Effect Of Ultrafine Grinding On The Physicochemical Properties Of Apple Powder And Its Dietary Fiber

In this study,apple and dietary fiber as materials,compared with the crude powder,seven kinds of apple and apple dietary fiber powder with different particle size were obtained by different time(1 min,3 min,5 min,10 min,20 min,30 min)of superfine grinding.To explore the effects of different time of superfine grinding on physicochemical properties、microstructure and antioxidant activity of apple and apple dietary fiber,the physicochemical properties and antioxidant activity were determined,The particle size,structure and infrared spectrum of different apple dietary fiber powder were determined by laser particle size analyzer,scanning electron microscope and infrared spectroscopy.The application of dietary fiber in the bread were also studied.The dietary fiber powder of coarse grinding,submicron dietary fiber powder of 1min and 20 min were added to bread,the effects of dietary fiber with different particle sizes on bread quality and texture characteristics were studied,the sensory quality of bread was also evaluated.The main results are as follows:1 Effect of ultrafine grinding on the physicochemical properties of apple powderAfter ultrafine grinding,the particle size of powder decreases gradually and the particle size distribution becomes more uniform.Compared with the coarse grinding,after different time of ultrafine comminution,the swelling,water solubility,water holding capacity and the cation exchange capacity were increased,the volume density decreased(P<0.05);With the extension of ultrafine grinding time,the water holding capacity increased gradually(P<0.05),the bulk density and the swelling did not change significantly(P>0.05);the water solubility and the cation exchange capacity increased first and then did not change significantly(P>0.05).The agglomeration phenomenon occurred after ultrafine grinding of 10 min.With the extension of ultrafine grinding time,the agglomeration phenomenon was more serious,and the overall effect of 10 min powder was the best.2 Effect of superfine grinding on physicochemical properties and antioxidant activity of apple pomace dietary fiberThe grain size of dietary fiber was significantly decreased after ultrafine grinding.Compared with the coarse crushing,after different time of ultrafine comminution,the swelling,the water solubility and the cation exchange capacity increased(P<0.05),the hydroxyl radical scavenging ability increased(P<0.05),there was no significant change in water holding capacity and the bulk density(P>0.05).Between the superfine grinding processing,the bulk density,the water swelling,the solubility,water holding capacity and free radical scavenging ability showed no significant difference(P>0.05),the cation exchange capacity of powder changed significantly(P>0.05).The agglomeration phenomenon occurred after ultrafine grinding of 10 min.With the extension of ultrafine grinding time,the agglomeration phenomenon was more serious,the swelling ability and cation exchange capacity of the powder were decreased when the 30 min was crushed by ultrafine grinding,and the overall effect of 20 min powder was the best.3 The application of apple pomace dietary fiber in breadThe results show that the quality of bread structure has certain effect with different dietary fiber in bread,After adding dietary fiber,the specific volume of bread decreased,the water holding capacity increased,the hardness,chewiness,adhesiveness and elasticity decreased,compared with the control,the difference was significant(P<0.05).Compared with the bread with coarse dietary fiber powder,the addition of dietary fiber superfine powder had little effect on bread quality(P<0.05),and there was no significant difference between the two groups(P>0.05).Sensory evaluation results showed that dietary fiber was added to the bread,and the smaller particle size of the powder had less effect on the quality of bread.