Abstract
Incorporating probiotics into edible films offers an effective strategy for delivering viable microorganisms to the body. This study aimed to develop edible films based on three types of pregelatinized cassava starch-pregelatinized native starch (PNS), hydroxypropyl distarch phosphate (HDP), and hydroxypropyl starch (HS)-as carriers for Bacillus coagulans (BC). The interactions between probiotic powder and the polymer matrix, as well as the viability of B. coagulans during film drying and subsequent storage, were evaluated to assess the effectiveness of the films as protective delivery systems at room temperature (25 °C). The addition of BC altered the amorphous-to-ordered structure of the starch matrices. Surface morphology analysis showed BC aggregates on PNS films, whereas HDP and HS films retained smooth surfaces. Incorporation of BC increased the tensile strength and Young's modulus of PNS films but reduced their elongation at break. Additionally, BC decreased both the light transmittance and water contact angle in PNS films, while 1% BC increased the contact angle in HDP and HS films. BC had no significant effect on the solubility of PNS films but enhanced the solubility of HDP and HS films. Notably, B. coagulans maintained viability around 8 log CFU/g after 90 days of storage at room temperature, supporting the potential of pregelatinized starch-based films as effective probiotic carriers.