Introduction
The paper explores the growing importance of grape seed oil as a valuable byproduct of the wine industry. This highlights the significant increase in global wine production and the accompanying increase in grape pomace waste, which includes seeds, skins, and stems. In particular, grape seeds are rich in bioactive compounds, making them an ideal resource for producing high-value grape seed oil. This study emphasizes the potential of this oil as a natural antioxidant and antimicrobial agent, and reviews its extraction methods, composition, properties, and food applications.
Methodologies
This study utilized a two-pronged approach comprising a bibliometric analysis and narrative review. Bibliometric analysis was conducted using the Scopus database, analyzing articles published from 1990 to 2023. This helped to identify trends in grape seed oil research, with a notable increase in publications over the last 15 years, particularly in Asian countries. The narrative review focused on the literature related to grape seed oil extraction, its properties, and applications, offering a comprehensive synthesis of the available evidence.
Byproduct of Winemaking
Winemaking generates significant solid waste known as grape pomace, which contains grape seeds. These seeds, comprising 38–52% of the dry residue from winemaking, are typically discarded but hold immense potential for value addition. They are rich in bioactive compounds, such as fatty acids, phytosterols, and vitamins, making grape seed oil an attractive byproduct for commercial and nutritional use.
Figure 1. Wine production by country (a,b), global wine production (c,d), and global wine consumption (e,f) according to the OIV in countries of the old-world and new-world (data extracted from the OIV on 25 August 2023).
Grape Seed Oil Extraction Process
Grape seed oil extraction involves several steps, including drying, grinding, and pretreatment, to optimize the yield and quality. Traditional methods, such as pressing, offer solvent-free extraction, but result in lower yields. Advanced methods, such as ultrasound-assisted extraction and supercritical fluid extraction, improve the efficiency and enhance the recovery of bioactive compounds. Pretreatments such as ultrasonic baths, enzyme application, and pulsed electric fields further enhance the extraction process by improving oil quality and yield. Post-extraction techniques such as centrifugation and filtration ensure that the oil is purified and ready for storage or use.
Figure 2. Grape seed drying process (a) and grinding processing into flour (b).
Yield and Composition of Grape Seed Oil
The yield of grape seed oil depends on the extraction method, grape variety, and the processing conditions. Advanced methods, such as supercritical fluid extraction, yield higher quantities of oil while preserving the essential bioactive compounds. The oil primarily consists of triglycerides, with linoleic acid being the dominant fatty acid, followed by oleic and palmitic acids. It is rich in tocopherols, tocotrienols, and phytosterols, which contribute to its antioxidant and cholesterol-lowering properties. The high polyunsaturated fatty acid content of oil makes it prone to oxidation, necessitating careful storage to maintain its quality.
Figure 3. Grape seed oil extraction process stages.
Applications in Food Products
Grape seed oil has diverse applications in the food industry, owing to its functional properties. It is used in emulsions, meat products, dairy beverages, and chocolates, and its antioxidant and antimicrobial effects enhance the quality and shelf life of food. Innovative uses, such as inclusion in novel formulations, are driven by consumer demand for natural and sustainable ingredients. The odorless nature of oils and their compatibility with various food matrices have further expanded their applications.
Figure 4. Main compounds of grape seed oil.
Future Directions
This study highlights the need for further research and innovation to fully utilize grape seed oil. Optimizing extraction methods, exploring new applications, and integrating sustainability into production processes are the key areas for future exploration. Countries with high wine production could significantly benefit from increased research funding to turn grape seed oil into a commercially valuable resource, reduce waste, and promote sustainability.
Conclusion
The paper concludes that grape seed oil is a promising byproduct of the wine industry with significant nutritional and economic potential. By advancing extraction techniques and expanding their applications, oil can contribute to sustainability and innovation in the food industry. Further interdisciplinary research and investment are required to unlock its full potential and address the challenges of waste management in winemaking.
Read all at: Laqui-Estaña, J.; Obreque-Slier, E.; García-Nauto, N.; Saldaña, E. Advances in Grape Seed Oil Extraction Techniques and Their Applications in Food Products: A Comprehensive Review and Bibliometric Analysis. Foods 2024, 13, 3561. https://doi.org/10.3390/foods13223561