Laboratory for Separation Processes and Product Design, Faculty of Chemistry and Chemical Engineering, University of Maribor, Smetanova ulica 17, 2000 Maribor, Slovenia.
Faculty of Medicine, University of Maribor, Taborska ulica 8, 2000 Maribor, Slovenia.
Molecules. 2020 Dec 17;25(24):5981. doi: 10.3390/molecules25245981.
Graham flour is a form of whole wheat flour made by grinding the endosperm and is thus also the most nutritious. Generally, the enzyme polyphenol oxidase (PPO) catalyzes two different reactions in the presence of molecular oxygen: the hydroxylation of monophenols to ortho-diphenol and the oxidation of -diphenol to -quinone. The purpose of the work was to inactivate PPO activity to extend the shelf life of graham flour and at the same time preserve all the of its high-quality properties. The influence of supercritical CO (scCO) treatment on PPO activity in graham flour was investigated. First, graham flour was exposed to scCO conditions, then the proteins were extracted, and in the last step the concentration of total proteins and the specific activity of the PPO enzyme were determined by spectrophotometric assay. PPO activity decreased with an increase in treatment pressure. Furthermore, the flour quality characteristics that meet all needs for wheat end-use products after scCO treatment have been preserved. No major changes in the structure of the granulate or shape of the flour particles were observed. A slightly reduced value of the moisture content in scCO-treated graham flour also implies an extension of the shelf life.
全麦面粉是一种由胚乳磨制而成的全谷物面粉，因此也是最有营养的。通常情况下，多酚氧化酶（PPO）在分子氧存在的条件下催化两种不同的反应：单酚的羟化生成邻二酚和邻二酚的氧化生成醌。本研究的目的是通过钝化 PPO 活性来延长全麦面粉的保质期，同时保持其所有高质量特性。研究了超临界 CO（scCO）处理对全麦面粉中 PPO 活性的影响。首先，将全麦面粉暴露于 scCO 条件下，然后提取蛋白质，最后通过分光光度法测定总蛋白质浓度和 PPO 酶的比活性。随着处理压力的增加，PPO 活性降低。此外，scCO 处理后，面粉的质量特性满足所有小麦最终用途产品的需求得以保留。未观察到颗粒的结构或形状有明显变化。scCO 处理的全麦面粉中水分含量略有降低，这也意味着保质期的延长。
