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Functional properties of gonad protein isolates from three species of sea urchin: a comparative study
Author(s) -
Shang WenHui,
Yan JiaNan,
Du YiNan,
Cui XiaoFan,
Su ShengYi,
Han JiaRun,
Xu YunSheng,
Xue ChangFeng,
Zhang TieTao,
Wu HaiTao,
Zhu BeiWei
Publication year - 2020
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 - 10.1111/1750-3841.15464
Subject(s) - sea urchin , isoelectric point , gonad , biology , polyacrylamide gel electrophoresis , denaturation (fissile materials) , hemicentrotus , solubility , disulfide bond , amino acid , biochemistry , gel electrophoresis , paracentrotus lividus , chemistry , anatomy , enzyme , microbiology and biotechnology , nuclear chemistry , organic chemistry
Sea urchin Mesocentrotus nudus , Glyptocidaris crenularis , and Strongylocentrotus intermedius gonad protein isolates (mnGPIs, gcGPIs, and siGPIs) were extracted by isoelectric solubilization/precipitation (ISP) from the defatted gonads, and their functional properties were compared. Sodium dodecyl sulfate polyacrylamide gel electrophoresis results showed the similar protein pattern between each protein isolate and defatted gonad, indicating the high efficiency of ISP processing for protein recovery. Amino acid profileconfirmed that the mnGPIs and siGPIs could be potential sources of essential amino acid in nature. As regard to functional properties, mnGPIs showed higher water ‐ and oil ‐ holding capacities followed bysiGPIs and gcGPIs and all protein isolates presented great foaming property. As for emulsifying activity index (EAI), mnGPIs, gcGPIs, and siGPIs showed the minimum solubility and EAI at pH 5, 3, and 4, respectively, and behaved a pH‐dependent manner. The gcGPIs revealed the highest EAI from pH 6 to 8 among the samples. In addition, circular dichroism showed increased content of β‐sheet at the expense of α‐helix and β‐turn, suggesting the structure denaturation of the protein isolates. Indeed, no statistical difference was observed between secondary structure of mnGPIs and siGPIs. Moreover, ISP processing increased free sulfhydryl content of sea urchin protein isolates, but no difference was observed among the samples. Furthermore, siGPIs revealed the highest amount of total sulfhydryl and disulfide bonds, whereas both defatted gonads and protein isolates from G. crenularis presented the maximum surface hydrophobicity. These results suggest that gonad protein isolates from three species of sea urchin possess various functionalities and therefore can be potentially applied in food system. Practical Application Sea urchin M. nudus , G. crenularis , and S. intermedius gonads are edible, whereas the functional properties of protein isolates from sea urchin gonad remain unknown. In this case, the extraction and comparison of three species of sea urchin gonad protein isolates will not only confirm functional properties but also screen food ingredients with suitable functions. In this study, functionalities of protein isolates derived from M. nudus , G. crenularis , and S. intermedius gonads would provide potential application in bakery food and meat products or as emulsifier candidates in food system.