+Review of Previous Work+
The period during which pecans will remain free of rancidity and other forms of spoilage varies considerably with storage conditions and other factors. Common storage periods ranging from 3 to 12 months have been reported. Wright (10) placed the common storage life at 3 to 5 months. Blackmon (1) suggested 6 months as the maximum period. Medlock (11) was able to keep them in edible condition for periods up to 12 months. The wide ranges of time as observed by the different investigators are due, no doubt, to storage conditions, variety, quality of the nuts, and seasonal variations.
Cold storage was effective in preserving pecans for periods up to 2-1/2 years. Wright (10) reported effective periods of 13 to 30 months, and Medlock (11) was able to keep them for more than 2 years. Shelled pecans did not keep as long either in common or cold storage as the unshelled nuts.
+Methods and Procedures+
Results of preliminary tests made at the Alabama Station in 1937 indicated that pecans kernels might be kept at common temperatures by drying them in an oven and storing in sealed containers, which prevents absorption of moisture from the air. Since storage tests reported by other workers did not include studies of the relationship of moisture content of kernels to their storage life, it was felt that this phase of the problem should be investigated.
Preliminary tests were made to determine suitable temperatures and periods for the drying process. Temperatures of 200 to 225°F proved to be most satisfactory. These temperatures dried the kernels quite rapidly without appreciable scorching or discoloration. The drying period was varied to give desired moisture contents for the various treatments.
Four methods of sealing the jars were used in the experiments. They were the "cold seal," "steam seal," "hot seal," and "vacuum seal."
The cold seal was accomplished by placing cool kernels in cool jars and sealing without special treatment.
By the steam seal, air was exhausted from the jars with a small blast of steam and the jars sealed immediately. Condensation of the steam resulted in a partial vacuum in the jars and a slight increase in moisture content of the kernels.
By the hot seal, hot kernels were transferred directly from the oven pans to clean, dry, hot jars, and sealed immediately. Contraction of the air as the jars cooled resulted in a partial vacuum.