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Ren LK, Guo QQ, Yang Y, Liu XF, Guan HN, Chen FL, Bian X, Zhang XM, Zhang N. Structural characterization and functional properties of CNPP, a byproduct formed during CPP preparation. J Food Sci 2021; 86:1845-1860. [PMID: 33908034 DOI: 10.1111/1750-3841.15717] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2020] [Revised: 02/03/2021] [Accepted: 03/06/2021] [Indexed: 11/29/2022]
Abstract
Casein nonphosphopeptide (CNPP), a byproduct formed during the preparation of casein phosphopeptide (CPP), is often discarded on a large scale. Although our previous studies have demonstrated the ameliorative effect of CNPP on muscle wasting disorders, its structure-function mechanism is still unclear. Therefore, considering the great influence of structural characteristics on function, this study aims to explain the potential mechanism by characterizing the physicochemical and functional properties of CNPP. The results of structural characterization indicated that CNPP was of low molecular weight and composed of the complete range of amino acids; it was particularly rich in leucine. Compared with casein, CNPP had a lower molecular size and total/free sulfhydryl content (reduced 2.44 and 2.02 µmol/g in CNPP, respectively). Additionally, Fourier transform infrared spectroscopic analysis revealed that enzymatic hydrolysis caused protein unfolding, and the content of β-turns and random coils reached 50.20% and 10.67%, respectively. Fluorescence-dependent detection of CNPP indicated a reduction of spectral intensity and the occurrence of a red shift. The changes in the structure of CNPP significantly affected its functional characteristics. CNPP has better solubility, foaming, and digestion properties than those of casein and whey protein. Specifically, the foam stability and emulsification properties decreased in the order of casein > CNPP > whey protein. The present study can provide a substantial basis for future application of CNPP as a functional ingredient against sarcopenia.
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Affiliation(s)
- Li-Kun Ren
- Key Laboratory of Food Science and Engineering of Heilongjiang Province, College of Food Engineering, Harbin University of Commerce, Harbin, China
| | - Qing-Qi Guo
- School of Forestry, Northeast Forestry University, Harbin, China
| | - Yang Yang
- Key Laboratory of Food Science and Engineering of Heilongjiang Province, College of Food Engineering, Harbin University of Commerce, Harbin, China
| | - Xiao-Fei Liu
- Key Laboratory of Food Science and Engineering of Heilongjiang Province, College of Food Engineering, Harbin University of Commerce, Harbin, China
| | - Hua-Nan Guan
- Key Laboratory of Food Science and Engineering of Heilongjiang Province, College of Food Engineering, Harbin University of Commerce, Harbin, China
| | - Feng-Lian Chen
- Key Laboratory of Food Science and Engineering of Heilongjiang Province, College of Food Engineering, Harbin University of Commerce, Harbin, China
| | - Xin Bian
- Key Laboratory of Food Science and Engineering of Heilongjiang Province, College of Food Engineering, Harbin University of Commerce, Harbin, China
| | | | - Na Zhang
- Key Laboratory of Food Science and Engineering of Heilongjiang Province, College of Food Engineering, Harbin University of Commerce, Harbin, China
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Tan L, Hong P, Yang P, Zhou C, Xiao D, Zhong T. Correlation Between the Water Solubility and Secondary Structure of Tilapia-Soybean Protein Co-Precipitates. Molecules 2019; 24:molecules24234337. [PMID: 31783603 PMCID: PMC6930460 DOI: 10.3390/molecules24234337] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2019] [Revised: 11/16/2019] [Accepted: 11/26/2019] [Indexed: 11/16/2022] Open
Abstract
The secondary structure of a protein has been identified to be a crucial indicator that governs its water solubility. Tilapia protein isolate (TPI), soybean protein isolate (SPI), and tilapia-soybean protein co-precipitates (TSPC3:1, TSPC2:1, TSPC1:1, TSPC1:2, and TSPC1:3) were prepared by mixing tilapia meat and soybean meal at different mass ratios. The results demonstrated that the water solubility of TSPCs was significantly greater than that of TPI (p <0.05). The changes in ultraviolet–visible and near-ultraviolet circular dichroism spectra indicated that the local structure of TSPCs was different from that of TPI and SPI. Fourier transform infrared Spectroscopy revealed the co-existence of TPI and SPI structures in TSPCs. The secondary structures of TSPCs were predominantly α-helix and β-sheet. TSPC1:1 was unique compared to the other TSPCs. In addition, there was a good correlation between the water solubility and secondary structure of TSPCs, in which the correlation coefficients of α-helix and β-sheet were −0.964 (p <0.01) and 0.743, respectively. TSPCs displayed lower α-helix contents and higher β-sheet contents compared to TPI, which resulted in a significant increase in their water solubility. Our findings could provide insight into the structure–function relationship of food proteins, thus creating more opportunities to develop innovative applications for mixed proteins.
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Affiliation(s)
- Li Tan
- College of Food Science and Technology, Guangdong Ocean University, Zhanjiang 524088, China; (L.T.); (P.H.); (P.Y.); (D.X.); (T.Z.)
- Guangdong Provincial Key Laboratory of Aquatic Product Processing and Safety, Zhanjiang 524088, China
- Guangdong Provincial Engineering Technology Research Center of Marine Food, Zhanjiang 524088, China
- Guangdong Provincial Modern Agricultural Science and Technology Innovation Center, Zhanjiang 524088, China
| | - Pengzhi Hong
- College of Food Science and Technology, Guangdong Ocean University, Zhanjiang 524088, China; (L.T.); (P.H.); (P.Y.); (D.X.); (T.Z.)
- Guangdong Provincial Key Laboratory of Aquatic Product Processing and Safety, Zhanjiang 524088, China
- Guangdong Provincial Engineering Technology Research Center of Marine Food, Zhanjiang 524088, China
- Guangdong Provincial Modern Agricultural Science and Technology Innovation Center, Zhanjiang 524088, China
- Southern Marine Science and Engineering Guangdong Laboratory (Zhanjiang), Zhanjiang 524088, China
| | - Ping Yang
- College of Food Science and Technology, Guangdong Ocean University, Zhanjiang 524088, China; (L.T.); (P.H.); (P.Y.); (D.X.); (T.Z.)
- Guangdong Provincial Key Laboratory of Aquatic Product Processing and Safety, Zhanjiang 524088, China
- Guangdong Provincial Engineering Technology Research Center of Marine Food, Zhanjiang 524088, China
- Guangdong Provincial Modern Agricultural Science and Technology Innovation Center, Zhanjiang 524088, China
| | - Chunxia Zhou
- College of Food Science and Technology, Guangdong Ocean University, Zhanjiang 524088, China; (L.T.); (P.H.); (P.Y.); (D.X.); (T.Z.)
- Guangdong Provincial Key Laboratory of Aquatic Product Processing and Safety, Zhanjiang 524088, China
- Guangdong Provincial Engineering Technology Research Center of Marine Food, Zhanjiang 524088, China
- Guangdong Provincial Modern Agricultural Science and Technology Innovation Center, Zhanjiang 524088, China
- Southern Marine Science and Engineering Guangdong Laboratory (Zhanjiang), Zhanjiang 524088, China
- Correspondence: ; Tel.: +86‐13828262885
| | - Dinghao Xiao
- College of Food Science and Technology, Guangdong Ocean University, Zhanjiang 524088, China; (L.T.); (P.H.); (P.Y.); (D.X.); (T.Z.)
- Guangdong Provincial Key Laboratory of Aquatic Product Processing and Safety, Zhanjiang 524088, China
- Guangdong Provincial Engineering Technology Research Center of Marine Food, Zhanjiang 524088, China
- Guangdong Provincial Modern Agricultural Science and Technology Innovation Center, Zhanjiang 524088, China
| | - Tanjun Zhong
- College of Food Science and Technology, Guangdong Ocean University, Zhanjiang 524088, China; (L.T.); (P.H.); (P.Y.); (D.X.); (T.Z.)
- Guangdong Provincial Key Laboratory of Aquatic Product Processing and Safety, Zhanjiang 524088, China
- Guangdong Provincial Engineering Technology Research Center of Marine Food, Zhanjiang 524088, China
- Guangdong Provincial Modern Agricultural Science and Technology Innovation Center, Zhanjiang 524088, China
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