Performing Department
(N/A)
Non Technical Summary
The goal of this project is to advance the safe adoption of dynamic controlled atmosphere (DCA) storage, a recent advance in CA technology that is based on the principle of lowering O2 concentrations to the lowest tolerated by the fruit without causing injury, thereby reducing or eliminating quality loss associated with ripening storage by the US apple industry. A team of researchers with backgrounds in horticultural, sensory, economics, and omic sciences will address factors identified by the industry advisory committee with 5 objectives: 1) To develop best management practices for handling DCA stored apple fruit, especially premium and emerging cultivars, to reduce chemical inputs, maximize quality, and minimize the risk of storage-related disorders; 2. Understand how the extreme modification of oxygen by DCA affects respiratory metabolism, ripening biology, and disorder development of stored apple fruit; 3. Understand how modifications in ripening biology resulting from DCA storage are perceived and valued in consumer sensory testing and by storage practitioners; 4. Create a decision support tool, based on analyses of economic and sociological factors, to inform investment in DCA technology; and 5. Translate research findings into communication outputs for postharvest and horticultural scientific, educational, and practitioner communities.
Animal Health Component
70%
Research Effort Categories
Basic
20%
Applied
70%
Developmental
10%
Goals / Objectives
The goal of this project is to provide the knowledge that will allow the safe adoption of dynamic controlled atmosphere (DCA) storage technology where it is most useful in United States (US) apple industry. The goal will be met by work in five objectives.Objective 1: The development of best management practices for handling DCA treated fruit will integrate information generated from biological, sensory, and economic data from research objectives 2, 3, and 4, respectively. We will evaluate options for atmosphere establishment, temperature control and plant growth regulator interactions in apple storage management as they relate to successful DCA implementation. Additional data collected from research in objectives 2-4 will then be used to flesh out management practices for apple storage under DCA, adding new insights and recommendations to optimize fruit quality and production efficiency.Objective 2: Fruit metabolic responses to low O2, elevated CO2, and ethylene action will be investigated using state-of-the-art analyses. The determination of the lower O2 limit (LOL) or anaerobic compensation point (ACP) and its year-to-year and regional variability will be measured for both traditional and premium cultivars. Low O2 levels will be applied in combination with a range in CO2 concentrations to understand the interplay between these two gases. Volatile (aroma-related) and non-volatile metabolite analyses will link to sensory analyses of Obj. 3.Objective 3: The degree to which stressful atmospheres impact the perception of visual, olfactory, taste, and textural quality attributes will be determined and described both quantitatively and qualitatively for fruit given storage treatments as outlined in Obj. 1. Consumer panel evaluations will be interwoven with metabolite (Obj. 2) and fruit quality (Obj. 1) analyses to permit us to define the advantages and limitations of this new technology.Objective 4: The primary economic objective is to evaluate the costs and benefits associated with the adoption of the DCA storage technology for the U.S. apple industry. We will use information from best management practices for DCA stored apple (Obj. 1), DCA effects on metabolites related to apple quality in storage (Obj. 2) and consumer sensory perceptions (Obj. 3) to assess benefits. We will use a dynamic cost-benefit analysis to evaluate the economic implications of adoption eastern and western US storage operators. In addition, we will conduct a series of market simulations using an equilibrium displacement model to assess the potential market effects throughout the supply chain.Objective 5: The translation of information generated by this project to industry stakeholders and scientific peers will employ print and web-based platforms to disseminate educational bulletins and other outreach products. Important among the outputs is a decision support tool that will assist storage entities in decisions related to technology uptake. We will conduct both general and targeted online and in-person formal extension programs, including industry stakeholder discussions, in association with each cooperator institution. We will direct newsworthy outcomes to regional and national fruit industry-oriented print and online media.
Project Methods
Objective 1Fruit maturity: Ten fruit per replicate in each experiment will be used for measurement of harvest indices - internal ethylene concentration, firmness, titratable acidity, soluble solids content, delta absorbance, and starch pattern index using standard laboratory procedures.Fruit quality: External and internal defects and physiological disorders will be assessed visually, counting the number of fruit affected and severity in some cases. Internal defects will be recorded after cutting the fruit transversely at the equator. Aroma headspace volatiles for whole fruit will be quantified using analysis by GC/MS. For a given treatment combination, 5 individual fruits will be selected, placed singly into inert, sealed chambers and the headspace sampled by solid phase microextraction after a 20-min incubation period at 20 °C. For aroma recovery analysis, fruit will be analyzed weekly until aroma production maximizes. We will predict the impact of aroma on sensory perception using descriptors, known odor impact thresholds and ester abundance and correlate with off-aroma reports from sensory analysis.1-MCP treatment: Fruit will be cooled to a target temperature appropriate for each cultivar/subobjective, and treated with 1-MCP [1 µL L-11-MCP (SmartFresh tablets, 3.8% a.i., AgroFresh Co., Spring House, PA or EasyfreshTM, 3.3% a.i., Fine Americas, Walnut Creek, CA) for 24 h in a 4000-L plastic tent using a release and fan system].Mineral Analysis: A composite sample of 5-7 fruit per replicate (taken at harvest) for each growing environment will be used for this analysis. Fruit peel will be removed from the equator and oven-dried at 60°C for 3 days. After that time, tissue will be pulverized and homogenized, and 200 mg per sample used for digestion in HNO3. Minerals will be determined by microwave-induced plasma atomic emission spectrometry (MP-AES).Lab Pod RQ: Lab Pods will be run using SCS 6000 integrated hardware and software. Atmosphere establishment will be programmed to generate desired oxygen and CO2levels. Respiration and RQ measurements followed by pO2and pCO2adjustment will take place daily. Data will be stored locally and in the cloud on the SCS 6000 and SCS secure servers, respectively.HarvestWatchTM: HarvestWatch FIRM sensors will be placed in CA chambers. O2levels will in the chambers be manipulated and the Favalues tracked to determine the LOL/ACP and the desired O2setpoint.Objective 2Profiling metabolism during O2adjustment for ACP determination. Profiling experiments will track differences in metabolite profiles at 5 selected timepoints during the O2pull-down period for determination of the ACP. All timepoint/treatment combinations will be represented by 5 or more biological replications. Most samples will be sourced from DCA storage at WA, MI, and NY laboratories. Tissue sampling has to occur without disrupting the pO2determination. Consequently, multiple chambers, using any one DCA monitoring technology, will be used for imposing the treatment condition, with different chambers being accessed on each of the 5 timepoints during and after DCA target pO2establishment. For each timepoint, fruit from 1 chamber will be removed, sampled, and stabilized/frozen within 10 minutes of removal. Subsequent chambers will be sampled for additional timepoints. Five biological replications will be sampled from 18-20 fruit (composite samples of 3-4 fruit). Cortex tissue will be sampled by flash freezing in LN2, shipped to WA on dry ice, and stored at -80 °C until metabolic profile analysis (Leisso et al., 2015). This tissue will be for used for metabolite profiling (see below).Elevated pCO2: Focused pCO2/pO2combination experiments will be performed at the WA and MI locations. Cortex tissue will be sampled by flash freezing in LN2, shipped to WA on dry ice, and stored at -80 °C until metabolic profiling.Metabolic (including volatile) profiling: Metabolic profile of apple tissue will be analyzed using 3 different extractions and combinations of GC-MS and LC-MS to provide a less biased analysis of over 800 metabolites in the pome fruit metabolome. Metabolite information will be extracted from mass spectral chromatograms using deconvolution and identification protocols. Methods for unbiased profiling are based on methods used in the USDA laboratory.Global data analysis: To model metabolomic impacts, analysis of metabolite data will employ a variety of techniques with the general goal of associating metabolic events with experimental inputs over time course studies. Metabolic profiles can be analyzed alone or together using appropriate univariate and multivariate analyses as well as network modeling as required by dimensionality.Objective 3Eight sensory tests per year will assay fruit from experiments outlined in Objective 2 to test consumer response to appearance, texture, flavor, aftertaste/residual, purchase intent, and the respondents' overall liking of the samples. Fruit will be tested on 2 separate removal dates, to investigate medium and long-term storage regimes. A total of 140 panelists will be recruited, to account for up to N = 20 panelist attrition over the course of the study. Samples will be assessed using the Quartermaster corps. 9-point hedonic scale for overall and individual attribute liking, as well as perceived importance of chemical-free labeling, all of which can be vital in determining purchase intent. After liking questions, JAR scaling of flavor and texture attributes will be combined with overall liking of the samples to generate penalty analysis graphs for all treatments, thus determining the impact of any off-flavors or textural deficits on consumers' purchase intent.Objective 4"In what ways and to what extent does DCA improve the economic standing of those who implement this technology?" will be addressed. We will develop a framework to characterize the changes in costs and benefits from using DCA relative to other systems of storage. We will conduct the analysis for multiple scenarios that include specific cultivars (e.g., 'Gala', 'Honeycrisp', and 'Cosmic Crisp'), different sized storage operations, and for storage operations located in different regions. We will draw on information to describe the changes in annual costs associated with DCA use, changes in fruit quality and fruit loss in storage, and details about consumer preferences for fruit stored in DCA.Objective 5Survey development and implementation. Prior to the initiation of storage work, surveys will be developed to answer the question: "How does the level of familiarity of storage operators with DCA in each region change following implementation of this project?" We will document the expectation of storage operators regarding responses of fruit to the treatments that will be applied throughout the course of these studies We will engage with current DCA practitioners and non-practitioners to document their current understanding of what might constitute best management practices for DCA. At the conclusion of the project, a similar survey instrument will be used to determine shifts in clientele awareness and knowledge regarding DCA.DCA Best Management Guide development.The development of best management practices for integration of DCA technology will integrate information generated from biological, sensory, and economic data collected throughout the project. The data collected from research on objectives 1 to 4 will then be used to flesh out any management practices currently in place, adding new insights and recommendations for practices to optimize fruit quality and production efficiency.