Concentrations Of Total Volatile Compounds Research Articles

Preparation of 1-Amino-1-deoxyfructose Derivatives by Stepwise Increase of Temperature in Aqueous Medium and Their Flavor Formation Compared with Maillard Reaction Products

A novel method of Maillard reaction performed under stepwise increase of temperature was proposed for the preparation of Maillard reaction intermediate (MRI) derived from fructose (Fru) and phenylalanine (Phe). The optimal formation conditions of MRI in aqueous medium were determined as follows: pH 7.4 and heating for 100 min at 100 °C. The purified MRI was characterized to be 1-amino-1-deoxyfructose derivative (C15H21NO7, 327 Da) by mass spectrometry and NMR. The methodological effectiveness of this new developed method was further verified. Although almost similar types of volatile compounds were identified in the three heated solutions of Fru-Phe mixture, Maillard reaction products (MRPs) and 1-amino-1-deoxyfructose derivatives, the concentration of total volatile compounds was 118.30 μg/L relative to the internal standard for Fru-Phe mixture and increased by 64.49 and 1024.64 μg/L for MRPs and 1-amino-1-deoxyfructose derivative, respectively. The results showed that more fresh flavors were controlled formed from 1-amino-1-deoxyfructose derivative compared with those from MRPs or Fru-Phe mixture during the subsequent heating treatment; thus, the 1-amino-1-deoxyfructose derivatives could be a great potential substitute of unstable MRPs or Fru-Phe mixture in preparation of flavoring.

Volatile profile of elderberry juice: Effect of lactic acid fermentation using L. plantarum, L. rhamnosus and L. casei strains

In this study we explored, for the first time, the lactic acid fermentation of elderberry juice (EJ). A total of 15 strains isolated from dairy and plant matrices, belonging to L. plantarum, L. rhamnosus and L. casei, were used for fermentations. The volatile profile of started and unstarted EJ was characterized by HS-SPME/GC-MS technique after 48h of fermentation and 12days of storage at 4°C. All L. plantarum and L. rhamnosus strains exhibited a good capacity of growth while not all L. casei strains showed the same ability. The aromatic profile of fermented juices was characterized by the presence of 82 volatile compounds pertaining to different classes: alcohols, terpenes and norisoprenoids, organic acids, ketones and esters. Elderberry juice fermented with L. plantarum strains showed an increase of total volatile compounds after 48h while the juices fermented with L. rhamnosus and L. casei exhibited a larger increase after the storage. The highest concentration of total volatile compounds were observed in EJ fermented with L. plantarum 285 isolated from dairy product. Ketones increased in all fermented juices both after fermentation and storage and the most concentrated were acetoin and diacetyl. The organic acids were also affected by lactic acid fermentation and the most abundant acids detected in fermented juices were acetic acid and isovaleric acid. Hexanol, 3-hexen-1-ol (Z) and 2-hexen-1-ol (E) were positively influenced during dairy lactic acid bacteria strains fermentation. The most represented esters were ethyl acetate, methyl isovalerate, isoamyl isovalerate and methyl salicylate, all correlated with fruit notes. Among terpenes and norisoprenoids, β-damascenone resulted the main representative with its typical note of elderberry. Furthermore, coupling obtained data with multivariate statistical analyses, as Principal Component Analysis (PCA) and Classification Trees (CT), it was possible to relate the characteristic volatile profile of samples with the different species and strains applied in this study.

Indoor Air Quality of Residential Building Before and After Renovation

Abstract This study investigates the impact of energy renovation on the indoor air quality of an apartment building during the heating season. The study was performed in one residential building before and after its renovation. An evaluation of the indoor air quality was performed using objective measurements and a subjective survey. The concentration of CO2 was measured in the bedrooms, and a sampling of the total volatile compounds (TVOC) was performed in the living rooms of the selected apartments. Higher concentrations of CO2 and TVOC were observed in the residential building after its renovation. The concentrations of CO2, and TVOC in some of the cases exceeded the recommended maximum limits, especially after implementing energy-saving measures on the building. The average air exchange rate was visibly higher before the renovation of the building. The current study indicates that large-scale renovations may reduce the quality of an indoor environment in many apartments, especially in the winter season.

Flavor improvement of fermented soy sauce by extrusion as soybean meal pretreatment

Flavor, an important index of soy sauce quality, includes odor and taste which mainly depend on volatile compounds and amino acids. Soy sauce made from extruded mixture of soy meal and flour (EMSF) was employed in fermentation to improve the flavor of final product. Combination of Headspace solid phase microextraction (HS-SPME) and GC-MS was employed to identify the volatile compounds, 40 volatile compounds were identified in soy sauce made from EMSF and 24 volatile compounds in soy sauce made form cooked mixture of soy meal and flour (CMSF). Pyrazines and their derivatives occupied one-third of the total content of volatile compounds. Both samples had the same amino acid number, while total content of amino acids and contents of 15 kinds of amino acids in soy sauce made from EMSF were significantly higher than CMSF. Practical applications Extrusion had the advantage in low cost and capability of continuous processing, extruded mixture of soy meal and flour were used in soy sauce fermentation. Content of amino acids was improved by extrusion, this pretreatment method also increased volatile compounds of soy sauce and produced more desirable flavor and taste soy sauce.

Chemical Composition and Antioxidant Properties of Five White Onion (Allium cepaL.) Landraces

Five onion landraces belonging toBianca di Pompeicv., cultivated in Campania region (Italy), were characterized for their main quality parameters. The onion landraces were harvested at the end of the growth cycle corresponding to the ripening time and harvest month, respectively: February, March, April, May, and June. The total content of volatile compounds as well as the sulfur-containing compounds inAprilaticawas significantly (p≤0.05) higher than the other landraces investigated. The nutraceutical feature investigated through the total phenols, phenols profile, and antioxidant activity showed higher values for the samples harvested in spring months. High pungency values ranging from 9 to 14 μmol/g FW were found in all onion landraces investigated as enzymatically (alliinase) produced pyruvate (EPY). The organic acids profile (malic, citric, succinic, pyruvic, oxalic, ascorbic, and tartaric acids) highlighted malic and citric acids in higher amounts in all landraces. Fructose, glucose, and sucrose were found as soluble sugars and fructose was the most abundant. Generally, the results highlighted the growth temperature influence on the investigated quality parameters.

Difference in volatile profile between pericarp tissue and locular gel in tomato fruit

Aroma, a complex mixture of volatile compounds, plays an important role in the perception and acceptability of tomato products by consumers. Numerous studies have reported volatile profiles in tomatoes based on measurement of the whole fruit or pericarp tissue, however, little is understood regarding the volatile compositions in the inner tissues. The objective of this study was to investigate the differences in volatile profile between pericarp tissue and locular gel in tomato fruit. Based on HS-SPME-GC-MS analysis, totally 42 volatile compounds were detected in FL 47 and Tasti-Lee tomato fruits. Regardless of cultivars, a substantial higher concentration of total volatile compounds was observed in pericarp than that in locular gel, associated with higher levels of aldehydes, hydrocarbons, and nitrogen compounds. Pericarp tissue possessed higher levels of cis-3-hexenal, hexanal, heptanal, octanal, nonanal, cymene, terpinolene, undecane, dodecane, 2-phenylethanol, 6-methyl-5-hepten-2-one, 2-methylbutyl acetate, 1-nitro-pentane, and 1-nitro-2-phenylethane, while the abundances of 2-methylpropanal, butanal, 2-methylbutanal, 2-methyl-2-butenal, 2-methylpropanol, 3-methylbutanol, 2-methylbutanol, and 2-butanone were higher in locular gel. Principal component analysis (PCA) and cluster analysis using GC-MS and electronic nose (E-nose) data discriminated the two tissues.

Fatty Acid Profiles and Volatile Compounds Formation During Processing and Ripening of a Traditional Salted Dry Fish Product

The present research aimed to investigate the chemical changes and volatiles formation during processing and ripening of a traditional dry salted fish product prepared from landlocked shad (Alosa fallax lacustris). Proximate and fatty acid composition, thiobarbituric acid reactive substances (TBARS) values, color measurements and volatile compounds were determined in fresh fish and salted samples at 9, 40, 70 and 100 days of maturation. The fatty acid composition changed during ripening, with significant increase of saturated fatty acids and decrease of monounsaturated fatty acids. The total concentration of volatile compounds increased rapidly from fresh fish to dried product, with a maximum peak in correspondence to the drying step. The TBARS values increased from 0.76 μg/g in fresh fish to 10.95 μg/g in dry fish. Lipolytic and proteolytic reactions occurring in salted product, exacerbated by the presence of high amount of salt and ambient ripening temperature, contributed to the development of typical flavors. Practical Applications In Europe there is a growing interest in traditional fish products derived from local species and prepared with ancient recipes. Shad is one of the major species harvested in subalpine lakes and most of captured fish are traditionally subjected to an artisanal processing procedure, to give a dried fish product that is commercialized with the historic name of missoltino. This study describes the quality changes of prepared shad during processing and ripening. The appropriate combination of salt, drying and ripening conditions allows to obtain a product with optimal chemical and sensory properties. This study aims to provide the fish producers with improved criterions to traditional practices, in order to standardize the process and to obtain higher quality product for consumers. Moreover, these results represent a basis for product valorization and could contribute to a better consideration of the product on the market.

Effect of Roasting on Physicochemical Properties of Wild Almonds (Amygdalus scoparia)

AbstractRoasting enhances sensory quality of wild almonds (Amygdalus scoparia). The aim of the study was to evaluate the use of microwaves (480 W for 3 or 4 min) in roasting of wild almonds in comparison with traditional Spanish (165 °C for 20 min) and Iranian (soaking in 20 % NaCl in water for 30 min, drying at 60 °C for 2 h and roasting at 135 °C for 20 min) hot‐air processes. The influence of roasting wild almonds on moisture and oil contents, crispness, fatty acid profile, volatile compounds, and odour intensity was investigated. Roasting causes changes in appearance, texture and flavour, due to dehydration, browning, lipid oxidation, and diverse structural changes. The moisture content and hardness of the samples significantly decreased with all roasting methods. Roasting resulted in higher amounts of characteristics aroma compounds and only microwave roasting increased the oil content. The final recommendation is that microwave roasting at 480 W for 4 min led to roasted almonds of high physicochemical [dark and intense colour (L*44.9, a*8.4, and b*19.6), the highest content of total volatile compounds (132 mg kg−1), 85.2 % of unsaturated fatty acids], and sensory (high intensity of “roasted almond” aroma) quality. Microwaves can be used for roasting wild almond as a quick, safe, and economical method.

Effect of starter cultures on the quality of Suan yu, a Chinese traditional fermented freshwater fish

SummaryThe generation of volatile compounds of four starter cultures composed of isolated microorganisms from traditional Suan yu was investigated. The cultures included two pure starters (PS1: Lactobacillus plantarum 120 and PS2: Pediococcus pentosaceus 220) and two mixed starters (MS1: L. plantarum 120, Staphylococcus xylosus 135 and Saccharomyces cerevisiae 31 at 1:1:1; MS2: P. pentosaceus 220, S. xylosus 135 and S. cerevisiae 31 at 1:1:1). Naturally fermented Suan yu was used as control. The volatile compounds were collected from the headspace of the samples by Solid‐phase microextraction and analysed by gas chromatography–mass spectrometry. The type and total content of volatile compounds in the mixed‐starter‐fermented fish were higher than those of the pure‐starter‐fermented samples and control. A total of seventy nine and eighty volatile compounds were detected in Suan yu fermented with MS1 and MS2, respectively, with ethanol as the predominant compound and hexanal, ethyl acetate, 3‐methylbutanol, 3‐hydroxy‐2‐butanone, hexanoic acid ethyl ester and 2,3‐butanedione as the other compounds. Furthermore, the sensorial acceptance of the different products with mixed starter cultures seemed to improve the quality of Suan yu products.

Effect of different drying methods on the myosin structure, amino acid composition, protein digestibility and volatile profile of squid fillets

The impacts of freeze drying (FD), hot-air drying (AD), and heat pump drying (HPD) on myosin structure, amino acid composition, protein digestibility and volatile compounds of squid (Todarodes pacificus) fillets were evaluated. Freeze-dried squids showed similar amino acid composition to that of raw squids, but differed from that of AD and HPD samples. The percentage of in vitro digestibility followed the order of FD (76.81%)>HPD (70.51%)>raw (67.99%)>AD (61.47%) samples. AD caused more damage to squid myosin structure than HPD, while FD effectively retained the myosin integrity. Drying decreased total number of volatile compounds, but increased the content of total volatile compounds based on GC×GC–TOFMS results. HPD and AD samples had the highest and lowest total numbers and contents of volatiles, respectively. In general, FD provided squids with the best quality, followed by HPD. Considering the production cost and product quality, HPD demonstrated the potential for industrial application.

TVOCs emissions from disinfectants, bonding agents and acrylic substances in a controlled dental office

The aim of this study, which took place in a dental environment located at the centre of Athens, Greece, is to quantify the amount of Total Volatile Compounds (TVOCs), which were emitted from commonly used dental substances in a controlled dental micro-environment (8 surface disinfectants including both sprays and tissues, 8 bonding agents and 4 acrylic substances). TVOCs concentrations were monitored at three distances from the source (right above the source, 50cm and 100 cm distance from the source) for a period of minutes using a ppbRAE monitor. The environmental factors were complementary assessed using a prototype experimental setup consisted of a sonic anemometer and a hygrometer right above the source. Ventilation rates were estimated via CO2 concentrations. High TVOCs concentrations were found to be emitted from three out of the four acrylic substances, with average values as high as 42.000 ppb. Concentrations were substantially reduced away from the source (average values below 500 ppb for all substances). For disinfectants, above the source the concentrations ranged between 30.430 ppb and 10 ppb with an average value of 5.393 ppb. Significant differences were observed between TVOCs emitted from sprays which in general, were substantially higher than TVOCs emitted from wipes (average TVOCs conc. from sprays 8.327 ppb, while the respective value for tissues is 496 ppb). An effort was made to assess the dependence of the measured TVOCs concentrations on environmental factors such as wind speed and ventilation rates. It was found that the influence of environmental factors is not traceable, indicating the importance of emission patterns.

Effect of fat level on physicochemical, volatile compounds and sensory characteristics of dry-ripened “chorizo” from Celta pig breed

A traditional Spanish dry-ripened sausage “chorizo” from Celta pig breed was formulated with 10, 20 and 30% of back fat (LF, MF and HF, respectively). An increase in fat content significantly affected the chemical composition of the sausages at the end of ripening (higher fat content and lower protein content and moisture) and physico-chemical parameters (lower pH, aw, hardness, springiness and chewiness and higher TBARS index, L*, a* and b* values). With the increase of fat in the sausage formulation a higher total content of free fatty acids (FFA) was also obtained, showing a greater lipolysis than in LF sausages. All these parameters were significantly affected by ripening time. A lower total content of volatile compounds were found in HF sausages, being detected 3 alcohols, 4 aldehydes, 12 esters, 3 ketones, 7 aliphatic and 4 aromatic hydrocarbons. Sensorial analysis showed differences for fat level and fat-lean cohesiveness within appearance attributes; odour intensity and spices odour within odour attributes and hardness within texture attributes.

Volatile compounds of some popular Mediterranean seafood species

The volatile compounds of highly commercialised fresh Mediterranean seafood species, including seven fish (sand-smelt Atherina boyeri, picarel Spicara smaris, hake Merluccius merluccius, pilchard Sardina pilchardus, bogue Boobps boops, anchovy Engraulis encrasicolus and striped-mullet Mullus barbatus), squid (Loligo vulgaris), shrimp (Parapenaeus longirostris) and mussel (Mytilus galloprovincialis), were evaluated by simultaneous steam distillation-extraction and subsequent GC-MS analysis. A total of 298 volatile compounds were detected. The mussels contained the highest total concentration of volatile compounds, while pilchard among fish species contained the highest number and concentrations of volatile compounds. Individual patterns of volatile compounds have been distinguished. The fish species when compared to the shellfish species studied, contained 6 to 30 times more 1-penten-3-ol, higher quantities of 2-ethylfuran, and 2,3-pentanedione, which was absent from the shellfish species. Pilchard is characterized by a high concentration of alcohols, shrimps by the high presence of amines and S-compounds, while mussels by high amounts of aldehydes, furans, and N-containing compounds (pyridine, pyrazines and pyrrols). The fatty acid-originating carbonyl compounds in fish seem to be related to the species’ fat content.

Analysis of volatile compounds in Chinese soy sauces moromi cultured by different fermentation processes

The volatile compounds in Chinese soy sauce moromi cultured by different fermentation processes [lowsalt solid-state fermentation (LSSF), high-salt dilute-state fermentation (HSDF), and high-salt constant temperature fermentation (HSCT)] were determined by GC-MS. The LSSF moromi had the highest total concentration of volatile compounds, followed by HSCT and HSDF moromi. Volatiles such as ethyl linoleate and ethyl oleate dominated in HSCT moromi. 2,3-Butanediol and 2,6-dimethylpyrazine were present at high content in LSSF moromi. The hierarchal cluster analysis (HCA) and principal component analysis (PCA) were employed to investigate the fermentation process effect on the category of samples. Based on HCA, HSCT (a1 and a2) and HSDF (b1 and b2) clustered in 1 group, and LSSF (c1 and c2) located in another group. PCA illustrated that each kind of samples correlating with specific volatile compound groups were clearly differentiated according to their fermentation processes. The results suggest that GC-MS together with multivariate analyses could provide practical reference to recognize different Chinese soy sauces moromi.

Volatile compounds of some popular Mediterranean seafood species

The volatile compounds of highly commercialised fresh Mediterranean seafood species, including seven fish (sand-smelt Atherina boyeri, picarel Spicara smaris, hake Merluccius merluccius, pilchard Sardina pilchardus, bogue Boobps boops, anchovy Engraulis encrasicolus and striped-mullet Mullus barbatus), squid (Loligo vulgaris), shrimp (Parapenaeus longirostris) and mussel (Mytilus galloprovincialis), were evaluated by simultaneous steam distillation-extraction and subsequent GC-MS analysis. A total of 298 volatile compounds were detected. The mussels contained the highest total concentration of volatile compounds, while pilchard among fish species contained the highest number and concentrations of volatile compounds. Individual patterns of volatile compounds have been distinguished. The fish species when compared to the shellfish species studied, contained 6 to 30 times more 1-penten-3-ol, higher quantities of 2-ethylfuran, and 2,3-pentanedione, which was absent from the shellfish species. Pilchard is characterized by a high concentration of alcohols, shrimps by the high presence of amines and S-compounds, while mussels by high amounts of aldehydes, furans, and N-containing compounds (pyridine, pyrazines and pyrrols). The fatty acid-originating carbonyl compounds in fish seem to be related to the species’ fat content.

Influence of cultivation parameters on the composition of volatile compounds and physico‐chemical characteristics of kiwi fruit

The effect of four cultivation parameters (post-maturity harvest date, storage period at 0 °C and input of nitrogen or potassium fertilisers) on the physico-chemical characteristics and composition of volatile compounds in kiwi fruit (Actinidia deliciosa) were evaluated. Five physico-chemical parameters were selected, namely, pH, total acidity, dry matter, conductivity and refractive index. To our knowledge, no published data are available concerning the influence of nitrogen or potassium fertilisers on the volatile compounds and physico-chemical parameters in kiwi fruit. Except for total acidity, these parameters were only weakly influenced by cultivation parameters. The concentrations of five main volatile compounds [hexanal, (E)-hex-2-enal, hexan-2-ol, ethyl butyrate and hexanol] were also measured using gas chromatography and gas chromatography-mass spectrometry. This work showed that the total content of volatile compounds decreased with post-maturity harvest date and storage period of 3 months. In contrast, the input levels of nitrogen and potassium had little effect on the concentrations of volatile components This study demonstrates a high degree of difference in the physiochemical parameters and volatile composition of kiwi fruit, depending on the harvest date, the time of storage and the input of fertilisers.

Component analysis and sensory evaluation of Korean black raspberry (Rubus coreanus Mique) wines

SummaryThree types of Korean black raspberry wines were made from juice, juice‐pulp and juice‐pulp‐seed. Changes in the physicochemical properties and key compounds of the wines during fermentation were determined. The colour intensity was weakened with a 50% decrease in the anthocyanin content, but the colour intensity was strengthened by supplementation with pulp and seeds. Citric acid was the major organic acid (approximately 90%) of the wines, and the amino acid content was lowered to less than 10% by fermentation. The total volatile compound content was increased 5.3 times and nine new compounds were identified. The major components of the wines were isobutanol, n‐propanol and isoamyl acetate. The juice‐pulp‐seed wine contained the highest contents of anthocyanin, polyphenols and proanthocyanin. The anti‐oxidative activity of wines increased with an increasing content of polyphenols. The content of proanthocyanidin, a compound for pucker and bitter tastes, was approximately two to three times greater than in commercial grape wines. In a sensory test, the highest scores for colour, flavour, taste and overall acceptance were awarded to the juice‐pulp‐seed 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.

Chemical, functional and quality properties of Japanese plum ( Prunus salicina Lindl.) as affected by mulching

The aim of this study was to contribute to the chemical, functional and qualitative characterisation of Japanese plum ( Prunus salicina L., cv. Red Beaut, genotype “606”) cultivated with and without a mulching plastic by investigating the organic acids and sugars profiles, the total antioxidant activity and total polyphenols content, the volatile composition and the sensory profile. Results indicated that total sugars, organic acids contents and the total concentration of volatile compounds were slightly higher in plums from trees with the mulching plastic film being used as a cultural practice, although differences were not statistically significant. Sixteen compounds were isolated from the volatile fraction from six different chemical families: aldehydes, monoterpenes, monoterpenoids, phenylpropanoids, acids and ketones. The major compounds in the volatile profile of plum juices were trans-linalool oxide, terpinolene, nonanal and α-terpineol. However, total antioxidant activity, total polyphenols content and the sweetness intensity were decreased by the use of the mulching plastic. Therefore, mulching with plastic materials with high light reflectance (e.g. white) seemed to be required to improve the quality of plums.

EVALUATION OF VIRGIN OLIVE OIL MINOR COMPOUNDS IN PROGENIES OF CONTROLLED CROSSES

ABSTRACT An experimental investigation was carried out to evaluate the quality of virgin olive oils obtained by intervarietal cross-breeding program. Twelve extra virgin olive oil cultivars were characterized by their chemical composition. The experimental data showed that new releases were characterized by an appreciable α-tocopherol (ranging from 60.09 to 153.97 mg/kg) and by a high content of total volatile compounds especially of the trans-2-hexenal. Simple phenols such as hydroxytyrosol, tyrosol, vanillic acid, p-coumaric acid, ferulic acid and vanillin were identified and quantified by high-performance liquid chromatography in most of the oils. The flavonoids compounds (apigenin and luteolin) were also found. The results indicated that a considerable oil composition variability can be achieved genetically, by breeding. PRACTICAL APPLICATIONS The olive oil characterization of the new releases is an important way to study the effect of the breeding method on their chemical composition in an attempt to select new ones with superior genotypes.