Development and optimization of a non-thermal pasteurization technique for liquid dairy beverages using pulsed electric fields (PEF) and assessment of shelf-life and sensory quality.

Project Abstract

This study investigates the development and optimization of a non-thermal pasteurization technique for liquid dairy beverages utilizing pulsed electric fields (PEF) and evaluates shelf-life extension and sensory quality to meet safety, quality, and consumer acceptability criteria. A systematic experimental framework was employed to determine critical PEF parameters including electric field strength, pulse duration, pulse frequency, total treatment time, and temperature control to achieve effective microbial inactivation while preserving heat-sensitive bioactive compounds and organoleptic properties. A factorial design and response surface methodology were used to model the effects of PEF variables on target microorganisms (such as mesophilic bacteria, lactic acid bacteria, yeasts, and spoilage molds) and on quality indicators including viscosity, color, turbidity, aroma compounds, and dairy-specific proteins and fats. Microbial inactivation kinetics revealed that high-intensity, short-duration pulses coupled with precise duty cycles achieved substantial reductions comparable to conventional thermal pasteurization, with significantly reduced thermal load. Optimization analyses identified a PEF operating window that achieved >5-log reductions for common dairy spoilage organisms within safe energy consumption limits, while maintaining lactose integrity, casein micelle stability, and minimal denaturation of whey proteins. The study also assessed shelf-life extension under refrigerated storage (4–7°C) over 28 days, monitoring microbial counts, pH, titratable acidity, lipid oxidation indices, proteolysis markers, and physicochemical stability. Results demonstrated a marked delay in spoilage onset and maintained sensory attributes, including creaminess, mouthfeel, flavor balance, and dairy aroma, in comparison with heat-pasteurized controls and untreated samples. A comprehensive sensory analysis was conducted using a trained panel and consumer testing to evaluate acceptability, detection thresholds for off-flavors, and overall liking. Multivariate analyses integrated physicochemical data with sensory profiles to elucidate correlations between PEF-induced structural changes in milk constituents and perceived quality. Additionally, energy efficiency and process economics were evaluated to determine the feasibility of industrial-scale implementation. The optimized PEF protocol achieved robust microbial safety while preserving essential nutrients such as vitamins, minerals, and bioactive peptides, and maintaining rheological properties consistent with consumer expectations for liquid dairy beverages. This research demonstrates the potential of PEF as a viable non-thermal pasteurization technology for dairy beverages, offering improved energy efficiency, reduced thermal impact on quality, and extended shelf life without compromising sensory appeal. The findings provide practical guidelines for pilot-scale deployment, regulatory compliance, and integration with existing dairy processing lines, highlighting opportunities for product diversification, clean-label positioning, and enhanced consumer trust in minimally processed dairy products. Further work is recommended to validate long-term shelf stability across varying storage conditions and to explore the applicability of the optimized PEF framework to different dairy matrices and fortification schemes.

Project Overview

What This Project Is About

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This project explores a non-thermal method to pasteurize liquid dairy drinks using pulsed electric fields (PEF). It looks at how short, strong electric pulses can inactivate harmful microbes without cooking the drink, and how this process affects taste, texture, and shelf-life.

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The Problem It Addresses

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Many dairy drinks are sensitive to heat, which can change flavor and nutritional value. Traditional pasteurization uses heat and can degrade quality. PEF offers a potential way to safely preserve dairy drinks while keeping fresh taste and nutrients. This project examines if PEF can be a practical alternative on a small or large scale.

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Objectives of the Project

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1. Understand how PEF treatment parameters affect microbial safety in dairy beverages.
2. Evaluate changes in flavor, texture, and appearance after PEF treatment.
3. Identify optimal PEF settings that balance safety and quality.
4. Estimate shelf-life improvements under typical storage conditions.
5. Provide practical guidelines for implementation in dairy processing.

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What You Will Do Step by Step

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1. Review basic concepts of pasteurization and PEF.

2. Prepare dairy beverage samples and apply different PEF settings.

3. Test for safety indicators (microbial counts) and quick quality checks (pH, color).

4. Conduct sensory tests with simple panels to assess taste and mouthfeel.

5. Analyze data to find which settings meet safety and quality goals.

6. Model shelf-life changes under storage scenarios.

7. Compile practical recommendations for industry use.

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Expected Outcome




We expect to identify PEF conditions that reliably inactivate microbes while preserving taste and nutrients, along with a clear view of shelf-life benefits and guidelines for real-world application.