Glass Formation by Galactopinitol with Other Sugars and Their Ability to Protect Phospholipid Vesicles from Drying Damage

Abstract

A galactopinitol (Galpi), O-α-D-galactopyranosyl-(1→1)-3-O-methyl-D-chiro-inositol, together with sucrose, raffinose, and stachyose were extracted from seeds of Leucaena leucocephala (Lam.) de Wit and characterized for glass formation and phospholipid vesicle stabilization during dehydration. Raffinose, stachyose, and Galpi were found to have good glass forming properties, and their glass transition temperatures (Tgs) were 67.4, 66.4, and 33.40℃, respectively. The Tgs were much higher than those of glucose and sucrose. The Tg for a mass ratio mixture of Galpi and sucrose of 0.3/1 was greater than 0 and was similar to that of the same ratio mixture of raffinose to sucrose, indicating that Galpi as well as oligosaccharides plays an important role in glass formation. The mixture of Galpi plus sucrose appeared to protect phospholipid vesicles during dehydration and rehydration to the same degree as did raffinose or the stachyose plus sucrose mixture. The percent protection (leakage of isocitrate) of vesicles provided by sucrose, Galpi, raffinose, and stachyose was in the approximate range of 38 to 48%. The results suggest that Galpi may prevent cellular collapse during the desiccation of leucaena seeds and function much the same as oligosaccharides.