Infusion pasteurization of whole milk and skim milk: Influence on viscosity and particle size

Infusion pasteurization was performed on both whole milk and skim milk and at different temperatures in the range 72°C-120°C. The skim milk was prepared at a commercial dairy and had been heated to approx. 60°C during the separation process. The whole milk was skimmed by centrifugation prior to the analyses. In the analyses, the infusion pasteurized samples were compared to a standard low pasteurization on the same batches of milk and samples of the raw milks. Particle sizes were analyzed using dynamic light scattering, and the viscosity of the samples were measured with a capillary viscometer. The viscosity measurements showed no significant changes in viscosity after infusion pasteurization of skim milk, nor did the particle sizes change. On the other hand, when whole milk was infusion pasteurized an increase in viscosity of the skim milk fraction was seen as treatment temperature increased, and an increase in the z-average diameter of particles and broadening of the size distributions was observed. These observations were quite surprising and might be the result of influence of several different processes during and after infusion pasteurization

Infusion pasteurization of skim milk: Effects of different time-temperature combinations

Infusion pasteurization technology was used in different time-temperature combinations for heat treatment of skim milk and compared to untreated skim milk and a standard pasteurization treatment. Aerobic count of microorganisms and activity of alkaline phosphatase showed that all infusion-pasteurized samples had received proper pasteurization. There were no difference in the size of casein micelles, but differences were seen in activity of the enzyme xanthine oxidase. The results indicate possible differences in properties of infusion-pasteurized skim milk compared to standard pasteurized skim milk

Permanental processes from products of complex and quaternionic induced Ginibre ensembles

We consider products of independent random matrices taken from the induced Ginibre ensemble with complex or quaternion elements. The joint densities for the complex eigenvalues of the product matrix can be written down exactly for a product of any fixed number of matrices and any finite matrix size. We show that the squared absolute values of the eigenvalues form a permanental process, generalising the results of Kostlan and Rider for single matrices to products of complex and quaternionic matrices. Based on these findings, we can first write down exact results and asymptotic expansions for the so-called hole probabilities, that a disc centered at the origin is void of eigenvalues. Second, we compute the asymptotic expansion for the opposite problem, that a large fraction of complex eigenvalues occupies a disc of fixed radius centered at the origin; this is known as the overcrowding problem. While the expressions for finite matrix size depend on the parameters of the induced ensembles, the asymptotic results agree to leading order with previous results for products of square Ginibre matrices.Comment: 47 pages, v2: typos corrected, 1 reference added, published versio