Development of Cellulose Nanocrystal Reinforced Anchote (Coccinia abyssinica) Starch Based Antimicrobial Food Packaging Film
| dc.contributor.advisor | Anuradha Jabasingh (Assoc. Prof) | |
| dc.contributor.advisor | Shegaw Ahmed (Asst. Prof.) | |
| dc.contributor.author | Habtamu Shebabaw (PhD) | |
| dc.date.accessioned | 2023-12-14T14:51:28Z | |
| dc.date.available | 2023-12-14T14:51:28Z | |
| dc.date.issued | 2023-11 | |
| dc.description.abstract | Food packaging is a critical component of the food supply chain, providing protection from contamination, spoilage, and damage. However, the use of synthetic plastics in food packaging has been linked to a number of environmental and health concerns. In recent years, there has been growing interest in the development of sustainable food packaging materials that are biodegradable, compostable, and non-toxic. Anchote starch is a renewable resource that is produced from the roots of the anchote plant. Anchote starch has excellent film-forming properties and can be used to produce biodegradable food packaging films. Cellulose nanocrystals (CNCs) are a promising material for use in sustainable food packaging. CNCs are a natural, biodegradable, and non-toxic material that has excellent mechanical, optical, and antimicrobial properties. Rosemary essential oil is a natural antimicrobial agent that has been shown to inhibit the growth of a variety of bacteria and fungi. The addition of rosemary essential oil to food packaging films can help to improve the antimicrobial properties of the film and protect food from spoilage. The purpose of this study was to develop and characterize CNC reinforced anchote starch-based antimicrobial food packaging film containing rosemary essential oil. Anchote CNC (AnchCNC) was extracted from anchote bagasse (AnchB) by acid hydrolysis method. Anchote starch based antimicrobial nanocomposite (AS/AnchCNC/REO) films incorporated with anchote cellulose nanocrystals (AnchCNC) (1, 3 and 5%) and rosemary essential oil (REO) (2, 4, and 6%) were prepared by the solvent casting method. The chemical components of AnchB and AnchCNC were determined. AnchB, Anchote cellulose (AnchC), and AnchCNC were characterized by Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), X-ray diffraction (XRD), scanning electron microscopy (SEM), and size distribution analysis. The thickness, moisture content, water solubility, water vapor permeability (WVP), mechanical properties and antimicrobial properties of Anchote starch (AS) and AS/AnchCNC/REO films were analyzed. Films containing (3% AnchCNC; 2% REO) and (5% AnchCNC; 2% REO) were chosen based on better tensile strength and their FTIR, thermal, and morphological characteristics were examined. The polyphenol content and antioxidant activity (DPPH inhibition) of films were also determined. The migration of polyphenol from the films to water and ethanol food simulant was studied at 30 °C after 7 days. The release rate and diffusion coefficient of polyphenol migration from the film sample F33 (5% AnchCNC, 6% REO) into water food simulant were determined by overall kinetics and diffusion modeling at 30, 40, 50 and 60 °C. The stability of polyphenol at an ambient storage temperature of 25 °C, as well as the antimicrobial application of the films for meat preservation was evaluated. The chemical treatments (alkali treatment, bleaching, and acid hydrolysis) effectively removed hemicelluloses and lignin from AnchB. The thermal stability of AnchCNC was reduced after acid hydrolysis due to the introduction of sulfate groups. XRD measurements revealed an increase in the crystallinity by 160 % after the chemical treatments. SEM images clearly exhibited an effective removal of the amorphous fractions after the chemical treatments. Zeta sizer analysis showed that AnchCNC had an apparent average diameter of 92 nm and zeta potential value of -21.0 mV. The tensile strength (TS) and WVP of anchote starch films were both dramatically improved by increasing the amount of AnchCNC. A significant reduction in the WVP of films was seen when the amount of REO was increased. The TS property of the films was found to decrease as the concentration of REO was increased. The TS of the AS (control) film was 9.42 MPa. Films containing (3% AnchCNC; 2% REO) and (5% AnchCNC; 2% REO) had shown the highest TS values of 23.41 MPa and 23.44 MPa, respectively. With the addition of 5% AnchCNC and 6% REO, the WVP of anchote starch film was decreased from 8.72 × 10-11 gH2O/Pa.m.s to 3.11 × 10-11 gH2O/Pa.m.s. The antimicrobial films showed satisfactory antimicrobial efficiency against E. coli, Staphylococcus aureus, and Listeria monocytogenes. REO significantly contributed to the antimicrobial efficiency of films. A sample containing the highest percentage (5% AnchCNC and 6% REO) recorded the highest antibacterial efficiency. TGA results showed films containing, 3 % AnchCNC; 2% REO (F21) and 5 % AnchCNC; 2 % REO (F31) had better thermal properties than the control (AS) film. The polyphenol content of films was in the range of 1.8 to 6.11 mg GAE/g dried films. The percentages of DPPH inhibition were between 15 to 53%. The film with highest AnchCNC and REO (5% AnchCNC, 6% REO) had the highest levels of polyphenols and DPPH inhibition. The results showed that the polyphenol content and antioxidant activity of films were increased proportionally with increasing AnchCNC and REO content. The total polyphenol concentrations that migrated to aqueous medium at 30 °C after 7 days were in the range of 17 to 60 mg GAE/kg food simulant for water food simulant. As expected, film sample F33 with (5% AnchCNC, 6% REO) had the highest concentration for the migration of polyphenols. The initial release rate of polyphenol, νo for film, F33 at four different temperatures, determined from the overall firstorder kinetics model were in the range of 8.3 × 10-7 to 36 × 10-7 g/s. The release of polyphenol into water food simulant at different temperatures were consistent to short-term and long-term diffusion models with diffusion coefficient values between 5.0 × 10-12 and 9.1 × 10-16 m2/s. The films produced displayed good antibacterial activity against the growth of E. coli, L. monocytogenes and S. aureus on meat products. The film with AnchCNC (5%) and REO content of (6%) were found to extend the shelf-life of meat beyond 50%, suggesting that the film may have great potential in active packaging for extending the shelf-life of foodstuffs. The findings implied that the film would have significant potential for active packaging to increase the shelf life of food products with good mechanical and barrier capabilities. | |
| dc.identifier.uri | http://etd.aau.edu.et/handle/123456789/999 | |
| dc.language.iso | en_US | |
| dc.publisher | Addis Ababa University | |
| dc.title | Development of Cellulose Nanocrystal Reinforced Anchote (Coccinia abyssinica) Starch Based Antimicrobial Food Packaging Film | |
| dc.type | Thesis |