Concentrations Of Total Volatile Compounds Research Articles

Effects of pretreatment methods and leaching methods on jujube wine quality detected by electronic senses and HS-SPME-GC-MS.

Conventional analysis, electronic senses and HS-SPME-GC-MS were applied to evaluate the effects of pretreatment methods and leaching methods on jujube wine quality. Significant differences (p<0.05) in the levels of alcohol content, color, taste and aroma were observed among all the jujube wine samples, in which the pulp and pectase fermented jujube wine was the best among all. Moreover, rather than taste, aroma is the most significantly (p<0.05) affected. In regard to aroma, a total of 182 volatile compounds were identified by HS-SPME-GC-MS. It was found that the blended-into-pulp treatment and the leached-by-pectase treatment had notable positive effects on jujube wine. The pulp and pectase fermented jujube wines exhibited the highest concentration of total volatile compounds as well as alcohols, esters, acids and aldehydes. Thus, the optimal pretreatment method and leaching method for jujube wine fermentation are blended-into-pulp and leached-by-pectase respectively.

Effect of pre- and post-rigor on texture, flavor, heterocyclic aromatic amines and sensory evaluation of roasted lamb

This study investigated the variation in texture, flavor, heterocyclic aromatic amines (HAAs) and sensory evaluation of pre- and post-rigor roasted lamb. Topside muscles were collected from twenty-eight lamb carcasses at 1 h, 6 h, 12 h, 1 d, 3 d, 5 d and 7 d postmortem and then roasted at 180 °C for 8 min. According to the pH and shear force (SF) values, the lamb muscles at 1–12 h, 1 d and 3–7 days postmortem were considered to be in the phases of pre-rigor, rigor and post-rigor, respectively. Pre-rigor roasted lamb showed a lower roasting loss, while the post-rigor roasted lamb showed a lower SF value. Higher concentrations of total volatile compounds were found at 3 days postmortem. The total contents of HAAs were significantly lower in pre-rigor roasted lamb compared to the post-rigor roasted lamb (P < .05). Overall, it was concluded that both pre- and post-rigor “roasted lamb” have their own special properties.

Improved flavor profiles of red pitaya (Hylocereus lemairei) wine by controlling the inoculations of Saccharomyces bayanus and Metschnikowia agaves and the fermentation temperature.

The effects of the inoculation method of Saccharomyces bayanus BV818 and non-Saccharomyces yeast Metschnikowia agaves P3-3 and the fermentation temperature on the volatile profiles of red pitaya wine were investigated in the present study. Although the growth of P3-3 was inhibited by BV818 in the mixed inoculations, simultaneous and sequential inoculations promoted the production of seven volatiles, including higher alcohols (propan-1-ol, 3-methyl-1-butanol and phenethyl alcohol), esters (ethyl decanoate and diethyl succinate), acid (2-ethylhexanoic acid), and ketone (acetoin). Sequential inoculation produced the largest total content of volatile compounds and exhibited the best in the global aroma. The red pitaya wine produced in different inoculations can be separated by its main volatile components. Furthermore, the highest total content was yielded at 25°C for alcohols and at 21°C for esters and acids. Within an experimental range of 17°C to 29°C, the contents of benzaldehyde and acetoin decreased with the increase in temperature, whereas the change in 4-ethyl-2-methoxyphenol content was the opposite. The similarly high total contents of volatiles and global aroma score were yielded via sequential inoculation at 21°C and 25°C. Therefore, the desired red pitaya wine can be effectively produced by modulating the inoculation method and fermentation temperature.

Characterization and potential use of Diplotaxis erucoides as food ingredient for a sustainable modern cuisine and comparison with commercial mustards and wasabis

Diplotaxis erucoides is a wild edible plant (WEP) of the Brassicaceae family, growing as a weed in Mediterranean countries. It contains glucosinolates, which are hydrolyzed by myrosinase rendering isothiocyanates; these compounds are responsible for its characteristic aroma and flavor, similar to that of mustard or wasabi. The aim of this study was to characterize the Diplotaxis erucoides plant by analyzing its volatile, sugar, organic acid, and sensory profiles. This information will be essential to decide whether it is possible to develop sustainable and healthy alternatives to commercial mustard and wasabi using this WEP. Two Diplotaxis-based products were prepared one cream and one mayonnaise. Allyl isothiocyanate represented more than 80% of total content of volatile compounds in the leaves, pods and stems. The sugar and organic acid content of Diplotaxis and its based products were very low. The Diplotaxis products were characterized by having intense Diplotaxis odor/aroma, herbaceous flavor and long aftertaste, but lacked some pungency. Diplotaxis erucoides is a sustainable and healthy option to produce herbaceous and pungent sauces.

“Arbequina” Olive Oil Composition Is Affected by the Application of Regulated Deficit Irrigation during Pit Hardening Stage

AbstractThree new regulated deficit irrigation (RDI) treatments were applied to “Arbequina” olive orchards during pit hardening. Oil quality was determined by measuring analytical parameters for olive oil grading, antioxidant activity, total phenol content, fatty acid profile, volatile compounds profile, and sensory analysis. Oils from RDI were classified as “extra virgin olive oil” and their quality was improved due to their higher antioxidant potential (ABTS+ [increased ~75%] and DPPH˙ [increased ~25%] assays) and phenols (increased ~53%) than control. Concentration of total volatile compounds decreased (~27%) but RDI olive oils showed a more balanced profile (alcohols, aldehydes, and esters). Monounsaturated fatty acid content increased (~5%) and atherogenic and thrombogenic indexes decreased (~8.5%) in RDI olive oil. Regarding sensory analysis, RDI provided more balanced oils with higher fruit aroma than control. Other benefits of RDI olive oil, when compared with oil from full irrigated orchards are reduced use of water and improved functional and sensory quality.

Insights into the chemosensory basis of flavor in table grapes.

The full flavor of grape berries is determined by the interaction of sugars, acids, volatile compounds, and other berry properties, such as astringency. Sugars and acids are important for berry taste, whereas volatile compounds are important for the unique berry flavors, e.g., monoterpenes for the Muscat varieties. We explored the basis for 'fruity' flavor perception in table grapes. Samples were collected from 134 new table grape lines and commercial varieties and tested chemically for their volatile profiles and organoleptically by tasting panels. At the sensory level, flavor impression was strongly correlated with berry preference, whereas among 'fruity', 'neutral', 'herbaceous,' and 'Muscat', only the 'fruity' flavor was correlated with berry preference. At the chemical level, 114 volatile compounds were detected in the 81 breeding lines and cultivars examined, and grouped into 'core' and 'unique' categories. The typical berry flavor seemed to depend on the major volatile aldehydes-1-hexanal and (E)-2-hexenal-accounting for up to an average 85% of the berry's core volatile concentration. We found four volatile compounds-α-bergamotene, geranyl formate, aristolene and α-penansinene-previously undetected, to our knowledge, in fresh grape berries. High 'fruity' flavor scores were related to three independent factors: (i) presence of unique volatile compounds, such as the sesquiterpene α-copaene, (ii) higher total concentration of volatile compounds, (iii) optimal maturity associated to high total soluble solids (TSS) levels, interacting with berry volatile composition. These combined sensory and analytical data on the flavor of table grapes improve our understanding of the complex interface between chemical and sensory perception in fruit. © 2019 Society of Chemical Industry.

Characterization of the key aroma compounds in Longjing tea using stir bar sorptive extraction (SBSE) combined with gas chromatography-mass spectrometry (GC-MS), gas chromatography-olfactometry (GC-O), odor activity value (OAV), and aroma recombination.

Longjing tea is the most famous premium green tea, and is regarded as the national tea in China, with its attractive aroma contributing as a prime factor for its general acceptability; however, its key aroma compounds are essentially unknown. In the present study, volatile compounds from Longjing tea were extracted and examined using stir bar sorptive extraction (SBSE) combined with gas chromatography-mass spectrometry (GC-MS). Data obtained from the present study revealed that 151 volatile compounds from 16 different chemical classes were identified by GC-MS analysis. Enols (8096µg/kg), alkanes (6744µg/kg), aldehydes (6442µg/kg), and esters (6161µg/kg) were the four major chemical classes and accounted for 54% of the total content of volatile compounds. Geraniol (6736µg/kg) was the most abundant volatile compound in Longjing tea, followed by hexanal (1876µg/kg) and β-ionone (1837µg/kg). Moreover, 14 volatile compounds were distinguished as the key aroma compounds of Longjing tea based on gas chromatography-olfactometry (GC-O) analysis, odor activity value (OAV) calculations, and a preliminary aroma recombination experiment, including 2-methyl butyraldehyde, dimethyl sulfoxide, heptanal, benzaldehyde, 1-octen-3-ol, (E, E)-2,4-heptadienal, benzeneacetaldehyde, linalool oxide I, (E, E)-3,5-octadien-2-one, linalool, nonanal, methyl salicylate, geraniol, and β-ionone. This is the first comprehensive report describing the aroma characterizations and the key aroma compounds in Longjing tea using SBSE/GC-MS. The findings from this study contribute to the scientific elucidation of the chemical basis for the aromatic qualities of Longjing tea.

Relationship between CsLOX gene expression and C6 and C9 aldehydes during cucumber fruit storage

Abstract Changes in volatile compounds, the ratio of six-carbon (C6) to nine-carbon (C9) aldehydes, the ratio of linoleic acid to linolenic acid and CsLOX gene expression patterns were investigated in cucumber fruits of two different inbred lines after storage at 25 °C or 4 °C. The content of total volatile compounds in both lines was lower and the peak was later for the fruit stored at 4 °C than for that stored at 25 °C, whereas C6 was produced more rapidly than C9 at both temperatures and in both lines. The amount of linoleic acid cleaved at 4 °C was greater than that cleaved at 25 °C, and (E, Z)-2,6-nonadienal/(E)-2-nonenal content was higher at 25 °C than at 4 °C in both lines. There were different expression patterns for cucumber CsLOX genes at the two storage temperatures in the different lines. Principal component analysis showed that the 9-type CsLOX02 was closely related to the formation of C9 aldehydes and the 13-type CsLOX16, CsLOX17, CsLOX19, and CsLOX20 were closely related to formation of C6 aldehydes. Therefore, the expression of CsLOXs might be responsible for differences in the production of volatile compounds at the different storage temperatures.

Effect of Different Yeast Strains and Temperature of Fermentation on Basic Enological Parameters, Polyphenols and Volatile Compounds of Aurore White Wine.

The aim of this study was to investigate the content of phenolics by Ultra Performance Liquid Chromatography–Photodiode Array (UPLC–PDA), and volatile compounds by Gas Chromatography–Mass Spectroscopy (GC–MS), antioxidant capacity by 2,2′-azinobis-(3-ethylbenzothiazoline-6-sulfonic acid) radical cation (ABTS•+) and ferric-reducing antioxidant power (FRAP) assay, and color of Comission Internationale de l’Eclairage system (CIE) L*a*b* cv. Aurora white wine depending on fermentation conditions (a temperature of 12 °C vs. 20 °C and type of natural and commercial yeast (Saccharomyces cerevisiae vs. Saccharomyces bayanus)). The final wine differed in the content of total phenolic compounds (201.0–287.2 mg/L), except for the variants fermented at 20 °C with S. cerevisiae (321.9 and 329.4 mg/L for S. cerevisiae as Challenge Aroma White and SIHA® Cryaroma type, respectively). A decrease in antioxidant activity ranging from 43.3% to 65.4% (ABTS and FRAP assay) in the matured wine vs. must was demonstrated. S. cerevisiae wine was also characterized by the highest content of total volatile compounds (3.7–4.2 mg/L vs. 1.3 mg/L in the must). In general, the wine obtained with S. cerevisiae had higher alcohol content, antioxidant capacity, and was richer in polyphenolic and volatile compounds.

Volatome finger printing of red wines made from grapes grown under tropical conditions of India using thermal-desorption gas chromatography-mass spectrometry (TD-GC/MS).

The current study evaluated the key characters of aroma composition in diversified red wines (Cinsaut, Grenache, Cabernet Franc, Petit Verdot, Cabernet Sauvignon, Nielluccio, Tempranillo, Syrah, Merlot and Caladoc). Out of hundreds of volatile compounds 64 compounds were considered for study. Different groups consisting of fatty acids, volatile alcohols, aldehydes, esters, volatile phenols and terpenes were analysed using gas chromatography mass spectrometry coupled with thermal desorption (TD-GC-MS). Among all these diversified classes, alcohols were found as the most dominant group followed by esters and acids whereas aldehydes, phenols and terpenes were found to be minor compounds. Among the varieties, Nielluccio wine recorded highest concentration of total volatile compounds (191.53mg/L) while, it was least in Caladoc wines (15.45mg/L). The principal component analysis clearly differentiated Grenache wines based on their relationships between scores and their aroma composition followed by Nielluccio and Cinsuat wines. Out of sixty four compounds, only six aromatic compounds viz. butanediol, isoamyl actate, γ-Terpene, butanol, acetic acid and furfural have satisfying aroma descriptors with floral and fruity nuances and contribute to differentiate the Grenache wines from other varieties which have similar scores in PC1 analysis. The cluster analysis also suggested that the wines in the same group (Cinsaut, Tempranillo and Syrah), (Cabernet Franc, Cabernet Sauvignon, Caladoc and Merlot) and (Nielluccio and Petit Verdot) had similar aroma characterization. Grenache wines were well differentiated from the sub group formed by other red varieties.

Genome-Wide Analysis and Characterization of the Aux/IAA Family Genes Related to Floral Scent Formation in Hedychium coronarium.

Auxin plays a key role in different plant growth and development processes, including flower opening and development. The perception and signaling of auxin depend on the cooperative action of various components, among which auxin/indole-3-acetic acid (Aux/IAA) proteins play an imperative role. In a recent study, the entire Aux/IAA gene family was identified and comprehensively analyzed in Hedychium coronarium, a scented species used as an ornamental plant for cut flowers. Phylogenetic analysis showed that the Aux/IAA gene family in H. coronarium is slightly contracted compared to Arabidopsis, with low levels of non-canonical proteins. Sequence analysis of promoters showed numerous cis-regulatory elements related to various phytohormones. HcIAA genes showed distinct expression patterns in different tissues and flower developmental stages, and some HcIAA genes showed significant responses to auxin and ethylene, indicating that Aux/IAAs may play an important role in linking hormone signaling pathways. Based on the expression profiles, HcIAA2, HcIAA4, HcIAA6 and HcIAA12, were selected as candidate genes and HcIAA2 and HcIAA4 were screened for further characterization. Downregulation of HcIAA2 and HcIAA4 by virus-induced gene silencing in H. coronarium flowers modified the total volatile compound content, suggesting that HcIAA2 and HcIAA4 play important roles in H. coronarium floral scent formation. The results presented here will provide insights into the putative roles of HcIAA genes and will assist the elucidation of their precise roles during floral scent formation.

Effect of the herbs used in the formulation of a Spanish herb liqueur, Herbero de la Sierra de Mariola, on its chemical and functional compositions and antioxidant and antimicrobial activities

Herbero de la Sierra de Mariola is a traditional Spanish herb liqueur which can have up to 15 different plants. The aim of this study was to help in deciding which are the best suited herbs to be used to prepare a liqueur with the highest contents of bioactive compounds and their functional properties. Chemical parameters (FT-IR spectroscopy), total contents of bioactive compounds (polyphenols, flavonoids, and phenolic acids), sensory quality (total content of volatile compounds and aroma intensity), antioxidant activity (DPPH‧ and ABTS+), and antimicrobial activity, and sensory intensity were the parameters studied. In general, the best highest contents of the bioactive compounds and functional activities were found in liqueurs of the Lamiaceae family. An optimized version of this traditional liqueur might contain (i) winter savory, (ii) fennel, (iii) thyme, and (iv) peppermint. This study can be an example of how the scientific knowledge can be used to optimize traditional products, such as an Herbero de la Sierra de Mariola, and why not also to support the advantages of these products to establish future marketing campaigns.

Influence of high-pressure processing at different temperatures on free amino acid and volatile compound profiles of dry-cured ham

The effect of high pressure processing (HPP) (600 MPa during 6 min) at different temperatures (0, 20 and 35 °C) in dry-cured ham has been studied in order to optimize the technique and reduce its impact on chemical characteristics, which are widely related with sensorial parameters. Vacuum-packed slices from 120 dry-cured hams were used. These slices were submitted to four different treatments: without application of pressure or temperature (CO), high pressure treatment at 0 °C (HPP-0), high pressure treatment at 20 °C (HPP-20), and high-pressure treatment at 35 °C (HPP-35). The effect of the treatments on free amino acids and volatile compounds profile was evaluated. The HPP-35 treatment significantly (P < 0.001) increased the total free amino acid content (6415.63 mg/100g dry matter) when compared to the contents of the CO, HPP-0 and HPP-20 treatments (5313.16, 4787.30 and 5072.48 mg/100g dry matter, respectively). Significant differences were also found among treatments in the content of 13 individual free amino acids, and HPP-35 samples presented the highest values in 12 of them. Similarly, the total volatile compound content was influenced by temperature-assisted HPP treatments. The HPP-35 treated samples showed the highest content (78,415.27 AU × 103/g dry-cured ham) and the HPP-0 treated samples the lowest content (28,584.14 AU × 103/g dry-cured ham). No significant differences were observed between CO and HPP-20 treatments. The fractions of volatile compounds derived from lipolysis, proteolysis and microbial activity were significantly modified by the different treatments. HPP-0 samples presented lower values of alcohol and hydrocarbon contents, whereas HPP-35 samples showed higher ketone and ester contents.

AROMATIC PROFILE OF RED WINES FROM GRAPEVINE VARIETIES RUBIN, STORGOZIA, BOUQUET, TRAPEZITSA, KAYLASHKY RUBIN AND PINOT NOIR, CULTIVATED IN THE REGION OF CENTRAL NORTHERN BULGARIA

The objective of this study was to determine the aromatic profile of red wines obtained from Rubin, Storgozia, Bouquet, Trapezitsa, Kaylashky Rubin and Pinot Noir varieties from the region of Central Northern Bulgaria. First five varieties are hybrids selected in the Institute of Viticulture and Enology (IVE). Pinot Noir was used for control. GC-FID study for determination of the aromatic profile of red wines from proposed varieties was conducted. Twenty four volatile compounds were identified: 9 esters, 8 higher alcohols, 1 aldehyde, 5 terpene alcohols. The presence of methyl alcohol in all wines were found. Its concentrations were normal for red wines. The highest total content of volatile compounds was found in the wine from Kailashky Rubin variety (693.97 mg.dm-3). The ester fraction was dominated by ethyl acetate. The highest total ester content was found in the wine from Pinot Noir variety (204.08 mg.dm-3). It was followed by the wine from Bouquet variety (195.75 mg.dm-3). Acetaldehyde was the major established aldehyde. It was found in the largest quantity in the wine from Trapezitsa variety (87.44 mg.dm-3). 2-methyl-1-butanol (active amyl alcohol) and 3-methyl-1-butanol (isoamyl alcohol) were found in the highest content from the higher alcohols fraction. The highest total content of higher alcohols was found in the wine from Rubin variety (379.38 mg.dm-3). Five terpene alcohols were identified in the wines. Geraniol was presented in all examined wines. An extensive aromatic characterization by gas chromatographic analysis of red wines obtained from grapevine varieties selected in the Republic of Bulgaria was carried out. The research proves that the red wines obtained in the conditions of Central Northern Bulgaria were characterized by a complex aromatic composition due to the presence of different esters, higher alcohols and terpenes.

Determination of the volatile and polyphenol constituents and the antimicrobial, antioxidant, and tyrosinase inhibitory activities of the bioactive compounds from the by-product of Rosa rugosa Thunb. var. plena Regal tea

BackgroundThe phytochemical constituents and biological activities of Rosa rugosa Thunb. var. plena Regal flower cell sap (RFCS) were investigated.MethodsVolatile constituent, such as linalool, phenylethyl alcohol, citronellol, α-bisabolol, were identified by GC-MS. The contents of hyperoside, kaempferol-3-O-rutinosid, rutin, and luteolin as well as the total flavonoid content in RFCS were determined by HPLC and HPLC-MS. The total polyphenol content was evaluated by the Folin-Ciocalteu colorimetric method. The antioxidant activities of RFCS and the standards were evaluated by DPPH and ABTS radical scavenging assays. The tyrosinase inhibitory activities of the rose samples and standard substance were determined by a spectrophotometric method. The antimicrobial effects of RFCS were evaluated in terms of minimum inhibitory concentrations (MICs) and minimum bactericidal concentrations (MBCs) or minimum Fungicidal concentrations (MFCs).ResultsThe rose fraction exhibited a high content of biologically active ingredients. The total content of volatile compounds in RFCS was approximately 48.21 ± 2.76 ng/mL. The total phenolic acid content and total flavonoid content were 0.31 ± 0.01 mg/mL and 0.43 ± 0.01 mg/mL, respectively. Its IC50 value in the DPPH assay was 1120 ± 42 μg/mL, and its IC50 value for ABTS radical scavenging activity was 1430 ± 42 μg/mL.RFCS strongly inhibited L-tyrosine oxidation with an IC50 value of 570 ± 21 μg/mL. Every compound identified in RFCS exhibited broad-spectrum antimicrobial activity. F. nucleatum was most susceptible to RFCS with an MIC of 64 μg/mL and MBC of 250 μg/mL.ConclusionsDue to its rose-like aroma, phenylethyl alcohol may be combined with linalool for use as a natural skin-whitening agent and skin care additive in the and pharmaceutical industries.

Application of temperature and ultrasound as corrective measures to decrease the adhesiveness in dry-cured ham. Influence on free amino acid and volatile compound profile

The impact of low temperature treatment and its combination with ultrasound has been evaluated in order to correct texture defects in dry-cured hams. A total of 26 dry-cured hams, classified as high proteolysis index (PI>36%), were used. From these hams, ten slices from each ham sample were cut, vacuum packed and submitted to three different treatments: control (without treatment), conventional thermal treatments (CV) and thermal treatment assisted by power ultrasound (US). The impact of these treatments on instrumental adhesiveness, free amino acid and volatile compounds profile were assessed. Statistical analysis showed that both US and CV treatments, significantly (P < .001) decreased the instrumental adhesiveness of dry-cured hams from 85.27 g for CO to 40.59 and 38.68 g for US and CV groups, respectively.The total free amino acid content was significantly (P < .001) affected by both treatments, presenting higher values the samples from the US group (6691.5 vs. 6067.5 vs. 5278.2 mg/100 g dry matter for US, CV and CO groups, respectively). No significant differences were observed between US and CV treatments. All the individual free amino acids were influenced by ultrasound and temperature treatments, showing the highest content in sliced dry-cured ham submitted to ultrasounds at 50 °C, except for isoleucine which presented the highest level in samples from CV group. Similarly, significant differences (P < .05) were also detected in the total volatile compound content between CO and US groups, with a higher concentration in the CO batch (56,662.84 AU × 103/g of dry-cured ham) than in the US treatment (45,848.47 AU × 103/g of dry-cured ham), being the values in the CV treatment intermediate (48,497.25 AU × 103/g of dry-cured ham). Aldehydes, ethers and esters, carboxylic acids and sulphur compounds were more abundant in the CO group, while CV group showed higher concentrations of ketones, alcohols and nitrogen compounds.

Influence of Maceration and the Addition of Flavoring Enzyme on the Aromatic Profile of Red Wines from the Region of Central Northern Bulgaria

Gas chromatographic study (GC-FID) for determination of the influence of maceration and addition of flavoring enzyme on the aromatic profile of red wines from Central Northern Bulgaria was conducted. The wines were obtained from selected clones (Gamza 52-9-4, Gamza 52-9-5 and Pamid 5/76) and varieties (Kaylashky rubin, Trapezitsa). Nineteen volatile compounds have been identified. Of these, 5 higher alcohols, 9 esters and 4 terpene alcohols affected the aroma of the wines. Methyl alcohol has been found in wines. Its concentrations were normal for red wines. The highest total concentration of volatile compounds was found in the Gamza clone 52-9-5 control (363.10 mg/dm3). Gamza 52-9-4 clone, Kaylashky rubin and Trapezitsa varieties have been observed to increase the content of higher alcohols after addition of flavoring enzyme, while in the wines from Gamza 52-9-5 clone and Pamid 5/76 clone, the trend was reversed. The ester composition of the experimental samples was diverse. Increased ester content, after the addition of flavoring enzyme was found in Gamza 52-9-4 clone, Kaylashky rubin and Trapezitsa variety. In Gamza 52-9-5 and Pamid 5/76, the trend was reversed. The dominant ester was ethyl acetate. The highest content of terpene alcohols was observed in the wine from the control variant of clone Pamid 52-9-4 (0.69 mg/dm3).

Effect of proteolysis index level on instrumental adhesiveness, free amino acids content and volatile compounds profile of dry-cured ham

Defective textures in dry-cured ham are a common problem that causes important economic losses in the ham industry. An increase of proteolysis during the dry-cured ham processing may lead to high adhesiveness and consumer rejection of the product. Therefore, the influence of proteolysis index (PI) on instrumental adhesiveness, free amino acids and volatile profile of dry-cured ham was assessed. Two hundred Spanish dry-cured ham units were firstly classified according to their PI: low PI (<32%), medium PI (32–36%) and high PI (>36%). Instrumental adhesiveness was affected by PI, showing the lowest values in the batch with low PI. Significant differences (P < 0.05) among groups were found in six amino acids: serine, taurine, cysteine, methionine, isoleucine and leucine. The content of leucine, serine, methionine, and isoleucine significantly (P < 0.05) increased as the proteolysis index rose. However, taurine and cysteine content showed an opposite behaviour, reaching the highest values in the dry-cured hams with low PI.Significant differences (P < 0.001) in the total content of volatile compounds among ham groups were observed, with the highest concentration in the batch with low PI, and decreasing the concentration as the PI increased. Regarding the different chemical families of volatiles, the hydrocarbons (the main family), alcohols, aldehydes, ketones and acids were more abundant in the hams showing the lowest PI. Esters did not show significant differences among the three batches of hams studied. The present study demonstrated that, apart from the effect on the adhesiveness, an excessive proteolysis seems to be associated with negative effects on the taste and aroma of the dry-cured ham.

Effects of nutrient solution supply amount on yield, quality and volatile matter of tomato

We examined the effects of different amounts of nutrient solution supply on the yield, quality and volatile substances of tomato fruit by substrate cultivation. Using tomato cultivar 'HL2109' as experimental material, four treatments were set, including Control: irrigating with 117 L pure water for each plant; T1: irrigating each plant with 39.0 L of nutrient solution; T2: irrigating each plant with 58.5 L of nutrient solution; T3: irrigating each plant with 117 L of nutrient solution. The quality and volatile substances of tomato fruits were determined by using chemical method and SPME-GC-MS technique. The results showed that the yield per plant and the gross production increased and then decreased with the increases of nutrient solution supply. The yield of T2 was the highest among all treatments. The yields of T1, T2 and T3 were 29.3%, 72.6% and 47.0% higher than that in Control, respectively. The irrigation water use efficiency of T1 was the highest and T2 took second place, though the difference being not significant. The soluble solids content and sugar acid ratio of tomato fruits in T2 were the highest, and the flavor and quality were significantly improved. The content of ascorbic acid and soluble protein gradually increased with the increases of nutrient solution supply. The contents of total soluble sugar and reducing sugar were first increased and then decreased, both being highest in T2. Using GC-MS analysis, a total of 69 volatile compounds were detected. The total content of volatile compounds from T1, T2 and T3 were higher than that in Control, which presented as T2﹥T1﹥T3﹥CK. Among them, the content of volatile compounds from T2 was 6971 μg·kg-1, which was 1.97 times higher than that in the Control. The content from T3 was 4070 μg·kg-1, being 0.73 times of that in the Control. The contents of 1-Pentene-3-one, 6-Methyl-5-hepten-2-one, hexanal, hexanoic acid, Phenylacetaldehyde and cis-3-hexenal were highest in T2 among all treatments. Moreover, the content of characteristic volatile compounds, the quantity and total content of volatile compounds were highest in T2. Taken together, the T2 treatment (irrigating each plant with 58.5 L of nutrient solution) had the best effects, with the quality and content of volatile compounds in tomato fruit being improved.

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.