This paper reports on the influence of molecular weight and concentration of barley ␤-glucans on the rheological properties of wort and beer. Environmental conditions such as pH, maltose level in wort, ethanol content of beer, shearing and shearing temperature were also examined for their effects on wort and beer viscosities. In the range of 50-1000 mg/L, ␤-glucans increased solution viscosity linearly with both molecular weights (MW) of 31, 137, 250, 327, and 443 kDa and concentration. The influence of MW on the intrinsic viscosity of ␤-glucans followed the Mark-Houwink relationship. Shearing wort and beer at approximately 13,000 s -1 for 35 s was found to increase the wort viscosity but reduce beer viscosity. Shearing wort at 20°C influenced ␤-glucan viscosity more than shearing at 48°C and 76°C whereas the shearing temperature (0, 5 and 10°C) did not effect the viscosity of beer. At lower pHs, shearing was found to reduce the viscosity caused by ␤-glucans in wort but had no effect in beer. Higher concentrations of maltose in wort and ethanol in beer also increased the viscosity of ␤-glucan polymers. It was found that ␤-glucans had higher intrinsic viscosities in beer than in wort (5°C), and lower critical overlap concentrations (C*) in beer than in wort.

Background: Withania somnifera (WS), also known as Ashwagandha, is commonly used in Ayurveda and other traditional medicine systems. WS has seen an increase in public use worldwide due to its reputation as an adaptogen. This popularity has elicited increased scientific study of its biological effects, including a potential application for neuropsychiatric and neurodegenerative disorders. Objective: This review aims to provide a comprehensive summary of preclinical and clinical studies examining the neuropsychiatric effects of WS, specifically its application in stress, anxiety, depression, and insomnia. Methods: Reports of human trials and animal studies of WS were collected primarily from the PubMed, Scopus, and Google Scholar databases. Results: WS root and leaf extracts exhibited noteworthy anti-stress and anti-anxiety activity in animal and human studies. WS also improved symptoms of depression and insomnia, though fewer studies investigated these applications. WS may alleviate these conditions predominantly through modulation of the hypothalamic-pituitary-adrenal and sympathetic-adrenal medullary axes, as well as through GABAergic and serotonergic pathways. While some studies link specific withanolide components to its neuropsychiatric benefits, there is evidence for the presence of additional yet unidentified active compounds in WS. Conclusion: While benefits were seen in the reviewed studies, significant variability in the WS extracts examined prevents a consensus on the optimum WS preparation or dosage from treating neuropsychiatric conditions. WS generally appears safe for human use; however, it will be important to investigate potential herb-drug interactions involving WS if used alongside pharmaceutical interventions. Further elucidation of active compounds of WS is also needed.

Centella asiatica is reputed in Eastern medicine to improve cognitive function in humans. Preclinical studies have demonstrated that aqueous extracts of C. asiatica improve cognition in mouse models of aging and Alzheimer’s disease (AD) through the modulation of mitochondrial biogenesis and nuclear factor-erythroid-2-related factor 2 (Nrf2)-dependent antioxidant response genes. This randomized, double-blind, crossover Phase I trial explored the oral bioavailability and pharmacokinetics of key compounds from two doses (2 g and 4 g) of a standardized C. asiatica aqueous extract product (CAP), over 10 h, in four mildly demented older adults on cholinesterase inhibitor therapy. The analysis focused on triterpenes (TTs) and caffeoylquinic acids (CQAs), which are known to contribute to C. asiatica’s neurological activity. The acute safety of CAP and the effects on NRF2 gene expression in peripheral blood mononuclear cells were evaluated. Single administration of 2 g or 4 g of CAP was safe and well-tolerated. The TT aglycones, asiatic acid and madecassic acid, were identified in plasma and urine, while the parent glycosides, asiaticoside and madecassoside, although abundant in CAP, were absent in plasma and had limited renal excretion. Similarly, mono- and di-CQAs showed delayed absorption and limited presence in plasma or urine, while the putative metabolites of these compounds showed detectable plasma pharmacokinetic profiles and urinary excretion. CAP elicited a temporal change in NRF2 gene expression, mirroring the TT aglycone’s pharmacokinetic curve in a paradoxical dose-dependent manner. The oral bioavailability of active compounds or their metabolites, NRF2 target engagement, and the acute safety and tolerability of CAP support the validity of using CAP in future clinical studies.

Centella asiatica is an herb used in Ayurvedic and traditional Chinese medicine for its beneficial effects on brain health and cognition. Our group has previously shown that a water extract of Centella asiatica (CAW) elicits cognitive-enhancing effects in animal models of aging and Alzheimer’s disease, including a dose-related effect of CAW on memory in the 5xFAD mouse model of ß-amyloid accumulation. Here, we endeavor to elucidate the mechanisms underlying the effects of CAW in the brain by conducting a metabolomic analysis of cortical tissue from 5xFAD mice treated with increasing concentrations of CAW. Tissue was collected from 8-month-old male and female 5xFAD mice and their wild-type littermates treated with CAW (0, 200, 500, or 1,000 mg/kg/d) dissolved in their drinking water for 5 weeks. High-performance liquid chromatography coupled to high-resolution mass spectrometry analysis was performed and relative levels of 120 annotated metabolites were assessed in the treatment groups. Metabolomic analysis revealed sex differences in the effect of the 5xFAD genotype on metabolite levels compared to wild-type mice, and variations in the metabolomic response to CAW depending on sex, genotype, and CAW dose. In at least three of the four treated groups (5xFAD or wild-type, male or female), CAW (500 mg/kg/d) significantly altered metabolic pathways related to purine metabolism, nicotinate and nicotinamide metabolism, and glycerophospholipid metabolism. The results are in line with some of our previous findings regarding specific mechanisms of action of CAW (e.g., improving mitochondrial function, reducing oxidative stress, and increasing synaptic density). Furthermore, these findings provide new information about additional, potential mechanisms for the cognitive-enhancing effect of CAW, including upregulation of nicotinamide adenine dinucleotide in the brain and modulation of brain-derived neurotrophic factor. These metabolic pathways have been implicated in the pathophysiology of Alzheimer’s disease, highlighting the therapeutic potential of CAW in this neurodegenerative disease.

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It has been established that cell binding factors in yeast that contribute to flocculation in brewing occur owing to three phenomena: zymolectin binding, hydrophobic interactions and, to a lesser degree, surface charge neutralization (1). Changes in cell surface hydrophobic interactions, in particular, have been known to be involved in flocculation for some time and in fact our laboratory has previously determined that two strains of brewing yeast cells reach maximum flocculation potential with a concurrent increase in cell wall hydrophobicity (1,2). Furthermore, during an investigation of oxylipin distribution in brewing yeasts, it was shown that a particular hydrophobic carboxylic acid, 3-hydroxy oxylipin (3-OH oxylipin), was localized to the cell wall at flocculation onset (3). Thus, the level of 3-OH oxylipins showed strong potential as a putative predictor of flocculation.It was the general working hypothesis of our recent study that changes in cell wall hydrophobicity, which is an important contributing force to yeast cell flocculation, are due to oxylipin formation. While our laboratory has conducted extensive work to date on flocculation and measuring cell wall hydrophobicity, there have been no studies that correlate flocculation, cell wall hydrophobicity and cell wall oxylipin concentration as a function of fermentation time. Other research groups have investigated 3-OH oxylipin levels in different species of brewer's yeast, notably the Kock Laboratory, and they were able to detect two 3-OH oxylipins, in particular, 3-OH 8:0 and 3-OH 10:0 (3,4). However, to our knowledge other laboratories have not investigated Saccharomyces cerevisiae 3-OH oxylipins nor monitored their concentration over the course of a fermentation cycle.Our research was conducted in two main phases. In the first phase, the SMA strain of Saccharomyces cerevisiae was grown in yeast extract, peptone and dextrose (YEPD) broth to validate the experimental techniques and to investigate the merits of whole cell fatty acid analysis vs cell wall-associated fatty acid analysis. It was hypothesized that cell rupture and subsequent isolation of the cell wall ghosts would concentrate the cell wall-associated lipids. In the second phase, the yeast was grown by the miniature fermentation assay protocol (5) to more closely mimic industrial beer fermentations.For all sample types, lipids were isolated using a hexaneisopropanol (HIP) extraction (6) and fatty acid methyl esters (FAME) were prepared using a standard acid-catalysed transesterification protocol. FAME were analysed by GC-MS with a FFAP column (nitroterephthalic acid-modified polyethylene glycol phase, 30 m, i.d. 0.32 mm). A mixed bacterial acid methyl esther (BAME) standard containing 3-OH 12:0 and 3-OH 14:0 was used to determine the chromatographic properties of the oxylipins, the characteristic fragments of the 3-OH structure in GC-MS, and to ultimately aid in detecting 3-OH 8:0 and 3-OH 10:0 specifically.In both YEPD broth and the miniature fermentation assay (5), flocculation and cell...

No abstract

Yeast format and pitching rate are variables which can be easily manipulated in a distillery environment but are seldom altered. Fermentations using dried and liquid yeast were studied at laboratory scale and compared by application of a 4-parameter logistic model to measurements of the decline in apparent extract during fermentation. Congener analysis of new make distillate allowed comparison between compounds of interest produced during fermentation.  The liquid yeast format demonstrated a significant reduction (p<0.05) in lag time, which was 68% shorter than dried yeast. Despite this, longer overall fermentation times were observed due to a slower exponential phase as compared to the dried yeast format. Alteration of the yeast pitching rate using dried and liquid formats, demonstrated that high rates resulted in reduced lag times. The maximum fermentation rates (Vmax) were assessed from the fermentation models and no consistent trend could be identified. Dried yeast was observed to achieve its maximum fermentation rate when underpitched. Substantially higher Vmax ­values were obtained with overpitched liquid yeast fermentations, resulting in faster fermentations, compared to underpitched liquid yeast fermentations. The liquid yeast format created more esters compared to dried yeast. The concentration of ethyl esters generally trended downwards for fermentations pitched with less yeast which fully attenuated. By combining the results of these studies, distillers can make informed decisions to optimise spirit character, quality, and distillery production.