>Between Canada, US and Britain, there must be at least 10 different "acceptable" ways of spelling yogourt (acceptable canadian version) . I would not be surprised of the spelling used in the paper was also an acceptable version.
Yogurt is a turkish origined word so it must be write as yogurt. In turkish it writes as "yoğurt", but in english there isn't "ğ" capital, so in english it writes as "yogurt"
"Ayran" is a turkish origined word too.
http://en.wikipedia.org/wiki/YogurtEtymology of 'yoghurt'
The word derives from the Turkish yoğurt (pronounced [jɔˈurt]) deriving from the adjective 'yoğun', which means "dense" and "thick", or from the verb yoğurmak, which means "to knead" and possibly meant "to make dense" originally -- how yoghurt is made. The letter ğ is silent between back vowels in Modern Turkish, but was formerly pronounced as a voiced velar fricative [ɣ] and still retains this pronunciation in some eastern dialects. English pronunciation varies according to the local accent but common pronunciations include /ˈjɒgət/ and /ˈjoʊgɚt/.