Formation of different flavor characteristics of raw- and boiled-dried oysters

The release of flavor compounds in dried oysters, particularly umami amino acids, is highly dependent on the proteolytic degradation efficiency of specific targeted proteins, which is critically influenced by processing techniques. However, systematic studies on this mechanism remain scarce. This study elucidated how processing techniques govern flavor formation in dried oysters. Mild drying 50 °C in raw oysters triggered intense protein degradation, increasing glutamic acid and maximizing umami intensity, but accumulated bitter compounds. Conversely, 90 °C drying suppressed bitterness yet reduced umami and caused extreme yellowing. Mass spectrometry revealed that hydrophilic domains in ∼35 kDa oyster proteins (mainly glutamic acid-rich proteins, such as β-tubulin chain and actin-like proteins) were enzymatically targeted, releasing free glutamic acid as the core umami contributor. This work demonstrated the synergistic effects of pre-cooking and temperature on flavor, and findings provide a scientific basis for optimizing dried oyster processing.