Influence of allicin on quality and volatile compounds of fresh-cut stem lettuce during cold storage

Lettuce (Lactuca sativa L. var. angustana Irish) was cut into slices and treated with water (control), 2 g/l and 10 g/l allicin respectively, followed by cold storage for 6 days (4 °C, >90% relative humidity). Allicin showed a positive effect on color, while it did not influence fresh weight loss and firmness. The contents of ascorbic acid, soluble protein and soluble sugar in lettuce were maintained by allicin, and degradation of chlorophyll was also delayed. Volatile components were analyzed by gas chromatography-mass spectrometry (GC-MS). The content of two main quality contributors, 1-hexanol and hexanal were much higher in allicin treated samples than control, while the generation of some volatiles such as ethanol, 1-butanol and β-elemene that brings negative influence on the fragrance was significantly inhibited. Conclusively, Allicin treatment helped maintain appearance color, nutrition characteristics and volatile aroma compounds preferred by consumers, therefore this technology could be developed for maintaining the quality of minimally processed lettuce.