Effects of sous vide cooking combined with ultrasound pretreatment on physicochemical properties and microbial communities of Russian sturgeon meat (Acipenser gueldenstaedti).

BACKGROUND: The production of Russian sturgeon is expanding rapidly in China but it is necessary to adopt measures to extend the shelf life of sturgeon meat. Previous studies found that sous vide cooking (SVC) at 60 °C increased the protein and lipid oxidation. The addition of antioxidant substances reduced the acceptance of the product. The effect of combination SVC and ultrasound pretreatment was therefore investigated. RESULTS: Results showed that SVC at 50 °C combined with ultrasound effectively restrained the growth of total viable counts (TVC) in samples. Meanwhile, the main dominant genera changed from Pseudomonas to Carnobacterium and the number of microbial species decreased. The odor profile of Russian sturgeon meat was more stable and the lipoxygenase (LOX) activity decreased more rapidly after treating with SVC and ultrasound. Importantly, more stable protein aggregates were formed in samples treated by SVC 50 °C together with ultrasound pretreatment, so the protein and lipid oxidation were slowed during storage. Higher springiness values were obtained and the color of sturgeon meat was lighter under these conditions. CONCLUSION: The combination of SVC 50 °C and ultrasound pretreatment effectively inhibited the microbial growth of Russian sturgeon meat at lower oxidation levels. These findings theoretically support the preservation and development of sturgeon meat, and the application of SVC technology. © 2022 Society of Chemical Industry.

4-{(Z)-(sec-Butyl-amino)(phen-yl)methyl-ene}-3-methyl-1-phenyl-1H-pyrazol-5(4H)-one.

In the title compound, C(21)H(23)N(3)O, the dihedral angles formed by the pyrazolone ring with two phenyl rings are 10.38 (8) and 76.94 (6)°. The sec-butyl-amino group is disordered over two positions, with refined site-occupancy factors of 0.730 (4) and 0.270 (4). The compound could potentially be ligand stabilized in the solid state in a keto-enamine tautomeric form. The amine functionality is involved in an intra-molecular N-H⋯O hydrogen bond, while weak inter-molecular C-H⋯O and C-H⋯N hydrogen bonds participate in the formation of the crystal structure.

(4Z)-4-[(4-Methoxy-benzyl-amino)(phen-yl)methyl-ene]-3-methyl-1-phenyl-1H-pyrazol-5(4H)-one.

In the title compound, C(25)H(23)N(3)O(2), the dihedral angles formed by the pyrazolone ring with the three aromatic rings are 14.59 (7), 79.35 (5) and 87.10 (6)°. Three intra-molecular C-H⋯O, C-H⋯N and N-H⋯O hydrogen-bond inter-actions are present. The crystal structure is stabilized by two weak inter-molecular C-H⋯O and C-H⋯N hydrogen-bond inter-actions.