School of Life Science and Biotechnology, Yangtze Normal Univ., Chongqing, 408100, China.
Chongqing Collaborative Innovation Center for Functional Food, Chongqing Univ. of Education, Chongqing, 400067, China.
J Food Sci. 2019 Apr;84(4):726-737. doi: 10.1111/1750-3841.14500. Epub 2019 Mar 15.
The current study evaluated the effects of vacuum drying on the whole polyphenol profile of loquat fruit, including extractive and nonextractive polyphenols. Absorbance analysis determined that total polyphenol content and antioxidant levels were higher in loquat fruit vacuum dried at 140 °C than in loquat fruit vacuum dried at 70 °C. The results of ultra-HPLC-triple quadruple mass spectrum analysis showed that 15 phenolic acids and 17 flavonoids were found in dried loquat fruit. Multivariate integrative (MINT) sparse partial least square-discriminant analysis showed that vacuum drying affects the polyphenol profile of loquat fruit. Co-analysis of principal component analysis, partial least square-discriminant analysis, and orthometric partial least square-discriminant analysis revealed that vacuum drying mainly changed the content of chlorogenic acid, cryptochlorogenic acid, protocatechuic acid, phloretin, and hesperidin in loquat fruit. Chlorogenic acid (12.020 to 39.153 µg/g d.b. [dried base weight]), the main polyphenol in dried loquat fruit, was degraded to caffeic acid (0.028 to 2.365 µg/g d.b.) and protocatechuic acid (0.014 to 18.285 µg/g d.b.) during vacuum drying. Moreover, vacuum drying also induced the isomerization of chlorogenic acid into cryptochlorogenic acid (1.628 to 12.737 µg/g d.b.). These results might be used to develop dried loquat fruit with high levels of polyphenols and antioxidant activity. PRACTICAL APPLICATION: Interests in polyphenols of loquat fruit had increased greatly because of their possible role in health benefits. This work provided a holistic insight in the effects of vacuum drying on polyphenols profile of loquat fruit. Current results have contributed to the development of vacuum-drying method, which produced loquat fruit rich in polyphenols. Furthermore, it also suggested that multivariate analysis was a feasible method to reveal the important changes of polyphenols profile during food processing.
当前的研究评估了真空干燥对枇杷果实中包括可提取和不可提取多酚在内的全多酚谱的影响。吸光度分析表明，在 140°C 下真空干燥的枇杷果实的总多酚含量和抗氧化水平高于在 70°C 下真空干燥的枇杷果实。超高效液相色谱-三重四极杆质谱分析结果表明，在干燥的枇杷果实中发现了 15 种酚酸和 17 种类黄酮。多变量综合（MINT）稀疏偏最小二乘判别分析表明，真空干燥会影响枇杷果实的多酚谱。主成分分析、偏最小二乘判别分析和正交偏最小二乘判别分析的共分析表明，真空干燥主要改变了枇杷果实中绿原酸、隐绿原酸、原儿茶酸、根皮素和橙皮苷的含量。绿原酸（12.020 至 39.153 µg/g d.b. [干基重量]）是干燥枇杷果实中的主要多酚，在真空干燥过程中降解为咖啡酸（0.028 至 2.365 µg/g d.b.）和原儿茶酸（0.014 至 18.285 µg/g d.b.）。此外，真空干燥还诱导绿原酸异构化为隐绿原酸（1.628 至 12.737 µg/g d.b.）。这些结果可用于开发具有高多酚和抗氧化活性的干燥枇杷果实。
由于其在健康益处方面的可能作用，人们对枇杷果实中的多酚越来越感兴趣。这项工作全面了解了真空干燥对枇杷果实多酚谱的影响。目前的结果有助于开发富含多酚的真空干燥方法，生产出的枇杷果实。此外，这也表明多元分析是揭示食品加工过程中多酚谱重要变化的可行方法。
