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Rapid moisture and fat determination by pulsed NMR for monitoring drying and coating processes of extrudates
Author(s) -
DAVENEL ARMEL,
MARCHAL PHILIPPE
Publication year - 1995
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.1365-2621.1995.tb01412.x
Subject(s) - extrusion , water content , coating , moisture , materials science , analytical chemistry (journal) , relaxation (psychology) , t2 relaxation , chemistry , chromatography , composite material , psychology , social psychology , geotechnical engineering , engineering , medicine , magnetic resonance imaging , radiology
Summary After extrusion cooking, extrudates must be dried and are often coated by spraying with fatty materials before cooling and packaging. As a means to control the drying and coating processes of pet foods, a rapid NMR method was developed to determine water and fat contents over a large temperature range without weighing, heating or measuring the temperature of the samples. Weighing was avoided by normalizing all NMR intensities by the solid echo maximum of each sample. Formulae using estimates of the transverse relaxation time and the concentration of liquid fat protons were used to determine total fat and moisture contents without measuring the temperature of the samples. Fat content estimation had a standard deviation better than 0.2% over a large solid fat index range above 20°C. Water content was determined with a standard deviation of about 0.2% at all temperatures studied.