Identification of volatiles and odor-active compounds of aromatic rice by OSME analysis and SPME/GC-MS.

During cooking, aromatic rice has a pleasant and characteristic aroma, a relevant factor to add sale value and attract consumer interest. This work studied the volatile compounds of aromatic rice (IAC 500) aiming at identifying those responsible for the aroma and flavor of the cooked rice. The description of the aromatic notes of the IAC 500 rice was carried out by a trained and selected sensory panel, followed by olfactometry (OSME) and identification by GC-MS of the rice volatile compounds extracted by SPME. A total of 80 volatiles was sensorially perceived and/or detected in the chromatographic effluent, of which 65 were identified, 44 presented some odor, and 36 were odorless. Among the odorous compounds, 15 were not detected by GC-FID or GC-MS. This study confirmed the compound 2-acetyl-1-pyrroline as the impacting volatile compound to the aroma of aromatic rice since it presented a very low percentage of area in the chromatogram and a high odor intensity. Other 43 compounds presented odor in lower intensities, but also contributed to the overall aroma of IAC 500 rice. From the 11 aromatic notes mentioned by the trained panel (cooked vegetable/seed, corn, hominy, green, porridge, popcorn, fresh baked cake/bread, milk, caramel, tapioca flour and flower), eight were related to the volatile compounds responsible for their aroma.

Aroma profile of rice varieties by a novel SPME method able to maximize 2-acetyl-1-pyrroline and minimize hexanal extraction.

The solid phase microextraction (SPME) has been the most used technique for the extraction of volatile compounds from rice because of its easy operation and solvent-free. The extraction parameters, sample mass and incubation temperature, were optimized through a central composite rotational design (CCRD), aiming at maximizing the extraction of 2-acetyl-1-pyrroline (2AP), the main compound responsible for the aroma in aromatic rice, and minimizing the generation of hexanal, a marker of lipid oxidation. Besides, the time of sample incubation and fiber exposure for the extraction of the volatile compounds from rice were determined. The optimized conditions for SPME were: 2.5 g of ground rice in a 20 mL vial, sample incubation at 80 °C for 60 min and exposure of the divinylbenzene/carboxene/polydimethylsiloxane (DVB/CAR/PDMS) fiber in the headspace for 10 min. The optimized method was sucessfuly applied to 12 varieties of rice and principal component analysis (PCA) was performed to observe similarities in their volatile profile. A total of 152 volatile compounds were identified among the different rice varieties. From these, 42 were identified in arborio rice, 47 in basmati brand A, 43 in basmati brand B, 55 in black rice, 63 in brown rice, 39 in jamine rice, 50 in parboiled brown rice, 43 in parboiled rice, 54 in red rice, 63 in sasanishiki rice, 46 in white rice and 70 in wild rice.

Potential of volatile compounds produced by fungi to influence sensory quality of coffee beverage.

Fungi are known producers of a large number of volatile compounds (VCs). Several VCs such as 2,4,6 trichloroanisole (TCA), geosmin and terpenes have been found in coffee beverages, and these compounds can be responsible for off-flavor development. However, few studies have related the fungal contamination of coffee with the sensory characteristics of the beverage. The aim of this research was to investigate the production of VCs by fungi isolated from coffee and their potential as modifiers of the sensory coffee beverage quality. Three species were isolated from coffee from the southwest of São Paulo state and selected for the study: Penicillium brevicompactum, Aspergillus luchuensis (belonging to section Nigri) and Penicillium sp. nov. (related to Penicillium crustosum). VCs produced by the fungal inoculated in raw coffee beans were extracted and tentatively identified by SPME-GC-MS. Different VCs that may interfere in the coffee beverage quality were detected in the raw coffee beans inoculated with these fungal species (mainly A. luchuensis). Oct-1-en-3-ol was detected in the raw coffee inoculated with A. luchuensis. This compound, which is characterized by earthy and moldy/mushroom aroma, can be related to negative characteristics of coffee beverage in sensory analysis. On the other hand, the presence of some fungal species in the coffee, even at a high percentage of infection, did not necessarily result in loss of the sensorial quality of the beverage, since the samples with a high infection of P. brevicompactum showed positive sensory evaluation.

New data on the total lipid, cholesterol and fatty acid composition of raw and grilled beef longissimus dorsi

Simultaneous analyses of total lipids, cholesterol and fatty acids were carried out on raw and grilled beef longissimus dorsi trimmed of external fat. Cholesterol was determined by high performance liquid chromatography and the fatty acids by gas chromatography. Mean total lipid (g/100 g) ranged from 2.1 to 2.6 for raw beef and 3.5 to 4.0 for grilled beef steaks. Cholesterol levels (mg/100 g) ranged from 40 to 43 for raw beef and 67 to 70 for grilled beef steaks. The main intramuscular fatty acids of the raw and grilled meat were 14:0, 16:0, 16:1n7, 18:0, 18:1n9, 18:1n7 and 18:2n6. Grilled lean beef steaks had significantly higher contents of the principal fatty acids and most of the minor fatty acids. The higher values for the three components in the grilled meat were due to loss of moisture during grilling. There was no significant difference between the apparent and true retentions values, both indicating no significant loss or degradation of total lipids, cholesterol and fatty acids during grilling.

[Effect of eggplant on plasma lipid levels, lipidic peroxidation and reversion of endothelial dysfunction in experimental hypercholesterolemia]. / Efeito da berinjela sobre os lípides plasmáticos, a peroxidação lipídica e a reversão da disfunção endotelial na hipercolesterolemia experimental.

PURPOSE: To study the effect of egg plant on endothelium-dependent relaxation, and plasma lipids in hypercholesterolemic rabbits, and to assess influence of this plant on the malondialdehyde (MDA) content of LDL particles and the arterial wall. METHODS: Thirteen male rabbits were randomly assigned to control (C), hypercholesterolemic (H) and egg plant (E) treated groups (n = 10 each). The H and E rabbits were fed a diet supplemented with cholesterol (0.5%) and coconut oil (10%) for 4 weeks. In addition, group E received 10 mL of the fruit juice/day during the last 2 weeks. The animals were killed and the aorta removed to measure MDA content and the endothelium dependent relaxation responses. Total plasma cholesterol, VLDL, LDL, HDL and triglyceride levels were determined using commercial kits. MDA was quantified in native and oxidized LDL and in the arterial wall. RESULTS: After 4 weeks, the E group rabbits had a significantly lower weight, plasma cholesterol, LDL, triglyceride and aortic cholesterol content than group H(p < 0.05). The MDA content that was significantly increased in the LDL particles and in the arterial wall of H rabbits was reduced in the E group (p < 0.05). Endothelium-dependent relaxation were significantly higher in the E group compared H group rabbits (p < 0.05). CONCLUSION: In hypercholesterolemic rabbits egg plant juice significantly reduced weight, plasma cholesterol levels, aortic cholesterol content and the MDA concentrations in native-oxidized LDL and in the arterial wall and increased the endothelium-dependent relaxations.