Optimization of Microwave-Ultrasound-assisted Enzymatic Hydrolysis extraction of iodine amino acids in laminaria by high performance liquid chromatography with a photodiode array detector

Abstract

A rapid and efficient method for extracting Mnoiodo-tyrosine (MIT) and Diiodo-tyrosine (DIT) from laminaria was successfully developed. The laminaria samples were first pretreated with microwaves, before the MIT and DIT were extracted with an ultrasonic water bath. A response surface experiment was used to optimize the extraction conditions, and ultimately the best conditions for extraction were successfully identified, which were a microwave power of 250 W, a microwave time of 4.7 min, an addition of 0.31 g of pancreatin, and 4.22 h in the ultrasonic water bathe. A simple and low-cost High-Performance Liquid Chromatography High-Performance Liquid Chromatography Photodiode Array (HPLC-PDA) detection method for MIT and DIT was established. The detection limits ranged from 50.6 to 320.6 ng/g. Scanning Electron Microscopy (SEM) was used to observe the degree of damage to the laminaria cells from the different extraction methods. The molecular weight distribution of the organic iodine of the original laminaria and the laminaria after enzymatic hydrolysis was studied by Size-Exclusion Chromatography Inductively Coupled Plasma Mass Spectrometry (SEC-ICP-MS).