STUDY OF THE ENZYMATIC MACERATION KINETICS OF POTATOES IN A ROTATING PERFORATED DRUM REACTOR

A reactor system was developed to investigate the enzymatic maceration kinetics of potatoes. The reactor consisted of a rotating perforated drum contained in a cubical box. During the maceration process the tis sue liquefied, thereby increasing the dry weight of the fluid. From th e time dependent increase of the measured dry weight, the maceration r ate constant k (m.s-1) was determined. The effects of particle size, b lanching time, enzyme concentration, shear force as well as potato var iety on the rate constant k were investigated. The rate constant incre ased with particle size and enzyme concentration. The rate constant fo r unblanched potatoes was lower than for potatoes blanched during 5.0, 7.5, 10.0 and 12.5 minutes, but higher than for potatoes blanched dur ing 2.5 minutes. Potato varieties differing in textural properties sho wed different behavior in maceration experiments. The measured rate co nstant for the varieties studied ranged from 3.010(-7) up to 4.2*10(- 7) m.s-1. The high enzyme costs, 13% of the raw material costs, calcul ated on basis of the experimental results, showed that these costs wil l be prohibitive for large scale application of this technique.