Aiming to identify parameters of popcorn quality decreases, the effects of harvest and shelling methods, initial moisture contents, drying air temperature and storage time on the expansion capacity of the Zélia and CMS 43 cultivars were evaluated. The harvest was performed when both popcorn varieties reached moisture contents of 19% w.b. and, further, 15% w.b. Manual harvest and shelling and mechanic harvest with different speeds of the shelling cylinder were used. The product was submitted to artificial drying process in thin layers and also to natural drying. Periodically a quality pattern-test related to the popcorn expansion capacity was performed. The grain quality was significantly affected by mechanical harvest and by increase in the drying air temperature; there was no decrease on the physiological quality of the popcorn during the storage; the best values of expansion capacity, for most of the treatments, were obtained after 270 days of storage. The popcorn of Zélia variety showed superior commercial quality compared to the variety CMS 43. However, it is necessary to stress the fact that the latter is still in stage of development and genetic breeding.
grain moisture; drying temperature; storage period; expansion capacity
