Deokjo Jo

Quality Comparison of Commercial Cider Vinegars by Their Acidity Levels

The quality of commercial cider vinegars was compared according to their acidity levels (low, general, double strength and triple strength). The pH, reducing sugar content and brown color intensity decreased, while the total acidity increased with the increasing acidity levels, which may be resulted from difference in formulation and manufacturing procedures. The free sugars were mainly composed of fructose and glucose, which were the highest in low acidity vinegar, followed by double strength, general, and triple strength acidity vinegars. Acetic acids and malic acids were identified as the major organic acids. The citric acid concentration was the highest in triple strength vinegars. The contents of total phenolics and flavonoids were the highest in low acidity vinegars, which indicated their dependence on the apple juice content. DPPH and ABTS radical scavenging abilities were the highest in low acidity vinegars, that showed high amounts of antioxidants.

Investigation of Different Factors Affecting the Electron Spin Resomance-based Characterization of Gamma-irradiated Fresh, White, and Red Ginseng.

Fresh (raw roots), white (dried), and red (steamed-drid) ginseng samples were gamma-irradiated at 0 to 7 kGy. Electron spin resonance (ESR) technique was used to characterize the irradiation status of the samples, targeting the radiation-induced cellulose radicals after different sample pretreatments. All non-irradiated samples exhibited a single central signal (g=2.006), whose intensity showed significant increase upon irradiation. The ESR spectra from the radiation-induced cellulose radicals, with two side peaks (g=2.0201 and g=1.9851) equally spaced (±3 mT) from the central signal, were also observed in the irradiated samples. The core sample analyzed after alcoholic-extraction produced the best results for irradiated fresh ginseng samples. In the case of irradiated white and red ginseng samples, the central (natural) and radiation-induced (two-side peaks corresponding to cellulose radical) signal intensities showed little improvement on alcoholic-extraction. The water-washing step minimized the effect of Mn2+, but reduced the intensity of side peaks making them difficult to indentify. The effect of different origins was negligible, however harvesting year showed a clear effect on radiation-induced ESR signals.

Quality Properties of Pear Vinegars with High-Acidity under Different Fermentation Conditions

High-acidity vinegar was manufactured using pear concentrate by fed-batch fermentation without additional nutrients, and the physicochemical properties and volatile components were investigated at different fermentation stages (Stages 1-4) and at various initial alcohol concentrations (IAC; 6-9%). The levels of reducing sugar, free amino acids, total phenolic content, total flavonoid content, and radical scavenging ability increased slightly during Stage 4 (high-acidity vinegar), which was affected by alcohol feeding. The contents of approximately 20 types of volatile compounds differed between the moderate- and high-acidity vinegar samples, as determined by solid-phase microextraction/gas chromatographymass spectroscopy. The level of acetic acid in high-acidity vinegar increased according to the initial alcoholic content applied. The high-acidity vinegar produced by fed-batch culture at an IAC of 6-7% showed improved physicochemical and volatile properties as compared to the moderate-acidity vinegar.High-acidity vinegar was manufactured using pear concentrate by fed-batch fermentation without additional nutrients, and the physicochemical properties and volatile components were investigated at different fermentation stages (Stages 1-4) and at various initial alcohol concentrations (IAC; 6-9%). The levels of reducing sugar, free amino acids, total phenolic content, total flavonoid content, and radical scavenging ability increased slightly during Stage 4 (high-acidity vinegar), which was affected by alcohol feeding. The contents of approximately 20 types of volatile compounds differed between the moderateand high-acidity vinegar samples, as determined by solid-phase microextraction/gas chromatographymass spectroscopy. The level of acetic acid in high-acidity vinegar increased according to the initial alcoholic content applied. The high-acidity vinegar produced by fed-batch culture at an IAC of 6-7% showed improved physicochemical and volatile properties as compared to the moderate-acidity vinegar.

Physicochemical Quality and Luminescence Characteristics of Gamma-irradiated Dried Fish Products

Eun-Joo Park, Han-Na Jang, Deokjo Jo, Gui-Ran Kim, and Joong-Ho Kwon*School of Food Science and Biotechnology, Kyungpook National UniversityAbstract Dried fish products, such as seasoned cuttlefish, anchovy, and filefish, were analyzed to investigate thephysicochemical quality and luminescence properties following gamma-irradiation. The overall color difference slightlyincreased in all irradiated samples, showing significant changes in Hunter’s L, a, and b color values. Cuttlefish and filefishshowed higher values in hydrophilic browning, whereas anchovy showed a higher value in lipophilic browning. The browncolor intensity of filefish showed a dose-dependent increase. The thiobarbituric acid (TBA) value significantly increased inirradiated samples of cuttlefish and anchovy, which have relatively high lipid contents. Irradiated samples, except anchovy,were not suitable for screening using photostimulated luminescence (PSL) because only negative or intermediate valueswere observed. Thermoluminescence (TL) measurements were suitable for all fish samples, i.e., irradiation-specific glowcurves were obtained, signal intensity increased, and the TL ratio fulfilled the criterion. There was no significant differenceamong the irradiated samples with regard to the sensory properties.Keywords: cuttlefish, filefish, anchovy, gamma irradiation, luminescence