Composition of volatile compounds in bovine milk heat treated by instant infusion pasteurization and correlation to sensory analysis

Volatile compounds in skim milk and nonstandardised milk subjected to instant infusion pasteurisation at 80°C, 100°C and 120°C were compared with raw milk, high temperature short time pasteurised milk and milk pasteurised at 85°C/30 s. The composition of volatile compounds differed between infusion pasteurisation treated samples and the reference pasteurisations. The sensory properties of skim milk subjected to instant infusion pasteurisation were described by negative attributes, such as cardboard sour and plastic flavours, which are not associated normally with fresh milk. Partial least squares modelling showed good correlation between the volatile compounds and the sensory properties, indicating the predictive and possible causal importance of the volatile compounds for the sensory characteristics

Microfibers for juice analysis by solid-phase microextraction.

In view of the interest in analyzing volatile compounds by SPME, the following five microfibers were tested, polydimethylsiloxane; polyacrylate; polydimethylsiloxane/divinylbenzene; carboxen/polydimethylsiloxane, and carbowax/divinylbenzene, to select the one which presents the best performance for the adsorption of the volatile compounds present in the headspace of acid lime juice samples. Sample stabilization time variations (30 and 60 minutes) were assessed as well the addition of NaCl to the samples. It was verified that the chromatogram with the most adsorbed volatile compounds was obtained with PDMS/DVB microfiber at 30 minutes and the addition of 0.2 g NaCl

Potential of derived lunar volatiles for life support

The lunar regolith contains small quantities of solar wind implanted volatile compounds that have vital, basic uses for maintaining life support systems of lunar or space settlements. Recent proposals to utilize the helium-3 isotope (He-3) derived from the lunar regolith as a fuel for fusion reactors would result in the availability of large quantities of other lunar volatile compounds. The quantities obtained would provide the annual life support replacement requirements of 1150 to 23,000 inhabitants per ton of He-3 recovered, depending on the volatile compound. Utilization of the lunar volatile compounds for life support depends on the costs, in terms of materials and energy, associated with their extraction from the lunar regolith as compared to the delivery costs of these compounds from Earth resources. Considering today's conservative estimated transportation costs ($10,000 dollars per kilogram) and regolith mining costs ($5 dollars per ton), the life support replacement requirements could be more economically supplied by recovering the lunar volatile compounds than transporting these materials from Earth resources, even before He-3 will be utilized as a fusion fuel. In addition, availability of lunar volatile compounds could have a significant cost impact on maintaining the life support systems of the space station and a Mars base

Determination of volatile compounds of the first rose oil and the first rose water by HS-SPME/GC/MS techniques

Background: Rose water and rose oil are used in the perfume, cosmetic, pharmaceutical and food industries. The determination of volatile compounds in rose oil and rose water obtained from oil-bearing rose is highly important in terms of availability in the industry and in human health.Materials and Methods: Twenty four and twenty six volatile compounds were determined in the first rose oil and in the first rose water. Thus, in this study, volatile compounds in the first rose oil and first rose water have been determined by HS-SPME/GC/MS (Headspace-Solid Phase Micro Extraction/Gas Chromatography Mass Spectrometry) techniques which were not published previously for determining volatile compounds in rose oil and rose water.Results: Twenty four and twenty six volatile compounds were found in the first rose oil and in the first rose water, respectively. It was further discovered that both first rose oil and first rose water are rich in oxygenated monoterpenes and sesquiterpenes, with a third group of volatile compounds known as aliphatic hydrocarbons being found only in first rose oil. Citronellol contents of the first rose oil and rose water were found to be 43.40% and 40.13% respectively, whereas geraniol contents were 11.81% and 15.97%, respectively.Conclusion: These findings suggest that HS-SPME/GC/MS is a suitable technique for the determination of volatile compounds of rose oil and rose water.Keywords: Oil-bearing rose, Rosa damascena, HS-SPME/GC/MS, volatile compounds

Changes in flavour and texture during the ripening of strawberries

The amount of total volatile compounds, total acidity, total sugar content (degrees Brix) and fruit firmness were used to characterize the degree of ripeness of three strawberry varieties (Carezza, Darselect and Marmolada). A novel concept using solid phase microextraction (SPME) and measurement of total volatile compounds to distinguish between various stages of strawberry ripeness was applied. The carboxene/polydimethylsiloxane SPME fibre was found to be best suited to differentiate between the stages of ripeness. The amount of total volatile compounds rapidly increased near to maturity (between the three-quarters red stage and the dark-red stage). Most of the volatile compounds identified were esters, followed by aldehydes, and alcohols. The most abundant volatile compounds were propyl butanoate, 3-phenyl-1-propanol, butyl butanoate, isobutyl butanoate, 3-methyl butyl butanoate and isopropyl hexanoate. The concentration of green aroma components such as hexanal, trans-2-hexenol and cis-3-hexenyl acetate progressively decreased during the maturation process until they became minor components in mature strawberrie

Biologically produced volatile compounds: N2O emissions from soils

Tropospheric nitrous concentration has increased by 0.2 0.4% per year over the period 1975 to 1982, amounting to net addition to the atmosphere of 2.8 - 5.6 Tg N2O-N per year. This perturbation, if continued into the future, will affect stratospheric chemical cycles, and the thermal balance of the Earth. In turn it will have direct and indirect global effects on the biosphere. Though the budget and cycles of N2O on Earth are not yet fully resolved, accumulating information and recent modelling efforts permit a more complete evaluation and better definition of gaps in our knowledge

The Effects of Roasting Time of Unfermented Cocoa Liquor Using the Oil Bath Methods on Physicochemical Properties and Volatile Compound Profiles

This study aimed to measure the effect of roasting time on physicochemical properties and volatile compounds of unfermented cocoa liquor roasted with an oil bath method. Physicochemical properties (pH, temperature, and color), flavor, and volatile compounds were analyzed. The results showed that the longer the roasting time the higher the unfermented cocoa liquor’s temperature, °Hue, and ΔE value, but lower pH and L value. There were 126 volatile compounds obtained by various roasting time, identified as pyrazines (12), aldehydes (16), esters (1), alcohols (31), acids (15), hydrocarbons (11), ketones (19), and others (21). At 15, 20, and 25 minutes of roasting time, 69, 74, and 67 volatile compounds, respectively, were identified. Volatile compounds’ profiles were indicated to be strongly influenced by roasting time. The largest area and highest number of compounds, such as pyrazines and aldehydes, were obtained at 20 minutes, which was also the only time the esters were identified. As well as the time showed a very strong flavor described by panelists