Elektryczna metoda pomiaru wilgotności skrobi ziemniaczanej na wyjściu suszarki pneumatycznej

Przedstawiono zależność rezystancji elektrycznej skrobi ziemniaczanej od wilgotności. Wyniki opracowano w postaci wykresów prostej i krzywej regresji oraz równań korelacyjnych. Między rezystancją elektryczną, a wilgotnością istnieje bardzo silny związek korelacyjny. Wyznaczono odchylenia standardowe, efekt liniowy i nieliniowy modeli regresyjnych. Metoda rezystancyjna nie jest dotąd stosowana do pomiaru wilgotności skrobi ziemniaczanej w warunkach przemysłowych. Pomiar wilgotności jest natychmiastowy.

The paper presents a dependence of effective resistance of potato starch on moisture content at the outlet of a pneumatic drier. Results were presented in the form of plotted regression lines (Fig. 1) and regression curves (Fig. 2) an in the form of correlation equations (1) and (2). Very strong correlations (0.9846, 0.9997) were found between resistance and moisture content of potato starch. It results from available literature that there are no data on similar studies. To date only preliminary laboratory analyses have been conducted on the applicability of electric properties in measurements of moisture content in dried potatoes [4,5], dried carrots [6], dried vegetables [7] and other foodstuffs [8]. A novelty presented in this paper is the fact that the effective resistance method used in industrial practice facilitates rapid moisture content measurement in potato starch in the course of drying, which will contribute to an improvement of starch quality. The time of sample preparation for moisture content measurement is approx. 90 s and the measurement itself is instantaneous. Material for analyses comprised samples of potato starch with moisture content ranging from 15.2 to 24.7%. Starch drying was run in an experimental pneumatic drier. Effective resistance between sensor electrodes was a measure of moisture content in a given sample. Electric measurements were taken using a digital multimeter adapted to resistance measurements. Moisture content in starch samples was determined by gravimetry.