Enzymic changes in lambs' liver during storage. I

Abstract

AbstractThe rates of autolytic degradation of the phospholipids, neutral lipids and protein of lambs' liver have been measured during storage at 37°, 15°, 1°, −10° and −20°, and at 15° and 1° after frozen storage at −10° or −20° for 8 or 14 weeks.Chemical changes in the fresh liver proceeded about 13 times faster at 37° than at 15°, and about 3.5 times faster at 15° than at 1°. At −10° and −20° hydrolysis was hardly detectable after storage for 24 weeks. At 15° the onset of measurable autolytic change was delayed for about 2 days, but no lag period was observed when the material had previously been held at −10° or −20°. This activating effect of freezing on the hydrolytic enzymes was much less marked when post‐thawing storage was at 1°.The degradation of the glycerophospholipids results from the simultaneous removal of the two fatty acid residues, followed by breakdown of the water‐soluble phosphate ester moiety to orthophosphate. The fatty ester linkages of the triglycerides were split even more rapidly than those of the phospholipids, indicating the presence of a true lipase in lambs' liver.Fresh liver remained organoleptically acceptable for up to 10 days at 1° or 1–2 days at 15°, times which were not significantly affected by frozen pre‐storage at −10° or −20° for 8 or 14 weeks. No significant deterioration could be detected by tasting tests after storage for up to 25 weeks at −10° or −20°.