*New Sources of Pectin: Extraction, Processing, and Industrial Applications DOI: http://dx.doi.org/10.5772/intechopen.109579*

type of acid used influences the extraction conditions and the properties of the pectin obtained [30]. Subsequently, a heat treatment is carried out using a conventional hot plate, or, for more efficient extraction, it can be assisted by microwaves [49] or




#### **Table 2.**

*Unconventional sources of pectins: Hulls or husks and seeds.*

by high-power ultrasound [61]. Finally, separation is carried out using the ethanol solvent, and the pectin obtained is dried.

Among the properties shared by pectins obtained from hulls or husks and seeds is that they are primarily LM pectins, with very varied DEs, and they also can form gels in the presence of ions such as calcium, sodium, or potassium [28]. However, the esterification degree influences the properties of the gels formed [49]. Besides, this type of pectin regularly achieves the formation of stable emulsions [24, 62], a shear-thinning rheological behavior and can even, in some cases, present antioxidant activity [14, 54, 63].

One of the main disadvantages of obtaining pectin from hulls or husks and seeds is its low yield (regularly less than 15%), since the extraction is carried out by conventional methods, where conditions such as the type of acid influence the yield obtained. However, research is currently being carried out on new methods that allow a more efficient extraction and higher yield to encourage the use of unconventional sources of pectin.
