Espectroscopia no infravermelho próximo para classificação de sementes de café quanto à qualidade, origem e cultivar

Abstract

There is no doubt about the importance of the coffee culture for our country, for its significant participation in the socio-economic context, creating income by exports and employing labor in the different stages of agribusiness, from cultivation to marketing. One problem in production is that the propagation of plants by cuttings made and still originated from sowing seeds. A major drawback of this method is that the coffee beans have slow and uneven germination, and low storage potential. Another problem is the characterization of a seed in relation to its cultivar because the conventional method requires much time and expertise on the seedling structures. Spectroscopy is the instrumental measurement process based on the properties of absorption and emission of electromagnetic energy in some region of the electromagnetic spectrum. In this study, we used 200 seeds of 4 different cultivars derived from three different regions. In a second step, we used 9 batches of coffee beans, 3 of high quality, with germination above 90%, 3 of medium quality, with germination between 60 and 90% and 3 batches of low quality with germination lower than 60%. Later these seeds were subjected to analysis by near infrared with the flat sides facing the source of the electromagnetic wave and the spectra obtained were analyzed with the help of chemometric methods for classification of different cultivars. A genome study with microsatellite markers was also performed. Thus, it is necessary to use the NIR and the establishment of chemometric models to predict the germination potential and the genetic purity of coffee beans, from the comparison between the conventional tests. Thus, it is possible to obtain a methodology that is viable in economic, practical and technical terms, to predict the germination potential and the origin of the coffee seeds, but is not effective to predict the genetic purity of coffee seeds.