Volatile Component Profiles Research Articles

Development of hydro-distillation extraction and macroporous resin enrichment method for GC–MS chemical profiling of volatile components in the dried root of Gentiana dahurica Fisch

The dried root of Gentiana dahurica Fisch. has an intensive flavour, which suggests the presence of volatile compounds. Thus, this study aimed to develop an effective extraction method for GC–MS profiling of volatile compounds of G. dahurica. Hydro-distillation and subsequent resin enrichment (HDRE) was developed and applied to the analysis of G. dahurica in comparison with simultaneous distillation and extraction (SDE), and ultrasonic assisted dichloromethane extraction (uDCM). The major components were azulene (33.83%), 1-hexanoic acid (14.19%) and octanoic acid (11.39%) in the HDRE; octanoic acid (17.24%), nonanoic acid (13.29%) and 2,4-di-t-butylphenol (12.73%) in the SDE; and α-amyrin (25.05%), β-amyrin acetate (15.11%) and β-amyrone (4.61%) in the uDCM. Moreover, the HDRE extract was shown to have certain antimicrobial activity against four bacterial strains. Thus, the HDRE method is a promising sample preparation method for GC-MS chemical profiling of volatile components of the dried roots of medicinal plants.

Effect of refrigeration and reheating on the lipid oxidation and volatile compounds in silver carp surimi gels.

As unsaturated and saturated aldehydes, ketones are known to be responsible for off-odors in surimi products, and they are mainly derived from lipid oxidation. Because surimi-based products are rich in unsaturated fatty acids, they are prone to producing off-odors during the refrigeration and reheating processes, which are common treatments for leftovers. The present study investigated the color, lipid oxidation productions, fatty acid profiles and volatile components in surimi gels during refrigeration at 4 °C for 3 days with multiple reheating. The results revealed that the accumulation rate of hydroperoxides was higher in the refrigeration stage, whereas the decomposition rate was higher during reheating in surimi gels. Both refrigeration and reheating treatments promoted conjugated diene values, acid values and carbonyl values. Nevertheless, reheating treatment decreased tohiobarbituric acid reactive substances and whiteness. The contents of unsaturated fatty acids, especially α-linolenic acid, arachidonic acid, eicosapentaenoic acid and docosahexaenoic acid, were reduced, whereas the contents of saturated fatty acids increased during refrigeration and multiple reheating. The unsaturated fatty acids were lost as a result of their oxidative deterioration. The volatile components profile showed that the accumulation of volatile components mainly occurred in the refrigeration stage. Multivariate data analysis was utilized to further clarify whether the off-odors in surimi gels were mainly generated in refrigeration. Refrigeration and reheating both contributed to lipid oxidation and the generation of volatile compounds in surimi gels, but the off-odors were mainly generated during refrigeration. This research provides a novel understanding of the formation of food odors in processing. © 2024 Society of Chemical Industry.

Identification of volatile compounds and evaluation of certain phytochemical properties of Turkish propolis.

The purpose of this study was to assess volatile component profiles and the antioxidant activity of propolis samples from eight different locations in Türkiye. α-Pinene, β-pinene, 3-carene, limonene, 2-acetylfuran, benzaldehyde, acetic acid, benzoic acid, longifolene, isopentyl acetate, m-cymene, styrene, and δ-cadinene were the most common volatile components found in the most of propolis samples. Principal component analysis (PCA) and hierarchical cluster analysis were performed on the gas chromatography-mass spectrometry (GC-MS) data to identify trends and clusters in the propolis samples. As a result of the PCA, the common components in all propolis were m-cymene, decanal, α-pinene, limonene, pinocarvone, benzaldehyde, and butanoic acid. The samples had 2,2-diphenyl-1-picrylhydrazyl radical (DPPH) inhibition activity ranging from 19.2% to 92.5% and 2,2'-azinobis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) values ranging from 480 to 1370 μM trolox/g extract. The total phenolic content (TPC) ranged from 10,900 to 34,033 mg GAE/100 g. Compared with butylated hydroxytoluene (BHT) (control), all but one of the propolis samples exhibited higher DPPH activity. In addition, ABTS levels of propolis extracts were higher than those of BHT. These results unequivocally show that Turkish propolis has remarkable antioxidant qualities, which makes it a viable option for addition to food and medicine products.

Effects of heat treatment on the profile of volatile flavor components in bamboo shoots

The effects of different heat treatment conditions (105, 110, and 120 °C; 10, 20, 30, 40, and 50 min) on the flavor profiles of bamboo shoots were investigated using headspace/solid-phase microextraction-gas chromatography/mass spectrometry/olfactometry-odor activity value (HS/SPME-GC/MS/O-OAV) and sensory analysis. Results indicated noticeable differences in the amount and rate of changes in both original and newly produced flavor components in bamboo shoots at different temperatures. The retention rates of hexanal at 105 °C, 110 °C, and 120 °C were 8.55–34.41%, 7.28–34.32%, and 5.22–11.08%, respectively, whereas (E)-2-hexenal, (E, E)-2,4-heptadienal, (E, Z)-2,6-nonadienal, 1-hexanol, 1-octen-3-ol and 2-pentylfuran were mostly lost after heat treatment. The content of three lipid oxidation compounds (octanal, nonanal, and decanal) increased 75.59–500.67%, while the content of newly generated Maillard reaction compounds (e.g. methional, furfural) increased (0–12.58 μg/kg) with heating temperature and time. Sensory analysis indicated that the bamboo shoots heated at 110 °C for 30 min had the best overall flavor. These findings suggested that moderate heat treatment could eliminate some grassy and mushroom flavors from bamboo shoots, enhancing their sweet flavor. This improvement could be favorable for the consumer acceptance of heat-processed bamboo shoots.

Quality differences and profiling of volatile components between fermented and unfermented cocoa seeds (<i>Theobroma cacao</i> L.) of Criollo, Forastero and Trinitario in China

Quality differences and profiling of volatile components between fermented and unfermented cocoa seeds (<i>Theobroma cacao</i> L.) of Criollo, Forastero and Trinitario in China

Physicochemical characteristics and volatile profile of novel lemon varieties, Minimon and Jeramon

Although most lemons are imported into Korea, their consumption is increasing. Development of domestic varieties of Jeramon and Minimon is currently underway in an effort to meet the increasing demand for fresh lemons. In this study, an analysis of the physicochemical characteristics of Jeramon and Minimon, including their flavor components and antioxidant properties, was conducted. The results revealed that these new varieties of Korean lemon can be regarded as good sources of antioxidants and phytochemicals. Compared to Sunkist, the most consumed lemon variety in Korea, Minimon contained more than twice as much β-cryptoxanthin, and the content of L-ascorbic acid was more than three-four-fold higher in both Minimon and Jeramon. In addition, results from measurement of DPPH and ABTS radical scavenging activities indicated that Jeramon extract exhibited the highest antioxidant activity. In the volatile profile analysis, the profiles of volatile components showed high similarity among the three lemon samples, and the composition ratio was largely dominated by terpenoids. A markedly higher ratio of d-limonene and thymol was detected in the Minimon variety compared with that in the other two varieties. Collectively, the findings from this study on Korean lemon varieties provide a basis as well as valuable guidance for breeding domestic lemon varieties.

Analysis of Volatile Compounds and Flavor Fingerprint Using Gas Chromatography-Ion Mobility Spectrometry (GC-IMS) on Crassostrea gigas with Different Ploidy and Gender.

In this study, GC-IMS was used to analyze the volatile component and flavor profiles of Crassostrea gigas individuals of different ploidy and gender. Principal component analysis was used to explore overall differences in flavor profiles, and a total of 54 volatile compounds were identified. The total volatile flavor contents in the edible parts of tetraploid oysters were significantly higher than in diploid and triploid oysters. The concentrations of ethyl (E)-2-butenoate and 1-penten-3-ol were significantly higher in triploid oysters than in diploid and tetraploid oysters. In addition, the volatile compounds propanoic acid, ethyl propanoate, 1-butanol, butanal, and 2-ethyl furan were significantly higher in females than in males. The volatile compounds p-methyl anisole, 3-octanone, 3-octanone, and (E)-2-heptenal were present in higher levels in male than in female oysters. Overall, different ploidy and gender of oysters are connected with different sensory characteristics, providing new insights for understanding the flavor characteristics of oysters.

Study on molecular mechanism of volatiles variation during Bupleurum scorzonerifolium root development based on metabolome and transcriptome analysis.

Bupleurum scorzonerifolium Willd. is a medicinal herb. Its root has a high content of volatile oil (BSVO), which shows a variety of biological activities. Currently, BSVO in the injectable form is used for treating fever in humans and livestock. The yield and quality of volatile oils depends on the developmental stages of plants. However, the changes in BSVO yield and quality during root development in Bupleurum scorzonerifolium and the underlying molecular regulatory mechanisms remain unclear. This knowledge gap is limiting the improvement in the quality of BSVO. In the present study, B. scorzonerifolium root was collected at germinative, vegetative, florescence, fruiting and defoliating stages. The yield of BSVO, metabolic profile of volatile components and transcriptome of root samples at various developmental stages were comprehensively determined and compared. BSVO continuously accumulated from the germinative to fruiting stages, and its level slightly decreased from the fruiting to defoliating stages. A total of 82 volatile components were detected from B. scorzonerifolium root, of which 22 volatiles were identified as differentially accumulated metabolites (DAMs) during the root development. Of these volatiles, fatty acids and their derivatives accounted for the largest proportion. The contents of most major volatiles were highest at the fruiting stage. A large number of differentially expressed genes (DEGs) were detected during B. scorzonerifolium root development, of which 65 DEGs encoded various enzymes and transcription factors regulating the biosynthesis of fatty acids and their derivatives. In further analysis, 42 DEGs were identified to be significantly correlated with DAMs, and these DEGs may be the key genes for the biosynthesis of volatiles. To the best of our knowledge, this is the first study to comprehensively report the changes in the composition and content of volatiles and underlying mechanism during B. scorzonerifolium root development. This study provided important reference for future studies to determine the harvest time of B. scorzonerifolium roots and improve the quality of BSVO.

Untargeted metabolites profiling of volatile and non-volatile components of Egyptian lotus (Nelumbo nucifera Gaertn.) using UHPLC/PDA/ESI-MS and solid-phase microextraction (SPME) GC/MS in relation to its antiaging and anti-inflammatory effects

Nelumbo nucifera Gaertn. is a unique member of the family Nymphaeaceae, and one of the most important industrial crops with a cultural and medicinal value, especially in the traditional herbal medicines. The beautiful scent of its pink flowers had been used in many cosmetic preparations, but rarely investigated. The goal of this study was to characterize N. nucifera flower aroma profile using solid-phase microextraction coupled with GC/MS. A total of 33 volatile compounds belonging to several classes were identified with cineole reported for the first time and likely to contribute to its aroma. Untargeted metabolites profiling of non-volatile components in leaves, flowers, and seeds was attempted using high-resolution ultra-performance liquid chromatography-mass spectrometry analysis. UPLC-MS. MS-based profiling provided an annotation of more than 60 secondary metabolites with two newly reported glycoalkaloids alongside with floral anthocyanins. Principal component analysis of the UPLC-MS dataset revealed that flowers exhibited a distinct metabolome compared to seeds and leaves. Ultimately, flower extract exhibited a promising anti-aging and anti-inflammatory activities providing a new insight into lotus flower incorporation in the industrial cosmetic formulations.

Differentiation of Mountain- and Garden-Cultivated Ginseng with Different Growth Years Using HS-SPME-GC-MS Coupled with Chemometrics.

Although there are differences in the appearance of Mountain-Cultivated Ginseng (MCG) and Garden-Cultivated Ginseng (GCG), it is very difficult to distinguish them when the samples are processed to slices or powder. Moreover, there is significant price difference between them, which leads to the widespread adulteration or falsification in the market. Thus, the authentication of MCG and GCG is crucial for the effectiveness, safety, and quality stability of ginseng. In the present study, a headspace solid-phase microextraction gas chromatography mass spectrometry (HS-SPME-GC-MS) coupled with chemometrics approach was developed to characterize the volatile component profiles in MCG and GCG with 5-,10-,15-growth years, and subsequently to discover differentiating chemical markers. As a result, we characterized, for the first time, 46 volatile components from all the samples by using the NIST database and the Wiley library. The base peak intensity chromatograms were subjected to multivariate statistical analysis to comprehensively compare the chemical differences among the above samples. MCG5-,10-,15-years and GCG5-,10-,15-years samples were mainly divided into two groups by unsupervised principal component analysis (PCA), and 5 potential cultivation-dependent markers were discovered based on orthogonal partial least squares-discriminant analysis (OPLS-DA). Moreover, MCG5-,10-,15-years samples were divided into three blocks, and 12 potential growth-year-dependent markers enabled differentiation. Similarly, GCG5-,10-,15-years samples were also separated into three groups, and six potential growth-year-dependent markers were determined. The proposed approach could be applied to directly distinguish MCG and GCG with different growth years and to identify the differentiation chemo-markers, which is an important criterion for evaluating the effectiveness, safety, and quality stability of ginseng.

Influence of the Drying Method on the Volatile Component Profile of Hypericum perforatum Herb: A HS-SPME-GC/MS Study

Hypericum perforatum L. (St. John’s wort) is one of the most popular medicinal plants in the world. Due to its documented antimicrobial and antioxidant properties, it is used in the treatment of bacterial and viral infections as well as inflammations. It is also used to treat gastrointestinal diseases and mild to moderate depression. In recent years, there has been an increase in the popularity of herbal medicine. Many people collect their own herbs and dry them at home. A common choice for quick drying of fruits, vegetables and herbs at home are food dehydrator machines. There are not many publications in the scientific literature examining the quality of dried herbal material obtained in such dryers. We characterized St. John’s wort harvested in southern Poland and investigated the effect of specific drying methods on the volatile component profile. The herbal raw material was dried using three methods: indoors at room temperature, in an incubator at 37 °C and in a food dehydrator machine. Volatile components were analysed by HS-SPME GC/MS. The herb dried in a food dehydrator, compared to other drying methods, retained similar or slightly smaller amounts of the compounds from the mono- and sesquiterpenes group, aromatic monoterpenes, aromatic monoterpenoids, sesquiterpenoids, aromatic sesquiterpenes and alkanes. However, monoterpenoids and compounds coming from decomposition reactions, such as alcohols, short-chain fatty acids and esters, were noticed in larger quantities. Usage of a food dehydrator at home can be a convenient alternative to drying herbs. However, due to a different profile of volatile components depending on the drying method, the amount of biologically active substances needs to be considered. By using various methods of drying, the medical effects of herbs can be enhanced or weakened; therefore, further research in this direction should be continued.

Influence of oak chips addition on the physicochemical properties of beer

The paper discusses the influence of the oak chips addition on physicochemical properties of beer. The research material consisted of wort and beer after the fermentation, brewed in the English porter style. Medium toasted oak chips, from two varieties of an oak tree (French and American), were used. Variants without the addition of oak chips were used as control samples. The research was conducted for three periods: after 18 days, 2, and 3 months. The samples containing oak chips were characterized by higher fermentation efficiency, compared to beers without the addition of chips. Titratable acidity increased with aging time in beers containing the chips. Alcohol content decreased after 3 months in all samples. Increased amounts of oak chips and aging time, resulted in greater free amino nitrogen utilization. Prolonging the storage time of the beer with the addition of oak chips changed the profile of volatile components in the beverages.

Occurrences and changes in aroma‐associated volatile compound profiles and prominent bioactive compounds at different stages of persimmon vinegar production process

In this study, the aim was to reveal the aroma-related volatile component profiles, major bioactive compounds, and antioxidant capacities of mainly persimmon vinegar produced from persimmon fruit, as well as its juice and wine. Persimmon fruit is rich in functional compounds. However, its availability is limited due to not growing everywhere, soft texture, and it is also not preferred by consumers due to its quite astringent taste. In the study, persimmon vinegar was produced as a solution to these problems. Persimmon vinegar, stood out with high gallic, chlorogenic acid contents, and antioxidant capacity, even from apple and grape vinegars. Also, an aroma-associated volatile-compound profile of it was determined as mainly 2-butanol, acetic acid, propanol, propyl acetate, and phenethyl alcohol, and additionally chavicol, 2-butyl acetate and isovaleric -acid. Persimmon vinegar may suggest as an alternative and new product with positive health effects and different taste which can be preferred by consumers. Thus, this fruit should be used for vinegar production. Novelty impact statement Persimmon attracts attention with its rich bioactive properties and different flavor. The fermentation process causes changes in bioactive compounds and aroma components. Persimmon can be used as a novel substrate for vinegar production with bioactive compounds and distinct flavor. The aroma-related volatile component profiles, major bioactive compounds, and antioxidant capacities of persimmon vinegar, juice, and wine were firstly revealed by this study.

Effect of hot air impingement drying on drying behavior, volatile components profile, shell burst ratio, flavonoid contents, microstructure of Amomum villosum fruits

Hot air impingement drying (HAID) was employed to dry Amomum villosum (A. v.) fruit, one of the most popular traditional Chinese herbs and functional foods, under different drying temperatures, air velocities and the drying characteristics and quality were evaluated. The drying time decreased from 12 to 4 h, 10 to 8 h with the increase of temperature and velocity from 50 to 70 °C, 3 to 9 m/s, respectively. Weibull model precisely described the drying behavior. The highest total flavonoid content was obtained at 60 °C with low shell burst ratio. As for essential oil components, the relative content of monoterpenoids increased while sesquiterpenes decreased with increasing temperature. The acids and alcohols contents decreased with increase in velocity. By considering both drying time and quality, 60 °C and 6 m/s was proposed as the most favorable condition. The findings indicate HAID is a promising drying method for A. v. fruit.

Comprehensive profiling of volatile components in Taiping Houkui green tea

Taiping Houkui green tea is well-known in China for its noble aroma. Six tea strains from the Shidacha population (the predominant raw materials for Taiping Houkui green tea) and three other varieties were used to prepare green teas via the conventional techniques of Taiping Houkui green tea manufacture. Aroma evaluation confirmed that green teas produced from Shidacha strains possessed good aroma qualities. A total of ninety-six volatile compounds were identified and quantified. Hierarchical cluster analysis separated the nine green teas into three groups, and principal component analysis identified 16 volatiles (with variance importance values greater than one) that contributed to the separation. Thirty-three volatiles with odor activity values above one were identified, the highest twenty being methyl epi-jasmonate, octanal, (Z)-jasmone, β-ionone, geraniol, indole, methyl jasmonate, nonanal, decanal, linalool, benzeneacetaldehyde, phenylethyl alcohol, α-ionone, 1-octen-3-ol, cedrol, benzaldehyde, dimethyl sulfide, hexanal, 3-methylbutanal, and β-cyclocitral. All of these may be key odorants in Taiping Houkui green tea. This study suggests that the unique aroma of Taiping Houkui green tea depends both on a premium tea plant and the manufacturing process.

A study of lipolysis induced by adjuncts from edible Aspergillus sp. solid culture products on ripened semi-hard cheese.

Aspergillus sp. has been used in traditional Japanese fermented foods. Protease-containing culture products of A. oryzae have been applied as the adjunct enzyme source to enrich the flavor in ripened cheese. Although proteolysis was stimulated, the increase of free fatty acids (FFA) was recognized in some products. Since an excess amount of FFA accumulation can cause rancidity in cheese products, the assessment of lipase activity was considered to be essential for the cheese adjunct preparation. Although an equal lipase activity from the adjunct materials of A. kawachii NBRC 4308, A. luchuensis RIB 2604 and A. oryzae AHU 7139 was applied to semi-hard cheese, the FFA level was significantly higher in A. oryzae cheese than in the others. Furthermore, the profiles of volatile components were different in experimental cheeses. An in vitro study with experimental curds demonstrated that the high FFA might not depend on the lipase retainability on curds. On the contrary, the pronounced activation of the lipases occurred in A. oryzae after incubation with the curds. Moreover, incubation of the insoluble lipase that had been attached to the cells with skim milk curd extracts allowed the release of lipases from the cells into the medium with remarkable activation. A. oryzae AHU 7139 possessed a complex lipolytic system comprising extracellular and cell-binding lipases that were attributed to the increase in FFA in A. oryzae cheese. © 2022 Society of Chemical Industry.

A validated strategy to design efficient fermentation-industrial processes: agave spirit production.

An industrial process is profitable when its individual unit operations are efficient and thus, this work shows a guideline for designing efficient fermentation-industrial processes for agave distilled production based on a sequential approach of optimization, beginning in the laboratory and followed by the adjustment of the variable values using the evolutionary operation method for successful process scaling. The results at the laboratory showed that a starter inoculum containing a 5 × 106 cells/mL mixture of Kluyveromyces marxianus, Clavispora lusitaniae, and Kluyveromyces marxianus var. drosophilarum strains in a bioreactor containing agave syrup with 120g/L fermented sugar, processed at a constant temperature of 33°C and 1.0 VVM aeration for 1.6h, led to a fermented product with a 4.18% (v/v) alcohol content after 72h of processing time. The scale-up process results showed that the best operating conditions at the pilot-plant level were a temperature of 35°C and aeration at 1.0 VVM for 1.2h, which led to a fermented product with a 4.22% (v/v) total alcohol content after 72h of processing time. These represent similar performance values for both production processes, but each one worked with their specific values of process variables, which demonstrates that each level of production had its own specific values for process variables. The volatile compound analysis shows that both distilled products contained a similar profile of volatile components that provide fruity and ethereal aromatic notes pleasant to the palate. Therefore, the process design for agave spirit production at the semi-industrial level was successfully achieved.

Phytochemical characterization of some sumac (Rhus coriaria L.) genotypes from southern part of turkey

The present research aimed to study the total phenolics, total anthocyanins, total antioxidants, aroma profile, organic acids, and carbohydrate contents of 15 sumac genotypes selected from Kahramanmaras province of Turkey. Total phenols and anthocyanins were spectrophotometrically assessed. The DPPH method was used to determine the antioxidant capacity of the genotypes. Volatile component profiles were identified by HS-SPME/GC–MS while organic acids and carbohydrates were assessed by HPLC techniques. Total phenolic content of the genotypes varied from 36.38 (46SMC02) to 58.66 mg/g dw (46SMC10). Total anthocyanin content ranged from 10.87 (46SMC12) to 119.74 mg/L (46SMC05). The total antioxidant capacity was in the range of 73.37 (46SMC07) and 77.00% (46SMC06). A total of 26 volatile compounds were distinctly detected from the genotypes: 11 volatile compounds were classified as alcohols, 7 as terpenes, 6 as aldehydes and 2 as ketones. l-ascorbic acid, oxalic acid, citric acid and malic acid volumes were detected in the genotypes and their quantity ranged from 2.13 to 40.3, 1.3 to 2.9, 49.8 to 95.1 and 1360 to 2800 respectively. Sucrose quantity was found to vary between 1.41 (46SMC14) and 5.85% (46SMC01), glucose between the detection limit (46SMC01, 46SMC13 and 46SMC15) and 0.73% (46SMC09), xylose between 8.53 (46SMC14) and 30.17% (46SMC09) and fructose between an undetected value (46SMC09, 46SMC10 and 46SMC11) and 1.93% (46SMC13). The results presented here indicate that sumac fruit is a good source of nutritious compounds that may be used directly as a food source or food additives.

Volatile compounds profile of some Indonesian shallot varieties

Shallot, Allium ascolanicum L., is one of the leading horticultural commodities that are widely cultivated in Indonesia. Shallot is a commonly used seasoning for various types of dishes. This study aimed to determine the volatile compounds profile of some raw Indonesian shallot varieties. Four shallots varieties (Bima Brebes, Biru Lancor, Saptosari, and Filipin) were analyzed the volatile component profiles using Solid-Phase Microextraction (SPME)-Gas Chromatography-Mass Spectroscopy (GCMS). The GCMS analysis detected 104 types of volatile compounds in which the major volatile compounds were disulfides, sulfur-containing, thiophenes, and diverse functional groups. The most abundant volatile compound groups in the Bima Brebes variety were sulfur-containing compounds (40.61%), followed by diverse functional groups (28.43%) and disulfide (17.51%). In the Biru Lancor variety, the major volatile compounds were disulfide (44.68%), followed by sulfur-containing (30.90%) and thiophenes (8.80%). The most abundant volatile groups in the Saptosari variety were sulfur-containing (57.06%), followed by disulfide (22.68%) and thiophenes (9.19%). In the Filipin variety, the major volatile compound groups were disulfide (53.80%), followed by thiophenes (15.70%), and sulfur-containing (10.55%). The most abundant volatile compounds in all shallots volatiles were dipropyl disulfide, 1-methylethyl propyl disulfide, (E)-1-(prop-1-en-1-yl)-2-propyldisulfane, and propyl mercaptan.

Deep Ocean Water Concentrate Changes Physicochemical Characteristics, the Profile of Volatile Components and Consumer Acceptance for Taiwanese Rice Shochu.

To study the effects of deep-ocean water concentrate (DOWC) on sake quality, Taichung No. 10 indica rice (Oryza sativa subsp. indica) and Tainan No. 11 japonica rice (O. sativa subsp. japonica) were used as raw materials, and basic physicochemical property parameters in shochu were analyzed differentially. Sake fermentation mash analysis results revealed that DOWC addition did not significantly affect the basic physicochemical properties during sake brewing, but it significantly reduced citric acid and malic acid contents in Taichung No. 10 indica rice sake sample by 52–66% and 73–93%, respectively. DOWC addition significantly increased citric acid content in Tainan No. 11 japonica rice sake sample by 32–202%. Rice shochu analysis results revealed that DOWC addition significantly increased isoamyl acetate, ethyl hexanoate, and ethyl octanoate contents in shochu made from japonica rice and indica rice, respectively. The results indicate that rice variety directly affects the types of volatile compounds in rice shochu. Principal component analysis and sensory evaluation results revealed that DOWC addition affected the composition of volatile compounds in the two types of rice shochu and resulted in differences in flavor evaluation. DOWC addition affects yeast metabolites and directly changes the volatile compound composition and flavor of rice shochu.