Membrane based detection of genetically modified organisms in some representatives food

Recently, DNA-based techniques became very common for the detection of genetically modified organisms (GMOs) in food products. For rapid and easy detection of GMOs, polymerase chain reaction (PCR) screening methods, which amplify common transgenic elements, are applied in routine analysis. Incorporation of PCR and membrane method introduced in this study offer an alternative detection of GMOs. In this study, a total of 32 samples and three certified reference materials were tested for the existence of the 35S promoter of cauliflower mosaic virus (CaMV) and 5-enol-pyruvyl-shikimate-3-phosphate synthase (EPSPS) gene residues. Dot blot screening system introduced in this study can be routinely used as a semi-quantitative screening of GMOs.     

Milk fat globule size,phospholipid contents and composition of milk from purebred and Alpine-crossbred Mid-Eastern goats under confinement or grazing condition

Milk fat globule (MFG) size and phospholipids (PL) content and composition were determined in milk collected at 65 (pretreatment), 110, 135 and 170 days of lactation from goats randomly assigned to grazing in Mediterranean brushland or fed clover hay indoors, in addition to concentrate. Daily feed intake and dietary contents of neutral detergent fibre and acid detergent fibre were higher in grazing goats, associated with milk richer in fat, with larger MFGs and 20% higher PL content. Smaller MFGs, produced by all confinement groups, was associated with 15 μg g⁻¹ fat higher milk PL content. The greatest effect was found in the Damascus goats, with over 44% higher PL concentration, on milk fat basis, in the confined compared with grazing group. Our understanding of how PL content is modulated by the interaction between genetic background and nutrition will enable to achieve either PL-rich milk or PL-enriched milk fat.     

Comparative study of proximate composition and amino acid in farmed and wild Pseudobagrus ussuriensis muscles

The proximate composition and amino acid compositions of the muscle of wild and farmed Pseudobagrus ussuriensis were compared. The lipid content of the farmed fish was significantly higher, while moisture content was significantly lower, than those of the wild fish. Pseudobagrus ussuriensis protein has a well‐balanced amino acid composition. The percentages of total amino acids, essential amino acids, nonessential amino acids and delicious amino acids were significantly higher in the wild than those in farmed fish. The ratios of W_EAA to W_TAA (42.78%–43.02%) and W_EAA to W_NEAA (85.52%–87.74%) were comparable to the reference values of 40% and above 60% recommended by FAO/WHO. According to the amino acid scores, methionine would have been described as the first limiting amino acid, and Lys had the highest score for the protein in both wild and farmed Pseudobagrus ussuriensis. This study shows that Pseudobagrus ussuriensis under investigation have high nutritional qualities and are good protein resources.     

β-Lactoglobulin nanofibrils: The long and the short of it

The bovine whey protein β-lactoglobulin will self-assemble into amyloid-like nanofibrils when heated at pH ≤ 3 and temperatures ≥75 °C. These fibrils have diameters <10 nm and lengths that can exceed 10 μm. The length and stiffness of fibrils depends on ionic strength; heating at low ionic strength produces long semi-flexible fibrils, whereas heating with added salts produces highly flexible ‘worm-like’ fibrils that are an order of magnitude shorter. Over the last two decades there has been a substantial research effort focused on imaging fibrils, manipulating conditions to accelerate fibril formation, and characterising microstructural and rheological properties of fibril dispersions. Here we review the major mechanistic findings, explore potential applications for fibrils as food ingredients, and highlight the major gaps in knowledge surrounding these intriguing self-assembled structures.     

Esterase activity inspired selection and characterization of zearalenone degrading bacteria Bacillus pumilus ES-21

Zearalenone (ZEN), mainly produced by Fusarium species, is an estrogenic mycotoxin which causes reproductive disorders in livestock. In this study, we described a simple and rapid method for screening of ZEN-degrading bacteria by esterase activity assay. Soil bacteria strains were first tested for their esterase activities, then active strains were further evaluated for their ZEN-degrading potentials. A bacterial strain named Bacillus pumilus ES-21 was detected to be able to eliminate ZEN in the culture medium. ZEN degradation conditions were optimized through response surface methodology and the result showed that the degradation rate of ZEN by Bacillus pumilus ES-21 was up to 95.7% at the ZEN concentration of 17.9 μg/ml within 24 h. One of the degradation product was proposed to be 1-(3,5-dihydroxyphenyl)-6′-hydroxy-l′-undecen-l0′-one according to LC-TOF-MS/MS analysis. This study provided a strategy for the isolation of ZEN degrading microbes and a promising degrading strain.     

Thermal markers arising from changes in the protein component of milk

Classification of heat load applied to milk requires the detection of parameters appropriately related to the intensity of the heat treatment. Current analytical methods based on heat-induced changes in the protein component of milk have been directed either to determine the amount of protein-derived products arised from heat treatments or to evaluate the extent of thermal denaturation of milk proteins. Lately, a new analytical strategy has been developed according to the occurrence of three major whey proteins, namely bovine serum albumin (BSA), beta-lactoglobulin (βlg) and alfa-lactalbumin (αla), normally soluble at pH 4.6 in raw milk, in the pH 4.6 insoluble protein fraction recovered from heat-treated milk. The results have shown that pH 4.6 insoluble BSA, βlg and αla, as detected by ELISA in milk, can be regarded as thermal markers suited for either dairy process control or regulation purposes.     

Physicochemical and adhesive properties,microstructure and storage stability of whey protein-based paper glue

The objective of this study was to formulate and evaluate a novel liquid paper glue based on a renewable material, polymerized whey proteins (PWP), and a synthetic polymer, polyvinylpyrrolidone (PVP) K90. Both PWP and PVP separately and/or cumulatively played important roles in the viscosity and bonding strength of the glue. Two optimized formulations (prototype A and prototype B) were analyzed for physicochemical and adhesive properties, microstructure and storage stability. A commercial product was used as a reference for comparison. Both prototypes had comparable bonding strength with the control, showed full substrate failure in the lap-shear strength tests, and exhibited faster setting property than the control. Viscosity of the prototypes was lower than that of the control, but they were still easy for application and spread. Scanning electron microscope (SEM) analysis showed that combined PVP and PWP formed more compact networks compared with those formed by PWP alone. Not only did they have desirable adhesive properties, both prototypes with addition of an antimicrobial agent also had stable shelf lives. Neither significant changes of bonding strength, viscosity or appearance, nor growth of microbes was observed during storage at 23 °C or 40 °C for 12 months. In conclusion, the whey protein based paper glue has comparable functional properties to the commercial product.     

Inhibitory effects of garlic and other spices on biogenic amine production in Myeolchi-jeot,Korean salted and fermented anchovy product

This study was carried out to reduce biogenic amine contents in Myeolchi-jeot, Korean salted and fermented anchovy (Engraulis japonicus). The effects of a variety of spices including ginger, garlic, green onion, red pepper, clove and cinnamon, on biogenic amine production were determined by HPLC. The greatest inhibitory effect on biogenic amine production was observed in the culture treated by garlic extract. In the culture, the contents of putrescine, cadaverine, histamine, tyramine and spermidine were reduced by up to 11.2%, 18.4%, 11.7%, 30.9% and 17.4%, respectively, compared to control. The other spice extracts tested showed less or no effect in reducing biogenic amine contents. In addition, the extract of garlic showed the highest antimicrobial activity against the amine producers tested. The extract of garlic at a concentration of 5% (weight basis) was finally applied to the ripening of Myeolchi-jeot in situ, and then overall production of biogenic amines in Myeolchi-jeot was found to be reduced by up to 8.7%, compared to control. Consequently, it is expected that the findings of this study might be helpful for enhancing the safety of Myeolchi-jeot.