Evaluation of sources and methods of pectin extraction from fruit and Vegetable wastes: A Systematic Literature Review (SLR)

The potentially commercial sources of pectin are limited. Researchers have studied different extraction methods using a wide variety of fruits and vegetables to obtain pectins with better characteristics. The objective of this work was to identify the methods used in the extraction of pectin, the most used sources and the operation parameters that enable the achievement of higher yields and the final characteristics of the obtained product. These are based on bibliometric methods for exploring the structure of knowledge in this field for the last twelve years. To this end, a Systematic Literature Review (SLR) using the SCOPUS database was carried out, which allowed identifying keywords and formulating search equations to find scientific articles on the topic in question. After selecting the articles, a detailed reading of these works was carried out, and the used extraction methods and the evaluated variables, yields and characteristics were analyzed. This article compares and discusses the effects of conventional and non-conventional pectin extraction techniques, which may provide valuable information on sources and alternatives for pectin extraction to ease decision-making in future research. The acid hydrolysis method remains the most widely used pectin extraction technique since it provides higher yields. It is followed by microwave-assisted extraction, ultrasonic extraction, and the enzymatic method, which have a greater capacity to deliver pectins with high methoxyl content. Finally, non-conventional methods such as radiofrequency, ohmic heating, and aqueous two-phase extraction are presented as promising techniques that offer pectins with a high degree of esterification in addition to good yields.