Effect of using kefir in the formulation of traditional Tarhana

Abstract Tarhana is known as a fermented cereal product made traditionally from wheat flour and yoghurt. As a novelty, kefir was used as substitute for yoghurt in tarhana production partially and completely to investigate the effects on fermentation activity, nutritional, sensory and rheological properties of tarhana. Addition of kefir increased the fermentation activity as raise in acidity values was observed compared to tarhana samples prepared with yoghurt. Regarding dry tarhana samples, the highest acidity degree, protein, ash and phenolic contents were detected in samples prepared with 100% kefir. Counts of LAB groups (M17 and MRS agar) of tarhana enriched with 100% kefir was higher than that of other tarhana samples during the fermentation period. Moreover, kefir affected the scores of sensory properties of tarhana soups. Tarhana soups prepared with kefir gave the highest scores for mouth feel, odour and consistency attributes. Tarhana soup prepared with 50% yoghurt and kefir showed the lowest viscosity probably due to synergistic effect on starch hydrolysis by bacterial population from both ingredients. These results suggest that replacement of yogurt with kefir in the formulation of Tarhana may enhance some properties of the soup.

【摘要】塔尔哈纳（Tarhana）是一类以小麦粉与酸奶为传统原料制备的发酵谷物制品。本研究创新性地采用开菲尔（kefir）部分或完全替代酸奶应用于塔尔哈纳的生产，旨在探究其对塔尔哈纳发酵活性、营养特性、感官品质及流变学性质的影响。相较于仅以酸奶制备的塔尔哈纳样品，添加开菲尔可提升发酵活性，表现为酸度值显著升高。针对干燥塔尔哈纳样品，100%开菲尔制备的样品其酸度、蛋白质、灰分及酚类物质含量均为最高。发酵周期内，以M17和MRS琼脂培养基计数的乳酸菌群（LAB）菌落数，在100%添加开菲尔的塔尔哈纳样品中高于其余所有样品。此外，开菲尔对塔尔哈纳汤的感官评分存在显著影响：以纯开菲尔制备的塔尔哈纳汤在口感、气味与稠度属性上得分最高。采用50%酸奶与50%开菲尔混合制备的塔尔哈纳汤粘度最低，这可能源于两种原料所含菌群对淀粉水解的协同作用。上述结果表明，在塔尔哈纳的配方中以开菲尔替代酸奶，可提升该汤制品的部分品质特性。