Low-fat and sugar-free yoghurt

6-kestose, nystose, cassia gum and calcium stearyl lactylate are added in a formula, so that bad phenomena of low viscosity, poor mouth feel, whey separation and the like due to no white granulated sugar and relatively low fat content of low-fat and sugar-free yoghurt can be improved. After preprocessed lycopene and beta-carotene are reasonably matched, the improvement effect of 6-kestose, nystose, cassia gum and calcium stearyl lactylate on the bad phenomena of low viscosity, poor mouth feel, whey separation and the like can be promoted, so that the low-fat and sugar-free yoghurt is better in viscosity and mouth feel but a problem that the number of viable bacteria in the low-fat and sugar-free yoghurt is greatly reduced occurs at the same time. Explorations discover that in combination with a specific process, the problem that the number of viable bacteria is greatly reduced can be solved and the promotion effect of preprocessed lycopene and beta-carotene on the improvement effect of 6-kestose, nystose, cassia gum and calcium stearyl lactylate on viscosity and mouth feel is ensured.