The Improvement Of Brown Rice Quality By Low-temperature Plasma Treatment Based On Dielectric Barrier Discharge

Brown rice is a kind of rice that remains the bran layer after husking,it contains a variety of nutrients that are beneficial to human health over time.However,due to the poor permeability of the bran layer and the presence of cellulose,brown rice is difficult to cook and taste bad.To address these issues while preserving the bran layer,the surface treatment of brown rice with dielectric barrier discharge(DBD)plasma was used in the study.The effects of DBD plasma discharge voltage,pulse frequency and duty cycle on the treatment effect were investigated,the properties of cellulose in brown rice after treatment were studied.The main studies are as follows:(1)DBD plasma treatment container design.The overall structure of the container was designed and suitable materials were selected for each component based on the need for uniform treatment of brown rice,the electrode part is made of metal and the rest is made of nylon to ensure the strength and safety of the container.The key components of the container were selected by using vibration theory,A spring with a total elasticity coefficient of 46.88 mm/g and a motor with a total excitation force of6.62 N were selected.Ultimately,the container works in a super-vibrating state so that the brown rice can be uniformly treated in a continuous tumbling state in the treatment container.This container enables the uniform treatment of brown rice in the DBD plasma and can be used as a reference for the development of future large-scale processing equipment.(2)Effect of DBD plasma discharge parameters on the quality of brown rice.The parameter adjustment range of the DBD plasma power supply was determined with the objective of not changing the consumption properties of brown rice during the treatment and making the BDD plasma power supply work efficiently.Compared to untreated brown rice,the cooking quality(cooking time,water absorption),texture,and digestibility of brown rice were significantly improved.And all of them improved more with increasing duty cycle,increasing output voltage and decreasing pulse frequency.The cooking time of brown rice was reduced from 37.3 min to 28.8 min at most,the water absorption at 1 h increased from 11.72% to 14.41% at most,and there was a decrease in hardness and chewiness of about 34.8% and 32.5% at most,respectively.The increase in digestibility at 30 min was up to 39.8%.The yellow color of the brown rice deepened but no significant change could be distinguished by the naked eye.(3)Changes in cellulose properties in brown rice.The cellulose in brown rice mainly occurred physical changes.the Fourier infrared spectroscopy and X-ray diffraction results of cellulose indicated that the functional groups,crystal type and cell size of cellulose were almost identical before and after treatment.The crystallinity of cellulose decreased from 64.10% to 45.69%,the solubility increased from 8% to85.84%,the polymerization decreased from 3999.52 to 987.86,and the reducing sugar content increased from 0.29 mg/g to 3.19 mg/g.The etching of the cellulose surface could be clearly observed under Scanning Electron Microscope.