PHYSICAL AND FUNCTIONAL PROPERTIES OF JERUSALEM ARTICHOKE FLOUR PRODUCED BY DIFFERENT DRYING METHODS

Abstract

Physical (pH, color & viscosity) and functional properties (water & oil absorption; foam capacity & foam stability; oil emulsion capacity & stability) of Jerusalem artichoke flour (JAF) produced by different drying methods (sun, oven & microwave) were studied. Measurements of pH values were (5.94), (6.14 to 6.33) and (6.26 to 6.37) with microwave, oven, and sun dried flour, respectively. The L* value (Lightness) were high for different flour comparable to control. The highest mean values of L* were detected in the samples dried by sun (66.66 to 71.57) followed by oven (64.50 to 71.32), and microwave (55.93). Flour prepared by oven drying at 60 oC/7 hr exhibit high viscosity (220 to 319 c.p.). Water and oil absorption capacity of different flour of JA varied considerably depending on the type of treatment and degree of temperature. All treated samples resulted in a significant (P< 0.05) increased in water & oil absorption comparing to control. The results of foam capacity & foam stability of the flour didn't show real foam. The emulsifying capacity of the examined treated flour is lower than that recorded with control at the same pH values. The highest mean value of emulsifying capacity was detected with microwave dried samples at pH7.0 (178.4 ml oil/ g sample), however, the lowest was detected in flour dried by sun at 40 oC/72 hr and pH6.0 (110 ml oil/ g sample).