Project Number: 1245-43440-004-00
Project Type: Appropriated

Start Date: Jun 02, 2010
End Date: Jun 01, 2015

Objective:
1. Evaluate the effects of pre-harvest production and post-harvest processing and storage treatments on fruit flavor, maintenance and/or enhancement in diverse accessions and breeding lines of Capsicum pepper, Malus serversii apple and blueberries; determine underlying molecular mechanisms controlling flavor quality. 2. Evaluate technologies to maintain the quality and marketability of fresh and fresh-cut produce through integrated microbiological and physiological approaches and innovations in post harvest handling, sanitation, and modified atmosphere packaging technology.

Approach:
Mature produce from 30 to 240 accessions of non-cultivated and/or cultivated accessions of Capsicum peppers, Malus sieversii apple, lettuce and assorted microgreens, rabbiteye blueberry, raspberry, strawberry and tomato will be evaluated for flavor and nutritional quality-related substances using established gas chromatography, liquid chromatography and sensory methods and for shelf stability and overall marketability. Substances evaluated analytically will include aromatic volatiles, free sugars, organic acids, capsaicinoids and their analogs (pepper only), antioxidants (e.g., anthocyanidins, carotenoids, phenolic acids), vitamins (provitamin A, B9, C, E, K1) and radical scavenging/antioxidant enzymatic activities. Fresh and fresh-cut produce from accessions identified as having high flavor and/or associated nutritional quality attributes will be further evaluated for sensory quality using consumer (untrained) and trained panelists and for efficacy of pre- and post-harvest processing treatments to further enhance their quality. Pre-harvest treatments will primarily focus on emerging foliar potassium fertilization protocols that enhance nutritional quality and post-harvest treatments will emphasize modified atmosphere and light storage treatments (microgreens only), novel fresh-cut wash operations (primarily fresh-cut lettuce) and new technologies for improved cold chain integrity. Since these pre- and post-harvest treatments can affect overall quality, quality attributes of color, texture, visual appearance, electrolyte leakage, decay and microbial (aerobic, psychotropic, lactic acid bacteria, yeast and molds) growth will be determined as appropriate. If laboratory studies indicate that an intermediate rinse step between cutting and washing lettuce reduces accumulation or organic matter in the rinse water and improves sanitation, pilot plant evaluations will be conducted using specially designed processing equipment supplied by industry partners. In addition, intraspecific crosses will be made between peppers with high flavor/nutritional quality and commercial bell pepper breeding lines. Resulting F1 families will be selfed to create F2 mapping populations and segregating F2 populations will be selfed to create F3 populations. Fruit from F3 plants and parental lines will be phenotyped for flavor/nutritional quality and segregating F2 populations will be genotyped using SNP marker technology: quantitative trait loci (QTL) for flavor/nutritional quality attributes will be identified. In cooperation with collaborators, these QTLs will be introgressed into elite bell pepper breeding lines.