Effects Of Ultraviolet Treatment On The Mechanical And Physical Properties Of Edible Starch Blend Films
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Date
2011
Authors
Mat Salleh, Ummi Shafiqah
Journal Title
Journal ISSN
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Publisher
Universiti Sains Malaysia
Abstract
Edible films made from sago, mung bean and corn starches were prepared using glycerol as the plasticizer, and then they were treated under ultraviolet (UV) radiation for 1, 2 and 3 h exposure time. Different blends were made by varying the ratios of sago: mung bean and sago: corn starches as follows: 100:0, 75:25, 50:50, 25:75, and 0:100. The pasting properties and amylose content of the starches then were measured. Control (untreated) and ultraviolet (UV) treated films were evaluated for thickness, mechanical properties, water vapor permeability (WVP), water solubility, X-ray diffraction, glass transition temperature and sorption isotherms. Fourier transform infrared (FTIR) spectroscopy was conducted to determine possible interactions or changes induced on UV treatments of sample. The general aim of this work was to confirm the hypothesis that UV treatment can crosslink starch, enhance the mechanical properties and affect the physical properties of starch films. The results indicated that pasting properties of each starch and the combinations affect the properties of films whereby corn starch (C100) had the lowest setback value and therefore could not develop edible film. The incorporation of a plasticizer (glycerol) resulted in more manageable films. The amylose content of mung bean starch (44.00 %) was higher than that of sago starch (25.40 %) which gave higher Young modulus (YM) and tensile strength (TS) values. All films (for YM and TS values) showed slight changes after treated under UV light for 1 h and increased significantly after 2 h exposure time. The sago: mung bean 25:75 starch film treated with UV for 2 h had the highest TS and YM value. While for WVP analysis, the UV treatment did not affect the properties of films. However, WVP for control films with different ratios showed
significant differences in which SM 75:25 gives the highest value of WVP. X-ray analysis showed a B-type pattern for control and treated films.
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Keywords
Effects of ultraviolet treatment , edible starch blend films