Physicochemical and functional properties of protein isolate recovered from Rana chensinensis ovum based on different drying techniques

Waste Utilization: Physicochemical characteristics, stability and applications of emulsified Rana chensinensis ovum oil with waste extracts

“…The proportion of essential amino acids in the total amino acids is much higher than the recommended value of FAO (36 %) ( FAO/WHO/UNU, 1985 ). Meanwhile, the content of sulfur-containing amino acids in RCOPI is more than 3.34 g/100 g, which is much higher than that of most plant proteins ( Li et al, 2022 ). RCOPI is expected to be an ideal source of sulfur-containing amino acids, compared with many plant proteins.…”

“…The waste residues were rich in proteins, accounting for more than 50 %, which was much higher than most typical high protein foods such as poultry (25 %), fish (20 %), and eggs (15 %). An alkali-solution and acid-isolation method was applied to extract the proteins in those waste ( Gan et al, 2020 , Li et al, 2022 ). The average isolation yield of RCOPI was 27 %.…”

“…However, RCOO is susceptible to oxidative rancidity, which limits its application in food industry. On the other hand, our previous study showed that the protein isolates recovered from Rana chensinensis ovum has great potential as a cheap and sustainable protein source in food applications ( Li et al, 2022 ; Zhang et al, 2022 ). Rana chensinensis ovum protein isolates (RCOPI) not only have high nutrition, but also show outstanding functional properties such as water retention, oil retention, foaming ability, inhibition of linoleic acid oxidation and other aspects, making it a potential emulsified food protectant ( Li et al, 2022 , Zhang et al, 2022 ).…”

Effects of Drying Methods on the Physicochemical and Functional Properties of Cinnamomum camphora Seed Kernel Protein Isolate

“…However, the morphology of VD-CPI comprised randomly crushed stone particles (V1, 200×), and that of SD-CPI comprised finely crumpled spheroid particles (S1, 200×). VD-CPI showed a thick and dense lumpy structure (V2, 1000×), which may be caused by the layering of solutes and solvents during a long heating and drying process, with proteins gradually settling to the bottom of the container while water was transferred from the interior of the sample to the surface and rapidly evaporated [ 23 ]. The microstructure of SD-CPI was spherical and pleated (S3, 5000×), which may be related to the characteristics of spray-drying.…”

“…This phenomenon may be due to the partially aggregation and cross-linking of CPI subjected to the VD process, as confirmed by the results for the -SH group contents ( Table 3 ) and SDS-PAGE profiles ( Figure 3 ). In a study of the Rana chensinensis ovum protein isolate, Li et al (2022) [ 23 ] observed similar fluorescence intensities in FD and SD proteins, whereas the protein subjected to VD showed a significant decrease in fluorescence intensity. In addition, the sequential increase in the maximum emission wavelengths (λ max ) for VD-CPI (321.0 nm), SD-CPI (324.8 nm), and FD-CPI (326.0 nm) indicated that the tryptophan residues were exposed to a more hydrophilic environment, facilitating their interaction with ANS.…”