Evaluation of extraction techniques for chia seed mucilage; A review on the structural composition, physicochemical properties and applications

Plant polysaccharides such as mucilage obtained from seeds, roots, branches, and leaves have gained significant interest in the food and pharmaceutical industries due to their rich chemical, functional and biological properties. Chia seeds which are rich in fiber, proteins, polyunsaturated fatty acids, and minerals are capable of producing mucilage upon hydration in water. The process of obtaining chia mucilage is rather simple involving three different stages, namely; hydration, extraction, and recovery. However, in conventional treatment, incomplete removal or detachment of the mucilage from chia seeds occurs, which tends to reduce its yield, and thus hinders its application. In addition, extraction parameters such as time, temperature, and water-to-seed ratio affect the yield and quality of chia mucilage. Alternative and emerging extraction technologies have been reported to produce mucilage with tailored properties. As such, this review discusses different emerging extraction technologies of obtaining chia mucilage, mainly ultrasound-assisted and microwave-assisted extraction, and their influence on the yield and functional properties of chia mucilage. This poses a greater diversity of applications of chia mucilage including fat/egg replacers, gluten-free products, carrier-based systems (micro- and nanoparticles, coatings, and edible films), and stabilizers. Although, many studies have been reported on its applications, nevertheless, studies related to improving the sensory profile of these products as well as information regarding their safety are important to attract consumers.