Olfactory-gustatory cross-modal integration: mechanisms of aroma-induced sweetness enhancement, sensory evaluation methodologies, neuroimaging evidence and advances in influencing factors.

backgroundExcessive sugar intake induces health issues such as excess energy, obesity and cardiovascular diseases. Reducing sugar consumption has become a global consensus; however, achieving this without compromising flavour perception remains a major challenge. Previous studies have highlighted the potential risks associated with non-nutritive sweeteners, and novel measures for sugar reduction, such as modifying sweetener ratios and enzymatic conversion, are limited in scope. In-depth studies have revealed that aroma-induced sweetness enhancement is a promising alternative for reducing sugar consumption without compromising perceived sweetness, enabling a healthy way of enjoying sweet flavours. AIM OF REVIEW: By systematically sorting out current knowledge on the mechanism of action, evaluation approaches, and influencing factors of aroma-induced sweetness enhancement, and revealing the cross-modal interaction mechanism between aroma and taste, this study aims to provide a theoretical framework for advancing research on multisensory flavor perception. Furthermore, it underscores the potential of the interdisciplinary integration of neurosensory science and food science to inform the design of flavor optimization strategies for low-sugar products, thereby contributing to healthier dietary solutions for targeted populations. KEY SCIENTIFIC CONCEPTS OF REVIEW: Herein, the physiological basis of taste and smell and their perceptual pathways are systematically reviewed, and the neural and psychological factors of olfactory-gustatory synergy are investigated. In addition, this review summarises the sensory evaluation methods and neuroimaging techniques to assess the sweetening effects of aroma. Moreover, it discusses various factors influencing aroma-induced sweetness enhancement, including the physical properties of food, eating environment, individual differences in consumers and oral processing. Aroma-based sweetening has great potential for sugar reduction without compromising sweetness, and future in-depth research requires interdisciplinary cooperation covering multiple dimensions such as molecular mechanisms, personalisation techniques, ingredient screening, stability optimisation, evaluation method innovation and health regulation adaptation.