ผลของตัวออกซิไดส์และการบ่มด้วยความร้อนต่อสมบัติของฟิล์มไข่ขาว

• Main Author: อินท์วาริน กิตติอัครศรีกุล
• Other Authors: ธนจันทร์ มหาวนิช
• Format: Theses and Dissertations
• Language: Thai
• Published: จุฬาลงกรณ์มหาวิทยาลัย 2017
• Online Access: https://digiverse.chula.ac.th/Info/item/dc:34099
• Institution: Chulalongkorn University

The objective of this study was to investigate the effect of type and concentration of oxidizing agents as well as the effect of temperature and time of heat curing of dried film on egg albumen film properties. In the first part of the study, the effect of type and concentration of oxidizing agents was explored. The oxidizing agents used in this study were hydrogen peroxide, sodium periodate, and sodium hypochlorite. Oxidizing agent concentration was varied as 0.02, 0.04 and 0.06 M. Tensile strength and elongation at break of the films added with oxidizing agent were significantly greater than those the control (p≤0.05). In general, the films treated with sodium periodate exhibited greater tensile strength and elongation at break than those treated with hydrogen peroxide and sodium hypochlorite. The film added with 0.06 M sodium periodate demonstrated the highest tensile strength (2.73 MPa) and elongation at break (63.89%), which were 425% and 326% increase as compared to the control. Disulfide cross-linking was denoted using Raman spectroscopic technique. Oxidative treatments also affected optical properties of the egg albumen film. Decreasing transparency was demonstrated in the oxidized films. The films added with sodium periodate and those added with sodium hypochlorite displayed yellow and yellow-orange hue, respectively, while those added with hydrogen peroxide were similar to the control in terms of color. The surface of the films treated with oxidizing agent signified increasing hydrophobicity. Reduction in water solubility and water vapor permeability was also induced by oxidative treatment. In the second part of the study, the effect of temperature and time of heat curing of dried film was investigated. The film used in this part was the egg albumen film treated with 0.06 M hydrogen peroxide. Curing temperature was varied at 4 levels (40, 60, 70 and 80ºC) and curing time was varied at 3 levels (24, 48 and 72 hr). The heat-cured films exhibited significantly greater tensile strength and lower elongation at break as compared to the uncured control (p≤0.05). As curing temperature and time increased, tensile strength was found to increase (p≤0.05) while elongation at break was unaffected (p>0.05). The film cured at 80ºC for 72 hr exhibited the greatest tensile strength of 9.55 MPa, which was 683% of that of the control. Disulfide cross-linking was attested by Raman spectrum. In terms of optical properties, heat curing was found to minimally affect color of the films. Even though the film samples possessed different hue angle, the extremely low chroma made all films appeared grey to the naked eyes. Heat curing resulted in film surface with increasing hydrophobicity. A film with hydrophobic surface (i.e., that with contact angle of greater than 90º) could be produced by curing at higher temperature for a longer time. Additionally, the heat-cured film exhibited a reduction in water solubility and water vapor permeability.