Preparation and properties of raspberry functional chewable tablets

Raspberry possesses several health benefits such as antitumor, antioxidant, and blood sugar-regulating activities. In order to improve the use value of raspberries, the optimal preparation process of raspberry chewable tablets (RCT) and its physical, chemical, antioxidant, and hypoglycemic properties were investigated in this research. The optimum formulation of RCT was determined as 39.1% raspberry powder, 13.1% red beet root powder, 9.8% corn starch, 15% microcrystalline cellulose, 14% mannitol, 1% magnesium stearate, and 8% ethanol (75%) by single-factor experiment and response surface methodology using sensory evaluation score and hardness as parameters. RCT prepared using the optimal formulation had a hardness of 47.33 ± 2.31 N, brittleness of 0.33%, weight of 1.00 ± 0.03 g, and a color difference ΔE = 0.427. The total phenolic and total flavonoid contents of RCT were 18.610 ± 0.483 mg/g and 3.885 ± 0.061 mg/g, respectively. Meanwhile, seven phenolic compounds in RCT were determined by high-performance liquid chromatography. Free radical scavenging abilities ((1,1-diphenyl-2-picrylhydrazyl, DPPH), (2,2'-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid), ABTS), and ·OH), ferric ion-reducing antioxidant power and cell tests proved the significant antioxidant ability of RCT. The obvious inhibitory activities of RCT on α-glucosidase and α-amylase reflected its hypoglycemic potential. This study provided an important basis for the development of raspberry functional foods with antioxidant and blood glucose regulating potential.