Tissue-specific safranal accumulation in Gardenia jasminoides fruits: A potential source of a GRAS flavor compound from processing by-products

iAbstract Safranal, a GRAS-approved flavor compound with antioxidant and anti-inflammatory activities, is sourced almost exclusively from Crocus sativus stigmas at prohibitively high cost. Gardenia jasminoides , a medicine and food homology plant, has been proposed as an alternative, but whether its fruits naturally accumulate safranal remains controversial. Here, we quantified safranal in four fruit tissues (green pericarp, green sarcocarp, red pericarp, red sarcocarp) at two ripening stages using HS-SPME-GC-MS and LC-MS/MS, and characterized the expression of 14 core biosynthetic genes by qRT-PCR. Safranal was detected in all tissues, peaking in red sarcocarp (38.17 ng/g FW), followed by red pericarp (24.00 ng/g FW), green sarcocarp (1.40 ng/g FW), and green pericarp (0.28 ng/g FW). Although the levels are lower than those in C. sativus stigmas, the high fruit biomass and established cultivation of G. jasminoides warrant further investigation into whether its processing residues can serve as an alternative source of this GRAS flavor compound. Carotenogenic genes ( GjPSY , GjPDS , GjZDS , GjLCYB , GjBCH ) were predominantly upregulated in red pericarp, consistent with zeaxanthin accumulation. GjCCD2 was green-pericarp-specific, whereas GjCCD4a dominated in red tissues; six GjUGT709G1 paralogs showed divergent tissue- and stage-dependent expression. Together, GjCCD2 , GjCCD4a , and GjUGT709G1 paralogs represent candidates potentially contributing to safranal production in G. jasminoides fruits. These findings provide the first systematic evidence that safranal naturally accumulates in G. jasminoides fruits in a tissue-specific manner associated with transcriptional regulation. This work provides a molecular foundation for breeding and metabolic engineering strategies aimed at enhancing safranal yield in G. jasminoides .