Food and cuisine. While ZooMS has been extensively applied to enriching zooarchaeological datasets on subsistence practices and the environment, LC-MS/MS–based approaches have yielded insight into ancient foods and culinary practices. Where environmental contexts have enabled good organic preservation, proteins have been extracted and identified from whole foodstuffs to identify their constituents, for example, from food remains found at cemetery sites in the Tarim Basin, China, including whole cheese curds (100–102) and bread (103), and in Egyptian tombs (104), where dry conditions may have slowed biomolecular deterioration. Similarly, artifacts found in frozen and cold contexts also harbor protein preservation that enables a detailed insight into food remains. For example, Colonese et al. (105) identified proteins from wheat from a residue sticking to the surface of a well-preserved wooden box in the Swiss Alps. Proteomic analysis has also been applied to the stomach contents of “Ötzi the Iceman,” in combination with aDNA, reconstructing Ötzi’s “last meal,” revealing evidence of meat and cereals (106).
As well as identifying taxa and particular plant or animal tissues used for food, ancient proteins are also being used to study food processing and culinary techniques, owing to the fact that the proteins differ in the abundance, type, and chemical modifications when subject to different culinary processes. For example, Yang et al. (101) examined preserved remains of putative cheese curds associated with mummified individuals from Bronze Age Xinjiang. After identifying that proteins in the substrate derived from milk, the authors examined one specific protein identified in detail, kappa-casein, which plays a key role in cheese curd formation. Kappa-casein undergoes specific cleavage of the protein chain when subjected to coagulation by the enzyme rennet. The team observed that such a cleavage pattern was absent, suggesting that these cheese curds were not formed as a result of rennet coagulation but were likely created by using acid or microbial-based dairy processing. This example demonstrates the level of insight possible with the analysis of proteins, generating insight into the taxa identified (cow), the specific food product (dairy), and its potential processing technique (acid/microbial coagulation).
Beyond these exceptional examples, dietary analysis using proteomics has been applied to ancient dental calculus to identify food consumption practices directly from past human mouths. Dental calculus is mineralized tooth plaque, also known as dental tartar, which accumulates on teeth during life and is often preserved on skeletal teeth. Ancient proteins derived from dietary sources have been extracted from this reservoir, revealing evidence of a range of consumed foods. While informative on the consumption of particular foodstuffs, it is clear that this approach may not capture the diversity of foods consumed by that individual, and there is a bias toward certain food groups (107). Where this technique has been particularly informative is in exploring past patterns of dairy consumption (108–112). In contrast to other biomolecular approaches to study past dairying, ancient protein analysis is able to identify the taxa consumed, acting as a “zooarchaeology by proxy,” enabling the identification of animal taxa that may have been important in local economies, environments, and cuisines. In addition, this technique enables an exploration of individual dietary patterns that may be tied to other information gained from osteological or archeological analyses, such as indications of status and health.
Ceramics have also been turned to understand food preparation practices. While the analysis of fats, oils, and waxes is typically applied to this ceramic material culture [e.g., (113–116)], the analysis of proteins has the potential to yield further insights into the taxa used, as well as insights into food mixing (116). While some success from extracting proteins from ceramics has been reported (117–120), challenges have arisen in the removal of protein from the silica matrix and protein preservation in this context is not fully understood (7, 121, 122).
Paleoproteomics has also been applied to understanding animal subsistence. For example, Tsutaya et al. (123) examined the rib bones of a neonate dog, revealing the preservation of dog milk proteins and suggesting that food proteins derived from the animal’s stomach contents have the potential to be preserved in adjacent tissues. Investigations of animal foddering strategies have long been examined by stable isotope analysis and other approaches, e.g., (124–126), and with the development of proteomic strategies, this is a likely avenue of future research.
Future work in the analysis of ancient proteins to understand past food use will be in uncovering biases in the entrapment and preservation of food-derived biomolecules in different archeological substrates. For example, Hendy et al. (107) reported that in samples of ancient dental calculus there appears to be a bias toward the detection of milk proteins over other foods. In addition, future work may be in the integration of protein analysis with other biomolecular approaches, such as lipids, to develop a more well-rounded picture of food contributions, as well as the development and adoption of strategies for protein authentication.