Testing caffeic acid as a natural antioxidant in functional fish-fibre restructured products

7 páginas, 4 figuras, 5 tablasThe antioxidant effectiveness of caffeic acid addition to minced fish muscle with or without wheat dietary fibre added was studied. Wheat dietary fibre showed a significant prooxidant effect on minced fish muscle during chilled storage that was significantly inhibited in presence of 100 mg/kg caffeic acid. In samples containing caffeic acid and wheat dietary fibre, lipid oxidation was completely inhibited after 10 days. Results obtained from the instrumental texture profile analysis showed that the inclusion of wheat dietary fibre with or without caffeic acid lowered the texture profile analysis parameters. Caffeic acid did not render any changes on the water binding capacity. These results prove that caffeic acid can be successfully used as a natural antioxidant in wheat dietary fibre minced fish restructured products.This work was performed within the Integrated Research Project SEAFOODplus, contract No FOOD-CT-2004-506359 and the research project AGL2006-26016-E/GAN. The [partial] financing of this work by the European Union and the Spanish Ministerio de Educación y Ciencia is gratefully acknowledged.Peer reviewe

Functional insights into the infective larval stage of Anisakis simplex s.s., Anisakis pegreffii and their hybrids based on gene expression patterns

List of species and specimen used in the phylogenetic tree of Additional file 1. Code of the voucher specimen and accession number for mitochondrial gene COII (*: sequences obtained from GenBank). Labeled are the specimens selected for RNA sequencing (first number, population; second number specimen). A. simplex s.s. – A. pegreffii refers to hybrids haplotype according Abollo et al. [23]. (DOCX 47 kb

Prediction of frozen storage time of Cape hake (Merluccius capensis and Merluccius paradoxus) by instrumental methods

An instrumental method to predict frozen storage time of Cape hake was developed by evaluation of a combination of methods previously known to classify hake into different quality categories, such as apparent viscosity, Kramer and puncture tests. The results showed that with multiple linear regression analysis it was possible to obtain linear models for the prediction of storage time at -20°C. Only apparent viscosity (ηapp) and Kramer shear resistance (Kramer) were included in the regression model (months = 15.003 - 0.001ηapp + 0.144 Kramer; Radj 2 = 0.91). The model had a typical error of estimation of 2.0 months. The simplicity of the model, which requires only two parameters, and the easiness of their measurement make the method a good candidate for use in quality control laboratories of hake processing industries. © 2006 Society of Chemical Industry.Peer Reviewe

Stress-relaxation test to evaluate textural quality of frozen stored Cape hake (M. capensis and M. paradoxus)

A stress-relaxation test was developed for frozen stored Cape hake (M. capensis and M. paradoxus) to be used as a quality assessment tool. Fish was compressed by 5% and deformation was kept constant for 60 s. The resulting relaxation curves were fitted to different multiexponential regression models. A three-term exponential fit without a residual term was chosen as the best model. Relaxation parameters from this test correlated well with sensory texture attributes derived from the quality index method (QIM). The high degree of correlation (0.90) suggests that these relaxation parameters could be used as markers for evaluating textural quality of frozen Cape hake, replacing sensory assessment. The regression model was: STA = 0.117 + 0.967 RP (where STA = PC1 from sensory texture attributes and RP = PC1 from relaxation parameters), with P < 0.001. © 2004 Elsevier Ltd. All rights reserved.Peer Reviewe

Effect of prolactin and glucocorticoids on P-enolpyruvate carboxykinase activity in liver and mammary gland from diabetic and lactating rats

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Hake natural actomyosin interaction with free fatty acids during frozen storage

The interaction of hake muscle actomyosin with free fatty acids in 0.6 M KCl pH 7 during frozen storage has been studied up to 280 days. ATPase activity, protein solubility and relative viscosity measurements were performed. Oleic and myristic acid had a detrimental effect on these properties during frozen storage. Oleic acid was bound to the protein from the beginning, mainly to the insoluble fraction. The diminishment of functionality following addition of oleic acid is not due to aggregation caused by covalent-type bonds, since it occurs well before the electrophoretic change is appreciablePeer Reviewe

Raman Spectroscopic Study of Structural Changes in Hake (Merluccius merluccius L.) Muscle Proteins during Frozen Storage

This paper examines changes in the structure and functionality of fish muscle proteins at frozen storage temperatures known to render very different practical storage lives (-10 and -30 °C). Apparent viscosity and dimethylamine (DMA) content showed drastic temperature-related differences during storage. Raman spectroscopy revealed the occurrence of some structural changes involving secondary and tertiary protein structures. The changes in secondary structure were quantified, showing an increase of β-sheet at the expense of α-helix structure. The νC-H stretching band near 2935 cm-1 increased in intensity, indicating denaturation of the muscle proteins through the exposure of aliphatic hydrophobic groups to the solvent. These structural changes were more pronounced at -10 °C but occurred at both storage temperatures, whereas changes in apparent viscosity and DMA only occurred in storage at -10 °C. The possible utility of these structural changes for quality assessment is discussed.Peer Reviewe

Quality control of frozen fish using rheological techniques

This paper describes the mechanical/physical methods most commonly cited in the literature for measuring deterioration of frozen fish, examines the correlation of these methods with sensory analysis and discusses their possible utility for the quality control of frozen fish.Peer Reviewe

Instrumental Texture [Part III. Fish and Seafood Products]

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Stress relaxation test for monitoring post mortem textural changes of ice-stored cod (Gadus morhua L.)

The possibilities of using the stress relaxation test as a nondestructive method to monitor post-mortem textural changes of ice-stored cod have been evaluated. The stress relaxation tests were performed in gutted cod. Fish were compressed by 5% and deformation was kept constant for 60 s. The relaxation curves obtained were fitted to nonlinear and linear regression models. Nonlinear regressions with 2 or 3 exponential terms and the linear regression model could be fitted to the relaxation curve of ice-stored cod, although the three-terms exponential models gave the best results for assessing the quality of ice-stored cod (maximum relative difference ≤ 2% and R2 > 0.999). The highest differences were found between pre-rigor and in-rigor states.Peer Reviewe