The retrogradation of 5, 10, 15, and 25% corn starch gels was measured using differential scanning calorimetry (DSC), rheology, and an array of NMR spectroscopy techniques. During the initial (<24 h) stage of retrogradation, an increase in G' corresponding to an increase in the number of solid protons participating in cross-relaxation (M(B)(0) was observed for all four concentrations studied. During the latter (>24 h) stage of retrogradation, amylopectin recrystallization becomes the dominant process as measured by an increase in deltaH(r) for the 25% starch gel, which corresponded to a further increase in. A decrease in the molecular mobility of the liquid component was observed by decreases in (17)O T(2), (1)H D(0), and T(2A). The value for T(2B) (the solid transverse relaxation time) did not change with concentration or time indicating that the mobility of the solid component does not change over time despite the conversion of the highly mobile starch fraction to the less mobile solid state during retrogradation.

The anthocyanins from Ajuga pyramidalis Metallica Crispa cell cultures were characterized by a combination of HPLC, chemical hydrolysis, MS, and 1H NMR. Chromatographic analysis of the in vivo and in vitro samples showed the same suite of anthocyanins and relative composition. Chemical hydrolysis and mass spectral analysis of the major pigment from suspension cultures showed the presence of cyanidin, three glucoses, two ferulic acids, and malonic acid. The structure of the major pigment in the suspension cultures was determined to be 3-O-(6-O(E)-ferulyl)-2-O-[(6-O(E)-ferulyl)-β-d-glucopyranosyl-β-d-glucopyranosyl]-5-O-(6-O-malonyl)-β-d-glucopyranosylcyanidin. The anthocyanins in the in vitro extract were more stable toward light compared to those in the in vivo extract. The initial degradation of the major pigment both from in vitro and in vivo sources was mainly due to demalonylation. Keywords: Ajuga; anthocyanins; cell culture; stability-anthocyanins

An examination of the methods for nuclear magnetic cross-relaxation spectroscopy (CRS) data collection and analysis was conducted using water and an aqueous waxy corn starch suspension to better perform and interpret the results obtained using CRS. The CRS data collection properties evaluated were the time to achieve steady state saturation, the direct saturation of liquid protons, generation of transverse magnetization, and dependence of the offset frequency and radio frequency (RF) field strength of longitudinal relaxation in the presence of RF saturation. Effects were evaluated for variations of input values of RF saturation field strength, apparent cross-relaxation rate, and solid longitudinal relaxation rate on the results for solid content and solid internal mobility from fitting NMR data to modified theoretical expressions. Discrepancies between fitted and stoichiometric values for the solid to liquid proton ratio were investigated. The fitting procedure used a Gaussian line shape for RF saturation of the solid-like spin system and a Lorentzian line shape for RF saturation of the liquid-spin system. Conditions under which acceptable results can be obtained with limited data sets are discussed.