Total Aldehydes Research Articles

Chemical and sensorial changes of Croatian monovarietal olive oils during ripening

AbstractThe aim of this investigation was to determine the impact of fruit ripening on chemical and sensorial changes in monovarietal olive oils obtained from two important olive cultivars grown in Croatia, Buža and Črna. In Buža oils peroxide value, K232 and K270 increased during ripening, while no differences among three ripening stages in Črna oils were observed. Oils of both cultivars at the later ripening stages had higher free acidity level and lower sensory score followed by mild loss in almost all positive sensory characteristics. Total phenols and antioxidant capacity decreased in Buža oils during fruit ripening, while in Črna oils reached maximum level in purple stage and then progressively decreased in the black ripening stage. Oleic acid level slightly increased during ripening in both cultivar oils. Linoleic acid decreased in Buža oils obtained from black fruits while palmitic acid decreased in Črna oils during ripening. In both monovarietal oils chlorophyll and carotenoids concentrations decreased during ripening. The two cultivars had different course of total aldehydes, total esters and total ketones during ripening, while total alcohols were the highest in oils from purple ripening stage and then decreased as ripening progress.Practical applications: During the ripening, the chemical composition of olive fruit changes influencing the quality grade, oxidative stability, sensory characteristics and nutritional value of the obtained products. The cultivars characterized by a similar trend of ripening process could have different course of chemical and sensorial changes in oil during fruit ripening. Therefore, knowledge about these changes is important for determination of proper harvest time of single cultivar to achieve optimum of its potential regarding desirable characteristics of obtained oil.

Modeling and process evaluation of membrane bioreactor for removing biodegradable organic matter from water

A membrane bioreactor (MBR) process was employed for removing biodegradable organic matter (BOM) and ozonation disinfection byproducts (DBPs) exemplified by total aldehydes from ozonated potable water. The BOM removal was to prevent or reduce microbial regrowth in water distribution systems and to reduce DBP forming potential after ozonation. A mathematical modeling approach was used as a tool for performance prediction and process design with implication to process upscaling. The modeling protocol integrated adsorption and biodegradation in liquid and adsorbent phases with model parameters obtained from independent experiments. The BOM was expressed as biodegradable dissolved organic carbon (BDOC), assimilable organic carbon (AOC), and total aldehydes. The MBR studies demonstrated the process effectiveness in removing AOC, BDOC and total aldehydes, and validated the model's predictive capability. Sensitivity studies qualitatively evaluated parameters influencing process dynamics. The simulation studies were unique in examining shutdown and startup effects on process dynamics and process recovery.

Effect of Fermentation Containers and Raw Materials on Chemical Composition and Sensory Quality of fermented cereals

Effect of fermentation containers (plastic, wooden and earthen), cereals (millet, rice, maize and wheat) and cereal combinations (millet, rice and wheat) on chemical and sensory quality of fermented cereals were studied. Fermentation was carried out for 15 days at 26±2 ºC using defined starter made from S. cerevisiae and R. oryzae in rice flour. Finger millet fermented in plastic container had higher alcohol content (15.81% v/m) and TSS (11.96 ºBx) than that of earthen container while moisture and fixed acid contents remained unaffected. Total esters (1.813 g/l alc), total aldehyde (0.850 g/l alc), total acidity (1.58% m/m) and volatile acidity (0.296% m/m) were higher in millet fermented in earthen container. Fermentation containers had no significant (p>0.05) effect on the taste and smell of millet jand but color was comparatively superior in plastic container. Total ester (31.1 mg % m/v), TSS (3.97 ºBx), pH (4.67), total acid (0.41% m/v)) and fixed acid (0.37% m/v) contents were significantly higher in wheat jand compared to millet, rice, and maize jands, whereas no noticeable difference in volatile acidity (0.02 – 0.048% m/v) and alcohol (5.53 – 6.20% v/v) contents were found among four jands. Sensory evaluation showed that taste and smell of rice jand were superior (liked very much) while that of maize was rated as dislike slightly by the panelists. Addition of rice significantly increased the TSS of fermented millet while total acidity, fixed acidity and alcohol contents were not affected by cereal combinations. Addition of wheat decreased the ester content (0.431 g/l alc) to that of control (100% millet) (0.863 g/L alc). Total aldehyde content was significantly increased by both rice and wheat addition with a maximum value of 1.545 g/l alc in 20% rice added fermented millet. Finger millet substituted with 20% of rice had the maximum fusel oil (9.370 g/l alc) while a minimum value of 5.297 g/l alc was found in 20% wheat substituted fermented millet. Cereal combination did not have significant effect on methanol content and the values were in the range of 2.346 – 3.858 g/L alc. Addition of rice significantly increased the reducing and total sugar contents while 20% wheat addition decreased both the reducing and total sugar contents in fermented millet. Sensory evaluation revealed that cereal combination did not affect the color preference of jands, whereas addition of wheat significantly impaired the taste and smell of jand.DOI: http://dx.doi.org/10.3126/njst.v12i0.6521 Nepal Journal of Science and Technology 12 (2011) 330-339

Transverse approach between real world concentrations of SO2, NO2, BTEX, aldehyde emissions and corrosion in the Grand Mare tunnel

With regard to automotive traffic, a tunnel-type semi enclosed atmosphere is characterized by a higher concentration of gaseous pollutants than on urban traffic roads and highlights the gaseous effluent species having an impact on material degradation. Therefore, a transverse approach between air quality and its consequences upon the longevity of materials is necessary, implying better knowledge of tunnel atmosphere and a better understanding of material degradation inside a tunnel for operating administration. Gaseous pollutant measurements carried out in a road tunnel in Rouen (Normandy) give the real world traffic concentrations of experimental exposure conditions. The sampling campaigns, achieved in summer and winter include SO2, NO2, BTEX and aldehyde analyses. Effluent profiles in the upward and downward tubes have been established. The current work shows that SO2, NO2, formaldehyde, acetaldehyde, propanal and butanal must be considered in the degradation process of materials in a stuffy environment. As regards NO2, its concentration depends on the modification of the automotive fleet. The total aldehyde concentrations indicate no particular trend between the two bores. Formaldehyde, acetaldehyde, propanal, butanal and acrolein species are the most abundant species emitted by vehicles and represent 90% to 95% of the total aldehyde emissions.

Catalyzed Ozonation Decomposition of Taste and Odor-Causing Substances in Water and Simultaneous Control of Aldehyde Generation

Ozone oxidation is commonly used to remove taste and odor (T&O) from drinking water. However, this technique is only moderately effective, and is complicated by the formation of aldehyde by-products. In this study, we investigated the efficiency of ozonation with which aluminum oxide catalysts (γ-AlOOH [HAO], γ-Al2O3 [RAO], and α-Al2O3 [AAO]) removed three representative odorous substances (2-methylisoborneol [MIB], 2,4,6-trichloroanisole [TCA], and 2-isopropyl-3-methoxypyrazine [IPMP]) from water and reduced the yields of aldehydes. Application of ozonation alone led to incomplete mineralization of odorous substances and generation of large amounts of aldehydes. In comparison, catalyzed ozonation by the three aluminum oxides substantially increased the removal efficiencies of T&O and reduced the production of aldehydes, albeit to different degrees. In all forms of ozonation, the main aldehyde products were formaldehyde, acetaldehyde, propionaldehyde, n-butyraldehyde, glyoxal, and methylglyoxal. HAO satisfactorily catalyzed the ozone oxidation of TCA and IPMP and effectively reduced the total aldehyde production during their oxidation. Catalyzed ozonation by AAO could not effectively reduce total aldehyde production during the oxidation of TCA and IPMP, which resulted in incomplete removal of T&O from water. Catalyzed ozonation by RAO provided the best results in removing MIB, TCA, and IPMP and reducing total aldehyde production.

Monitoring by 1H nuclear magnetic resonance of the changes in the composition of virgin linseed oil heated at frying temperature. Comparison with the evolution of other edible oils

Linseed oil was heated at frying temperature in an industrial fryer for 20 h. The evolution of its composition was monitored by 1H Nuclear magnetic resonance. The composition parameters determined simultaneously were: the molar percentage of the different acyl groups, the Iodine Value, the concentration of the total aldehydes as well as of the different kinds of aldehydes; in addition, the percentage in weight of Polar Compounds was also determined at different heating times. When heating this oil the molar percentage of linolenic groups diminishes at an important rate while that of linoleic or diunsaturated groups increases, as does that of saturated plus modified groups, that of oleic or monounsaturated groups remaining unchanged. The main aldehydes formed were (E,E)-2,4-alkadienals together with n-alkanals and (E)-2-alkenals. This oil reached the safety limit of 25% in weight of Polar Compounds very early with a very small degradation level of acyl groups and a very low content of aldehydes. The changes undergone by this oil were compared with those of sunflower oil and of extra virgin olive oil submitted to the same degradative conditions.

Characteristics of disinfection by-products reduction in the processes of drinking water treatment system using Nakdong river water

In this study, batch and continuous experiments were conducted to investigate the influential factors on the distribution and formation of aldehydes, bromate and bromide in Nakdong river water and to investigate the behaviour of disinfection by-products (DBPs) in the processes of drinking water treatment system. The mean influent concentrations were 3.1 mg/L (2.4–3.9 mg/L) for dissolved organic carbon (DOC), 57.6 ug/L (42.0–85.7 ug/L) for total aldehydes (TA) and 55.7 ug/L (17.4–89.3 ug/L) for bromide. As a result, TA and bromide levels in the Nakdong river water increased with the decreasing water flow rate and decreasing water temperature. In pre- and post-ozonation, the DBPs concentration increased with increasing bromide level, ozone dosage and pH value. In particular, the concentration of DBPs formation in both pre-ozonation and winter was relatively higher than that in both post-ozonation and summer. In coagulation and sedimentation, polyaluminium sulphate organic magnesium coagulation resulted in slightly less DBPs removal than polyaluminium silicate chloride coagulation. TA was significantly reduced at the top of sand and biological activated carbon (BAC) filters, whereas bromate was effectively reduced in a three-month-old BAC filter.

Comparative metabolic profiling to investigate the contribution ofO. oeniMLF starter cultures to red wine composition

In this research work we investigated changes in volatile aroma composition associated with four commercial Oenococcus oeni malolactic fermentation (MLF) starter cultures in South African Shiraz and Pinotage red wines. A control wine in which MLF was suppressed was included. The MLF progress was monitored by use of infrared spectroscopy. Gas chromatographic analysis and capillary electrophoresis were used to evaluate the volatile aroma composition and organic acid profiles, respectively. Significant strain-specific variations were observed in the degradation of citric acid and production of lactic acid during MLF. Subsequently, compounds directly and indirectly resulting from citric acid metabolism, namely diacetyl, acetic acid, acetoin, and ethyl lactate, were also affected depending on the bacterial strain used for MLF. Bacterial metabolic activity increased concentrations of the higher alcohols, fatty acids, and total esters, with a larger increase in ethyl esters than in acetate esters. Ethyl lactate, diethyl succinate, ethyl octanoate, ethyl 2-methylpropanoate, and ethyl propionate concentrations were increased by MLF. In contrast, levels of hexyl acetate, isoamyl acetate, 2-phenylethyl acetate, and ethyl acetate were reduced or remained unchanged, depending on the strain and cultivar evaluated. Formation of ethyl butyrate, ethyl propionate, ethyl 2-methylbutryate, and ethyl isovalerate was related to specific bacterial strains used, indicating possible differences in esterase activity. A strain-specific tendency to reduce total aldehyde concentrations was found at the completion of MLF, although further investigation is needed in this regard. This study provided insight into metabolism in O. oeni starter cultures during MLF in red wine.

Effect of curing salt content on lipid oxidation and volatile flavour compounds of dry-cured turkey ham

Ninety green turkey hams were equally divided into 3 groups and cured with 3 g/100 g, 4 g/100 g or 5 g/100 g salt. Cured hams were then dry-ripened by following the same procedure as dry-cured pig ham with some modifications. The effect of curing salt on lipids' oxidation and volatile compounds formation by dry-cured turkey hams was studied. The TBARS values and the total content of volatile compounds in ripened turkey hams decreased significantly as salt concentration increased (p < 0.05). The amount of curing salt was positively correlated with total aldehydes content (r = 0.982), but negatively correlated with alcohols, ketones and alkanes contents (r = −0.975, −0.649 and −0.807, respectively). Principal component analysis results showed that the first principal component (PC1) was dominated by aldehydes, alkanes and some alcohols, and explained 69% of total variance. These results indicated that reduced curing salt level result in increased formation of flavour-active volatiles in dry-cured turkey hams.

Waxy fraction containing long-chain aliphatic aldehydes in virgin olive oils

Long-chain aliphatic aldehydes are natural minor components occurring in the cuticle of numerous plant species and also evidenced in virgin olive oils. The fraction containing these compounds can be isolated from the oil samples by using a solid-phase extraction silica-gel cartridge and then directly analysed by GC on a 5% diphenyl–95% dimethylsiloxane capillary column, using an on column-injection system. The proposed methodology showed that extra virgin olive oils contain long-chain aliphatic aldehydes, with even carbon-atom numbers from C22 to C30. Quantitative results, using the synthesised aldehyde C21 as internal standard, give concentrations of total long-chain aliphatic aldehydes in a variable range below 116mgkg−1, being hexacosanal (C26-al) the most abundant aldehyde. The different experimental conditions utilised during olive oil extraction processes influence the total aldehydes concentration. Besides contribution to the knowledge of the minor-component composition present in olive oil, their interest and relationship with wax esters, aliphatic alcohols and n-alkanes are discussed.

Volatile Compounds Determined by HS/GC-MS Technique in Peel and Pulp of Fig (Ficus carica L.) Cultivars Grown in Mediterranean Region of Turkey

Aromatic profile of peels and pulps of four commercial fig cultivars (‘Bursa Siyahi’, ‘Karabakunya’, ‘Sari Lop’ and ‘Sultan Selim’) from Turkey were determined first time by using Headspace Gas Chromatogropy-Mass Spectrophotometer (HS/GC-MS) technigue. In general, aldehydes and therpenes were the major volatile group responsible aroma for peels and pulps in fig fruits. Total aldehydes were higher in pulps than peel in all cultivars. However total therpenes were higher in peel rather than in pulp. Among therpenes, β-caryophyllene were the major volatile compounds found in both peel and pulp. Phenol, 2,6-bis (1,1-dimethylethyl)-4-methyl were the second important group responsible for fig aroma presented in both peel and pulp. Among aldehydes, 2-hexanal were found in high proportion only in pulp in all cultivars. The other groups responsible fig aroma were 2-furancaboxaldehyde, 5 (hydroxymethyl), benzyaldethyde, furfural and Germacrene D. α-curcumene, β-bisabolene and β-sesquiphellandrene were determined only in cv. ‘Bursa Siyahi’ peel and pulp and discriminated this cultivar from the others.

Chemometric analysis of gas chromatographic data-investigation of enological parameters of a bag-in-box white wine as affected by storage time and temperature

In this study, a bag-in-box white wine was stored at 22, 35, and 45 °C for up to 48 days to produce a series of samples that exhibited different enological parameters (absorbance at 420 nm, free SO2, total SO2, total phenol, and total aldehyde). Wine samples were extracted with dichloromethane and analyzed using gas chromatography (GC) to generate volatile fingerprints. Principal component analysis (PCA) score plots of the first three principal components showed grouping trends that were influenced by storage time and temperature. PCA loading plots revealed that changes in chemical profiles were different for wines held at different storage temperatures. Storage time could be predicted accurately by partial least squares (PLS) regression of the GC data. Coefficients of determination (R2) were >0.99, and the standard error of prediction values were 0.4, 0.5, and 1.9 days over the test period of 15, 30, and 48 days, respectively. Using the same GC data with PLS analyses, the enological parameters could be accurately predicted from GC fingerprints, except for the predictions of SO2 in a wine stored at 22 °C and total phenol in a wine stored at 45 °C. Copyright © 2011 John Wiley & Sons, Ltd.

Influence of filtration on volatile compounds and sensory profile of virgin olive oils

The influence of filtration through a hydrophilic cotton layer on volatile compounds, sensory characteristics and colour of two monovarietal oils was investigated in this study. Volatiles were evaluated using headspace solid-phase microextraction-gas chromatography. After the filtration of Buža oils only a slight increase in total alcohols was noticed. In filtered Črna oils a significant decrease of total alcohols and slight changes in total aldehydes, total ketones and total C5 volatile compounds concentration were detected. No significant influence on the sensory scores of oils, but some slight changes in sensorial profiles were noted (slightly higher intensities of sensory characteristics apple and grass, and higher values of the lightness L∗ in filtered samples). The results point to unequal filtration impact on different monovarietal oils and could be useful in developing targeted technologies for specific monovarietal oils quality improvement.

Highly Regioselective Isomerization–Hydroformylation of Internal Olefins Catalyzed by Rhodium/Tetraphosphine Complexes

AbstractA new class of substituted tetraphosphine ligands has been applied in the rhodium‐catalyzed regioselective isomerization–hydroformylation of internal olefins. The rhodium/tetraphosphine ligand system is highly effective for the isomerization and hydroformylation of 2‐alkenes to form linear aldehydes. Greater than 95% linear selectivity and up to 94% yield of the total aldehydes were obtained for 2‐pentene, 2‐hexene and 2‐octene. The catalyst system also showed high to moderate linear selectivity for the isomerization and hydroformylation of 3‐hexene, 3‐octene and 4‐octene but with slow reaction rates.

DETERMINATION OF O-METHOXYCINNAMALDEHYDE IN CASSIA OIL BY INFRA-RED SPECTROPHOTOMETRY.

Abstract The determination of o-methoxycinnamaldehyde is described, based upon an absorption measurement at 1266 cm−1 in the infra-red region of the spectrum together with the normal assay for total aldehydes. Comparison of the absorption at 1266 and 1312 cm−1 may be used qualitatively to distinguish between oils derived from the bark of Cinnamomum cassia Blume and those from the leaves and twigs.

Synthesis, Characterization and Application Polystyrene-Bound Manganese Complexes

New series polymer-bounded manganese complexes were synthesized and their potential structure was investigated. Their application in the oxidation of cumene, by atmospheric pressure of molecular oxygen in the absence of solvent catalyzed by polystyrene-bound-Mn-L (where L=2,2’-bipyridine and 1,10-phenanthroline) complexes without the use of any special oxidant or coreductant, were studied. The oxidation products 2-phenyl-2-propanol and 2-phenylpropylaldehyde were produced in 41% to 71% yield and the selectivity to total alcohol and aldehyde was 100%.

Comparison of VOC emissions between air-dried and heat-treated Norway spruce ( Picea abies), Scots pine ( Pinus sylvesteris) and European aspen ( Populus tremula) wood

Heat-treated wood is an increasingly popular decoration material. Heat-treatment improves dimensional stability of the wood and also prevents rot fungus growth. Although production of heat-treated wood has been rapidly increasing, there is only little information about the VOC emissions of heat-treated wood and its possible influences on indoor air quality. In the present study, VOC emissions from three untreated (air-dried) and heat-treated wood species were compared during a four weeks test period. It appeared that different wood species had clearly different VOC emission profiles. Heat-treatment was found to decrease VOC emissions significantly and change their composition. Especially, emissions of terpenes decreased from softwood samples and aldehydes from European aspen samples. Emissions of total aldehydes and organic acids were at the same level or slightly higher from heat treated than air-dried softwood samples. In agreement with another recent study, the emissions of furfural were found to increase and those of hexanal to decrease from all the wood species investigated. In contrast to air-dried wood samples, emissions of VOCs were almost in steady state from heat treated wood samples even in the beginning of the test.

Predicción por redes neuronales artificiales de la calidad fisicoquímica de vinagre de melaza de caña por efecto de tiempo-temperatura de alimentación a evaporador-destilador flash

It was predicted via Artificial Neural Networks (ANN) important physicochemical characteristics of molasses vinegar: pH, density, total acidity, ethanol, total aldehydes and furfural, obtained by flash evaporation operations and flash distillation clarification. Alcoholic and acetic fermented molasses were fed to a flash evaporator at four temperatures (61, 66, 71 and 76 ° C) and in three times (25, 35 and 45 min). The prediction was made with two networks: ANN and ANN-A-B, both with good performance. The ANN-A was of the feedforward (FF) type with Backpropagation (BP) training algorithms and set of Levenberg-Marquardt (LM) weights adjustment, topology: 6 inputs (operations data of flash evaporation-distillation), 7 linear outputs (physicochemical characteristics), 9 tangent sigmoidal neurons in 1 hidden layer, 0.5 moment coefficient, 0.01 learning rate, 0.0001 error goal and 20 training stages. The ANN-A showed better performance than a statistical model of first order. The ANN-B also FF, BP and LM algorithms, topology: 2 inputs (data from flash evaporation), 7 linear outputs (physical and chemical characteristics), 84 logarithm sigmoid neurons in 1 hidden layer, 0.5 moment coefficient, 0.01 learning rate, 0.0001 error goal and 300 training stages. The ANN-B showed the same predictive capacity as a statistical model of the first-order with interaction of terms.

Chemical Characterization of Orange Juice from Trees Infected with Citrus Greening (Huanglongbing)

The effects due to Candidatus Liberibacter infection, commonly called citrus greening or Huanglongbing (HLB), on volatile and nonvolatile components of orange juices, OJ, were examined using GC-MS and high-performance liquid chromatography (HPLC). HLB symptomatic, asymptomatic, and control "Hamlin" and "Valencia" oranges were harvested from December to May during the 2007 to 2008 harvest season. Brix/acid levels in control and asymptomatic juices were similar but symptomatic juices were as much as 62% lower than control juices. No bitter flavanone neohesperidosides were detected and polymethoxyflavone concentrations were well below bitter taste thresholds. Limonin concentrations were significantly higher (91% to 425%) in symptomatic juice compared to control but still below juice bitterness taste thresholds. Juice terpenes, such as gamma-terpinene and alpha-terpinolene, were as much as 1320% and 62% higher in symptomatic juice than control. Average ethyl butanoate concentrations were 45% lower and average linalool was 356% higher in symptomatic Valencia OJ compared to control. Symptomatic Valencia OJ had on average only 40% the total esters, 48% the total aldehydes, and 33% as much total sesquiterpenes as control juice. Total volatiles between control and symptomatic juices were similar due to elevated levels of alcohols and terpenes in symptomatic juice. There were no consistent differences between asymptomatic and control juices. The chemical composition of juice from HLB/greening symptomatic fruit appears to mimic that of juice from less mature fruit. The reported off-flavor associated with symptomatic juices probably stem from lower concentrations of sugars, higher concentrations of acid as all known citrus bitter compounds were either below taste thresholds or absent.

Changes on Enological Parameters of White Wine Packaged in Bag‐in‐Box during Secondary Shelf Life

This study investigated the effects of temperature (22, 35, and 45 degrees C), storage time (48, 30, and 15 d), and packaging type on the quality of white wine in bag-in-box (BIB) during the secondary shelf life. Several enological parameters (color and contents of free and total SO2, total aldehyde, and total phenol) were monitored and correlated with oxygen transmission rate (OTR) and Fourier transform infrared (FTIR) spectral data. Time and temperature had significant effects on color development and SO2 depletion during storage. The increased absorbance at 420 nm was correlated with decreases of free SO2 and total SO2. Overall, total phenol content correlated negatively with total aldehyde content. The variance of the enological parameters can be correlated with the OTR data, indicating the barrier properties for the tested packages were different. FTIR-ATR spectra of the wine were analyzed chemometrically using PLS algorithm. The resulting models were able to predict the A(420), free SO2, total SO2, total phenol, total aldehyde, and storage time of the wines. This technique can potentially be used as an efficient tool to evaluate the quality of wine.