(Bulletin of the Niigata Prefectural Museum of History Vol.7, 2006)

History and aims of starch analysis

The analysis of ancient starch from archaeological sites is a relatively new methodology that is not yet well established internationally. In this situation, it is important to proceed cautiously and to maintain a record of how the field develops, and of problems encountered along the way.

Although ancient starch was first reported from a dry Arizona cave site in the 1970s (Bruier 1976), it was not until the late 1980s that a wider search for ancient starch began. A landmark paper by Loy, Spriggs and Wickler (1992) announced the discovery of starch on stone flake tools from a cave site in the Solomon islands, a wet-tropical region where the preservation of organic remains was generally not considered likely. While the greatest surprise for most readers of the paper was the antiquity of the remains (approximately 28,000 years BP), the more important question is how did the starch survive, in that particular context? At the time of this discovery, I was a PhD student at the Australian National University, Canberra, in the same department as Tom Loy and Matthew Spriggs, and contributed some of the modern starch samples that were important for the suggested identification of taro (Colocasia esculenta) and Alocasia sp. (kuazi-imo in Japanese). Although there were uncertainties about how the starch was preserved, and its identification, further studies were not conducted at the same archaeological site. At this point in the history of ancient starch research, it was perhaps more important for other investigators to look for ancient starch, in other archaeological contexts, and this is what happened.

Since the early 1990s, discoveries by many archaeologists around the world have shown that starch can survive in a very wide range of enivronmental contexts, over very long periods of time. Positive reports have come in from all the occupied continents (Figure 1), and include one report from an early Holocene cave site in southern China (L.-D. Tracey Lu, 2005 The exploitation of tuber plants in South China. Programme and abstracts of the IVth International Congress of Ethnobotany (ICEB 2005), 21-26 August 2005, Istanbul, Turkey, p. 35.).

Fig. 1 World distribution of archaeological discoveries of ancient starch, 1976 - 2005. Because of the large scale of this map, not all locations can be shown, but examples are included for all regions where ancient starch has been found.

The rapid emergence of starch analysis as a new methodology with wide application in archaeology, led to the formation of the Ancient Starch Research Group (ASRG), an informal grouping led by Robin Torrence and established at an international workshop hosted by the Australian Museum in Sydney (August 17-21, 1998). The 1992 report from the Solomon Islands no longer appears so surprising, but there are still many basic questions that need to be investigated with regard to ancient starch.

Following the 1998 workshop, and together with Dr Huw Barton, an Australian archaeologist now working on starch remains from the Niah Cave site in Borneo, I have tried to identify the key taphonomic questions that need to be answered before we can say exactly how starch is preserved (Barton et al. 2005 in press). Until the taphonomy of starch can be explained, through experimental research, and through comparisons of starch in natural and cultural contexts, there will be no secure theoretical basis for predicting the full possible range of environments where ancient starch can survive. At present, our predictions are limited to extrapolation from previous positive records of ancient starch, in archaeological contexts. This is not bad in itself, but it means that the search for ancient starch is still a hit-and-miss process.

Another matter that requires more attention is the identification of ancient starch. In almost all archaeological reports, botanical identifications have been made using starch - a biological material - without the same level of rigour or care that would be demanded in the biological sciences. Typically, the archaeological result and identification are presented with a minimum of comparison with modern reference materials, and with insufficient data for complete certainty, but the result is then incorporated into the archaeological literature without serious questioning. More sensitive techniques are needed for recording and comparing ancient and modern starch samples, and this will require greater collaboration with biological science laboratories. In our own work so far, we are not yet sufficiently familiar with ancient and modern materials to make any confident identifications of ancient starch, although certain plants can be definitely excluded as candidate sources for the starch residues that have been found.

Several years ago, when I first visited the Sannai-Maruyama Jomon site in Aomori, I was amazed by the large quanitity of grinding stones excavated from the site and held in storage (Matthews 2000). That visit convinced me that ancient starch research should also be pursued in Japan, because the vast number of grinding stones excavated in this country offer enormous scope for ancient starch analysis and for resolving questions about the use of food plants before and after the emergence of agriculture in Japan. Fortunately, Makoto Sahara, then Director General of the National Museum of Japanese History, Chiba, also became interested in the potential of ancient starch research, and it is through this connection that Yastami Nishida established the present collaboration between the National Museum of Ethnology and the Niigata Prefectural History Museum. For our present research project, another priority is to begin surveying grinding stone collections held in storage throughout Japan, while learning as much as possible about the manner of their excavation and storage. In this way, it will be easier to place detailed analyses - of ancient starch on tools from particular locations, tool assemblages, and time periods - within a larger social and historical context. At the same time, it is necessary for us to give attention to any aspects of archaeological excavation and curation that may affect the interpretation of starch found on previously excavated tools.

References

Barton, H., D. Samuel and P. J. Matthews (2006) Starch Taphonomy. In R. Torrence and H. Barton (eds), Ancient Starch Analysis.

Bruier, P. L. (1976) New clues to stone tool function. American Antiquity 41:478-484

Loy, T., M. Spriggs and S. Wickler (1992) Direct evidence for human use of plants 28,000 years ago: starch residues on stone artefacts from the northern Solomon Islands. Antiquity 66: 898-912.

Matthews, P. J. (2000) The Search for Starch at Sannai-Maruyama. Sannai-Maruyama Jomon File Nos. 51 (pp. 3-5) and 52 (pp. 6-7).