Recent Advances in the Processing of Agri-food By-products by Subcritical Water

The improper disposal of by-products from the agri-food industry raises global economic concerns. Therefore, proper management, development, and optimization of promising technologies like subcritical water processing can improve extraction and hydrolysis from by-products. Subcritical water acts as an acid catalyst, hydrolyzing by-products. Different residues from agri-food chains, such as pomace, peel, husk, seed, and straw have been used to obtain products, such as sugars, amino acids, phenolic compounds, pectin, and others. Furthermore, combining subcritical water with other technologies such as microwave, high-intensity ultrasound, and pulsed electric field can increase process efficiency, and promote sustainable economy. Therefore, this review addresses advances and trends in the role of subcritical water technology in treating by-product from the agri-food industry. By optimizing process variables (temperature, pressure, time, flow rate, and modifiers), hydrolysis and extraction of compounds can be maximized, minimizing degradation. Patents in the last five years have demonstrated the industry interest in subcritical water technology with high application prospects.