Ying Liu,Wenjuan Qu,Yuxuan Liu,Yuhang Feng,Haile Ma,Jamila A. Tuly
Cell wall-degrading enzymes' activities under infrared treatment are vital for peeling; it is critical to elucidate the mechanisms of the novel infrared peeling in relation to its impact on cell wall-degrading enzymes . In this study, the activities, and gene expressions of eight degrading enzymes closely related to pectin, cellulose and hemicellulose were determined. The most influential enzyme was selected from them, and then the mechanism of its changes was revealed by molecular dynamics simulation and molecular docking . The results demonstrated that infrared had the most significant effect on β-glucosidase among the tested enzymes (increased activity and up-regulated gene expression of 195.65 % and 7.08, respectively). It is suggested infrared crucially promotes cell wall degradation by affecting β-glucosidase. After infrared treatment, β-glucosidase's structure moderately transformed to a more open one and became flexible, increasing the affinity between β-glucosidase and substrate (increasing 75 % H-bonds and shortening 15.89 % average length), thereby improving β-glucosidase's activity. It contributed to cell wall degradation. The conclusion is that the effect of infrared on the activity, gene expression and molecular structure of β-glucosidase causes damage to the peel, thus broadening the applicability of the new infrared dry-peeling technique, which has the potential to replace traditional wet-peeling methods.
Ying Liu,Wenjuan Qu,Yuxuan Liu,Jamila A Tuly,Haile Ma
Food quality is greatly impacted by traditional heat methods for polygalacturonase (PG) inactivation; therefore, it's imperative to develop a novel infrared (IR) inactivation approach and identify its mechanism. Utilizing molecular dynamics (MD) simulation, this study verified the PG's activity, structure, active sites, and substrate channel under the single thermal and non-thermal effects of IR. PG activity was significantly reduced by IR, and structure was unfolded by increasing random coils (65.62 %) and decreasing β-sheets (29.11 %). MD data indicated that the relative locations of PG's active sites were altered by both IR effects, and the enzyme-substrate channel was shortened (10.53 % at 18 μm and 15.79 % at 80 °C). The thermal effect of IR on the inactivation of PG was significantly more pronounced than its non-thermal effect. This study unveiled the mechanism by which the infrared disrupted PG's activity, active sites, and substrate channels; thus, it expanded the infrared technique's efficacy in enzyme control.
In order to solve the problems of nutrient loss and flavor defect of the first-grade refined rapeseed oil, this study innovatively proposed an optimal strategy to enhance its nutrition and aroma. The microwaved-, roasted- and infrared-treated rapeseed cakes were mixed with primary rapeseed oil and then ultrasonically heated to obtain MCO, RCO and ICO, which were evaluated in terms of oxidation indexes, lipid concomitants and volatile aroma components. The results found that MCO showed the best comprehensive performances when the heating temperature was 120 °C: squalene, tocopherol and total phenol contents increased by 12–18 %, 20–30 % and 10–15 %, respectively, and key aroma substances (furfural) enhanced nutty notes. Correlation analysis showed that squalene ( r = 0.82) and polyphenols ( r = 0.79) had significant negative correlation with key flavor substances by inhibiting oxidation. This study established a process for synergistically enhancing rapeseed oil nutrition and flavor, providing a theoretical basis and technical path for high-value-added product development.
危险品化学品经营许可证（带存储）