<b>Estimative of the caffeine content in the coffe seeds based on its concentration in the leaves of the seedlings and mature plants</b> - DOI: 10.4025/actasciagron.v26i3.1819

Abstract

This work was conducted in the Iapar Experimental Station at Londrina, state of Paraná, Brazil. Leaf, fruit peel and seed samples were collected in an experimental site of Coffea Arabica cultivars Mundo Novo, Catuaí, Icatu, Sarchimor and Laurina and of Coffea canephora, cultivar robusta. The objective was to save time in the plant selection with different caffeine content with previous determination of the alkaloid in the leaf. Samples composed by the first, third, and sixth pair of leaves counted from the lateral branch in the following coffee fruit stages: initial growth, fruit filling, green formed gram and full maturation. Fruit samples were collected in the bearing stage. Part of the fruits were sown to obtain seedlings from which were colleted the first and third pair of leaves. Plant materials were dried, ground and then used for the caffeine termination. Caffeine was extracted by the hot water method and determined by spectrophotometry at 273nm. The results showed that for the both coffee species the caffeine content in the first and third pair of leaves of the seedlings increased linearly with increasing caffeine content in the seeds of the plants from the same variety in the field. Therefore, the first and the third pair of leaves of the seedlings were considered to be efficient to estimate of the caffeine content in the seeds of the mature plants. Under field conditions the first pair of leaves showed caffeine content higher than older leaves, mainly for the Coffea canephora. Coffee fruit in the maturation stage presented the lowest caffeine content in the leaves. The first pair of leaves sampled in the beginning of fruit growth was the most efficient plant material to estimate the caffeine content in the seeds as compared with the older leaves and with the more advanced time of the fruit development. The alkaloid contents were slightly lower in the fruit peel (shell + parchment) as compared with seeds. The caffeine content in the seeds increased linearly with increasing N content