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Showing 3 results for Ph-Shif

Masoud Rezaei, , ,
Volume 4, Issue 3 (12-2015)
Abstract

The present study was conducted to evaluate the efficacy of the pH-shift process in protein recovery from whole and gutted common kilka and characteristics of the produced gel compared with muscle surimi obtained with the conventional method. Although both acidic and alkaline methods reduced total pigment (TP) in isolates obtained from the whole and gutted fish, the alkaline version was more effective and the lowest amount of TP was observed in the isolate from gutted fish using alkaline version. The last sample also contained the lowest amount of TCA soluble peptide which was significantly lower than the others. Also, gel produced from the isolate recovered form gutted kilka with the alkaline version had significantly higher water holding capacity and gel hardness but it was weaker than the sample obtained with conventional method. The results were supported with higher relative amount of actomyosin and actin in the structure of the gels produced from the gutted fish isolate and surimi from fish muscle, as reflected in SDS-PAGE. Nevertheless, the whiteness of the samples recovered with pH-shift process was quite lower than the muscle surimi which reveals the necessity of more research in this area.    
Mina Esmaeili Kharyeki, Shima Mansouri Moghadam,
Volume 11, Issue 4 (12-2022)
Abstract

The present study was conducted with the aim of protein isolate production from the muscle of grass carp (Ctenopharyngodon idella) and investigation of the effect of extraction pH on different properties of isolated protein. Proteins were produced by pH-shift method in two treatments including dissolution in alkaline pH (11.5), and acidic pH (3), and then evaluated in terms of nutritional value, functional properties, and structural changes. According to the results, the yield of protein production was significantly higher in alkaline conditions than in acidic conditions. The evaluation of emulsifying and foaming capacity and water absorption capacity showed that the protein obtained from alkaline pH was better than acidic treatment. Also, the extracted proteins contained all essential amino acids within the recommended limit for daily consumption of adults. The evaluation of color indices showed that the protein obtained from acidic pH had a brighter and whiter color than alkaline pH. The images obtained from the scanning electron microscope and the FTIR spectra of samples showed that the pH-shift method did not lead to extensive destruction of the protein structure and both protein isolates had all the absorption peaks related to the main bonds of the proteins structure. In general, it can be concluded that the pH-shift method is an efficient method for extracting high quality protein from grass carp tissue, and different alkaline and acidic conditions lead to the production of proteins with different characteristics that can be used based on the application that is intended for the final product.

 
Seyed Vali Hosseini, Mohaddeseh Pir Alidehi, Mohammad Ali Nematollahi , Fezzeh Aryanasab,
Volume 14, Issue 1 (2-2025)
Abstract

Fish protein, with its higher levels of essential amino acids than land animal protein, high digestibility, and strong binding ability with other proteins as a binder, emulsifier, or dispersing agent, has prompted food industry experts to conduct extensive research into various methods for producing concentrates and powders from it. In this research, protein powder was produced from silver carp meat (Hypophthalmichthys molitrix) by washing, heat and pH-shift methods, and then the amino acid composition of the protein powder produced by different methods was compared. The results of the comparison of the average of the amino acid composition indicated that heating treatment has the maximum amount of 306.08, 409.09 mg/g of protein and 75.0% of total essential and non-essential amino acids and EAA/NEAA ratio, respectively (p<0.05). and the minimum values ​​in the EAA and NEAA indices in the pH-shift treatment with the average values ​​of 229.39 and 321.08 mg/g of protein, respectively (p<0.05) Also, the minimum ratio of EAA/NEAA was assigned to the washing treatment with an average value of 0.68% (p<0.05). On the other hand, according to the general results and in line with determining and classifying the optimal treatment, it can be reported that heat treatment among other treatments, Due to the maximum amounts of total essential and non-essential amino acids and the EAA/NEAA ratio and the amount of Glu and Asp amino acids (two important umami amino acids),


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