Yoghurt production by Iranian native starter cultures

Abstract

Purpose -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. Design/methodology/approach -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. Findings -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. Originality/value -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.

Effect of the addition of roselle (Hibiscus sabdariffa L.) extracts on the rheological, textural, and antioxidant activity of fermented milks

“…The TPA parameters represented the textural characteristics of fermented milk well, including firmness, consistency, cohesiveness, and index of viscosity . Different TPA parameters of fermented milk samples were measured, as presented in Table .…”

Identification, typing and functional characterization of dominant lactic acid bacteria strains from Iranian traditional yoghurt

“…The remaining strains coagulated milk, producing a coagulum of good appearance and phenotypic tests, which have repeatedly proved to be unreliable for the identification of LAB. In addition, isolated strains have rarely been subjected to genotypic fingerprinting [53] or technological analyses [42]. Our knowledge of the LAB microbiota of Iranian traditional yoghurts therefore remains wanting.…”

“…This ensures the selection of thermophilic microorganisms [55]. Many rural areas of Iran have a long tradition in the manufacture of yoghurt and other milk products, and microbial analyses of some of them have already been undertaken [1,21,42]. However, the strains isolated have mostly been identified via Abstract Interest in the microbiota of traditional fermented dairy products, such as yoghurt, continues due to the need for new lactic acid bacteria (LAB) strains that can complement or replace currently-in-use starters.…”

Changes in physico-chemical characteristics and volatile flavour components of different yoghurt products made from soy, peanuts and cow milk

“…Lactic acid, acetaldehyde, diacetyl, acetoin, acetone, and 2-butanone have been noted to contribute to the typical flavour of yoghurt [13]. The major volatile compounds that are responsible for imparting desirable flavour to yoghurt are the carbonyl compounds: acetaldehyde, diacetyl, acetone, acetoin, and 2-butanone [13,15,16]. The analysis of flavour components of different types of vegetable milk yoghurts is critical in determining consumer acceptability of a particular yoghurt from a legume milk source.…”