What is β-(beta)-chitin?

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Chitin can form long and strong fibers when chitin molecules align and crystallize. These chitin crystals can form in different ways. In β-chitin, the chitin chains are aligned in a parallel way, i.e. the reducing ends of neighboring chitin chains point into the same direction. This allows less hydrogen bonds to form between the two chains than in an anti-parallel orientation, so that β-chitin crystals are less dense, and β-chitin fibers are less strong than crystals and fibers formed from α-chitin. In nature, β-chitin is rather rare, it occurs e.g. in the endoskeleton of squid and is secreted by some diatom algae. Thus, commercial β-chitin is rare and more expensive than α-chitin. As β-chitin crystals are less dense than α-chitin crystals, de-N-acetylation to form chitosan is easier and the chitosan produced is of particularly high quality and of high molecular weight (i.e., high degree of polymerization).