2012 Annual Report
2. Relate chemical composition to sensory flavor and pathogen resistance data from Objective 1 to determine which compounds are important for flavor or have anti-microbial properties. a) Modeling for quality evaluation. b) Modeling for shelf life as limited by decay and identify natural compounds with antimicrobial activity.
3. Develop pre- and postharvest treatment protocols for reducing specific decay pathogens using sanitizers, antimicrobials, such as plant (including citrus) essential oils, with or without coatings and/or other surface treatments and storage atmospheres to minimize postharvest losses and maximize shelf life of the of citrus, tomato, berries and select tropicals for both intact and fresh-cut products. a) Pre-harvest treatments to reduce postharvest pathogens and to enhance postharvest quality. b) Postharvest treatments to prevent decay and transference of fruit surface microbes.
Objective 2a: Gas chromatography and olfactometry (GC-O) of ‘Fallglo’ tangerines showed that 32% of the identified volatile compounds with aroma activity could be detected by human subjects but not by the instrument detector. Two new aroma-active compounds were found (methional and 1-nonen-3-one), not previously reported in tangerines. A method for detecting DNA from Candidatus Liberibacter asiaticus, the putative bacterium responsible for HLB disease, in orange juice was developed using quantitative polymerase chain reaction. Gene expression of linalool, a potential antimicrobial compound in strawberry fruit, was studied.
Objective 2b: Studies are underway that measure plant chemical responses to pathogen attack. Citrus leaves affected by HLB or canker diseases produce different compounds than healthy leaves, hence modifying the microbial population biology on the leaf surface. A soil fungus, Trichoderma viridae, is being studied for its antimicrobial qualities and chemicals are being extracted, identified and tested against Xanthomonas citri, subsp. Citri (Xcc), the bacterium causing citrus canker.
Objective 3a: Field applications of a wax formulation on grapefruit trees reduced canker inoculum in the field, and resulted in increased fruit pack out. Field applications of potassium sorbate and “Tree-wash”, a commercial sanitizer (TW) were performed on blueberries during fruit development and before harvest. The TW reduced postharvest decay and increased sweetness but it was not consistent for all varieties.
Objective 3b: A combination of field application of wax formulations and postharvest sanitizers such as peroxyacetic acid significantly reduced canker on fruit destined for out-of-State shipping. Fruit inoculated with Xcc had their bacterial count significantly reduced after placing slow release ClO2 sachets (Curoxin®) inside the container of citrus. Curoxin® also extended strawberry and blueberry shelf life by reducing decay and water loss, and maintaining firmness, color and overall quality. Clamshell packaging was developed that extends cherry and blueberry shelf life. Curoxin® was added to soy protein coating and eliminated E. coli from inoculated blueberries.
Du, X., Plotto, A., Baldwin, E.A., Rouseff, R. 2011. Evaluation of volatiles from two subtropical strawberry cultivars using GC-olfactometry, GC-MS odor activity values, and sensory analysis. Journal of Agricultural and Food Chemistry. 59:12569-12577.
Miyazaki, T., Plotto, A., Baldwin, E.A., Reyes-De-Corcuera, J., Gmitter, F. 2012. Aroma characterization of tangerine hybrids by gas-chromatography-olfactometry and sensory evaluation. Journal of the Science of Food and Agriculture. 92:727-735.
House, L.A., Gao, Z., Spreen, T.H., Gmitter, F.G., Valim, M.F., Plotto, A., Baldwin, E.A. 2011. Consumer preference for mandarins: Implications of a sensory analysis. Agribusiness: An International Journal. 27(4):450-464.
Whitaker, V., Chandler, C., Santos, B., Peres, N., Nunes, C., Plotto, A., Sims, C. 2012. Winterstar™ (‘FL 05-107’) strawberry. HortScience. 47:296-298.
Zhang, D., Yu, B., Bai, J., Qian, M., Shu, Q., Su, J., Teng, Y. 2012. Effects of high temperatures on UV-B/visible irradiation induced postharvest anthocyanin accumulation in ‘Yunhongli No. 1’ (Pyrus pyrifolia Nakai) pears. Scientia Horticulturae. 134:53-59.
Baldwin, E.A., Bai, J. 2010. Physiology of fresh-cut fruits and vegetables. In: Martin-Belloso, O., Soliva-Fortuny, R., editors. Advances in Fresh-Cut Fruits and Vegetables Processing. Boca Raton, FL: CRC Press. p. 87-113.
Sitther, V., Harris, D.L., Dhekney, S., Bai, J., Baldwin, E.A., Yadav, A. 2011. Total phenol content of guava fruit and development of an in vitro regeneration protocol amenable to genetic improvement. International Journal Food Safety, Nutrition and Public Health. 4:225-236.
Chambers, A., Whitaker, V., Gibbs, B., Plotto, A., Folta, K. 2012. Detection of the linalool-producing NES1 variant across diverse strawberry (Fragaria spp.) accessions. Plant Breeding. 131(3):437-443.
Baldwin, E.A., Bai, J., Plotto, A., Cameron, R.G., Luzio, G.A., Narciso, J.A., Manthey, J.A., Widmer, W.W., Ford, B.L. 2012. Effect of extraction method on quality of orange juice: hand-squeezed, commercial-fresh squeezed and processed. Journal of the Science of Food and Agriculture. 92:2029-2042.
Narciso, J.A., Ference, C.M., Ritenour, M., Widmer, W.W. 2012. Effect of copper hydroxide sprays for citrus canker control on wild type Escherichia coli. Letters in Applied Microbiology. 54:108-111.
Baldwin, E.A., Hagenmaier, R.D., Bai, J. 2011. Introduction. In: Baldwin, E.A., Hagenmaier, R., Bai, J., editors. Edible Coatings and Films to Improve Food Quality. 2nd edition. Boca Raton, FL: CRC Press. p.1-12.
Cheng, G., Baldwin, E.A. 2012. Regulatory Aspects of Coatings. In: Baldwin, E.A., Hagenmaier, R., Bai, J., editors. Edible Coatings and Films to Improve Food Quality. 2nd edition. Boca Raton, FL: CRC Press. p.383-415.
Dea,S.,Ghidelli,C.,Perez-Gago,M.,Plotto,A.2012. Coatings for minimally processed fruits and vegetables. In: Baldwin,E.A., Hagenmaier,R., Bai,J., editors. Edible Coatings and Films to Improve Food Quality. 2nd edition. Boca Raton,FL: CRC Press. p.243-289.
Bai,J., Plotto,A. 2012. Coatings for fresh fruits and vegetables. In: Baldwin, E.A.,Hagenmaier, R.,Bai, J.,editors. Edible Coatings and Films to Improve Food Quality. 2nd edition. Boca Raton,FL:CRC Press. p.185-242.