2007 Annual Report
1a.Objectives (from AD-416)
Develop novel or alternative postharvest systems to maintain quality of intact and fresh-cut fruits and vegetables with consideration of cultivar selection, physical and sensory characteristics, physiology, pathology, food safety, and produce responses to non-chemical and GRAS (Generally Regarded As Safe) treatments. Apple, melon, pepper, squash, tomato, and potentially other products will be evaluated.
Develop new or improved instrumental quality measurements after elucidating the relationships between physical and sensory characteristics of intact and fresh-cut products.
1b.Approach (from AD-416)
The approaches used in this project to reach our objectives will be based on developing and integrating different technologies to achieve the desired levels of quality, stability and safety. We will integrate technologies such as cultivar selection, postharvest non-chemical and chemical treatments to prevent or decrease microbial contamination, fresh-cut processing methods, biocontrol methods, modified atmosphere packaging, and different storage regimes. Microbial assays, sensory evaluations, and a variety of instrumental methodologies will be used or developed to measure changes in produce quality and safety after treatment. Specifically, alternative processing and packaging technologies to improve shelf stability and food safety of fresh-cut products will be combined with the selection of optimal cultivars. Methods for maintaining quality of intact produce with GRAS (generally regarded as safe) substances will be optimized. Instrumental methods that better predict overall quality or specific sensory characteristics will be developed following study of the relationships between physical and sensory properties.
Postharvest treatment strategy for fresh-cut apple slices.
Commercial processing formulations for fresh-cut produce have been developed that maintain the instrumental and sensory quality, but not the microbial quality and food safety of the fresh-cuts. A postharvest strategy developed in 2005 to maintain the quality, shelf stability and food safety of fresh-cut apple products was optimized. The strategy includes a brief (2-3 minute) preprocessing heat treatment to control fungal pathogens and spoilage yeasts, and a processing treatment formulation that inhibits or eliminates, depending on concentration and microbe, spoilage bacteria and five bacterial human pathogens (exogenously applied to freshly processed slices) on packaged apple slices during storage. A Confidentiality Agreement has been signed between ARS and Manntrose-Haeuser Co. to discuss patenting and licensing options and what additional research needs to be done to gain FDA approval for use of the new technology on lightly processed fruits and vegetables. This research was one of the FY 2007 milestones (Optimize alternative wash treatments developed in FY-05 and make recommendations). This research is under National Program 306, Component I, Problem Areas 1a, 1c and 1d; and ARS Strategic Plan Goal 2, Performance Measure 2.1.2 (Goal 2, PM 2.1.2.) and Goal 4, PM 4.1.1.
Efficacy of GRAS treatments in fresh and fresh-cut produce.
Several natural antimicrobial compounds derived from essential oils of plants were investigated for their efficacies in inhibiting decay and extending shelf life of strawberries. The severity of decay in strawberries stored at 10 ºC was significantly reduced by treatment with thymol, menthol, or eugenol. All of these three natural antimicrobial compounds extended shelf life of strawberries as compared to the control. Treated fruit also maintained better quality with higher levels of sugars, organic acids, phenolics, anthocyanins, flavonoids, and oxygen radical absorbance capacity (ORAC) than the untreated fruits. Higher radical scavenging capacities were found against DPPH• and HO• in all treated fruit, particularly in berries treated with thymol, compared to those in control groups. Extracts from all treated fruit exhibited significantly stronger inhibition on HT-29 cell proliferation than those from the control fruit. These data provide evidence that in addition to possessing antimicrobial activity, the essential oils also increase free radical scavenging capacity and antiproliferative activity in fruit and, in turn, enhance the resistance of fruit tissues to deterioration and spoilage. This research is under National Program 306, Component I, Problem Areas 1a, 1c and 1d; and ARS Strategic Plan Goal 2, Performance Measure 2.1.2 (Goal 2, PM 2.1.2.).
Characterization of quality and shelf stability of a new orange-fleshed melon hybrid.
The quality of fresh-cut melon products available to processors in winter and summer differs and shelf-life is less than or equal to 1 week. The instrumental and sensory quality and shelf stability of fresh-cut chunks from an ultra firm, orange-fleshed hybrid melon developed by a U.S. Vegetable Seed Co. for the fresh-cut market during the winter was evaluated and compared to fresh-cut cantaloupe and honeydew chunks available to processors in winter. Fresh-cut chunks from hybrid melons stored 5 weeks postharvest generally had better instrumental and sensory quality, longer shelf-life and a higher nutritional content than chunks processed from cantaloupes and honeydews available to processors in winter. Fruit from ultra firm hybrid melon genotypes will improve the quality and shelf stability of fresh-cut melon products available during the winter. This research was one of the FY 2007 milestones (Evaluate new orange-fleshed melon hybrids as a potential alternative to cantaloupe for maintaining year-round analytical and sensory quality of fresh-cut melon products). This research is under National Program 306, Component I, Problem Areas 1a, 1c and 1d; and ARS Strategic Plan Goal 2, Performance Measure 2.1.2 (Goal 2, PM 2.1.2.).
5.Significant Activities that Support Special Target Populations
|Number of non-peer reviewed presentations and proceedings||4|
Ayala-Zavala, J., Wang, C.Y., Wang, S.Y., Gonzalez-Aguilar, G.A. 2007. Response of strawberry fruit to high oxygen treatment. Food Technology and Biotechnology. 45:166-173.
Chanjirakul, K., Wang, S.Y., Wang, C.Y., Siriphanich, J. 2007. Natural volatile treatments increase free radical scavenging capacity of strawberries and blackberries. Journal of the Science of Food and Agriculture. 87:1463-1472.
Wang, C.Y., Erkan, M. 2006. Modified and controlled atmosphere storage of tropical and subtropical fruits. Stewart Postharvest Review. 5: Chapter 4.
Lester, G.E., Saftner, R.A., Hodges, D. 2007. Market quality attributes of orange-fleshed, non-netted honeydew melon genotypes as influenced by growing season, storage duration, and temperature. HortTechnology. 17:346-352.
Saftner, R.A., Abbott, J.A., Lester, G.E., Vinyard, B.T. 2006. Sensory and analytical comparisons of orange-fleshed honeydew to cantaloupe and green-fleshed honeydew for fresh-cut chunks. Postharvest Biology and Technology. 42:150-160.
Saftner, R.A., Luo, Y., Mcevoy, J.L., Abbott, J.A., Vinyard, B.T. 2007. Analytical quality characteristics of fresh-cut watermelon slices from non-treated and 1-methylcyclopropene- and/or ethylene-treated whole fruit. Postharvest Biology and Technology. 4(1):71-79.
Wang, C.Y. 2006. Biochemical basis of the effects of modified and controlled atmospheres. Stewart Postharvest Review. 5: Chapter 8.
Zheng, Y., Wang, C.Y. 2007. Effect of high oxygen atmospheres on quality of fruits and vegetables. Stewart Postharvest Review. 6(2):1-8.
Zheng, Y., Wang, S.Y., Wang, C.Y., Zheng, W. 2006. Changes in strawberry phenolics, anthocyanins, and antioxidant capacity in response to high oxygen treatments. Food Science and Biotechnology. 40:49-57.