Jingnan Zang,Mingmin Qing,Yanqiu Ma,Yujie Chi,Yuan Chi
The quality changes in whole egg powders (WEP) during accelerated storage ( 40 °C, 50 °C, and 60 °C for 35 days ) were characterized by monitoring its moisture, pH, color, volatile flavor component, sensory attribute, particle size, and lipid oxidation. The general stability index (GSI) and multivariate accelerated shelf-life test (MASLT) were used to estimate the shelf-life of WEP. GSI evaluated the sensory scores, hydroperoxide (ROOH) content, malondialdehyde content, and acid value (AV), representing the shelf-life quality loss of WEP. For the MASLT, the data set was spatially compressed by principal components analysis (PCA) to obtain scores for the time-dependent components for further shelf-life evaluation. The predicted shelf-life at 25 °C storage using the GSI and MASLT model were 500 and 452 days, respectively. Overall, the MASLT model was more comprehensive and considered a more stringent predictor of shelf-life.
A novel strategy for ovotransferrin (OVT) detection by tracing the “on-off-on” fluorescence signals of quantum dots (QDs) and gold nanoparticles (AuNPs) utilizing fluorescence measurements were established in this article. The immune interaction between QDs-OVT and anti-OVT-AuNPs leads to drastic quenching (turning off) of the donor by a fluorescence resonance energy transfer (FRET) process. After the addition of free OVT, anti-OVT-AuNPs peel off from the QDs-OVT surface and bind to free OVT due to competitive immunoreactions, resulting in the restoration of the fluorescence intensity of QDs (turning on). Consequently, this process can be utilized for the selective detection of OVT via optical responses. Under optimal conditions, the fluorescence intensity of the system increased linearly with increasing concentrations of OVT from 0.05 to 3.8 μg/mL. The limit of detection of OVT was 23.55 ng/mL. This method was applied to the analysis of OVT in egg powder samples. Furthermore, the strategy provided in this work could be conveniently followed to establish similar immunosensors for the rapid detection of other proteins with corresponding antibodies.
危险品化学品经营许可证（带存储）