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

Mljekarstvo

Yıldız-Akgül, Filiz¹  Yetişemiyen, Atila²  Şenel, Ebru³ 

[1] Adnan Menderes University, Agriculture Faculty, Department of Dairy Technology, Aydın 09100, Turkey;Ankara University, Agriculture Faculty, Department of Dairy Technology, Ankara 06110, Turkey;Ömer Halisdemir University, Engineering Faculty, Department of Food Engineering, Niğde 51240, Turkey

关键词: kefir;    secondary fermentation;    microbiology;    physicochemical properties;    volatile aroma compounds;    sensory quality;   

DOI  :  10.15567/mljekarstvo.2018.0305

学科分类：工程和技术（综合）

来源: Hrvatska Mljekarska Udruga

【 摘 要 】

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.

【 授权许可】

CC BY