Transformações físico-químicas e sensoriais durante o envelhecimento de café torrado em grão

• Author(s): Marques, João Manuel Simões da Silva
• Date: 2011
• Persistent ID: http://hdl.handle.net/10400.5/4034
• Origin: Repositório da UTL
• Subject(s): roasted coffee; shelf-life; sensory analysis; physical-chemical analysis; aging
• Document Type: Master thesis
• Language: Portuguese
• Advisor(s): Almeida, Maria Helena Guimarães; Brazão, Ana Cristina
• Contributor(s): Repositório da Universidade de Lisboa

Description

Mestrado em Engenharia Alimentar - Qualidade e Segurança Alimentar - Instituto Superior de Agronomia

The aging process of commercial roasted coffee, throughout its shelf-life, is little known. In this work we studied a commercial blend of roasted coffee beans during their shelf-life, in order to understand the changes that occur at the sensory and physico-chemical composition, and to identify possible indices of aging. Samples with 0, 6, 12, 18 and 24 months of storage were subjected to descriptive sensory analysis and physical-chemical (moisture content, aqueous extract, fat, fatty acids, color, titratable acidity, pH, peroxide, caffeine and trigonelline). It was concluded that aging was developed in two main phases. In the first (up to 12-18 months), the characteristic flavor, color, body and bitterness intensity decreased but acidity, peroxides, the metallic flavor, color, and trigonelline increased, mainly due to the hydrolysis reactions fat. In the second phase (18-24 months) continued to increase the humidity and the rancid flavor, the bitterness seems to have diminished. The fat changes have evolved in relation to the previous phase, being particularly evident the effects of oxidation reactions, which determined, sensory, the end of life of the blend studied.