Abstract: [Objective ]To develop a healthy and delicious compound yoghurt with purple sweet potato,coconut milk and milk powder as main raw materials,and to determine its basic physicochemical and microbiological indexes. [Method] Sensory score and titrated acidity were used as evaluation criteria,and single factor test and orthogonal test design were adopted,the optimum technological parameters of adding ratio of purple sweet potato and coconut milk,adding amount of honey, fermentation time and fermentation temperature were screened out. [Result]Under the condition of adding 160 g of purple sweet potato and coconut milk,the optimum formula of compound yoghurt was: adding 3:1 of purple sweet potato and coconut milk,adding 60 g of honey,fermenting time 7 h, fermenting temperature 43 ℃. [ Conclusion ]All the basic physicochemical and microbiological indexes of the compound yoghurt produced by this formula were in accordance with the national standard. The comprehensive sensory score was 89.3 and acidity was 56.18 ^。T,rich in high-quality protein and dietary fiber,smooth taste,moderate sweet and sour,viscosity appropriate,purple sweet potato flavor rich,there is a light coconut,tonic spleen qi,beauty role.

Key words: purple sweet potato, coconut milk, complex yoghurt, acidity, optimal technology