Metabolomics for Agricultural Waste Valorization: Shifting Toward a Sustainable Bioeconomy.

Agriculture has been considered as a fundamental industry for human survival since ancient times. Local and traditional agriculture are based on circular sustainability models, which produce practically no waste. However, owing to population growth and current market demands, modern agriculture is based on linear and large-scale production systems, generating tons of organic agricultural waste (OAW), such as rejected or inedible plant tissues (shells, peels, stalks, etc.). Generally, this waste accumulates in landfills and creates negative environmental impacts. The plant kingdom is rich in metabolic diversity, harboring over 200,000 structurally distinct metabolites that are naturally present in plants. Hence, OAW is considered to be a rich source of bioactive compounds, including phenolic compounds and secondary metabolites that exert a wide range of health benefits. Accordingly, OAW can be used as extraction material for the discovery and recovery of novel functional compounds that can be reinserted into the production system. This approach would alleviate the undesired environmental impacts of OAW accumulation in landfills, while providing added value to food, pharmaceutical, cosmetic, and nutraceutical products and introducing a circular economic model in the modern agricultural industry. In this regard, metabolomics-based approaches have gained increasing interest in the agri-food sector for a variety of applications, including the rediscovery of bioactive compounds, owing to advances in analytical instrumentation and data analytics platforms. This mini review summarizes the major aspects regarding the identification of novel bioactive compounds from agricultural waste, focusing on metabolomics as the main tool.

Characterisation of Thai strawberry (Fragaria × ananassa Duch.) cultivars with RAPD markers and metabolite profiling techniques.

Strawberries (Fragaria × ananassa Duch.) are one of the most economically important fruit crops worldwide, several commercially viable cultivars are cultivated in the northern region of Thailand. The morphological characters at the young vegetative seedling stage can be very similar, which has hindered breeding efforts. The present study assesses the ability of random amplification of polymorphic DNA (RAPD) markers and metabolomics techniques to distinguish six strawberry cultivars. Both techniques showed congruent results for the leaf tissue and classified the cultivars into three major clusters. For the most different cultivars, Akihime and Praratchatan No.80, fruits were analysed at eight fruit ripening stages. The data highlighted a broad biological variation at the early ripening stages and less biological variation at the mature stages. Key metabolic differences included the polyphenol profile in Praratchatan No.80 and fatty acid synthesis/oxidation in Akihime. In summary, the RAPD and metabolite data can be used to distinguish strawberry cultivars and elucidate the metabolite composition of each phenotype. This approach to the characterisation of genotypes will benefit future breeding programmes.