Taste testing: gustometry deciphered – a scoping review

Purpose To map and synthesize the protocols and methodological approaches used in chemical gustometry with taste solutions, focusing on taste assessment methods, the solutions and substances employed, concentration ranges and units of measurement, and the procedures used to determine taste thresholds. Methods A systematic literature search was conducted in PubMed/MEDLINE, Embase, and Web of Science. Study selection and data extraction were performed independently and in duplicate by two reviewers, with disagreements resolved by a third reviewer. The review followed the PRISMA-ScR guidelines and was prospectively registered on the Open Science Framework. Results Of 6,881 records identified, 10 studies met the eligibility criteria, comprising 722 participants across three clinical contexts (oncology/hematology, diabetes mellitus, and otologic disease). The whole-mouth sip-and-spit method and assessment of detection/recognition thresholds were most frequently used. Substantial heterogeneity in methods, tastants, and concentration units limited comparability across studies. Conclusion Standardization of chemical gustometry protocols remains a challenge given the methodological heterogeneity identified, underscoring the need for greater methodological rigor and consistency in future research to improve reproducibility and cross-study comparability.