Pulsed Electrical Field Liquid Food Preservation Process
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Solution Overview
Problem
Current PEF processes for liquid food preservation struggle to effectively inactivate Gram-positive bacteria and small-sized microorganisms, especially at pH levels above 4.6, and face limitations in scalability and throughput, leading to inefficient microbial inactivation and potential overheating of products.
Innovation Solution
A process involving resistive heating with a continuous flow of liquid products through an apparatus, applying pulses with durations of at least 10 microseconds and electrical field strengths of 0.1 to 5 kV/cm, which maintains the maximum temperature below 92°C, effectively inactivating both Gram-negative and Gram-positive bacteria across a wide pH range without the need for cooling sections.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If conventional PEF treatment with short pulses (2 microseconds) and high electrical field strength (10-20 kV/cm) is used, then treatment time is reduced, but inactivation efficiency against Gram-positive bacteria and small microorganisms deteriorates
Solution Approach 1:
The patent changes the pulse duration parameter from conventional 2 microseconds to at least 10 microseconds, and adjusts electrical field strength to 0.1-5 kV/cm. This parameter transformation enables effective inactivation of Gram-positive bacteria and small microorganisms while maintaining efficient processing speeds, resolving the contradiction between treatment time and inactivation efficiency.
2Reliability
If higher electrical field strength and longer treatment time are applied to improve microbial inactivation, then inactivation effectiveness increases, but product temperature increases excessively
Solution Approach 1:
The patent employs periodic pulsed electrical fields with pulse durations of at least 10 microseconds and intervals between pulses. This periodic action delivers cumulative microbial inactivation效果 while allowing thermal dissipation during intervals, preventing excessive temperature rise and preserving product quality.
Solution Approach 2:
By changing the pulse duration to at least 10 microseconds and electrical field strength to 0.1-5 kV/cm, the patent achieves effective microbial inactivation with lower energy density per pulse, reducing overall heat generation while maintaining treatment effectiveness.
3Temperature
If cooling sections are added to prevent overheating during PEF treatment, then temperature control improves, but device complexity and process length increase
Solution Approach 1:
The patent enables the PEF treatment system to self-regulate temperature through optimized pulse parameters (at least 10 microseconds duration, 0.1-5 kV/cm strength). The system inherently limits temperature rise by controlling energy input, eliminating the need for external cooling sections and reducing device complexity.
4Reliability
If conventional PEF conditions are used for low pH products, then inactivation effectiveness is good, but applicability to higher pH products (above 4.6) is limited
Solution Approach 1:
The patent extends pH applicability by adjusting pulse duration to at least 10 microseconds and electrical field strength to 0.1-5 kV/cm. These parameter changes compensate for reduced PEF effectiveness at higher pH levels, enabling effective treatment of products with pH above 4.6 while maintaining good inactivation results.
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
This approach efficiently reduces microbial loads in liquid products while preserving the quality of the food by maintaining temperatures below critical thresholds, enhancing the preservation of fresh taste and nutritional values, and allowing for higher throughput and broader pH applicability compared to conventional methods.
Implementation Method 1
Pulsed electrical fields (PEF) is used as a technology to induce electroporation of a cell membrane by the application of pulses of a short period of time by an external electrical field of high intensity. The most widely accepted theory for this phenomena is that by application of an external electrical field on a biological membrane, local instabilities in the lipid bilayer are induced, eventually leading to pore formation.
Implementation Method 2
Process for fast and homogeneously heating a liquid product to a predetermined temperature by means of resistive heating
Data Source
AI summary
The present invention relates to a process for fast and homogeneously heating a liquid product to a predetermined temperature by means of resistive heating. According to the invention, sufficient and effective microbial inactivation is achieved upon applying an electrical field strength of between 0.1 - 5.0 kV/cm for a prolonged period of time, thus by selecting a relatively low electrical field strength and a pulse duration of at least 10 microseconds while the maximum temperature of the liquid product autonomously remains below 92°C during the resistive heating. The process of the invention is efficient at neutral pH and at pH below 7. Furthermore, the process of the invention is efficient in inactivating a broad array of relevant micro-organisms. The present invention further relates to said process wherein the liquid product is pre-heated prior to subjecting the liquid product to the process. The present invention also relates to the liquid product obtainable by the process according to the invention.