Source: UNIVERSITY OF GEORGIA submitted to
ADVANCING ONION POSTHARVEST HANDLING EFFICIENCY & SUSTAINABILITY BY MULTIMODAL QUALITY SENSING, DISEASE CONTROL, AND WASTE STREAM MANAGEMENT
Sponsoring Institution
National Institute of Food and Agriculture
Project Status
COMPLETE
Funding Source
OTHER GRANTS
Reporting Frequency
Annual
Accession No.
0220061
Grant No.
2009-51181-06010
Cumulative Award Amt.
(N/A)
Proposal No.
2009-02520
Multistate No.
(N/A)
Project Start Date
Sep 1, 2009
Project End Date
Aug 31, 2013
Grant Year
2009
Program Code
[SCRI]- Specialty Crop Research Initiative
Project Director
Li, C.
Recipient Organization
UNIVERSITY OF GEORGIA
200 D.W. BROOKS DR
ATHENS,GA 30602-5016
Performing Department
Biological & Agr Engineering
Non Technical Summary
Onion is the third-largest fresh vegetable crop in the U.S. As a critical link between the farm and the consumer, postharvest handling plays a vital role in the onion industry. The current sorting and storage system is largely based on human inspection and unable to confront challenges like the growing demand for high-quality products from consumers and looming shortages in labor. For example, postharvest diseases, identified by stakeholders as the most serious threat to onion profitability, often cause 50% storage losses due to lack of detection tools and management strategies. As a result of diseases and disorders, discarded onions from the packinghouse or storage can lead to environmental pollution as well as increased disease pressure in the field. This Standard Research and Extension Project will enable an unprecedented leap in postharvest handling efficiency and sustainability through a systems approach and trans-disciplinary research and extension effort integrating three major themes: (i) improve the efficiency of online sorting by integrating X-ray and hyperspectral imaging technologies through a sensor fusion approach; (ii) reduce storage losses by developing gas sensing and tracing technologies, as well as evaluating the efficacy of cultural and chemical postharvest disease controls; and iii) manage the onion waste stream by developing a high-rate anaerobic digestion system to convert discarded onions into energy. A socioeconomic analysis to assess the potential for technology adoption along with comprehensive outreach efforts ensures that new technologies will truly benefit stakeholders.
Animal Health Component
70%
Research Effort Categories
Basic
10%
Applied
70%
Developmental
20%
Classification

Knowledge Area (KA)Subject of Investigation (SOI)Field of Science (FOS)Percent
2121451116020%
4031451202020%
4031451301010%
5031451116010%
5031451202030%
5031451301010%
Knowledge Area
212 - Pathogens and Nematodes Affecting Plants; 403 - Waste Disposal, Recycling, and Reuse; 503 - Quality Maintenance in Storing and Marketing Food Products;

Subject Of Investigation
1451 - Onion, garlic, leek, shallot;

Field Of Science
2020 - Engineering; 1160 - Pathology; 3010 - Economics;
Goals / Objectives
Onion is the third-largest fresh vegetable crop in the U.S. and the second most valuable vegetable in the world. As a critical link between the farm and consumers, postharvest handling is vital for the profitability and sustainability of the onion industry. However, onion postharvest handling at both fresh-market and storage levels faces enormous challenges such as looming labor shortages, significant storage losses, and enormous quantities of cull onions that need to be disposed of. In most packinghouses in the nation, onions are visually inspected by human workers, which not only requires large amount of workers, but fails to detect internal defects and latent diseases. These onions with both external and internal defects have a direct adverse effect on market value, consumer satisfaction, and the profit for onion growers and shippers. At the storage room, due to lack of effective detection methods, growers cannot take measures until the onions exhibit visual symptoms that make them unsalable. This storage loss caused by Botrytis neck rot could reach as high as 50 to 70% in some years. At both the packinghouse and in storage, large portions of onions are discarded due to physical defects or pathogen infection. These cull onions are usually disposed of in the field, which potentially pollutes water bodies and introduces pathogens into the soil, creating a vicious cycle in onion production. In addressing these challenges, the long-term goal of this project is to enhance onion postharvest handling efficiency and sustainability via a systems approach and trans-disciplinary research and extension effort integrating three major themes: (i) improve the efficiency of online sorting by integrating X-ray and hyperspectral imaging technologies through a sensor fusion approach; (ii) reduce storage losses by developing gas sensing and tracing technologies, as well as evaluating the efficacy of cultural and chemical post-harvest disease controls; and iii) manage the onion waste stream by developing a high-rate anaerobic digestion system to convert discarded onions into energy. Specific objectives are to: 1). Enhance the efficiency of onion quality sorting by a multimodal sensing platform using X-ray and hyperspectral imaging technologies and determine the effect of nondestructive inspection on onion quality as evaluated by a sensory panel; 2). Develop a gas sensing and tracing method for disease detection in storage and evaluate onion postharvest disease management practices; 3). Manage the onion waste stream and mitigate environmental pollution using an anaerobic digestion system; 4). Evaluate social implications and economic impacts of these technologies; and 5). Engage in outreach and technology transfer with stakeholders. This project addresses three focus areas of the SCRI and priorities established in stakeholder surveys.
Project Methods
Objective 1: A multimodal sensing platform using X-ray and hyperspectral imaging technologies will be developed to evaluate onion quality. A multitemporal and multimodal image registration algorithm will be investigated at the pixel level data fusion. Features extracted from X-ray and hyperspectral images will be concatenated into a single feature vector and fed into an artificial neural network for pattern classification. The evolutionary strategy will be used as a heuristic optimization algorithm to select the most relevant features from two sensing sources. Onion samples will be evaluated by consumers and an experienced panel to assess the effect of X-ray and spectral imaging on consumer perception. Objective 2: Volatile compounds emitted by two postharvest diseases of onions, Botrytis neck rot and sour skin, will be characterized by the gas chromatograph and mass spectrometry. Customized gas sensors will be deployed and tracing algorithms will be developed to detect and pinpoint disease locations in onion storage room. Four onion disease management practices will be evaluated for their efficacy and efficiency to reduce Botrytis and bacterial diseases in postharvest. Objective 3: The physical and chemical characteristics of the onions (total solids, volatile solids, pH, Brix and chemical oxygen demand) will be measured in the beginning of this project. A laboratory-scale anaerobic digester will be designed in the first year to decompose discarded onions in a vessel where oxygen is absent. In the year 3, a pilot-scale anaerobic digestion system will be developed on UGA campus and tested at a local packing shed. Feedstock that can be used for anaerobic digestion and composting processes will be reviewed and defined to better promote community development in rural area. Objective 4: These developed technologies will have potentially a profound social and economic impact. Social analysis will be conducted through focused group interviews and online surveys to evaluate social, environmental, and technological concerns. Economic analyses will be conducted to determine production risk minimization levels by delineating breakeven probabilities and construction of a decision tree matrix. Objective 5: Three technologies developed from Objectives 1-3 will be demonstrated in commercial onion packing sheds and storage facilities. Detailed feedback will be gathered and shared among investigators and manufacturers. The team will engage in onion community by effective and trusted Cooperative Extension paths of technology transfer and implementation. Two workshops will be held in conjunction with National Onion Association meeting and National Allium Research Conference. Results and derived recommendations for innovative technologies developed in this project will be presented in national conferences and regional meetings. A Wiki-based website will be developed as an effective information delivering vehicle for onion postharvest handling, storage, processing, and marketing information, and in particular the outcomes of this project.

Progress 09/01/09 to 08/31/13

Outputs
Target Audience: The primary target audience for this project consists of commercial onion growers, processors in the southeast, northwest, southwest, and northeast regions of the United States. Knowledge transfer has occurred in educational sessions at the National Allium Research Conference, National Onion Association Meetings, the Southeast Fruit and Vegetable Conference, County agent trainings and production meetings. The project website has been visited regularly by stakeholders with more than 2000 hits per month. Changes/Problems: Nothing Reported What opportunities for training and professional development has the project provided? The project has trained the next generation of scientists and engineers to work on onions. It has brought 21 graduate students onboard to provide them with educational and training opportunities. Non-destructive sensing systems and proprietary software were developed for onion postharvest disease detection. A total of 58 publications were generated by the team. Onion industry surveys were completed for Colorado, Idaho, New York, and Arizona in 2010. Anaerobic filters and anaerobic sequencing batch reactors were set up to convert the onion waste into biogas. The presentations and visits to farmers and processors have helped engage stakeholders. A project website was established to disseminate the knowledge developed from this project to stakeholders. Regular visits to this website exceeded 2000 per month. The project has provided training/professional development opportunities for the following students: Weilin Wang (MS/Ph.D. student, UGA), Tharun Konduru (MS student, UGA), Haihua Wang (visiting Ph.D. student, UGA), Anna Watson (MS/Ph.D. student, UGA), Antoinette Menuel (MS student, UGA), Sean McKeown (MS student, UGA), Xiaoliang Shao (PhD student, Tsinghua), Manish Bansal (MS student, UGA), Jolene Glenn (MS student, Auburn), Stephanie Szostek (MS student, Colorado State), Anne Morrison (technician, UGA), Katherine Robbins (graduate assistant, UGA), Anthony Bateman (Research Professional, UGA), Hunt Sanders (Pathology, UGA), Rajagopalbabu Srinivasan (Entomology, UGA), David Riley (Entomology, UGA), Randy Hill (VOVRC Superintendent, UGA), Denny Thigpen (Research Technician, UGA), Reid Torrance (UGA Area Onion Agent), Kris Otto and Mark McMillan (Research Technicians, Colorado State). How have the results been disseminated to communities of interest? Presentations have been made in various venues such as the National Allium Research Conference, the American Society of Biological and Agricultural Engineers (ASABE), the National Onion Association Conference, Southeastern Region Fruit and Vegetable Conference, Extension trainings, and production meetings. A website of this project (alliumnet.com/PostHarvestHandling.html) was regularly visited by our stakeholders. What do you plan to do during the next reporting period to accomplish the goals? Nothing Reported

Impacts
What was accomplished under these goals? Objective 1: 1) A liquid crystal tunable filter based near infrared (NIR) hyperspectral imaging system was developed to detect sour skin disease in onions. 2) A line scan hyperspectral imaging system (visible to near infrared spectra) was developed to predict onion internal quality attributes such as dry matter content, soluble solid content, and firmness. 3). The optical properties of onion tissues were investigated in both a single wavelength (633 nm) and across a broad spectrum (500-1700 nm). Monte Carlo simulation was conducted to model the light propagation in multi-layer onion tissues in healthy, Botrytis neck rot and sour skin infected onions. 4) X-ray images (computed tomography, or CT) were studied to detect onion internal diseases. 5) The NIR spectrometry data were correlated with the chemical analysis data (Brix, Pungency, LF/IS) and the intensity of pungency and sweetness scored by a panel of experienced judges. 6) Microwave technology was investigated to detect the moisture content (between 6% and 92%) of onions at 13.36 GHz using an open-ended coaxial-line probe connected to a network analyzer. Objective 2: 1) A customized SmartNose system was developed to detect rot of onions in storage. Detection of onions infected by sour skin in storage using a commercial sensor (zNoseTM) was also investigated. 2) Several onion disease management strategies were evaluated, including postharvest chemical drenching, sulfur dioxide and ozone treatments in storage. Field studies were conducted to study the effect of the double-cropping system. 3) Onions with control and IPM treatments were harvested and evaluated regarding the incidence of Botrytis neck rot and bacterial soft rot in Colorado and Idaho. Objective 3: 1) Onions from Georgia, New York and Colorado were tested for pH, COD, alkalinity, brix, moisture content and ash content. 2) A laboratory-scale anaerobic digester (V=90 L) was designed, operated and optimized in terms of feed rate, and retention time. Yield of methane and treatment efficiency was monitored as a function of optimization. 3) A pilot-scale AD system (V=3000 L) was developed on UGA Tifton campus and tested with onions from a local packing shed. Objective 4: 1) Extension research has been done about the onion industry which included onion production practices, onion growing area-specific budgets, historical input and market prices for each project state, review of Federal Marketing Order programs, and onion industry websites and university extension and research publications. 2) Focused group interviews were conducted for onion producers. 3) Numerous graduate students were trained during the project implementation. 4) Presentations have been made in various venues such as the National Allium Research Conference, the American Society of Biological and Agricultural Engineers (ASABE), the National Onion Association Conference, Southeastern Region Fruit and Vegetable Conference, Extension trainings, and production meetings. 5) A website of this project (alliumnet.com/PostHarvestHandling.html) was regularly visited by our stakeholders. Outcomes/Impact The technologies developed from this project could have significant impact on and greatly benefit the postharvest handling sector of the onion industry. Rapid, nondestructive, and automated sorting technologies will greatly enhance onion handling efficiency, reduce labor and management related costs (account for 50% of the operation costs in a typical packing house), and improve onion product quality on the shelf and consumers satisfaction, therefore creating both economic and social benefits to onion growers, packers, and consumers. The fundamental understanding of the onion optical properties can be used to develop appropriate optical techniques to improve quality control of onions. Our research demonstrated for the first time that the interactance mode of the hyperspectral imaging technique can be used to quantitatively predict the internal quality properties of an onion. The technology can be used to screen onions with high dry matter content, which has the practical value to the onion breeding industry (more than $100 million in revenue). Our investigation also provides convincing evidence that near infrared reflectance and chemical analysis of pungency compounds are reliable instrumental measures of sensory sweetness and sensory pungency, respectively. Microwave sensing offers an opportunity to determine nondestructively the amount of moisture in the onion by sensing its dielectric properties. The measurements and models completed constitute the foundation for the development of a sensor for determining the degree of curing an onion has undergone. The effective sensing technology (SmartNose) for disease detection in storage and practices for disease management will reduce the massive storage losses (50% in some years) and bring economic benefits to onion producers and handlers. Our study found that mixing the onion waste with dairy waste at a 50/50 mixture provided a good feedstock for fixed film digesters. The anaerobic fixed film systems will turn onion waste (>10% of harvested onions; 68 million lbs in Georgia alone) into energy, which will not only mitigate or eliminate environmental pollution and disease propagation in onion fields, but also generate biogas which can be used to power the onion postharvest handling facility, making onion postharvest handling both environmentally and economically sustainable.

Publications

  • Type: Journal Articles Status: Published Year Published: 2013 Citation: Wang, W. and C. Li. 2013. Measurement of the light absorption and scattering properties of onion skin and flesh at 633 nm. Postharvest Biology and Technology. 86: 494501. McKeown, Murat Sean, et al. 2012 Dielectric spectroscopy measurements for moisture prediction in Vidalia onions. Journal of Food Engineering 111(3): 505-510. Wang, H., C. Li, and M. Wang. 2013. Quantitative determination of onion internal quality using hyperspectral imaging with reflectance, interactance, and transmittance modes. Transactions of ASABE. 56(4): 1-14. Wang, W., C. Li, W. Tollner and G. Rains. 2012. Development of software for spectral imaging data acquisition using LabVIEW. Computers and Electronics in Agriculture. 84: 68-75. Wang, W., C. Li, W. Tollner, G. Rains and R. Gitaitis. 2012. Shortwave Infrared Hyperspectral Imaging for Detecting Sour Skin (Burkholderia Cepacia)-Infected Onions. Journal of Food Engineering. 109(1): 38-48. Wang, W., C. Li, W. Tollner, G. Rains, R. Gitaitis. A liquid crystal tunable filter based shortwave infrared spectral imaging system for food quality and safety inspection: design and integration. Computers and Electronics in Agriculture. 80: 126-134. Wang, W., C. Li, W. Tollner, G. Rains and R. Gitaitis. 2011. Development of an LCTF-based shortwave infrared spectral imaging system for food quality and safety inspection: calibration and characterization. Computers and Electronics in Agriculture. 80: 135-144. Li, C., R. Gitaitis, E.W. Tollner, P. Sumner, and D. MacLean. 2009. Onion Sour Skin Detection Using a Gas Sensor Array and Support Vector Machine. Sensing and Instrumentation for Food Quality and Safety 3(4): 193-202.
  • Type: Journal Articles Status: Published Year Published: 2013 Citation: Wang, H., C. Li, and M. Wang. 2013. Quantitative determination of onion internal quality using hyperspectral imaging with reflectance, interactance, and transmittance modes. Transactions of ASABE. 56(4): 1-14.
  • Type: Theses/Dissertations Status: Submitted Year Published: 2013 Citation: Tharun Konduru. 2013. Development of Automated MOS Based Gas Sensing Device for Sour Skin Disease Detection in Onions. MS Thesis, University of Georgia.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2013 Citation: Wang, Weilin; Li, Changying; Tollner, Ernest W., Haidekker, Mark A. Estimating the diameter and volume of Vidalia sweet onions using the consumer-grade RGB-depth camera. ASABE Paper No. 131593519. Kansas City, Georgia. July 2013.
  • Type: Websites Status: Published Year Published: 2012 Citation: An updated U.S. Onion Industry Analysis, March 2012, published on the AgMRC website: http://www.agmrc.org/commodities__products/vegetables/onion-profile/
  • Type: Theses/Dissertations Status: Submitted Year Published: 2011 Citation: McKeown, Murat Sean. 2011. Use of Microwave Dielectric Spectroscopy Measurements for Moisture Prediction in Vidalia Onions. Thesis. The University of Georgia.
  • Type: Journal Articles Status: Published Year Published: 2012 Citation: McKeown, Murat Sean, et al. 2012 Dielectric spectroscopy measurements for moisture prediction in Vidalia onions. Journal of Food Engineering 111(3): 505-510.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2012 Citation: McKeown, Murat Sean, Samir Trabelsi, and Ernest William Tollner. 2012. Dielectric Properties for Prediction of Moisture Content in Vidalia Onions. ASABE Paper No. 121337850. Dallas, Texas, July 29-August 1, 2012.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2013 Citation: McKeown, Murat Sean, Samir Trabelsi, and Ernest William Tollner. 2013 Microwave moisture sensing through use of a piecewise density-independent function. IEEE International Instrumentation and Measurement Technology Conference (I2MTC). Minneapolis, Minnesota, May 6-9, 2013.
  • Type: Theses/Dissertations Status: Submitted Year Published: 2011 Citation: Menuel, A. 2011. Palate Cleanser effectiveness in evaluating sweetness, bitterness, and pungency of sweet onions and sensory, chemical and instrumental techniques. MS Thesis, University of Georgia.
  • Type: Theses/Dissertations Status: Published Year Published: 2012 Citation: Manish Bansal. 2012. Onion postharvest treatment to inhibit diseases. MS Thesis, University of Georgia. Wang, Haihua. 2012. Developing hyperspectral imaging technologies for onion postharvest quality prediction. Doctoral Dissertation, China Agricultural University.
  • Type: Journal Articles Status: Published Year Published: 2012 Citation: Wang, W., C. Li, W. Tollner and G. Rains. 2012. Development of software for spectral imaging data acquisition using LabVIEW. Computers and Electronics in Agriculture. 84: 68-75.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2012 Citation: Wang, H., C. Li, M. Wang. 2012. Onion Internal Quality Prediction Using a Near Infrared Hyperspectral Imaging System. ASABE paper No. 121341135. Dallas, Texas, July 29-August 1, 2012. Wang, W. C. Li, R. Gitaitis, W. Tollner. 2012. Optical Properties of Healthy and Sour Skin-infected Onion Tissues in Vis-NIR Region. ASABE paper No. 121338380. Dallas, Texas, July 29-August 1, 2012. Wang, W., C. Li, W. Tollner, R. Gitaitis, G. Rains. 2012. Design and Calibration of Liquid Crystal Tunable Filter Based Spectral Imaging System. ASABE paper No. 1338382. Dallas, Texas, July 29-August 1, 2012. Konduru, T., C. Li, G. Rains. 2012. Development of A Customized Gas Sensor Array for Postharvest Disease Detection in Onions During Storage. ASABE paper No. 121337633. Dallas, Texas, July 29-August 1, 2012.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2011 Citation: Wang, W., C. Li, B. Tollner, R. Gitaitis, and G. Rains. 2011. Measuring Absorption and Scattering Properties of Onions at 632 nm using Inverse Adding Doubling Method. ASABE Paper No. 1110722. Louisville, Kentucky, August 8-10, 2011. Wang, H. C. Li, M. Wang. 2011. Onion Internal Quality Prediction using Line-scan Hyperspectral Imaging. ASABE Paper No. 1110708. Louisville, Kentucky, August 8-10, 2011.
  • Type: Websites Status: Published Year Published: 2011 Citation: Onion ipmPIPE Diagnostic Pocket Series, 2 page diagnostic cards, distributed nationally to more than 7500 stakeholders and posted online: http://www.alliumnet.com/IPMPipe.html
  • Type: Conference Papers and Presentations Status: Published Year Published: 2010 Citation: Hawkins, G.L. 2010. Innovative Tools and Best Practices for Regenerating Small Scale On Farm energy Projects. Presentation at 2010 Growing Powers National-International Urban and Small Farm conference. Milwaukee, WI. 10 September 2010.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2011 Citation: Morgan, K.L. (2011, October 19). Key Concepts Influencing Technology Adoption: Interviews with U.S. Specialty Crops Supply Chain Participants. Selected paper presented at 2011 Food Distribution Research Society Annual Conference, Portland, OR.
  • Type: Journal Articles Status: Published Year Published: 2012 Citation: Wang, W., C. Li, W. Tollner, G. Rains and R. Gitaitis. 2012. Shortwave Infrared Hyperspectral Imaging for Detecting Sour Skin (Burkholderia Cepacia)-Infected Onions. Journal of Food Engineering. 109(1): 38-48.
  • Type: Journal Articles Status: Published Year Published: 2011 Citation: Wang, W., C. Li, W. Tollner, G. Rains, R. Gitaitis. A liquid crystal tunable filter based shortwave infrared spectral imaging system for food quality and safety inspection: design and integration. Computers and Electronics in Agriculture. 80: 126-134. Wang, W., C. Li, W. Tollner, G. Rains and R. Gitaitis. 2011. Development of an LCTF-based shortwave infrared spectral imaging system for food quality and safety inspection: calibration and characterization. Computers and Electronics in Agriculture. 80: 135-144.
  • Type: Journal Articles Status: Published Year Published: 2012 Citation: Wang, W., C. Li, W. Tollner and G. Rains. 2012. Development of software for spectral imaging data acquisition using LabVIEW. Computers and Electronics in Agriculture. 84: 6875.
  • Type: Journal Articles Status: Published Year Published: 2010 Citation: Li, C., R. Gitaitis, and N. Schmidt. 2010. Detection of onion postharvest diseases by analyses of headspace volatiles using a gas sensor array and GC-MS. LWT - Food Science and Technology. 44: 1019-1025.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2010 Citation: Li, C., H. Schwartz, K. Mohan, J. Molnar, K. Morgan, R. Gitaitis, G. Hawkins, D. MacLean, R. Shewfelt, C. Thai, W. Tollner. 2010. Holistic approach to advance onion postharvest handling efficiency and sustainability. Invited poster presentation at ASHS annual meeting. Palm Desert, California, August 1-3, 2010.


Progress 09/01/11 to 08/31/12

Outputs
OUTPUTS: Objective 1: 1) The data from the line scan hyperspectral imaging system were further analyzed and a manuscript was written and submitted to a journal. 2) The optical properties of onion tissues were not only investigated at a single wavelength (632.8 nm), but examined across a broad spectra (500-1700 nm) using two spectrometers. Monte Carlo simulation was conducted to model the light propagation in multi-layer onion tissues in four cultivars. 3) An integrated experiment was performed on 28 bulbs to generate individually correlated data sets regarding NIR spectrometry (1000-1600 nm), chemical analysis (Brix, Pungency, LF/IS) and trained sensory panels. 4) Dielectric properties of Vidalia onions were analyzed for moisture dependence at 13.36 GHz and 23 degree for moisture content between 6% and 92%, using an open-ended coaxial-line probe connected to a network analyzer. Linear regression models were developed using the dielectric constant, dielectric loss factor, and two density-independent functions. 5) Twenty sweet onion selections were evaluated for pungency and sweetness levels by a panel of ten trained panelists over the course of eight weeks. During this time each of the twenty selections were scanned with a near infrared camera and pungency and sweetness compounds were evaluated using gas Chromatography and refractometry. Objective 2: 1) A customized SmartNose system was developed to detect rot onions in storage. 2) Several onion disease management strategies were continuously evaluated: postharvest chemical drenching, sulfur dioxide and ozone treatments in storage. 3) Detection of onions infected by sour skin in storage using zNose was investigated. Onion volatile compounds were measured by GCMS. Field studies were continuously conducted to study the effect of the double-cropping system. 4) Onions with control and IPM treatments were continuously harvested and evaluated regarding the incident of Botrytis neck rot and Bacterial soft rot in Colorado and Idaho. Objective 3: the anaerobic digester system was continuously improved. The effect of alkalinity on gas production was studied. Objective 4: Focused group interviews were conducted for Vidalia onion producers. Objective 5: Numerous graduate students were recruited to actively work on this project. Presentations have been made in various venues such as the National Allium Research Conference, the American Society of Biological and Agricultural Engineers (ASABE), the National Onion Association Conference, Southeastern Region Fruit and Vegetable Conference, Extension trainings, and production meeting. A website of this project (alliumnet.com) was regularly visited by our stakeholders. PARTICIPANTS: Project PIs: University of Georgia: Changying Li (College of Engineering), Ron Gitaitis (Plant Pathology), Gary Hawkins (Crop and Soil Sciences), George Boyhan (Horticulture), Robert Shewfelt (Food Science), Chi Thai (College of Engineering), William Tollner (College of Engineering); Colorado State University: Howard Schwartz (Plant Pathology); University of Idaho: Krishna Mohan (Plant Pathology); Mississippi State University: Kimberly Morgan (Ag Economics); Auburn University: Joseph Molnar (Ag Econ & Rural Sociology). Project cooperators: Cornell University: Christy Hoepting (Extension Vegetable Specialist); Utah State University: Claudia Nischwitz (Plant Pathologist); Tsinghua University: Xianting Li, Hao Cai (Engineers); University of Georgia: David Langston (Extension Vegetable Disease Specialist); Georgia Southern University: Norman Schmidt (Chemist), USDA-ARS: Samir Trabelsi (scientist at the Russell Laboratory in Athens). Training/professional development: Weilin Wang (MS/Ph.D. student, UGA), Tharun Konduru (MS student, UGA), Haihua Wang (visiting Ph.D. student, UGA), Anna Watson (MS/Ph.D. student, UGA), Antoinette Menuel (MS student, UGA), Sean McKeown (MS student, UGA), Xiaoliang Shao (PhD student, Tsinghua), Manish Bansal (MS student, UGA), Jolene Glenn (MS student, Auburn), Stephanie Szostek (MS student, Colorado State), Anne Morrison (technician, UGA), Katherine Robbins (graduate assistant, UGA), Anthony Bateman (Research Professional, UGA), Hunt Sanders (Pathology, UGA), Rajagopalbabu Srinivasan (Entomology, UGA), David Riley (Entomology, UGA), Randy Hill (VOVRC Superintendent, UGA), Denny Thigpen (Research Technician, UGA), Reid Torrance (UGA Area Onion Agent), Kris Otto and Mark McMillan (Research Technicians, Colorado State). TARGET AUDIENCES: The primary target audience for this project consists of commercial onion growers, processors in the southeast, northwest, southwest, and northeast regions of the United States. Knowledge transfer has occurred in educational sessions at the National Allium Research Conference, National Onion Association Meetings, the Southeast Fruit and Vegetable Conference, County agent trainings and production meetings. The project website has been visited regularly by stakeholders with more than 2000 hits per month. PROJECT MODIFICATIONS: Nothing significant to report during this reporting period.

Impacts
Objective 1: 1) The optical property test we have conducted is the first effort in the literature to understand the fundamental optical properties of the onion tissue. Our data suggested that onion dry skins should be handled properly in optical measurements since they can significantly affect the light propagation. The results of this study can be used to develop appropriate optical techniques to improve quality control of onions. 2) Samples of onions measured from different years, varieties, and locations showed no significant differences in the dielectric properties. This follows the trend that microwave moisture measurement is type, variety, and location independent. Current data suggested that use of a density-independent function was more effective in prediction of moisture content than using dielectric properties alone. The measurements and models presented in this paper constitute the foundation for the development of a sensor for determining the degree of curing an onion has undergone. Objective 2: 1) Our data suggested that postharvest drench treatments with fungicide improved storability, especially when heat curing was not used. Use of copper based compounds as postharvest drenches did not improve storability of onions. 2) Detection of onion volatiles from infected onions could be distinguished from healthy onions at 50% or 10%, infection in a small volume (< 2 L3) container, however with an infection rate of only 1% in a closed room (~11,000 L3), early analysis indicates a distinct profile could not be detected from infected onions. Double-cropping study showed consistent results with the data in previous years: the highest marketable yield was in onions double-cropped behind pearl millet. Objective 3: Data collected indicates that at low and high organic loading rates (even without alkalinity additions) the digesters were able to produce inherent alkalinity. Initial data indicates that at organic loading rates at or close to 2.0 alkalinity production can occur within the digester. This internal alkalinity production reduces the need for additions of alkalinity thereby reducing an additional cost to the operator. Test will continue to increase the organic loading rate at both mixture ratios to find the optimum organic loading rate for onion waste. Objective 4: The consumer panel preferred selections with low pungency/ high sweetness and high pungency/ high sweetness indicating that the level of sweetness was more important than pungency. Using a standard triangle test the panel was unable to detect a difference between those samples scanned by X-ray from those that were not scanned. Objective 5: The project has provided training and working opportunities for numerous students and other personnel. The presentations and visits to farmers and processors helped engage stakeholders. The website of this project archives technical documents and meeting minutes of this project and disseminates knowledge developed out of this project. Regular visits to this website exceed 2000 per month.

Publications

  • Menuel, A. 2011. Palate Cleanser effectiveness in evaluating sweetness, bitterness, and pungency of sweet onions and sensory, chemical and instrumental techniques. MS Thesis, University of Georgia.
  • Manish Bansal. 2012. Onion postharvest treatment to inhibit diseases. MS Thesis, University of Georgia.
  • Wang, Haihua. 2012. Developing hyperspectral imaging technologies for onion postharvest quality prediction. Doctoral Dissertation, China Agricultural University.
  • Hawkins, G.L. 2012. Using Onion Waste as a Co-digestant with Dairy Waste to Produce a Renewable Energy. Published in the 2012 Vidalia Onion Research and Extension Report, Ed. Stephen W. Mullis, UGA.
  • Wang, W., C. Li, W. Tollner and G. Rains. 2012. Development of software for spectral imaging data acquisition using LabVIEW. Computers and Electronics in Agriculture. 84: 68-75.
  • Wang, H., C. Li, M. Wang. 2012. Onion Internal Quality Prediction Using a Near Infrared Hyperspectral Imaging System. ASABE paper No. 121341135. Dallas, Texas, July 29-August 1, 2012.
  • Wang, W. C. Li, R. Gitaitis, W. Tollner. 2012. Optical Properties of Healthy and Sour Skin-infected Onion Tissues in Vis-NIR Region. ASABE paper No. 121338380. Dallas, Texas, July 29-August 1, 2012.
  • Wang, W., C. Li, W. Tollner, R. Gitaitis, G. Rains. 2012. Design and Calibration of Liquid Crystal Tunable Filter Based Spectral Imaging System. ASABE paper No. 1338382. Dallas, Texas, July 29-August 1, 2012.
  • Konduru, T., C. Li, G. Rains. 2012. Development of A Customized Gas Sensor Array for Postharvest Disease Detection in Onions During Storage. ASABE paper No. 121337633. Dallas, Texas, July 29-August 1, 2012.


Progress 09/01/10 to 08/31/11

Outputs
OUTPUTS: Objective 1: 1) A line scan hyperspectral imaging system was developed to predict onion internal quality attributes (dry matter content, soluble solid content, and firmness). Three sampling modes (reflectance, interactance, and transmittance) were investigated. 2) A preliminary study was done to measure optical properties of onions using a laser (632.8 nm) and an integrating sphere system. The absorption and reduced scattering coefficients and light penetration depths were estimated using the inverse adding-doubling method. 3) A custom Genetic Algorithm based tool was created to correlate spectral data with the scores from a sensory panel and chemical data for sweetness, bitterness and pungency. 4) Dielectric properties of onions were measured using microwave sensing at different moisture contents (6-92%) and different temperatures in the range from 200 MHz to 15 GHz. 5) The effects of four palate cleansers at detecting sweetness, bitterness and pungency in sweet onions were studied. Consumer and sensory tests were conducted to evaluate onion sensory attributes. Objective 2: 1) A customized electronic nose system is being developed to detect rot onions in storage. 2) Several onion disease management strategies were evaluated: postharvest chemical drenching, sulfur dioxide and ozone treatments in storage, and preharvest double-cropping and crop rotation. 3) A semi-selective medium (SSM) was developed to quantify populations of Burkholderia cepacia, causal agent of sour skin. 4) Onions with control and IPM treatments were harvested and evaluated regarding the incident of Botrytis neck rot and Bacterial soft rot in Colorado and Idaho. Objective 3: The anaerobic digester was optimized for its operating parameters. Two mixture ratios (50/50 and 75/25) between the onion and dairy waste were investigated. The feed rate and the effect of alkalinity in gas production were also optimized. Objective 4: Onion industry member questionnaires are being developed. Literature review on economic threshold model development is being conducted. Objective 5: Numerous graduate students were recruited to actively work on this project. Presentations have been made in various venues such as the National Allium Research Conference (December, 2010), the National Onion Association Conference (July, 2011), Southeastern Region Fruit and Vegetable Conference (January, 2011), Extension trainings, and production meeting. A website of this project (alliumnet.com) was regularly visited by our stakeholders. PARTICIPANTS: Project PIs: University of Georgia: Changying Li (Biological & Agricultural Engineering), Ron Gitaitis (Plant Pathology), Gary Hawkins (Biological & Agricultural Engineering), Dan MacLean (Horticulture), Robert Shewfelt (Food Science), Chi Thai (Biological & Agricultural Engineering), William Tollner (Biological & Agricultural Engineering); Colorado State University: Howard Schwartz (Plant Pathology); University of Idaho: Krishna Mohan (Plant Pathology); Mississippi State University: Kimberly Morgan (Ag Economics); Auburn University: Joseph Molnar (Ag Econ & Rural Sociology). Project cooperators: Cornell University: Christy Hoepting (Extension Vegetable Specialist); Utah State University: Claudia Nischwitz (Plant Pathologist); Tsinghua University: Xianting Li, Hao Cai (Engineers); University of Georgia: David Langston (Extension Vegetable Disease Specialist); Georgia Southern University: Norman Schmidt (Chemist), USDA-ARS: Samir Trabelsi (scientist at the Russell Laboratory in Athens). Training/professional development: Weilin Wang (MS/Ph.D. student, UGA), Tharun Konduru (MS student, UGA), Haihua Wang (visiting Ph.D. student, UGA), Anna Watson (MS/Ph.D. student, UGA), Antoinette Menuel (MS student, UGA), Sean McKeown (MS student, UGA), Xiaoliang Shao (PhD student, Tsinghua), Manish Bansal (MS student, UGA), Jolene Glenn (MS student, Auburn), Stephanie Szostek (MS student, Colorado State), Anne Morrison (technician, UGA), Katherine Robbins (graduate assistant, UGA), Anthony Bateman (Research Professional, UGA), Hunt Sanders (Pathology, UGA), Rajagopalbabu Srinivasan (Entomology, UGA), David Riley (Entomology, UGA), Randy Hill (VOVRC Superintendent, UGA), Denny Thigpen (Research Technician, UGA), Reid Torrance (UGA Area Onion Agent), Kris Otto and Mark McMillan (Research Technicians, Colorado State). TARGET AUDIENCES: The primary target audience for this project consists of commercial onion growers, processors in the southeast, northwest, southwest, and northeast regions of the United States. Knowledge transfer has occurred in educational sessions at the National Allium Research Conference, National Onion Association Meetings, the Southeast Fruit and Vegetable Conference, County agent trainings and production meetings. The project website has been visited regularly by stakeholders with more than 2000 hits per month. PROJECT MODIFICATIONS: Not relevant to this project.

Impacts
Objective 1: 1) For the first time, we proved the efficacy of the hyperspectral imaging technique for onion internal quality prediction. Among the three quality properties, SSC and DM can be better predicted than firmness. Among the three sampling modes, interactance was consistently better than reflectance in predicting onion internal quality. 2) Optical property tests showed that both the outer dry skin and internal flesh scale of onions are high albedo medium. The estimated light penetration depths in onion tissues suggested that the red light would be highly scattered and absorbed in onion dry skin. Measuring optical properties of onions is important for developing appropriate optical sensing approaches to test onion qualities. 3) It was challenging to predict human sensory scores based on spectral data due to substantial variations among panelists. Onion chemical data can be better modeled by GA tool using only two wavelengths. 4) Use of a density-independent function that incorporates both the dielectric constant and loss factor enabled prediction of moisture content with extremely high accuracy up to 40% moisture content. Microwave sensing offers an opportunity to determine nondestructively the amount of moisture in the onion by sensing its dielectric properties. Objective 2: 1) Experiments showed that most of the fungicide treatments had an effect on retarding Botrytis neck rot. A similar effect was also observed in sour skin. 2) Although the modified SSM (mSSM) increased selectivity for use with Georgia soils, there remained the problem of too high of a count of non-virulent B. cepacia - like colonies. More work is underway. Objective 3: Data collected indicates that at low and high organic loading rates (even without alkalinity additions) the digesters were able to produce inherent alkalinity. Initial data indicates that at organic loading rates at or close to 2.0 alkalinity production can occur within the digester. This internal alkalinity production reduces the need for additions of alkalinity thereby reducing an additional cost to the operator. Test will continue to increase the organic loading rate at both mixture ratios to find the optimum organic loading rate for onion waste. Objective 4: A survey was conducted and found 78% consumers would be willing to consume onions that were X-rayed to ensure quality with 15% unwilling and 7% unsure. Younger consumers seemed to be more concerned about X-ray screening of onions than older consumers. Objective 5: The project has provided training and working opportunities for numerous students and other personnel. The presentations and visits to farmers and processors helped engage stakeholders. The website of this project archives technical documents and meeting minutes of this project and disseminates knowledge developed out of this project. Regular visits to this website exceed 2000 per month.

Publications

  • Schwartz, H. F. 2011 (Revised). Botrytis, downy mildew and purple blotch of onion. 4 pages. CSU Fact Sheet no. 2.941.
  • Du Toit, L.J., and Schwartz, H.F. 2011.Storage Fungal Diseases.
  • Mohan, S.R., Hausbeck, and Tisserat, N.A. 2011. Foliar Fungal Diseases.
  • Schwartz, H.F. 2011. Storm Damaged Onions.
  • Schwartz, H.F., and Cramer, C.S. 2011. Bulb Growth Stages of Onion.
  • Hawkins, G.L. 2010. Extracting Energy from Poultry Waste and Fruit and Vegetable Waste. Presentation at NRCS Regional Training. Tifton, GA 2 November 2010.
  • Hawkins, G.L.; C. Li; H. Schwartz; K. Mohan; J. Molnar; K. Morgan; E.W. Tollner; C. Thai; D. MacLean; R. Gitaitis; R. Shewfelt. 2010. Converting Onion Waste into Useful Energy. Presentation at 2010 National Allium Research Conference. 9 December 2010. Reno, NV.
  • Hawkins, G.L.; C. Li; H. Schwartz; K. Mohan; J. Molnar; K. Morgan; E.W. Tollner; C. Thai; D. MacLean; R. Gitaitis; R. Shewfelt. 2011. Update on Onion Waste Objective of Project. 2011 USDA-SCRI Annual Meeting. 8 January 2011, Savannah, GA. 15 people.
  • Hawkins, G.L. 2010. Innovative Tools and Best Practices for Regenerating Small Scale On Farm energy Projects. Presentation at 2010 Growing Powers National-International Urban and Small Farm conference. Milwaukee, WI. 10 September 2010.
  • Hawkins, G.L.; C. Li; H. Schwartz; K. Mohan; J. Molnar; K. Morgan; E.W. Tollner; C. Thai; D. MacLean; R. Gitaitis; R. Shewfelt. 2011. Converting the Sweet Onion into an Odorless Gas. Presentation at 2011 SE Regional Fruit and Vegetable Conference. Savannah, GA. 8 January 2011. 60 people.
  • Hawkins, G.L. 2011. 7 Ways to Manage Fruit and Vegetable Waste. Presentation at 2011 SE Regional Fruit and Vegetable Conference. Savannah, GA. 8 January 2011. 60 people.
  • Hawkins, G.L. 2011. Anaerobic and Solar Power Projects at UGA. Presentation for Congressional Representatives on the UGA Tifton Campus. 26 April 2011. 12 persons.
  • Wang, W., C. Li, B. Tollner, R. Gitaitis, and G. Rains. 2011. Measuring Absorption and Scattering Properties of Onions at 632 nm using Inverse Adding Doubling Method. ASABE Paper No. 1110722. Louisville, Kentucky, August 8-10, 2011.
  • Wang, H. C. Li, M. Wang. 2011. Onion Internal Quality Prediction using Line-scan Hyperspectral Imaging. ASABE Paper No. 1110708. Louisville, Kentucky, August 8-10, 2011.
  • C. Li. 2011. Sensing and Automation for Specialty Crops in Georgia. USDA W-1009 Multi-state Project Meeting. Honolulu, Hawaii. June 16, 2011.
  • C. Li. 2011. SCRI: Advancing Onion Postharvest Handling Efficiency and Sustainability by Automated Sorting, Disease Control, and Waste Stream Management. Southeast Regional Fruits and Vegetable Conference. Savannah, GA. January 6-8, 2011.
  • Watson, A., R. Gitaitis, and C. Li. 2010. Detection of Sour Skin of Onion, Caused by Burkholderia cepacia, using zNose Technology. Poster presentation at National Allium Research Conference. Reno, Nevada, December 8-10, 2010. (this poster was the winner of the First Prize of the Graduate Student Poster Competition)
  • Hawkins, G.L.; J. Worley, G. Rains, J.E. Smith, C. Li, E.W. Tollner, C. Thai, H. Schwartz, K. Mohan, J. Molnar, K. Morgan, D. MacLean, R. Gitatis, R. Shewfelt. 2011. Co-digestion of Fruit and Vegetable Waste to Better Manage and Use Waste Products. Presentation at 2011 ASABE International Meeting, Louisville, KY, 10 August 2011.
  • Hawkins, G.L. 2011. Advanced Biofuels Processing. Presentation at Southwest District Agricultural Agent Training. UGA Tifton Campus. 15 November 2011. 35 persons.
  • Bansal, M., D. MacLean, H. Sanders, R. Gitaitis, and A. Bateman. 2011. Evaluation of postharvest application of fungicide towards minimizing postharvest losses of Vidalia Onions. Poster presentation at ASHS conference (23-28 Sep, 2011) at Big Island, Kona, Hawaii.
  • McKeown, M.S., S. Trabelsi and E.W. Tollner. 2012. Dielectric spectroscopy measurements for moisture prediction in Vidalia onions. Transactions of the ASABE (Accepted).
  • Morgan, K.L. 2011. Key Concepts Influencing Technology Adoption: Interviews with U.S. Specialty Crops Supply Chain Participants. Selected paper presented at 2011 Food Distribution Research Society Annual Conference, Portland, OR.
  • Wang, W., C. Li, W. Tollner, G. Rains and R. Gitaitis. 2011. Shortwave Infrared Hyperspectral Imaging for Detecting Sour Skin (Burkholderia Cepacia)-Infected Onions. Journal of Food Engineering. DOI: 10.1016/j.jfoodeng.2011.10.001.
  • Wang, W., C. Li, W. Tollner, G. Rains, R. Gitaitis. 2011. A liquid crystal tunable filter based shortwave infrared spectral imaging system for food quality and safety inspection: design and integration. Computers and Electronics in Agriculture. DOI: 10.1016/j.compag.2011.07.012.
  • Wang, W., C. Li, W. Tollner, G. Rains and R. Gitaitis. 2011. Development of an LCTF-based shortwave infrared spectral imaging system for food quality and safety inspection: calibration and characterization. Computers and Electronics in Agriculture. DOI: 10.1016/j.compag.2011.09.003.


Progress 09/01/09 to 08/31/10

Outputs
OUTPUTS: Objective 1: 1) A liquid crystal tunable filter based short wave infrared hyperspectral imaging system was developed for onion quality inspection and disease detection. The HIS system was fully calibrated and characterized in its spatial resolution and spectral accuracy. A hyperspectral image acquisition software was developed in the LabVIEW environment. This hyperspectal imaging system was used for sour skin detection in onions. 2) A large aperture spectrometry was developed to predict human sensory perceptions of sweetness, pungency and bitterness using NIR transmittance spectra in the 1000-2200 nm range. A total of 22 varieties of onions were evaluated by both the spectrometry technique and a sensor panel. 3) A new sensing modality using microwaves for moisture detection and better controlling the curing of onions is being actively investigated. Preliminary sensor designs are being evaluated by simulation modeling. Objective 2: 1) The Dynamic Test Method of Source Identification was proposed to identify the location and strengths of rot onions in storage. The number and locations of ideal gas sensors were optimized and real gas sensors were further simulated by considering missing data, random errors and unknown releasing time of contaminant. 2) A portable gas chromatograph was explored as a new approach for the rapid detection of sour skin in stored onions with 10 different strains of B. cepacia. 3) The following onion disease management strategies were explored: postharvest chemical drenching, sulfur dioxide and ozone treatments in storage, double-cropping onions behind pearl millet (Pennisetum glaucum) or corn (Zea mays), and late season pre-harvest practices using bactericide and fungicide. 4) Five varieties of onions with control and IPM treatments were harvested and evaluated regarding the incident of Botrytis neck rot and Bacterial soft rot in Colorado and Idaho. Objective 3: Onions from Georgia, New York and Colorado were tested for pH, COD, alkalinity, brix, moisture content and ash content. A screwpress has been installed to separate onion juice from pulp for use in anaerobic digesters. Digesters have been designed and installed and are in the initial stages of receiving onion juice. Objective 4: Extension research has been done on the onion industry which included onion production practices, onion growing area-specific budgets, historical input and market prices for each project state, review of Federal Marketing Order programs, and onion industry websites and university extension and research publications. Literature review was completed concerning those factors affecting producer willingness to adopt new technologies in related specialty crop industries. Objective 5: Numerous graduate students were recruited to actively work on this project. Presentations have been made in various venues such as the National Allium Research Conference, the National Onion Association Conference, the Association of Natural Resource Extension Professionals, Southeastern Region Fruit and Vegetable Conference, Extension trainings, and production meeting. A website of this project was activated at the alliumnet.com to promote our SCRI Project. PARTICIPANTS: Project PIs: University of Georgia: Changying Li (Biological & Agricultural Engineering), Ron Gitaitis (Plant Pathology), Gary Hawkins (Biological & Agricultural Engineering), Dan MacLean (Horticulture), Robert Shewfelt (Food Science), Chi Thai (Biological & Agricultural Engineering), William Tollner (Biological & Agricultural Engineering); Colorado State University: Howard Schwartz (Plant Pathology); University of Idaho: Krishna Mohan (Plant Pathology); Mississippi State University: Kimberly Morgan (Ag Economics); Auburn University: Joseph Molnar (Ag Econ & Rural Sociology). Project cooperators: Cornell University: Christy Hoepting (Extension Vegetable Specialist); Utah State University: Claudia Nischwitz (Plant Pathologist); Tsinghua University: Xianting Li, Hao Cai (Engineers); University of Georgia: David Langston (Extension Vegetable Disease Specialist); Georgia Southern University: Norman Schmidt (Chemist), USDA-ARS: Samir Trabelsi (scientist at the Russell Laboratory in Athens). Training/professional development: Weilin Wang (MS student, UGA), Xuewei Qi (PhD student, UGA), Haihua Wang (visiting Ph.D. student, UGA), Anna Watson (MS student, UGA), Antoinette Menuel (MS student, UGA), Sean McKeown (MS student, UGA), Xiaoliang Shao (PhD student, Tsinghua), Manish Bansal (MS student, UGA), Jolene Glenn (MS student, Auburn), Stephanie Szostek (MS student, Colorado State), Anne Morrison (technician, UGA), Katherine Robbins (graduate assistant, UGA), Anthony Bateman (Research Professional, UGA), Hunt Sanders (Pathology, UGA), Rajagopalbabu Srinivasan (Entomology, UGA), David Riley (Entomology, UGA), Randy Hill (VOVRC Superintendent, UGA), Denny Thigpen (Research Technician, UGA), Reid Torrance (UGA Area Onion Agent), Kris Otto and Mark McMillan (Research Technicians, Colorado State). TARGET AUDIENCES: The primary target audience for this project consists of commercial onion growers, processors in the southeast, northwest, southwest, and northeast regions of the United States. Knowledge transfer has occurred in educational sessions at the National Allium Research Conference, National Onion Association Meetings, the Southeast Fruit and Vegetable Conference, County agent trainings and production meetings. The project website has been visited regularly by stakeholders with more than 2000 hits per month. PROJECT MODIFICATIONS: Nothing significant to report during this reporting period.

Impacts
Objective 1: 1) The reflectance short wave infrared hyperspectral images can detect sour skin-infected onions effectively from day 4 to day 7 after inoculation by achieving overall classification accuracies of 80%, 85%, 95%, and 100%, respectively. Proprietary software was developed to control the imager and acquire spectral images. A Master student was trained and a M.S. thesis was generated out of this project. 2) Sensory and instrumental data is currently being analyzed to develop a predictive model for each sensory attribute. The experiment will be repeated to test the validity of the model. The model could be used to predict acceptability by consumer panelists. Objective 2: 1) Algorithms for rot onion detection in storage were developed and validated by numerical simulations. The main factors related to the performance of source identification were identified and analyzed. 2) Results indicate that the zNose can quantitatively differentiate healthy onions from onions infected with B.cepacia after 3 days of incubation. 3) Sour skin levels were significantly less in onions following pearl millet when compared to disease levels in onion following corn in soils with a long-term history of onion production. Sulfur dioxide fumigation is beneficial for reducing the incidence of botrytis. The two proprietary fungicides investigated resulted in a 40 - 60 % decrease in BNR after 4 months and 15 days at room temperature. Treatment with a postharvest fungicide offers great promise as a tool for reducing storage losses due to botrytis allii. However, much research is needed in this area before any recommendations can be made. Objective 3: Current digesters available for onion testing are 90 liters and 4000 liters. The 90 liter digesters are anaerobic filters (High Rate fixed film systems) and an anaerobic sequencing batch reactor (ASBR which is a high rate suspended sludge digester). The data from the feed rate variation and associated organic loading rate has shown that approximately 1 liter of bio-gas is being produced from a third of a liter of onion introduced to the digesters. Objective 4: A contact database was established to conduct meaningful survey research. Onion industry interviews were completed for Colorado, Idaho and Arizona in July/August 2010 and New York in September 2010. Interview findings were summarized by state and results tied to state production characteristics, marketing issues, industry concerns and priorities, and will be used to guide future survey efforts and directions. Objective 5: The project has provided training and working opportunities for numerous students and other personnel. The presentations and visits to farmers and processors helped engage stakeholders. The website of this project archives technical documents and meeting minutes of this project and disseminates knowledge developed out of this project. Regular visits to this website exceed 2000 per month.

Publications

  • 9)Wang, W., C. Thai, C. Li, R. Gitaitis, W. Tollner. 2009. Detection of sour skin diseases in Vidalia sweet onions using near-infrared hyperspectral imaging. ASABE Paper No. 096364. Reno, Nevada, June 21-24, 2009.
  • 10)MacLean, D. Bansal, M., Sanders, F.H. Jr., Gitaitis, R., Bateman, A., Hill, R., Thigpen, D. 2010. Postharvest fungicide drench test for control of Botrytis during storage. Poster presentation at the National Allium Research Conference, Reno, NV. December 8-10, 2010.
  • 11)Bansal, M., MacLean, D., Bateman, A. 2010. The effect of storage atmosphere on flavonoid content and antioxidant capacity of Vidalia Sweet onion. Poster presentation at the National Allium Research Conference, Reno, NV. December 8-10, 2010.
  • 12)MacLean, D., Sanders, F.H., Gitaitis, R., Bansal, M., Bateman, A., Hill, R., Thigpen, D. 2010. Postharvest Fungicide Drench Test for Control of Botrytis During Storage. Georgia Onion Research-Extension Report, No. 3-2010: 33-37.
  • 13)Srinivasan, R., MacLean, D., Gitaitis, R., Riley, D. 2010. Evaluation of Late Season Pre-Harvest Practices Towards Minimizing Postharvest Losses in Vidalia Onions. Georgia Onion Research-Extension Report, No. 3-2010: 43-49.
  • 14)MacLean, D., Bateman, A., Bansal, M., Torrance, R., Hill, R., Thigpen, D. 2010. Sulfur Dioxide and Ozone Treatments for the Postharvest Control of Onion Botrytis. Georgia Onion Research-Extension Report, No. 3-2010: 66-70.
  • 15)Hawkins, G.L. 2010. Managing Fruit and Vegetable Waste. UGA Extension Publication number C988.
  • 1)Li, C., H. Schwartz, K. Mohan, J. Molnar, K. Morgan, R. Gitaitis, G. Hawkins, D. MacLean, R. Shewfelt, C. Thai, W. Tollner. 2010. Specialty Crop Research Initiative Project: Advance onion postharvest handling efficiency and sustainability through multidisciplinary approach. Invited lecturer presentation at the National Allium Research Conference, Reno, NV. December 8-10, 2010.
  • 2)Li, C., R. Gitaitis, and N. Schmidt. 2010. Detection of onion postharvest diseases by analyses of headspace volatiles using a gas sensor array and GC-MS. LWT - Food Science and Technology. In press.
  • 3)Li, C., H. Schwartz, K. Mohan, J. Molnar, K. Morgan, R. Gitaitis, G. Hawkins, D. MacLean, R. Shewfelt, C. Thai, W. Tollner. 2010. Holistic approach to advance onion postharvest handling efficiency and sustainability. Invited poster presentation at ASHS annual meeting. Palm Desert, California, August 1-3, 2010.
  • 4)Li, C., Gitaitis, R. D., Tollner, E. W., Sumner, P. E., Maclean, D. D. 2009. Evaluation of an electronic nose for sour skin detection in Vidalia onions. University of Georgia Onion Research Extension Report. UGA/CPES Research-Extension Publication No. 3. Pages 36-40.
  • 5)Wang, W., Li, C., Thai, C., Gitaitis, R., Tollner, B. 2009. Sour Skin Detection in Vidalia Onions Using Hyperspectral Imaging. Georgia Vegetable Research and Extension Report 2008-2009. UGA/CPES Research-Extension Publication No. 5. Pages 1-4.
  • 6)Wang, W., C. Li, E.W. Tollner, R. Gitaitis, G. Rains, S. Yong. 2010. Near-infrared Hyperspectral Reflectance Imaging for Early Detection of Sour Skin Disease in Vidalia Sweet Onions. ASABE Paper No. 1009106. Pittsburgh, Pennsylvania, June 20-23, 2010.
  • 7)Wang, W., C. Li, R. Gitaitis, G. Rains, C. Thai, E.W. Tollner. A Near-infrared Hyperspectral Imaging System for Quality Inspection of Specialty Crops. Poster. Southeast Regional Fruits and Vegetable Conference. Savannah, GA. January 7-10, 2010.
  • 8)Li, C., R. Gitaitis, E.W. Tollner, P. Sumner, and D. MacLean. 2009. Onion Sour Skin Detection Using a Gas Sensor Array and Support Vector Machine. Sensing and Instrumentation for Food Quality and Safety 3(4): 193-202.