Yoghurt consists of approximately 60 per cent of per capita dairy consumption of Iranian people. Iranian dairy factories use commercial starters which are expensive in yoghurt production. Moreover, yoghurt produced by these starters does not completely meet the taste of Iranian consumers. The aims of this study are to produce well qualified yoghurt from isolated native starters and to evaluate microbial, chemical and organoleptic characteristics of products.
The microflora of Iranian native yoghurts were isolated, purified and identified. The isolated strains were used as starter for the production of yoghurts. Sensory evaluation and measurement of pH, acidity and acetaldehyde content of the samples were carried out. Acidity, pH, acetaldehyde content, and microbial population of the best samples were measured during 21 days of cold storage. SPSS software was used for statistical analysis.
During the above mentioned storage period, acidity and acetaldehyde content increased significantly (p < 0.05). Significant decreases (p < 0.05) were observed in pH and microbial population. No significant difference in organoleptic characteristics (taste, smell and texture) were found after 21 days of cold storage.
Yoghurt production by native starter cultures instead of commercial ones is beneficial in respect of both economic and organoleptic aspects. The results indicate that the use of isolated native yoghurt starters in manufacturing yoghurt can be satisfactory and can also be extended to the production of yoghurt on an industrial scale.
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