Dados do Trabalho

Título

RAMAN SPECTROSCOPY AND MULTIVARIATE CONTROL CHART AND QUALITY OF COATED AND STORED GREEN COFFEE BEANS

Introdução

Raman spectroscopy was applied to identify chemical changes and develop control charts to investigate the stored green coffee beans with biopolymer coatings (chitosan and carnauba wax) and those without coatings.

Material e Métodos

The covered beans were packed in high-barrier and permeable packaging materials and stored for 12 months. Sensory analysis with expert tasters and statistical analysis was done to clearly identify the best way to treat the spectroscopic data and support the conclusions.

Resultados e Discussão

The sensory results indicate that the use of the coating technique was efficient in preserving the quality of the beverage during storage time, with 82 to 84 points. This technique was able to minimize the effect of chemical changes that occur in the grains. The coating effect was more pronounced in preserving grain´s characteristics in permeable packaging than in high barrier packaging due to the protection of the packaging itself. The Raman spectroscopy bands in the region between 1460 and 1600 cm-1 are due to kahweol, and the changes detected in the uncoated samples suggest that this compound participates in the quality loss effects. As for the coating, carnauba wax had a more intense preservation effect than chitosan.

Conclusão

Together with the sensory analysis, Raman spectroscopy proved to be a very efficient way to observe and monitor the changes in the main characteristics of the coffee during the storage period. The obtained results point out that coating treatment can maintain the quality of the beverage for a longer time. The Raman spectroscopy results indicate that the major changes occur in regions of vibrations of the kahweol molecule.