Location: Food Quality Laboratory
2016 Annual Report
Objectives
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 sieversii 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, and rabbiteye blueberry 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. Additional species to be studied include lettuce, tomatoes, strawberries, raspberries, and assorted microgreen.
Progress Report
Performed extensive sensory and instrumental analyses of product quality, supporting the success of USDA-ARS research projects and collaborators at University of Maryland and our industry stakeholder. Utilizing the unique sensory and instrumental analysis resources, USDA-ARS scientists at Beltsville, Maryland, conducted extensive quality evaluation of fresh produce, including more than 110 sensory panels for a variety of fruits and vegetables such as lettuce, melons, cabbages, and strawberries. These activities contributed significantly to the accomplishments of two USDA ARS research projects, and two additional collaborative research projects with University of Maryland and a fresh-cut processor. Findings provide critical information for the selection of a lettuce variety that is suitable for east-coast growing conditions, on quality of melons grown conventionally and organically, strawberries that received UV treatment at different maturity levels, and the commercialization and validation of a novel and transformative new fresh-cut processing technology taken on by our industry stakeholder.
Developed a novel wash system (patent-pending) that enables early removal of organic materials while conserving water usages during fresh-cut produce processing. In current commercial production facilities, organic exudate released from cut tissues reacts immediately and continuously with chlorine and other sanitizers, and consequently reduces the efficacy of these sanitizers on bacteria inactivation. The accumulation of organic materials in the wash system requires addition of both fresh water to dilute the organic materials concentration and ever-larger amounts of sanitizer chemicals in order to maintain an adequate concentration of active sanitizer. Thus, a new approach was developed to remove organic materials early in the process without damaging plant tissues. This technology is expected to generate a number of benefits over the current state-of-art: first, by removing significant exudate very early in the process, subsequent sanitizing steps are not faced with high, chlorine-depleting organic load; second, because the produce is suspended in air, rather than in contact with a belt, the risk of "bruising" or other tissue damage due to water impact (especially for delicate produce) is greatly reduced; third, this approach allows one to separately collect (and treat) spent process water with high organic load, without mixing it with water collected from subsequent washing stages having lower organic load. This has the potential to significantly reduce the cost of water treatment (for either reuse or discharge), and to increase the fraction of the water that can be economically reused. The idea has been concepturized; device designed and fabricated. Results from first generation prototype is very encouraging.
Accomplishments
1. Groundbreaking research on microgreens promoted new healthy food trends. Microgreens are young seedlings of edible plants used to embellish cuisine. ARS pioneering research revealed higher levels of phytonutrients and bioactive compounds in microgreens than in their mature counterparts. Follow up studies further documented their nutritional mineral profiles, sensory attributes, consumer preferences of microgreen varieties, and optimum growing, harvesting, and storage conditions. Our studies and communications with stakeholder also attracted strong media attention. Collectively, microgreens have recently been called the best low-budget “startup” for new urban farmers, the “micro greening of America”, the new “culinary buzzwords”, and one of the top five food trends. This research and outreach has stimulated the burgeoning of the microgreen industry, and greater availability of nutritious fresh foods.
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Review Publications
Kou, L., Yang, T., Luo, Y. 2015. Effects of pre- and postharvest calcium treatments on shelf life and postharvest quality of broccoli microgreens. HortScience. 50(12):1801–1808.
Wang, S., Luo, Y., Li, J., Zhou, B., Jacangelo, J., Schwab, K.J. 2015. Assessment and speciation of chlorine demand in fresh-cut produce wash water. Food Control. 60:543-551.
Xiao, Z., Codling, E.E., Luo, Y., Nou, X., Lester, G.E., Wang, Q. 2016. Microgreens of brassicaceae: mineral composition and content of 30 varieties. Journal of Food Composition and Analysis. 49:87-93.
Xio, Z., Lester, G.E., Park, E., Saftner, R.A., Luo, Y., Wang, Q. 2015. Evaluation and correlation of sensory attributes and chemical compositions of emerging fresh produce: Microgreens. Journal of Agricultural and Food Chemistry. 110:140-148.
De Frias, J.A., Luo, Y., Kou, L., Zhou, B., Wang, Q. 2015. Improving spinach quality and reducing energy costs by retrofitting retail open refrigerated cases with doors. Postharvest Biology and Technology. 31(8):114-120.
