Chitosan and its applications in oenology

This paper reviews the main applications of the biopolymer chitosan, the main derivative of chitin, a material usually obtained from natural sources accessible at low cost, i.e., industrial wastes from fisheries. Due to its natural origin, which confers biodegradability and biocompatibility properties, in addition to its low toxicity, chitosan has been gaining attention in numerous sectors, such as agriculture, food, medicine, pharmaceuticals, etc., including also important oenological applications due to its potential as a green alternative to the use of sulphite. Among the many applications that can be generated from these materials in the wine-making area, their use has been reported for the clarification of must; in the preparation of films for the removal of contaminants, whether organics such as ochratoxin A or inorganics such as some metal ions and their salts; the control of turbidity caused by protein precipitation; the encapsulation of yeasts of oenological interest and enzymes for the control of adverse microorganisms such as Brettanomyces; the manufacture of sensors and nanosensors for the quantification of contaminants, the quality control of starting materials and final products, the optimisation of fermentation processes, the monitoring of storage conditions, etc. As a result of this review, significant development of the applications of this material in the oenological area can be expected, especially due to the possibilities of preparing new derivatives, including the great variety of these that have been recently proposed through click reactions, as well as the growing incursion of chitosan in nanobiotechnology.