Browsing by Subject "homogenointi"

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  • Koivusaari, Katariina (Helsingfors universitet, 2017)
    Milk production in Finland has changed during the latest decades. There are significant changes in cattle breeding, cattle feeding, milk collecting and transportation. Also processing of milk products has been developed. In addition, milk products are consumed in a different way than before. For example the consumption of fat-free milk and cheeses has increased whereas overall consumption of milk has decreased. In this master’s thesis milk products of DIPP (Diabetes Prediction And Prevention) nutrition study were classified based on their homogenization and heat-treatment. Creating the classification, the effects of heat-treatment or homogenization on milk proteins and fat globules were considered. The classification was done using information provided by literature and by major dairy manufacturers. Milk products were classified in one of the following groups based on the homogenization information: homogenized, non-homogenized, fat-free; and in one of the following groups based on the heat-treatment information: normally pasteurized or milder heat treatment, high pasteurized at < 100°C, high pasteurized or sterilized at ≥100°C. Milk consumption of children at the age of 6 months (n=1305), 1 year (n=1513) and 3 years (n=1326) was observed using both the updated classical DIPP - milk product classification and the newly created processing based classifications. It was observed that children used a lot of strongly heated milk-based products especially during their first year. At the age of six months mostly high pasteurized or sterilized at ≥100°C and homogenized milk products were used. Background variables such as breastfeeding, mother’s education and children’s living area (Pohjois-Pohjanmaa/ Pirkanmaa) were associated with milk product consumption both when using classical and process based classifications. This study introduces new information about children’s milk product consumption. The process based classification can also be used later when observing whether consumption of some specific kind of milk products can lead to appearance of type 1 diabetes.
  • Heikintalo, Noora (Helsingfors universitet, 2012)
    The aim of this study was to find out what new characteristics are possible in Emmental with a novel pre-treatment routine of milk. Homogenization of the milk and its consequent impact on lipolysis affect cheese properties was examined. Cheeses (H0, H50 and H100) were produced from milks, which were homogenized at different pressures (0, 50 or 100 bar) and the control cheese was prepared from unhomogenized milk. Cheeses were ripened for three months. Homogenization of milk causes redistribution of milk fat globules into smaller ones. Physical changes to the milk fat globule membrane allow indogenous lipoprotein lipase to access and breakdown triglycerides of milk releasing free fatty acids, known as lipolysis. The sensory quality of the cheeses were studied with traditional descriptive analysis and the modern Temporal Dominance of Sensations (TDS) method. The chemical composition of cheeses were also determined (moisture, salt, fat and protein content). In addition the degree of lipolysis in the milk, from which cheese was made of, was measured by the acid degree value (ADV) and a fluorimetric lipase assay. Homogenization of milk at 50 and 100 bar modified cheese properties most and homogenization of milk with 0 bar pressure less, compared to the control cheese. According to sensory results, the changes in the texture of cheeses were most significant. As a results of homogenization of milk the texture of cheese changed from elastic to crumbly, greasy and sticky. The cheese flavor changed due to homogenization of milk and the consequent lipolysis to become stronger, saltier and more sour. There were no significant differences in intensity of odour attributes between the cheeses. Homogenization of milk (50 and 100 bar) increased the moisture and salt content and reduced protein content. The differences in fat content between the cheeses were small. Homogenization of milk at 50 and 100 bar pressures exposed milk fat to lipolysis, which was seen as an increase in acid degree values of milk. On the other hand, homogenization of milk (50 and 100 bar) decreased lipoprotein lipase activity in the milk according to the fluorimetric assay. However the residual activity of lipoprotein lipase in milk was strong enough to almost double the amount of free fatty acids in homogenized milk. It can be possible to change texture characteristics of cheese by using homogenization of milk as a part of cheese manufacture. Different texture attributes can be utilized in the development of new types of cheese.