Recovery rate of each species per cooking event.

Organic residues are a rich source of biomolecular information on ancient diets. In particular, foodcrusts, charred residues on ceramics, are commonly analysed for their lipid content and to a lesser extent protein in order to identify foods, culinary practices and material culture use in past populations. However, the composition of foodcrusts and the factors behind their formation are not well understood. Here we analyse proteomic data (available via ProteomeXchange with identifier PXD059930) from foodcrusts made using a series of mixtures of protein- (salmon flesh), lipid- (beef fat) and carbohydrate-rich (beetroot) foods to investigate the relationship between the biomolecular composition of the input and the recovered signal using conventional methods applied to archaeological material. Additionally, using 3D modelling we quantify the volume of foodcrust generated by different ingredient combinations The results highlight biases in the data obtained in the analyses of organic residues both in terms of identified resources reflecting the cooked foodstuffs, e.g., an overrepresentation of fish proteins, as well as with regards to the abundance of foodcrust, for example mixtures of only salmon and beef fat resulted in relatively small amounts of foodcrust, and suggest caution in interpreting the composition of residues formed from complex mixtures of foodstuffs.

有机残留物是获取古代饮食相关生物分子信息的丰富资源。其中，陶瓷器表面的焦结残留物（foodcrusts）是常见的分析对象：学界通常通过检测其脂质含量，并在较小程度上分析蛋白质组分，以辨识古代人群的食物种类、烹饪行为及器物使用模式。然而，目前学界对这类焦结残留物的组成及其形成机制仍缺乏充分认知。本研究针对一系列由富含蛋白质（三文鱼肉）、脂质（牛脂）及碳水化合物（甜菜根）的食材混合制备的焦结残留物，获取其蛋白质组学数据（数据已通过标识符PXD059930上传至ProteomeXchange数据库），并采用适用于考古材料的常规分析方法，探究初始食材的生物分子组成与检测所得信号之间的关联。此外，本研究通过三维建模技术，量化了不同食材组合所生成的焦结残留物体积。研究结果揭示了有机残留物分析中存在的两类数据偏差：其一，在反映烹制食材的鉴定结果层面，鱼类蛋白质的检出存在过度富集现象；其二，在焦结残留物的生成量层面，仅由三文鱼肉与牛脂混合制备的样本所产生的焦结残留物相对较少。本研究同时提示，在解读由复杂食材混合形成的残留物组成时需谨慎行事。