Effects of speed and time of wet milling on properties of dietary fiber powder from pomelo's albedo

Abstract

The aim of this research was to study effects of speed (16,820 18,220 and 20,220 rpm) and time (1, 3 and 5 min) of wet milling on physical and chemical properties of dietary fiber powder prepared from pomelo’s albedo. It was found that the milling speed had more effect on the powder properties than the milling time. Increasing of milling speed caused an increasing in L* value, oil holding capacity, water activity and insoluble dietary fiber content but reduced water dietary fiber powder including, L* value of 97.29, yield of 11.40 %, water activity of 0.207, moisture content of 7.84 % on the wet weigh basis, pH level of 5.10, water holding capacity of 14.50 g water/g dry matter, oil holding capacity of 2.38 g oil/g dry matter, insoluble dietary fiber, holding capacity and soluble dietary fiber content. The prolonged milling time caused an increasing in oil holding capacity, but decreased water holding capacity. Wet milling of pomelo’s albedo at high speed for 1 min resulted in acceptable physical and chemical properties of soluble dietary fiber and total dietary fiber content of 44.57, 35.45 and 80.02 % on the dry weigh basis, respectively. Thus, wet milling at 20,220 rpm for 1 min was an appropriate condition to be used with other steps in production of dietary fiber powder.