A mixed aqueous solution of xyloglucan (XG) and locust bean gum (LBG) forms a gel when subjected to freeze-thaw cycles. While LBG alone also forms a gel after freeze-thaw treatment, mixing it with XG produces a synergistic effect, suggesting an interaction between XG and LBG. This effect has been applied in maintaining ice cream shape, and elucidating its mechanism is not elucidated yet. This study reports results using tamarind seed gum (TSG) as XG, observing gelation behavior under freeze-thaw cycles, and structurally investigating the mechanism using scanning electron microscopy (SEM) and small-angle X-ray scattering (SAXS).

TSG and LBG samples were obtained from MP Gokyo Food & Chemical Co., Ltd. SAXS measurements were performed at BL-6A of the High Energy Accelerator Research Organization (KEK).

Melting tests of frozen desserts containing XG and LBG mixtures revealed synergistic effects compared to other polysaccharides. Similar synergistic gelation effects were observed in XG and LBG mixed aqueous solutions. SEM examination of freeze-dried gels revealed a mesh-like structure. Increasing the number of freeze-thaw cycles reduced the mesh size. SAXS measurements also showed increased scattering intensity with more freeze-thaw cycles, indicating enhanced cross-linking regions.