DECOMPOSITION OF TURMERIC CURCUMINOIDS AS AFFECTED BY LIGHT,SOLVENT AND OXYGEN1

Turmeric curcuminoids are important natural pigments but their instability limits their use in many foods. This study was conducted to examine light-induced degradation of turmeric curcumin as affected by solvent system and oxygen. The rate constants and half-lives were determined for purified curcumin, demethoxycurcumin and bis-demethoxycurcumin exposed to 1450 lux using reversed-phase HPLC. Rates of degradation of each pigment followed first-order kinetics. Differences in rate constants and half-lives between the individual pigments were minor in an acetic acid-NaCl solution; however, in methanol, large differences in stability to light of the individual pigment were observed. Stability of all the pigments to light was several fold greater in methanol than in acid brine. In methanol sparged with air, stability to photooxidation was curcumin > demethoxycurcumin > bis-demethoxycurcumin. In methanol, curcumin was more stable than the other curcuminoids when sparged with air than when sparged with nitrogen. In methanol sparged with nitrogen, demethoxycurcumin was the most stable pigment. All of the pigments were stable in the dark.     

Assessing the Assessments: Improving Methodologies for Impact Assessment in Transboundary Watercourses

Transboundary impact assessment (TIA) has become an important environmental management tool, particularly where a project may have transboundary impacts. With the growing practice of TIA, it becomes important to consider the accuracy of the transboundary impact assessments that are being conducted. If TIA is a planning tool designed to provide a basis for making an informed decision, does it actually provide the necessary information? This paper summarizes lessons learned in pilot testing a methodology to assess the accuracy of TIAs.     

ffect of Initial Fat Level and Cooking Method Cholesterol Content and Caloric Value of Ground Beef Patties

Ground beef patties were formulated to contain 0, 5, 10, 15, 20, 25 or 30% fat. The patties were either broiled or pan-fried for a predetermined time, then frozen. A sample from each treatment was thawed and reheated by a microwave oven and then refrozen. Fat, moisture, protein, ash, and cholesterol content, were determined for patties from each treatment. Cholesterol content of cooked patties was not related (P>0.05) to initial fat content. Caloric content of cooked patties was curvilinearly related to fat content of original (raw) patties due to the increased loss of fat during cooking as initial fat level increased.     

Improved Method for Determination of Salt in Oysters by Direct Titration of Chloride Ion

Determination of salt in oysters by direct titration of the chloride ion, using 0.171N silver nitrate and dichlorofluorescein as an indicator, was compared to the AOAC back titration procedure. The direct titration method was easier to perform and far more rapid than the AOAC procedure and could be done in-plant. No significant differences were observed between the methods; however, the direct titration method was more reproducible at salt concentrations of less than 0.5%. The standard deviations were much greater for the AOAC procedure at low salt concentrations but were similar at higher salt concentrations.     

Influence of Sintering Temperature on Intrinsic Trapping in Zinc Oxide-Based Varistors

The ac electrical data of the ZnO-Bi₂O₃ varistor system, in the frequency range 5 Hz to 13 MHz, when analyzed in the complex capacitance ( C *) plane, yields a distinct depressed semicircular relaxation having an average time constant on the order of 10⁻⁶ s. This trapping is attributed to the possible formation of ionized intrinsic/native defects. The decrease in the depression angle and average relaxation time, monitored as a function of the increasing sintering temperature (≥1100°C), indicated an improvement in the degree of uniformity in the loss-conductance and rapidity of response of the intrinsic trapping. The dependence of the ac parameters related to this trapping response obtained from the C * plane on the sintering temperature has been presented.     

Hydrolysis in the Aluminum sec-Butoxide—Water—Isopropyl Alcohol System: II, Aging and Microstructure

Solutions representing a wide range of compositions in the aluminum sec -butoxide-water-isopropyl alcohol system were prepared. Solutions were mixed at room temperature, then gelled and evaporated at 80°C. Regions within this system were distinguished where translucent gels formed instead of precipitates or powders. Translucent gels formed in compositions with high water content and high isopropyl alcohol content. The stages of sol-gel process were investigated by Fourier transform infrared spectroscopy in the early stages and in gels before and after solvent evaporation. The microstructure was characterized by nitrogen sorption analysis.     

Adulterants in Whiskey: Detection and Identification by Principal Component Analysis

Model adulterants such as gasoline, phenol, rubber hose, and hair were added to whiskies to prepare adulterated samples. Methylene chloride extracts of these and of the unadulterated whiskies were separated by capillary column GC. Principal Component Analysis was applied to the gas chromatograms, and the resulting scores were used to decide upon product acceptability. Using a series of standards, scores were also the basis for identification of adulterants in rejected samples. In the largest of three data sets, decisions were correct for over 95% of samples, and all adulterated samples were correctly identified.