Designing turbulence promoters with optimal geometry and using them for ultrafiltration systems has been a key challenge in mitigating membrane fouling. In this study, six different turbulence promoters were created using three-dimensional printing technology and applied in dead-end ultrafiltration. Three-dimensional-printed (3DP) turbulence promoter configurations were integrated into a classical batch ultrafiltration cell. The effects of these configurations and the stirring speeds on the permeate filtration flux, organic rejections, and membrane resistances were investigated. The fouling control efficiency of the 3DP promoters was evaluated using two polyethersulfone membranes in a stirred ultrafiltration cell with model dairy wastewater. The Hermia and resistance-in-series models were studied to further investigate the membrane fouling mechanism. Of the Hermia models, the cake layer model best described the fouling in this membrane filtration system. It can be concluded that the 3DP turbulence promoters, combined with intense mechanical stirring, show great promise in terms of permeate flux enhancement and membrane fouling mitigation. Using a well-designed 3DP turbulence promoter improves the hydrodynamic flow conditions on the surface of the stirred membrane separation cells based on computational fluid dynamics modeling. Therefore, the factors effecting the fabrication of 3DP turbulence promoters are important, and further research should be devoted to revealing them.
In this study, the enzyme-induced and acid coagulation of raw milk samples were investigated, and these two processes were monitored by determining the changes in dielectric and rheological behavior to see if any correlations could be found between these two properties. For the enzyme-induced experiments, 250 cm3 of raw milk sample and industrial chymosin were used, and during the acid coagulation, industrial thermophile yogurt culture was added to the same amount of milk. The apparent viscosity was monitored with a vibro viscometer, and the dielectric constant was measured in a frequency range of 200–2400 MHz with an open-ended dielectric assessment kit (DAK) connected to a vector network analyzer (VNA). Our experimental findings revealed that during both enzyme-induced and acid coagulation, two distinct phases could be found in terms of dielectric and rheological properties, and regardless of the molecular mechanisms behind the aggregation of casein micelles, a strong correlation (with R2-values ranging between 0.967 and 0.992) can be found between the extent of the apparent viscosity and dielectric constant, suggesting that dielectric measurements might be adequately used in these dairy processing technologies. These results verified the applicability of the non-destructive dielectric measurements in dairy technologies.
1 November 2018 in Advanced Research in Life Sciences
A total of 46 Swiss alpine does were examined. We analysed the composition of the milk and evaluated the body condition of the animals (BCS: 0.5 to 4.5 scale) on the same day in the last third of lactation. Goats were grouped according to their body condition for statistical calculations. We found that there was a statistically detectable relationship between body condition and milk composition of the goats. Together with the increase of BCS, the fat, protein and mineral contents in the milk increased as well. Significantly more fat, protein and mineral contents were found in the milk (6.01%;3.55%; 0,98%) in case of the well-conditioned (BCS 3.5) animals than in the thin ones (BCS 1.5-2) (4.56%, 3.11%, 0.77%) (P<5%). The concentration of milk sugar was similar between thin and better conditioned groups of animals, so the body condition did not affect these values. The importance of our study is that, the high fat and protein content of milk increases the yield of dairy products. If the animals can produce milk that has higher fat and protein content, than we can produce more dairy products that will bring more economic benefits. The aim of our study was to evaluate the effects of body condition on milk yield and quality (milk composition) in dairy goats.
More researches published data about the milk curd properties, evaluated the importance in the cheese making, but an analysis of importance of these properties in practical applications is usually lacking. We investigate the milk curd behaviour using different enzyme preparations at the cutting of curd. We focused on the well measurable properties as clotting time, viscosity of curd, texture properties an whey separation rate of cur at cutting time. Approximately five minutes difference was determined between the clotting times. Investigated the curd properties we found significant differences between the hardness on samples clotted with CHY MAX® M 1000 and NATUREN® Premium 145 enzymes. Other properties did not show significant differences, but in some case differences were remarkable. Discovered differences e.g. approx. 5% whey separation rate difference and the different trends of adhesive force and adhesiveness confirm that such studies should be carried out. Summarized effect of different enzymes can alter the cheese making technology in the practice, significantly. Considering every aspect, in our investigation the CHY MAX® M 1000 enzyme seemed the best.