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.

Effect of garlic extract on physical, oxidative and microbial changes during refrigerated storage of restructured product from Thai pangas (pangasianodon hypophthalmus) surimi.

The effect of garlic's aqueous extract (GAE) during refrigerated storage of the restructured products from Pangasius (Pangasianodon hypophthalmus) was evaluated. Protein and lipid oxidation, protein pattern on SDS-PAGE, TPC as well as WHC, gelling properties, texture profiles and whiteness of the surimi gel was evaluated periodically during a refrigerated storage period of 20 days. Increase of water holding capacity in GAE added gels indicated stronger protein network formation, whereas, decrease of protein solubility suggested formation of protein aggregates during gelation process. Lipid oxidation decreased in treated samples but the rate of increase varied, depending upon the concentration of GAE. Protein carbonyl content increased during storage, but slow increase in treated samples. Gel strength in treated samples increased and accompanied by thickening of myofibrillar head chain. Hardness, adhesiveness and gumminess parameters affected most due to addition of GAE. Sensory analysis revealed that the RP with 1 % GAE preferred most and control was acceptable upto 12 days.

Restructured fish product from white croacker (Micropogonias furnieri) mince using microbial transglutaminas

This study aimed at determining the influence of three concentrations of commercial transglutaminase enzyme in restructured fillet of minced fish from white croacker (Micropogonias furnieri), one of the four marine species with notability in Brazil. The restructured fillet developed had advantages when compared to traditional fillet, such as absence of spine and less flavour intensity (washes cycles). Washing process for white croacker mince was compared with five clarification agents: water (control), phosphoric acid (H3PO4), sodium chloride (NaCl), calcium carbonate (CaCO3) and sodium bicarbonate (NaHCO3). The higher quality product (whiteness) was obtained with calcium carbonate washes. Three concentrations (1.5, 1.0 and 0.5 percent) of microbial transglutaminase MGTase (Active TG-B percentv/v and Active TG-BP percentw/w) were compared, in order to produce fish restructured product (boneless fillet). The concentration of 1.5 percent (both enzymes), produced better results. The restructured products were compared by sensory analysis and showed better sensory parameters (appearance, odour, flavour and texture) samples treated with Active TG-B (solution form).

Este estudo teve como objetivo determinar a influência de três concentrações de enzima transglutaminase comercial em filés reestruturado a partir de polpa de corvina (Micropogonias furnieri), uma das quatro espécies marinhas notáveis no Brasil. O filé reestruturado desenvolvido tem vantagens quando comparado aos filés tradicionais, tais como, a ausência da espinhas e sabor menos intenso (ciclos de lavagens). O processo de lavagem da polpa de corvina foi comparado com cinco agentes clarificantes: água (controle), ácido fosfórico (H3PO4), cloreto de sódio (NaCl), carbonato de cálcio (CaCO3) e bicarbonato de sódio (NaHCO3). O produto de qualidade superior (mais branco) foi obtido com a lavagem com carbonato de cálcio. Três concentrações (1,5 por cento, 1,0 por cento e 0,5 por cento) de transglutaminase microbiana (Activa TG-B por cento v/v e Activa TG-BP por cento p/p) foram comparadas a fim de produzir o produto reestruturado (filé sem espinha). A concentração de 1,5 por cento (ambas as enzimas) produziu melhores resultados. Os produtos reestruturados foram comparados através de análise sensorial, e apresentaram melhores parâmetros sensoriais (aparência, odor, sabor e textura), as amostras tratadas com Activa TG-B (forma de solução).