Effects of low temperature and washing on the vibration superfine grinding performance of wheat bran

To explore the effects of low temperature and washing on the superfine grinding performance of wheat bran, two types of wheat bran samples were prepared: unwashed wheat bran (UWB) and washed wheat bran (WWB). The vibration grinding experiments of UWB and WWB were carried out at different grinding temperatures by using the low-temperature vibration grinding experimental platform. The results showed that the powder quality of UWB was greatly affected by low temperature, and the effect of low temperature on the WWB was less obvious. The results also showed that the particle size distribution curve of the UWB micro powder changed from a double peak curve to a single peak curve as the grinding temperature decreased. The similarity of the particle size distribution curves of the two types of wheat bran micro powder decreased with the decrease in grinding temperature, and the maximum decrease was about 60%. Compared with the results obtained at ambient temperature, the maximum difference rates of the mass fractions of the two types of wheat bran superfine powder within the grinding temperature range were 29.91% and 50.16%, respectively. At the same grinding temperature, the difference in mass fraction between the two types of wheat bran superfine powder was about 50%. The sensitivity of the yield of UWB superfine powder to grinding temperature was greater than that of WWB. The difficulty of superfine grinding of WWB was greater than that of UWB. According to the laminate theory of composite materials, the essence of the changes in the particle size of UWB superfine powder was revealed, and the relationship between the mass fraction of residual endosperm superfine powder and the grinding temperature was obtained. The results can be applied to improve the yield and quality of the further processing of wheat bran.