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Shock waves, as used in medicine, can induce cell permeabilization, genetically transforming filamentous fungi; however, little is known on the interaction of shock waves with the cell wall. Because of this, the selection of parameters has been empirical. We studied the influence of shock waves on the germination of Aspergillus niger, to understand their effect on the modulation of four genes related to the growth of conidia. Parameters were varied in the range reported in protocols for genetic transformation. Vials containing conidia in suspension were exposed to either 50, 100 or 200 single-pulse or tandem shock waves, with different peak pressures (approximately 42, 66 and 83 MPa). In the tandem mode, three delays were tested. To equalize the total energy, the number of tandem "events" was halved compared to the number of single-pulse shock waves. Our results demonstrate that shock waves do not generate severe cellular effects on the viability and germination of A. niger conidia. Nevertheless, increase in the aggressiveness of the treatment induced a modification in four tested genes. Scanning electron microscopy revealed significant changes to the cell wall of the conidia. Under optimized conditions, shock waves could be used for several biotechnological applications, surpassing conventional techniques. [ABSTRACT FROM AUTHOR]

Commercially, crab meat is obtained by hand-picking after a cooking process, followed by pasteurizing or canning. Jumbo lump is one of the pieces of meat obtained from the blue crab. The aim of this study was to evaluate the effect of the commercial cooking process (boiling and steaming) on the mechanical and functional properties of whole jumbo lump and the gels obtained from cooked and minced jumbo lump from blue crab (Callinectes sapidus). The gels were prepared combining the washing process and microbial transglutaminase. The boiling and steaming processes showed a different effect on the textural and color properties. Whole jumbo lump pieces cooked by immersion in boiling water showed a higher hardness value as compared to steamed jumbo lump pieces, suggesting a different internal structural. The cooking processes used in this study did not modify the water holding capacity, gelling capability, or color of the minced jumbo lump. The addition of microbial transglutaminase to washed minced jumbo lump improved the hardness, cohesiveness, and chewiness of gels elaborated with boiled or steamed jumbo lump, which allowed the textural properties similar to those of the whole jumbo lump. [ABSTRACT FROM AUTHOR]

The effect of washing cycles and microbial transglutaminase on the gelation properties of crabmeat was evaluated. The blue crab (Callinectes sapidus) was cooked at 120°C for 30 min before obtaining the meat. Cooked meat was homogenized in a cutter with 0 (control) or 0.5 microbial transglutaminase (MTGase), stuffed in steel tubes and setted at 40 °C for 30 min before cooking at 90 °C for 15 min. Control samples were cooked directly at 90 °C. Changes in color, mechanical properties (puncture test) and water holding capacity (WHC) were evaluated. Adding MTGase improved the mechanical properties of crabmeat gels after one or three washing cycles in both cooking processes (setting and cooked directly). The results suggest that a single washing process produces crab meat gels with good mechanical properties while maintaining soluble proteins, responsible for the distinctive flavor of crabmeat. [ABSTRACT FROM AUTHOR]

There is an increasing interest in the development of meat processed products enriched with antioxidant dietary fiber to augment the consumption of these health beneficial compounds. This study aimed to evaluate the nutritional, nutraceutical, and antioxidant potential, as well as the physicochemical properties of minced tilapia fillets (meat) gels with added amaranth seed or sprout flours (0%, 2%, 4%, 8%, and 10% w/w). Dietary fiber content was significantly increased with the addition of amaranth seed (1.25–1.75-fold) and sprout flours (1.99–3.21-fold). Tilapia gels with added 10% amaranth seed flour showed a high content of extractable dihydroxybenzoic acid and cinnamic acid, whereas the addition of 10% amaranth sprout flour provided a high and wide variety of bioactive compounds, mainly amaranthine and bound ferulic acid. The addition of amaranth seed and sprout flours increased hardness (1.01–1.73-fold) without affecting springiness, decreased luminosity (1.05–1.15-fold), and increased redness and yellowness. Therefore, amaranth seed and sprout flours could be used as functional ingredients for the development of fish products rich in bioactive compounds. [ABSTRACT FROM AUTHOR]

This study was carried out to evaluate the effect of high pressure processing (HPP) and thermal treatments on the gelling properties of proteins from blue crab meat. Crabmeat was pressurized at 100, 300, and 500 MPa (10 °C/5 min) with and without heating (90 °C/20 min) after the HPP treatment. Treated samples were analyzed by protein interactions, differential scanning calorimetry (DSC), Fourier transform infrared spectroscopy (FTIR), and dynamic rheometry. Protein gelation after pressurization was based on physical interactions which were modified after HPP treatment; meanwhile, thermal gelation was based mainly on the formation of covalent bonds. DSC showed that pressure levels over 300 MPa reduced myosin denaturation temperature indicating protein unfolding. HPP treatment at 100 MPa led to a partial protein denaturation effect. FTIR results showed a reduction in the fraction of α-helix structure along with a development of β-sheet portion as a result of protein denaturation promoted by the application of pressure. The sweep temperature analysis indicated that the combination of treatments stabilized the protein network in the gels from blue crab meat. The combination of pressure (100 MPa) and heat (90 °C) treatments allowed obtaining gels from crabmeat proteins with optimal rheological properties. • High-pressure processing can modify functional properties of blue crab proteins. • Pressure levels of 100 MPa promotes a partial protein denaturation. • HPP-treated Crabmeat gels are flexible networks stabilized by noncovalent cross-links. • HPP with heat treatment allows crabmeat gels with stable non-rigid protein structure. [ABSTRACT FROM AUTHOR]