Emerging technologies to obtain pectin from food processing by-products: A strategy for enhancing resource efficiency

Background: Even though raw and processed crops are consumed as food worldwide, one-third of these agricultural produces go as waste or by-products. These by-products contain several valuable components, such as pectin, that can be valorized in the food processing industry through waste recycling to improve resource efficiency. However, the conventional methods (e.g., acid extraction of pectin) have limitations, such as low yield, and are energy-intensive and associated with environmental problems. Therefore, the possibility of using emerging processing technologies for pectin extraction has attracted wider attention. Scope and approach: This paper aims to describe the status of the valorization of food and agricultural by-products through the application of emerging processing methodologies with specific attention to pectin extraction. In this regard, papers published in this area of research during the past decade were retrieved from scientific databases and their findings were analyzed. Key findings and conclusions: Emerging thermal (e.g., microwave and ohmic heating) and non-thermal (e.g., moderate electric field, pulsed electric field, high-pressure processing, and ultrasound), as well as combinations of these technologies (e.g., a combined effect of microwave and ultrasound) are among the innovative approaches that have been used for pectin extraction. These methodologies can result in higher extraction yields and produce pectin with a desirable degree of esterification. However, the industrial application of these technologies can be challenging at this moment due to relatively high capital costs, limited professional expertise, and inadequate data on process upscaling. Therefore, research on up-scaled versions and further training in this area of food processing are recommended.