Identification of characteristic aroma compounds in blanched garlic through multidimensional analysis and improvement of sensory quality via cysteine-assisted mild blanching

Abstract

The characteristic aroma compounds in blanched garlic were investigated by solid-phase microextraction (SPME) and solvent-assisted flavor evaporation (SAFE) combined with gas chromatography–mass spectrometry/olfactometry (GC–MS/O). SPME effectively extracted highly volatile, weakly polar, and solvent-sensitive compounds like dimethyl disulfide and 5-hydroxymethyl-2-furfural, while SAFE being more apt to enrich sulfur-containing and heterocyclic compounds such as methyl allyl trisulfide and 3-vinyl-1,2-dithiacyclohex-5-ene. Twenty-eight compounds were identified as crucial aroma compounds through odor activity value (OAV), aroma extract dilution analysis (AEDA), and aroma extract concentration analysis (AECA). Diallyl sulfide, nonanal, and thiophenol were identified only by AEDA, whereas methyl(1E)-1-propenyl disulfide and 2,5-dimethylthiophene were exclusive to AECA. Partial least squares regression (PLSR) analysis further revealed that 2-vinyl-4H-1,3-dithiine, 3H-1,2-dithiole, and methyl allyl disulfide were the predominant contributors to garlic aroma, identifying overlooked key aroma compounds by traditional methods. Different sulfur-containing compounds exhibited synergistic or masking effects that collectively shape the aroma profile of blanched garlic. Greening index, allicin, and fracturability were identified as critical indicators for the blanched garlic process by PLSR. Blanching at 75 °C combined with 0.15 % cysteine increased allicin retention by 49.58 % along with effectively inhibiting greening and enhancing crispness.