Characterization of Key Aroma Compounds in Raw and Thermally Processed Prawns and Thermally Processed Lobsters by Application of Aroma Extract Dilution Analysis

Difference comparison of characteristic aroma compounds between braised pork cooked by traditional open-fire and induction cooker and the potential formation cause under electromagnetic cooking

The characteristic aroma compounds of braised pork were identified through molecular sensory science and PLSR analysis, and the difference between two cooking methods, traditional open-fire (BPF) and induction cooker (BPC), was compared. Seventeen aroma compounds with odor activity values (OAVs) > 1 were identified in both samples. BPF revealed higher OAVs for most of the aroma compounds compared to BPC, and the higher aroma quality. Aroma recombination and omission experiments confirmed that twelve aroma compounds significantly contributed to the characteristic aroma of braised pork, and eight compounds such as hexanal, (E)-2-octenal, and methanethiol were further confirmed as important contributors by PLSR analysis. Furthermore, PLSR analysis clarified the role of aldehydes such as hexanal, (E)-2-octenal, and (E,E)-2,4-decadienal in contributing to fatty attribute, whereas methanethiol was responsible for the meaty aroma. These characteristic aroma compounds mainly derived from lean meat due to its high content of phospholipids, and the exogenous seasonings contributed to the balanced characteristic aroma profile of braised pork by altering the distribution of these characteristic aroma compounds. Variations in heating parameters affected the formation of lipid oxidation and Strecker degradation products, which might explain aroma discrepancy between braised pork cooked by two methods with different heat transfer efficiencies.

Creating alternative seafood flavour from non-animal ingredients: A review of key flavour molecules relevant to seafood

This review summarises current knowledge of the molecular basis for flavour profiles of popular seafood types (crustacean (crab, lobster, prawn, etc.), mollusc (oyster, squid, etc.), oily fish (salmon, sardine, etc.) and white fish (barramundi, turbot, etc.)), and provides a foundation for formulating improved plant-based seafood alternative (PBSA) flavours. Key odour-active volatile molecules were identified from a systematic review of published olfactometry studies and taste-active compounds and macronutrient profiles of different seafood species and commercial PBSAs from nutrition databases were compared. Ingredients commonly used in commercial BPSAs and new potential sources of flavouring agents are evaluated. While significant challenges in replicating seafood flavour and texture remain, this review provides some insights into how plant-based ingredients could be applied to improve the acceptability of PBSAs.

Comparison of volatile aroma compounds in commercial surimi and their products from freshwater fish and marine fish and aroma fingerprints establishment based on metabolomics analysis methods

Understanding the differences in odors of freshwater and marine fish surimi and their products is important for the quality control of surimi products. Aroma compounds in silver carp surimi and three kinds of marine fish surimi and their products were identified by gas chromatography-mass spectrometry/olfactometry, and aroma fingerprints of them were established based on metabolomics analysis methods. Silver carp surimi and surimi products showed the highest "fresh fish" and "grassy, earthy" notes, while the marine fish surimi and their products presented a strong "sea breeze-like" odor. Five Br-containing compounds (sea breeze-like) were identified in the marine fish samples. The aroma fingerprints showed that the odor compositions of freshwater and marine surimi/surimi products were divided into two categories, and the marine fish surimi and their products also showed differences in odors. Furthermore, four commercial surimi and their products could be distinguished according to 33 and 28 differential aroma components, respectively.

Contribution of Key Odorants from Skins, Seeds, and Stems to the Aroma of Chardonnay Marc: A Valuable Coproduct of the Wine Industry

Chardonnay marc, a co-product of the wine making industry, has recently garnered attention due to its health-promoting properties and is growing in popularity as a potential healthy and flavorful food ingredient. While previous studies have characterized the odorants in marc skins and identified the key odorants in marc seeds, the key odorants in the skins and stems and the contribution of each component to the whole marc aroma remains unknown. In this study, 27 odorants were identified in marc stems using solvent-assisted flavor evaporation and aroma extract dilution analysis. Four odorants were quantitated employing stable isotope dilution assays, and odor activity values (OAVs) were calculated. An odor simulation model prepared using odorants with OAVs > 1 sensorially matched the aroma of the marc stems. Omission studies showed that 3-methylnonane-2,4-dione, ethyl octanoate, oct-1-en-3-one, (2E,4E)-deca-2,4-dienal, (2E,4E)-nona-2,4-dienal, β-ionone, linalool, hexanal, HDMF, and 3-(methylsulfonyl)propanal were the key odorants in marc skins, while hexanal and 3-methylnonane-2,4-dione were the key odorants in marc stems. Mass balance studies suggested that the skins were the main contributor to the hay, floral, and fruity attributes of the whole marc, the seeds contributed mostly to the fatty attribute, and the stems had a minor contribution.

Sotolon and (2E,4E,6Z)-Nona-2,4,6-trienal Are the Key Compounds in the Aroma of Walnuts

Fresh kernels of the walnut tree (Juglans regia L.) show a characteristic and pleasant aroma, the molecular basis of which was unknown. The application of an aroma extract dilution analysis resulted in 50 odor-active compounds. Among them, 37 had not been reported as fresh walnut kernel volatiles before, including the two odorants with the highest flavor dilution factors, namely, fenugreek-like smelling 3-hydroxy-4,5-dimethylfuran-2(5H)-one (sotolon) and oatmeal-like smelling (2E,4E,6Z)-nona-2,4,6-trienal. Quantitations revealed 17 odorants with concentrations in the walnuts that exceeded their odor threshold concentrations. Aroma reconstitution and omission experiments finally showed that the characteristic aroma of fresh walnuts is best represented by a binary mixture of sotolon and (2E,4E,6Z)-nona-2,4,6-trienal. Of both, the natural concentration was ∼10 μg/kg. Further sensory studies showed that the walnut character is intensified when their concentrations are in parallel increased to ∼100 μg/kg. This finding may guide the future breeding of new walnut cultivars with improved aroma.

Characterization of the Key Aroma Constituents in Fried Tilapia through the Sensorics Concept

The object of this study was tilapia fish that were fried in soybean oil. Volatile compounds were extracted from the fish by ASE-HVE and were studied by GC-O-MS and the AEDA analysis method. A total of 30 aroma compounds were initially determined, and these compounds contribute to the aroma of fried tilapias. The key volatile compounds in fried tilapia were quantitatively analyzed by GC-MS, and the volatile compounds in soybean-fried tilapia were studied by flavor recombination and deletion experiments. Trimethylamine, hexanal, 2,3-dimethylpyrazine, dimethyl trisulfide, trans-2-octenal, 2,3-dimethyl-5-ethylpyrazine, (E)-2-nonenal, 2-propyl-pyridine, and (E,E)-2,4-decadienal were finally determined to be the key volatile compounds in soybean-fried tilapia.

Insight into the evolution of aroma compounds during thermal processing of surimi gel from silver carp (Hypophthalmichthys molitrix)

This study aimed to investigate the formation of odor properties in surimi products by exploring changes in aroma compounds and their precursors at setting (40 °C) and gelling (90 °C) stages during surimi gel formation by solvent-assisted flavor evaporation, gas chromatography-mass spectrometry, and ultra performance liquid chromatography. Results revealed a gradual increase in the contents of most aldehydes, alcohols, and phenolics during surimi gel formation, while a decrease in the contents of (E)-2-pentenal, (E)-2-hexnenal, (Z)-4-heptenal, (E)-2-heptenal, and most ketones at gelling stage. During thermal process, 50 % decrease was observed in the contents of some unsaturated fatty acids (palmitoleic acid, oleic acid, etc.), and the contents of tyrosine, phenylalanine, methionine, isoleucine, and leucine decreased significantly (P < 0.05) at gelling stage. Moreover, lipoxygenase activity reached 4.19-4.81 U/min·g at setting stage. Overall, amino acid degradation and lipid auto-oxidation mainly occurred at gelling stage to promote the formation of related compounds.

Key Aroma Compounds in Roasted White Kołuda Goose

Aroma-active compounds in the roasted leg meat of White Kołuda goose were assayed by gas chromatography-olfactometry, using aroma extract dilution analysis and solvent-assisted flavor evaporation. Quantitation, recombination-omission tests, and sensory evaluation were carried out. Thirty aroma compounds, for which odor activity values (OAVs) were calculated and for which the flavor dilution factors were greater than or equal to 1, were identified. The concentration of aroma compounds ranged from 0.06 to 633 (μg/kg). The highest OAVs (>1024) were for 2-furfurylthiol, 2-acetyl-1-pyrroline, and 1-octen-3-one. Nine key aroma compounds were: 2-furfurylthiol, 2-acetyl-2-thiazoline, 1-octen-3-one, 2-phenylethanethiol, 4,5-dimethyl-3-hydroxy-2(5H)-furanone, 4-hydroxy-2,5-dimethyl-3(2H)-furanone, (E,E)-2,4-decadienal, 2-acetyl-1-pyrroline, and 3-(methylthio)propanal. The intensity of the dominating roasted, meaty/broth, and fatty notes in the recombination model consisting of the key odorants were rated (10-point scale) at 4.6-5.8 points, relative to the original roasted goose (5.2-6.2). The aroma compounds defined predominantly the meaty, roasted, and fatty flavors during the descriptive sensory evaluation of the roasted goose meat.

Comparative Characterization of Aroma Compounds in Silver Carp (Hypophthalmichthys molitrix), Pacific Whiting (Merluccius productus), and Alaska Pollock (Theragra chalcogramma) Surimi by Aroma Extract Dilution Analysis, Odor Activity Value, and Aroma Recombination Studies

Aroma compounds in three surimi samples, made from freshwater silver carp (Hypophthalmichthys molitrix) and saltwater Pacific whiting (Merluccius productus) and Alaska pollock (Theragra chalcogramma), were characterized by aroma extract dilution analysis, odor activity value, and odor recombination study. Results demonstrated that the most potent aroma-active compounds in the surimi were hexanal, (Z)-4-heptenal, (Z)-4-decenal, (E,Z)-2,6-nonadienal, (E,E)-2,4-nonadienal, (E,Z)-2,4-decadienal, (E,E)-2,4-decadienal, (E,E,Z)-2,4,6-nonatrienal, (E,Z,Z)-2,4,7-tridecatrienal, and (E)-4,5-epoxy-(E)-2-decenal, contributing fishy, green, oily, or metallic odors. The other aroma contributors in surimi were 1-octen-3-one, 1-octen-3-ol, dimethyl disulfide, dimethyl trisulfide, and methional. 2-Acetyl-1-pyrroline, giving a typical popcorn note, could also be an important aroma contributor as a result of the high flavor dilution factor. Pacific whiting and Alaska pollock surimi samples both had higher levels of dimethyl trisulfide and methional, whereas the silver carp surimi sample had more (E,Z)-2,4-decadienal. In general, the silver carp surimi sample had more aldehydes contributing stronger "river water, fishy" and "grassy, green" aromas. In contrast, saltwater surimi showed stronger "sea breeze-like" and "sulfur-like" odors.

Identification of characteristic aroma compounds in raw and thermally processed African giant snail (Achatina fulica)

Background

Food flavor appreciation is one of the first signals along with food appearance and texture encountered by consumers during eating of food. Also, it is well known that flavor can strongly influence consumer’s acceptability judgment. The increase in the consumption of snail meat across the world calls for the need to research into the aroma compounds responsible for the distinctive aroma notes of processed snail meat.

Results

The odorants responsible for the unique aroma notes in thermally processed giant African snail meats were evaluated by means of aroma extract dilution analysis (AEDA), gas chromatography–olfactometry (GC–O) and odor activity values (OAVs) respectively. Results revealed significant differences in the aroma profiles of the raw and thermally processed snail meats. Whilst the aroma profile of the raw snail meat was dominated with the floral-like β-ionone and β-iso-methyl ionone, sweaty/cheesy-like butanoic acid, and the mushroom-like 1-octen-3-one, the boiled and fried samples were dominated with the thermally generated odorants like 2-methylpyrazine, 2,5-dimethylpyrazine, 2-acetylthiazole and 2-acetylpyridine.

Conclusion

Finally, results have shown that sotolon, 2-acetyl-1-pyrroline, 2-furanmethanethiol, 2-methylbutanal, 1-octen-3-one, octanal, furanone, 2-methoxyphenol, 2-acetylpyridine, 2-acetylthiazole, and 2-methylpyrazine contributed to the overall aroma of the thermally processed snail meat.

Comparative Evaluation of Key Aroma-Active Compounds in Raw and Cooked Red Mullet (Mullus barbatus) by Aroma Extract Dilution Analysis

Raw red mullet (Mullus barbatus) and its cooked samples, obtained from steam and oven cooking, were subjected to aroma and key odorant analysis for the first time using GC-MS-O. The extraction of the aroma compounds was carried out by the direct solvent extraction-solvent assisted flavor evaporation (DSE-SAFE) method. Principal component analysis (PCA) was used to determine the relations between cooking processes and fish aroma compounds. By applying the aroma extract dilution analysis (AEDA), 8 and 13 aroma-active compounds were detected in raw and cooked fish samples, respectively. The most prominent differences between raw and cooked fish samples were as follows: 3-hydroxybutan-2-one, 2,3-octadienone, (E,E)-2,4-heptadienal, linalool, γ-butyrolactone, 1-methylpyrrolidin-2-one, 2H-furan-5-one and pyrrolidin-2-one were only detected in cooked samples while hexanal and 2-phenoxyethanol in only raw fish samples. GC-MS-O results clearly indicated that cooking process results in the development of characteristics and pleasant aroma of red mullet samples due to the lipid oxidation. The most dominant aroma-active compound in the cooked fish samples was the 1-octen-3-ol which is responsible for the mushroom-like odor.

Evaluation of Key Aroma Compounds in Processed Prawns (Whiteleg Shrimp) by Quantitation and Aroma Recombination Experiments

In our previous study on the aroma compounds of heated prawn meat, the main odorants in blanched (BPM) and fried prawn meat (FPM), respectively, were characterized by means of gas chromatography-olfactometry and aroma extract dilution analysis. In this follow-up study, these aroma compounds were quantified by means of stable isotope dilution assays, and odor activity values (OAV; ratio of concentration to odor detection threshold) were calculated. Results revealed 2-acetyl-1-pyrroline and (Z)-1,5-octadien-3-one as the most potent odor-active compounds in both prawn samples. In FPM, as compared to BPM, higher OAVs were determined for 2-acetyl-1-pyrroline, 2-acetyl-2-thiazoline, 3-methylbutanal, 3-(methylthio)propanal, phenylacetaldehyde, 3-hydroxy-4,5-dimethyl-2(5H)-furanone, 4-hydroxy-2,5-dimethyl-3(2H)-furanone, 2,3-diethyl-5-methylpyrazine, and trimethylpyrazine. Aroma recombination experiments corroborated that the overall aroma of the blanched as well as the fried prawn meat, respectively, could well be mimicked by the set of key odorants quantitated in this study.