Alternative Storage Environments for Shelled Peanuts

• Published in: Peanut science 2017-07, Vol.44 (2), p.111-123
• Main Authors: Butts, C.L., Lamb, M.C., Sorensen, R.B., Powell, S., Cowart, D., Horm, K., Anthony, B., Bennett, J.
• Format: Article
• Language: English
• Subjects: Cold storage; Eggs; Fatty acids; Flavor; Germination; Hatches; Humidity; Infestation; Legumes; Moisture; Moisture content; Nuts; Peanuts; Peroxide; Relative humidity; Seed germination; Sensory evaluation; Storage facilities
• ISSN: 0095-3679; 1943-7668
• DOI: 10.3146/PS17-2.1

Studies were conducted in small chambers and commercial storage facilities to evaluate the effect of storing shelled peanuts at 3, 13, and 21 C (38, 55, 70 F) for one year. Shelled medium runner peanuts from the 2014 crop were placed in the three different environments in Feb 2015, sampled at 60-d intervals until Feb 2016 (364 days). Difficulty maintaining the desired relative humidity of 65% in the 3 C unit, led to unacceptable mold growth and severely degraded seed germination. Peanuts stored at 21 C developed an infestation of Indian meal moth after 238 d in storage rendering the samples unsuitable for sensory analysis from that point forward. The infestation most likely occurred due to hatches of eggs that were present in the original samples. Sensory analyses showed very little change in the intensity of the Roasted Peanut flavor characteristic in either storage environments. There were no unacceptable increases in free fatty acids or peroxide values during the 1-yr storage period for peanuts stored at 13 C. The percent free fatty acids in peanuts stored at 13 C remained well below 1% throughout the 1-yr study. Commercial studies were conducted from Feb 2015 through Mar 2016. Six 60-d runs were conducted where three totes of medium runner peanuts from the same manufacturing lot were placed in commercial cold storage facilities maintained at 3 and 13 C. There were no differences in the initial moisture content of peanuts when placed in the two storage environments. However, after 30 and 60-d storage, the peanuts stored at 13 C tended to be an average of 0.3% dryer than those stored at 3 C. The peanuts had the highest increase in moisture between June and August 2015, with the moisture content after 30 and 60 d storage at 3 C averaged 8.1 and 7.7%, respectively. The peanuts stored in the 13 C environment averaged 7.6 and 7.3% moisture content after 30 and 60 d in storage, respectively. This study has shown that shelled peanuts can be stored for up to one year with no detrimental effects at temperatures up to 13 C and relative humidity ranging from 55 to 70%. Based on this research, the recommended temperature for storing shelled peanuts can be increased to 13 C, while maintaining the relative humidity between 55 and 70%.