Contribution à l’évaluation de l’effet d’incorporation de la farine cuite de Quinoa (Chenopodium quinoa Willd) sur la qualité d’un yaourt brassé au cours de la conservation au froid.

Abstract

This study consists in exploiting quinoa flour in order to strengthen a stirred-type yogurt and create a new dairy product. Indeed, quinoa is newly introduced in Algeria, and recognized by its great capacity to adapt to very harsh pedoclimatic conditions, as well as by its richness in amino acids, trace elements and bioactive compounds, moreover it is a pseudo- gluten-free cereal. This work made it possible to study the evolution of some physico-chemical, microbiological and sensory parameters of stirred yoghurt added with cooked quinoa flour at different rates (0, 3, 6 and 9%) during the post-acidification. The evolution of the physicochemical parameters during the post acidification period revealed a gradual increase in acidity which is proportional to the rate of incorporation of the cooked quinoa flour. The results obtained remain within the compliance interval of the regulatory specifications apart from the stirred yoghurt with 9% quinoa flour added which exceeded this interval at the end of the storage period. On the other hand, a decrease in pH depending on the rate of incorporation of quinoa into the stirred yogurt was observed. In addition, the viscosity of yogurts was found to be all the more increased and therefore improved as the level of addition of quinoa flour is increased in yogurts. The microbiological analyzes showed, throughout the storage period, clear reductions in the number of Streptococcus thermophilus as a function of the increase in the rate of addition of quinoa flour to the product. On the other hand, compared to the control, the highest load of Lactobacillus bulgaricus was revealed in the yoghurt with 3% cooked quinoa flour (p<0.01); 19,105 vs. 29,105 CFU/ml. The organoleptic results revealed that the stirred yogurt with 6% quinoa added was the best appreciated by the tasting panel compared to the other products in terms of acidity, smell, taste and color and apparently it seems possible to incorporate plant flour at a rate of up to 6% without altering the organoleptic and physico-chemical quality of the yoghurt.