Hygroscopic equilibrium and viability of angico vermelho (Anadenanthera peregrina (L.) Speng) seeds under different storage environmental conditions

The objective of this study was to evaluate the effect of different temperatures and relative humidity on stored angico (Anadenanthera peregrina) seeds, as well as to develop an equation that best represents the hygroscopic equilibrium under such conditions. Seeds were kept under 40, 59, 81 and 95% relative humidity at 10 degrees C; and under 12, 23, 34, 55, 75, 84 and 93% relative humidity at 20 degrees C. Periodically water percentages and viabilities of the seeds were tested. The representation of hygroscopic equilibrium was evaluated using different equations. The modified Oswin model best fitted the data. The average time for seeds to attain hygroscopic equilibrium varied from 15 to 69 days. The conclusions are that the Oswin mathematical model can be used to determine optimal temperature and relative humidity to attained seed hygroscopic equilibrium of angico under the conditions of this study. Temperature lower than 10 degrees C and RU around 40 a 50% are the best environment conditions for storing angico seeds. These allow for a longer time of stored seed viability.