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Continuous enzymatic cooking and liquefaction of starch using the technique of direct resistive heating
Author(s) -
Varella V. L.,
Concone B. R. V.,
Senise J. T.,
Doin P. A.
Publication year - 1984
Publication title -
biotechnology and bioengineering
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.136
H-Index - 189
eISSN - 1097-0290
pISSN - 0006-3592
DOI - 10.1002/bit.260260703
Subject(s) - starch , liquefaction , suspension (topology) , materials science , microwave , pulp and paper industry , process engineering , chemistry , chemical engineering , food science , organic chemistry , mathematics , engineering , telecommunications , homotopy , pure mathematics
Continuous cooker prototypes of very simple design, using electricity as a primary energy source, were developed for the process of cooking and liquefaction of starch suspensions. Previous work on equipment using microwave dielectric heating has already been reported. Results of energy consumption as low as 330 kcal/kg based on starch content were achieved. Considering these results and looking for new solutions or engineering concepts, the authors have been investigating the possibility of using electric energy at 60 Hz for direct resistive heating, in which the starch suspension is the proper “resistor.” The most important results of energetic yield obtained until now, working in a continuous process of cooking–liquefaction, are not larger than 235 kcal (272 Wh)/kg based on starch content. These results were obtained using a commercial grade α‐amylase from B. subtillis , working with temperatures ranging from 70 to 75°C, and with residence times in the reactor not greater than 1.5 min. The experiments of saccharification and fermentation accomplished as a test for the efficiency of this heating technique gave good results (as with a conventional technique) and thus enabled us to proceed with the studies.