Preparation And Characterization Of Functional Starch-based Oral Fast Dissolving Film

Recently,oral fast dissolving film（ODF）as a new way of delivering active ingredients has been widely studied.It is a thin film similar in size,shape and thickness to stamp,prepared from a hydrophilic polymer.ODF has large relative surface areas.When placed in the mouth,it can disintegrate quickly and release active ingredients in mouth without the need for water.It is easy to carry and sui Tablefor all ages.Currently,the market for ODF is mainly concentrated in North America.Its listed products are few,many products are in research and development status in China.In the study,pre-gelatinized cassava starch was used as the main film-forming polymer.The effect of film-making process conditions and formulations on the properties of starch-based ODF was investigated by single-factor and response surface experiments.In addition,the effects of the addition ofβ-cyclodextrin,catechin and catechin/β-cyclodextrin complexs on the properties of the ODF were compared by disintegration time,mechanical strength,scanning electron microscopy,thermogravimetry,infrared,antibacterial and antioxidant tests.Functional ODF with excellent disintegration properties,mechanical properties,antibacterial properties and antioxidant capacity was successfully prepared by the addition of catechin/β-cyclodextrin complexs.The main contents and conclusions of the study include:（1）The optimum process conditions for the preparation of pre-gelatinized cassava starch-based ODF was determined by single-factor and response surface experiments:the amount of plasticizer sorbitol was 35%（w/w,based on starch mass）,the dispersion temperature of starch was 50°C,the dispersion time of starch was 25 min and the drying temperature was 36°C.The disintegration time of ODF was 17.04 s,the tensile strength was 11.60 MPa and the elongation at break was 11.23%after optimization.（2）The effect ofβ-cyclodextrin on the disintegration time and mechanical properties of pre-gelatinized cassava starch-based ODF was investigated.Thickness and disintegration time of the ODF increased with the addition ofβ-cyclodextrin.The ODF has excellent mechanical properties with a tensile strength of 37.58 MPa and an elongation at break of 3.87%when the concentration ofβ-cyclodextrin is 10%（w/w）.Microstructural analysis indicated that the presence ofβ-cyclodextrin promoted a more uniform distribution of starch in the film matrix,which resulted in a flatter ODF surface.The addition ofβ-cyclodextrin increased the thermal stability of ODF,its thermal decomposition temperature from 311°C to 320°C.The degree of short-range ordering of starch in the film matrix was significantly reduced.In conclusion,β-cyclodextrin affected the starch molecules in two main ways:（i）during stirring,β-cyclodextrin dispersed into the film-forming solution and promoted the uniform dispersion of starch molecules;（ii）during film formation,at low concentrations（?10%,w/w）,β-cyclodextrin was excluded from the starch chains,which increased the chance of cross-linking between starch molecules and then promoted the formation of a complete network structure in the film matrix;at high concentrations（>10%,w/w）,excessβ-cyclodextrin was difficult to be excluded,which limited the proximity of starch chains to each other and prevented the formation of a complete network structure.（3）The effects of catechin or catechin/β-cyclodextrin complexes on the physicochemical properties of pre-gelatinized cassava starch-based ODF were investigated.The disintegration time increased and the tensile strength improved of the ODF with the addition of catechin.With the addition of the complexes,the thickness increased significantly.The disintegration time was decreased and then increased,the ODF with 10%complex has the lowest disintegration time（9.03 s）.The low amount of the complexes（10%）improved the mechanical properties of the ODF.The addition of catechin had little effect on the thermal stability of the ODF.It did not lead to any change in the infrared spectra of the ODF.Catechin was only present as a filler in the film matrix.When the complexes were added,the thermal stability of ODF was improved and the infrared spectra were shifted from 3281 cm^-1 to 3265 cm^-1.The presence of the complexes enhanced the interactions between starch molecules.In the preparation process of ODF,the effect of the complexes on the polysaccharides system was similar to that ofβ-cyclodextrin.ODF had a significant inhibition effect on Staphylococcus aureus and its inhibition effect was enhanced with the increase of complex concentration.ODF with 15%-25%complex had a high inhibition rate（?96.57%）against Streptococcus mutans.In addition,the antioxidant capacity of functional ODF was also investigated during storage.After 28 days of storage（40°C and 75%relative humidity）,the total antioxidant capacity of ODF was above 85%and the DPPH·radical scavenging capacity was above 70%.It indicated that ODF has a good protective effect for catechin.Finally,storage stability of ODF was analyzed.ODF had the best mechanical properties within 75 days.（4）To further improve the sensory characteristics of ODF with catechin/β-cyclodextrin complex,the formulation with 15%complex addition was used as the base formulation and the optimal addition of sweetener,saliva stimulant and flavoring agent in the functional ODF was determined by single-factor and orthogonal experiments:sucralose addition of 1.5%（w/w）,citric acid addition of 3%（w/w）and green tea flavoring addition of 3%w/w.After formulation optimization,disintegration time of the ODF was25.47 s,tensile strength was 20.53 MPa,elongation at break was 4.10%and the sensory score was 91.1 points.