Characterization of fragrant compounds in different origins of wheat paste from China

Abstract

Wheat paste, a traditional fermented condiment widely consumed in China, exhibits regional variations in physicochemical and flavor due to differences in raw materials and fermentation methods (natural versus temperature-controlled). In this study, 16 regionally representative wheat paste samples were analyzed using physicochemical measurements, headspace solid-phase microextraction gas chromatography-mass spectrometry, and sensory evaluation. Samples produced via temperature-controlled fermentation in northern China showed higher pH, ammonia nitrogen, and total nitrogen levels, whereas southern samples produced through natural fermentation exhibited greater total acidity. A total of 133 volatile compounds were identified. Temperature-controlled fermentation in northern China facilitated the balanced release of alcohols, esters, and aldehydes, yielding more stable flavor compound profiles. In contrast, southern samples, typically containing higher wheat flour content, had elevated aldehyde levels. Partial least squares discriminant analysis identified 38 substances with VIP >1, including ethanol, ethyl acetate, ethyl caproate, furfural, and phenylacetaldehyde. Combined with sensory evaluation results, these compounds were found to contribute to the regional differences in aroma. Northern samples exhibited different advantages in alcohol, sauce-flavor, caramel-like, smoky, and fruity aromas, while southern samples were primarily distinguished by alcohol, fruity, and smoky aromas. These findings provide a theoretical basis for expanding industrial wheat paste production with different flavors.