Qiyong Jiang,Meng Liu,Zhaosheng Wang,Rentang Zhang,Yuxiao Wang,Fengjun Guo,Qing Sun
Radical mediated reaction method was chosen to prepare ferulic acid grafted pectin (FA-P) to enhance the properties of the native pectin. HPLC and FTIR results presented that ferulic acid was successfully grafted onto the pectin molecule. Among them, FA-P conjugation with a mass ratio of 0.75:1 was the most effective with the highest grafting efficiency, emulsifying activity index and emulsifying stability index. Subsequently, FA-P (0.75:1) was used to emulsify resveratrol to prepare FA-P-R emulsion. Compared to the resveratrol emulsion emulsified with native pectin (P-R), FA-P-R had a lower ζ-potential and a 57.4% reduction in mean particle diameter. Scanning electron microscopy demonstrated that the particles of FA-P-R emulsion were more rounded, with flatter and smoother surfaces, suggesting the formation of a better emulsified morphology. In addition, the encapsulation efficiency, load capacity and light stability of FA-P-R increased by 31.6%, 31.5% and 28.0%, respectively, compared to P-R. The FA-P-R samples showed the best antioxidant properties among the four emulsions of FA-P-R, P-R, FA-P and pectin for the functional coatings prepared, with the highest DPPH and ABTS + radical scavenging activity. Finally, the FA-P-R functional coating for wrapping frozen limes was able to significantly inhibit the yellowing of frozen limes during freezing storage. The results highlight that the prepared FA-P-R functional coating can be used to inhibit the quality deterioration of frozen fruits and extend the freezing period.
Yellowing is a main discoloration in fresh-cut yam, which reduces consumer acceptance and, hence, the commodity value. Bisdemethoxycurcumin has been demonstrated to play important roles in fresh-cut yam yellowing. Considering the pharmacological properties and application in fruits and vegetables of diphenyliodonium iodide (DPI), the effects and mechanism of DPI treatment on bisdemethoxycurcumin accumulation in fresh-cut yam were analysed. The results showed that total bisdemethoxycurcumin in fresh-cut yam treated with DPI was markedly inhibited due to the significantly weakened phenylpropanoid pathway and bisdemethoxycurcumin biosynthesis. DPI was found to suppress the activities of major enzymes (phenylalanine ammonia lyase, PAL, cinnamate-4 hydroxylase, C4H; 4-coumarate coenzyme A ligase, 4CL), limit the levels of PAL, C4H and 4CL transcription and lower the contents of related metabolites in fresh-cut yam. Moreover, treatment with DPI inhibitor restrained the downstream transcription level of curcumin synthase (CURS), which had a significant impact on bisdemethoxycurcumin synthesis. Thus, our results confirmed that DPI was essential for inhibiting bisdemethoxycurcumin accumulation in fresh-cut yam through suppressed phenylpropanoid pathway and bisdemethoxycurcumin biosynthesis.
危险品化学品经营许可证（带存储）