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1. Effect Of Various Concen Trayious Of Hydrogen Pereoxide On Chemical And Microbiogical Quality Of Raw Buffalo Milk

by Muhammad Ilyas Alam | Prof. Dr. Muhammad Ayaz | Dr. Aftab Ahmed Anjum | Dr. Imran Javed.

Material type: book Book; Format: print Publisher: 2011Dissertation note: Milk is a complex mixture of fat, proteins, carbohydrates, minerals, vitamins and other miscellaneous constituents dispersed in water. Milk production in flush season is much more than in the normal. Milk production and supply fluctuate through out the year and during winter it is surplus to its demand. Surplus milk is available in winter due to new calving, less consumption of milk by the consumer. In winter season ample amount of green fodder is available to the animals which in turn increase the milk production. Milk and milk products being very delicate and perishable food require special handling prior to the consumption and further treatment. Pakistan due to its harsh climatic conditions people are using different methods, for the preservation of milk. They are using different chemicals, additives and antibiotics to enhance the keeping quality of milk. Present study was planned to investigate the various concentration of hydrogen peroxide or raw buffalo milk and its effect on chemical and microbiological quality of raw buffalo milk. Raw buffalo milk samples were collected from Dairy Animal Training and Research Centre, University of Veterinary and Animal Sciences, Ravi campus Pattoki Fifty samples of raw buffalo milk (100ml each) were collected to studied the nutritional composition and microbiological quality of the milk after adding the hydrogen peroxide. The hydrogen peroxide of different concentration i.e. 0.025%, 0.05%, 0.075%and 0.1% were used in this study. There was no significant change in the result regarding various nutritional composition of raw buffalo milk after adding the various concentrations of hydrogen peroxide. There is a slight change in the lactose % during study of 48 h storage of milk at different temperature. Statistically the change which occurred in lactose during storage is significant whereas over all decrease in Solid Not Fat is non significant Mean value of TPC of raw buffalo milk treated with different concentrations of hydrogen peroxide storage at the three different temperatures indicated that at 10° C TPC was very less as compared to control. TPC at 30° C after 48 h was 9.83x106.Which was very less as compared to TPC of control i.e. 1.195 x107. The effect of H2O2 on the quality of the milk is negligible as compared to the losses suffered without it. The hydrogen peroxide definitely have its effect as a preservative.. The use of preservative in milk and dairy products are not new in the countries where ambient temperature remains quite high. Our study suggests that the concentration of hydrogen peroxide to be used for the preservation of raw milk is 0.05 % to 0.1 % Availability: Items available for loan: UVAS Library [Call number: 1291,T] (1).

2. Development Of Cheddar Cheese By Using Crude Flowers Extract Of Citrus Aurantium (Sour Orange) As A Milk Coagulant

by Usman Mir Khan (2009-VA-510) | Mr. Ishtiaque Ahmad | Prof. Dr. Muhammad Ayaz | Mr. Hifz-ul-Rahman.

Material type: book Book; Format: print ; Literary form: not fiction Publisher: 2015Dissertation note: Presently in Pakistan a few dairy companies are producing Cheddar cheese. Several alternative proteases obtained from different vegetable and fruit sources such as fruits, roots, latex and flowers have been recommended as rennet coagulant replacer in cheeses processing. As there is now decrease in slaughtering of young calves, natural rennet shortage occurs, so to fill it, sometimes alternates of rennet used in cheese production technology. This research project was designed to implement and introduce the use of Citrus aurantium crude flower extracts (CFE) as an economical, easily available and rennet substitute in Cheddar cheese production. CFE was evaluated for its first time usage as coagulant in Cheddar cheese production and compared with rennet for its physicochemical characteristics and sensory evaluation. Cheddar cheese was made from buffalo milk. Standardized buffalo milk was pasteurized and then cooled to inoculation temperature. It was inoculated with addition of 2% of starter culture and given stay of 20-50 minutes. Then control sample was coagulated with 0.002% rennet and other samples were coagulated by Citrus aurantium crude flower extracts (CFE) at different levels of 1%, 2 %, 3% and 4% at coagulation time. After curdling, curd was cut, stirred and whey was drained. Then milling and cheddaring of cheese blocks was done. Salting was done at the rate of 2.5%. After pressing, cheese was stored in hygienic packaging and left for ripening at 10°C for 2 to 3 months. Acceptability of newly developed Cheddar cheese using crude flower extracts (CFE) as a coagulant was evaluated by sensory evaluation using criteria of color, Cheddar cheese Summary 49 samples were analyzed for physico-chemical characteristics and sensory evaluation at 63 days of storage. The statistical analysis was carried out by using one way Analysis of Variance (ANOVA) techniques under (CRD) Completely Randomized Design (Steel et al. 1987). Duncan’s Multiple Range (DMR) Test was used for significant difference comparisons (SAS 9.1 Statistical Software). The cheese prepared from using 1% and 4% CFE cheese showed higher fat contents from 0 to 63 days while CFE cheese prepared with 1% and 3% have significant fat contents and less than control sample prepared with rennet. Cheddar cheese with %, 2% and 3% showed similar 25% protein content respectively but less than 4% and rennet coagulated standard Cheddar cheese. Cheddar cheese made from 2% and 1% CFE showed slightly higher moisture content while 3% and 4% showed moisture content of 33% almost similar to the rennet coagulated Cheddar cheese which showed 32% of moisture content. The cheese prepared from using 4% CFE cheese showed highest pH of 5.57 at 0 days while after storage at 63 days pH decreased to 5.52. CFE Cheddar cheese prepared with 1%, 2% and 3% showed pH of 5.55 at 0 days and decreased to 5.52 which is standard pH of the Cheddar cheese. Salting of all cheese samples was done at the rate of 2.5%. The cheese prepared from using 2% and 3% CFE showed decrease in salt but it was higher than 1% and controlled Cheddar cheese. While 4% showed lower salt contents than all cheeses. Results showed that cheeses were made with 1% and 2% of CFE had a longer and slightly softer texture. While cheeses contained 3% and 4% CFE had semi-hard textural properties of curd similar to rennet added cheese which is similar to the standard Cheddar cheese made with rennet. Cheddar cheese with 3% and 1% were preferred by consumers instead of 2% and 4% for their better taste, texture/appearance and overall Summary 50 acceptability but it was less preferred over standard Cheddar cheese (controlled) due to the presence of bitter and intense aroma compounds of Citrus aurantium flowers. It will give a benefit to the cheese industry by introducing a new economical, nutritional and easily available rennet substitute source of milk coagulation. Pakistan is producing largest amount of Citrus aurantium, so it will improve its export in other countries for usage as an alternate of rennet and to provide economic benefits to our country. Furthermore, it will open new ways for researchers to find out the characterization of extract and enzyme of CFE. Availability: Items available for loan: UVAS Library [Call number: 2302-T] (1).



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