title: Use of ultrasonic and pepsin treatment in tandem for collagen extraction from meat industry by-products.
abstract: BACKGROUND
  Relatively little attention is paid to collagen-rich cattle short tendons (musculus extensor communis, musculus flexor digitorum, musculus digitorum profundis) as a source of high content and relatively pure collagen, a meat-processing by-product that is used to a minimal extent. Thus, suitable extraction processes from a meat production by-product to gain intact collagen is promising, which thus become interesting from an economic and environmental point of view.
  
  
  RESULTS
  Two extraction methods were compared: a 48 h pepsin treatment using 0.5 mol L⁻¹ acetic acid and an extraction using pepsin treatment after ultrasonic treatment in a 0.5 mol L⁻¹ acetic acid solution (the total ultrasonic and pepsin treatment time was 48 h). The results indicated that the optimal conditions for the extraction of collagen from cattle tendon with the ultrasonic-pepsin tandem method is: 4°C, tendon pre-swollen for 12 h in 0.5 mol L⁻¹ acetic acid, pepsin amount: 50 U mg⁻¹ of sample, ultrasonic-pepsin tandem treatment time for 18 h and 30 h, respectively. Extracted cattle tendon collagen using ultrasonic and pepsin treatment in tandem was characterised by amino acid analysis, SDS-PAGE, FT-IR, solubility and thermal denaturation temperature. The results show that the ultrasonic-pepsin tandem method can effectively improve the efficiency of pepsin extraction of natural collagen without any compromise of the resultant collagen quality.
  
  
  CONCLUSIONS
  This study provides a favourable process to deal with poorly extractable residue by use of ultrasonic and pepsin treatment in tandem. Extracted collagen possesses an intact molecular structure, which is useful and particularly important for its biomedical applications, such as drug delivery systems, wound dressings, and scaffolds.
authors.affiliation: Institute of Animal Science, Guangdong Academy of Agricultural Sciences, Guangzhou, 510640, China; State Key Laboratory of Livestock and Poultry Breeding, Guangzhou, 510640, China; The Key Laboratory of Animal Nutrition and Feed Science (South China) of Ministry of Agriculture, Guangzhou, 510640, China; Guangdong Public Laboratory of Animal Breeding and Nutrition, Guangzhou, 510640, China.
authors.forename: Xue-Guang
authors.initials: XG
authors.lastname: Ran
authors.forename: Ling-Yun
authors.initials: LY
authors.lastname: Wang
mesh_terms: D019342:Acetic Acid; D000596:Amino Acids / Q000032:analysis; D000818:Animals; D002417:Cattle; D003094:Collagen / Q000737:chemistry / Q000302:isolation & purification*; D006801:Humans; D007220:Industrial Waste; D008461:Meat Products; D015394:Molecular Structure; D010434:Pepsin A / Q000378:metabolism*; D013696:Temperature; D013710:Tendons / Q000737:chemistry*; D014465:Ultrasonics / Q000379:methods*
chemical_list: D000596:Amino Acids; D007220:Industrial Waste; D003094:Collagen; D010434:Pepsin A; D019342:Acetic Acid
keywords: collagen; extraction; pepsin; physicochemical properties; ultrasonic treatment