Flavor Components Research Articles

Effects of Storage in an Active and Spontaneous Controlled O2/CO2 Atmosphere on Volatile Flavor Components and the Microbiome of Truffles.

This study explored the potential to improve the storage quality and prolong the shelf life of truffles by storing them in a modified atmosphere fresh-keeping box with sealed gas components of Active Modified Atmosphere Packaging (AMAP, 40% O2 + 60% CO2) at 4 °C. During the storage period, a total of 63 volatile components in 10 categories were detected, with aldehydes being the most abundant and the relative content of ethers being the highest. The relative odor activity value and principal component analysis revealed that isovaleraldehyde, 1-octen-3-ol, 1-octen-3-one, and dimethyl sulfide were the characteristic flavor components of fresh truffles. However, 3-methylthiopropionaldehyde and (E, E)-2,4-nonadienal were the components that caused the deterioration of truffle flavor and could potentially serve as markers of truffle decay characteristics. 16S rDNA high-throughput sequencing showed that Leuconostoc and Lactococcus were dominant in the truffle samples stored for 14 days, but the abundance of putrefactive pathogenic bacteria showed an increasing trend in the truffle samples stored for 28 days. During the whole storage period, the common fungi detected in the different treatment groups were Candida and Aspergillus. The relative abundance of the former decreased, while the relative abundance of the latter decreased initially and then increased. The correlation between volatile components and the microbial flora was further analyzed, which indicated that Lactococcus and Lactobacillus had the same contributions to the same flavor, while Pseudomonas and Glutamicibacter had the opposite contributions to the same flavor. The results provide a reference for the storage and preservation of truffles.

Effect of boiled-water-cooking time on quality and characteristic of flavor components in pig large intestines

Fresh pig large intestines have a heavy initial off-flavor and a strong pungent smell that may cause discomfort to the consumer. To examine how boiled-water cooking of the pig large intestines affects the quality characteristics and flavor profiles, changes in shear force, cooking loss, volatile flavor compounds, and other physical and chemical indexes were measured in pig large defatted intestines using gas chromatography-odor-mass spectrometry detector (GC-O-MS), and electronic nose (E-nose) and texture analyzer. The results showed that indole, 3-methylindole, and 4-methylphenol were the characteristic volatile substances that caused visceral off-odor to the pig large intestines. After boiled-water-cooking, the content of acids decreased, while the aldehydes increased. Group B20 boiled for 20 min showed the highest volatile substance content in pig large intestines. However, the contents of the off-odor components 4-methylphenol, indole, and 3-methylindole in the samples decreased by 56.5%, 45.5%, and 20.4%, respectively, after continuous boiling for 10 min. The odor of the late stage samples (mainly after B20) was significantly different from the control group (R0) and those of the early stage of boiling (B0, B5). As cooking time was increased, the texture of intestines became tender, the shear force decreased, and the fat percentage initially decreased before stabilizing. This study provides a theoretical support for the quality change of pig large intestines during heating.

Comparative analysis of asparagus tea processing and flavor component analysis

Blanching plays important roles in shaping the volatile profile of asparagus tea. In this study, the flavor of blanched and unblanched asparagus teas were studied in detail by electronic nose (E-nose), electronic tongue (E-tongue) and gas chromatography-mass spectrometry (GC-MS) coupled with chemometrics methods. Sensory evaluation showed that in blanched asparagus tea, sweet aroma was significant improved, whereas grassy and harsh smell were declined. Linear discriminant analysis (LDA) of the E-nose data showed a clear discrimination between the blanched and unblanched samples. Volatile metabolites analysis showed that blanching treatment generally resulted in a decrease in aldehydes, pyrroles, pyrazines and an increase in ketones and hydrocarbons. Furthermore, styrene, nerylacetone, pentanal, and heptanal were identified as key compounds causing sweet aroma in blanched asparagus teas. While benzothiazole, 2-pentylfuran, naphthalene and several additional compounds are responsible for the green odor in unblanched asparagus teas. The E-tongue and antioxidant activity showed that blanched improved the quality of asparagus tea. These results provided a new insight and scientific basis to improve the processing techniques and quality control for asparagus tea.

Characterization of key aroma compounds and relationship between aroma compounds and sensory attributes in different quality of high temperature Daqu

Daqu quality is determined by its aroma characteristics. In this study, molecular sensory techniques were used to investigate the sensory attributes of Jiangxiangxing high temperature Daqu, resulting in the development of a sensory wheel. A physicochemical and enzymatic analysis of different grades of Daqu revealed notable differences, especially in acidity. Furthermore, the volatile components of various grades of Daqu were investigated with HS-SPME-GC × GC-TOFMS, resulting in the identification of 524 volatile compounds belonging to 11 distinct classes within Daqu. Univariate analysis demonstrated significant differences in flavor components among Daqu samples of diverse quality grades. By employing GC-O-MS techniques and ROAV≥ 0.1, a comprehensive analysis identified a total of 29 key aroma active compounds that contribute to the overall flavor profile of Daqu. Notably, butyl acrylate and (2E)-2-octenal were found to make substantial contributions to the floral and fruity odor, as well as linalool and benzeneacetaldehyde, which were found to make substantial contributions to sweet odor. These compounds significantly enriched the aroma of Daqu and played a crucial role in enhancing the overall flavor quality of Daqu. In conclusion, these results provide a theoretical base for further investigation of different grades of Daqu, as well as the control and improvement of Daqu quality.

GC-MS, GC-IMS, and E-Nose Analysis of Volatile Aroma Compounds in Wet-Marinated Fermented Golden Pomfret Prepared Using Different Cooking Methods.

The cooking method is extremely important for the production of low-salt, wet-marinated, fermented golden pomfret because it strongly influences its flavor components and organoleptic quality. There are also significant differences in flavor preferences in different populations. The present study analyzed differences in the aroma characteristics of wet-marinated fermented golden pomfret after boiling, steaming, microwaving, air-frying, and baking using a combination of an electronic nose, GC-IMS, and SPME-GC-MS. Electronic nose PCA showed that the flavors of the boiled (A), steamed (B), and microwaved (C) treatment groups were similar, and the flavors of the baking (D) and air-frying (E) groups were similar. A total of 72 flavor compounds were detected in the GC-IMS analysis, and the comparative analysis of the cooked wet-marinated and fermented golden pomfret yielded a greater abundance of flavor compounds. SPME-GC-MS analysis detected 108 flavor compounds, and the results were similar for baking and air-frying. Twelve key flavor substances, including hexanal, isovaleraldehyde, and (E)-2-dodecenal, were identified by orthogonal partial least-squares discriminant analysis (OPLS-DA) and VIP analysis. These results showed that the cooking method could be a key factor in the flavor distribution of wet-marinated fermented golden pomfret, and consumers can choose the appropriate cooking method accordingly. The results can provide theoretical guidance for the more effective processing of fish products and the development of subsequent food products.

Effects of Saccharomyces cerevisiae and Kluyveromyces marxianus on the Physicochemical, Microbial, and Flavor Changes of Sauce Meat during Storage

Saccharomyces cerevisiae (S. cerevisiae) and Kluyveromyces marxianus (K. marxianus) are often used as fermenters in yogurt and alcohol, and have been less studied within meat products. The yeasts were added to sauce meat, and the uninoculated group served as a control in this study to examine and compare the changing patterns of physicochemical and flavor characteristics of S. cerevisiae and K. marxianus on sauce meat during storage. The changes in moisture content, aw, pH, thiobarbituric acid reactive substances (TBARS), and other flavor characteristics were measured in sauce meat during the first, second, fourth, and sixth months after production. The following factors were examined: moisture content, aw, pH, TBARS, peroxide value (POV), acid value (AV), soluble protein (SP), free amino acid (FAA), and volatile flavoring compounds. With VIP > 1 and p < 0.05 as the screening conditions, the partial least squares model (PLS-DA) was used to assess the distinctive flavor components in the sausages. The findings demonstrated that the three groups’ changes in sauce meat were comparable during the first two months of storage but differed significantly between the 4th and 6th months. The moisture content, water activity, and pH of the sauce meat decreased gradually with the storage time; TBARS, AV, and FAA increased significantly; SP decreased significantly from 2.61 to 1.72, while POV increased to 0.03 and then decreased to 0.02. The POV and TBARS values of the yeast-infected meat were substantially lower than those of the control group, and the POV and TBARS values of the meat inoculated with S. cerevisiae were particularly decreased (p < 0.05). The POV and TBARS values of SC (S. cerevisiae group) decreased by 49.09% and 40.15%, respectively, compared to CK (the control group) at the time of storage until June. The experimental group (KM: K. marxianus group) significantly increased the SP and FAA values of the sauce meat (p < 0.05) by 32.4% and 29.84% compared to the CK group, respectively. Esters and olefins as well as alcohols and esters were much greater in meat that had been supplemented with S. cerevisiae and K. marxianus than in meat from the control group. In conclusion, inoculating sauce meat with S. cerevisiae can significantly enhance the quality and flavor of sauce meat while it is being stored.

Bamboo shoots improve the nutritional and sensory quality, and change flavor composition of chicken soup

The effect of adding bamboo shoots to stewing on the quality and flavor of chicken soup has never been reported. Therefore, this study investigated the effects of 4 kinds of bamboo shoots on the edible quality, volatile and water-soluble flavor components of Chahua chicken soup. The results showed that adding bamboo shoots changed the sensory and nutritional quality of chicken soup. A total of 62 volatile flavor components were identified by HS-SPME-GC–MS, of which 12 were identified as characteristic volatile flavor components, and 9 were the main reasons for the flavor differences between bamboo shoot chicken soup with blank chicken soup. LC-MS found that after adding bamboo shoots, the differential water-soluble components in chicken soup significantly increased, and most of the increased components have been proven to have physiological functional activity. In conclusion, adding bamboo shoots improved the nutritional and sensory quality, and changed the flavor components of chicken soup.

Unveiling the microbiota of sauce-flavor Daqu and its relationships with flavors and color during maturation.

This study investigated the microbial community in three-color sauce-flavor Daqu (black, yellow, and white) throughout their maturation processes, together with their physicochemical factors, culturable microbes, flavor components, and fermenting vitalities. Results from high-throughput sequencing revealed distinct microbial diversity, with more pronounced variations in bacterial community than in fungal community. Firmicutes and Ascomycota emerged as the most dominant bacterial and fungal phyla, respectively, during maturation. Genus-level analysis identified Kroppenstedia, Virgibacillus, and Bacillus as dominant bacteria in black Daqu, yellow Daqu, and white Daqu, severally, while Thermoascus was shared as the core dominant fungi for these Daqu. Physicochemical factors, particularly acidity, were found to exert a significant impact on microbial community. Kroppenstedtia was the key bacteria influencing the color formation of these Daqu. Furthermore, correlations between dominant microbes and flavor compounds highlighted their role in Daqu quality. Molds (Aspergillus, Rhizomucor, and Rhizopus), excepting Bacillus, played a crucial role in the formation of pyrazine compounds. Consequently, this study offers innovative insights into the microbial perspectives on color and pyrazine formation, establishing a groundwork for future mechanized Daqu production and quality control of sauce-flavor baijiu.

HS-SPME-GC-MS Combined with Orthogonal Partial Least Squares Identification to Analyze the Effect of LPL on Yak Milk's Flavor under Different Storage Temperatures and Times.

Flavor is a crucial parameter for assessing the sensory quality of yak milk. However, there is limited information regarding the factors influencing its taste. In this study, the effects of endogenous lipoprotein lipase (LPL) on the volatile flavor components of yak milk under storage conditions of 4 °C, 18 °C and 65 °C were analyzed via headspace solid-phase microextraction gas chromatography-mass spectrometry (HS-SPME-GC-MS) combined with orthogonal partial least-squares (OPSL) discrimination, and the reasons for the changes in yak milk flavors were investigated. Combined with the difference in the changes in volatile flavor substance before and after the action of LPL, LPL was found to have a significant effect on the flavor of fresh yak milk. Fresh milk was best kept at 4 °C for 24 h and pasteurized for more than 24 h. Principal component analysis (PCA) and orthogonal partial least squares discriminant analysis (OPLS-DA) were employed to characterize the volatile components in yak milk under various treatment conditions. Twelve substances with significant influence on yak milk flavor were identified by measuring their VIP values. Notably, 2-nonanone, heptanal, and ethyl caprylate exhibited OAV values greater than 1, indicating their significant contribution to the flavor of yak milk. Conversely, 4-octanone and 2-heptanone displayed OAV values between 0.1 and 1, showing their important role in modifying the flavor of yak milk. These findings can serve as monitoring indicators for assessing the freshness of yak milk.

Effects of different extraction methods on the release of non-volatile flavor components in shiitake mushroom (Lentinus edodes)

Shiitake mushroom is a highly nutritious and delicious edible fungus with a unique flavour, making it popular among consumers globally. In this study, the effects of different extraction methods on the release of non-volatile flavour substances in shiitake mushroom were investigated using e-tongue, high performance liquid chromatography (HPLC), and principal component analysis (PCA). The results of pretreatment showed that hot air drying at 60 ℃ had higher umami intensity. On the basis of it, enzymatic hydrolysis was found to be beneficial for the release of soluble sugars (alcohols), organic acids, and free amino acids, especially umami, sweet amino acids like Glu, Ser, and Thr. Double enzymatic hydrolysis had higher umami intensity. On the other hand, cooking was beneficial to the release of 5′-nucleotides, with 5′-AMP and 5′-GMP being key flavour substances in high-pressure cooking. In conclusion, enzymatic hydrolysis can increase the ratio of umami and sweet amino acids, and high-pressure cooking is the best way to promote the release of 5′ -nucleotides. The findings of this study provide a theoretical foundation for the development of shiitake mushroom condiment.

Effect of lipase and lipoxygenase on lipid metabolism and the formation of main volatile flavour compounds in fermented fish products: a review

SummaryLipid metabolism due to lipid hydrolysis and oxidation considerably contributes to the final product quality of fermented fish products and especially impacts its flavour. Lipase and lipoxygenase (LOX) are key enzymes involved in lipid metabolism. Endogenous lipases (lipase from fish muscle and adipose tissue) and/or exogenous lipases (lipase from microorganisms, the added lipase) catalyse the hydrolysis of lipids, producing numerous free fatty acids. LOX in fish gills and skin tissues plays an important role in lipid oxidation. During the catalysis by LOX, polyunsaturated fatty acids having cis, cis‐1,4‐pentadiene structure are oxidised, finally leading to the generation of flavour precursors or compounds such as alcohols, aldehydes, ketones, esters and acids. The addition of lipase effectively enhances the content of acidic components. Simultaneously, fermented fish products with a start culture capable of producing both lipase and LOX exhibit higher levels of flavour and aroma. In this process, the collaborative action of lipase and LOX generates a rich array of volatile flavour components. This review offers a comprehensive overview of the distinct functions and effects of both endogenous and exogenous lipase, along with LOX, in fermented fish products, as well as their roles in lipid metabolism. The study also explores their effects on the main volatile flavour compounds of fermented fish products. Moreover, the article discusses the prospects of applying lipase and LOX in fermented fish products, highlighting some limitations in current research and offering recommendations for future studies.

Comparative study of volatile flavor compounds in green onion (Allium fistulosum L.) processed with different cooking methods

The characteristic aroma of green onions was effective in masking the fishy smell in dishes and enhancing the overall flavor. The study aimed to isolate and identify the volatile compounds present in raw, boiled, fried, and roasted green onions using gas chromatography-ion migration spectrometry (GC-IMS). The relative odor activity value (ROAV) was determined, and principal component analysis (PCA) was used to analyze the elements. A total of 64 volatile compounds were finally identified from the green onions and classified as sulfur compounds (19 species), aldehydes (14 species), alcohols (12 species), ketones (13 species), esters (5 species), and furans (1 species). The results of fingerprint analysis indicated that the unique flavor of raw green onions could be attributed to sulfur compounds such as allyl methyl trisulfide and diethyl trisulfide. The unique flavor of boiled green onions can be attributed to the presence of aldehydes such as E-2-octenal and E-2-heptenal. The characteristic flavor components of fried green onions were 3-methyl-butanol and 2-methyl-butanol. Roasted green onions contained ketones, including 2-Butanone and 3-Pentanone, which contributed to their unique flavor. The results of the principal component analysis (PCA) indicated that the flavor of boiled and fried green onion was similar, while a significant difference was observed between raw and roasted green onions.

Study on the dynamic change of volatile components of white tea in the pile-up processing based on sensory evaluation and ATD-GC–MS Technology

The pile-up processing has a great impact on the flavor of white tea. To investigate the effects of the volatile accumulation of white tea with different piling thickness treatments, tea leaves from different thickness treatments were subjected to sensory quantitative description analysis and ATD-GC–MS detection in this study. As a result, 122 volatile components were identified from white tea with different treatments. A total of 8 key compounds, including isovaleraldehyde, isobutyraldehyde, 2-methyl-butanal, 1-octene-3-ol, linalool, pentanoic acid, hexanal and 1-hexanol were screened out using multivariate statistical analysis, which were characteristic components of grassy, floral-fruity, pekoe aroma and sweet flavors. The results of the selected key characteristic volatile compounds were consistent with the sensory quantitative description. The aroma of mid-pile dried tea (MD) was exhibited a harmonious and pleasant overall flavor. This study provides a novel insight into the accumulation of volatile during the withering step of white tea production.

Bioturbation effect of artificial inoculation on the flavor metabolites and bacterial communities in the Chinese Mao-tofu fermentation

A comparison between artificially inoculated Mao-tofu (CC) and naturally fermented Mao-tofu (MM) indicated that artificially adding Mucor plasmaticus to Mao-tofu dramatically enhanced the essential amino acid (EAA) content, as well as umami and sweet amino acids. Gas chromatography-tandem mass spectrometry (GC–MS/MS) analysis revealed that phenol (3.226 μg/g), 1-octen-3-ol (5.031 μg/g), ethyl heptanoate (1.646 μg/g), and indole (3.422 μg/g) were the key flavor components in Mao-tofu. Unlike MM, CC displayed a substantial increase in esters and a considerable decrease in foul odor substances, including sulfur-containing compounds and indole. Lactococcus raffinolactis, Enterobacter sp. 638, and Streptococcus parauberis KCTC 11537 represented the key bacterial species altering the amino acids and flavor of Mao-tofu according to PacBio single-molecule real-time (SMRT) sequencing and correlation analysis. This study presents the technical feasibility of artificially inoculating Mao-tofu to regulate the core bacterial communities and control the quality of fermented soybean products.

Sensory-Guided Establishment of Sensory Lexicon and Investigation of Key Flavor Components for Goji Berry Pulp.

Many customers prefer goji berry pulp, well-known for its high nutritional content, over fresh goji berries. However, there is limited research on its sensory lexicon and distinctive flavor compounds. This study focused on developing a sensory lexicon for goji berry pulp and characterizing its aroma by sensory and instrumental analysis. Sensory characteristics of goji berry pulp were evaluated by our established lexicon. A total of 83 aromatic compounds in goji berry pulp were quantified using HS-SPME-GC-Orbitrap-MS. By employing OAV in combination, we identified 17 aroma-active compounds as the key ingredients in goji berry pulp. Then, we identified the potentially significant contributors to the aroma of goji berry pulp by combining principal component analysis and partial least squares regression (PLSR) models of aroma compounds and sensory attributes, which included 3-ethylphenol, methyl caprylate, 2-hydroxy-4-methyl ethyl valerate, benzeneacetic acid, ethyl ester, hexanal, (E,Z)-2,6-nonadienal, acetylpyrazine, butyric acid, 2-ethylhexanoic acid, 2-methyl-1-propanol, 1-pentanol, phenylethyl alcohol, and 2-nonanone. This study provides a theoretical basis for improving the quality control and processing technology of goji berry pulp.

The improvement of Hovenia acerba-sorghum co-fermentation in terms of microbial diversity, functional ingredients, and volatile flavor components during Baijiu fermentation.

The quality of Baijiu was largely affected by raw materials, which determine the flavor and taste. In the present study, organic acids, polyphenols, volatile flavor components and microbial community in Hovenia acerba-sorghum co-fermented Baijiu (JP1) and pure sorghum-fermented Baijiu (JP2) were comprehensively analyzed. Organic acids, polyphenols and volatile flavor components in JP1 were more abundant than JP2. The abundance and diversity of bacteria and fungi in JP1 was higher than that in JP2 in the early stage of fermentation, but presented opposite trend in the middle and late stages. Leuconostoc, Lentilactobacillus and Issatchenkia were dominant genera in JP1. Whereas, Cronobacter, Pediococcus and Saccharomyces occupied the main position in JP2. Lentilactobacillus and Issatchenkia were positively related to most of organic acids and polyphenols. Pseudomonas, Rhodococcus, Cronobacter, Pediococcus, Brucella, Lentilactobacillus, Lactobacillus, Saccharomycopsis, Wickerhamomyces, Aspergillus, Thermomyces and unclassified_f-Dipodascaccae were associated with the main volatile flavor components. The main metabolic pathways in two JPs exhibited the variation trend of first decreasing and then increasing, and the metabolism activity in JP1 were higher than that in JP2. The results demonstrated the introduction of Hovenia acerba improved the functional ingredients and volatile flavor components, which is helpful for the quality promotion of Baijiu. This study identified the key microorganisms and discussed their effect on organic acids, polyphenols and volatile flavor components during the fermentation of Baijiu with different raw materials, providing a scientific basis for the development and production of high-quality Baijiu.

Characterization of flavor volatiles in raw and cooked pigmented onion (Allium cepa L) bulbs: A comparative HS-GC-IMS fingerprinting study

Variations in volatile flavor components in pigmented onion bulbs (purple, white, and yellow) before and after cooking were characterized by headspace gas chromatography-ion migration spectrometry (HS-GC-IMS) to investigate their odor traits. Results showed that 39 and 45 volatile flavor compounds were identified from pigmented onion bulbs before and after cooking via the HS-GC-IMS fingerprinting, respectively. Sulfurs (accounting for 50.65%–63.42%), aldehydes (13.36%–22.11%), and alcohols (11.32%–17.94%) ranked the top three prevailing compound categories in all pigmented onions (both raw and cooked). Compared to the raw colored onion bulbs, the relative proportion of sulfurs in cooked onions decreased, whereas the relative proportion of alcohols, esters, pyrazines, and furans increased. Two reliable prediction models were established through orthogonal partial least squares-discriminant analysis (OPLS-DA), and 8 and 22 distinctive odor compounds were sieved out by variable importance in projection (VIP>1.0) as volatile labels, respectively. Both principal component analysis (PCA) and clustering heatmap exhibited favorable distinguishing effects for various pigmented onion bulbs before and after cooking. These results might offer insights into understanding the odor characteristics of different pigmented onions.

Characterization and discrimination of volatile organic compounds and α-glucosidase inhibitory activity of soybeans (Glycine max L.) during solid-state fermentation with Eurotium cristatum YL-1

In this study, the influence of solid-state fermentation (SSF) using probiotic Eurotium cristatum on the change of volatile organic compounds (VOCs) and α-glucosidase inhibition activity of soybeans was investigated. A total of 46 VOCs were characterized via headspace gas chromatography-ion mobility spectrometry (HS-GC-IMS), the majority of which were aldehydes (17), alcohols (10), and ketones (7). SSF by E. cristatum drastically affected the flavor characteristics of soybeans, and the levels of unpleasant beany flavor components, such as hexanal-D, 1-octen-3-ol, 1-hexanol-D, 1-hexanol-M, heptanal-M, 1-pentanol, heptanal-D, and 2-pentyl furan were all substantially decreased by 50% after 15 days of SSF, while volatiles with floral, caramel, and desirable flavors such as pentanal-D, methylpropanal, 2-propanol, and propyl acetate drastically (p < 0.05) increased by 1.1-, 19.2-, 3.6-, and 2.6-fold, respectively. Key aroma-active compounds analysis revealed that 18 VOCs (ROAV, relative odor activity value ≥ 1) play a great role in shaping the flavor characteristics of the soybean samples. After 15 days of SSF, the ROAV values of methylpropanal, 2-propanol, and propyl acetate drastically (p < 0.05) increased to 8.48, 63.88, and 11.29, respectively, which greatly contributed to the desirable flavor characteristics of fermented soybeans. Furthermore, E. cristatum greatly improved the α-glucosidase inhibitory activity of soybean by 22.4% after 15 days fermentation, which was closely correlated with the accumulated phenolic compounds during SSF. Molecular docking showed that genistein and daidzein have high binding affinity for α-glucosidase active sites, primarily driven by hydrogen bonds and hydrophobic interactions. These results demonstrated that soybeans fermented with E. cristatum substantially improved the flavor characteristics and α-glucosidase inhibitory effect, and were greatly helpful to promote the application of soybeans in food products.

Multi-omics Analysis of Volatile Flavor Components in Pacific Chub and Spanish Mackerel during Freezing using GC–MS–O

This study employed gas chromatography-mass spectrometry with olfactory (GC–MS–O) and multi-omics methods to investigate the changes in volatile flavor compounds during the freezing process of Pacific chub mackerel (Scomber japonicus) from Japan and China, and Spanish mackerel (Scomberomorus niphonius). A total of 18 volatile flavor compounds were identified, and significant differences in volatile flavor components were observed among samples frozen for 1 week, 1 year, and 2 years. The results of the Partial least squares regression (PLSR) indicated that the fishy odor was correlated with independent variables such as fatty acids (FA 22:4, FA 28:6, FA 24:4), differentially expressed genes (Gene.2425 (NDUFA5), Gene.38 (GPX1), and Gene.2844 (DAD1)). Classification and regression tree (CART) analysis revealed that the peak area values of fatty acids (FA 22:5, FA 20:4) and fatty acid esters of hydroxy fatty acids (FAHFA 18:0/22:3) were the main differentiating factors for fishy odor perception.

Chemical, Functional and Sensory Properties of Ogi–Mango Mesocarp Flour

Ogi, a cereal fermented paste was produced from maize fortified with mango mesocarp. This would definitely result in increased protein intake for consumers since most of the grain protein would still be present in the ogi (except for what is leached during steeping and in the wash water). However, there was decrease in fat and protein content of the blends as the substitution increases. The slight variation in carbohydrate content may be due to alterations in other components (protein, fat, ash, fibre and moisture). The study also recorded reduction in viscosity as the mango mesocarp flour increased. The decrease in viscosity may be ascribed to the reduction of fermented maize flour which consequently reduced the starch content of the blends. The lower viscosity observed in the flour indicated that it could be used as a weaning food. Also the hygroscopicity of the flour increased with mango mesocarp flour inclusion. This may be ascribed to the presence of more hydrophilic carbohydrate from reducing sugars in the mango mesocarp flour. Βeta-carotene increased with increase in mango mesocarp inclusion. Sensory evaluation of the samples was carried out using semi-trained panel consisting of ogi-pap consumers who are familiar with with ogi-pap quality. The control (Sample A) was rated low; in all; the attributes increased significantly (P≤ 0.05) as the percentage of mango mesocarp flour increased. The blends with higher percentages of mango mesocarp flour were most preferred. This implies that incorporation of mango mesocarp flour could improve the sensory attributes of fermented maize flour. The preference for the taste and flavour of the blends increased significantly (P≤ 0.05) with increase in percentage of mango mesocarp flavor. The increase in preference may be attributed to the sugar and flavor components of mango fruits respectively.