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All Journal Indonesian Food and Nutrition Progress
Yoshiyuki Ohta
Hiroshima University
Agriculture, Biological Sciences & Forestry

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A Simplified Method for Determination of Free Fatty Acids for Soluble and Immobilized Lipase Assay Djagal W. Marseno; Retno Indrati; Yoshiyuki Ohta
Indonesian Food and Nutrition Progress Vol 5, No 2 (1998)
Publisher : Indonesian Association of Food Technologists

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.22146/jifnp.77

Abstract

A simple and rapid method for determination of free fatty acids for soluble and immobilized lipase assay was developed. The free fatty acids could be determined within 10 min with less organic solvent used and the color developed was stable until 60 min. High correlation (r > 0.97) between fatty acids content (2 -10 pmole) and absorbance was observed for fatty acids with carbon number of 6 or higher. Hydrolysis activity of soluble and immobilized lipase could be measured with high sensitivity and reproducibility against incubation time and protein loading. The effect of various substrate concentrations and water against hydrolysis activity could also be measured. The method was suitable for routine analysis such as purification of lipase and continuous hydrolysis of fat and oil.
Immobilization of Lipase from Rhizopus delemar on Polyethylene Membrane Retno Indrati; Djagal W Marseno; Yoshiyuki Ohta
Indonesian Food and Nutrition Progress Vol 6, No 1 (1999)
Publisher : Indonesian Association of Food Technologists

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.22146/jifnp.67

Abstract

Rhizopus delemar lipase was immobilized by physical adsorption onto polyethylene membranes. The influence of membrane pore size and thickness on enzyme activity was studied. The immobilization efficiency was higher for the thicker membrane than thin one, this related to the large excess of area that the enzyme can occupy. The immobilization efficiency was also affected by enzyme loading, in which suppression was occurred at high enzyme loading. At the initial rate of hydrolysis reaction, the amount of enzyme bound, concentration of substrate, and membrane's thickness as related to the limitation of the substrate transfer affected the production of fatty acid. The thin polyethylene membrane was the best support since the enzyme immobilized on this support was stable during storage and possessed higher degree of hydrolysis and ability for subsequent reuses. Both membranes were regenerable by washing for fresh enzyme immobilization.
Co-Authors Djagal W Marseno Djagal W. Marseno Retno Indrati