Variability in S-Alk(en)yl-l-Cysteine Sulfoxides in Garlic within a Seven-Month Period Determined by a Liquid Chromatography - Tandem Mass Spectrometry Method

The composition of garlic (Allium sativum L.) may vary among cultivars and, moreover, change over time, thereby affecting both biological activity and flavour. Thus, it is important to identify the trends in the content of bioactive compounds in garlic, by reliable analytical methods. This study was focused on the key sulfur-containing compounds, S-alk(en)yl-l-cysteine sulfoxides (alliin, isoalliin, methiin, propiin), which were quantified by a fast liquid chromatography - tandem mass spectrometry (LC-MS/MS) method. Several garlic cultivars were monitored repeatedly within seven months: one month before harvest maturity; at harvest maturity; and after two and six months of storage. The results showed not only a high variability among individual cultivars, but also among samples of the same cultivar grown at different localities. During storage, a significant increase in isoalliin content (up to 54-fold after six months) occurred. Nevertheless, none of the cultivars showed significantly different properties compared to others, suggesting that many other factors affect garlic composition.