stress and to inhibit enzymatic browning and texture deterioration. This results in a slowdown of microbial growth as well as decrease in the rate of physiological deterioration of cold temperature-sensitive produce. Texture is a critical quality factor for fresh fruits and vegetables because it relates to consumer acceptability, microbial contamination, and
senescence. Most existing instrumental texture measurements were developed for intact fruits or vegetables and are not readily adaptable to fresh-cut sliced or diced products, so new methods must be developed. The changes in texture of fresh-cut produce in response to preparation and storage are not well documented. We are investigating the mechanical properties that change after a fruit or vegetable is cut and stored and how those changes relate to sensory assessments of quality and consumer acceptability. Based on changes in those characteristics, effective instrumental measurements can be developed for routine inspection and for physiological studies. We are also investigating the impact of changes in volatile aroma compounds during storage on sensory acceptability of fresh-cut fruit. 2. How serious is the problem? Why does it matter? Postharvest losses of fresh produce range from 10 to 50% depending upon commodity and storage facilities. Further losses result from fresh-cut
processing and marketing where shelf-life of various items will range from 3 days to 3 weeks. Extension of shelf-life would be beneficial with some fresh-cut products, as would development of methods to allow use of other produce now considered too sensitive for current processing and storage procedures. As an example, the application of natural antioxidants could open up a market for fresh-cut fruit slices allowing development of new value-added products. One specific problem area being addressed is the prevention of tissue browning that detracts from appearance and reduces market value of fresh-cut produce. Microbial growth on fresh and fresh-cut produce not only affects quality, but also reduces product shelf-life. Better methods of preventing browning and reducing decay are urgently needed if postharvest quality of fresh and fresh-cut fruits and vegetables is to be improved. Texture is frequently the quality attribute limiting acceptability of fresh fruits and vegetables by
the consumer. Cutting and packaging of produce can cause texture breakdown and changes in levels of certain quality-related volatiles, and these changes may alter consumer acceptability. Because it is such a new industry, there are no established, traditional measurements of quality of fresh-cut products other than sensory (appearance, feel, and taste). Rapid, accurate, and reproducible grading methods will systematize the measurement of quality of these value-added products. 3. How does it relate to the national Program(s) and National Program Component(s) to which it has been assigned? National Program 306, Quality & Utilization of Agricultural Products (100%). Our research uses combinations of naturally occurring compounds, as well as selected physical treatments, to increase the resistance of plant tissues to physiological deterioration, microbial decay and browning resulting from fresh-cut processing. New fresh-cut products should result from these research approaches on
fruits and vegetables not previously viable for fresh-cut processing because of their susceptibility to the above-mentioned deleterious processes. Better grading technology will provide an expanded basis for marketing by quality, with appropriate pricing for high-quality products. Better quantification of textural changes will also enhance studies of the physiological mechanisms and genetic regulation of senescence. 4. What was your most significant accomplishment this past year? A. Single Most Significant Accomplishment during FY 2002: Intact and fresh-cut produce deteriorate very rapidly because of physiological breakdown and pathological decay. Scientists of the Produce Quality and Safety Laboratory at Beltsville, MD have been investigating methods to delay senescence and reduce decay of fresh and fresh-cut fruits and vegetables. Several natural volatiles such as methyl jasmonate, methyl salicylate, allyl isothiocyanate, tea tree oil, absolute ethyl alcohol, 1-propanol,
isopropyl alcohol, and vinegar were found to be effective in reducing mold growth and maintaining quality of tomato slices, strawberries, blueberries, raspberries, and blackberries. These results have a solid potential to benefit the fresh produce industry B. Other Significant Accomplishment(s), if any: Fresh-cut apple slices are an emerging, highly-desired fresh-cut product for retail markets. Scientists of the Produce Quality and Safety Laboratory at Beltsville MD, evaluated a number of all-natural solutions and films for packaging apple slices prepared from both popular and new cultivars. Treatment with an all-natural solution was identified that maintains excellent quality for 3 weeks without affecting overall consumer acceptability of the fresh-cut product. This treatment protects apple slices from decay, reduces packaging requirements and offers an alternative to an expensive antibrowning solution now used on fresh-cut apple slices. C. Significant Activities that Support
Special Target Populations: None D. Progress Report: None 5. Describe your major accomplishments over the life of the project, including their predicted or actual impact? ARS scientists at Beltsville found that methyl jasmonate, a naturally occurring substance, reduced deterioration and inhibited microbial decay of several fresh-cut fruits and vegetables. Certain calcium salts and chelates protected fresh-cut melon products from color, taste, or textural changes and more than doubled shelf-life of fresh-cut products, even under abusive temperature storage. The treatment provides melon processors with a method to extend shelf-life of melon products and has intensified efforts to use calcium chelates as a preharvest treatment. Treatment with 1-methylcyclopropene (MCP), an inhibitor of ethylene action, is an effective alternative to controlled atmosphere storage for maintaining postharvest quality and shelf-life of intact apples during storage and handling. However, the MCP treatment
was not as effective as controlled atmosphere storage at inhibiting postharvest decays in intact apples. The results contributed to the commercial use of MCP on US-grown apples to maintain fruit quality during storage and handling, and has alerted the apple industry to combine an antifungal treatment with the MCP treatment to control decay during storage of MCP-treated fruit. 6. What do you expect to accomplish, year by year, over the next 3 years? During FY 2003, ARS will determine the respiration and ethylene production rates of intact and fresh-cut vegetables for which such information is lacking. Continue development of an expert texture analysis panel. Relate mechanical properties to sensory attributes of fruits and vegetables to develop better definitions and measurement methods for crispness and crunchiness, which are critical textural characteristics for many fresh fruits and vegetables. Initiate development of a postharvest system for fresh-cut apple slices with
consideration of cultivar selection, physiology, pathology, and sensory quality. Conduct exploratory experiments on the feasibility of postprocessing or in-package treatment of fresh-cut melon products with chlorine dioxide as a gaseous sanitization procedure. Conduct experiments to determine the effectiveness of using natural volatile compounds on maintaining quality of fresh-cut kiwifruit. During FY 2004, ARS will continue optimization of a postharvest system for fresh-cut apple slices with more detailed attention to packaging and sensory evaluations. Evaluate chlorine dioxide treatment on fresh-cut fruits and vegetables as an antimicrobial method to extend the shelf-life of fresh-cut produce. Continue to compare instrumental and sensory measurements to develop improved quality measurement methods. Evaluate the effects of pre- and postharvest factors on quality of fresh-cut melon, tomato, cucurbits, leafy vegetables, and other produce by instrumental and sensory measurements.
Evaluate the effect of high oxygen treatments on sugars, organic acids, volatile production, and shelf-life of strawberries and other produce. During FY 2005, ARS will develop an integrated strategy of natural chemical and physical treatments to maintain quality and extend shelf- life of fresh cut melon chunks. Initiate experiments to adapt this technology to other fresh-cut products. Continue to compare instrumental and sensory measurements to optimize quality measurement methods. Evaluate the effects of pre-harvest and postharvest operations on quality of intact and fresh-cut produce by instrumental and sensory measurements. Investigate the mechanism of chilling injury reduction by methyl jasmonate. 7. What technologies have been transferred and to whom? When is the technology likely to become available to the end user (industry, farmer other scientist)? What are the constraints, if known, to the adoption durability of the technology? Numerous inquiries were received on the use
of methyl jasmonate as a stress relief for cold storage of fruits and vegetables. Many of our reprints and publications on methyl jasmonate were sent out and distributed to various growers, shippers, and companies handling fresh and fresh-cut produce. We transferred technology for using ethylene in the presence of MCP to optimize MCP treatment of apples to the Washington Tree Fruit Research Commission. Shared information with Brentwood Plastics on film permeability requirements needed for fresh-cut apple slices. Transferred technology of using calcium amino acid chelates to maintain the quality and extend the shelf-life of fresh-cut melon chunks to Albion Laboratories.
Impacts
(N/A)
Publications
- 1. Bai, J., Saftner, R.A., Watada, A.E., Lee, Y.S. Modified atmosphere maintains quality of fresh-cut cantaloupe (Cucumis melo L.). Journal of Food Science. 2001. v. 66, p. 1207-1211.
- 2. Ding, C.K., Wang, C.Y., Gross, K.C., Smith, D.L. Reduction of chilling injury and transcript accumulation of heat shock proteins in tomato fruit by methyl jasmonate and methyl salicylate. Plant Science. 2001. v. 161. p. 1153-1159.
- 3. Ding, C.K., Wang, C.Y., Gross, K.C., Smith, D.L. Jasmonate and salicylate induce the expression of pathogenesis-related protein genes and increase resistance to chilling injury in tomato fruit. Planta. 2002. v. 214. p. 895-901.
- 4. Fung, R.W.M., Zheng, Y., Tian, M., Wang, C.Y. Effects of methyl jasmonate and superatmospheric oxygen levels on alternative oxidase in low temperature stored green pepper (Capsicum annum L.) and zucchini squash (Cucurbita pepo L.). BARC Poster Day Abstract. 2002. p. 39.
- 5. Gonzalez-Aguilar, G.A., Wang, C.Y., Buta, J.G. Inhibition of browning and decay of fresh-cut radishes by natural compounds and their derivatives. Food Science and Technology. 2001. v. 34. p. 324-328.
- 6. Gonzalez-Aguilar, G.A., Wang, C.Y., Buta, J,G., Krizek, D.T. Use of UV- C irradiation to prevent decay and maintain postharvest quality of ripe 'Tommy Atkins' mangos. International Journal of Food Science and Technology. 2001. v. 36. p. 767-773.
- 7. Gonzalez-Aguilar, G.A., Buta, J.G., Wang, C.Y. Methyl jasmonate reduces chilling injury and enhances color development of 'Kent' mangoes. Journal of Science of Food and Agriculture 2001. v. 81. p. 1244-1249.
- 8. Lu, T., Abbott, J.A. Firmness and force relaxation characteristics of tomatoes stored intact or as slices. Postharvest Biology and Technology 2002. v. 24. p. 59-68.
- 9. Park, B., Abbott, J.A., Lee, K.J., Choi, C.H., Choi, K.H. Near-infrared Spectroscopy to Predict Soluble Solids and Firmness in Apples. American Society for Agricultural Engineers. 2002. Paper No. 02-3066. p. 1-21.
- 10. Wang, C.Y., Bowen, J.H., Weir, I.E., Allan, A.C., Ferguson, I.B. Heat- induced protection against death of suspension-cultured apple fruit cells exposed to low temperature. Plant, Cell and Environment. 2001. v. 24. p. 1199-1208.
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