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Structural characterization and functional properties of CNPP, a byproduct formed during CPP preparation
Author(s) -
Ren Likun,
Guo Qingqi,
Yang Yang,
Liu Xiaofei,
Guan Huanan,
Chen Fenglian,
Bian Xin,
Zhang Xiumin,
Zhang Na
Publication year - 2021
Publication title -
journal of food science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.772
H-Index - 150
eISSN - 1750-3841
pISSN - 0022-1147
DOI - 10.1111/1750-3841.15717
Subject(s) - casein , ingredient , chemistry , functional food , whey protein , solubility , soy protein , hydrolysis , food science , fourier transform infrared spectroscopy , phosphopeptide , chromatography , biochemistry , chemical engineering , organic chemistry , phosphorylation , engineering
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.