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Theses

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1980 - 19812
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Subject: Dairy Science × End date: 1984 × Start date: 1980 × Type: Thesis ×
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    ThesisItemOpen Access
    Determination of solids content of milk by specific gravity lactometer
    (Department of Dairy Science, College of Veterinary and Animal Sciences, Mannuthy, 1980) Babu, Mathew; KAU; Subramaniam, M
    The methods of estimating total solids content of milk having high percentage by Richmond’s formula (TS = 0.25 L + 1.2 F + 0.14) using Quevenne’s specific gravity lactometer, modified Richmond’s formula (TS = 0.25 L + 1.2 F + 0.50) using Zeal specific gravity lactometer, ISI formula (TS = 0.25 DH + 1.22 F + 0.72) and Ling formula (TS = 0.25 DH + 1.21 F + 0.66) using the density hydrometer, along with the percentage of fat estimated by Gerber method were compared with the value obtained by gravimetric method using 307 samples of milk. In all the milk samples analysed the calculated values of total solids by the formula methods were both higher and lower than the gravimetric values. Since the formulae methods did not give a true estimate of the total solids in milk, modifications to the existing formulae were required by applying a correction factor. It was observed that depending up on the percentage of fat in milk samples, different correction factors were needed to be applied to the different formulae for getting the values close to the gravimetric method. Addition of a correction factor of 0.15 and 0.18 was necessary to the Richmond’s formula for milk samples containing 5.1 to 6.0 and 6.1 to 7.0 per cent fat respectively. For the modified Richmond’s formula, addition of 0.57, 0.53, 0.66 and 0.75 was necessary for samples containing 3.0 to 4.0, 4.1 to 5.0 and 5.1 to 6.0 and 6.1 to 7.0 per cent fat. The addition of a correction factor of 0.16 to the ISI formula was essential for samples containing 4.1 to 5.0 milk fat to get the values in agreement with the gravimetric method. No correction factor was necessary, if Ling formula was used. The order of preference for using various formulae will be (1) Ling formula (2) ISI formula (3) Richmond’s formula (4) modified Richmond’s formula. Ling formula can be used without any correction factor for determination of total solids content of milk for varying percentages of fat from 3..0 to 9.0.
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    ThesisItemOpen Access
    Properties of milk fat of crossbred goats
    (Department of Dairy Science, College of Veterinary and Animal Sciences,Mannuthy, 1981) Baby George, KAU; Subrahmanyam, M
    An investigation was carried out to determine some of the physical and chemical properties of the milk fat of crossbred goats viz. Alpine x Malabari and Saanen x Malabari. A total of 183 milk samples were collected from six each of the two different crossbred goats and out of this 65 samples were used for determination of the size of the milk fat globules. The various fat constants were determined by analyse of ghee prepared by direct heating of cream separated out from the collected milk samples. The average size of the milk fat globule of Alpine x Malabari and Saanen x Malabari was 2.556+ 0.110 and 2.702 + 0.038 microns respectively. The average value obtained for the melting point of Alpine and Saanen crossbred goats’ milk fat was 31.07 + 0.160 C and 31.36 + 0.130 C respectively. The Alpine crossbred goats’ milk fat gave a refractive index of 1.4568 + 0.0001 and an iodine number of 24.95 + 0.28, whereas the corresponding values obtained for the milk fat of Saanen x Malabari goats were 1.4569 + 0.0001 and 25.09 + 0.35. The Reichert-Meisal(RM) number and polensite value obtained for the milk fat or Alpine x Malabari goats were 28.14 + 0.18 and 3.52 + 0.15 respectively. The corresponding values for the Saanen crossbred goats’ milk fat were 28.61 + 0.15 and 3.64 + 0.12 respectively. The Alpine x Malabari and Saanen x Malabari goat milk fat gave an average saponification value of 235.1 + 0.7 and 234.6 + 1.1 respectively. On statistical analysis of the data it has been found that there was no significant difference between the size of the fat soluble and the various other physical and chemical constituents of milk fat of the two groups of crossbred goats. Towards the end of the lactation highly significant increased was noticed in the melting point, refractive index, iodine number, Reichert-Meisal number and polensite value and decrease in the size of the milk fat globule and saponification value of the milk fat of both the Alpine x Malabari and Saanen x Malabari goats.