Influence of media milling and addition of ultrafine cellulose on the mechanical properties of starch-base film

• Main Authors: Yu-Chin Shen, 沈育致
• Other Authors: 葉安義
• Format: Others
• Language: zh-TW
• Published: 2008
• Online Access: http://ndltd.ncl.edu.tw/handle/02937640031342842061

碩士 === 國立臺灣大學 === 食品科技研究所 === 96 === Plastic materials are generally applied matters in food packaging; however, it resulted in an environmental impact or pollution. Recently, environment friend materials from natural and renewable resources, which are biodegradable and biocompatible, have received great attention. Starch, an edible material with thermoplastic characteristics, is suitable for film formation; however, the starch-based film is too brittle to processing. Cellulose is an abundant polysaccharide in nature with high crystallinity, which has the potential to enhance the mechanical properties of starch-based film. In the present study, the influence of addition of ultrafine cellulose in starch-based film was studied by the application of media milling technique. Corn starch and cotton cellulose were fractured by media milling, and the static-light-scattering particle analyzer was applied to check the nano/submicron particles. Also, the scanning and transmission electron microscopes were used to observe the image of particles in nano/submicron scales. The rheological properties of milled starch and cellulose suspension were evaluated by dynamic rheometer. The apparent viscosity of starch and cellulose suspension was increased after media milling. Addition of ultrafine cellulose drove the decrease of apparent viscosity of native gelatinized corn starch. But, the apparent viscosity of gelatinized milled starch increased with ultrafine cellulose addition. The suspensions appeared to be a shear-thinning fluid and can be described by Herschel–Bulkley model. The suspensions were used to prepared starch-based film using casting method. The mechanical properties of films were studies by texture analyzer with tensile test. The Young’s modulus increased from 743 MPa for the native starch film to 1505 MPa for the milled starch film. The Young’s modulus increased from 743 to 1075 MPa as the addition of ultrafine cellulose. increased from 0 to 11% (w/w, base on the weight of starch). Media milling as well as the addition of ultrafine cellulose can enhanced mechanical properties of starch based film.