Biotransformation of hop-derived monoterpene alcohols by lager yeast and their contribution to the flavor of hopped beer.

It is well-known that various beers contain many flavor compounds derived from barley malts, hops, yeast fermentation, and other raw materials. Among these flavor compounds, terpenoids are mainly derived from hops. Linalool, one of the monoterpene alcohols, has been found in various beers and been regarded as an important factor for a hop-derived beer flavor. We focus on contributions of other monoterpene alcohols (geraniol, beta-citronellol, nerol, and alpha-terpineol) to hopped beer flavor. Several researchers have reported that monoterpene alcohols are biotransformed by yeast and that geraniol is mainly transformed to beta-citronellol during the first 2-4 days in model fermentation. In this study, we investigated the biotransformation of monoterpene alcohols during fermentation of hopped beer by using various hop cultivars. As a result, geraniol drastically decreased during the first 3 days. beta-Citronellol was almost absent in wort and gently increased during the total fermentation period. The concentrations of geraniol and beta-citronellol in finished beer increased, depending on the initial concentration of geraniol in the wort. The continuous increase of beta-citronellol did not correspond to the fast decrease of geraniol. This increase of beta-citronellol might be partly explained by an occurrence of glycosidically bound flavor precursor and a glucoside hydrolase activity secreted from lager yeast. In addition, we examined flavor characteristics of monoterpene alcohols and found that there was an additive effect among linalool, geraniol, and beta-citronellol and that only 5 microg/L of geraniol and beta-citronellol were enough for this effect. Therefore, it is suggested that not only linalool but also geraniol and beta-citronellol might contribute to hopped beer flavor at lower levels, at which OAVs of these compounds become below 1.0.

Oral administration of heat-killed Lactobacillus brevis SBC8803 ameliorates alcoholic liver disease in ethanol-containing diet-fed C57BL/6N mice.

We examined the effect of heat-killed Lactobacillus brevis (L. brevis) SBC8803 on the development of alcoholic liver disease using ethanol-containing diet-fed mice. Heat-killed L. brevis was orally administered at a dose of 100 or 500 mg/kg once a day for 35 days. Alcoholic liver injury was examined by measuring the activity of alanine aminotransferase (ALT) and aspartate aminotransferase (AST) in a serum, and the alcoholic fatty liver was assessed from the content of triglyceride (TG) and total cholesterol in the liver. Quantitative RT-PCR was used to examine mRNA expression of tumor necrosis factor (TNF)-alpha, sterol regulatory element-binding protein (SREBP)-1, SREBP-2, and peroxisome proliferator-activated receptor alpha (PPARalpha) in the liver, as well as E-cadherin, Zonula occludens 1 (ZO-1), and heat shock protein (Hsp) 25 in the small intestine. Oral administration of L. brevis significantly inhibited an increase in the level of serum ALT and AST, as well as the content of TG and total cholesterol in the liver caused by ethanol intake. L. brevis supplementation suppressed the overexpression of TNF-alpha, SREBP-1, and SREBP-2 mRNA in the liver induced by ethanol intake and up-regulated the expression of Hsp25 mRNA in the small intestine. These results suggest that L. brevis ameliorated the ethanol-induced liver injury and the fatty liver by suppressing the up-regulation of TNF-alpha and SREBPs in the liver. We speculate that the inhibition of TNF-alpha and SREBPs up-regulation by L. brevis is due to the inhibition of gut-derived endotoxin migration into the liver through the enhancement of intestinal barrier function by the induction of cytoprotective Hsps.

Oral administration of heat-killed Lactobacillus brevis SBC8803 ameliorates the development of dermatitis and inhibits immunoglobulin E production in atopic dermatitis model NC/Nga mice.

We have previously shown that the oral administration of heat-killed Lactobacillus brevis (L. brevis) SBC8803 strain inhibits IgE production in ovalbumin (OVA)-sensitized BALB/c mice through improvement of the type-1 helper T (Th1)/Th2 balance toward Th1 dominance. Atopic dermatitis is one of the most common skin diseases and is frequently associated with elevated immunoglobulin E (IgE) antibodies against many kinds of allergens. In this study, we investigated the inhibitory effect of oral administration of L. brevis SBC8803 on the development of dermatitis and IgE elevation using the NC/Nga atopic dermatitis model mice. Male 8-week-old NC/Nga mice were sensitized by the topical application of picryl chloride to foot pads and shaved abdomen. These mice were boosted with picryl chloride by topical application onto the ears once a week for 9 weeks. The mice (n=10 per group) were fed a diet containing 0%, 0.05% or 0.5% of heat-killed L. brevis SBC8803 from 2 weeks before the first sensitization to the end of the study. Total IgE concentration in serum, clinical score, and ear thickness were periodically examined throughout the study. Finally, cytokine (interleukin (IL)-4, IL-5, IL-6, IL-10, IL-12, IFN-gamma and transforming growth factor (TGF)-beta) productions from splenocytes and Peyer's patch (PP) cells of mice were measured. Oral administration of L. brevis SBC8803 significantly inhibited IgE production and ear swelling, and suppressed the development of dermatitis in a dose-dependent manner. Immunosuppressive cytokines such as IL-10 and TGF-beta production from PP cells significantly increased in the 0.5% group compared to the control group although Th1-type and Th2-type cytokines production was not affected.

Oral administration of a hop water extract ameliorates the development of dermatitis induced by the periodical topical application of a mite antigen in atopic dermatitis model NC/Nga mice.

We investigated the inhibitory effect of an oral administration of a hop water extract (HWE) on the development of dermatitis by using NC/Nga atopic dermatitis model mice. The induction of allergic dermatitis was conducted by tape-stripping and topical application of a mite antigen (Dermatophagoides farinae) on to the ear once a week for 10 weeks. HWE was orally administered at a dose of 100 or 500 mg/kg. The total immunoglobulin E (IgE) concentration in serum and the ear thickness were periodically examined. Finally, the antigen-specific IgE level in the serum and the production of interleukin (IL)-4, IL-12 and interferon (IFN)-gamma from splenocytes and cervical lymph node cells were measured. The oral administration of HWE significantly inhibited the increase of total IgE production and ear swelling throughout the experimental period. The production of IL-12 was significantly lower in the HWE administered group than in the control group. The results suggest that the intake of HWE may be effective in preventing and alleviating the development of atopic dermatitis-like skin disease.

Effect of high beta-glucan barley on serum cholesterol concentrations and visceral fat area in Japanese men--a randomized, double-blinded, placebo-controlled trial.

This study investigated whether the consumption of a diet in which high-beta-glucan barley replaced rice would reduce the visceral fat area as well as the serum low-density lipoprotein cholesterol (LDL-C) and total cholesterol (TC) in hypercholesterolemic Japanese men. A randomized, double-blinded, placebo-controlled intervention study was conducted in 44 hypercholesterolemic Japanese men with a body mass index (BMI) >22 kg/m2. The subjects were randomly assigned to groups consuming either rice (placebo group) or a mixture of rice and pearl barley with a high beta-glucan content (test group, 7.0 g beta-glucan per day) for 12 weeks. Blood samples were taken, and CT scan obtained before the trial and every four weeks during the trial. The pearl barley intake significantly reduced serum concentrations of LDL-C (P = 0.041) and TC (P = 0.037) during the trial. Significant differences between the test and placebo groups were found for the visceral fat (P = 0.039), BMI (P = 0.015), and waist circumference (P = 0.011) at the end point. The consumption of pearl barley with a high beta-glucan content reduces not only LDL-C but also visceral fat area.

Effect of oral administration of heat-killed Lactobacillus brevis SBC8803 on total and ovalbumin-specific immunoglobulin E production through the improvement of Th1/Th2 balance.

We examined the effect of 59 strains of heat-killed Lactobacillus brevis on interleukin (IL)-12 and interferon (IFN)-gamma production from mouse Peyer's patch (PP) cells. L. brevis has a great variety of strains that induce the production of these cytokines. Some L. brevis strains, which were selected for their ability to induce a strong Th1 immune response, inhibited both total immunoglobulin E (IgE) and antigen specific IgE production, and improved the Th1/Th2 balance by enhancing IL-12 and IFN-gamma and inhibiting IL-4 production from ovalbumin (OVA)-sensitized mouse splenocytes. Based on the results of this screening, we selected L. brevis SBC8803 as a potent inhibitor of IgE production, and investigated the effect of oral administration of heat-killed SBC8803 on IgE production in OVA-sensitized mice. OVA-sensitized mice were fed SBC8803 0% (control), 0.05%, or 0.5% added diet for 4 weeks during the period of the experiment. Total and OVA-specific IgE in the serum of mice, which were fed the 0.5% added diet, was significantly lower than that of the control diet fed mice. The IFN-gamma/IL-4 value, which represents the Th1/Th2 balance, from the 0.5% added diet fed mice splenocytes was also significantly higher than that of the control diet fed mouse splenocytes. Histamine release from OVA-sensitized mice into sera that were induced by the intraperitoneal antigen challenge decreased following the oral administration of SBC8803. The inhibition of IgE production and histamine secretion by the oral administration of heat-killed SBC8803 was probably due to the improvement of the Th1/Th2 balance toward Th1 dominance.

Clinical effects of a hop water extract on Japanese cedar pollinosis during the pollen season: a double-blind, placebo-controlled trial.

The clinical effects of an oral administration of a hop water extract (HWE) on the improvement of Japanese cedar pollinosis (JCPsis) symptoms were investigated. In a double-blind, placebo-controlled trial, 39 subjects took a drink containing either 100 mg of HWE or a placebo for 12 weeks during the pollen season. Nasal symptoms (sneezing attacks, nasal discharge, and nasal obstruction) were assessed from the subjects' diaries. A clinical examination and blood sampling were carried out before and 4, 8 and 12 weeks after the initiation of treatment. As a result, a significant difference was observed in the symptom score and in the symptom-medication score 10 weeks after the intervention in comparison with the placebo group. Improvements were observed in nasal swelling, nasal color, amount of nasal discharge, and characteristics of nasal discharge in the intervention group 12 weeks after the treatment. No significant eosinophil infiltration into the nasal discharge was apparent in the intervention group throughout the study period, although it was observed in the placebo group. These findings indicate that an oral administration of HWE may be effective in alleviating the allergic symptoms related to JCPsis.

Effects of a hop water extract on the compound 48/80-stimulated vascular permeability in ICR mice and histamine release from OVA-sensitized BALB/c mice.

The antiallergic properties of a hop water extract (HWE) were studied by evaluating the Evans blue leakage from ICR mice caused by compound 48/80 stimulation, and the histamine release from ovalbumin (OVA)-sensitized BALB/c mice. An oral administration of HWE significantly inhibited the vascular permeability and histamine release. HWE itself did not have any influence on the total and antigen-specific immunoglobulin E (IgE) production in OVA-sensitized mice. These results indicate that HWE exerted an antiallergic effect by inhibiting the release of chemical mediators from mast cells and basophiles.

Flavonoid glycosides extracted from hop (Humulus lupulus L.) as inhibitors of chemical mediator release from human basophilic KU812 cells.

The antiallergic properties of hop water extract (HWE) were studied by evaluating histamine release from human basophilic KU812 cells induced by calcium ionophore A23187. HWE significantly inhibited histamine release, but boiling water extract and chloroform-methanol extract did not show any inhibitory effect on it. A 50% methanol-eluted fraction separated from HWE by XAD-4 column chromatography (MFH) had a strong inhibitory effect as compared with HWE. Quercetin glycosides and kaempherol glycosides were identified in MFH, of which quercetin glycosides contributed to the inhibition of histamine release. Most quercetin in HWE existed in glycoside form and its quercetin content, obtained by acid hydrolysis, was about 200 mug/g. HWE and MFH significantly inhibited protein kinase C, which plays a pivotal role in the degranulation of chemical mediators. These results indicate that HWE can inhibit type-I allergic reactions.

Effects of hop extracts on nasal rubbing and sneezing in BALB/c mice.

The effects of hop extracts (Humulus lupulus L.) on histamine release from rat peritoneal mast cells and human basophilic KU812 cells were studied. Hop water extract (HWE) and XAD-4 50% methanol fraction of HWE (MFH) inhibited histamine release from rat mast cells induced by compound 48/80 at concentrations of 100 and 10 mug/ml, respectively. Almost the same findings were observed with A23187-induced histamine release from KU812 cells. Next, we studied the effects of hop extracts on antigen-induced nasal rubbing and sneezing in sensitized BALB/c mice. HWE caused a significant inhibition of nasal rubbing and sneezing at a dose of 500 mg/kg. MFH also inhibited nasal rubbing and sneezing dose-dependently. A significant difference was observed from 100 mg/kg in nasal rubbing and 200 mg/kg in sneezing. The effects of both extracts became clear after repeated administration. HWE and MFH significantly inhibited both nasal rubbing and sneezing, respectively, after consecutive treatment for 15 d at smaller doses compared with single administration. This finding indicates that the active component of hop is included in MFH, which was absorbed to Amberlite XAD-4 and eluted with 50% methanol. These results clearly demonstrated that hop extracts may be effective in the relief of symptoms of allergic rhinitis.

Characterization of factors that transform linoleic acid into di- and trihydroxyoctadecenoic acids in mash.

The qualities of beer are deteriorated by the presence of either di- or trihydroxyoctadecenoic acids, which reduce the beer 'head' and produce an astringent flavor. In this study we found that native extracts of malt mash transformed linoleic acid into di- and trihydroxyoctadecenoic acids, but this transforming activity and lipoxygenase activity were inactivated by heating the mash at 70 degrees C for 30 min. Recombinant barley lipoxygenase 1 was not able to transform linoleic acid into di- and trihydroxyoctadecenoic acids. The transforming activity of mash extract heated at 70 degrees C for 30 min could be restored by the addition of recombinant barley lipoxygenase 1; in contrast, the activity of boiled mash extract was not substantially restored by the recombinant enzyme. These results indicate that di- and trihydroxyoctadecenoic acids are generated from linoleic acid by both lipoxygenase and a heat-stable enzymatic factor present in the mash.

Analysis of an inactivated Lg-FLO1 gene present in bottom-fermenting yeast.

During the course of investigating a flocculation-related gene of a bottom-fermenting yeast, we identified a new Lg-FLO1 homologue which contains the N-terminal domain of the Lg-FLO1 gene. The results of the partial DNA sequence analysis of the amplified product obtained by inverse-PCR suggested that the homologue contains a sequence present in the YIL169c (chr. IX of Saccharomyces cerevisiae). Southern blot analyses using the VTH1, HXT12, SDL1 and UBP7 genes as probes for chr. IX strongly indicated that an approximately 20-kb region from the YIL169c ORF to the left telomere in chr. IX translocated to the Lg-FLO1 ORF region in chr. VIII of bottom-fermenting yeast. This translocation might convert a flocculent cell to a non-flocculent one.

Breeding of brewer's yeast by hybridization between a top-fermenting yeast Saccharomyces cerevisiae and a cryophilic yeast Saccharomyces bayanus.

To improve the fermentability of a top-fermenting yeast at low-temperature, we performed hybridization trials between four top-fermenting Saccharomyces cerevisiae strains and a cryophilic yeast Saccharomyces bayanus YM84 with good fermentability at low-temperature. The hybrids selected using 5-bromo-4-chloro-3-indolyl-alpha-D-galactopyranoside were checked with pulsed-field gel electrophoresis and their brewing performance at the low-temperature of 10.5 degrees C was observed using small-scale (2 l) fermentation trials.