Submitted to: Journal of American Leather Chemists Association
Publication Type: Peer reviewed journal
Publication Acceptance Date: 9/30/2013
Publication Date: 4/1/2015
Citation: Ramos, M., Muir, Z.E., Trusello, J., Truong, N. 2015. Development of an alternative low salt bovine hide preservation using PEG and crude glycerol, part 1: evaluation of PEG molecular weight fractions. Journal of American Leather Chemists Association. 110(4):109-113. Interpretive Summary: The raw hides consist mainly of protein and water, which makes them vulnerable to microbial attack and decomposition once the hides are taken off the slaughtered animals for their meats. The high moisture content and other nutrients of the raw hide attract and support the growth of microorganisms which can then degrade the protein making the hides unsuitable for the production of good quality leather. The removal or reduction of the hide moisture content is the most important factor to consider when developing an effective hide preservation process. Unfortunately, high salt concentration of about half the weight of the raw hide is required in brining, commonly used preservation process. During tanning, the excess salt has to be removed in order not to interfere with the tanning chemicals and has been the source of a tremendous pollution problem. It is imperative that the hides and leather industry develop alternative environmentally friendly hide preservation that requires lower concentration of salt in order to diminish the environmental impact that the traditional standard salt preservation can introduce. ARS scientists at Wyndmoor, PA have developed an improved preservation process by incorporating a water absorbing agent such as the polymer of polyethylene glycol (PEG). Results showed that only a fraction of the usual salt concentration is necessary to generate environmentally friendly and efficiently preserved hides.
Technical Abstract: Brine curing using sodium chloride is widely used for the short-term preservation of cattle hides. Due to economics and efficiency, it has become the traditional method of hide preservation used by meat packers, hide processors, and tanners worldwide. But brine curing is known to cause serious effluent pollution problems in the environment. The main objective of the current study was to develop an alternative brining process that requires less salt to effectively preserve bovine hides by incorporating dehydrating agents. In low salt preservation, the anticipated hardening effect due to over dehydration caused by polyethylene glycol (PEG) polymers was compensated by adding crude glycerol and sodium carbonate. Low molecular weight PEGs were more effective than high molecular weight polymers. Preservation was found to be effective because no sign of putrefaction was observed in alternatively cured hides, and the properties of these hides were comparable to those of traditionally preserved hides. When PEG was incorporated, the salt concentration required for hide preservation could be reduced.