Nutritional and Digestive Properties of Protein Isolates Extracted from the Muscle of the Common Carp Using pH-Shift Processing

Abstract

This study details the nutritional and digestive properties of protein isolates that are extracted from carp (Cyprinus Carpio L.) muscle using pH shifting methods. Alkaline (ALPI) and acid (ACPI) protein isolates exhibit higher protein yields (87.6%, 76.3%, respectively). In addition to the high recovery of myofibrillar protein, a portion of the water‐soluble proteins is also recovered. The moisture contents of ACPI and ALPI are 85.5% and 88.5%, respectively, and the crude protein contents of these two fractions are 83.20% and 83.0%, respectively, both contents of which are higher than those for fresh muscle. Most part of the ash and fat are removed in the separation process. The protein isolation is also found to be lighter and whiter than the fresh muscle and there is no difference between amino acid content of protein isolation and that of fresh muscle. The maximum solubility of water washed surimi is 73.21%, while solubility of ACPI‐2 and ALPI‐2 (pH 7.0) are 66.67% and 62.08%, respectively. The digestibility of ALPI and ACPI is improved after being treated with chymotrypsin, which is about 7–8 times as that of fresh muscle. The results indicate that the protein isolates have better nutritional and digestive properties than the fresh muscle does in food processing.Practical ApplicationsCommon carp is a lower additional value fish that exists in large amount in China. This study investigates nutritional and digestive properties of protein from carp extracted by pH shifting methods. According to the obtained data in this study, pH shifting method is a good protein recovery method that can effectively remove bone spurs, skin, fat and other impurities. In addition, sarcoplasmic proteins can also be recovered. The nutritional properties of protein isolates of carp were suitable for supplementing as an ingredient for human consumption. The pH‐shift process greatly improves the protein digestibility. Therefore, there are broad application prospects of the protein isolation as protein ingredients in food industry.

Functional properties and dynamic rheology of protein isolates extracted from male and female common carp (Cyprinus carpio) muscle subjected to pH‐shifting method

“…The statistical analysis revealed nonsignificant difference in PC due to preparation method and gender. However, the results of present study demonstrated higher PC in the protein isolates (BPI and API) than raw muscle which were consistent with the results reported by Tian et al () and Panpipat and Chaijan, (). AC was of 9.54%, 4.83%, and 6.68%, respectively, for RM, BPIs, and APIs of male common carp against 9.13%, 4.37%, and 5.45%, respectively for female was observed.…”

“…The recovered proteins showed good color and superior functional characteristics and generally considered as safe for human consumption. Therefore, popularity of pH‐shifting method for the isolation of fish proteins is increasing now a days (Tian et al, ). The pH‐shift method includes two types of methods for the separation of muscular lipid‐free proteins from different fish species.…”

“…of pH-shifting method for the isolation of fish proteins is increasing now a days (Tian et al, 2017). The pH-shift method includes two types of methods for the separation of muscular lipid-free proteins from different fish species.…”

Effect of organic acid on recovery yields and characteristics of rohu (Labeo rohita) protein isolates extracted using pH shift processing

“…Shabanpour et al 21 reported that the protein recovery yields of silver carp and common carp during acidic and alkaline extraction were found to be 645.0 and 808.9 g kg −1 , 702.0 and 751.8 g kg −1 , respectively. The results found in this study were in agreement with the previous findings reported by Tian et al 22 and Vareltzis and Undeland 23 during the studies on common carp and blue mussel proteins.…”

Functional properties of gonad protein isolates from three species of sea urchin: a comparative study

“…Tian et al. (2017) have indicated that surimi from common carp has more water solubility amino acids owing to the acidic/alkaline solubilization process. As regard to isoleucine and leucine, the content of these two amino acids is enhanced after ISP processing (Sun et al., 2013), which was in accordance with our results.…”