The effect of the addition of selected phenolic acids on the rheological properties of heated solutions of whey proteins

This study measured the flow behaviour of whey protein isolate mixtures with cinnamic or ferulic acids. Samples were heated in a vacuum (80 °C, –0.9 atm, 280 r.p.m., 0.5 h). The flow curves of all samples showed a non- Newtonian shear thinning flow and the viscoelastic properties were typical for weak gel systems. At pH 6.0, 6.7, and 8.0, the highest shear stress values were obtained with 20, 40, and 40 mg of cinnamic acid g–1 protein, respectively. At pH 6.0, the use of ferulic acid (20 mg g–1 protein) resulted in the elevation of shear stress values, but at pH 8.0, ferulic acid caused a decrease in shear stress values in comparison to cinnamic acid. The thixotropic area (AT) was increased in mixtures containing 20–40 mg cinnamic acid g–1 protein (at pH 6.7) and 20 mg of cinnamic acid g–1 protein (at pH 6.0). Similarly, the addition of ferulic acid (40 and 20 mg g–1 protein at pH 6.7 and 6.0, respectively) caused a significant increase in AT. At pH 8.0, no significant differences in AT values were observed between samples. Such systems can be applied with reference to health promoting foods such as WPI-based desserts

Gentisic Acid, Salicylic Acid, Total Phenolic Content and Cholinesterase Inhibitory Activities of Red Wines Made from Various Grape Varieties

Alzheimer’s disease is characterised by a decrease in acetylcholine (ACh) levels in the brain due to the activity of acetylcholinesterase (AChE) and butyrylcholinesterase (BChE). As a result, disorders in cholinergic transmission are observed, leading to cognitive impairment. In this work, the inhibition of AChE and BChE activities by red wines made of various grape varieties was determined for the first time.  There was no significant difference in the polyphenol content between the grape varieties; nevertheless, there were significant differences in the content of gentisic acid and salicylic acid, and in the inhibition of AChE and BChE between the wine samples. A statistically significant correlation between AChE inhibitory activity and salicylic acid, as well as between BChE inhibitory activity and total phenolic content, was recorded. In model solution studies, it was shown that salicylic acid effectively inhibited BChE activity at concentrations similar to the maximum concentrations found in the test wines. Hierarchical cluster analysis (HCA) revealed that the wines could be divided into three groups. Cabernet Sauvignon and Syrah wines had the highest content of salicylic acid and AChE inhibitory activity, as well as low BChE inhibitory activity. Pinot noir, Tempranillo, Regent and Rondo wines showed the lowest content of salicylic acid and low AChE inhibitory activity. Garnacha tinta, Merlot, Montepulciano and Negroamaro wines had a medium content of salicylic acid, and the highest or medium BChE inhibitory activity. This work is important for both the wine industry and for health protection

Common and Distant Structural Characteristics of Feruloyl Esterase Families from Aspergillus oryzae

Background: Feruloyl esterases (FAEs) are important biomass degrading accessory enzymes due to their capability of cleaving the ester links between hemicellulose and pectin to aromatic compounds of lignin, thus enhancing the accessibility of plant tissues to cellulolytic and hemicellulolytic enzymes. FAEs have gained increased attention in the area of biocatalytic transformations for the synthesis of value added compounds with medicinal and nutritional applications. Following the increasing attention on these enzymes, a novel descriptor based classification system has been proposed for FAEs resulting into 12 distinct families and pharmacophore models for three FAE sub-families have been developed. Methodology/Principal Findings: The feruloylome of Aspergillus oryzae contains 13 predicted FAEs belonging to six sub-families based on our recently developed descriptor-based classification system. The three-dimensional structures of the 13 FAEs were modeled for structural analysis of the feruloylome. The three genes coding for three enzymes, viz., A.O.2, A.O.8 and A.O.10 from the feruloylome of A. oryzae, representing sub-families with unknown functional features, were heterologously expressed in Pichia pastoris, characterized for substrate specificity and structural characterization through CD spectroscopy. Common feature-based pharamacophore models were developed according to substrate specificity characteristics of the three enzymes. The active site residues were identified for the three expressed FAEs by determining the titration curves of amino acid residues as a function of the pH by applying molecular simulations. Conclusions/Significance: Our findings on the structure-function relationships and substrate specificity of the FAEs of A. oryzae will be instrumental for further understanding of the FAE families in the novel classification system. The developed pharmacophore models could be applied for virtual screening of compound databases for short listing the putative substrates prior to docking studies or for post-processing docking results to remove false positives. Our study exemplifies how computational predictions can complement to the information obtained through experimental methods. © 2012 Udatha et al.published_or_final_versio

Inhibition of cholinesterases by phenolic acids detected in beer: A dose-response model approach

This study tested the in vitro anti-acetylcholinesterase (AChE) and anti-butyrylcholinesterase (BChE) activities of simple phenolic acids using Ellman’s spectrophotometric method. 15 phenolic acids (at levels found in beer) exerted differentiated anticholinesterase activities, with the most efficient being chlorogenic, p-coumaric, p-hydroxybenzoic and caffeic acids. When present at levels similar to those detected in plasma after beer consumption (500 ml), vanillic, caffeic, syringic and p-coumaric acids exhibited anti-BChE activity. Phenolic acids were not interactive in a complex solution at concentrations found in plasma after beer consumption. Combined phenolic acids (p-hydroxyphenylacetic, ferulic, vanillic, caffeic, syringic, sinapic and p-coumaric, at 0.01 mM) showed both anticholinesterase activity and synergy between the individual compounds. Also, synergy was found in the case of selected pairs of phenolic acids (each at 0.01 mM), calculated using the method of expected inhibition and the interactive index of combination. These results support the idea that simple phenolic acids from beer can play a role in neuroprotection, but further studies need to be conducted.Keywords: Acetylcholinesterase, Alzheimer’s disease, beer, butyrylcholinesterase, phenolic acidsAfrican Journal of Biotechnology Vol. 12(14), pp. 1675-168

Arabinoxylans from malt as a source of natural antioxidant ferulic acid and dietary fibre in beer

Ostatnio obserwuje się tendencję do zastępowania syntetycznych przeciwutleniaczy dodawanych do żywności produktami naturalnymi zawierającymi takie substancje. W artykule scharakteryzowano rolę, jaką kwas ferulowy, główny kwas fenolowy jęczmienia i słodu, odgrywa w kształtowaniu potencjału przeciwutleniającego piwa. Przedstawiono aktualny stan wiedzy na temat aktywności przeciwutleniającej kwasu ferulowego mierzonej w warunkach in vitro i in vivo, ponadto szczegółowo przedstawiono budowę, funkcje jak również znaczenie technologiczne arabinoksylanów i b-glukanów w czasie słodowania i produkcji piwa. Wolny kwas ferulowy dodany w niskim stężeniu do piwa jest bardzo stabilny, podczas gdy w wyższych dawkach jego zawartość gwałtownie zmniejsza się. Aktywność przeciwutleniająca kwasu ferulowego w piwie jest podobna do aktywności (+)katechiny. Jednak (+)katechina powoduje powstanie zmętnienia w piwie przy stężeniu o wiele niższym niż ma to miejsce w przypadku kwasu ferulowego. W wyższych stężeniach kwas ferulowy może więc wpływać pozytywnie na stabilność koloidalną piwa. Będąc aktywnym przeciwutleniaczem z jednym miejscem aktywnym, kwas ferulowy może blokować miejsca aktywne białek wywołujących zmętnienia i w ten sposób uniemożliwiać katechinie i jej pochodnym dostęp do białek w miejscach wiązań z polifenolami. Z tego względu, zwiększanie stężenia kwasu ferulowego w piwie w formie połaczeń z cukrami może przyczynić się do zwiększenia cech prozdrowotnych piwa przy minimalnych nakładach na modyfikację procesu produkcji piwa, a zwłaszcza zacierania słodu.Recently, a tendency is observed to replace synthetic antioxidants, which are added to food, by natural products containing the same substances. This paper deals with the role the ferulic acid, a main phenolic acid of barley and malt, plays in shaping the antioxidant potential of beer. There is also presented the current state of knowledge of the ferulic acid’s antioxidant activity measured under the in vitro and in vivo conditions. Furthermore, the paper contains a detailed description of the structure, functions, and technological significance of arabinoxylans and b-glucans under the processes of beer malting and brewing. If the amounts of free ferulic acid added to beer have low concentration rates, then, the ferulic acid is very stable, whereas the highly concentrated free ferulic acid amounts cause a very rapid decrease in the ferulic acid content. The antioxidant activity of ferulic acid in beer is similar to the antioxidant activity of (+)-catechin. However, (+)-catechin causes beer to haze at a concentration rate being much lower if compared with the ferulic acid. Therefore, the ferulic acid at higher concentration rates can positively impact the colloidal stabilization of beer. As an active antioxidant with one active site, the ferulic acid can block active sites of the haze-generating proteins and, in this way, make it impossible for (+)-catechin and its derivatives to access proteins in the sites with polyphenol bonds. Thus, the increased concentration rates of ferulic acid in beer in the form of combination with sugars can contribute to enhancing the health-promoting properties of beer alongside low outlays necessary to modify the beer manufacturing process, especially the mashing process

Charakterystyka enzymow pochodzenia mikrobiologicznego bioracych udzial w degradacji arabinoksylanow i ich rola w pozyskiwaniu kwasu ferulowego z wyslodzin piwowarskich

Celem pracy było scharakteryzowanie enzymów pochodzenia bakteryjnego i grzybowego biorących udział w degradacji arabinoksylanów. W szczególności scharakteryzowano esterazy kwasu ferulowego, ksylanazy i acetyloesterazy. Przedstawiono stan badań nad pozyskiwaniem kwasu ferulowego z wysłodzin piwowarskich i innych materiałów roślinnych, po zastosowaniu oczyszczonych enzymów lub preparatów enzymatycznych pochodzenia mikrobiologicznego. Wysłodziny piwowarskie są najcenniejszym produktem odpadowym przemysłu piwowarskiego, bogatym w cenne składniki żywieniowe, np. białko, błonnik pokarmowy i kwasy tłuszczowe. Kwas ferulowy jest naturalnym, silnym przeciwutleniaczem występującym pospolicie w ziarniakach roślin Graminaceae i w produktach ubocznych przemysłu piwowarskiego - w wysłodzinach piwowarskich. Może być on przekształcany na drodze mikrobiologicznej do innych związków wykorzystywanych przemysłowo, np. przeciwutleniacza kwasu kawowego lub waniliny, cenionego związku aromatycznego żywności. (abstrakt oryginalny)The aim of this review was to characterise of bacterial and fungal enzymes taking part in the degradation of arabinoxylans. This study especially describes ferulic acid esterase, xylanase and acethylesterase. This paper presents the sum of results concerning the possibility of ferulic acid production from barley spent grain using purified enzymes or commercial enzyme preparations of microbial origin. Barley spent grain is the most valuable by-product of brewing industry, rich in precious dietary components like proteins, dietary fiber, fatty acids and others. Ferulic acid is a natural, strong antioxidant commonly present in Graminaceae family plants and in a number of by-products of brewing industry - barley spent grain. Ferulic acid can be also microbiologically transformed into other compounds used in food industry, like antioxidant caffeic acid or vanillin, precious flavoring agent. (original abstract