Kyu-Seob Chang

Taste and flavor compounds in box thorn (Lycium chinense Miller) leaves

Abstract Contents of selected taste components in box thorn leaves collected at different seasons (from mid-May to mid-October) were determined. Volatile flavor compounds in the box thorn leaves were extracted using a simultaneous steam distillation-extraction apparatus, and the compounds were isolated and identified by gas chromatography/mass spectrometry. Box thorn leaves contained fructose (0.58–1.54%), glucose (0.33–1.33%), sucrose (0.23–0.68%) and maltose (0.60–0.98%). Non-volatile organic acids identified were citric acid (162.3–361.3 mg%), oxalic acid (61.1–130.9 mg%), malonic acid (44.9–59.4 mg%), malic acid (15.6–34.3 mg%), succinic acid (3.7–5.1 mg%), fumaric acid (1.3–2.9 mg%), and lactic acid (0.0–1.1 mg%). Eighteen free amino acids were found in the leaves and their contents varied greatly with season. Proline (52.6–267 mg%), histidine (162–244 mg%) alanine (99.5–198 mg%), leucine (51.4–149 mg%), valine (54.5–125 mg%), isoleucine (37.0–119 mg%) and aspartic acid (46.7–111 mg%) were major amino acids in the leaves. Total tannin contents were 0.90–2.10%, showing the highest amount in October. Forty-five volatile flavor components were identified in the leaves for the first time. These included four acids, 15 alcohols, seven aldehydes, two esters, three furans, nine hydrocarbons, two ionones, and three other compounds.

Rheological, surface and colorbvietric properties of egg albumen gel affected by pH

Abstract Studies were conducted to evaluate the effects of albumen at naturally existing pH ranges on the functional and gel characteristics. Albumen was obtained from freshly laid shell eggs. The pH of albumen was altered using either IN NaOH or IN HC1 to obtain a pH of 7.5, 8.0, 8.5, 9.0, 9.5 and 10.0. The altered albumen was tested for its foaming capacity (FC), foam stability (FS), and bake volume (BV). Albumen gels were prepared and tested for firmness (FM), strain at failure (NF), and stress at failure (SF) as well as their color attributes (Hunter L, a, and b). In general, FC and BV of the albumen decreased (P<0.05) as the pH increased. The BV of the albumen was affected by FS than FC for all the adjusted pH ranges. A denser structure was observed for albumen gels as the pH increased. The FM, NF and SF of albumen gels increased, and Hunter L and a values decreased with the increasing adjusted pH. The FM, NF, SF and Hunter L value of albumen gel could be used as quality indicators in evaluating the ...