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ARS Home » Southeast Area » Fort Pierce, Florida » U.S. Horticultural Research Laboratory » Citrus and Other Subtropical Products Research » Research » Research Project #438353

Research Project: Determination of Flavor and Healthful Benefits of Florida-Grown Fruits and Vegetables and Development of Postharvest Treatments to Optimize Shelf Life an Quality for Their Fresh and Processed Products

Location: Citrus and Other Subtropical Products Research

Project Number: 6034-41430-007-00-D
Project Type: In-House Appropriated

Start Date: Jun 5, 2020
End Date: Jun 4, 2025

Objective:
Objective 1: Establish commercially usable chemical and sensory characteristics of new citrus, strawberry, and avocado genotypes and new crops (microgreens) from subtropical and tropical climates. Sub-Objective 1a: Develop chemical and sensory profiles of Citrus hybrids tolerant to citrus greening disease or Huanglongbing (HLB). Sub-Objective 1b: Identify chemical and sensory characteristics for Florida-grown (avocado, strawberry, peach) and new crops (microgreens, tropical fruit) adapted to tropical/subtropical regions. Objective 2: Enable real-time, commercial pre- and postharvest treatments to optimize shelf life of new genotypes and new crops using packaging, coatings, aqueous treatments, sanitizers, maturity markers and/or addition of flavor modulators. Sub-Objective 2a: Develop methods to mask undesirable bitterness in orange and other citrus juice using flavor modulators. Sub-Objective 2b: Develop novel deliveries of antimicrobial volatiles and/or plant essential oils using microencapsulated beads and/or coating technology, combined or not with modified atmosphere packaging to prevent decay in packaged fruit. Objective 3: Isolate and test biomarkers in fruits (citrus, small fruit) with unique taste, flavor and healthful qualities for better commercial management strategies. Sub-Objective 3a: Identify the best flavor combinations for an ideal orange or citrus juice. Sub-Objective 3b: Identify the best flavor combinations for an ideal fresh strawberry. Sub-Objective 3c: Identify biomarkers in citrus with unique taste, flavor and healthful qualities.

Approach:
Fruits from breeding programs will be evaluated for eating quality and storability using sensory evaluations, chemical and texture analyses. For citrus, hybrids tolerant to HLB will be considered for juice quality and blending, in addition to eating quality as fresh fruit. Other fruit will include strawberries, peaches, avocadoes, tropical fruit (papaya, vanilla). A new crop, microgreens, will be included in the evaluations. For citrus and strawberries, sensory and flavor data will be statistically modelled in order to establish either ideal fruit quality markers, or criteria for non-acceptability, that can be used by breeders during the selection process. Furthermore, for citrus, identification of chemical off-flavor/off-taste targets will serve as a basis to test various flavor modulators that could mask undesirable flavors in orange juice. Potential flavor modulators include modified proteins, peptides, or amino acid, and other chemical family molecules will be tested when available. For strawberries, models will be validated by reconstitution experiments. For peaches, samples will consist of a diversity of new and old cultivars, some obsolete while others having withstood a long commercial life. The chemical fingerprint will help breeders understand the differences among genotypes for continuous effort in breeding and selection of new cultivars. For tropical fruit and microgreens, all being new crops, data will be more exploratory and descriptive than hypothesis-driven. Postharvest evaluations will be performed to test new methods of delivery of volatile antimicrobials in the form of spray-dried slow release powder placed in small fruit (strawberries, blueberries) clamshells. Control of postharvest decay as well as residual taste of volatiles will be evaluated. In citrus, Diplodia stem-end rot, due to Lasiodiplodia theobromae, has become more prevalent in citrus infected by HLB. This project will evaluate pre- and post-harvest fungicide treatments to control Diplodia stem-end rot. Finally, this project will evaluate phytochemical biomarkers in orange juice that have biological activity in mammals. Many flavonoids in citrus have been shown to have beneficial effects in human chronic diseases. Metabolites of flavonoids fed to experimental animals were previously extracted and isolated from various organs (liver, kidneys); they remain to be identified and quantified. Furthermore, their bioactivity will be evaluated in in vitro tests with emphasis on inflammation.