Background: Functional foods are currently in great demand by consumers. This study aims to assess the impact of hydroethanol extract of C. longa (turmeric) as a coloring agent and functional ingredient, by evaluating its effects on physicochemical and microbiological properties, as well as on the organoleptic quality of natural yoghurt-type fermented milk. Methods: Cucurma extracts, obtained from C. longa rhizomes, were added at 1 mg, 2 mg, 3 mg, 4 mg and 5 mg per 100 mL of milk. A control yoghurt was also prepared without the addition of C. longa extract. Physico-chemical analysis was carried out to measure pH, acidity and viscosity. Microbiological analysis was carried out to assess the viability of Streptococcus thermophilus and Lactobacillus delbrueckii ssp bulgaricus. Finally, a sensory evaluation was carried out with 20 panellists. Result: Physico-chemical analyses revealed that the incorporation of turmeric extract led, on the one hand, to a significant lowering of pH with an increase in acidity and an improvement in yoghurt viscosity. On the other hand, yoghurts enriched with turmeric extract showed no significant difference in sensory appearance, apart from an improved perception of color and flavor. Overall, the incorporation of extracts at doses of 1 mg to 3 mg had a favorable impact on physicochemical parameters, with sensory acceptability, a reduction in the viability of specific lactic acid bacteria to the acceptability threshold prescribed by the International Dairy Federation, controlled post-acidification and better bioprotection of yoghurt against spoilage micro-organisms at the expiration date.
Benzineb et al. (Tue,) studied this question.