Study On Chemical Composition Of Nili Ravi Buffalo Milk
Material type: Book ; Format:
; Literary form:
Publisher: 2010 Dissertation note: Milk is a complete food and contains all the nutritional components in balanced form. It helps to meet important nutritional needs of the human body. Vitamins, minerals, sugar, Fat, and protein are present in milk. Among the established breeds of buffalo in Pakistan. the Nili-Ravi breed originated in the valleys of Sutlej and Ravi rivers is dominant in the Punjab province. The purpose of the study is to determine the chemical composition and fatty acid profile of buffalo milk.
The milk animals, Buffaloes were divided into 3 groups on the basis of lactation period i.e early, middle and late lactation. Five animals were present in each group. Six milk samples. 3 in the morning and 3 in the evening from each animal was collected. A total of 90 milk samples were obtained for analysis. Milk in bottles of 500 ml capacity was transported to lab. [he samples were analyzed in Livestock Production Research Laboratory, Livestock Production Research Institute Bahadurnagar (Okara). Temperature, Density, Conductivity and freezing point was determined by using Milkoscan.
Buffalo samples were analyzed for proximate analysis, parameters like fat, crude protein, lactose, ash, solids not fat, total solids, pH and acidity were determined. Fatty acid profile of buffalo milk was determined by the method of AOAC (2000). Milk fat content (%)was Ihund to be significantly (p<0.05) lower in the early (6.52) and mid lactation (6.61) stages than the late lactation stage (6.85). The content of TS (%) was found to be significantly (p<O.05) higher in the late lactation (14.62 and 15.45) stage than the early (12.94 and 13.65) and mid lactation (13.76 and 14.14) stages. In contrast, the content of total protein (4.31 to 4.78%), SNF (X.4() to8.70%), lactose (4.36 to 4.74%), and ash (0.l8to 0.19%) did not vary significantly among the different lactation stages.
Fatty acids profile also checked from Cl to C20. The values of Butyric acid, Caproic acid. Myristic acid, Stearic acid, and Oleic acid showed significant increase towards end of lactation. 'lhcse values of fatty acids also revealed that there is significant difference among the animals and between the lactation stages of Nih- Ravi buffalo milk. Results showed that Capric acid, Laurie acid, Palmitic acid, Palmitoleic acid, Linoleic and Linolenic acid decreased in early to middle and increased towards end of lactation.
Availability: Items available for loan: UVAS Library [ Call number: 1220,T] (1).
Effect Of Replacing Milk Fat With Chemically Interesterified And Enzymatically Transesterified Palm Olein on Physico-Chemical and Sensory Characteristics of Ice Cream
Material type: Book ; Format:
; Literary form:
Publisher: 2009 Dissertation 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 it 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 fats are used extensively as fat sources in ice cream. Functional properties of vegetable oils are modified by the process of hydrogenation. Palm olein is a fraction of palm oil having low melting point and high iodine value which is also used in ice cream manufacturing as source of vegetable fat. Physico-chemical characteristics of vegetable oils and fats can also be modified by interesterification. It is an acyl-rearrangement reaction on the glycerol molecule and may either be random or selective. Interesterification can be carried out chemically and enzymatically. Sodium Methylate is used in chemical interesterification. In enzymatic interesterification microbial lipases is used as the catalyst. In this research of ice cream manufacturing, milk fat was replaced with interesterified palm olein in to find out the optimum level at which milk fat could be replaced with interesterified palm olein 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 ten types of ice cream and thirty batches of ice cream was 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 skim milk powder for moisture, fat, acidity, protein, lactose and ash, analysis of milk fat for fat, free fatty acids and acidity, analysis of palm olein before and after interesterification for free fatty acids, iodine value, peroxide value, melting point, color and moisture, 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 effect of storage on treatment.
Compositional attributes like fat, protein, ash and total solid contents were not influenced by the addition of chemically interesterified and enzymatically transesterified palm olein at all levels i.e from 25% to 100% replacement. Compositional attributes were not influenced by storage period of 60 days.Addition of either chemically interesterified palm olein or enzymatically transesterified palm olein 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 chemically interesterified and enzymatically transesteified palm olein. Statistical data represented that highest level of whippingability was T2 (1.185) and minimum level in T9 (0.913). Whippingability decreased throughout storage period of 60 days in all treatments. Decrease in whippingability may be due to increase level of unmodified palm olein in ice cream. Overrun varied between different treatments of ice cream and maximum level of overrun in T2 (83.482) and minimum level in T9 (65.635). Decrease in overrun may be due increase level of chemically interesterified and enzymatically transesteified palm olein in mix of ice cream. Effect of storage on treatments was significant. The interaction between treatments and storage was also significant. Melting resistance varied between different treatments of ice cream and maximum level of melting resistance in T2 (39.660) and minimum level in T9 (21.667). Increase in melting resistance may be due increase level of chemically interesterified and enzymatically transesteified palm olein 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 (7.95) and minimum in T9 (6.56). 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 (8.07) and minimum in T9 (5.65). 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 T2 (8.04) and minimum in T9 (4.65). 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 T2 (7.95) at the top which differed significantly with different treatments of ice cream while the lowest mean overall acceptability scores were assigned to T9 (5.56). Storage also had significant effect on overall acceptability scores. The main objective of this research work was to replace milk fat with chemically interesterified and enzymatically transesterfied palm olein in the production of ice cream. Replacement of milk fat at T2 level i.e (50% milk fat and 50 % chemically interesterified palm olein) and T7 (25% milk fat and 75% enzymatically transesterified palm olein) did not have adverse effect on fat, protein,ash, total solids, pH and acidity of ice cream. As evident from the sensory scores T2 and T7 (50% milk fat and 50 % chemically interesterified palm olein) and T7 (25% milk fat and 75% enzymatically transesterified palm olein) 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% chemically interesterified palm olein and 25% milk fat with 75% enzymatically transesterified palm olein.
Availability: Items available for loan: UVAS Library [ Call number: 1108,T] (1).