Industrial Cannabis sativa (fiber or hemp): Retting, Hemp Cellulose Extraction and Composite Thin Films for Food Packaging

This literature review paper highlights preparation of hemp cellulose based thin films for the food packaging industries. The Industrial Cannabis sativa L. (Hemp) is a short-season crop with many applications which is used as a functional food, fibre, 3D printed building material hempcrete, biochar, bioplastic, paper, textile, biofuel, oil, cosmetics, skincare, animal bedding, ropes, medicine and as a replacement for graphene in supercapacitors. The hemp stalk has two main fibre types: long outer bast fibers and short inner hurd fibres. The outer bast fibres surround the vascular tissue of the hemp stalk. The main macromolecular compound that occurs in bast fibres is cellulose (40 and 80% of dry mass) used for the preparation of composite films for food packaging industries. The extraction of fibers from harvested hemp stems begins with ‘‘retting’’ for an initial weakening of interactions between the fiber bundles and the woody core and surrounding tissue. Cellulose measured at nanoscale is known as nanocellulose.  Nanocellulose are of two types which are cellulose nanocrystals (CNCs) and cellulose nanofibrils (CNFs). Nanocellulose could replace petroleum-based materials due to its promising advantages, including rich sources, biodegradability, excellent mechanical properties, and biocompatibility. Nanocellulose composite films and coatings can extend shelf life and maintain the quality of diverse food products such as fruits, vegetables, and meats, as has already been reported by some relevant studies.