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Thiamine destruction during extrusion cooking as an indicator of the intensity of thermal processing
Author(s) -
GUZMANTELLO R.,
CHEFTEL J. C.
Publication year - 1987
Publication title -
international journal of food science and technology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.831
H-Index - 96
eISSN - 1365-2621
pISSN - 0950-5423
DOI - 10.1111/j.1365-2621.1987.tb00520.x
Subject(s) - extrusion , isothermal process , arrhenius equation , plastics extrusion , thiamine , activation energy , die swell , chemistry , thermodynamics , plug flow , analytical chemistry (journal) , materials science , chromatography , composite material , organic chemistry , physics
Summary Assessment of the intensity of high temperature‐short time (HTST) extrusion cooking was studied by measuring the extent X A of thiamine destruction. Small quantities of thiamine hydrochloride (0.1–0.7 g per 100 g) were mixed with wheat flour (containing ∼ 14% water) prior to extrusion experiments. Results indicate that thiamine destruction follows an apparent first‐order reaction and that the rate constant K of destruction, calculated from near isothermal extrusion experiments at 133, 142 or 152°C (product temperature), follows an Arrhenius relationship with an activation energy of 49.9 kJ/mol. K values were calculated from experimental determination of X A and of the residence time distribution (RTD) in the effective heating zone of the extruder. The influence of product temperature (just before the die), water content during extrusion and speed of screw rotation on the overall K (for non‐isothermal extrusion experiments) was determined and analysed by multiple regression. Results show that thiamine destruction X A can be predicted by means of a linear mathematical model. Each experimental X A value can be used, in combination with Arrhenius equation constants and RTD, to express a given extrusion process in terms of equivalent isothermal temperature and equivalent plug flow residence time.