Review of the Greening Reaction by Thermal Treatment: New Insights Exploring the Structural Implications of Myoglobin.

Myoglobin is the main factor responsible for muscle pigmentation in tuna; muscle color depends upon changes in the oxidative state of myoglobin. The tuna industry has reported muscle greening after thermal treatment involving metmyoglobin (MetMb), trimethylamine oxide (TMAO), and free cysteine (Cys). It has been proposed that this pigmentation change is due to a disulfide bond between a unique cysteine residue (Cys10) found in tuna MetMb and free Cys.

Sulfmyoglobin production by free cysteine during thermal treatment: Involvement of heme iron in the production of free radicals.

The meat greening is an abnormal pigmentation related to microbiological contamination and lipid oxidation during storage. This color change results from sulfmyoglobin (SulfMb) production promoted by the reaction between metmyoglobin (MetMb), HO and thiol compounds. Spectral studies on cooked meat suggested the production of SulfMb, probably due to the increment of free radicals during thermal treatment.

Influence of pH, ionic strength and isoascorbic acid on the gel-forming ability of Jumbo squid muscle (Dosidicus gigas).

The effect of pH and ionic strength (μ) on the extraction capacity of myofibrillar proteins from Jumbo squid mantle muscle along with the addition of isoascorbic acid (IA) in its gel-forming ability (GFA) were evaluated. The results indicate that μ had a greater impact (p < 0.05) than pH on the extraction of muscle myofibrillar proteins.

Partial Characterization of a Low-Molecular-Mass Fraction with Cryoprotectant Activity from Jumbo Squid () Mantle Muscle.

Freezing conditions affect fish muscle protein functionality due to its denaturation/aggregation. However, jumbo squid () muscle protein functionality remains stable even after freezing, probably due to the presence of low-molecular-mass compounds (LMMC) as cryoprotectants. Thus, water-soluble LMMC (<1 kDa) fraction obtained from jumbo squid muscle was evaluated by Fourier transform infrared spectrometry.

Effect of acid treatment on extraction yield and gel strength of gelatin from whiptail stingray () skin.

Chemical properties of fish gelatins differ from those of conventional mammalian sources, representing an attractive technological alternative for the food industry. Ray filleting generates a considerable amount of skin waste that can be used as a collagen source for gelatin extraction. Thus, this research evaluated the HCl and CHCOOH effect, at 0.

Acidic proteases from Monterey sardine (Sardinops sagax caerulea) immobilized on shrimp waste chitin and chitosan supports: searching for a by-product catalytic system.

Solid wastes generated from the seafood industry represent an important environmental pollutant; therefore, utilization of those wastes for the development of processing biochemical tools could be an attractive and clean solution for the seafood industry. This study reports the immobilization of semi-purified acidic proteases from Monterey sardine stomachs onto chitin and chitosan materials extracted from shrimp head waste. Several supports (chitosan beads, chitosan flakes, and partially deacetylated flakes) were activated either with genipin or Na-tripolyphosphate and evaluated as a mean to immobilize acidic proteases.

Trypsin from viscera of vermiculated sailfin catfish, Pterygoplichthys disjunctivus, Weber, 1991: its purification and characterization.

Pterygoplichthys disjunctivus viscera trypsin was purified by fractionation with ammonium sulphate, gel filtration, affinity and ion exchange chromatography (DEAE-Sepharose). Trypsin molecular weight was approximately 27.5kDa according to SDS-PAGE, shown a single band in zymography.

Purification and characterization of chymotrypsin from viscera of vermiculated sailfin catfish, Pterygoplichthys disjunctivus, Weber, 1991.

Pterygoplichthys disjunctivus viscera chymotrypsin was purified by fractionation with ammonium sulfate (30-70 % saturation), gel filtration, affinity, and ion exchange chromatography. Chymotrypsin molecular weight was approximately 29 kDa according to sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE), shown a single band in zymogram. Electrofocusing study suggested being an anionic enzyme (pI ≈ 3.

Functional properties of fish protein hydrolysates from Pacific whiting(Merluccius productus) muscle produced by a commercial protease.

Pacific whiting (Merluccius productus) muscle was used to produce hydrolysates with 10%, 15% and 20% degree of hydrolysis (DH) using the commercial protease Alcalase(®) and were characterized at pH 4.0, 7.0 and 10 according their solubility, emulsifying and foaming properties.