Location: National Peanut Research Laboratory
2020 Annual Report
Objectives
Objective 1: Establish new commercial equipment/methods to reduce labor and time to accurately sample farmers stock and shelled peanut lots and accurately determine peanut quality parameters including, but not limited to, foreign material, damage, oil chemistry, and kernel size distribution.
Sub-objective 1.A. Establish new sampling plans and equipment to obtain representative samples of consistent size from semi-drying trailer loads of farmers stock peanuts.
Sub-objective 1.B. Develop instrumentation systems combining the radio frequency dielectric with spectral properties to measure total oil content and the relative proportions of the oleic and linoleic fatty acids.
Objective 2: Enable use of existing and develop new commercial peanut curing (drying and processing) systems to reduce non-uniformity of moisture in farmers stock and shelled peanuts, and extend quality during storage and transport.
Objective 3: Enable new commercial uses of shelled-peanut bulk packaging and storage systems, utilizing temperature/relative humidity/oxygen modified atmospheres, to control mold and insect damage.
Approach
In a globally competitive market, the United States peanut industry must closely monitor and reduce the costs of producing, marketing, and processing peanuts for the global consumer. Peanut quality and safety are paramount and require considerable labor and capital to ensure that a safe, high quality product is delivered to the intended customer. This project is not limited to a single aspect of handling and processing peanuts, but examines peanut handling and processing on the farm to delivery of raw product to the manufacturer. The overall goal of this project is to reduce the post-harvest processing costs which include the cost of measuring and monitoring quality, quality degradation, and physical loss of product. Specifically, the objectives include: 1) Establish new commercial equipment/methods to reduce labor and time to accurately sample farmers stock and shelled peanut lots and accurately determine peanut quality, 2) Enable use of existing and develop new commercial peanut curing (drying and processing) systems to reduce non-uniformity of moisture in farmers stock and shelled peanuts, 3) Enable new commercial uses of shelled-peanut bulk packaging and storage systems, utilizing temperature/relative humidity/oxygen modified atmospheres.
Progress Report
FY2020 concludes this 5-year research project. A prototype automated pneumatic sampler for obtaining representative samples using existing sampling patterns was tested during the 2019 peanut harvest at a commercial facility with minimal intervention by ARS personnel from Dawson, Georgia. Designs and specifications were developed and provided to USDA AMS for commercial installation. Modular system design was implemented so that the existing samplers could be modified and upgraded over multiple years to facilitate adoption. ARS researchers at Dawson, Gerogia, collaborated with stakeholders, commercial and USDA-AMS, in evaluating new equipment for grading in-shell peanuts as they arrive at the peanut shelling plant. Some of the equipment evaluated was commercially available and prototype imaging systems that utilized machine vision in the visible and near infrared spectrum to classify individual peanut kernels as damaged/undamaged, high oleic/normal oleic, and measure the moisture content of individual peanut kernels.
Models were developed to simulate the airflow through peanuts as they are dried. Modeling results were compared to published data to validate the models.
Hermetic storage project for small-scale producers, primarily in developing countries, has been completed noting that germination was adversely affected, and a non-typical mold occurred during the storage period. ARS plant pathologist from Dawson, Georgia, has identified the very slow-growing mold and duplicated its growth in the laboratory. Insect growth was eliminated by the hermetic storage.
This research has contributed to development of new equipment for shelling and processing peanut samples with the principle design adopted by commercial entities to manufacture the equipment and recommended for approval by USDA-AMS for use. The research on the automated pneumatic sampler has resulted in the sampler being approved for use by USDA-AMS for use and specifications developed for commercial entities to produce, install, and maintain the equipment. The pros and cons of hermetic storage of peanuts for small-stakeholder farmers in developing countries has been determined by the research. Research addressing the proper temperature for long-term storage of shelled peanuts was been conducted and the peanut industry adopting temperatures between 38 and 55 degrees Fahrenheit as the best management practice for peanut cold storage facilities to reduce the risk for mold and other detrimental quality changes.
Accomplishments
1. Effects of hermetic storage of shelled peanuts. Purdue Improved Crop Storage (PICS) is a hermetic storage system using two layers of an impermeable plastic bag to store grain and other commodities in developing nations to reduce losses to insects and rodents. The efficacy of the PICS system for storing shelled peanuts is unknown and ARS scientists at Dawson, Georgia, conducted a 9-month study to determine its suitability for storing shelled peanuts in developing countries. Carbon dioxide levels increased rapidly as expected in the PICS bags serving to kill any insects that may have initially been in the peanuts. Losses to insect and rodent damage was heavy in the burlap/jute bags used as the control. Some of the PICS bags were damaged by rodents. The peanuts stored in the PICS bags had reduced seed germination and a very slow-growing mold that had not been previously identified on peanuts. This work by ARS scientists at Dawson, Georgia, has demonstrated that shelled peanuts should not be stored in hermetically sealed bags at/or above 7% moisture content.
2. Guidelines for storing shelled peanuts. Once the peanut industry began shelling peanuts 12 months out the year and storing the peanuts in conventional cold storage facilities maintained at 38 degrees F, shellers received complaints from product manufacturers that shelled peanuts were arriving with mold damage in the top of the 1-ton containers. ARS engineers in Dawson, Georgia, determined that peanuts packaged during the hot, humid summer months and then placed in 38 degree cold storage was at risk of developing mold in the tops of the bulk containers. ARS engineers from Dawson, Georgia, conducted 12-month studies to compare quality changes in peanuts stored at 38, 55, and 70 degrees F. Their research showed no significant changes in peanut quality when stored at 55 degrees and 65% relative humidity. As a result of this research, the peanut industry has modified its Good Management Practices for maintaining and operating cold storage facilities to allow for storage of shelled peanuts up to 55 degrees. At least one major peanut sheller has adopted 55-degree storage for some of its facilities. A cold storage facility could reduce its energy consumption by approximately 50% just by raising the operating temperature from 38 to 55 degrees F.
3. Peanut sampler automation. Every load of peanuts that a farmer delivers for sale is sampled and graded by US Department of Agriculture, Agricultural Marketing Service (USDA AMS) to determine its quality and value. Each load is parked beneath an overhead pneumatic sampler, where a probe is positioned and inserted into the load of peanuts up to 15 times by a human operator. ARS engineers in Dawson, Georgia, designed and installed an instrumentation and control system that automatically senses the load of peanuts under the sampler, locates the trailer, and controls the sampler to probe the trailer according to the prescribed probe patterns. Tests were conducted by USDA AMS for two years and have approved the control system for installation at commercial peanut facilities for official sampling. This device reduces the reliance on seasonal labor and improves the consistency and accuracy of the sample used for determining peanut quality and value.
Review Publications
Sorensen, R.B., Butts, C.L., Lamb, M.C. 2020. X-ray technology to determine peanut maturity. Peanut Science. 47(2)38-45. https://doi.org/10.3146/PS20-2.1.
Chavarro, C., Chu, Y., Holbrook Jr, C.C., Isleib, T.G., Bertioli, D., Hovav, R., Butts, C.L., Lamb, M.C., Sorensen, R.B., Jackson, S.A., Ozias-Akins, P. 2020. Pod and seed trait QTL identification to assist breeding for peanut market preferences. Genes, Genomes, and Genomics. 10:2297-2315. https://doi.org/10.1534/g3.120.401147.
