反应温度和时间对抗坏血酸/精氨酸Maillard反应体系中挥发性化合物形成的影响

采用顶空固相微萃取-气相色谱-质谱联用技术对抗坏血酸/精氨酸反应体系在不同反应温度和时间下的产物进行鉴定,共鉴定出包括吡嗪、醛、呋喃、醇和吲哚在内的24种化合物,其中14种吡嗪化合物为主要香味化合物。考察了反应温度和时间对产物特别是对吡嗪化合物的影响。结果表明,随着反应温度的升高和反应时间的延长,吡嗪类化合物的总量均增加;其中,随反应温度的升高,相对其他吡嗪化合物2-乙基-6-甲基吡嗪、3-乙基-2,5-二甲基吡嗪的量明显增加;随反应时间的延长,2-乙基-6-甲基吡嗪的量明显增加。     

Comparison of fermented soybean paste (Doenjang) prepared by different methods based on profiling of volatile compounds

Abstract: In this study, 2 different extraction methods, namely solvent‐assisted flavor evaporation (SAFE) and solid‐phase microextraction (SPME), were employed to investigate the comprehensive volatile profile of Doenjang (one of Korean fermented soybean pastes) efficiently. Quantitatively, major volatiles of Doenjang isolated by SAFE were 3‐methylbutanoic acid, butanoic acid, 3‐hydroxy‐2‐methyl‐4H‐pyran‐4‐one (maltol), ethyl 2‐methylbutanoate, 2‐methylpropanoic acid, tetramethylpyrazine, and 4‐ethyl‐2‐methoxyphenol, while ethanol, ethenylbenzene, ethyl benzoate, ethyl linoleate, ethyl acetate, ethyl butanoate, tetramethylpyrazine, and ethyl 2‐methylpropanoate extracted by SPME. In addition, volatile profiling that applied principal component analysis to gas chromatography‐mass spectrometry datasets allowed Doenjang samples that had been prepared using different traditional and commercial methods to be discriminated, and the volatile compounds that contributed to their discrimination were assigned. The major volatiles that were related to differentiation of traditional and commercial Doenjang samples were 2‐pentylfuran, 4‐ethylphenol, dihydro‐5‐methyl‐2(3H)‐furanone, butanoic acid, pyrazines (for example, 2‐ethyl‐5‐methylpyrazine and 2,3‐dimethylpyrazine), esters (for example, ethyl 4‐methylpentanoate and diethyl succinate), maltol, dimethyl disulfide, 2‐ and 3‐methylbutanal, hexanal, 4‐vinylphenol, and ethanol.     

固相微萃取虾味香精中风味化合物的研究

以虾下脚料酶解液、L-精氨酸、L-丙氨酸、还原糖、硫胺素盐酸盐等为原料制备热反应虾味香精;采用固相微萃取技术并结合GC-MS检测技术对产物进行分析,总共获得61种挥发性化合物,尤其是鉴定出了二甲基二硫醚、吡嗪、3-甲基噻唑、2,5-二甲基吡嗪、2,6-二甲基吡嗪、2,3-二甲基吡嗪、三甲基吡嗪、二甲基三硫醚、甲基吡嗪、苯乙酮、噻唑醇、2-呋喃甲醇等文献报道对虾香味有贡献的化合物。     

The aroma volatile repertoire in strawberry fruit: a review

Aroma significantly contributes to flavor, which directly affects the commercial quality of strawberries. The strawberry aroma is complex as many kinds of volatile compounds are found in strawberries. In this review, we describe the current knowledge of the constituents and of the biosynthesis of strawberry volatile compounds, and the effect of postharvest treatments on aroma profiles. The characteristic strawberry volatile compounds consist of furanones, such as 2,5‐dimethyl‐4‐hydroxy‐3(2H)‐furanone and 4‐methoxy‐2,5‐dimethyl‐3(2H)‐furanone; esters, including ethyl butanoate, ethyl hexanoate, methyl butanoate, and methyl hexanoate; sulfur compounds such as methanethiol, and terpenoids including linalool and nerolidol. As for postharvest treatment, the present review discusses the overview of aroma volatiles in response to temperature, atmosphere, and exogenous hormones, as well as other treatments including ozone, edible coating, and ultraviolet radiation. The future prospects for strawberry volatile biosynthesis and metabolism are also presented. © 2018 Society of Chemical Industry     

Effects of supercritical carbon dioxide on volatile formation from Maillard reaction between ribose and cysteine

BACKGROUND: Supercritical carbon dioxide (SC‐CO₂) technology is being used in an increasing number of food‐manufacturing applications; however, its effect on the Maillard reaction is not well studied. The objective of this study was to investigate the effect of SC‐CO₂ treatment (140 °C, 40 MPa) on the Maillard reaction of an aqueous ribose–cysteine model system under varying pH conditions (5.6, 7.0 and 8.0), with emphasis on the formation of volatile compounds. RESULTS: SC‐CO₂ had a suppressing effect on the browning stages of the reaction under acidic and neutral pH conditions, while it appeared to have an accelerating effect at pH 8.0. Over 70 volatile compounds were positively identified from the headspace of the model system by gas chromatography–mass spectrometry. The volatiles were dominated by sulfur‐containing compounds including thiophenes and fused bicyclic sulfur‐containing compounds under all experimental conditions. Several compounds, including 2‐methyl‐3‐furanthiol, 2‐furanmethanethiol, 3‐thiophenethiol, and 2‐methyl‐3‐thiophenethiol, and one of the intermediates, furfural, were generated in much higher amounts in the SC‐CO₂‐treated samples, especially at alkaline and neutral pH values. CONCLUSION: SC‐CO₂ treatment was inhibitory to the formation of most volatiles in the Maillard reaction, but enhanced the formation of some intermediates and well‐known meaty flavoured compounds. Copyright © 2007 Society of Chemical Industry     

Headspace solid-phase microextraction gas chromatography–mass spectrometry (HS-SPME-GC–MS) determination of volatile compounds in roasted plantains (French sombre and Dwarf Kalapua)

Volatile compounds from roasted plantains (French sombre, AAB) and (Dwarf Kalapua, ABB) at different stages of ripening were evaluated by a gas chromatography–mass spectrometry (GC–MS) with headspace solid-phase microextraction (HS-SPME). A total of 42 volatile compounds were identified in the roasted plantain cultivars. Some of the volatile compounds with high concentration were 2,3-dimethylpyrazine, 2-ethyl-3,5-dimethylpyrazine, (E)-2-hexenal, 2,5-dimethylpyrazine and 2,3-dihydro-5-hydroxyl-6-methyl-(4H)-pyran-4-on respectively. Principal component analysis (PCA) based on the relationships between ripening/quality of volatiles showed that 2-methyl propanol, furfural, 2,5-dimethyl pyrazine, 2,3-butanedione, guaiacol, 2-ethyl-3-methyl pyrazine, 5-, ethyl acetate, 2-pentanol, 3-isobutyl-2-methoxy pyrazine and 7,8-dihydro-β-ionol were considered to contribute significantly to the overall aroma quality of fairly riped (stages 4 & 5) and roasted plantains.     

Evolution of aroma compounds of murtilla fruits (Ugni molinae Turcz) during storage

BACKGROUND: ‘Murtilla’, ‘mutilla’ or ‘murta’ (Ugni molinae Turcz) is a native Chilean species that produces a small berry fruit with a special aroma, whose volatile compounds have not yet been identified. The fruit may be consumed raw and also as jams, juice, canned products, confections and liquor. RESULTS: At the beginning and end of the storage, 24 volatile compounds were identified in murtilla fruit aroma and the concentration of these compounds in murtilla fruit ranged from 1.2 to 250.5 µg kg^?1 fresh weight. Methyl 2‐methyl butanoate, ethyl butanoate, ethyl 2‐methyl butanoate, methyl hexanoate, ethyl hexanoate, methyl benzoate and ethyl benzoate were the major components, all of which have been reported as potent odors in other aromatic fruits. Based on estimated odor activity value, the most potent compound in the murtilla fruit aroma were ethyl hexanoate and 4‐methoxy‐2,5‐dimethyl‐furan‐3‐one. The statistical analysis showed that the storage produced a distinct effect on the same volatile compounds released from the murtilla ecotypes. CONCLUSION: The volatile compounds identified in murtilla fruit aroma, which may be described as fruity, sweet and floral, have been found in other aromatic fruits. Concerning the aroma, the murtilla fruit from ecotype 19‐1 was shown to be the best in cooled storage. Copyright © 2007 Society of Chemical Industry     

The Effect of pH and Temperature on Cabbage Volatiles During Storage

During storage of shredded cabbage, characteristic sulfurous volatile compounds are formed affecting cabbage aroma both negatively and positively. Selected ion flow tube‐mass spectrometry (SIFT‐MS) was used to measure the concentration of cabbage volatiles during storage. The volatile levels of cabbage samples were measured at pH 3.3 to 7.4 at 4 °C for 14 d, and pH 3.3 at 25 °C for 5 d in order to determine the effect of pH and temperature. Aroma intensity, best aroma, freshness, and off odor were evaluated in a sensory test of the samples at 4 °C. The desirable volatile allyl isothiocyanate was lower in high pH samples (pH 7.4 and 6.4), whereas higher concentrations were detected in low pH samples (pH 3.3 and 4.6). Lipoxygenase volatiles, which produce a fresh green and leafy aroma in cabbage, were generated in very low amounts at any pH value. High pH samples generated significantly higher concentrations of off odors such as dimethyl sulfide, dimethyl disulfide, dimethyl trisulfide, and methanethiol. Sensory tests showed that higher pH samples had significantly stronger off odor and lower desirable cabbage aroma than lower pH samples. Thus, sensory results matched the volatile results in that samples at higher pH levels formed the highest amount of undesirable volatiles and the least amount of desirable volatiles. Storage at 25 °C produced similar concentrations of allyl isothiocyanate, but significantly higher levels of off odors, than at 4 °C. Shredded cabbage products should be stored in low pH dressings to minimize formation of off odors and maximize formation of characteristic, desirable cabbage odor.     

Odour‐active compounds in pineapple (Ananas comosus [L.] Merril cv. Red Spanish)

Application of solid‐phase microextraction, simultaneous distillation–extraction and liquid–liquid extraction combined with GC‐FID, GC‐MS, aroma extract dilution analysis, and odour activity value was used to analyse volatile compounds from pineapple (Ananas comosus [L.] Merril cv. Red Spanish) and to estimate the most odour‐active compounds. The analyses led to the identification of ninety‐four compounds, seventy‐two of them were positively identified. Twenty odorants were considered as odour‐active compounds, from which ethyl 2‐methylbutanoate, 2,5‐dimethyl‐4‐hydroxy‐3(2H)‐furanone, 1‐(E,Z,Z)‐3,5,8‐undecatetraene, ethyl 3‐(methylthio)propanoate, 1‐(E,Z)‐3,5‐undecatriene, ethyl hexanoate and methyl hexanoate were the most odour contributors and contribute to the typical pineapple aroma, while the others are responsible for fruity and sweet odour notes.     

Relationships of Sweetness in Lager to Selected Volatile Congeners

Lager is generally brewed to minimise the final sugar content but despite this can have sweet characters. Such flavour notes have been ascribed to concentrations above flavour thresholds of certain volatile congeners: maltol; 4‐hydroxy‐2,5‐dimethyl‐3(2H)‐furanone (HDMF); 4‐hydroxy‐2(5)‐ethyl‐5(2)‐methyl‐3(2H)‐furanone (HEMF); hydroxymethylfurfural (HMF); diacetyl; and specific esters (ethyl acetate, ethyl caproate, ethyl caprylate, and iso amyl acetate). Relationships between scoring of sweetness in lagers and quantitative data on relevant congeners and ethanol were explored. Lagers (23) were scored for sweetness using rank rating and in 18 lagers ten relevant volatile congeners were quantified by gas chromatography. Relationships between sensory and compositional data were modelled. Multiple linear regression was less successful than partial least squares regression (PLS1) based on four principal factors. Calibration values for r²were 0.70 and 0.77, when ester data was excluded and included, and validation values were 0.56 and 0.45, respectively. Prediction was improved to a validation r²= 0.74 when an artificial neural network was used in modelling with the complete compositional data set. It was concluded that in lagers a range of congeners and ethanol contribute in a complex manner to perceptions of sweetness and the relationship with 4‐hydroxyfuranone derivatives merits revaluation.     

模式体系Maillard反应合成热加工肉类(牛肉)风味料的研究

以牛肉酶解物、L 半胱氨酸盐酸盐、DL 丙氨酸、D 木糖、盐酸硫胺素等为模式体系反应制备热加工肉类风味料 ,采用固相微萃取 (SPME) GC MS对反应产物进行分析 ,共分离鉴定出 71种挥发性化合物 ,尤其是分离鉴定出 2 ,5 二甲基 4 羟基 3 (2H) 呋喃酮、2 乙基 4 羟基 5 甲基 3(2H)呋喃酮、甲基吡嗪、2 ,5 二甲基吡嗪、2 ,6 二甲基吡嗪、4,5 二甲基噻唑、2 乙酰基 3 氨基噻吩、3 甲基 2 噻吩羰基醛、甲基 (2 甲基 -3 呋喃基 )二硫醚、反式茴香醚、5 乙烯基 4 甲基噻唑、四氢 3 甲基 1 ,3 二硫醇 (4 ,5 b)呋喃、十六醛等肉香或特征性牛肉风味化合物。     

花生饼粕及花生壳烘烤风味分析

采用顶空固相微萃取和气相色谱-质谱联用技术对不同花生饼粕和花生壳的烘烤风味进行分析,比较不同原料的烘烤风味强弱,并对鉴定出的挥发性风味成分进行主成分分析,明确不同原料烘烤风味的主要风味物质。结果表明:从不同花生饼粕、花生壳的烘烤风味中共鉴定出119种挥发性物质,包括醛类、酮类、烃类、吡嗪类、呋喃类、吡咯类、吡啶类、胺类和其他共9类化合物。根据不同原料烘烤风味的总峰面积进行风味强度对比,低温饼2的烘烤风味强度最高,花生壳烘烤风味强度最弱。其中,花生饼粕中的主要风味物质为吡嗪类、吡咯类、呋喃类和吡啶类等氮氧杂环化合物,而醛类和呋喃类化合物是花生壳中主要的风味物质。通过主成分分析,2,5-二甲基吡嗪、甲基吡嗪、2-乙酰基-3-甲基吡嗪、2-乙基-3-甲基吡嗪和N-甲基吡咯等化合物是烘烤花生饼粕中的主要风味物质,2-戊基呋喃、壬醛、5-甲基呋喃醛、正己醛和癸醛等化合物是烘烤花生壳中的主要风味物质。     

Changes in volatile flavour compounds in field pea cultivars as affected by storage conditions

The impact of storage conditions on volatile flavour profile of field pea cultivars was evaluated. Seeds were kept at 4 °C, room temperature (approximately 22 °C) and 37 °C for 12 months. Headspace solid‐phase microextraction gas chromatography–mass spectrometry was used for extraction and identification of volatile flavour compounds (VFCs). Significant (P < 0.01) differences in the concentration of VFCs were observed during storage. All cultivars kept at 22 and 37 °C had higher mean value of aldehydes compared to those kept at 4 °C. Alcohols, hydrocarbons, ketones, terpenes and esters were higher in samples stored at 4 °C compared to those at higher temperatures. 1‐Hexanol, hexanal, styrene, 2‐butanone, dimethyl sulphide, 3‐carene, ethyl acetate and 2, 3‐diethyl‐5‐methyl pyrazine were the most abundant compounds found in peas. Results from this study could be useful in identifying improved conditions of storage to enhance flavour properties of peas.     

Rapid differentiation of new apple cultivars by headspace solid‐phase microextraction in combination with chemometrical data processing

The aim of this study was to test a combination of automated headspace solid phase‐microextraction gas chromatography (GC) with chemometrical data treatment for the rapid differentiation of enzyme‐inactivated homogenates of new apple cultivars. The four cultivars Pinova, Piflora, Renora and Florina are characterized by different volatile patterns. Differences in the contents of volatiles were especially found for butyl acetate, ethyl butanoate, 2‐methyl butanol, ethyl acetate and 6‐methyl‐5‐hepten‐2‐ol. The used sample preparation method for GC coupled with pattern recognition of chromatograms is a useful tool for rapid and reliable determination of large numbers of samples.     

Chemical changes of thermally sterilized broccoli puree during shelf-life: Investigation of the volatile fraction by fingerprinting-kinetics

For the first time in literature, this study evaluates the potential of a “fingerprinting-kinetics” strategy to investigate how the volatile fraction of thermally sterilized broccoli puree is affected by shelf-life. Samples were stored at four storage temperatures (20 °C, 28 °C, 35 °C and 42 °C). The volatile fraction was analyzed using headspace GC-MS fingerprinting as a function of time and temperature (kinetics). Fingerprinting enabled selection of sulfur-containing compounds (dimethyl sulfide, carbon disulfide, dimethyl pentasulfide, dimethyl trisulfide, bis-(methylthio)-phosphine and methyl (methylthio)methyl disulfide), nitriles (heptanonitrile, 5-methyl-hexanenitrile, hexanenitrile and 5-(methylthio)-pentanenitrile), fatty acid derivatives (octanal and 2-ethyl-1-hexanol), furanic compounds (2-ethylfuran) and Strecker aldehydes (3-methylbutanal) as volatiles significantly changing during shelf-life. In general, most of the volatiles decreased as a function of shelf-life. Next, the suitability of the volatiles (selected by fingerprinting) as markers for accelerated shelf-life testing was investigated. Based on the applied kinetic modelling, 3-methylbutanal was identified as a potential marker.     

Influence of pH on the formation and radical scavenging activity of volatile compounds produced by heating glucose with histidine/tyrosine

In this study, the effect of pH on the volatile generation over reaction time as well as the DPPH radical scavenging activity of volatile MRPs was investigated in the Maillard reaction of glucose (Glc) with tyrosine (Tyr) and histidine (His). Factor analysis showed clearly that volatiles generated in 5-h open system were of similar composition to those in 0.5-h close system regardless of pH level and amino acid, implying higher pressure in close system could accelerate the volatile formation in Maillard reaction. Besides, all volatiles showed increasing tendency over reaction time under different pH levels with the exception of pyrones which decreased with the extension of reaction time at pH = 7 and pH = 9. Furans, phenols and 2-acetylpyrrole that were favored under acidic condition showed larger increase at pH = 5 over reaction time, while other volatiles except pyrones, furans, phenols and 2-acetylpyrrole, which were favored under neutral and alkaline conditions, showed greater increase at pH = 7 and pH = 9 over reaction time. The measurement of DPPH radical scavenging activity of dichloromethane extract obtained from Maillard reaction mixture revealed that volatile MRPs from Glc–Tyr system showed stronger antioxidant activity under alkaline condition, while volatile MRPs from Glc–His system showed greater antioxidant activity under acidic condition.     

Radical scavenging activities of Asterina pectinifera fermented with Cordyceps militaris mycelia

The degradation behavior of L-ascorbic acid (ASA) was investigated under different parameters of temperature, time, and pH. Higher temperatures and longer times accelerated the ASA degradation. Degradation product distributions changed with different pH values. As solution pH of 4.5 was beneficial for formation of uncolored intermediate products with an absorbance maximum at 294 nm. Formation of brown products was promoted at pH values from 5.8 to 6.8 with an absorbance maximum at 420 nm. Under different pH conditions, volatile products formation varied. Furfural and derivatives of furan were primary products due to the effects of pH. The non-enzymatic selfdegradation behavior of ASA was characteristic of first-order kinetics based on a classic dynamic model. Activation energy values varied under different pH values. An ASA degradation mechanism and pathway are proposed.     

MAJOR VOLATILES IN TOASTED CANOLA OIL

Headspace volatiles from 'Alto' canola oil toasted at 240C for 8 min were collected using Tenax ^R TA 60/80 (Supelco Inc., Bellefonte, PA). The Tenax ^R was washed three times with a total of 6 ml of solvent. The solvent extract was concentrated by drying in a hood at room temperature for 6 h. Two μl of concentrated extract were separated on a 30 m DB-1 capillary column (J & W Scientific, Folson, CA) with a Hewlett Packard (HP) 5890A gas chromatograph connected to a HP 5790 mass spectrometer. Volatiles were tentatively identified with a NBS 43 K.1 library by PBM (probability based on matching) search.
Fifty seven peaks were detected by the mass spectrometer. Among those, 50 compounds were tentatively identified. 2-Furancarboxaldehyde, 5-methyl-2-furan carboxaldehyde, 5-(1-methyl ethyl)-1,3-cyclopentadiene, cyclododecane, undecanoic acid, tetradecanoic acid, 1-hexadecanol, hexadecanoic acid, 9-octadecenoic acid, octadecanoic acid, 2,5-dimethyl pyrazine, 3-ethyl-2,5-dimethyl pyrazine, [1,1':3',1"-terphenyl]-1'-ol and [1,1':3',1"-terphenyl]-4'-ol were the major volatile compounds.