Effect of chufa flour addition on characteristics of yoghurt quality

Introduction.The purpose of the research is to determine the effect of the addition of chufa flour on the characteristics of yoghurt quality. Materials and methods.The yoghurt has been prepared by respecting the classic technological process, with the difference that chufa (Cyperus esculentus) flour has been added in different proportions (sample ICO3-0.3%,ICO5-0.5%,ICO7-0.7%).The yoghurt samples have been kept at a temperature of 2-4 °C for 15 days.Diacetyl has been determined by gas chromatography method, titratable acidity of yoghurt samplesby titration with 0.1N NaOH and syneresis using the methodology of Barkallah.Results and discussion.After the first day of storage, the diacetyl content is low in all the analyzed samples, but the ICO5 sample showed a higher diacetyl content of 6.5 µg/g.After 15 days of storage, the diacetyl content increased in all samples analyzed, so so diacetyl content of control sample is 6.4 µg/g, ICO3 -15 µg/g, ICO5 -16.2 µg/g and ICO7 18.8 mg/g.The high content of diacetyl is found in ICO7, which means that the addition of chufa flour has a positive effect for lactic acid bacteria used in the fermentation process.The acidity increases in all yoghurt samples analyzed from day 1 to day 15.The control sample shows lower acidity values between 80 and 108 °T, compared to the other samples, but the sample with a chufa flour in the proportion of 0.7% has acidity values between 87 and 125 °T, which indicates that the addition influences this characteristic analyzed.The highest removal of the serum was observed for control sampkle in 1 and 15 days, compared to the samples ICO3, ICO5 and ICO7.The ICO7 sample shows a lower syneresis, respectively on the first day of 9%, and the on 15th day of 32%.Conclusions.The addition of chufa flour improves the quality of yoghurt, which is of particular importance to the consumer in choosing these dairy products.