Recent advances in agri-food waste valorisation and nanoencapsulation of bioactive compounds for sustainable development

Agri-food wastes are a rich source of bioactive compounds which has multifaceted applications to human health. While novel extraction techniques are well-suited for thermolabile compounds, traditional methods—such as soxhlet extraction using ethanol—often exhibit superior efficiency in extracting total phenolics. Encapsulation of these bioactive compounds is essential to improve their stability, and assimilation in the human body. While both micro- and nano-encapsulation can preserve bioactive compounds, nano-encapsulation may be a more viable method due to its enhanced characteristics, such as improved solubility, absorption, and controlled release in biological systems. In this review, various extraction techniques are compared, and concluded that integration of certain extraction techniques gives better results. Ultrasound-assisted extraction combined with pulsed electric field-assisted extraction have been applied to grapes, resulting in a 23–32% increase in polyphenol content and a 17.6-fold reduction in energy consumption during processing. Beyond extraction, the review also compares different nanocarriers and evaluates their solubility for specific applications. Techniques such as spray drying, and freeze drying, are frequently applied due to their broad applicability, high encapsulation efficiency, and ability to promote sustained release of bioactive compounds. A comparative study of freeze-drying and spray-drying for the encapsulation of bioactive compounds from ciriguela peel extracts using gum arabic and maltodextrin demonstrated that spray-drying achieved higher encapsulation efficiency (98.83%) than freeze drying. Despite significant advances, nanoencapsulation techniques face limitations due to the lack of toxicological data and regulatory guidelines. Besides, the challenges associated with the scaling –up of these techniques hinder their translation into real-world applications. Nevertheless, the prospective utilisation of nanoencapsulated bioactive compounds derived from agri-food waste holds significant potential to support the achievement of the sustainability development goals.