关键词: 调制乳, 复原奶, 工业化, 响应面, 稳定剂, 总沉淀指数（TSI）

Abstract: [Objective] The formulation of reconstituted milk is influenced by factors such as the origin of powdered milk,nutritional indicators,usage proportions,emulsifiers,and process parameters. However,during the sterilization process,excessive scaling in the insulation pipes and the occurrence of excessive sedimentation in the final product can lead to instability. [Method]In this study,a single-factor experiment was conducted to explore the influence of emulsifiers,buffering salts,powdered milk brands,reconstitution temperature,and duration on the stability and flavor of the product. Based on the results of the single-factor experiment,a response surface methodology using Box-Behnken design was employed to optimize the application proportion of emulsifiers,reconstitution ratio of powdered milk,and reconstitution temperature. [Result]The results of the single-factor experiment indicated that a certain brand of full-fat powdered milk from New Zealand performed better than those from Australia and the United States.A reconstitution ratio of 1︰7.5 with a reconstitution time of 30 minutes and a reconstitution temperature of 45 ℃ yielded superior results compared to other conditions. The combination of single and double glycerol esters,sodium tripolyphosphate,and FH emulsifiers showed better stability than other combinations.The response surface model established for the optimal solution suggested an emulsifier addition proportion of 0.26%,a reconstitution ratio of 1︰7.2 for the full-fat powdered milk from New Zealand,a reconstitution temperature of 45 ℃,and a reconstitution time of 30 minutes.The predicted sensory score was 9.273,with an average TSI（Total Sediment Index） of 0.171 for the top and bottom,and a centrifugal sedimentation rate of 0.31%.The p-values for all three models were <0.001,and the corresponding R² values ranged from 0.948 to 0.981,indicating a high degree of agreement.These optimal conditions were verified through pilot-scale experiments,yielding a comprehensive sensory score of 9.14,an average TSI of 0.182 after 24 hours,and a centrifugal sedimentation rate of 0.35% under the conditions of 3 000 r/min for 30 minutes.These results were close to the predicted values,demonstrating the effectiveness of the models.The viscosity rate was measured at 0.25%,the homogenization index was 5.70%,and the final product had a pH value of 6.42,indicating good stability.The verification results under industrial production conditions showed that in the process of continuous production of 90 tons,the pressure increase of the formula and process parameters corresponding to the middle section after trial production was significantly improved compared with the production scheme（original formula） of compound emulsion stabilizer（mono- and diglycerol fatty acid esters + FH）,and the sensory flavor results were consistent with those in the laboratory. [Conclusion] The response surface methodology effectively models the additive ratios of the stabilizers in the modulated milk, as well as the relationships among reconstitution ratio, temperature, and duration. This provides a foundational basis for addressing special production conditions, such as excessive thermal cycling during industrial milk powder processing. It aids in the rapid and accurate response to corresponding operational strategies.

Key words: formulated milk, reconstituted milk, industrialization, response surface, stabilizer, Total Sediment Index（TSI）