Morphology and Physicochemical Properties of 3 Lilium Bulb Starches

Lilium (Liliaceae) is an important wild plant and is used as food and traditional medicine worldwide. One Lilium cultivar (Lilium lancifolium) and 2 wild types (Lilium leucanthum and Lilium rosthornii) that are commonly distributed in Western China were investigated to completely utilize Lilium resources. The morphology of the flowers, bulbs, and scales and soluble sugar, total starch and amylose contents was remarkably different among the 3 Lilium species. Starches from the 3 Lilium species presented different granule size and shape. The starch of L. lancifolium exhibited higher swelling power and solubility than that of L. leucanthum and L. rosthornii. The starches from the 3 Lilium bulbs presented similar X-ray diffraction patterns and Fourier transform infrared spectroscopy. Among the 3 Lilium species, L. lancifolium showed the lowest crystallinity and the largest proportion of ordered structures in granule external region. Gelatinization temperatures and retrogradation percentage were significantly lower, but gelatinization enthalpy was significantly higher in L. lancifolium than those in L. leucanthum and L. rosthornii. Pasting properties of starch were different among the 3 Lilium species. Starch from L. lancifolium showed the highest degree of amylopectin branching, followed by L. leucanthum and L. rosthornii. Starches from L. leucanthum and L. rosthornii showed higher resistance to porcine pancreatic α-amylase hydrolysis compared to that of L. lancifolium. These results indicated that 3 Lilium bulbs exhibited remarkable differences in morphological, crystal, thermal, pasting, and hydrolysis properties of starches.