Olive stone as a sustainable agricultural by-product: Valorization pathways and prospects in food and feed Industries

Abstract

Background: Olive stone (OS) has emerged as a promising by-product with potential applications in food and feed formulations, owing to its unique properties.  Despite growing interest in recent years, research dedicated to the comprehensive evaluation of OS remains limited.

Aim: This review aimed to elucidate the structure, physical and chemical properties of OS, provide an overview of its diverse application areas, and highlight its potential utilization in food and feed formulations through case studies and recent advancements.

Methods: A systematic literature search was conducted using prominent databases, including Google Scholar, Web of Science, PubMed and Scopus, with a focus on studies published in recent years. The search strategy employed keywords such as olive, olive by-products, olive stone composition, valorization areas, use of agricultural wastes in food. Relevant publications in English or Turkish were considered, resulting in a reference list of 97 articles that were critically reviewed and cited.

Results: OSs are a significant by-product generated during the olive oil extraction and pitted table olive production, constituting approximately 18-22% of the olive fruit. OS possesses a lignocellulosic composed primarily of hemicellulose, cellulose and lignin. Although its current predominant use is as fuel due to its high calorific value, OS exhibits potential for diverse applications owing to its rich composition of fat, protein, bioactive phenolic compounds and dietary fiber. Potential valorization pathways include activated carbon production, oil extraction, furfural synthesis, plastic filling material, cosmetic formulations, biosorbents, resin production, and animal nutritional supplementation. Recent studies have increasingly explored the use of OSs as a functional food ingredient, with promising results demonstrating its efficacy as an antioxidant, nutraceutical and thickening agent in food formulations.

Conclusion: This review underscores the multifaceted potential of OS, particularly in food and feed applications. The valorization of OS aligns with sustainable waste management practices and offers innovative opportunities for enhancing food and feed formulations.

Keywords: Olive, olive stone, waste management, waste valorisation, agricultural by-product