Research On Edible Quality Characteristics And Improvement Of Brown Rice Based On Low Temperature Plasma

As an important whole grain,brown rice is rich in nutrients.Brown rice has a dense layer of seed coat on its surface,and it has problems of long cooking time,indigestion,and poor taste when eaten in a granular manner,making it difficult to become a mainstream food on consumers’dining tables.In order to preserve the nutritional content of brown rice to the maximum,shorten the cooking time of brown rice,and improve the sensory quality of brown rice,a quality evaluation system for brown rice was constructed in this study.The principal component analysis method was used to optimize the brown rice variety with the best comprehensive quality.The role of plasma technology in improving the quality of brown rice and the influence of different lithographic conditions on the cooking time and solids loss rate of brown rice;The nutritional quality,cooking quality,sensory quality and flavor of brown rice were analyzed by low-temperature plasma treatment.The main conclusions are as follows:（1）The nutritional quality,cooking characteristics,taste quality and flavor components of 7varieties of brown rice in different regions were measured,and the overall quality of brown rice varieties was evaluated by the principal component analysis method,and brown rice varieties with better quality were selected.The results showed that different varieties of brown rice had significant differences in quality such as cooking property,hardness,sensory quality,gelatinization temperature,and regeneration value（p<0.05）.Principal component analysis builds a comprehensive quality evaluation model.The cumulative variance contribution rate of the three principal components reaches86.73%.The cooking time,the loss rate of solids,hardness,gelatinization temperature,regenerative value,sensory and other cooking characteristics,texture paste characteristics and sensory qualities of brown rice directly reflect the comprehensive quality of brown rice.Among them,Heilongjiang long-grain fragrant brown rice has the highest comprehensive score,and is more suitable as a raw material for co-ripened brown rice.（2）The microstructure shows that pits and cracks appear on the surface of the brown rice cortex after low-temperature plasma pretreatment;the glow intensity and moisture content are inversely proportional to the brown rice cooking time after treatment,and are directly proportional to the etched area and solids loss rate of the brown rice surface;With increasing,the etched area on the surface of brown rice decreases first and then increases,and the cooking time of brown rice also decreases first and then increases,while the solids loss rate tends to increase first and then decrease.Under the conditions of a glow intensity of 1.8 A,a processing time of 2 minutes,and a moisture content of 9.33%,the shortest cooking time of brown rice is 25.31 minutes.At this time,the solids loss rate is 19.18 mg/g,which is 26.5 times shorter than that of the control brown rice.%,The solids loss rate has increased by 20%.（3）Low temperature plasma treatment can effectively improve the cooking and eating quality of brown rice.Compared with the brown rice of the control group,the heated water absorption,volume expansion rate and solids loss rate of brown rice after low temperature plasma treatment increased significantly;The amylose content of brown rice also increased significantly.The elasticity of brown rice increased by 7%,the viscosity increased by 4.3%,the sensory score increased by 7.55%,and the hardness and chewability decreased by 27.3%and 27.8%,respectively,which significantly improved the quality of brown rice.（4）The low-temperature plasma treatment mainly acts on the brown rice skin layer.The brown rice skin layer is damaged and deformed,and the surface has pits and cracks,exposing starch and protein particles,accelerating the opening of water into the channel,making it more prone to gelatinization,which can effectively shorten the cooking time.Improve the edible quality;the relative area of the peak value of the OH group at a wavelength of 1650 cm^-1 in the infrared spectrum increased,and the starch particles showed higher hydrophilicity.High-energy particles produced by low-temperature plasma continuously bombarded brown rice,depolymerizing starch particles,reducing crystallinity,and improving the ability of starch particles to bind water and gelatinization characteristics.（5）The match between brown rice（BR）and brown rice（LTP-BR）after low-temperature plasma treatment volatile substances is 83.25%;2,3-butanedione,acetone,eucalyptol monomer,eucalyptus dimer,n-hexanol monomer,n-hexanol dimer,diallyl disulfide,LTP-BR raw material after low temperature plasma treatment.The relative concentrations of ketones,terpinenes,limonene,and limonene increased,showing more floral and pine odors.The matching degree of brown rice（C-BR）and brown rice after low-temperature plasma treatment C-（LTP-BR）is 89.5%.The low-temperature plasma increases the relative concentrations of aldehydes and terpenes in the C-（LTP-BR）sample.The odor characteristics are grassy and fruity.Mainly,pine wood fragrance plays a certain role in supporting the overall flavor of brown rice;however,it has little effect on alcohols,ketones and other substances,which indicates that low temperature plasma enriches the flavor of brown rice without the generation of undesirable flavor substances.