Different Polar Metabolites and Protein Profiles between High- and Low-Quality Japanese Ginjo Sake

Spatial Distribution and Characteristics of Protein Content and Composition in Japonica Rice Grains: Implications for Sake Quality

The quantity and composition of rice proteins play a crucial role in determining taste quality of sake, Japanese rice wine. However, the spatial distribution of proteins within rice grains, especially in endosperm tissue, and the differences between rice varieties remain unclear. Here, we analyzed the crude protein contents and composition ratios of table (Nipponbare and Koshihikari) and genuine sake rice varieties (Yamadanishiki, Gohyakumangoku, Dewasansan, Dewanosato, and Yumenokaori) to elucidate their spatial distribution within the Japonica rice grain endosperm. Seven sake rice varieties were polished over five harvest years using a brewer's rice-polishing machine. We obtained fractions at 90-70% (the outermost endosperm fraction), 70-50%, 50-30%, and 30-0% (the central region of the endosperm fraction). Yamadanishiki and Dewanosato exhibited considerably lower crude protein contents than the other cultivars. After applying SDS-PAGE, the protein composition, comprising glutelin/total protein (G/TP), prolamin/TP (P/TP), and G/P ratios of these fractions was determined. In white rice (at a 90% rice-polishing ratio), the average ratio of the major protein composition was G/TP 41%, P/TP 21%, and G/P ratios of 1.97. Gohyakumangoku and Yamadanishiki had higher G/TP ratio, while Dewanosato had a lower value. Despite having lower crude protein contents, Yamadanishiki and Dewanosato exhibited significantly varying G/TP ratios. The G/TP ratio markedly varied among rice varieties, particularly in the rice grains' central region. The 50-30% fraction had the highest P/TP ratio among all tested rice varieties, suggesting spatial differences in P/TP within rice grains. Koshihikari had the lowest P/TP ratio. In addition, the 50-30% fraction had the lowest G/P ratio among all tested rice varieties, with Gohyakumangoku having the highest G/P ratio. Dewanosato had the lowest G/P value, and this value significantly differed from that of Yamadanishiki in the 30-0% fraction. We found substantial differences in protein composition within distinct spatial regions of rice grains, and larger differences among rice varieties were observed in the rice grain's central region.

Metagenomics-based insights into the microbial community profiling and flavor development potentiality of baijiu Daqu and huangjiu wheat Qu

Daqu and wheat Qu are saccharification and fermenting agents in Chinese huangjiu and baijiu production. This study aimed to investigate the difference between Daqu and wheat Qu in physicochemical indices, microbial communities, functional genes, and the metabolic network of key microbes responsible for flavor synthesis by whole-metagenome sequencing and metabolite analysis. Herein, physicochemical indices indicated that compared with wheat Qu, Daqu exhibited higher protease and cellulase activity and acidity, and lower glucoamylase and amylase enzyme activity. Metagenomic sequencing reveals that although Daqu and wheat Qu community composition have significant differences at species level, they have similar functional genes. Daqu were enriched in Pediococcus pentosaceus, Weissella paramesenteroides, Rasamsonia emersonii and Byssochlamys spectabilis (22.48% of the total abundance), while wheat Qu harbored greater abundances of Saccharopolyspora (54.78%, Saccharopolyspora rectivirgula, Saccharopolyspora shandongensis, Saccharopolyspora hirsuta, Saccharopolyspora spinose, and Saccharopolyspora erythraea). From a functional perspective, the important functions of Daqu and wheat Qu are both amino acid metabolism and carbohydrate metabolism. Meanwhile, a combined analysis among microbiota, functional genes, and dominant flavors indicated S. shandongensis, S. rectivirgula, and S. spinose might be the main contributor to the synthesis of flavor compounds in wheat Qu, while R. emersonii, W. paramesenteroides, Leuconostoc citreum, Leuconostoc mesenteroides, Weissella cibaria and P. pentosaceus may make the greatest contribution to flavor compounds synthesis in Daqu. This study reveals the microbial and functional dissimilarities of Daqu and wheat Qu, and helps elucidating different metabolic roles of microbes during flavor formation.

Pairing of white wine made with shade-grown grapes and Japanese cuisine

This study investigated the effect of pairing of wine vinified from shade-grown grapes before onset of ripening on the palatability of sashimi, a typical Japanese cuisine. GC-MS analyses of volatile chemicals revealed that shading reduced phenolic compounds and terpenoids, and added fatty acid ethyl esters which are also known to contribute to the flavor of Japanese sake. When the pairing of sashimi with wine was evaluated by individuals who regularly drink Japanese sake during meals, shade wine was more highly rated than wine made from normally-grown grapes.

Gas Chromatography-Mass Spectrometry-Based Metabolomic Analysis of Wagyu and Holstein Beef

Japanese Black cattle (Wagyu) beef is characterized by high intramuscular fat content and has a characteristic sweet taste. However, the chemical components for characterizing the sweet taste of Wagyu beef have been unclear. In this experiment, we conducted a metabolomic analysis of the longissimus muscle (sirloin) in Wagyu and Holstein cattle to determine the key components associated with beef taste using gas chromatography–mass spectrometry (GC-MS). Holstein sirloin beef was characterized by the abundance of components such as glutamine, ribose-5-phosphate, uric acid, inosine monophosphate, 5-oxoproline, and glycine. In contrast, Wagyu sirloin beef was characterized by the abundance of sugar components (maltose and xylitol). Dietary fat is known to increase the intensity of sweet taste. These results suggest that the sweet taste of Wagyu beef is due to the synergetic effects of higher sugar components and intramuscular fat.

Glutelin subtype-dependent protein localization in rice grain evidenced by immunodetection analyses

GluA and GluB-4/5 glutelin subfamilies are mainly localized to outer region of the endosperm, particularly in its ventral side, in rice grain, but GluC is localized to throughout the endosperm. The major seed storage protein in rice (Oryza sativa) is glutelin, which forms a vacuole-derived protein body type-II. Glutelins are encoded by multiple genes, and generally comprise four protein subfamilies, namely, GluA, GluB, GluC, and GluD: however, the localization pattern of glutelin in rice grains remains obscure. In this study, we investigated the localization pattern of five subtypes of the glutelin protein in rice grains using glutelin-subtype specific antibodies. Immunoblot analysis against sequentially polished rice flour fractions from three crop years and seven japonica rice varieties revealed that GluA was strongly localized in the outer region of the endosperm, including the subaleurone layer, whereas GluC was distributed throughout the endosperm. Among the glutelin subtypes, GluA was mostly found in the outer region of the rice grain, followed by GluB-4/5, GluB-1, GluD, and GluC. Immunofluorescence labeling microscopy analysis using immature rice seeds clearly revealed that the localization pattern of GluC and GluD was completely different from that of GluA and GluB. Expression levels of all glutelins, particularly GluA, GluB-1, and GluB-4/5, were stronger on the ventral than dorsal side in rice grains. These results provide strong and consistent evidence that glutelins localize to the rice grain in a subfamily-dependent manner.

Fathoming Aspergillus oryzae metabolomes in formulated growth matrices

The stochasticity of Aspergillus oryzae (Trivially: the koji mold) pan-metabolomes commensurate with its ubiquitously distributed landscapes, i.e. growth matrices have been seemed uncharted since its food fermentative systems are mostly being investigated. In this review, we explicitly have discussed the likely tendencies of A. oryzae metabolomes pertaining to its growth milieu formulated with substrate matrices of varying nature, composition, texture, and associated physicochemical parameters. We envisaged typical food matrices, namely, meju, koji, and moromi as the semi-natural cultivation models toward delineating the metabolomic patterns of the koji mold, which synergistically influences the organoleptic and functional properties of the end products. Further, we highlighted how tailored conditions in sub-natural growth matrices, i.e. synthetic cultivation media blends, inducers, and growth surfaces, may influence A. oryzae metabolomes and targeted phenotypes. In general, the sequential or synchronous growth of A. oryzae on formulated matrices results in a number of metabolic tradeoffs with its immediate microenvironment influencing its adaptive and regulatory metabolomes. In broader context, evaluating the metabolic plasticity of A. oryzae relative to the tractable variables in formulated growth matrices might help approximate its growth and metabolism in the more complex natural matrices and environs. These approaches may considerably help in the design and manipulation of hybrid cultivation systems towards the efficient harnessing of commercial molds.

Agmatine Production by Aspergillus oryzae Is Elevated by Low pH during Solid-State Cultivation

Sake (rice wine) produced by multiple parallel fermentation (MPF) involving Aspergillus oryzae (strain RW) and Saccharomyces cerevisiae under solid-state cultivation conditions contained 3.5 mM agmatine, while that produced from enzymatically saccharified rice syrup by S. cerevisiae contained <0.01 mM agmatine. Agmatine was also produced in ethanol-free rice syrup prepared with A. oryzae under solid-state cultivation (3.1 mM) but not under submerged cultivation, demonstrating that A. oryzae in solid-state culture produces agmatine. The effect of cultivation conditions on agmatine production was examined. Agmatine production was boosted at 30°C and reached the highest level (6.3 mM) at pH 5.3. The addition of l-lactic, succinic, and citric acids reduced the initial culture pHs to 3.0, 3.5, and 3.2, respectively, resulting in a further increase in agmatine accumulation (8.2, 8.7, and 8.3 mM, respectively). Homogenate from a solid-state culture exhibited a maximum l-arginine decarboxylase (ADC) activity (74 pmol · min^-1 · μg^-1) at pH 3.0 at 30°C; homogenate from a submerged culture exhibited an extremely low activity (<0.3 pmol · min^-1 · μg^-1) under all conditions tested. These observations indicated that efficient agmatine production in ethanol-free rice syrup is achieved by an unidentified low-pH-dependent ADC induced during solid-state cultivation of A. oryzae, even though A. oryzae lacks ADC orthologs and instead possesses four ornithine decarboxylases (ODC1 to ODC4). Recombinant ODC1 and ODC2 exhibited no ADC activity at acidic pH (pH < 4.0), suggesting that other decarboxylases or an unidentified ADC is involved in agmatine production.IMPORTANCE It has been speculated that, in general, fungi do not synthesize agmatine from l-arginine because they do not possess genes encoding arginine decarboxylase. Numerous preclinical studies have shown that agmatine exerts pleiotropic effects on various molecular targets, leading to an improved quality of life. In the present study, we first demonstrated that l-arginine was a feasible substrate for agmatine production by the fungus Aspergillus oryzae RW. We observed that the productivity of agmatine by A. oryzae RW was elevated at low pH only during solid-state cultivation. A. oryzae is utilized in the production of various Asian fermented foods. The saccharification conditions optimized in the current study could be employed not only in the production of an agmatine-containing ethanol-free rice syrup but also in the production of many types of fermented foods, such as soy sauce (shoyu), rice vinegar, etc., as well as for use as novel therapeutic agents and nutraceuticals.

Characterizing amino-acid biosignatures amongst individuals with schizophrenia: a case-control study

Amino acids and derivatives participate in the biosynthesis and downstream effects of numerous neurotransmitters. Variations in specific amino acids have been implicated in the pathophysiology of schizophrenia. Herein, we sought to compare levels of amino acids and derivatives between subjects with schizophrenia and healthy controls (HC). Two hundred and eight subjects with Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition criteria (DSM-IV)-defined schizophrenia and 175 age- and sex-matched HC were enrolled. The levels of twenty-five amino acids and seven related derivatives were measured in plasma samples using hydrophilic interaction liquid chromatography (HILIC) liquid chromatography-tandem mass spectrometry (LC-MS). After controlling for age, sex and body mass index (BMI), four amino acids and derivatives (i.e., cysteine, GABA, glutamine and sarcosine) were observed to be higher in the schizophrenia group when compared with HC; seven amino acids and derivatives were lower in the schizophrenia group (i.e., arginine, L-ornithine, threonine, taurine, tryptophan, methylcysteine, and kynurenine). Statistically significant differences in plasma amino-acid profiles between subjects with first-episode vs. recurrent schizophrenia for aspartate and glutamine were also demonstrated using generalized linear models controlling for age, sex, and BMI. The differences in amino acids and derivatives among individuals with schizophrenia when compared to HC may represent underlying pathophysiology, including but not limited to dysfunctional proteinogenic processes, alterations in excitatory and inhibitory neurotransmission, changes in ammonia metabolism and the urea cycle. Taken together, amino-acid profiling may provide a novel stratification approach among individuals with schizophrenia.

Assessment of Anticancer Drug Effects on Pancreatic Cancer Cells under Glucose-Depleted Conditions Using Intracellular and Extracellular Amino Acid Metabolomics

Previously, we developed a method to evaluate states of cells treated with anticancer drugs via the comprehensive analysis of amino acids, termed amino acid metabolomics. In the present study, we evaluated the effects of the anticancer drugs, gemcitabine hydrochloride and pyrvinium pamoate, on the proliferation of a pancreatic cancer cell line (PANC-1) under hypoglycemic conditions using amino acid metabolomics. Intracellular and extracellular amino acid profiles of PANC-1 were determined by hydrophilic interaction chromatography-tandem mass spectrometry with simple pretreatment. Changes to the drugs' anticancer effects resulting from glucose starvation conditions were presented in score plots obtained from principal component analyses. In particular, the analysis of intracellular amino acids was found to be the superior approach because the results allowed a clearer assessment of the cell state. Further, orthogonal partial least squares discriminant analysis was performed to search for amino acid candidates that discriminate with anticancer drug-treated PANC-1 cells. We identified several amino acids that might be able to distinguish the drug-treated group from the control group. These results might provide a better understanding of the mechanisms underlying cell responses such as drug resistance or austerity. The present study is the first to evaluate the efficacy of anticancer drugs under glucose starvation based on the analysis of the variation of extracellular and intracellular amino acid profiles in vitro.

Metabolite profiling of the fermentation process of "yamahai-ginjo-shikomi" Japanese sake

Sake is a traditional Japanese alcoholic beverage prepared by multiple parallel fermentation of rice. The fermentation process of "yamahai-ginjo-shikomi" sake is mainly performed by three microbes, Aspergillus oryzae, Saccharomyces cerevisiae, and Lactobacilli; the levels of various metabolites fluctuate during the fermentation of sake. For evaluation of the fermentation process, we monitored the concentration of moderate-sized molecules (m/z: 200-1000) dynamically changed during the fermentation process of "yamahai-ginjo-shikomi" Japanese sake. This analysis revealed that six compounds were the main factors with characteristic differences in the fermentation process. Among the six compounds, four were leucine- or isoleucine-containing peptides and the remaining two were predicted to be small molecules. Quantification of these compounds revealed that their quantities changed during the month of fermentation process. Our metabolomic approach revealed the dynamic changes observed in moderate-sized molecules during the fermentation process of sake, and the factors found in this analysis will be candidate molecules that indicate the progress of "yamahai-ginjo-shikomi" sake fermentation.

Recent advances in amino acid analysis by capillary electromigration methods: June 2015-May 2017

In the tenth edition of this article focused on recent advances in amino acid analysis using capillary electrophoresis, we describe the most important research articles published on this topic during the period from June 2015 to May 2017. This article follows the format of the previous articles published in Electrophoresis. The new developments in amino acid analysis with CE mainly describe improvements in CE associated with mass spectrometry. Focusing on applications, we mostly describe clinical works, although metabolomics studies are also very important. Finally, works focusing on amino acids in food and agricultural applications are also described.

Milk kefir: nutritional, microbiological and health benefits

Kefir is fermented milk produced from grains that comprise a specific and complex mixture of bacteria and yeasts that live in a symbiotic association. The nutritional composition of kefir varies according to the milk composition, the microbiological composition of the grains used, the time/temperature of fermentation and storage conditions. Kefir originates from the Caucasus and Tibet. Recently, kefir has raised interest in the scientific community due to its numerous beneficial effects on health. Currently, several scientific studies have supported the health benefits of kefir, as reported historically as a probiotic drink with great potential in health promotion, as well as being a safe and inexpensive food, easily produced at home. Regular consumption of kefir has been associated with improved digestion and tolerance to lactose, antibacterial effect, hypocholesterolaemic effect, control of plasma glucose, anti-hypertensive effect, anti-inflammatory effect, antioxidant activity, anti-carcinogenic activity, anti-allergenic activity and healing effects. A large proportion of the studies that support these findings were conducted in vitro or in animal models. However, there is a need for systematic clinical trials to better understand the effects of regular use of kefir as part of a diet, and for their effect on preventing diseases. Thus, the present review focuses on the nutritional and microbiological composition of kefir and presents relevant findings associated with the beneficial effects of kefir on human and animal health.