The differential survival of native starch during cooking and implications for archaeological analyses: a review

Cooking makes foods more palatable and digestible, less toxic and suitable for longer-term storage. Starch granules usually undergo gelatinisation during cooking, resulting in the loss of native structure and morphology. Once fully gelatinised, starch is very difficult to recognise microscopically and to classify taxonomically, impeding identification of cooked starch in archaeological food residues. Gelatinisation involves a complex interplay between temperature, moisture content and the presence of solutes, lipids and proteins, as well as species-specific starch physicochemical properties. Understanding the influence of these factors, particularly moisture, on the degree and extent of starch conversion during heat treatment enables predictive models of native starch survival in archaeological samples based on cooking method and food type. The findings of this review indicate that differential native starch survival may significantly influence archaeobotanical reconstructions and interpretations of artefact function.