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DEVELOPMENT OF A LABORATORY SCALE COMPUTERIZED TEST UNIT FOR THE SIMULATION OF DEEP BED FERMENTATION AND DRYING OF ROOIBOS TEA
Author(s) -
JOUBERT ELIZABETH,
STEENKAMP ZALDEUS,
MÜLLER RIKUS
Publication year - 1998
Publication title -
journal of food process engineering
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.507
H-Index - 45
eISSN - 1745-4530
pISSN - 0145-8876
DOI - 10.1111/j.1745-4530.1998.tb00462.x
Subject(s) - air velocity , inlet , fermentation , humidity , relative humidity , dry bulb temperature , spark plug , environmental science , air temperature , simulation , pulp and paper industry , chemistry , engineering , meteorology , mechanical engineering , food science , mechanics , geology , atmospheric sciences , physics
A test unit for the small‐scale fermentation and drying of rooibos tea was developed to simulate deep bed fermentation and drying of the tea in practice. The data acquisition and control system consisted of an AT type personal computer interfaced with the test unit by a plug‐in type AD/DA board. Set points such as temperature, relative humidity and velocity of the inlet air could be specified for eight sequential, variable time intervals. Good control of dry bulb temperature and velocity of the inlet air was obtained, taking into account the restrictions placed on the system by the hardware. The maximum air velocity that can be used with a bed depth of 50 mm, without formation of voids, was determined as 1.8 m/s. Precautions should be taken to ensure uniform air distribution and bed depth. Good quality tea was obtained after fermentation and drying in the test unit.