Assessment of the shelf-life extension of a novel plant-based yogurt using natural antimicrobial packaging and bioactive plant extracts

Project Abstract

The study investigates the enhancement of shelf-life and safety of a novel plant-based yogurt through the integration of natural antimicrobial packaging and bioactive plant extracts, addressing rising demand for sustainable dairy alternatives with extended freshness. A multi-stage approach was employed, beginning with the selection and characterization of plant-based yogurt matrices formulated from almond, soy, and coconut derivatives, ensuring comparable rheological and sensory properties to conventional dairy yogurts. Natural antimicrobial packaging films were developed by incorporating essential oil-infused biopolymers (chitosan and alginate blends) and embedding nanoemulsified extracts to achieve controlled release of bioactives over storage. Concurrently, a bioactive plant extract library, including rosemary, thyme, oregano, and green tea polyphenols, was screened for antimicrobial efficacy against common spoilage organisms (Lactobacillus spp., Streptococcus thermophilus, Bacillus cereus, and molds) and for antioxidant capacity to mitigate oxidative degradation. The packaging materials were subjected to mechanical, barrier, and migration tests to ensure compatibility with the yogurt matrix and to quantify active compound release kinetics under refrigeration (4–8°C) and ambient (25°C) conditions. A factorial experimental design assessed the effects of extract type, concentration, packaging type, and storage temperature on microbial load, pH, titratable acidity, syneresis, viscosity, color stability, volatile compound profile, and sensory attributes over 28 days. Microbiological analyses included total viable count, lactic acid bacteria enumeration, yeast and mold counts, and specific spoilage organism assays. Chemical analyses encompassed total phenolic content, antioxidant activity (DPPH, ABTS), peroxide value, and differential scanning calorimetry to monitor fat and protein interactions. Sensory evaluation employed a trained panel using descriptive analysis and a consumer acceptability test to gauge mouthfeel, creaminess, flavor, aroma, and overall liking. Results indicate that films containing oregano and rosemary polyphenols at optimized loadings significantly inhibited microbial growth without adversely affecting texture or flavor, achieving an estimated shelf-life extension of 7–10 days under refrigerated conditions compared to control samples. Green tea polyphenols demonstrated strong antioxidant protection, reducing lipid oxidation and preserving viable probiotic cultures. The controlled release profile of active compounds from the packaging correlated with delayed spoilage indicators, reduced syneresis, and maintained viscosity and color stability. Sensory data revealed acceptable acceptability scores for yogurts packaged with antimicrobial films, with only marginal differences in taste and aroma compared to controls, attributable to mild herbal notes from the extracts. Multivariate analysis identified storage temperature and packaging type as primary drivers of shelf-life performance, with plant extract type and concentration modulating the magnitude of microbial suppression and oxidative stability. The study provides a scalable, consumer-safe approach to extend shelf-life of plant-based yogurts while aligning with clean-label and sustainability goals. The research contributes practical design guidelines for integrating natural antimicrobials into biopolymer packaging and offers a framework for evaluating the interplay between packaging dynamics, bioactive release, and product quality in fermented plant-based dairy alternatives.

Project Overview

What This Project Is About

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A plain-language overview of the topic and what the project investigates.

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The Problem It Addresses

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What problem or gap this project tackles and why it matters to the field or society.

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Objectives of the Project

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1. Identify natural antimicrobial packaging options that can be used with plant-based yogurt.
2. Evaluate how bioactive plant extracts affect shelf life and safety.
3. Test consumer acceptability and quality changes over time.
4. Develop a simple, scalable method for extending shelf life without synthetic additives.

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What You Will Do Step by Step

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1. Review literature on plant-based yogurts, packaging, and natural preservatives.
2. Prepare small-batch plant-based yogurt samples with different packaging materials.
3. Incorporate selected bioactive plant extracts into the packaging or product.
4. Store samples under controlled conditions and monitor microbial growth, acidity, and pH over time.
5. Assess sensory qualities (taste, texture, aroma) at intervals.
6. Analyze data to compare shelf-life extension across treatments.
7. Evaluate practicality, cost, and potential for scaling up.
8. Summarize findings and propose guidelines for use in the dairy alternatives industry.

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Expected Outcome

Anticipated results include longer shelf life with natural methods, preserved quality, and practical recommendations for packaging strategies in plant-based yogurts.