Application of alginate and chitosan edible films incorporating natural antimicrobial agents | |
| Author | Yudi Pranoto |
| Call Number | AIT Diss. no.AE-04-06 |
| Subject(s) | Meatballs--Preservation Chitosan Alginates Anti-infective agents |
| Note | A dissertation submitted in partial fulfillment ofthe requirements for the degree of Doctor of Engineering, School of Environment, Resources and Development |
| Publisher | Asian Institute of Technology |
| Series Statement | Dissertation ; no. AE-04-06 |
| Abstract | Food quality and safety demands are becoming more and more intensive and specific with more information available to the buyers. Consumer awareness for safe, high quality, long shelf life, fresher, minimally processed and ready to eat foods has increased in recent times. The use of edible films or coatings is one of the most effective methods in maintaining the quality and extending shelf life of processed foods. They can also function as a carrier of ingredients, such as antioxidants and antimicrobial agents. Alginate and chitosan are polysaccharides, abundantly available as natural materials. Coating meat products with alginate and chitosan has been shown to protect moisture loss, retard microbial growth and reduce lipid oxidation. In addition, it is known that some spice oils have antimicrobial and antioxidative activity. There is a limited research about employing these natural agents from plants to produce active edible films or coatings for foods preservation. This study was carried out to utilize the beneficial potency of natural substances (Spice oils) by incorporating into alginate and chitosan films to obtain active edible films and coatings. Initially, garlic, citronella and onion oils were tested for antimicrobial and antioxidative activities to select the most potent one. Antimicrobial films were then studied by incorporating antimicrobial agents such as garlic oi] (selected oil), potassium sorbate and nisin. The latter two are well known chemical and (bacteriocin) antimicrobial agents respectively. Five food pathogenic bacteria such as Escherichia coli, Salmonella wphimurium, Staphylococcus azrreus, Lister-11 monocytogenes and Bacillus cererrs were used to test antimicrobial activity of edible films. Meatball was used as a model product to examine the efficacy of active edible coatings for quality preservation. When tested against the above mentioned bacteria, it was found that garlic oil had better antimicrobial activity than citronella and onion oils. Its antioxidant activity measured using 1,1-diphenyl-2—picrylhydrazyl (DPPI—I) and deoxyribonucleic acid (DNA) cleavage protection methods was also found to be better than the other oils. The addition of glycerol at 40% (w/w of film materials) as a plasticizer modified the mechanical, physical and microstructural properties of alginate and chitosan films. In the alginate films, glycerol reduced tensile strength from 73.36 to 66.11 MPa, while in chitosan films it reduced tensile strength from 49.63 to 6.53 MPa. The elongation at break for alginate film increased slightly from 2.65 to 4.05% by addition of glycerol. The elongation at break for chitosan films was from 6.21 to 30.96%. In addition, glycerol caused an increase in water vapor permeability (WVP) value from 16.13 to 20.32 g.mm/m2.day.kPa in alginate films and from 23.09 to 26.72 g.mmx’m3.day.kPa in chitosan films. Glycerol addition reduced the microstructure cavities in alginate films, while in chitosan film it modified its compact structure in multilayers as observed by 3 Scanning Electron Microscopy (S EM). As chitosan and alginate have complementary prOperties in terms of charge, composite and bilayer films were made. Composite films made of varying ratios between alginate and chitosan did not result in films with desirable characteristics. In bilayer films, it was found that laminating chitosan onto alginate film could not replace the role of Ca ion as crosslinking agent in term of mechanical prOperties. Bilayer films made from alginate |
| Year | 2004 |
| Corresponding Series Added Entry | Asian Institute of Technology. Dissertation ; no. AE-04-06 |
| Type | Dissertation |
| School | School of Environment, Resources, and Development (SERD) |
| Department | Department of Food, Agriculture and Natural Resources (Former title: Department of Food Agriculture, and BioResources (DFAB)) |
| Academic Program/FoS | Agricultural and Food Engineering (AE) |
| Chairperson(s) | Rakshit, Sudip.K.; |
| Examination Committee(s) | Salokhe, Vilas M.;Nguyen T. Kim Oanh;Phaisan Wuttijumnong;Park, Hyun J.; |
| Scholarship Donor(s) | Quality for Undergraduate Education Project Government of indonesia,; |
| Degree | Thesis (Ph.D.) - Asian Institute of Technology, 2004 |