RESUMEN

BACKGROUND: Soy protein isolate (SPI) is widely used in the food industry because of its nutritional and functional properties. During food processing and storage, the interaction with co-existing sugars can cause changes in the structural and functional properties of SPI. In this study, SPI-l-arabinose conjugate (SPI:Ara) and SPI-d-galactose conjugate (SPI:Gal) were prepared using Maillard reaction (MR), and the effects of five-carbon/six-carbon sugars on the structural information and function of SPI were compared. RESULTS: MR unfolded and stretched the SPI, changing its ordered conformation into disorder. Lysine and arginine of SPI were bonded with the carbonyl group of sugar. The MR between SPI and l-arabinose has a higher degree of glycosylation compared to d-galactose. MR of SPI enhanced its solubility, emulsifying property and foaming property. Compared with SPI:Ara, SPI:Gal exhibited better aforementioned properties. The functionalities of amphiphilic SPI were enhanced by MR, SPI:Gal possessed better hypoglycemic effect, fat binding capacity and bile acid binding ability than SPI:Ara. MR endowed SPI with enhanced biological activities, SPI:Ara showed higher antioxidant activities, and SPI:Gal exhibited stronger antibacterial activities. CONCLUSION: Our work revealed that l-arabinose/d-galactose exhibited different effects on the structural information of SPI, and further affected its physicochemical and functional property. © 2023 Society of Chemical Industry.

Asunto(s)

Galactosa , Proteínas de Soja , Proteínas de Soja/química , Arabinosa , Reacción de Maillard , Carbono , Productos Finales de Glicación Avanzada

RESUMEN

Three kinds of phenolic acid-grafted soluble soybean polysaccharide (SSPS) with similar grafting ratios were prepared, and their structure was characterized by FT-IR, UV-vis and 1 H NMR. The impact of phenolic acid on the antioxidant activity of SSPS was evaluated. Then, films were prepared by using phenolic acid-grafted SSPS. The physical, mechanical and biological performances of phenolic acid-grafted SSPS films were further investigated. The results indicated that an ester linkage was formed between the SSPS and phenolic acid. The grafting ratio of para-hydroxybenzoic acid, protocatechuic acid and gallic acid-grafted SSPS was 29.45, 31.76 and 30.74 mg/g, respectively. Phenolic acid endowed SSPS with improved antioxidant properties. Gallic acid (GA)-grafted SSPS possessed the best DPPH radical scavenging ability and reducing power, which may be related to the three phenolic hydroxyl groups in GA. Phenolic acid-grafted SSPS films showed increased moisture content and decreased water solubility compared to SSPS film. The phenolic acid-g-SSPS decreased the mechanical properties but enhanced the water vapor barrier property, and antioxidant and antibacterial properties of SSPS film. Meanwhile, the para-hydroxybenzoic acid-grafted SSPS film showed the lowest water vapor permeability (3.70 × 10-7 g mm/h cm2 Pa), and the GA-grafted SSPS film exhibited the best antioxidant and antibacterial activities.

RESUMEN

The chlorogenic acid-grafted-chitosan conjugates (CA-g-CS) with three grafting ratios were synthesized. Then the CA-g-CS conjugated films (CA-g-CS I, CA-g-CS II, and CA-g-CS III) and the CA-CS incorporated films (CA-CS I, CA-CS II, and CA-CS III) with equivalent chlorogenic acid content were prepared, respectively. The physical, mechanical, and biological properties of CA-g-CS conjugated and CA-CS incorporated films were evaluated. Further, the CA-g-CS III and CA-CS III were chosen to evaluate their preservative effect on shrimp. Compared with CS film, CA-g-CS conjugated and CA-CS incorporated films showed enhanced opacity and water solubility, changed thickness and water vapor permeability, and reduced moisture content, tensile strength and elongation at break. Conjugation or incorporation of CA enhanced antioxidant and antibacterial activities of CS films, and these activities increased with the increasing of CA content. CA-g-CS III showed better preservative effect on shrimp than CA-CS III in terms of weight loss, pH value, total volatile basic nitrogen, total bacterial count and sensory score of shrimp during storage. Therefore, CA-g-CS conjugated films exhibited better bioactivities and preservative effect on shrimp than CA-CS incorporated films. Compared with incorporation, conjugation of CA with CS is a more efficient way to improve properties of CS film.

Asunto(s)

Quitosano/química , Ácido Clorogénico/química , Conservantes de Alimentos/química , Conservantes de Alimentos/farmacología , Membranas Artificiales , Penaeidae/efectos de los fármacos , Animales , Antibacterianos/química , Antibacterianos/farmacología , Antioxidantes/química , Antioxidantes/farmacología , Fenómenos Químicos , Embalaje de Alimentos , Conservación de Alimentos , Fenómenos Mecánicos , Permeabilidad , Fenoles/química , Espectroscopía Infrarroja por Transformada de Fourier , Vapor

RESUMEN

Vibrio cholerae is a leading waterborne pathogenic bacterium worldwide. It can cause human cholera that is still pandemic in developing nations. Detection of V. cholerae contamination in drinking water and aquatic products is imperative for assuring food safety. In this study, a simple, sensitive, specific, and visualized method was developed based on loop-mediated isothermal amplification (LAMP) (designated sssvLAMP) to detect virulence-associated (ctxA, tcpA, hapA, mshA, pilA, and tlh) and species-specific (lolB) genes of V. cholerae. Three pairs of oligonucleotide primers (inner, outer, and loop primers) were designed and or synthesized to target each of these genes. The optimal conditions of the sssvLAMP method was determined, and one-step sssvLAMP reaction was performed at 65°C for 40 min. Positive results were simply read by the naked eye via color change (from orange to light green) under the visible light, or by the production of green fluorescence under the UV light (260 nm). The sssvLAMP method was more efficient in detecting 6.50 × 101-6.45 × 104-fold low number of V. cholerae cells, and more sensitive in V. cholerae genomic DNA (1.36 × 10-2-4.42 × 10-6 ng/reaction) than polymerase chain reaction (PCR) method. Among 52 strains of V. cholerae and 50 strains of non-target species (e.g., other Vibrios and common pathogens) examined, the sensitivity and specificity of the sssvLAMP method were 100% for all the target genes. Similar high efficiency of the method was observed when tested with spiked samples of water and aquatic products, as well as human stool specimens. Water from various sources and commonly consumed fish samples were promptly screened by this simple and efficient visualized method and diversified variation in the occurrence of the target genes was observed. V. cholerae strains could be mostly detected by the presence of hapA and tlh alone or in combination with other genes, indicating a variable risk of potentially pathogenic non-O1/O139 strains in edible food products. This novel LAMP method can be a promising tool to address the increasing need of food safety control of aquatic products.

RESUMEN

Two new one-dimensional coordination polymers, viz. the title compounds, [Co[C(CN)(3)](2)(C(6)H(5)N(3))(2)](n), (I), and [Mn[C(CN)(3)](2)(C(5)H(8)N(2))(2)](n), (II), have been synthesized and characterized by X-ray diffraction. Both complexes consist of linear chains with double 1,5-tricyanomethanide bridges between neighbouring divalent metal ions. The Co and Mn atoms are located on centres of inversion. In (I), the coordination environment of the Co(II) atom is that of an elongated octahedron. The Co(II) atom is coordinated in the equatorial plane by four nitrile N atoms of four bridging tricyanomethanide ions, with Co-N distances of 2.106 (2) and 2.110 (2) A, and in the apical positions by two N atoms from the benzotriazole ligands, with a Co-N distance of 2.149 (2) A. The [Co[C(CN)(3)](2)(C(6)H(5)N(3))(2)] units form infinite chains extending along the a axis. These chains are crosslinked via a hydrogen bond between the uncoordinated nitrile N atom of a tricyanomethanide anion and the H atom on the uncoordinated N atom of a benzotriazole ligand from an adjacent chain, thus forming a three-dimensional network structure. In (II), the Mn(II) atom also adopts a slightly distorted octahedral geometry, with four nitrile N atoms of tricyanomethanide ligands [Mn-N = 2.226 (2) and 2.227 (2) A] in equatorial positions and two N atoms of the monodentate 3,5-dimethylpyrazole ligands [Mn-N = 2.231 (2) A] in the axial sites. In (II), one-dimensional polymeric chains extending along the b axis are formed, with tricyanomethanide anions acting as bidentate bridging ligands. A hydrogen bond between the uncoordinated nitrile N atom of the tricyanomethanide ligand and the H atom on the uncoordinated N atom of a 3,5-dimethylpyrazole group from a neighbouring chain links the molecule into a two-dimensional layered structure.