Flavour production in plant cell cultures of basmati rice (Oryza sativa L)

Callus cultures of naturally flavoured rice (Oryza sativa var 370) called basmati were obtained on Murashige and Skoog medium with 2,4-dichlorophenoxyacetic acid and kinetin. There was a perceptible basmati flavour in fresh callus. The volatile flavour components of basmati rice and callus were obtained by steam distillation-solvent extraction and were analysed on GC-MS. A qualitative comparison of volatile flavour components of callus cultures and natural basmati rice was also made. The results show the presence of 29 major compounds in rice and 23 in callus. The identified compounds include hydrocarbons, ketones, aldehydes, alcohols and esters. This demonstrated the potential of callus of basmati rice for flavour development.     

Changes in flavour compound profiles of precooked pork after reheating (warmed-over flavour) using gas chromatography–olfactometry–mass spectrometry with chromatographic feature extraction

The unclear components and complex evaluation indicators affect the effectiveness of inhibition methods for warmed-over flavour (WOF). To evaluate the main components of WOF, the changes in flavour compound profiles of precooked pork after reheating were investigated quantitatively by using gas chromatography–olfactometry–mass spectrometry with chromatographic feature extraction. A total of 49 volatile compounds were identified, including 22 aroma-active compounds that were primarily derived from lipid oxidation. Fifteen key volatile compounds were obtained that represented principal components of the changes in flavour compound profiles, of which 1-octen-3-ol, (Z)-2-octenal and (E,E)-2,4-decadienal made the greatest contribution to the principal components and achieved odour activity value (OAVs) >1.0 after reheating. The results showed that the three compounds are the dominant volatile compounds and potential evaluation indicators of WOF. This study provides a further understanding of the components of WOF in precooked pork and an effective analysis method of gas chromatography.     

Effects of growth hormones and maturity of the fruits on the callus culture of guava (Psidium guajava) fruits using response surface methodology

Guava, a tropical fruit, is valued for its aroma and is used in many fruit products. Earlier work from this laboratory has shown that the expression of the flavour as a secondary metabolite through tissue culture in vitro is possible. In the present study an attempt has been made to maximise the callus culture growth through optimisation of the hormonal combinations of indole acetic acid (IAA), 2,4-dichlorophenoxy acetic acid (2,4D) and kinetin (Kn). The effect of using fruits of different maturity was also assessed. The study of the complex interactions of the growth hormones and the identifications of the optimal hormonal levels have been carried out using appropriate design of experiments which are specially framed for such purposes. Simplex optimisation techniques were used to obtain the optimum levels of these hormones for highest relative growth in the experimental region. The results indicate that callus culturing with fruits before reaching climacteric with MS medium supplemented with 0.01 mg litre^?1 of IAA and 2,4D and 2.87 mg litre^?1 of Kn results in a high relative growth of 8.97 for the callus.     

Volatile components of mangaba fruit (Hancornia speciosa Gomes) at three stages of maturity

The effect of stage of maturity on the volatile components of mangaba fruit (Hancornia speciosa Gomes) growing at Sergipe State, Brazil, was investigated at three different stages. The volatile profile obtained by hydrodistillation, using a Clevenger-type apparatus, was analysed by GC–FID and GC–MS. It was possible to identify 33 compounds in the immature fruits, such as 1-octen-3-ol (2.8%), (Z)-linalool oxide (9.1%), (E)-linalool oxide (6.3%), linalool (16.1%), 2-phenylethanol (4.5%), α-terpineol (5.5%), geraniol (3.1%), hexadecanal (2.5%) and octadecanol (2.7%); 34 compounds in the fruits at the intermediate stage, such as ethyl propanoate (4.1%), n-propyl acetate (11.1%), 3-methyl-3-buten-1-ol (6.8%), 2-methyl propyl acetate (2.5%), furfural (18.6%), (Z)-3-hexenol (3.2%), 1-hexanol (2.4%), 3-methyl-3-buten-1-yl acetate (5.4%), (Z)-3-hexen-1-yl acetate (2.9%), n-hexyl acetate (3.3%), (Z)-linalool oxide (3.9%), (E)-linalool oxide (2.4%), linalool (3.8%), 2-phenylethanol (2.8%) and α-terpineol (2.5%); and 32 components in the mature fruits, such as 3-hydroxy-2-butanone (9.1%), 2,4,5-trimethyl-1,3-dioxolane (6.8%), 3-methyl-3-buten-1-ol (12.1%), 3-methyl-1-butanol (5.2%), furfural (8.3%), 3-methyl-1-butanyl acetate (8.8%) and 3-methyl-3-buten-1-yl acetate (28.2%).     

Volatile flavour compounds in suspension culture of Agastache rugosa Kuntze (Korean mint)

For the production of volatile flavour compounds from Agastache rugosa Kuntze (Korean mint) suspension culture, callus was obtained from the leaves of A rugosa. Cell growth of A rugosa suspension culture was improved when cells were cultivated in Murashige and Skoog medium supplemented with 50 g l^?1 sucrose and 1 mg l^?1 2,4‐dichlorophenoxyacetic acid. Volatiles were isolated from a 15‐day‐old suspension culture by liquid–liquid continuous extraction and identified by gas chromatography/mass spectrometry. 3‐Hydroxy‐2‐butanone was the most abundant compound, followed by 2,4,5‐trimethyl‐3‐oxazoline, 1,2,4‐trimethylbenzene and 1,3‐butanediol. However, the volatile profile of the suspension culture was totally different from that of the intact plant. Fourteen aroma‐active compounds were detected by aroma extract dilution analysis. The most potent aroma‐active compounds representing characteristic aroma of A rugosa suspension culture were 2,3‐butanedione (buttery/cheese), (E,Z)‐2,6‐nonadienal (cucumber/melon) and (E,Z)‐2,6‐nonadien‐1‐ol (cucumber/sweet). Some alcohols and unknown compounds are thought to contribute to the wine‐like aroma characteristics of A rugosa suspension culture. Through a time course study, A rugosa suspension culture was revealed to have an inverse relationship between cell growth and flavour production. © 2001 Society of Chemical Industry     

Characterization of odor-active compounds in three varieties of ciruela (Spondias purpurea L.) fruit

The aroma-active compounds present in tree ripened fruits of ciruela (Spondias purpurea L.) cultivars Chi abal, Campech abal, and Ek abal were isolated by means of simultaneous distillation solvent extraction and solid-phase microextraction and analyzed by gas chromatography-mass spectrometry. Application of odor activity values (OAV) afforded 22 compounds in higher amounts than their threshold concentrations (OAVs >1). Results of the identification experiments in combination with the OAVs suggested that methyl 3-methylbutanoate, ethyl butanoate, ethyl 2-methylbutanoate, ethyl 3-methylbutanoate, ethyl hexanoate, hexyl acetate, with fruity odor notes; (E)-2-hexenal, (Z)-3-hexen-1-ol, (E)-2-hexen-1-ol, 1-hexanol, and (Z)-3-hexenyl acetate, with grassy odor notes, and limonene (citrus-like) were the potentially important common odorants in all ciruela cultivars. Clear differences in the OAVs of some odorants between each of the cultivars suggested that they contributed to the unique sensory profiles of the individual cultivars.     

Biochemical studies with garlic (Allium sativum) cell cultures showing different flavour levels

Garlic (Allium sativum L) cell cultures, unorganised white as well as organised green callus, revealed a total of five amino acid precursors (methyl, propyl, allyl, cysteine sulphoxides) and two unidentified ninhydrin-positive compounds. All the five compounds were hydrolysable by alliin lyase to yield pyruvic acid. Their relative concentration varied in the cultured systems and the explant. The total flavour substrate index in globular white callus and semi-differentiated green callus was 4 and 13% respectively of the original explant. In contrast to the substrate levels, the specific activity of alliin lyase enzyme showed half the original activity of the garlic bulb explant. The relationship between intermediary metabolism and flavour formation was studied in these cultures with the help of ¹⁴C-glucose and ¹⁴C-methionine. The incorporation of ¹⁴C label was lower in the protein, carbohydrate and lipid fractions with a concomitant higher incorporation in the volatile fraction of semi-differentiated cultures, whereas this trend was reversed in the white globular callus. ¹⁴C Conversion to the flavour fraction was much lower in the in-vitro cultures when compared with the garlic bulb. The activity of some enzymes such as amino transferase, malate dehydrogenase, polyphenol oxidase, peroxidase, and alkaline phosphatase was higher in the cultured cells than in garlic bulb. There were differences also in the protein, free amino acid profiles and peroxidase isozymes of garlic cell cultures and the original explant.     

Effects of explant source,culture medium: Strength and growth regulators on the in-vitro propagation of three Jamaican yams: (Dioscorea cayenensis,D trifida and d rotundata)

Explants of tuber, meristem and vines from three widely cultivated yam species in Jamaica—D cayenensis, D rotundata and D trifida—were examined for their responses to mineral media strength, inorganic ammonium and growth regulator supplements. Tuber pieces (5mm³) showed some positive growth responses but did not produce in-vitro plantlets on all the media tested. Meristem tips of D trifida grew rapidly on basal media (BM) supplemented with either 0.1 mglitre^?1 6-benzylamino purine (BAP) and 0.01 mg litre^?1indole butyric acid or 0.2 mg litre^?1 BAP and 1.0 mg litre^?1 naphthalene acetic acid (NAA) producing plantlets by 28 weeks. The nodal explants grew rapidly with plantlets obtained from all the cultivars within 4 weeks. Use of young, vigorously growing vines of 8 weeks or less, as explant source, gave low contamination levels (16–25%) in culture when sterilised for 30 min in 200 g litre^?1 NaOCl in the case of D trifida and 300 g litre^?1 NaOCl in the case of D cayenesis prior to culturing. Initiation of growth was optimal when explants were taken from monopodial vines grown in October or January and placed on BM supplemented with 0.5 mg litre^?1 BAP (BM0.5BAP). Addition of 0.5 mg litre^?1 kinetin to the BM or 0.05 mg litre^?1 NAA to BM0.5BAP depressed shoot production, while 5.0 mg litre^?1 kinetin increased swelling of the nodal region in explants from sympodial shoots and from vines grown in March. The results suggest that nodal segments excised from young, fast growing vines of these species are the best explant source for the purpose of commercial micropropagation.     

Study of the aroma compounds of rose apple (<Emphasis Type="Italic">Syzygium jambos</Emphasis> Alston) fruit from Brazil

Volatiles of the headspace and total aqueous extract from the rose apple fruit were investigated by gas chromatography (GC)–flame ionization detection, GC–mass spectrometry and GC–olfactometry/aroma extract dilution analysis O/AEDA). The headspace fraction was rich in low boiling compounds, while medium and high volatility components predominated in the total aqueous extract. GC–O/AEDA revealed that hexanal, 3-penten-2-one, hexanol, (Z)-3-hexen-1-ol, linalool, isovaleric acid, benzyl alcohol, 2-phenylethylalcohol and (E)-cinnamaldehyde were potent odorants contributing to the headspace aroma. Thus, they might be related to the first odour impression of the fruit. Other potent volatiles, such as caproic and phenylacetic acids, methyl-(E)-cinnamate and (E)-cinnamyl alcohol were identified in the total aqueous extract, only. These results indicated that some volatiles, with medium and high boiling points, might also contribute to the overall rose apple flavour. Besides them, volatiles with lower odour potency, such as 7-octen-4-ol, acetic acid, 2-octen-1-ol and cinnamic acid, could have some additional effect for the overall fruit aroma.     

Effect of hot-air drying on flavour compounds of bell peppers (Capsicum annuum)

The influence of hot-air drying on the composition of both volatile and non-volatile flavour compounds of different Dutch bell pepper cultivars was investigated. Contents of glucose, fructose, ascorbic, citric, and oxalic acid decreased significantly after drying, while the levels of sucrose, malic, fumaric, and cis-aconitic acid increased. Glucose, fructose and ascorbic acid probably participate in Maillard reactions during heating. Different effects of drying could be distinguished on the composition of volatile compounds. The majority of these compounds evaporated during drying. Some compounds were partly retained in the dried bell peppers, whereas others disappeared completely. Gas chromatography-sniffing port analysis revealed that compounds with mainly “fresh” odour notes like lettuce/grassy/green bell pepper ((Z-2-3-hexenal), fruity/almond ((E)-2-hexenal), fruity (octanal), lettuce/green bell pepper ((Z)-3-hexenol), and grassy/green bell pepper ((Z)-2-hexenal) decreased or disappeared after drying. Another group of compounds increased or were formed during drying, like 4-octen-3-one, (E)-2-heptenal, (E)-2-octenal, (E,Z)- and (E,E)-2,4-heptadienal, decanal, and (E)-2-nonenal; most are known as autoxidation products of unsatu-rated fatty acids. The increased levels of 2-methylpropionic and 2- and 3-methylbutyric acid, 2-metlhylpropanal, and 2- and 3-methylbutanal seemed to be due to Strecker degradation. Gas chromatography-sniffing port analysis showed that the latter three compounds had distinct cacao, sweaty, and spicy odour characteristics.     

Potent odorants causing the warmed-over flavour in boiled beef

Summary The flavour compounds showing higher odour units resulting from peroxidation of unsaturated fatty acids were analysed comparatively in freshly boiled beef and in a stored (48 h, 4° C) sample exhibiting warmed-over flavour. The results obtained by aroma extract dilution analysis revealed that this flavour was mainly caused by hexanal, 1-octen-3-one, (E)- and (Z)-2-octenal, (Z)-2-nonenal, (E, E)-2,4-nonadienal andtrans-4,5-epoiiy-(E)-2-decenal.

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Intensive Geruchsstoffe des Warmed-over Flavour (WOF) von gekochtem Rindfleisch

Zusammenfassung Die Aromastoffe mit hohen Aromawerten, die aus der Peroxidation ungesättigter Fettsäuren hervorgehen, wurden in frisch gekochtem Rindfleisch und in einer gelagerten (48 h, 4 °C) Probe mit WOF analysiert. Ein Vergleich der Ergebnisse von Aromaextraktverdünnungsanalysen ergab, daß der WOF hauptsächlich durch Hexanal, 1-Octen-3-on, (E)- und (Z)2-Octenal, (Z)-2-Nonenal, (E, E)-2,4-Nonadienal sowietrans-4,5-Epoxy-(E)-2-decenal verursacht wird.

     

Induction of crocin and crocetins in callus cultures of gardenia jasminoides ellis

Callus was initiated from immature ovary portion of flower of Gardenia jasminoides Ellis on Murashige and Skoog (MS) medium (1962) supplemented with 2,4‐dichlorophenoxyacetic acid (2 mgl^?1) and kinetin (0.5 mgl^?1). Callus on subculture onto MS medium, with reduced nitrate and phosphate levels and supplemented with indole‐3‐butyric acid (1 mgl^?1) and kinetin (1 mgl^?1) induced yellowish pigmented callus when incubated in dark at 25+2° C. The extracts of yellowish callus when analysed by TLC and HPLC showed the presence of crocin and crocetins. Both crocin and crocetins were at low levels in Gardenia callus as compared to Gardenia fruit or Saffron stigma.     

Sorption of flavour compounds in aqueous solution into polyethylene film

Sorption of flavour compounds by the polyethylene (PE) liner of laminated pouches (PET/Al/PE) containing a flavour solution has been studied. The solution contained 43 volatile compounds (each 2 μl litre^?1) in sugar ester solution (3 g litre^?1). The distribution ratios of the flavour compounds for sorption into various PE liners increased with carbon chain length of the flavour compounds from 0.01 to 0.1 for alcohols, from 0.03 to 1.23 for aldehydes, from 0.02 to 5.77 for aliphatic esters and from 0.11 to 11.6 for benzoates. In each series (all straight-chain compounds) the distribution ratios increased about threefold for each methylene group, but in the compounds composed of 11 or more carbon atoms the increment was less or negative. The distribution ratio for a given PE film was proportional to the film thickness. The distribution ratios increased with decreasing crystallinity of the PE film and the results for the films of different crystallinities suggested the existence of an impermeable boundary region surrounding the crystalline material amounting to about 20% of its volume.     

Changes in salted yoghurt during storage

The study was conducted to determine the gross chemical composition and concentrations of free fatty acids (FFAs) and volatile compounds of salted yoghurt made from indigenous goat's milk. The effects of some chemical properties on sensory attributes of salted yoghurt were also studied. Changes in FFAs (P < 0.01) and volatile compounds were statistically significant (P < 0.05) during storage. The most abundant FFAs were 9‐octadecenoic (C_18:1), hexadecanoic (C₁₆), tetradecanoic (C₁₄) and decanoic (C₁₀) acids, respectively. Ethanol and ethyl acetate were principal volatile compounds through the end of storage period. The storage period affected the intensity of flavour attributes and overall flavour score of salted yoghurt (P < 0.05). According to factor analysis result, chemical compounds including volatiles, FFAs up to C₁₄, tyrosine and titratable acidity, and flavour attributes explained 86.50% and 55.33% of total variance, respectively.     

Characterization of volatile compounds in Fen‐Daqu – a traditional Chinese liquor fermentation starter

Fen‐Daqu is a saccharifying agent and fermentation starter for the production of Chinese liquor Fen (alcoholic spirit) and Fen traditional vinegar. The volatile compounds produced at seven incubation steps were analysed by HS‐SPME‐GC‐MS. A total of 83 major volatile compounds were identified, including 23 esters, 8 acids, 24 alcohols, 18 ketones and aldehydes, 6 pyrazines and 4 acetals. Data obtained by HS‐SPME‐GC‐MS were subjected to principal component analysis. The trajectory plots of volatile compounds in Fen‐Daqu samples obtained during successive steps of incubation were revealed. The major compounds that contributed to discrimination were hexanal, (E)‐2‐octenal, (Z)‐2‐octen‐1‐ol, nonanoic acid, 1‐octanol, 2‐decen‐1‐ol, hexyl acetate, (E)‐2‐octen‐1‐ol, acetic acid, ethyl acetate, phenylethyl alcohol, ethyl alcohol, octanoic acid, 1‐octanol, 3‐methyl‐2‐buten‐1‐ol and pyrazines. Copyright © 2012 The Institute of Brewing & Distilling     

SPME-GC-MS detection of volatile compounds in apricot varieties

Aroma compounds of the eight Malatya apricot cultivars, six cultivars grown in the same breeding conditions from different locations and one hybrid cultivar were determined using SPME-GC-MS technique. In general, total concentration (sum of identified and unidentified peaks) of aroma compounds in Malatya apricot cultivars were lower than those others. Total concentration of aroma compounds were found to be in the range of 514 and 6232 μg/kg fresh weight. The main volatiles of apricot cultivars were aldehydes, alcohols, acetates, esters, terpenes and acids. Among these compounds; ethanol, hexanal, hexyl acetate, (Z)-3-hexenyl acetate, (E)-2-hexenyl acetate, 1-hexanol, (Z)-3-hexenol and (E)-2-hexen-1-ol, were present in all cultivars studied at certain levels.     

In vitro culture of Pandanus amaryllifolius and enhancement of 2‐acetyl‐1‐pyrroline,the major flavouring compound of aromatic rice,by precursor feeding of L‐proline

Shoots, plantlets and semi‐differentiated callus (SDC) cultures of Pandanus amaryllifolius capable of producing high levels of basmati rice flavour were established in vitro using Murashige and Skoog nutrient medium. A total of 10% of the initial explants responded to produce shoot cultures in the presence of benzylamino purine (BAP) (0.5 mg L^?1) and glutamine (100 mg L^?1). Leaf explants and basal portions of shoots produced SDC whereas elongated in vitro shoots could be continuously multiplied, using BAP (1.5 mg L^?1) and kinetin (Kn) (1.0 mg L^?1), and rooted in half‐strength medium for ex vitro cultivation leading to a process of micropropagation. Steam‐distillation extraction (SDE) followed by gas chromatography‐mass spectrometry (GC‐MS) analysis of various cultured organs and spent liquid medium used for SDC revealed the presence of 2‐acetyl‐1‐pyrroline (2‐AP) to various extents. This 2‐AP compound has been identified as the major flavouring compound of scented basmati and other scented rice varieties. 2‐AP was found to be highest, on a fresh weight basis, in SDC (19.7 mg kg^?1) on the 40th day, whereas in vitro roots, shoots and field leaves (of one‐year‐old plant) had lower levels of 15, 6.8 and 14 mg kg^?1, respectively. Further enhancement of 2‐AP in SDC using precursor was possible by feeding into medium 1 mmol L^?1 of L ‐proline where a highest level of 21.67 ppm of 2‐AP accumulated on the seventh day whereas a higher level of 2 mmol L^?1 of L ‐proline suppressed 2‐AP levels. The present report is the first on the tissue culture studies of P. amaryllifolius where continuous production of plantlets as well as synthesis of high levels of 2‐AP has been documented. Copyright © 2005 Society of Chemical Industry     

Characterisation of odour-active compounds in aged rum

The volatiles of rum matured in oak casks were carefully isolated by solvent extraction followed by solvent-assisted flavour evaporation. Among the 116 volatile compounds identified by GC-MS, seven of them were found for the first time in rum. Application of the aroma extract dilution analysis (AEDA) on the volatile fraction revealed 18 odour-active areas in the flavour dilution factor range of 32-1024. On the basis of the quantitative data and odour thresholds in 35% ethanol (v/v), the odour activity values (OAV; ratio of concentration to odour threshold) were calculated. Nineteen aroma compounds showed OAVs >1, among which ethanol, (E)-β-damascenone, ethyl butanoate, ethyl hexanoate, vanillin, (Z)-oak lactone, ethyl 2-methylpropanoate, 1,1-diethoxyethane, ethyl 2-methylbutanoate, 3-methylbutyl acetate, ethyl octanoate, ethyl decanoate, 2-phenylethyl acetate, 2-phenylethanol, 2-methoxyphenol, 4-ethyl-2-methoxyphenol, 4-propyl-2-methoxyphenol, γ-nonalactone, and eugenol showed the highest values and should be considered as the most odour-active compounds.     

Compounds from Angelica keiskei with NQO1 induction, DPPH scavenging and α-glucosidase inhibitory activities

A LC-MS method, which GSH was used as substrate, was employed to reveal the compounds with NQO1 induction activity from Angelica keiskei. Some compounds, proposed as isobavachalcone, xanthoangelol and 4-hydroxyderricin, have NQO1 induction activity. To make the actual structures and bioactivities of these compounds clear, 23 compounds, including above mentioned compounds and two new compounds 4-hydroxy-3,5,5-trimethyl-4-(1,2,3-trihydroxybutyl)cyclohex-2-enone (18) and (Z)-2-(3-hydroxypent-1-ynyl)-3-(non-1-enyl)oxiran-2-ol (23), were isolated from the 95% ethanol extract of A. keiskei. The bioassay results suggested the compounds had notable NQO1 induction activity. The radical scavenging and α-glucosidase inhibition activities of the isolated compounds were also tested. Compounds (E)-1-(2,4-dihydroxy-3-(3-methylbut-2-enyl)phenyl)-3-(4-hydroxyphenyl)prop-2-en-1-one (1), (E)-1-(3-((E)-3,7-dimethylocta-2,6-dienyl)-2,4-dihydroxyphenyl)-3-(4-hydroxyphenyl)prop-2-en-1-one (2), 1-(3-hydroxy-10,13-dimethyl-2,3,4,7,8,9,10,11,12,13,14,15,16,17-tetradecahydro-1H-cyclopenta[α]phenanthren-17-yl)ethanone (17), 4-hydroxy-3,5,5-trimethyl-4-(1,2,3-trihydroxybutyl)cyclohex-2-enone (18) could scavenge DPPH radical by more than 20%. Compounds (E)-1-(2,4-dihydroxy-3-(3-methylbut-2-enyl)phenyl)-3-(4-hydroxyphenyl)prop-2-en-1-one (1), (E)-1-(3-((E)-3,7-dimethylocta-2,6-dienyl)-2,4-dihydroxyphenyl)-3-(4-hydroxyphenyl)prop-2-en-1-one (2), (E)-1-(2-hydroxy-4-methoxy-3-(3-methylbut-2-enyl)phenyl)-3-(4-hydroxyphenyl)prop-2-en-1-one (3), 7-hydroxy-6-(3-methylbut-2-enyl)-2H-chromen-2-one (5), 10-hydroxy-8,8-dimethyl-2-oxo-9,10-dihydropyrano[6,5-H]chromen-9-yl)-3-methylbut-2-enoate (9), 2-(4-hydroxyphenyl)-7-methoxy-8-(3-methylbut-2-enyl)-2,3-dihydrochromen-4-one (16), (10S,15R,Z)-10,15-dihydroxyheptadeca-8,16-dien-11,13-diynyl acetate (20), (3R,8S,Z)-heptadeca-1,9-dien-4,6-diyne-3,8-diol (21) exhibited excellent α-glucosidase inhibition activity.     

Effect of storage time and heat processing on the volatile profile of Senegalese sole (Solea senegalensis Kaup, 1858) muscle

The effect of heat treatment and the presence or absence of fish skin on the volatile composition of Senegalese sole muscle was studied. The volatile profile of Senegalese sole at different storage periods was also evaluated. All samples were analysed by HS-SPME–GC–IT/MS and subjected to sensory evaluation. As expected, cooking enhanced the production/liberation of volatile compounds. Fish with the skin present, after cooking, had higher levels of sulphur compounds, 2-nonanone, ethyl octanoate and lower contents of hexanol and heptanol than skinned fish; moreover, the samples with the skin had a better overall sensory acceptability. During storage, changes on the volatile composition of Senegalese sole samples were found. The major differences were obtained after 2 weeks of storage. Compounds such as hexanal, heptanal, octanal, decanal, (E)-2-hexenal, (E)-2-decen-1-al, (E,Z)-2,6-nonadienal, benzaldehyde, 4-ethyl-benzaldehyde, 1-penten-3-ol, heptanol and (E)-2-octen-1-ol decreased after 2 weeks of storage, and other compounds, such as 3-methyl-1-butanal, 2-methyl-1-butanal, 2-heptanone, dimethyl trisulphide, dimethyl tetrasulphide and 2-methyltetrahydrothiophen-3-one increased. These differences were confirmed by sensory evaluation. Principal component analysis was applied to the chemical data.