Prabha, R.Krishna, R.Manjunatha, H.Venkateshaiah, B.V.Narasimha MurathyShivalkar Yadav, K.2016-11-162016-11-162011-06-15http://krishikosh.egranth.ac.in/handle/1/85959Pg, ThesisThe main criterion for food selection is colour. Some synthetic colours are detrimental to human health and hence food industry is looking for natural pigment. Rhodotorula is a carotenoid biosynthetic yeast producing yellow or orange red colonies. The present study was taken up for characterization of Rhodotorula from various dairy environmental sources, screening the isolates for pigment production and characterization of pigment obtained. Among dairy environmental samples, air sample showed highest count (3.47 log cfu/min) followed by apple and can milk. Rhodotorula isolates of 11 were from air (3), apple (4), can milk (2) and yoghurt (2). Identification revealed 3 isolates as Rhodotorula minuta, while 2 isolates as Rhodotorula acheniorum and 6 as unidentified isolates as they did not match with identification key. All the isolates of Rhodotorula were screened for pigment production based on urea hydrolysis Rhodotorula minuta RAI3; Rhodotorula acheniorum RC2, Rhodotorula sp RA2, Rhodotorula minuta RY1 were further selected for pigment production isolated from air, can milk, apple and yoghurt respectively Sterile synthetic media Malt Yeast Extract Agar (MYEB), coconut water as liquid media and rice as solid substrate medium were used for extra and intra cellular pigment production from Rhodotorula minuta RAI3; Rhodotorula acheniorum RC2, Rhodotorula sp RA2, Rhodotorula minuta RY1. Coconut water and rice media showed maximum production of extra and intracellular pigment at 300C for 6 days. Among the 4 isolates, Rhodotorula minuta RAI3 showed maximum extra and intra cellular pigment production of 2.877μg/g and 4.412 μg/g of dry cell mass respectively. Lab pasteurization (630C/30min), boiling (1000C/10min) and sterilization (1210C/15 min) reduced the intensity of extra and intracellular pigment of Rhodotorula minuta RAI3. The pigment stability was noticed at pH 7 compared to acidic and alkaline pH. The stability of extra and intracellular pigments was observed both at room temperature (290C) and refrigeration temperature (40C) upto 15 days of storage. Three fractions with Rf values of 0.19, 0.65 and 0.84 for extracellular pigment and 0.21, 0.70 and 0.90 for intracellular pigment was noticed in thin layer chromatography with benzene: petroleum ether (95:5) as mobile phase that may reveal the presence of - carotene torularhodin and torulene based on their Rf values respectively.enCharacterization of Pigments from Wild Strains of RhodotorulaThesis