Abstract: The freezing point of milk is in important indicator of
the milk quality. The freezing point of milk is determined primarily
to prove milk adulteration with water and to determine the amount of
water in it. Chemical composition and properties of milk, thermal
treatment and presence of any substance can influence freezing point
of product. There are different substances, which can be added to
milk with main purpose to prolong shelf-life of raw milk. There are
detergent, preservatives, formaldehyde, hydrogen peroxide,
antibiotics, sodium carbonate, and hydrogen peroxide. Therefore the
aim of the present study was to determine freezing point of milk,
skimmed milk, pasteurized milk and milk with different substances
(formaldehyde, antibiotics, sodium carbonate, hydrogen peroxide,
disinfectant, and detergent) in different concentrations. The thermal
treatment and different undesirable substances presence in milk have
significant influence on freezing point of it.
Abstract: The influence of lactulose and inulin on rheological
properties of fermented milk during storage was studied.Pasteurized
milk, freeze-dried starter culture Bb-12 (Bifidobacterium lactis, Chr.
Hansen, Denmark), inulin – RAFTILINE®HP (ORAFI, Belgium) and
syrup of lactulose (Duphalac®, the Netherlands) were used for
experiments. The fermentation process was realized at 37 oC for 16
hours and the storage of products was provided at 4 oC for 7 days.
Measurements were carried out by BROOKFIELD standard methods
and the flow curves were described by Herschel-Bulkley model.
The results of dispersion analysis have shown that both the
concentration of prebiotics (p=0.04
Abstract: the obligatory step during immunoglobulin and lysozyme concentration process is thermal treatment. The combination of temperature and time used in processing can affect the structure of the proteins and involve unfolding and aggregation. The aim of the present study was to evaluate the heat stability of total Igs, the particular immunoglobulin classes and lysozyme in milk. Milk samples were obtained from conventional dairy herd in Latvia. Raw milk samples were pasteurized in different regimes: 63 °C 30 min, 72 °C 15-20 s, 78 °C 15-20 s, 85 °C 15-20 s, 95 °C 15-20 s. The concentrations of Igs (IgA, IgG, IgM) and lysozyme were determined by turbodimetric method. During research was established, that activity of antimicrobial proteins decreases differently. Less concentration reduce was established in a case of lysozyme.
Abstract: Consumer demand for products with low fat or sugar content and low levels of food additives, as well as cost factors, make exopolysaccharides (EPS) a viable alternative. EPS remain an interesting tool to modulate the sensory properties of yoghurt. This study was designed to evaluate EPS production potential of commercial yoghurt starter cultures (Yo-Flex starters: Harmony 1.0, TWIST 1.0 and YF-L902, Chr.Hansen, Denmark) and their influence on an apparent viscosity of yoghurt samples. The production of intracellularly synthesized EPS by different commercial yoghurt starters varies roughly from 144,08 to 440,81 mg/l. Analysing starters’ producing EPS, they showed large variations in concentration and supposedly composition. TWIST 1.0 had produced greater amounts of EPS in MRS medium and in yoghurt samples but there wasn’t determined significant contribution to development of texture as well as an apparent viscosity of the final product. YF-L902 and Harmony 1.0 starters differed considerably in EPS yields, but not in apparent viscosities (p>0.05) of the final yoghurts. Correlation between EPS concentration and viscosity of yoghurt samples was not established in the study.