Microbiological, physicochemical, and sensory characteristics of kefir produced by secondary fermentation

Abstract

In this study, the microbiological, physicochemical, and sensory properties and volatile aromatic compounds of kefir produced by secondary fermentation were investigated. Cow milk samples containing 1.5 % fat were fermented with kefir grains until the pH reached certain levels (pH 5.0-5.5), and then each of them was inoculated with a different starter culture (thermophilic, probiotic, mesophilic aromatic, and yeast) for secondary fermentation. In kefir samples produced traditionally or by secondary fermentation, the pH values, carbon dioxide levels, and tyrosine and lactic acid contents increased during storage. However, the counts of lactococcus, lactobacillus, leuconostoc, and yeasts decreased. Acetaldehyde and ethanol increased during storage, but diacetyl decreased in kefir samples produced traditionally or by secondary fermentation. The butanone contents changed very little but they showed an upward trend within the storage period. Kefir samples produced by secondary fermentation found greater acceptance during sensory testing than samples produced by the traditional method. Kefir inoculated with mesophilic aromatic and yeast cultures were the most preferred by panelists.

Exploitation of Yeasts with Probiotic Traits for Kefir Production: Effectiveness of the Microbial Consortium

“…Ten trained tasters expressed their score using a 10-point hedonic scale (10 = like extremely; 0 = dislike extremely) regarding overall acceptability texture, smell, viscosity, acidity, bitterness, and sweetness for each sample. The sensory analysis was conducted similarly to that reported by Yıldız-Akgül et al [24]. Specifically, the tasting was conducted blindly using a panel of 12 tasters, 6 males and 6 females aged between 24 and 60, habitual consumers of fermented milk.…”

Consortium of selected yeasts to produce healthy soy fermented beverage: Evaluation of microbial evolution, analytical, sensorial, and functional features

“…They expressed an opinion regarding colour, texture, viscosity, acidity, bitterness, sweetness and overall appreciable sweetness of samples using a hedonic scale from 1 (dislike extremely) to 10 (like extremely) ( Supplementary Fig. S1 ) [ 15 ]. The analyses were carried out at the end of the shelf life of the products.…”

Effect of Cellulose–Chitosan Hybrid-Based Encapsulation on the Viability and Stability of Probiotics under Simulated Gastric Transit and in Kefir

“…was used. As previously reported by Yıldız-Akgül et al [ 18 ], the size and diameter of the prepared beads were evaluated.…”

“…For the selective enumeration of L. plantarum , the method of Yıldız-Akgül et al [ 18 ] was followed with some modifications. Serial dilutions were prepared for the inoculation of Kefir samples in order to determine probiotic enumeration.…”