ABSTRACT The objective of this study was to assess the sensitivity of the castor bean cultivar “BRS 188 Paraguaçu” to available soil water for plants and soil organic matter content based on their effects on fruit yield and seed oil content. A 2 × 4 factorial experiment was conducted from October 2008 to March 2009 under field conditions using randomized complete block design; two soil organic matter contents (5.0 and 25.0 g·kg−1) and four available soil water levels for plants at the irrigation time (70, 80, 90, and 100% of the total available soil water) with three replicates were tested. On each experimental unit measuring 100 m2, 50 plants were cultivated with a spacing of 2 m × 1 m (24 useful and 26 border plants). Analysis of variance (F test) was performed; qualitative factors (soil organic matter) were compared by Tukey's test and quantitative factors (available soil water) by regression analysis. Increased soil organic matter and available soil water for plants substantially increased productivity; however, seed oil content, mean 100-seed mass, mean 100-fruit mass, and seed:fruit ratio were affected by available soil water content alone. Therefore, the tested cultivar is sensitive to reduced available soil water content, which severely decreases its productivity.

The phytochemical study of Hippeastrum goianum led to the identification of 13 compounds by means of gas chromatography-mass spectrometry (GC-MS) and nuclear magnetic resonance (NMR). Compounds 7-demethoxy-9-O-methylhostasine (1) and 7-deoxi-trans-dihydronarciclasine (2) had their absolute configurations determined by vibrational circular dichroism (VCD). This is the first time that compound 1 is described in the Amaryllidaceae family. The cytotoxicity of all isolated compounds was tested against colorectal carcinoma (HCT 116), breast carcinoma (MCF-7), and non-tumor human retinal pigment epithelium (RPE) cell lines. The half-maximum inhibitory concentration (IC50) of compound 2 against each cell line was equivalent to the positive control (doxorubicin), indicating a considerable cytotoxic activity.

Aroma is one of the most important sensory attributes for acceptance by beef consumers. The first step in analysing the volatile compounds associated with this attribute is their extraction from the food matrix, solid-phase microextraction has been widely used for volatile compound determination in meat. This study aimed to test six different solid-phase microextraction (SPME) fibre coating materials for their volatile compounds extraction efficiency for roasted beef and to optimize the extraction conditions using response surface methodology. Gas chromatography coupled with a flame ionization detector (GC-FID) and mass spectrometry (GC-MS) were used. The choice of SPME fibre coating was based in the total area obtained by GC-FID analysis for the six fibre coatings. The optimum time and temperature for SPME extraction was 60 ºC/65 minutes. The mixed-phase fibre coatings showed the best results for extracting volatile compounds in roasted beef as higher number of compounds were identified. The carboxen/polydimethylsiloxane (CAR/PDMS) fibre extracted the largest number of compounds under the optimum extraction condition. Aldehydes were the predominant class of compounds found in roasted beef, followed by alcohols and hydrocarbons.