Collagen waste as secondary industrial raw material

Abstract

Use of collagen in food production is limited by its low nutritive value and deficient essential amino acids. Irrespective of gelatine and glue manufactured by boiling refined native collagen, industrial processing of collagen is connected with production of a considerable amount of difficultly utilizable protein waste. In the phase of refining collagen raw material, hydrolysates of keratin and accompanying proteins (albumins, globulins) that are isolated with ease go away; their following usage comes up against similar problems as with keratin. Use of collagen waste as of secondary industrial raw material is usually complicated by an excessive density of irreversible crosslinks introduced for stabilizing against chemical and microbial effects. The first stage in processing such waste is hydrolysis that is partially alkaline, acid, but above all enzymatic, and interesting for its low energy demands. Obtained collagen hydrolysates behave like gelatine, however, with a view to their molecular weight being 5-10 times lower, they exhibit higher hydrophility and formation of their gels requires higher dry substance concentration. Sole collagen hydrolysates proved themselves well as a component in urea-formaldehyde resins reducing formaldehyde emissions by their cured films.The same as polyamides, they form considerably stable networks when crosslinking epoxide oligomers; their potential disintegration through microbial procedures is advantageous when removing protective films prior to recycling plastic automobile or aircraft parts on termination of their life. Collagen hydrolysate, crosslinked with polymeric dialdehydes (e.g. dialdehyde starch) results in biodegradable or even edible packaging materials which, under suitable conditions, may be processed by technology of dipping, casting and drying as well as by procedures typical for processing synthetic polymers (extrusion and compression molding). © 2009 by Nova Science Publishers, Inc.