Application of Grape Pomace as a Natural Food Preservative and Source of Biofuel

Table of Contents

1. INTRODUCTION

1.1 Grape pomace

1.2 Polyphenols

1.3 Yoghurt

1.4 Biofuel

2. EXPERIMENTAL (PART I)

2.1 Samples

2.2 Extraction of phenolic compounds from samples

2.3 Determination of total polyphenols

2.4 Determination of total anthocyanins

2.5 Concentration of extracts with rotoevaporation

2.6 Application of phenolic dry extracts in milk during fermentation

2.7 Application of phenolic dry extracts after fermentation i.e. in yoghurt

2.8 pH – Measurement of the new yoghurt

3. RESULTS (PART I)

3.1 Spectrophotometric analysis

3.2 pH variation of the obtained yoghurt

3.3 Sensory analysis of the new product

3.4 Microbiological analysis of the new yoghurt products

4. EXPERIMENTAL (PART II)

4.1. Production of biodiesel from grape winery waste and fruit peels

5. RESULTS (PART II)

6. DISCUSSION

7. CONCLUSION

8. REFERENCES

Research Objectives and Core Themes

The research investigates the sustainable utilization of grape pomace, a winemaking waste product, for two primary applications: as a natural source of antioxidants to enrich yoghurt and as a renewable feedstock for biodiesel production. The central research question explores whether these waste materials can effectively improve the nutritional profile and shelf-life of dairy products while simultaneously providing a cost-effective, environmentally friendly alternative to fossil fuels.

• Extraction and analysis of phenolic compounds from different grape pomace varieties and berries.
• Development of novel yoghurt products enriched with antioxidants to evaluate pH stability and organoleptic properties.
• Assessment of the antioxidant potential and microbiological safety of the modified yoghurt samples.
• Evaluation of various organic solvents for oil extraction from grape seeds and peels for biodiesel synthesis.
• Comparison of extraction yields and fuel potential of different pomace-derived oils.

Excerpt from the Book

Summary of Chapters

1. INTRODUCTION: Provides an overview of the wine industry waste in Macedonia and the potential of grape pomace as a functional resource for antioxidants and biofuels.

2. EXPERIMENTAL (PART I): Details the methodological approach for extracting polyphenols from six samples and the experimental procedures for creating and testing antioxidant-enriched yoghurts.

3. RESULTS (PART I): Presents the spectrophotometric data, pH monitoring during storage, sensory evaluations, and microbiological testing results for the new yoghurt formulations.

4. EXPERIMENTAL (PART II): Describes the chemical procedures for oil extraction from seeds and fruit peels, followed by transesterification to produce and test biodiesel.

5. RESULTS (PART II): Summarizes the experimental yields of oil and impure biodiesel obtained using different organic solvents across various samples.

6. DISCUSSION: Interprets the findings regarding the impact of polyphenols on yoghurt preservation and evaluates the feasibility of converting winemaking waste into biodiesel.

7. CONCLUSION: Synthesizes the project outcomes, confirming the viability of using grape pomace to enhance food quality and produce sustainable fuel, while suggesting future research directions.

8. REFERENCES: Lists the academic literature and technical resources consulted throughout the study.

Keywords

Grape pomace, Winemaking waste, Polyphenols, Antioxidants, Yoghurt, Fermentation, Biodiesel, Transesterification, Renewable energy, Food preservation, Functional foods, Phenolic content, Anthocyanins, Sustainable development, Waste management.

Frequently Asked Questions

What is the primary scope of this research?

This research evaluates the dual-purpose utilization of grape pomace—a significant winemaking byproduct—specifically for enriching yoghurt with natural antioxidants and as a feedstock for producing renewable biodiesel.

What are the main research themes?

The core themes include sustainable waste management, food science and nutritional enhancement, and the chemistry of renewable energy production from agricultural byproducts.

What is the central research question?

The study asks whether winemaking waste (grape pomace) can be repurposed into value-added products, such as stable functional yoghurts and sustainable biofuels, to mitigate environmental impact and resolve energy scarcity.

Which scientific methodologies were employed?

The study used liquid-liquid extraction for polyphenols, the Folin-Ciocalteu method for quantification, spectrophotometry, pH monitoring of fermentation processes, sensory analysis, microbiological safety testing, and transesterification for biodiesel synthesis.

What does the main body of the work cover?

It covers the extraction of compounds, the creation and storage testing of antioxidant-enriched yoghurts, the oil extraction from seeds/peels, and the experimental conversion of these oils into biodiesel using different solvent configurations.

Which keywords best characterize this work?

Key terms include grape pomace, antioxidants, functional yoghurt, biofuel, transesterification, and waste recycling.

How did the addition of polyphenols affect the yoghurt?

The addition of polyphenols was found to improve the pH stability of the yoghurt during storage and did not negatively impact the creamy texture or taste, while protecting against spoilage.

What were the findings regarding biodiesel production?

The study found that acetic acid was an effective solvent for oil extraction, and that grape seeds and fruit peels are viable, cost-effective sources for biodiesel, demonstrating high potential for future sustainable energy applications.