Possible leafy vegetables in prehistoric southern Vietnamese cuisine with a distinctive biomolecular profile

This paper presents the results of organic residue analysis conducted on eight sampled pottery vessels recovered from one Neolithic site (An Sơn), one Neolithic-Metal Age site (Lò Gạch), and one Metal Age site (Gò Ô Chùa) in Long An, Southern Vietnam. The results indicate a specific combination of terrestrial and aquatic plant sources utilized as leafy vegetables in the culinary practices of the people inhabiting the Mekong River Delta in later prehistory based on their common and distinctive biomolecular profiles. We identified a series of mid-to-long-chain fatty acids, alkanes, and alcohols, as well as a wax ester (tetracosanyl palmitate, C40). To our knowledge, this distinct lipid profile with the prominence of tetracosanol (C24-OH) and hexacosanol (C26-OH), along with C40 wax ester, has not been reported to date in archaeological pottery samples. The detection of these plant waxes provides novel molecular evidence for the exploitation of terrestrial and aquatic plants as leafy vegetables. It also provides archaeobotanical evidence for possible continuity of culinary practice from the Neolithic to Metal Age that involves the usage of pottery for preparing and serving a common and specific combination of plant food sources that are available within the vicinities of the three inland sites of An Sơn, Lò Gạch, and Gò Ô Chùa. These findings highlight the importance of plant food sources in the culinary practices along the prehistoric Mekong Delta.