Effect of Conductivity, pH, and Elution Buffer Salinity on Glycomacropeptide Recovery from Whey Using Anion Exchange Chromatography

ABSTRACT: The objective of this study was to investigate the effect of whey conductivity, pH, and the salt concentration of the elution buffer on glycomacropeptide recovery and its extent of contamination using anion exchange chromatography. Glycomacropeptide was isolated from Mozzarella whey. Samples were analyzed for glycomacropeptide and contaminating whey proteins. Mass balances and percent recoveries were calculated from these data. Glycomacropeptide recovery increased substantially with decreasing conductivity and increasing pH of the whey feed stream. Increasing the pH, but not increasing the conductivity, increased contamination of the glycomacropeptide by primarily beta-lactoglobulin. Salt concentration of at least 0.1 M was required for complete elution of bound glycomacropeptide. These data define conditions needed for glycomacropeptide recovery by a process chromatography system that uses food-grade buffers, operates at industrially relevant flow rates, and achieves up to 98% recovery.     

Purification,characterization, and inhibition sensitivity of peroxidase from wheat (Triticum aestivum ssp. vulgare)

The purification and characterization of peroxidase is currently growing interests since peroxidases have implications in various industrial and biochemical applications. In this study, wheat peroxidase was purified using (NH₄)₂SO₄ precipitation, CM-Sephadex cation exchange, and gel filtration chromatographies. Enzyme purity and molecular mass were checked by sodium dodecyl sulphate polyacrylamide gel electrophoresis. Enzyme kinetics was studied using two substrates: guaiacol and hydrogen peroxide (H₂O₂). K_m and V_max values were calculated from Lineweaver-Burk graph for each substrate. Wheat peroxidase activity has been enhanced 284-fold. Wheat peroxidase had molecular mass of 38.8 kDa. K_m values for guaiacol and H₂O₂ were found as 2.467 mM and 7.307 mM, respectively. The pH and temperature optima were 5.5 and 40.0°C, respectively. Also, the enzyme was highly inhibited by citric acid and Cetyltrimethylammonium bromide.     

Changes of Phenolic Acids During Aging of Organic Wines

Grapes (Vitis vinifera L. origin var: Carignane, Cabernet Sauvignon, Merlot, Grenache, Columbard, and Semillon) were cultivated and processed according to accepted organic agriculture and organic wine techniques. Aged wines (5 years) were evaluated for changes of their phenolic acids. The highest reduction of gallic acid concentrations were determined in Cabernet Sauvignon (24.36 mg/L) and Carignane (16.00 mg/L) wines. The quantities of p-hydroxybenzoic acid decreased mostly in Carignane (22.47 mg/L) and Columbard (20.84 mg/L) wines. The decreases of syringic acid were dominant in Cabernet Sauvignon (2.34 mg/L) and Carignane (1.69 mg/L) wines. In the case of ferulic acid, the highest reduction was determined in Cabernet Sauvignon (3.97 mg/L) wines. The decreases of p-coumaric acid contents were the same and mostly in Merlot (1.06 mg/L) and Grenache (1.035 mg/L) wines. The principal component analyses results demonstrated the relations among aged wines produced from different grape varieties and their phenolic acids. The distribution of data was accumulated into two groups. The first group included total phenols, gallic acid, p-hydroxybenzoic acid, syringic acid, p-coumaric acid, and Merlot/Carignane/Grenache wines. The second one included ferulic acid and Cabernet Sauvignon wine.