Bioactive Films and Hydrogels Based on Potato Starch and Phenolic Acids using Subcritical Water Technology

  • Author / Creator
  • Biodegradable polymers as an eco-friendly alternative to traditional plastics have raised increasing attention by the packaging industry, especially for food and pharmaceutical applications. Phenolic acids found in many plants exert antioxidant and antimicrobial activity, which are considered beneficial to human health. In this study, a new approach based on subcritical water (SCW) technology has been developed, which allowed the modification and production of potato starch polymers with the use of gallic acid. First, solubility behavior of gallic acid, 4-hydroxybeozic acid and 3-(4-hydroxyphenyl)-propionic acid in subcritical water was determined at different pressures and temperatures using a dynamic system. The solubility of these phenolic acids in water increased with temperature. Then, gallic acid was used to produce bioactive films and hydrogels using SCW technology. Four processing parameters, gallic acid/starch ratio, temperature, glycerol/starch ratio and pressure, were evaluated based on film structural, optical, mechanical, and functional properties. Optimum film in terms of mechanical properties was achieved using 40 mg gallic acid/g starch and 0.5 g glycerol/g starch with 5% potato starch solution at 100 °C and 30 bar. Starch bioactive hydrogels were also produced and characterized in terms of structural, physicochemical and functional properties (swelling degree, and phenolic releasing capacity). The optimum hydrogel in terms of porosity and swelling degree was found. Films produced can be potentially used as functional food packaging materials or carriers for bioactive compounds. The starch based hydrogel can also be used as an absorbent for food and non-food application.

  • Subjects / Keywords
  • Graduation date
    Spring 2015
  • Type of Item
  • Degree
    Master of Science
  • DOI
  • License
    This thesis is made available by the University of Alberta Libraries with permission of the copyright owner solely for non-commercial purposes. This thesis, or any portion thereof, may not otherwise be copied or reproduced without the written consent of the copyright owner, except to the extent permitted by Canadian copyright law.