1074Enhancement of the solubility of poorly soluble compounds by low-molecular-weight tamarind seed polysaccharide

Tanaka M.1**, Baba Y.2, Ueda Y.1 , Kittaka M.1, Iwabuchi T.2, Fujimura A.1 , Yabuta T.1, Suzuki Y.2, Yamatoya K.2 , Tsuruha Y.2, Kitamura S.1

1Sanwa Starch Co., LTd. Kashihara, Nara, Japa
2MP Gokyo Food & Chemical Co., LTd. Osaka, Osaka, Japan

【Introduction】

Many functional food ingredients, such as polyphenols and fat-soluble vitamins, exhibit poor water solubility, which limits their absorption, stability, and application in easily consumed functional foods such as beverages. Curcumin is a representative example of a poorly soluble bioactive compound. Tamarind seed polysaccharide (TSP), a natural thickening polysaccharide derived from the seeds of Tamarindus indica L., is widely used in food and cosmetic formulations. Previous studies have reported that hydrolyzed TSP with a lower molecular weight can enhance the water solubility of curcumin. Building upon this finding, we investigated whether low-molecular-weight TSP (LMW-TSP) could improve the solubility and emulsifying ability of other poorly soluble substances.

【Method】

LMW-TSP was prepared through a controllable depolymerization process that is easier to regulate than conventional enzymatic hydrolysis. The solubilizing and emulsifying abilities of the resulting LMW-TSP samples were compared with those of native TSP by measuring the absorbance at 440 nm and 300 nm, using curcumin and fat-soluble vitamins as model compounds. Their physicochemical properties were also evaluated by viscosity measurements using a rheometer. Furthermore, their stability was assessed by measuring the absorbance of dispersions of curcumin or fat-soluble vitamins stored for a certain period at a specific temperature.

【Results】

We identified a distinct molecular-weight range of LMW-TSP that effectively enhanced the solubility of curcumin, differing from previously reported ranges. Furthermore, LMW-TSP exhibited a unique emulsifying effect on fat-soluble vitamins, particularly vitamin E. These results suggest that LMW-TSP may facilitate nutrient dispersion and absorption, contributing to the development of novel functional food ingredients.

1) Lang W., Tagami T., Kang H.J., Okuyama M., Sakairi N., Kimura A. (2023). Partial depolymerization of tamarind seed xyloglucan and its functionality toward enhancing the solubility of curcumin. Carbohydrate Polymers, 307, 120629.