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Purple basil was used as powder or water extract forms in the manufacture of yogurt for possible contribution on its taste and flavour of yogurt. The volatiles were extracted by solid-phase micro-extraction and then determined by gas chromatography-mass spectrometry (GC-MS) system. Effects of the addition of purple basil as powder or water extract form on the volatile composition and sensory characteristics during 3 weeks of storage at 4°C were evaluated. Forty-nine compounds were identified in the volatile composition of yogurt samples, including 12 ketones and aldehydes, 9 esters, 7 acids, 8 alcohols, 9 terpenes, and 4 miscellaneous compounds. Acetoin, ethyl acetate, hexanoic acid, acetic acid, 1-hexenol, 3-hexen-1-ol, 2ethylhexenol, dL-limonene, and linalool were most frequently identified volatiles in the yogurt samples. The level of linalool, which was main volatile in basil, was higher in powder basil flavoured yogurt samples than those in extracted basil flavoured yogurt samples. Principal component analysis of the GC-MS data showed that use of basil as powder or water extract form significantly changed the volatile profile of yogurt during storage. Also, sensory scores for basil-free yogurt were higher than yogurt samples manufactured by incorporating basil. In conclusion, use of basil enhanced the volatile composition of yogurt, and basil-flavoured yogurt may be offered for consumers as an alternative type of flavoured yogurt.

Four different types of yoghurt were manufactured using purple basil which was added to milk as water extract or powder forms at levels of 1.0 % and 0.4 % (w/w). Physicochemical and rheological properties, antioxidant capacity, color and total phenolic contents of yoghurt samples were measured during 21 days of storage. None of changes were observed for titratable acidity, pH and hardness parameters of yoghurt samples; however, some changes were observed during storage. The contents for total phenolic compounds and antioxidant activity [2,2'-Azino-bis(3-ethylbenzothiazoline-6-sulfonic acid diammonium salt (ABTS+*) and 2,2-Diphenyl-1-picrylhydrazyl (DPPH*) values] were dramatically higher in powder-added yoghurt samples than those of its water extract counterparts, while the lowest total phenolics and ABTS+* were observed in control sample during storage. The values for storage and loss modulus were higher in water extract-added samples than powder-added counterparts. In conclusion, no significant effect of the addition of powder or water extract of basil was observed on gross chemical characteristics of yoghurt, while use of basil powder positively contributed to antioxidant activity and changed the rheological behavior of yoghurt gel.

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