Effects of drying aids on quality of vacuum freeze-drying Rhodomyrtus tomemtosa powder

ObjectiveEffects of four drying aids on vacuum freeze-drying Rhodomyrtus tomemtosa powder were stu-died to provide reference for R. tomemtosa powder processing. MethodEffects of additions of maltodextrin, sodium carboxymethyl cellulose(CMC-Na), β-cyclodextrin and soy protein isolate on nthocyanin content, moisture content, in-stant time and sensory evaluation score were analyzed by single factor experiment. On this basis, comprehensive evaluation score was used as index. The optimal drying recipe was determined by orthogonal experiment. ResultAddition of mal-todextrin or β-cyclodextrin alone significantly decreased moisture content in R. tomemtosa powder (P<0.05 ,the same below ) ; CMC-Na significantly increased nthocyanin content; and soy protein isolate shortened instant time. The optimal drying aids recipe was as follows:mass ratio of maltodextrin to solid mater in R. tomemtosa juice 1:1, CMC-Na addition 1.2%, β-cyclodextrin addition 2.5%, and soy protein isolate addition 1.5%. Under these conditions, anthocyanins content in R. tomemtosa powder was 450.1 mg/L , moisture content 6.22%, instant time 23.0 s, sensory evaluation score 85.8 and comprehensive evaluation score 90.8. The powder was in good quality with red color, delicate texture and special flavor of R. tomemtosa. ConclusionJuice with mass ratio of maltodextrin to solid mater in R. tomemtosa juice being 1:1 is used as base, adding 1.2% CMC-Na, 2.5% β-cyclodextrin, and 1.5% soy protein isolate. The quality of R. tomemtosa powder by vacuum freeze-drying method is qualified. Most nutrient components are retained. In actual production, this recipe can be applied to process R. tomemtosa powder.