Abstract:The optimal conditions for producing Premna microphylla Turcz jelly from a fresh liquid extract of the plant were determined using single-factor experiments and response surface methodology, with the hardness, chewiness, elasticity, and sensory properties of the product used as response values. The physicochemical properties of the produced jelly, including its antioxidant capacity (free radical-scavenging ability) and total protein, total flavonoid, and pectin contents were also determined. Additionally, its inhibitory activities against α-amylase and α-glucosidase were established using in vitro enzyme activity inhibition assays. The results indicated the following as the optimal production conditions: 0.77% (m/m) of composite glue, 9.22% (m/m) of white sugar, and 0.09% (V/V) of citric acid. Under these conditions, the jelly hardness, chewiness, elasticity, and sensory score were 325.71 gf, 85.00 gf, 0.82, and 85.66, respectively. Moreover, its total protein, total flavonoid, and pectin contents were 5.96 mg/mL, 1.42 mg/g, and 4.36 μmol/g, respectively. The IC50 values for its DPPH and ABTS+ free radical-scavenging activities and total antioxidant capacity were 924.6, 1 013.0, and 614.9 mg/mL, respectively. Furthermore, the jelly significantly inhibited α-amylase and α-glucosidase activities. In summary, the successful optimization of the production process for P. microphylla jelly and preliminary analysis of its physiological properties offer valuable insights into the manufacturing techniques for producing this plant product as well as its potential biological functions.
