Milk Powder Production via Microfiltration and Controlled Pasteurization
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Solution Overview
Problem
Existing methods for producing low-germ whole milk powders either denature valuable whey proteins with high-temperature processes or result in products with high bacterial loads when using lower temperatures, making it difficult to achieve both germ-free and high whey protein index (MPI) values.
Innovation Solution
A process involving microfiltration of skimmed milk, pasteurization, and controlled temperature treatment at 72-80°C to separate germs and preserve whey proteins, followed by drying, which allows for the production of low-germ milk powders with a high MPI without the need for ultra-high heating.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If high-temperature heating is applied to destroy germs and spores, then the bacterial load is reduced to acceptable levels, but the whey proteins are denatured and the MPI decreases to below 1
Solution Approach 1:
The process separates germ removal from concentration steps by introducing microfiltration as a distinct stage. Germs and spores are removed by physical filtration through membranes with specific pore sizes, while the whey proteins remain in the permeate unaffected by thermal denaturation. This segmentation allows independent optimization of each function.
Solution Approach 2:
The microfiltration membrane acts as an intermediary between the milk concentrate and the germ removal process. Instead of using heat as the mediator to destroy germs, the membrane physically separates them based on size, preserving the thermal sensitivity of whey proteins while achieving germ reduction.
2Manufacturing precision
If lower temperature treatment is applied to preserve whey proteins, then the MPI remains above 5, but the bacterial load becomes too high for marketable products
Solution Approach 1:
The process replaces the thermal mechanical system (heat treatment) with a mechanical filtration system (microfiltration). Instead of using thermal energy to eliminate germs, mechanical pressure drives the liquid through membranes that physically trap germs and spores, allowing low-temperature processing that preserves whey proteins.
Solution Approach 2:
Microfiltration membranes with controlled pore sizes (typically 0.1-10 micrometers) are used to selectively retain germs and spores while allowing whey proteins and other milk components to pass through. The porous structure enables size-based separation without thermal damage to sensitive proteins.
3Manufacturing precision
If microfiltration is applied to remove germs, then ultra-high heating is no longer required and MPI is preserved, but additional process steps are introduced
Solution Approach 1:
The microfiltration step is integrated with the existing concentration process. The permeate from microfiltration is directly fed into the evaporator for concentration, and the retentate (containing germs) is discarded. This merging eliminates the need for separate sterilization steps and ultra-high heating, reducing overall process complexity despite adding filtration equipment.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The process effectively reduces bacterial loads while maintaining a high whey protein index, achieving MPI values of at least 2, preferably 5 to 7, and is technically straightforward, resulting in a product with improved nutritional and marketability characteristics.
Implementation Method 1
the skimmed milk thus obtained is subjected to microfiltration
Implementation Method 2
Surprisingly, it was found that the germs can be separated from the milk quantitatively by microfiltration
Implementation Method 3
subjecting the resulting concentrate to a temperature treatment for a period of at least 15 and preferably 15 to 20 seconds at at least 72 and preferably 72 to 80 °C
Implementation Method 4
the permeate thus obtained is pasteurized
Implementation Method 5
the pasteurized permeate thus obtained is reduced to a dry mass of 30 to 50% by weight
Implementation Method 6
The temperature-treated product thus obtained is processed into a dry powder
Data Source
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AI summary
Production (P1) of low-bacteria whole milk powders involves: removing solids from raw milk using known method, and separating cream, followed by subjecting the skim milk to microfiltration, to obtain permeate; pasteurizing the permeate, followed by concentrating, and discarding the retentate; subjecting the cream to ultra-high heat treatment and added to the permeate again before heat treatment; subjecting the concentrate to thermal treatment; and processing the thermally treated product to obtain a dry powder. A process (P1) of the production of low-bacteria whole milk powders having a whey protein nitrogen index (WPNI) of at least 2, involves: (a) removing solids from raw milk using known method, and separating cream; (b) subjecting the skim milk obtained in step (a) to microfiltration, to obtain permeate; (c) pasteurizing the permeate; (d) concentrating the pasteurized permeate to a dry mass of 30-50 wt.%, and discarding the retentate; (e) subjecting the cream separated in step (a) to ultra-high heat treatment and added to the permeate again before heat treatment; (f) subjecting the concentrate to thermal treatment for a period of at least 15 seconds at a temperature of at least 72[deg] C, and (g) processing the thermally treated product to obtain a dry powder. An independent claim is included for a low-bacteria low-heat whole milk powder, obtainable by the process (P1).