Use of response surface methodology to optimize yoghurt and sugar of drinking yoghurt containing green tea

Abstract

Yoghurt and sugar were main ingredients of ready-to-drink yoghurt mixed with green tea. The responsesurface methodology was employed to determine the optimized quantity of these constituents. The addition ofyoghurt and sugar influenced product quality in all aspects of physical, chemical, microbiological, and sensory.The appropriate quantity of yoghurt and sugar in ready-to-drink yoghurt mixed with green tea was computed byDesign-Expert program and resulted in 20% for both components. The subsequent experiment with this formulayielded a good quality yoghurt with the following properties; L value (46.83), aw (0.88), total soluble solid (19.1oBrix),pH (4.51), protein content (0.44%), reducing sugar content (0.43%), sucrose content (16.27%), total sugar content(16.69%), lactic acid content (1549 ppm), moisture content (80.43%), and ash content (0.08%).