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Starch analysis
Starch analysis
What is it and what can it tell us?
Starch granules are found in most fruits, roots, tubers, seeds and corms- created by photosynthesis and stored as reserve energy in cells. Ancient starch analysis is a relatively new technique, and the benefits of its usage have only been recognised in last 20 years or so. Starch can provide information upon: vegetation histories or palaeoenvironmental reconstruction; mobility patterns by tracing the movement of crops throughout cultural landscapes; plant domestication as it can be used in conjunction with macrobotanical evidence and also genetics; diet and subsistence; and artefact function through residues found on tools.
What is the best way to collect a sample for analysis?
Depending on the research questions being asked, sampling strategies can involve either targeted spot samples from archaeological features such as storage pits, or bulk samples of no more than 300g taken from archaeological deposits such as midden deposits or other occupation layers. Piha Archaeobotanical Services can advise on the most appropriate sampling strategy.
How can it be extracted?
Piha Archaeobotanical Services have developed an effective methodology for extracting starch from soil samples and residues on artefacts using standard archaeobotanical laboratory protocols.
How can it be identified to species, genus or family?
Starch identification at species level is through a comparison of characteristics, or attributes, within the various sizes and shapes depending upon the original location of the starch granule in the plant. This is because starch granule morphology is genetically controlled. Some of the major diagnostic attributes include the presence/ absence of lamellae or growth rings and vacuoles, the position of the hilum, faceting and fissuring, along with length, width and shape.
What types of samples can I send for analysis?
Soil samples or artefacts from archaeological deposits.
What is the cost of analysis?
$300/ soil sample or $200/ artefact for starch extraction and analysis of up to 100 grains (including tabulation and reporting of results).
What will Piha Archaeobotanical Services provide?
What will Piha Archaeobotanical Services provide?
Tables detailing the presence of starch granules and identification of these for each sample, as well as a summary interpreting this data that can be directly inserted into reports based on information provided about the sites and deposits. Due to the many taphonomic processes that affect starch preservation, the quantification of starch is not usually a reliable dataset and will not be provided unless requested. If required, images can also be added for publication.
Example of table showing presence/absence results of starch analysis from Talasiu, a late-Lapita site in Tonga dated to 2750-2650 cal BP (Ussher, E. 2015. Agricultural Development in Tongan Prehistory: An Archaeobotanical perspective. Unpublished PhD Thesis (ANU)).
Example of table showing presence/absence results of starch analysis from Leka, a Formative Period site in Tonga dated to 1300-1000 cal BP, cal BP (Ussher, E. 2015. Agricultural Development in Tongan Prehistory: An Archaeobotanical perspective. Unpublished PhD Thesis (ANU)).
Example of starch extracted from showing presence/absence results of starch analysis from three sites on Tongatapu, Tonga (Ussher, E. 2015. Agricultural Development in Tongan Prehistory: An Archaeobotanical perspective. Unpublished PhD Thesis (ANU)).
SEM imagery of starch from Kūmara/ Sweet Potato (Ipomoea batatas) from the comparative collection held by Piha Archaeobotanical Services.
SEM imagery of starch from Purple yam (Dioscorea alata) from the comparative collection held by Piha Archaeobotanical Services.
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