FOOD SCIENCE ›› 2019, Vol. 40 ›› Issue (12): 22-29.doi: 10.7506/spkx1002-6630-20180626-484

• Food Chemistry • Previous Articles     Next Articles

Gelation and Digestive Properties of Blue Round Scads (Decapterus maruadsi) Protein Recovered by Acidic/Alkaline Isoelectric Solubilization/Precipitation

SUN Lechang1,2,3, LIN Yichen1, LIU Weifeng1, WENG Ling1,2,3, ZHANG Lingjing1,2,3, LIU Guangming1,2,3, CAO Minjie1,2,3,*   

  1. 1. College of Food and Biological Engineering, Jimei University, Xiamen 361021, China; 2. National & Local Joint Engineering Research Center of Deep Processing Technology for Aquatic Products, Xiamen 361021, China; 3. Fujian Provincial Engineering Technology Research Center of Marine Functional Food, Xiamen 361021, China
  • Online:2019-06-25 Published:2019-06-28

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Abstract: In the present study, protein isolates were recovered from the muscle of blue round scads (Decapterus maruadsi) using acidic- or alkaline-aided isoelectric solubilization/precipitation. The physiochemical, gelation, and digestive properties of acid (API)- and alkali (KPI)-recovered proteins were investigated, as compared to total proteins (TP) and myofibrillar proteins (MP). D. maruadsi muscle proteins were even more soluble in alkali than in acid. The recovery yield (65.0% and 84.6%, respectively) of API and KPI were much higher as compared with MP (54.0%). API, KPI and MP contained far smaller amounts of lipid and ash, whereas KPI contained the highest protein content. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) analysis showed that there were no significant differences in the protein composition of TP, KPI and API. However, compared with TP, API and KPI had lower contents of Gly and Pro. Textural and rheological analysis revealed that API and KPI possessed lower gel strength and storage module G’ than TP and MP. Meanwhile, although no significant changes occurred in API, remarkable decreases in the G’ values of TP, MP and KPI were observed in the temperature range from 50 to 55 ℃, indicating the occurrence of modori phenomenon. This finding was well consistent with the microstructure observed by scanning electron microscopy (SEM), whereas KPI, TP and MP showed looser, porous and disorganized network when incubated at 55 ℃ for 30 min than at 90 ℃. The results of simulated gastrointestinal digestion showed that MP had the best digestibility among four proteins, while KPI and API possessed better digestibility than TP. In conclusion, ISP can greatly improve the recovery yield of protein from blue round scads. Due to their higher digestibility and poorer gelation ability, the use of the protein isolates as protein ingredients in food products is proposed.

Key words: blue round scads, acidic/alkaline isoelectric solubilization/precipitation, gelation properties, digestive properties

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