45D-2 |
Effect of selected parameters on the properties of edible film from water-soluble fish proteins |
T. BOURTOOM1, M. S. Chinnan2, P. Juntawat1, and R. Sanguandeekul1. (1) Dept. of Food Technology, Chulalongkorn Univ., Faculty of Science, Bangkok, Thailand, (2) Department of Food Science and Technology, University of Georgia, 1109 Experiment St., Melton Bldg., Griffin, GA 30223-1797 The fish proteins recovered from surimi processing are used in animal feed and fertilizer. Little is known of their edible forming properties for lack of research. To investigate the effect of pH, temperature and heating time on the film forming ability in terms of the mechanical and barrier properties. Freeze-dried water soluble fish proteins were dissolved in distilled water (3%w/v) to prepare film-forming solutions. The pH (9.5, 10 and 10.5) was adjusted prior to adding plasticizer (sorbitol). The solutions were heated (60, 70 and 80 oC) for the given time (10, 20 and 30 min) and poured into leveled non-stick trays to set. The cast films were dried at 35 oC, for 24 h and tested for tensile strength (TS) and elongation at break (%E) by Instron universal testing instrument, water vapor permeability (WVP) by water transmission unit (Permatran-W1A) and oxygen permeability (OP) by a MOCON unit (Ox-Tran 100A). Response surface methodology was used for experiment design and data analysis. The impact of pH and temperature was most significant, overall, on the film’s properties than heating time. TS and % E were highest at pH ~ 10.0 at 70 oC, while WVP and OP were at their lowest. There was a direct correlation between the films and proteins solubility and heating temperature, which reversed with change in pH. Film color was darker and more yellow with increase in the pH. The surface hydrophobicity and content of disulfide bond increased with increase in pH, while the available sulfhydryl group decreased. The fish protein films showed high barrier properties in terms of water and oxygen permeability. Further evaluation of the process parameters such as type and amount of plasticizer, chemical and enzymatic treatments will help to better understand their potential in food applications.
Session 45D, Food Packaging: General
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