1.
Comparative Study On Physico-Chemical ,Microbiological & Chemical Adulterants Of Raw & Processed Milk.
by Qasim Raza | Prof.Dr. Muhammed Ayaz | Prof. Dr Muhammed Abdullah.
Material type: ; Format:
print
; Literary form:
not fiction
Publisher: 2009Dissertation note: Milk production, handling, storage, transportation and marketing of milk is handled in a primitive way in Pakistan. Mostly middle man and contractors are involved in the collection, marketing and distribution of milk. Most of the milk is produced in rural sareas and transported to cities where it is supplied to milk plants and also to house consumers. During transportation and distribution there is no refrigeration involved. Middle man adds ice to keep the milk cool and prevent from spoilage. In addition, they also add chemical to kill bacteria and prevent spoilage of milk.
Adulteration of milk is one of the most serious issue in the dairy sector of Pakistan, causing not only major economic losses for the processing industry, but also major health risks for the consumers. Milk is a perishable item and to prevent the spoilage of milk various chemicals are added. In addition to that microbiological quality of milk is very important which directly concern not only with milk spoilage but also consumer health
Keeping in view this study the main object of this study is to determine the hysico-chemical, microbiological and adulterants in raw and processed milk available in Lahore. The raw milk samples ware collected from local market of Lahore city Gawalas, Retail milk shops, Small Dairy Farms sale points and Milk Plants collection centers. A total of 80 samples of raw and 40 samples of processed milk were collected from Lahore
Raw milk samples were collected from Retail milk shops and Gowalas at four different locations of Lahore city i.e. Defence, Allama Iqbal Town, Samanabad and Inside the wall city, from Small Dairy Farms sale points Sakhian pul and Shadera Town areas. Five samples were also collected from experimental dairy farm of UVAS and collection centers of 4 companies.
UHT and Pasteurized milk samples of five different brands were collected from Lahore. A total of 120 milk samples were collected for Physico-chemical, Microbiological and Chemical Adulterants study.
Physico-chemical, microbiological analysis and adulterants detection tests were performed in WTO Laboratory , University of Veterinary and Animal Sciences, Lahore. Color, Taste and flavor of most of the samples were found normal in color, taste and flavor except a few samples of raw milk from shops and Gawalas. Temperature of raw milk was ranged from 4.80±0.096 °C to 30.48±0.611 °C. UHT brands were at ambient temperature and Pasteurized milk brands were stored at refrigeration temperature.
Density in raw milk was ranged from 18.100±0.575 to 27.738±0.16203, lowest in Gawalas and highest in UVAS Dairy. In UHT milk ranged from 26.142±0.088 to 28.222±0.3 15 and in pasteurized milk ranged from 26.280±0.527 to 27.377±0.147.
The highest mean of freezing point recorded was -0.325±0.0 10 °C in Gawalas and lowest -0.542±0.003 °C observed in UVAS Dairy milk. URT milk ranged from -0.487±0.006 °C to -0.463±0.007 °C and in pasteurized milk brands ranged from -0.480±0.002 °C to - 0.455±0.008 °C.
Fat in raw milk ranged from 4.038-0.056% to 6.340±0.060% lowest was in shops and highest in UVAS Dairy milk. UHT fat ranged from 3.472±0.006% to 3.492±0.006% and in Pasteurized milk fat ranged 3.452±0.020% to 3.495±0.005%.
SNF in raw milk ranged from 5.386±0.13745% to 8.226±0.026% lowest in Gawalas and highest in UVAS Dairy. In UHT milk fat ranged from 7.465±0.033% to 8.082±0.09151% and in Pasteurized milk SNF ranged from 7.563±0.125% to 7.905±0.023%.
Protein in raw milk ranged from 2.131±0.060% to 3.162±0.017%, lowest was in shops and highest was in UVAS Dairy. In UHT milk protein ranged from 2.99 1±0.026% to 3.2 10±0.038%, in Pasteurized milk protein ranged from3.001±0.053 to 3.146±0.009. Lactose in raw milk ranged from 2.768±0.067% to 4.364±0.041%, lowest was in Gawalas and highest in UVAS Dairy. In UHT milk lactose ranged from 3.827±0.011% to 4.107±0.050%, in Pasteurized milk lactose ranged from 3.870±0.070 to 4.020±0.044.
Ash in raw milk ranged from 0.512±0.017% to 0.786 ±0.004%, lowest was in Gawalas and highest in UVAS Dairy farm. In UHT ash ranged from 0.698±0.0 1 1% to 0.739±0.007%, in Pasteurized milk ash ranged from 0.689±.008% to 0.739±0.007%.
Water added in raw milk ranged from 0 to 36.527±1.945%, lowest was in UVAS Dairy farm and highest Gawalas milk. In UHT water added ranged from 5.939±1.094% tol2.229±0.407% in Pasteurized milk water added ranged from 6.975±0.045% to 12. 150± 1.769%.
pH in raw milk ranged from 6.726±0.019 to 7.052±0.027, lowest was in UVAS Dairy and highest was in Gawalas milk, In UHT milk pH ranged from 6.839±0.019 to 6.870±0.0 19, in Pasteurized milk pH ranged from 6.800±0.024 to 6.886±0.03 1.
Acidity in raw milk ranged from 0.147±0.001% to 0.161±0.000%, lowest was in Gawalas and highest was in Dairy plant collection centers. In UHT milk acidity' ranged from 0.158±0.003% to 0.161±0.003% and in Pasteurized milk acidity ranged from 0.158±0.003% to 0.161±0.003%.To study the microbiological quality, total plate count (TPC), coliform count and S. aureus count were made.
TPC in raw milk ranged from 2.9 x iO± 2.2 x i04 to 1.7 x l0 ± 8.1 x 10± 8.1 x 106. Lowest was in UVAS Dairy farm and highest was in Gawalas milk, in Pasteurized milk TPC ranged from 5.0 x 10±l .2 x i04 to 6.8 x 10±2.3 x 104.
Coliform count in raw milk ranged from 3.1 x i0± 3.0 X 102 to 4.4 x i05 ± 4.3 X i03.
Lowest was 3.1 x i± 3.0 X 102 in UVAS dairy farm and highest was in Gawalas milk.
In Pasteurized milk Coliform count ranged from 58±3.856 to 344±161.272.
Staph aureus Count in raw milk ranged from 6.4 X l0±6.7 X 102 to 8.7 X 10±2.2 X i0
Lowest was in UVAS Dairy farm and highest was in Shops milk, in Pasteurized milk Staph aureus Count ranged from 61.87lO.901 to 276.62±105.178.
All UHT brands were found negative for TPC, Coliform count and Staph aureus count.
The qualitative tests adulterants were performed by (M.A.T). Kit.
In raw milk the major adulterants found were Urea, Formaldehyde, Hydrogen peroxide,
Neutralizers, Boric acid and QAC. All adulterants were found negative in the milk of
UVAS dairy farm.
In UHT and Pasteurized brands the adulterants found were Salt, Sugar, Starch and
Hydrogen peroxide.
Conclusion
On the basis of present finding, it is concluded that multiple factors can markedly affect the quality of milk. Water addition was one of the major adulteration present in every step of milk marketing. All the raw milk samples were found inferior for their Phsicochemical quality. In processed milk the fat percentage was in the normal range while other parameters were inferior. Microbiological contamination was also higher in raw and pasteurized milk samples. Adulteration of milk with chemicals such as caustic soda, urea, formalin, hydrogen peroxide, sugar and salt were also detected in raw and processed milk. The high microbiological contamination and presence of chemical adultrants in raw and processed milk showed that the milk constitutes a potential public health hazard.
Availability: Items available for loan: UVAS Library [Call number: 1062,T] (1).
2.
Effect Of Vegetable Oils Blend On Physico Chemical Sensory Characteristics Of Low Fat Ice Cream
by Gohar Abbas Khan | Prof. Dr. Muhammed Abdullah | Dr. Jalees | Muhammed Nadeem.
Material type: ; Format:
print
Publisher: 2010Dissertation note: Ice cream is the most popular dairy product and equally liked by people of all ages. Milk fat is important to ice cream because t increases the richness of flavor, produces a smooth characteristic texture, gives body to the ice cream and contributes good melting properties. intake of milk fat has been associated with coronary heart disease. Vegetable Cats are used extensively as fat sources in ice cream. Palm oil having low melting point and high iodine value which is also used in ice cream manufacturing as source of vegetable fat. In this research work of ice cream manufacturing, milk fat was replaced with palm oil and sunflower vegetable oil to find out the optimum level at which milk fat could he replaced with vegetable oil blend and to develop a more health friendly ice cream which has lower level of saturated fatty acids and no trans fatty acids.
The experiment was involved in making five types of ice cream and fifteen batches of ice cream were prepared. Mix was heated to 80 °C. homogenized in a clean and sanitized double stage homogenizer. Pasteurized and homogenized mix was cooled immediately to 4 °C and will be aged at this temperature for 24 hours. The mix was then frozen. Analysis of ice cream for chemical tests including pH, acidity, fat, protein, ash, total solids and physical tests including color, flavor, taste and overall acceptability, physical parameters of ice cream for whippingability, hardness, overrun measurement, melting test, viscosity and storage study was determined. The data obtained was statistically analyzed to find out the effect of treatment and storage intervals.
Compositional attributes like fat, protein, ash and total solid contents were not influenced by the addition of vegetable oil blend at all levels i.e from 25% to 100% replacement. Compositional attributes were not influenced by storage period of 60 days. Addition of vegetable oil blend did not have significant effect of pH and acidity of different treatments. During storage of 60 days pH slightly decreased while acidity increased non significantly.
The addition of vegetable oil in different treatments of ice cream tended to decrease the whippingability with increase levels of vegetable oil blend. Whippingability decreased throughout storage period of 60 days in all treatments. Decrease in whippingability may be due to increased level of vegetable oil blend in ice cream. Overrun varied between different treatments of ice cream .The maximum level of overrun was observed in T2 (81.91) and minimum level in T4 (65.11). Decrease in overrun may he due to increased level of vegetable oil blend in mix of ice cream. Effect of storage on treatments was significant. The interaction between treatments and storage was also non significant. Melting resistance varied between different treatments of ice cream and maximum level of melting resistance in T2 (45.83) and minimum level in T0 (2 9.83). l) Decreased in melting resistance may be due increase level of vegetable oil blend in mix of ice cream.
Flavor of different treatments of ice cream varied significantly among each other and the maximum score for flavor was in T2 (8.08) and minimum in T4 (6.74). Flavor slightly decreased throughout storage period of 60 days in all treatments. Statistical data for color of different treatments of ice cream indicated that all treatments varied significantly among each other and the maximum score for flavor was in T2 (8.97) and minimum in 14 (5.64). Color slightly decreased throughout storage period of 60 days in all treatments. The mean scores for taste of modified vegetable fat in different treatments of ice cream showed that maximum level of score of taste was in 12 (8.23) and minimum in 14 (5.89). Decline in flavor score may be due to increase in modified vegetable oil in ice cream.
Overall acceptability scores were affected significantly with different treatments of ice cream with modified vegetable fat addition and storage interval and also significant. Judges placed 12 (8.08) at the top which differed significantly with other treatments of ice cream while the lowest mean overall acceptability scores were assigned to '1,4 (5.77). Storage also had significant effect on overall acceptability scores. The main objective of this research work was to replace milk fat with vegetable oil blend in the production of ice cream. Replacement of milk fat at 12 level i.e (50% milk fat and 50 % vegetable oil blend) did not have adverse effect on fat, protein,ash, total solids, pH and acidity of ice cream. As evident from the sensory scores T2 obtained maximum score for color, flavor, taste and overall acceptability and did not influence significantly from control. It is concluded that satisfactory quality ice cream can be manufactured by replacing 50% milk fat with 50% vegetable oils blend
Availability: Items available for loan: UVAS Library [Call number: 1152,T] (1).
