Dead Sea Scroll parchments: unfolding of the collagen molecules and racemization of aspartic acid

Abstract

The parchments of the Dead Sea Scrolls were prepared from the skins of animals, mainly sheep and goats^1,2. They were copied and hidden between the beginning of the first century BC and AD 70³. Since then and until their discovery in the late 1940s by local Bedouins, they were located in caves close to the northwestern shore of the Dead Sea⁴. Having been handled by various intermediaries for periods of up to 8 yr, most of the intact scrolls are housed in the Israel Museum, Jerusalem. We have examined small pieces (≲25 mm²) from these scrolls, together with random fragments without any writing, to study some of the chemical changes which have occurred in the past 2,000 yr or so. Using X-ray diffraction and racemization analyses, we found that a major degradative change is due to the unfolding of the collagen molecules to form gelatin and that the degradation generally occurred many centuries ago.