Characteristics of fructan∶ fructan 1-fructosyltransferase in garlic

Fructans account for the majority of dry weight of garlic bulbs, which possess various health benefits.Characteristics of fructan: fructan 1-fructosyltransferase ( 1-FFT) in garlic was investigated to illustrate the changes of fructans in garlic during storage and processing.The results showed that only 1, 1-Kestotetraose was produced by 1-FFT when 1-Kestose was used as the substrate.1-FFT mainly existed in the 40% ~50% ammonium sulfate fraction.The optimum p H of 1-FFT was 6.0, 1-FFT was stable in a range of p H 5.5~6.5 for 1 h.The optimum temperature was 25 ℃, 1-FFT was stable at 15~25 ℃ for 1 h.1-FFT was activated by low concentration of Mn²⁺, Mg²⁺and Fe³⁺, inhibited by Cu²⁺, Zn²⁺and Ag⁺.Enzymatic activity was increased with the ascending concentration of substrate, and Kmwas 0.6977 mol/L, Vmaxwas 116.23 μg/h. Enzymatic activity of 1-FFT was affected by temperature, p H, various metal ions and substrate concentration, regulating those influence factors could regulate the metabolism of garlic fructan and prolong the storage of fresh garlic.