True Density Prediction of Garlic Slices Dehydrated by Convection.

Physiochemical parameters with constant values are employed for the mass-heat transfer modeling of the air drying process. However, structural properties are not constant under drying conditions. Empirical, semi-theoretical, and theoretical models have been proposed to describe true density (ρp). These models only consider the ideal behavior and assume a linear relationship between ρp and moisture content (X); nevertheless, some materials exhibit a nonlinear behavior of ρp as a function of X with a tendency toward being concave-down. This comportment, which can be observed in garlic and carrots, has been difficult to model mathematically. This work proposes a semi-theoretical model for predicting ρp values, taking into account the concave-down comportment that occurs at the end of the drying process. The model includes the ρs dependency on external conditions (air drying temperature (Ta)), the inside temperature of the garlic slices (Ti ), and the moisture content (X) obtained from experimental data on the drying process. Calculations show that the dry solid density (ρs ) is not a linear function of Ta, X, and Ti . An empirical correlation for ρs is proposed as a function of Ti and X. The adjustment equation for Ti is proposed as a function of Ta and X. The proposed model for ρp was validated using experimental data on the sliced garlic and was compared with theoretical and empirical models that are available in the scientific literature. Deviation between the experimental and predicted data was determined. An explanation of the nonlinear behavior of ρs and ρp in the function of X, taking into account second-order phase changes, are then presented.

Transformed cell suspension culture of Galphimia glauca producing sedative nor-friedelanes.

The Mexican species GALPHIMIA GLAUCA (Cav.) Kuntze (Malphigiaceae) synthesises a family of sedative and anxiolytic nor-secofriedelanes, designated as galphimines. These active principles accumulate at low concentration in the aerial parts of plants from wild populations. Transformed calluses and cell suspension cultures of this species were established in order to induce a greater production of nor-friedelanes. The cell suspension line GgBa was selected and grown over a period of two years of continuous subculturing in MS nutrient medium in the absence of growth regulators. PCR and Southern blot analyses were employed in order to confirm that the ROL A gene had been integrated into the plant genome. Batch cultures of the GgBa cell line were grown over a 32-day period and first-order growth kinetics was observed, reaching a specific growth rate (micro) of 0.13 d (-1). The production of glaucacetalin A ( 10), a triterpenoid related to the known galphimines, was quantified in the nutrient medium by HPLC. The transformed cell suspension culture GgBa also synthesised a novel nor-friedelane, given the name glaucacetalin D ( 13). High-resolution spectroscopic and spectrometric techniques were employed to elucidate the structure of 13. This triterpene has never been observed in wild plant tissues or in other IN VITRO cultures. Maslinic acid ( 14) was identified in cell biomasses. The triterpene production of the cell line GgBa was as follows: glaucacetalin A, 2.7 mg/L; glaucacetalin D, 2.9 mg/L and maslinic acid, 2.4 mg/g dry weight. The sedative activity of compounds 10 and 13 was demonstrated in ICR mice by using the sodium pentobarbital-induced hypnosis model. No cytotoxicity of 10 and 13 was exhibited against KB, MCF-7 and HF6 human cancer cell lines.