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Gynura bicolor DC (G. bicolor) is largely consumed as a vegetable in many parts of the world, and due to its content in anthocyanin can be considered as a health-promoting food. This study aimed to characterize the anthocyanin composition of G. bicolor and compare the effect of microwave vacuum drying (MVD) on the anthocyanin content with that of hot air drying (HAD). Anthocyanins were characterized using high-performance liquid chromatography-quadrupole-Orbitrap mass spectrometry (HPLC-Q-Orbitrap MS), which accurately identified five anthocyanin compounds. Delphinidin 3- O -neohesperidoside is the main anthocyanin compound found in G. bicolor. MVD decreased the drying time by 89% compared to HAD. MVD retained 87% of the total anthocyanins in G. bicolor , compared to 18% retained by HAD. This study revealed that MVD produced high-quality dried G. bicolor products, while exhibiting reduced processing times compared to those achieved using HAD. • Five anthocyanins were identified in fresh G. bicolor. • MVD significantly reduced the drying time in comparison to HAD. • MVD resulted in more effective preservation of anthocyanins than HAD. [ABSTRACT FROM AUTHOR]

The physicochemical and functional properties of covalently modified whey protein isolate (WPI) by (−)-epigallocatechin-3-gallate (EGCG) were investigated. WPI was chemically modified by EGCG under alkaline conditions. The effect of modification on foaming and emulsifying properties was evaluated. The results of SDS-PAGE and size exclusion chromatography indicated that modification by EGCG induced cross-linking on proteins of WPI. Fourier transform infrared spectroscopy (FT-IR) analysis illustrated the incorporation of phenolic groups into the modified WPI and the changes in protein secondary structure. Intrinsic fluorescence spectra revealed that modified WPI had a more compact tertiary structure compared to unmodified WPI. The modified WPI exhibited better foaming and emulsifying properties than unmodified WPI. These results suggest that EGCG modification is a potential method for improving the functional properties of WPI. [ABSTRACT FROM AUTHOR]

The subcritical dimethyl ether extraction (SDEE) was applied in the preparation of liver protein powder (LPD) in this paper. As expected, the lipids and water in tuna liver were co-removed by SDEE, and LPD with a high protein content could be obtained. Besides that, the maximal protein content (88.51%) of LPD was obtained by optimized extraction conditions (liquid-solid ratio 34 mL/g, time 70 min and stirring speed 945 rpm). Furthermore, the traditional preparation technique, pH-shift, was used for comparisons. Compared with pH-shift, the higher quality LPD could by obtain by SDEE with slight fishy and excellent yield, because of SDEE could prevent the loss of nutrition constituents and remove more flavor-active components. Moreover, the functional properties of prepared LPDs were compared with soybean protein powder (SPD) and egg white powder (EWP). The results showed that the LPD prepared by SDEE possessed the greater capacities in foaming, foam stability and fat absorption. Therefore, SDEE, with the advantages of no freeze-drying procedure and relatively low pressure, would be a better alternative to prepare high-quality protein powder in the food industry. • Application of subcritical dimethyl ether in the preparation of liver protein powder. • Response surface methodology was used for optimization of preparation conditions. • The powder with a high protein content could be obtained from high-mositure liver within 70 min. • The nutritional value and functional properties of prepared protein powder were desirable. • This method is more convenient and affordable than pH-shift method. [ABSTRACT FROM AUTHOR]