Molecular Size of Garlic Fructooligosaccharides and Fructopolysaccharides by Matrix-Assisted Laser Desorption Ionization Mass Spectrometry

Fructooligosaccharides and fructopolysaccharides were isolated from different cultivars of garlic. The garlic cultivars investigated included organically grown garlic, elephant garlic, garlic grown in California, and garlic from China. Garlic contained a high concentration of oligo- and polyfructosaccharides, ranging from 125 to 235 mg/g, on a wet weight basis. Fructose:glucose ratio in the fructooligo/fructopolysaccharides was about 15:1. The molecular weight distribution of garlic fructooligosaccharides and fructopolysaccharides was investigated by MALDI-MS. Molecular masses of fructans ranged from less than 1000 Da to around 4500 Da, corresponding to DP as high as 38. Differences in sugar size, among cultivars, were observed. Comparison was made with MALDI-MS spectra of fructose, sucrose, and inulin. Molecular masses of commercially available inulin, from Dahlia tubers, ranged from less than 1000 Da to 4000 Da with a peak value of distribution around 2500, corresponding to DP 14. Dahlia tubers contained mostly oligofructose while garlic cloves contained a mixture of oligofructose and polyfructose. We suggest that the health-enhancing properties ascribed to garlic should also include garlic high content of fructooligo/polysaccharides. Keywords: Fructooligo/polysaccharides; garlic; MALDI-MS