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Analytical techniques for differentiating huacaya and suri alpaca fibers

by Shim, Sohie

Abstract (Summary)
The alpaca industry is burgeoning in North America. The two breeds of alpacas, i.e. huacaya and suri, are very different in appearance despite the close genetic relationship. The most apparent difference is in the crimp characteristics of the fibers in these animals. Because ortho- and para-cortical cell structure is believed to be associated with crimp in sheep’s wool, differential scanning calorimetry (DSC) and scanning electron microscopy (SEM) were used for the investigation of the cortical cell structure of alpaca fibers. Energy dispersive spectrometry (EDS) and IR spectroscopy were also conducted to elucidate the sulfur distribution, cystine oxidation content and á-helical content related to the cortical cell compositions. DSC results determined that huacaya have an ortho and para bicortical structure whereas suri fibers mostly consist of paracortical cells. Similar results were observed in SEM imaging experiments with plasma etched fiber cross-sections. SEM images illustrate that huacaya fibers have smaller cortical cells assigned to the orthocortex, and larger cortical cells to the paracortex. Localization of cortical cells was observed in huacaya fibers. However, suri fibers only show randomly mixed cells that are likely to be paracortex. The composition of bicomponent cortical cells obtained using DSC or the cortical cell size distribution observed by SEM can be used for discrimination of huacaya and suri fibers. Sulfur analysis performed by EDS was unable to discriminate huacaya and suri fibers readily. The use of Igor Pro software enhanced the presentation of sulfur distribution by means of a three dimensional rotation. IR spectra of huacaya and suri fibers distinguish neither cystine oxidation content nor helical structures.
Bibliographical Information:

Advisor:

School:The Ohio State University

School Location:USA - Ohio

Source Type:Master's Thesis

Keywords:dsc scanning electron microscopy eds ir spectroscopy alpaca fibers cortical cells

ISBN:

Date of Publication:01/01/2003

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