Exploring fruit waste macromolecules and their derivatives to produce building blocks and materials

Fruit production is a pivotal sector of the human diet and world economy. Oranges, bananas, and guava stand out as some of the most widely produced fruits either for direct consumption or industrial processing. Consequently, an environmental problem arises from the waste disposal generated throughout these fruits’ life cycle. Seeds, bagasse, leaves, peel, and the fruit itself are the main residues found, all lignocellulosic biomasses composed mainly of cellulose, hemicellulose, and lignin, in addition to pectin as a minor component. Thus, fruit waste biomass has been investigated for obtaining macromolecules and derivatives as building blocks for several value-added applications within the biorefinery/bioenergy field such as xylooligosaccharides, xylan and pectin-based bioplastics, biofuel, biogas, electrochemical sensors, nanocomposites, among others. However, when it comes to lignin from fruit waste, there is an enormous unexplored potential compared to other feedstocks, especially wood and gramineous plants. This review addresses the lignocellulosic composition of orange, banana, and guava fruit waste, pretreatments, and recent applications, to assist and foment future research on waste biomass conversion.