N. Voudouris et Ki. Hayakawa, PROBE LENGTH AND FILLING MATERIAL EFFECTS ON THERMAL-CONDUCTIVITY DETERMINED BY A MAXIMUM SLOPE DATA REDUCTION METHOD, Journal of food science, 60(3), 1995, pp. 456-460
The influence of probe length to diameter ratio (lambda) and filling m
aterial on the thermal conductivity (k) probe technique was studied us
ing glycerol with probes of four different lambda s (4.1, 7.5, 13.6, a
nd 54.3) filled with either high k paste or air by applying a maximum
slope data reduction method. Statistical analysis showed the highly si
gnificant influence of lambda and significant influence of the filling
material. Noncalibrated k values of the smallest lambda probes were 9
3% above the published value, whereas those of the largest lambda prob
es were virtually identical to the published value. Separate measureme
nts on chocolate pudding and starch gels showed that 7.5 lambda k were
virtually identical to the largest lambda probe k when the former pro
bes had been calibrated using glycerol. The use of short air-filled pr
obes is not recommended when the maximum slope method is applied.