Preparation Of Whole-fat Instant Bitter Almond Powder By Spray Drying

With debitter almond as raw material,studied instant bitter almond pulp beverage,the spray drying technology of preparing instant whole-fat almond powder and the effects of spray drying process on almond powder's characteristics and quality.It's expected to provide a theoretical basis for the full utilization of bitter almond resources.The main results are as follows:1.Instant bitter almond pulp beverageThrough the study of the conditions of the amygdala colloid mill,the colloid mill refining process was determined: the ratio of bitter almond to water was 1:3.75,the soaking time was 8 hours,and the grinding time was 8 minutes.The final concentration of the final product was determined by the minimum ratio of material to water.Experiments showed that softening and prolonging the grinding time can improve the effect of colloid mill grinding.Based on the study of the technological conditions of bitter almond beverage,the best formula was determined as follows: 12.4% bitter almond,0.5% tripolyglycerol,18% sucrose,0.16% combined stabilizer of the ratio 1.5: 1 of xanthan gum to arabic gum,the homogenization pressure was 45 MPa.At the above conditions,the product had good stability and taste.2.The technology of spray drying to prepare instant whole-fat almond powderBy spray drying experiments,the formula of the slurry was determined when the proportion of 8.2% bitter almond,0.12% sodium tripolyphosphate,0.5% glycerol tripolyglycero,0.09% xanthan gum,0.06% arabic gum,0.03% sucrose trichloride and 10.0% sucrose were prepared.The addition amount of dextrin was 10% and the amount of microcrystalline cellulose was 0.12%.When the homogenization pressure controlled at 45 MPa,spray drying was well performed.The optimum spray drying process was obtained by single factor and orthogonal experiment: feed temperature 30 ?,feed concentration 28 ?,inlet air temperature 140 ?,inlet velocity 15,feed speed 6,spray pressure 0.16 MPa.3.Effects of spray drying process on characteristics of almond powderThe results showed that the inlet air temperature,inlet air velocity,feed temperature,feed concentration,feed speed and spray pressure,have a significant effect on the average particle size,roundness and particle size distribution of the spray dried whole-fat bitter almond powder.The influence law between them was analyzed,which provided the basis for spray drying process.Through the mechanism analysis,it was revealed that the average particle size,roundness and particle size distribution of the powder were the direct causes affecting the accumulation density,the slip angle,the angle of repose and the moisture absorption of the whole-fat bitter almond powder.Through expounding the change law between the key control factors and the characteristic index of powder,the better suggestions were provided for the control of spray drying process.4.Effects of spray drying process on the quality of almond powderThe effects of spray drying technology on fat content,acid value,peroxide value and hydroxyl radical scavenging ability in powder were studied in this paper but the degree of change was not obvious.It may be related to the contact of the material with warm oxygenated air and dextrin embedded almond granules during the spray drying process.The content of protein in spray drying process is stable,but the related research will lead to the decrease of solubility and the decrease of flushing ability.The change of water content and water activity was the same with protein,and the change of water activity is between 0.2-0.4,which provided a better basis for the application of spray drying in the process of almond powder.