Study Of Anti-caking Of Jujube Powder And The Development Of Related Product

Jujubes attract lots of consumers because of its high nutritional value.However,jujubes are easily mildewed after the dry during preservation,resulting in great losses to the industry and restricts the development of jujube.Jujube powder as a deep-processing production is important for the development of jujube industry,while jujube powder has high hygroscopicity impacting its quality and development.Therefore,in this study,the physical characteristics and hygroscopic properties of jujube powder prepared by different drying methods were investigated.The main research contents and results are as follows:(1)The effects of different anti-caking agent on the physical characteristics of jujube powder produced by different drying methods were studied.Jujube powder dried by air-hot showed bright color of reddish,good sensory quality,heterogeneous surface structure.Moreover,supplementation with 0.6% silica,0.3% tricalcium phosphate,or 0.4% avicel resulted in lower hygroscopicity and better flowability.In addition,jujube powder dried by spray showed higher soluble solids content and higher brightness of red and yellow,smaller maltodextrin content resulted in smooth particle surface and less shrinkage ratio of particles.Shrinkage of the particles,shrinkage degree,and particle bowl were increased with the increase of maltodextrin amount.In addition,the better ratio of soluble solids content of jujube juice to maltodextrin was 4: 5,resulted in lower hygroscopicity and better powder flowability.jujube powder dried by vacuum freeze powder and hot air showed insignificant brightness,the color of hot air dried jujube powder was redder and that of vacuum freeze-drying was yellower.Compared with hot air drying and spray drying,vacuum freeze-dried powder showed larger degree of shrinkage,shape rules,particles and larger pore surface area.Furthermore,maltodextrin addition resulted in regular hollow structure and longer time for dissolution.Hygroscopicity of jujube powder dried by spray was lower than that dried by vacuum freeze and hot air.Hygroscopicity of jujube powder dried by vacuum freeze was the highest.Addition of maltodextrin could reduce hygroscopicity of jujube powder significantly,and jujube powder supplemented with 30% maltodextrin exhibited the lowest hygroscopic rate and the best powder flowability.Therefore,spray-drying was the best technology for the production of jujube powder,with good flowability.(2)Hygroscopic properties of jujube powder were studied systematically.When the relative humidity was below 70%,change of mass of jujube powder with the relative humidity was not obvious.However,when the relative humidity was above 70%,the equilibrium moisture content of jujube powder was increased with the increase of relative humidity level.The moisture sorption isotherms of jujube powder was belonging to ? type,the equilibrium moisture content was increased with the increase of water activity,and the moisture adsorption isotherm showed a little hysteresis.GAB model fitting degree of jujube powder moisture adsorption isotherms of the four models(BET?GAB?Oswin?Smith)are the best(R2?0.99).With the water activity of 0.11,the glass transition temperature of jujube powder dried by hot air was 27.58°C,when the ratio of soluble solid content to maltodextrin was 4: 3,the glass transition temperature of jujube powder dried by spray was at least 25.22°C,while the glass transition temperature of other ratio was about 45°C.Glass transition temperature of jujube powder dried by vacuum freeze was increased with the increase of maltodextrin supplementation.Glass transition temperature of pure jujube powder was 3.64°C,and that of jujube powder added by 30% maltodextrin was 27.67°C.Therefore,spray-drying was better for the production of jujube powder with higher storage stability.(3)Technological parameters of jujube tea powder dried by spray were optimized.The addition of maltodextrin could reduce the viscosity of jujube juice and increase the flour yield of jujube powder.The best process parameters were as follows: the inlet temperature was 170°C,the ratio of soluble solid content to maltodextrin was 4: 7,under this condition,jujube tea flour yield was 54.08%,with moisture content of 4.31%.When the addition of non-dairy creamer was 40%,the score of final production was 90.