Location: Peanut Research
Title: Storing Peanuts in Flexible Hermetically Sealed Containers Author
Submitted to: Proceedings of the American Society of Agricultural and Biological Engineers International (ASABE)
Publication Type: Proceedings
Publication Acceptance Date: February 15, 2008
Publication Date: June 15, 2008
Citation: Butts, C.L. 2008. Storing Peanuts in Flexible Hermetically Sealed Containers. Proceedings of the American Society of Agricultural and Biological Engineers International (ASABE). Interpretive Summary: Peanuts are typically stored in large bulk facilities capable of holding 2000 to 10,000 tons. With a recent interest in producing peanuts as an energy crop, growers have a need for storing peanuts on-farm until they can be cleaned, shelled, and crushed for oil. Small grains such as rice, wheat, soy beans, and corn have been successfully stored in hermetically sealed grain bags. Peanuts were placed in six bulk bags or totes that held 1000 lb of in-shell peanuts each. The totes were then placed in the large grain bag and sealed. During a 6-month storage period from 06 Oct 2006 to 04 Apr 2007, the oxygen level decreased from 21% to 11% inside the grain bag. When peanuts were removed, there was no change in weight of the peanuts and seed germination levels averaged 96%. The value of the peanuts, which is based on the kernel size distribution, decreased approximately 9% during the storage period.
Technical Abstract: In-shell peanuts stored in large bulk warehouses lose approximately 1.5-2% of their value. However, peanuts stored as long as nine months may lose as much as 5% of their value due to excessive moisture loss, a reduction of peanut kernel size and damage due to insects or microbial growth. Research has been conducted investigating the use of controlled atmospheres for bulk storage, however, difficulties occur due to moisture migration within the large bulk of peanuts. Hermetic storage bags are commercially available that when sealed are impervious to gas exchange. Tests were conducted by placing six woven polypropylene totes, each filled with approximately 500 kg of in-shell peanuts, in the hermetic storage bag. Oxygen level was monitored periodically using a hand-held air sampling unit and oxygen sensor. Temperature was monitored in each tote throughout the storage period. Peanuts were stored from 06 Oct 2006 until 04 Apr 2007. Tests for the 2007 crop were underway at the time of submission. Peanut quality was determined before and after storage by measuring moisture content, kernel size distribution, aflatoxin contamination, and seed germination. Oxygen levels reached a minimum of 11% and were higher than the 5% or less reported in other storage of other commodities. This was due to the low initial peanut moisture content of 6% and minimal insect infestation. Wet, germinated peanuts were observed in the top of each tote probably due to moisture migration. No detectable change in the mass of peanuts was observed during storage. Total value of the peanuts stored in the hermitic storage container decreased approximately 9% due to changes in the size distribution of peanut kernels. Seed viability was excellent following storage as indicated by an average 96% germination. Tests using the 2007 peanut crop will be presented as well.