Why archaeological starch grains can be preserved?

This paper explores the above question.

Langejans, G. H. J. 2010. Remains of the day-preservation of organic micro-residues on stone tools. Journal of Archaeological Science 37: 971-985.

For your information, the other approaches to starch preservation in the archaeological sites are as the following. They contain some papers on soil science.

• Ashman, M.R., G. Puri. 2002. Essential soil science: a clear and concise introduction to soil science. p.198. Blackwell Science Ltd, Oxford.
• Barton, H. 2009. Starch granule taphonomy: the results of a two year field experiment. terra australis 30: Archaeological ｓcience under a microscope: studies in residue and ancient DNA analysis in Honour of Tom Loy (M. Haslam, G. Robertson, A. Crowther, S. Nugent, L. Kirkwood Eds.), 129-140. University of Queensland Press, Brisbane.
  
• Barton, H., P. Matthews. 2006. Taphonomy. Ancient Starch Research (R. Torrence,　H. Barton eds.), 75-94. Left Coast Press, INC., Walnut Creek.
• Lentfer, C., M. Therin. 2006. Starch assemblages track modern environmental variation. Ancient starch research (R. Torrence, H. Barton Eds.), 146-150. Left Coast Press, INC., Walnut Creek.
• Evers, A.D., D.J. Stevens. 1985. Starch damage. Advances in cereal science and technology (Y. Pomeranz Ed.) VII. 321-349. American Association of Cereal Chemists, St. Paul.
  
• Lu, T. 2003. The survival of starch residue in a subtropical environment. terra australis 19: Phytolith and starch research in the Australian-Pacific-Asian regions: the state of the art. Papers from a conference held at the ANU, August 2001, Canberra, Australia (D. M. Hart, L. A. Wallis Eds.), 119-126. Pandanus Books, Canberra.

The paper by Langejans shows a model of starch grain preservation. I will conduct some experiments using the similar methods as one of my future researches.