Effects of starch addition on the activity and specificity of food‐grade lipases

• Published in: Biotechnology and applied biochemistry 2019-07, Vol.66 (4), p.607-616
• Main Authors: Carpen, Aristodemo, Bonomi, Francesco, Iametti, Stefania, Marengo, Mauro
• Format: Article
• Language: English
• Subjects: Corn; Diglycerides; Emulsions; Fatty acids; Fatty Acids - chemistry; Fatty Acids - metabolism; Food; food‐grade lipases; Hydrolysis; Hydrolysis - drug effects; Intermediates; Kinetics; Lipase - chemistry; Lipase - metabolism; mono‐ and diglycerides; multiphasic systems; Oils & fats; Slurries; Starch; Starch - chemistry; Starch - metabolism; Starch - pharmacology; Substrate Specificity - drug effects; Substrates; Triglycerides; Triglycerides - chemistry; Triglycerides - metabolism; vegetable oils; Wheat
• ISSN: 0885-4513; 1470-8744
• DOI: 10.1002/bab.1761

Lipases are surface‐active enzymes, acting on their substrates at the polar/nonpolar interface in emulsions. This study was aimed to test whether their activity, specificity, and the rates of formation/degradation of the various hydrolysis intermediates (i.e., mono‐ and diglycerides of interest as surface‐active agents) could be modulated by adhesion of the triglyceride substrates as a thin layer on the surface of solids. These hypotheses were tested by using an array of food‐grade lipases used in bakery, testing various types of starch as the “solid” phase. Starch‐dependent increase in the hydrolysis rate was tested by pH‐stat techniques on pure triglycerides and on food‐grade oils in diluted emulsions. Starch‐related improvements in the rate of fatty acids release were most evident at temperatures above 40 °C, and when using maize starch instead of wheat starch. Starch‐dependent changes in the nature of the hydrolysis products were tested by chromatographic profiling of ethyl ether extracts from aqueous slurries containing up to 33% fat and 33% starch. Accumulation of mono‐ and diglycerides as hydrolysis intermediates was found to be modulated by the type of oil being used, by the reaction conditions, as well as by the enzyme nature and amount.