Search

It has been documented that the shelf life of fishery products is extremely reduced due to microbial development and its endogenous biochemistry. For this reason, food technologists around the world are researching how to reduce the main processes that lead to spoilage. Recently, high-intensity ultrasound (HIU) has had different applications in the food industry because the cavitation effect can inhibit or reduce microbial development as well as cause conformational changes in muscle enzymes. Therefore, in this study, HIU was applied for 30, 60, and 90 min to the tilapia (Oreochromis niloticus) fillet, and subsequently, it was stored on ice for 20 days. During this period, samples were taken every 5 days (day 0, 5, 10, 15, and 20), and moisture content, pH, total volatile base (TVB-N), non-protein nitrogen (NPN), texture, electrophoresis, color, and microbiological analyses (mesophiles and psychrophiles) were determined. No significant changes (p ≥ 0.05) were observed in the moisture content, pH, and the L* parameter, while a significant decrease (p < 0.05) in TVB-N (from 29.67 to 15.09), NPN (from 0.39 to 0.27%), and texture (from 4.88 to 2.69 N) were found. On the other hand, an increase (p < 0.05) in a* (from 2.02 to 4.27) and b* (from 10.66 to 12.45) parameters, as well as total mesophile count (from 2.48 to 6.52 log CFU/g) were detected due to the application of ultrasound. The results suggest that the application of this treatment represents a viable alternative to increase the shelf life and quality of tilapia fillets stored on ice. [ABSTRACT FROM AUTHOR]

Protein hydrolysates and peptides can show biological activities, and pulsed ultrasound improves bioactivities. Among matrices from which protein hydrolysates can be obtain, chickpea is an excellent source. The objective of this research was to evaluate the effect of pulsed ultrasound on globulin concentrate to obtain chickpea hydrolysate (HGb) and peptide fractions and their bioactivity. Antioxidant activity by ABTS (2,2′-Azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt), FRAP (Ferric Reducing Antioxidant Power) and human erythrocyte assays was determined. The electrophoretic profile, amino acid profile, and antimicrobial activity of hydrolysates were also determined. Two hydrolysates had the highest antioxidant activity: HGb (91.44% ABTS inhibition, 73.04% hemolysis inhibition and 5185.57 µmol TE/g dried sample in FRAP assay) and HGb-20 (48.25% ABTS inhibition, 100% hemolysis inhibition and 2188.53 µmol TE/g dried sample in FRAP assay). Peptide fractions inhibited 100% of the hemolysis on human erythrocytes. The hydrolysates from chickpea proteins obtained with savinase have antioxidant activity through the SET and HAT mechanisms. The application of the obtained compounds for the development of functional foods or for food preservation should be considered. [ABSTRACT FROM AUTHOR]

Summary: The bioactive properties of peptide fractions obtained from the hydrolysis of squid (Dosidicus gigas) by‐products collagen, using Protease type XIV and ultrafiltration (UFI), were studied. The basic objective was to improve the bioactivity of squid hydrolysates via the application of UFI. Peptide fractions obtained after UFI had higher antioxidant and antimutagenic activities, but the antiproliferative activity did not improve after UFI. Peptides <5 kDa (Fraction F3) showed higher antioxidant and antimutagenic activities, as well as lower antioxidant and antiproliferative activities than both, peptides >10 kDa (F1) and those within the range of >5 to <10 kDa (F2). Band at lower field observed in FT‐IR spectra and proton‐peaks observed at higher 1H‐NMR fields, both associated to aromatic amino acids, as well as to other antioxidant amino acids such as hydroxyproline, glycine, arginine and lysine, may explain F3 bioactivity. Ultrafiltration can, therefore, be used to improve some bioactivities of squid collagen hydrolysates. [ABSTRACT FROM AUTHOR]

Abstract: Jumbo squid (Dosidicus gigas) is an important commercialized fishery in Mexico; however, during its post‐catch processing, several physicochemical changes occur in flesh, which could result in texture modifications. In this research, changes in water‐holding capacity, protein solubility (PS), firmness, fibrils microstructure, and color of squid muscle (mantle, fins, and arms) during cooking (30 min at 100 °C) were evaluated. Throughout cooking were exhibited different shrinkage and weight loss behavior among three anatomical regions (p < .05). After cooking, PS of muscle from fins and arms remained similar, meanwhile, mantle muscle PS decreased 75%. Shear force (SF) magnitude order (p < .05) registered in fresh muscle was fins > arms > mantle, whereas at ending cooking, mantle muscle required the lowest SF. Microscopic analysis revealed a major quantity of collagen fibers in fins and arm muscle suggesting its possible relation to their hardness, in both fresh and cooked state. Practical applications: Jumbo squid (Dosidicus gigas) is an important marine resource in Mexico and many Asiatic and European countries. Its muscle (fins, arms, and mantle) edible items are commercialized and consumed in fresh, brined, and cooked presentations. Squid muscle protein structures (fibril and stromal) are organized different than fish as well as beef, pork and poultry; therefore its textural, physicochemical and sensorial (quality parameters) changes induced by cooking are distinctive. Squid meat acceptance by consumers is related mainly by texture than the taste or color attributes. Therefore, from economic point of view of domestic and large‐scale markets, the establishment of best cooking conditions of squid became essential. [ABSTRACT FROM AUTHOR]

Muscle from mantle, fins and arms of squid (Dosidicus gigas) were compared based on lysyl oxidase activity (LOX), chemical/structural and thermodynamic properties of highly cross-linked collagen. The arms collagen presented the highest temperature (Tp) and enthalpy of transition. The arms collagen thermic properties may be explained by the higher imino amino acid content, proline and lysine hydroxylation degrees. Moreover, among the regions, the collagen from the arms had a more intense β band chain, hydroxymerodesmosine peak in the resonance magnetic nuclear spectra and pyridinoline peak in the Raman spectra. Fins showed the highest LOX activity. The LOX activity was associated with the Tp, proline and lysine hydroxylation degrees. These results implied that the collagen in the arms was more intermolecularly ordered than the mantle and fins, and may provide a theoretical basis for a better understanding of the thermal behaviour of squid tissues during management and processing. [ABSTRACT FROM AUTHOR]

Connective tissue (CT) proteins in jumbo squid ( Dosidicus gigas) play an important role because they are the responsible for the union between various cells; hence, there is a close relationship between their functions and muscle firmness during ice storage. In this study, the thermal resistance and solubility of the CT extracted from the fins, mantle and arms of jumbo squid during ice storage (20 days) was evaluated. The CT was fractionated based on solubility [NaCl-soluble (SSCT) and insoluble (ICT)]. The solubility of the CT was affected during ice storage. An increase in the thermal resistance of the SSCT after 10 days with a subsequent decrease was found in the mantle. Furthermore, the ICT was thermally more resistant than the SSCT in all the anatomical regions. Finally, the electrophoretic profile revealed that structural changes occurred, causing changes in its solubility, due to an increase in the thermal resistance. Practical Applications Jumbo squid ( Dosidicus gigas) is an important seafood resource in Mexico, which is commercialized primarily iced and fresh-frozen. Its muscle connective tissue (CT) has different physicochemical characteristics that differ from other seafood products; it is thermally more resistant and might be responsible for the textural changes during ice storage. Moreover, specific studies about the behavior of CT proteins in such organism may result in improved post-catch management of jumbo squid muscle, focused on the processing of the species in the food industry or anywhere that CT proteins are used as raw material. The main objective of this research is to investigate solubility changes and thermal resistance of CT proteins of iced jumbo squid mantle. [ABSTRACT FROM AUTHOR]