Obtaining reduced-salt restructured white tuna (Thunnus alalunga) mediated by microbial transglutaminase

Effect of citric acid on physicochemical properties and protein structure of low-salt restructured tilapia (Oreochromis mossambicus) meat products

BACKGROUND

The growing consumer demand for healthy products has encouraged the development of low-salt meat products. In this study, to develop low-salt restructured tilapia (Oreochromis mossambicus) meat products, citric acid was used to improve the properties of restructured tilapia products.

RESULTS

In comparison with control restructured fish products (RP) and surimi products (SP), 0.2% citric acid-treated restructured fish products (RPC) and surimi products (SPC) showed a significant decrease in expressible water and water activity and a remarkable increase in whiteness, dry matter, hardness, chewiness, gumminess, and acceptability. Mechanistic studies suggested that citric acid significantly changed the content of total protein and myofibrillar proteins and promoted degradation of heavy myosin chains. Fourier-transform infrared and Raman spectra revealed the citric acid-mediated alteration in the peak intensities of amide I and amide II bands, which changed the secondary structures of RPC and SPC.

CONCLUSION

It is feasible to prepare low-salt restructured tilapia meat products using citric acid, which offers a means of using muscle by-products and exploiting new functional products with an added commercial value. © 2020 Society of Chemical Industry.

Sensory evaluation of low-fat yoghurt produced with microbial transglutaminase and comparison with physicochemical evaluation

BACKGROUND

Low-fat or non-fat yoghurts are popular nowadays. However, their texture is not good and they show considerable syneresis with time. The aim of this research was to evaluate the effect of the application of transglutaminase (TG) to low-fat yoghurt to determine if similar sensory properties to those of full-fat yoghurt can be obtained. Methods of adding TG (prior or simultaneous with fermentation), dose, and TG origin were evaluated. Correlations between sensory and physicochemical parameters were assessed.

RESULTS

The results showed no significant differences between TG addition methods in terms of the quantitative and qualitative sensory attributes studied. Simultaneous addition of TG was preferred to speed up the process. A dose of 1 U g^-1 was selected as optimal. Few differences were detected due to the origin of the TG. They were not significant although some differences were observed in terms of density, bitterness, and syneresis compared with low and full-fat yoghurts.

CONCLUSION

The results showed that sensory parameters cannot be associated with only one physicochemical parameter in yoghurt evaluation. Transglutaminase can be used as a substitute for stabilizers in the production of low-fat yoghurt, maintaining good sensory properties and avoiding initial syneresis. © 2018 Society of Chemical Industry.