Characterization and comparison of predominant aroma compounds in microwave-treated wheat germ and evaluation of microwave radiation on stability. (May 2020)

• Record Type: Journal Article
• Authors: Zhang, Yukun; Tang, Ning; Shi, Lin; Miao, Yuxin; Liu, Xu; Ge, Xinhui; Cheng, Yongqiang; Zhang, Xiuqing
• Is Part Of: Journal of cereal science. Volume 93(2020)
• Publication Date: 2020-05
• Subjects: Volatile substances -- Microwave radiation -- Wheat germ -- Stabilization; WG wheat germ -- MW microwave -- WI whiteness index -- BI browning index -- SPME solid phase microextraction -- GC-MS gas chromatography/mass spectrometry; Grain -- Periodicals; Cereal products -- Periodicals; Céréales -- Périodiques; Produits céréaliers -- Périodiques; Cereal products; Grain; Periodicals; 664.705
• DOI: 10.1016/j.jcs.2020.102942
• Languages: English
• ISSNs: 0733-5210

Abstract

Abstract: The present study was performed to evaluate the effects of microwave (MW) output power and treatment time on moisture content, lipase and lipoxygenase activities as well as colour changes of wheat germ (WG). In addition, the key aroma compounds in different MW-power-treated WG, which is of importance to the flavour of WG products, were also investigated. The obtained results showed that MW treatment maintained the inherent colour of WG and significantly reduced the moisture content (maximum reduction of 95%) and the activities of lipase and lipoxygenase (maximum reduction of 65% and 99%, respectively). In terms of aroma compounds, with the increase of the MW output power, the content of esters, alkanes, alcohols and acids decreased, while the content of heterocyclic compounds, nitrogen-containing compounds, aldehydes and ketones increased, providing more compounds with roasted flavour and less volatiles with grass-like flavour. Therefore, MW treatment was an effective stabilization method for WG utilization. Graphical abstract: Image 1090 Highlights: Microwave radiation processing led to significantly deactivate of lipase and lipoxygenase in a short period. Aroma compounds during stabilization processing were determined by SPME-GC-MS. Nitrogen-containing or heterocyclic compounds, aldehydes and ketones emerged or increased with higher-power microwave.