Liofilização, uma alternativa promissora para a conservação de sementes de Coffea Arabica L.

Abstract

The preservation of coffee seeds still represents a major challenge for coffee farming due to the loss of their physiological quality after six to eight months of storage. This characteristic is related to the sensitivity of the seeds to desiccation. Coffea arabica L. seeds are classified as intermediate because they do not tolerate low water content. In this context, freeze-drying emerges as an alternative by promoting water removal through sublimation at low temperatures and under vacuum, preserving cellular structures and metabolic functions for prolonged periods. The objective of this study was to evaluate the survival of Arabica coffee seeds after freeze-drying and storage at room temperature. In a first experiment, seeds of the cultivar MGS Paraíso 2 were dried on silica gel or suspended sieves to water contents of 35, 30, 25, 20, 15, and 12% (wet basis) and subsequently freeze-dried to approximately 5% moisture (wt). Physiological quality was evaluated by germination, tetrazolium, and electrical conductivity tests. In a second experiment, the performance of freeze-dried seeds was evaluated using the same tests during nine months of storage after drying on silica gel or suspended sieves to the moisture levels mentioned above. Freeze-drying compromised the formation of normal seedlings in freeze-dried and pre-dried seeds between 35% and 12% moisture, while viability was not affected at moisture levels of 15% and 20%. After nine months of storage without temperature control, more than 80% of the freeze-dried seeds with 12% moisture remained viable and with a high percentage of root protrusion.