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Theses (PG)

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20116
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Subject: Dairy Microbiology × End date: 2011 × Start date: 2011 ×
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Now showing 1 - 6 of 6
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    ThesisItemOpen Access
    CHARACTERIZATION OF PIGMENTS FROM WILD STRAINS OF RHODOTORULA
    (Karnataka Veterinary Animal And Fisheries Sciences University, Bidar, 2011) SHIVALKAR YADAV, K
    The development of foods with an attractive appearance is an important goal in the food industry
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    ThesisItemOpen Access
    COMPARATIVE EVALUATION OF MICROBIAL PLATFORM TESTS WITH STANDARD PLATE COUNT IN MILK
    (Karnataka Veterinary Animal And Fisheries Sciences University, Bidar, 2011) ARUNA, V.B.Tech (D.Tech)
    India, the highest producer of milk in the world has great potentiality to top the emerging global marketing opportunities
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    ThesisItemOpen Access
    PRODUCTION OF DIRECT VAT SET DAHI CULTURES
    (Karnataka Veterinary Animal And Fisheries Sciences University, Bidar, 2011) DEEPA, B.G.B.Tech (D.Tech)
    Dairying has played a prominent role in strengthening of the Indiaâ s rural economy.
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    ThesisItemOpen Access
    Characterization of Pigments from Wild Strains of Rhodotorula
    (Karnataka Veterinary, Animal and Fisheries Sciences University, Bidar, 2011-06-15) Shivalkar Yadav, K.; Prabha, R.; Krishna, R.; Manjunatha, H.; Venkateshaiah, B.V.; Narasimha Murathy
    The 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.
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    ThesisItemOpen Access
    Comparative Evaluation of Microbial Platform Tests with Standard Plate Count in Milk
    (Karnataka Veterinary, Animal and Fisheries Sciences University, Bidar, 2011-06-15) Aruna, V.; Manjunatha, H.; Krishna, R.; Prabha, R.; Venkateshaiah, B.V.; Kempanna, C.
    The quality of milk has high relevance to its physical, organoleptic, chemical and microbiological properties as well as to its safety. Keeping the quality satisfactorily can bring about high nutritive value of milk which is free from disease producing organisms. In order to determine the relationship between the titratable acidity, dye reduction tests, direct microscopic count, total bacterial count and coliform count, the present study was undertaken by collecting the raw milk samples at various stages of milk production from KVAFSU dairy farm and market milk; chilled milk and pasteurized milk from student experimental dairy plant, Dairy science college, Hebbal, Bengaluru and market milk from local market of Bengaluru. Raw milk samples such as Aseptic, pail, can and chilled milk samples showed a mean titratable acidity ranging between 0.14 and 0.17%, MBRT of 1.70 and 8.2 h, disc number of 6 and 4 for RRT 10 min and 1 h. respectively Viable bacterial log count of 3.24 – 5.95 per ml and coliforms of 0.20 – 4.63 per ml. Significant difference was noticed among parameters tested and also among the types of raw milk and market milk samples. Positive correlation among TBC : DMC (r = 0.994) was found among the tests conducted for the quality assessment of milk samples. All the raw milk samples (Aseptic, pail, can, chilled milk) and market milk samples were subjected to shelf life study by storing at room temperature (260C) and refrigeration temperature (60C). Aseptic milk, pail milk, can milk, chilled milk, market milk samples (B1 to B4) showed keeping quality of 18, 11, 9, 8, 26 ½ h respectively at ambient temperature and positive correlation of r = 0.932 was noticed between TBC and DMC at room temperature among milk samples at refrigeration temperature (40C), Aseptic milk, pail milk, can milk, chilled milk and market milk samples showed keeping quality of 36, 25, 20, 16 and 30 ½ h respectively. Positive correlation of r = 0.573 was noticed between TBC and MBRT at refrigeration temperature among the milk samples.
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    ThesisItemOpen Access
    Production of Direct Vat Set Dahi Cultures
    (Karnataka Veterinary, Animal and Fisheries Sciences University, Bidar, 2011-07-15) Deepa, B.G.; Manjunatha, H.; Krishna, R.; Prabha, R.; Venkateshaiah, B.V.; Kempanna, C.
    Dahi is an important fermented milk product having heterogeneous lactic microflora which play a major role in human diet. Liquid culture is normally used in the preparation of Dahi where microbial contamination with sequential propagation of liquid culture are the noted limitations. Dried and frozen cultures show lower viability and in order to overcome these problems, Direct Vat Set cultures are slowly introduced in the commercial sector. The present study was carried out to develop Direct Vat Set Dahi cultures through solid sate fermentation technique. Dahi samples of 5 each were collected from houses and local markets of Bengaluru. That showed total lactic bacterial viable count ranging from 5.36 to 7.04. Among 72 lactic isolates obtained. lactobacilli predominated (38) followed by leuconostoc (18); lactococci (9) and streptococci (7). The lactic cultures that set the milk with higher direct microscopic counts in sterile skim milk were Leuconostoc sp. Leu6: L. lactis ssp. lactis Lc1: L. fermentum Lb8: S. thermophilus St3 especially at the ratio of 0.15 %: 0.3 %: 0.5%: 1 %. The growth of mixed dahi culture on sterile black gram dhal with 1% skim milk powder, 10% tomato juice and 70% moisture as solid substrate medium showed 9.42 log10cfu/g at 24 hrs of incubation. SSF Dahi culture or DVS Dahi culture at ambient and refrigeration temperature revealed viable count reduction in total lactic count by 4.5 log and 3.5 log by the end of 70 days and 60 days of storage respectively. Dahi prepared from refrigerated stored DVS culture scored better than Dahi prepared out of ambient temperature stored DVS culture.