Kamile Nazan Turhan

Water activity (a_w) and moisture content (MC) of Turkish liquid flower and pine honeys were determined. Samples (706 flower and 257 pine) were collected during the honey harvesting seasons of 2010-2014 from 137 apiaries in locations with different climatic conditions all over the land. Up to date, this work is the first one seeking for a correlation between a_w and MC for Turkish honeys, and also it is the largest and longest one among similar works to the best of the researchers’ knowledge. The ranges of a_w and MC values of the Turkish honeys were in agreement with the literature. a_w was determined between 0.470 and 0.563 for the flower honeys, and between 0.492 and 0.589 for the pine honeys. MC was measured between 15.0 and 20.4% (m/m) for the flower honeys and between 15.1 and 20.4% (m/m) for the pine honeys. Statistically different linear regression equations (a_w versus MC) fitted data of the flower and pine honeys with significantly high coefficients of determinations (R²> 0.848), small mean absolute errors (< 1.39%) and no biases. The linear equations were analogous to equations giving the correlation between a_w and MC for other honeys in the literature.

Olive leaf extract (OLE) (Olea europaea L.) is a natural product that has antimicrobial effect on many food pathogens. In this study, methylcellulose (MC) based antimicrobial films containing 0.5–3% (w/v) OLE and glycerol (1.6%, v/v) were produced. The effects of OLE amount on the water vapour permeability (WVP), mechanical and antimicrobial properties of the films were investigated. The films were effective against Staphylococcus aureus (ATCC 25923). The OLE in the film solution caused a decrease in WVP and elongation (E), and an increase in tensile strength (TS). The MC films containing 1.5% (w/v) OLE were applied on Kasar cheese slices inoculated with S. aureus. The count of S. aureus decreased 0.68 and 1.22 log cycle at the 7th and 14th days, respectively. Copyright © 2009 John Wiley & Sons, Ltd.

Water vapour permeability (WVP) and mechanical properties were assessed in edible films prepared from methylcellulose (MC) and MC–whey protein isolate (WPI) or MC–whey protein concentrate (WPC). Glycerol (Gly) was used as the plasticizer. Two MC–WP films were formulated. For Group I films, the mass ratio of WP : Gly was constant, whereas for Group II films the mass ratio of polymer (MC + WP) : Gly was constant. The WVP of MC–Gly film decreased with increasing MC concentration, while the tensile strength (TS) and percent elongation (E) increased. The WVP of Group I and Group II films decreased erratically and TS increased when the MC concentration was increased. Group I films had higher TS values than Group II films at the same MC : WP ratios. E of both groups increased with increasing MC concentration (p < 0.05), excluding the films with the highest MC : WP ratio tested (0.8) in Group I films. Group I films had lower E values than Group II films at the same MC : WP ratios. MC effectively governed WVP, TS and E of the WP films. Generally, MC–WP films of this work showed lower WVP than that of MC‐ and WP‐based edible films in the literature. This can potentially make MC–WP films a suitable film material for moisture‐sensitive food products. Copyright © 2005 John Wiley & Sons, Ltd.

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.

The objective of this work was to develop a process to fractionate proteins from lactic acid whey, which is underused compared with sweet whey, using food‐grade buffers and cation‐exchange chromatography. Bound proteins were desorbed either all at once to make whey protein isolate (WPI), or in 2 steps to 1st make α‐lactalbumin (ALA) and then WPI depleted in ALA. Recovery and purity using lactic acid whey were comparable to previously reported processes using sweet whey. Capacity and throughput were slightly lower using lactic acid whey. This research provides a basis for adding value to the 6 million metric tons of lactic acid whey produced annually in the United States.