Content Of Free Phenolic Acids Research Articles

Steam explosion technology as a tool to alter the physicochemical properties of intermediate wheatgrass (Thinopyrum intermedium) bran

Products containing the perennial grain intermediate wheatgrass (IWG) have recently entered the market, but little is known about the effect of processing operations on its constituents. This study investigated the effect of steam explosion (SE) conditions, i.e., temperature (130, 150 or 170 °C) and residence time (5 or 10 min), spanning severity factors from 1.6 to 3.1, on physicochemical properties of IWG bran. Even the lowest temperature and shortest time combination (130 °C, 5 min), was sufficient to inactivate peroxidase, generally regarded as the most heat-stable enzyme in grains. Contents of free phenolic acids as well as water-extractable arabinoxylans significantly increased while phytic acid was reduced after SE. However, starch damage, free fatty acids as well as browning (all negatively affecting quality) increased with treatment severity. Thus, SE is a promising technology to reduce enzymatic activity, enhance phenolic and soluble fiber contents in IWG bran, but severity factors >2.5 may negatively affect quality.

Phenolic compounds in purple whole-wheat flour and bread: Comparative analysis

Whole-wheat flour of purple wheat varieties contains anthocyanins and other phenolic compounds with high antioxidant activity, which makes it a potential raw material for functional foods. The content and composition of phenolic compounds in whole-wheat flour depends on the genotype and weather conditions; in the bread, however, they also depend on the bread-making technology. This article offers a comparative analysis of phenolic compounds in purple whole-wheat flour and bread baked from this flour.
 The study featured purple soft spring wheat (Triticum aestivum L.) of two varieties, Nadira and Line 193, which were harvested in 2016 and 2017, and corresponding bread samples. The antioxidant activity and phenolic content were measured spectrophotometrically while the qualitative analysis relied on the method of high-performance liquid chromatography (HPLC). 
 In the hot and dry year of 2016, the content of bound phenolic acids reached 2.0–2.4 mg/g dry weight in the flour of both genotypes. In the cool and humid year of 2017, the content of anthocyanins in the Nadira flour increased by 2.7 times and amounted to 0.65 mg/g dry weight. However, the corresponding bread sample had a much lower phenolic content: soluble phenolics were halved, anthocyanins dropped by 3–4 times, and bound phenolic acids went down by 7–17 times. The content of bound phenolic acids in the flour correlated positively with the content of free phenolic acids in the bread. The HPLC analysis revealed an increase in the content of free hydroxycinnamic acids in the bread: p-coumaric acid was the most abundant and amounted to 0.14–0.22 mg/g dry weight.
 Conventional State Standard 27669-88 for bread making resulted in a total decrease in anthocyanins, bound phenolic acids, and most free phenolics. Therefore, this technology cannot be applied to functional bread. The results can help develop a breadmaking technology for purple wheat varieties.

Heterologous expression and enzymatic characteristics of sulfatase from Lactobacillus plantarum dy-1.

Barley, rich in bioactive components including dietary fiber, polyphenolic compounds and functional proteins, exhibits health benefits such as regulating glucose and lipid metabolism. Previous studies have found that the content and composition of free phenolic acids in barley may be significantly changed by fermentation with the laboratory patented strain Lactobacillus plantarum dy-1 (L. p dy-1), but the mechanism of enzymatic release of phenolic acid remains to be elucidated. Based on this, this study aimed to identify the key enzyme in L. p dy-1 responsible for releasing the bound phenolic acid and to further analyze its enzymatic properties. The Carbohydrate-Active enZYmes database revealed that L. p dy-1 encodes 7 types of auxiliary enzymes, among which we have identified a membrane sulfatase. The enzyme gene LPMS05445 was heterologous to that expressed in E. coli, and a recombinant strain was induced to produce the target protein and purified. The molecular weight of the purified enzyme was about 59.9 kDa, with 578.21 U mg-1 enzyme activity. The optimal temperature and pH for LPMS05445 expression were 40 °C and 7.0, respectively. Furthermore, enzymatic hydrolysis by LPMS05445 can obviously change the surface microstructure of dietary fiber from barley bran and enhance the release of bound phenolic acid, thereby increasing the free phenolic acid content and improving its physiological function. In conclusion, sulfatase produced by Lactobacillus plantarum dy-1 plays a key role in releasing bound phenolic acids during the fermentation of barley.

Phenolic compounds and antimicrobial activity of leaves of the genus Sorbus species and natural hybrids

The identification of new sources of biologically active substances is an actual direction of research in recent years, in particular, the demand for antimicrobial compounds and natural preservatives of plant origin is growing. Plants of the genus Sorbus L. are known in folk medicine, but for the rational use of plant material, there is a lack of systematic study of the features of the secondary metabolites’ accumulation and the spectrum of biological activity of plants during vegetation in different environmental conditions. In the present work, the seasonal dynamics of the total content of polyphenols, flavonoids and free phenolic acids in the leaves of rowan plants natural to the flora of Ukraine and introduced in the steppe region were investigated. The highest accumulation of phenolic compounds was found in the leaves of S. domestica, S. latifolia, S. hybrida, S. torminalis and S. aucuparia in the first half of June, and in S. aria and S. intermedia in May, which will serve as a criterion for selecting the best plant material to obtain biologically active compounds. The seasonal dynamics of the content of flavonoids and phenolic acids in the leaves of plants had significant species differences, which require more in-depth studies of the phytocompounds component composition. Antimicrobial activity of leaf ethanol extracts of rowan plant was found to be high against gram-negative bacterial strain Klebsiella pneumoniae B920 (especially the activity of S. aria, S. intermedia and S. aucuparia extracts) and Pseudomonas aeruginosa B907 (especially the activity S. torminalis and S. domestica), clinical gram-positive strains of Staphylococcus epidermidis (the highest activity of S. aria, S. domestica and S. intermedia extracts), as well as against clinical strains of fluconazole-resistant fungus Candida albicans (especially the activity of extracts of S. latifolia S. torminalis and S. intermedia). A conclusion was made about the prospects of using leaf extracts of the genus Sorbus plants as an economical and affordable natural source of biologically active polyphenols with a wide spectrum of antimicrobial activity. Further research may be aimed at elucidating the component composition of rowan leaf extracts and establishing the relationship between individual phytocompounds and the antimicrobial effects of plant extracts.

Effect of electrohydrodynamic drying on bee pollen biochemical pathways

The mechanism of ionic wind and electric field of electrohydrodynamic (EHD) drying dehydration stress on the biochemical and molecular basis of bee pollen is still unclear. In this study, metabolomics and proteomics were employed to analyze the changes in biochemicals and small-molecule metabolic compounds of bee pollen during the drying process using needle-to-plate and plate-to-plate electrode system. The results show that ionic wind and electric field contributed 85.0% and 15.0% respectively to the dehydration characteristics, with the electric field having a greater effect on the quality parameters. As compared to ionic wind, the ribosome, the citric acid cycle (TCA cycle), and proteasome pathway played a positive role in regulating the abiotic and biochemical responses of electric field dehydration. Both ionic wind and electric field changed the expression of functional proteins related to amino acid metabolism pathways, resulting in a decrease in the expression of characteristic metabolites such as L-phenylalanine, L-aspartic acid, and L-pyroglutamic acid from 114.27 × 107, 5.31 × 107, and 142.55 × 107 in fresh rape bee pollen to 57.46 × 107, 3.32 × 107, and 57.46 × 107 in needle-to-plate (N-P) electrode treated and 61.25 × 107, 2.47 × 107, as well as 33.82 × 107 in plate-to-plate (P-P) electrode treated samples. Additionally, the differential expression of proteasome pathway and the destruction of the structural integrity of the cell wall storing phenolic compounds resulted in the further interaction of protein-phenolic supercomplexes, which in turn changed the content of free phenolic acids in rape bee pollen. These findings elucidated the biochemical regulation strategy and protein-phenolic compound interaction mechanism of rape bee pollen during EHD drying processing, and further emphasized the synergistic mechanism of ionic wind and electric field.

The Effect of Various Forms of Sulfur on Soil Organic Matter Fractions and Microorganisms in a Pot Experiment with Perennial Ryegrass (Lolium perenne L.).

This article focuses on the agronomic evaluation of the supplementation of mineral NPKMg fertilizers with elemental sulfur, magnesium, potassium, or ammonium sulfates in pot experiments with ryegrass growing in a sandy Arenosol with very low sulfur content. A benefit evaluation was carried out on the basis of biomass production, crop nutritional status, and changes in the content of soil organic matter fractions. Furthermore, the total number of bacteria, nitrogen-fixing bacteria, and fungi was estimated using the qPCR technique in soil samples after 60 days of ryegrass growth. The combined application of NPKMg and sulfur or sulfate fertilizers significantly increased the summary yield of three cuttings of fresh ryegrass biomass in the range of 32.3% to 82.7%. The application, especially in the form of sulfates, significantly decreased the content of free phenolic acids. Furthermore, compared to the control, i.e., soil with NPKMg applied alone, an increase in the content of glomalin-related proteins and a decrease in the amount of water-soluble organic carbon compounds were observed. Neither the number of DNA marker copy numbers of the total bacterial community nor the nitrogen-fixing bacteria were noticeably different. In turn, the total number of genetic markers for fungi was significantly higher in soils with potassium or ammonium sulfates compared to the control soil. The general results suggest that the application of sulfur fertilizers with NPKMg mineral fertilizer can benefit crops and support soil fertility due to the stabilization of aggregates and the decrease in water-soluble organic compounds.

Penicillium fermentation combined with enzyme treatment to enhance the release of phenolic acids from wheat bran

Phenols from wheat bran play an important role in improving the physiological function of human body because of their potential antioxidant capacity. However, most of the phenols in wheat bran exist in the form of insoluble binding, which limits their application in the field of food and medicine. In this paper, the modification of wheat bran by Penicillium solid-state fermentation (SSF) was studied. It was found that the content of free phenolic acids in wheat bran was significantly correlated with the activity of key hydrolytic enzymes in the fermentation process. On the fifth day of Penicillium fermentation, the content of free phenolic acids was the highest, which was 750.98 μg/g, which was 1.78 times higher than that of the control. The release of free phenolic acids was highest when wheat bran was treated with compound enzyme at 300 U/mL. Furthermore, the structure of wheat bran was significantly changed by fermentation with enzyme addition. On the 5th day of fermentation, the content of free phenolic acids was as high as 1500 μg/g, which was twice as much as that of fermented bran and 3.56 times that of unfermented bran.

Alteration in phytochemicals from sweet maize in response to domestic cooking and frozen storage

Sweet maize has worldwide importance due to its high nutritional value and health benefits. In order to provide valuable health-related information to consumers, the phytochemicals profile of raw sweet maize kernels and those exposed to different treatments (cooking, frozen storage before cooking, sucrose addition during cooking, and blanching) was examined herein. Thus, carotenoids, tocopherols and free phenolic acids content was determined by liquid chromatography, while the content of water soluble sugars was analyzed by anion exchange chromatography. In response to immediate cooking, as well as, to blanching prior to shorter frozen storage and cooking afterwards, all hybrids exhibited a significant decrease in carotenoids, and a significant increase in concentration of tocopherols, fructose, glucose, protocatechuic, ferulic and p-coumaric acids, in comparison to the fresh samples. However, treatments with blanching prior to longer frozen storage and cooking afterwards, contributed only to increased tocopherols content. Distinct grouping of processed samples in comparison to their corresponding control samples, revealed the existence of unique linkage between changes in phytochemicals content upon treatment in a hybrid-dependent manner. Combined blanching prior to shorter frozen storage with sucrose addition during cooking is highly recommended as a potent tool for phytochemicals enhancement.

Arabinoxylans Release from Brewers' Spent Grain Using Extrusion and Solid-State Fermentation with Fusarium oxysporum and the Antioxidant Capacity of the Extracts.

Brewers’ spent grain (BSG) is the most abundant byproduct generated from the beer-brewing process. BSG is a material rich in hemicellulose, composed of arabinoxylans (AX). However, the high crosslinking of this material causes low availability of AX, for which it is necessary to apply different treatments. The objective of this research is to increase the release of arabinoxylans through solid-state fermentation with Fusarium oxysporum f. sp. lycopersici using extruded brewery spent grain. First, the BSG is subjected to two types of physical treatments: extrusion at 20% moisture, 200 rpm and 50 °C (BSGe), and blade milling (BSGm). The chemical composition is determined for each sample (BSG, BSGe and BSGm). Subsequently, the solid-state fermentation process (SSF) is carried out on each sample. The fermentation kinetics at 30 °C are monitored for 7 days. Once the SSF concludes, AX are extracted, and the purity of AX is determined by the phloroglucinol colorimetric assay. Finally, the total phenolic compounds, phenolic acids and antioxidant capacity by DPPH are quantified. No significant differences (p ≥ 0.05) in the protein, lipid, ash or total dietary fiber contents are found among the samples. No significant difference (p ≥ 0.05) in the content of soluble fiber is found, although BSGe and BSGm have higher values than BSG. On the other hand, the yields of soluble AX exhibit significant differences (p ≤ 0.05) among nonfermented samples (BSG, 0.03%; BSGm, 0.53%; BSGe, 0.70%) and with SSF (BSG, 2.95%; BSGm, 6.24%; and BSGe, 9.58%). In addition, the contents of free phenolic compounds and free phenolic acids and the percent inhibition of free extracts by 2,2-diphenyl-1-picrylhydrazyl (DPPH) differ significantly (p ≤ 0.05) between samples subjected to SSF and nonfermented samples. Therefore, extrusion and SSF treatment increase AX release from BSG as well as the antioxidant capacity of the extracts.

Free, soluble conjugated and insoluble bonded phenolic acids in Keemun black tea: From UPLC-QQQ-MS/MS method development to chemical shifts monitoring during processing

Phenolic acids, including benzoic acid and hydroxycinnamic acid derivatives, are the main compounds of black tea. An efficient and accurate analytical method to quantify ten phenolic acids was established and validated by ultra-performance liquid chromatography coupled with triple quadrupole mass spectrometry (UPLC-QQQ-MS/MS). The chemical shifts during the processing of Keemun black tea were analyzed and the phenolic acids were quantified. Compared with fresh tea leaves, after processing, the contents of free phenolic acids, including gallic acid, salicylic acid, p-coumaric acid, and ferulic acid, increased markedly. Still, the contents of soluble conjugated phenolic acids, including p-coumaroylquinic acid isomers and chlorogenic acid isomers, decreased. Furthermore, the total contents of lignin, and insoluble bonded phenolic acids decreased. The adduct of (-)-epigallocatechin gallate and 3-caffeoylquinic acid was detected in tea samples, and its content increased highly after fermentation. The developed and validated analytical method can be used to monitor the manufacturing process of black tea.

The effect of pro-ecological procedures and plant injury on the content of free phenolic acids in winter wheat and on the feeding and development of Oulema melanopus

Under laboratory conditions we have investigated the effect of the application of pro-ecological procedures (effective microorganisms and biostimulant Asahi SL) and plant injury on the production of free phenolic acids in winter wheat and on the feeding and development of Oulema melanopus. Wheat plants before reaching the BBCH 32 stage (the beginning of stem elongation) were treated with effective microorganisms and the biostimulant Asahi SL. Then, for 2 days, some of the plants were injured by O. melanopus and some were uninjured. The influence of factors was investigated in conditions under which the cereal leaf beetle had the possibility to choose their food (no-choice test or choice test). It was found that wheat plants produce on average 0.172% DM of free phenolic acids. It has been shown that O. melanopus males and females preferred wheat previously uninjured. Also, irrespective of whether the plants were previously injured or uninjured, the females of that pest species always that caused areally more extensive leaf losses than the males. Treating plants with effective microorganisms and biostimulant Asahi SL is a secondary factor, as compared to previous wheat injury. Additionally, in choice tests, both males and females O. melanopus much preferred feeding on plants unprovided with preparations, whereas in no-choice tests, the application of pro-ecological procedures does not reduce egg laying by pests, does not adversely affect embryogenesis length and does not reduce hatching L1.

Investigations into the Ability to Reduce Cinnamic Acid as Undesired Precursor of Toxicologically Relevant Styrene in Wort by Different Barley to Wheat Ratios (Grain Bill) during Mashing.

Styrene is a food-borne toxicant in wheat beer and due to its classification as possibly carcinogenic to humans by the International Agency for Research on Cancer in 2002, mitigation strategies had to be developed. Aiming at understanding the impact of the barley to wheat malt ratio (grain bill) during mashing on the contents of soluble and free (i) cinnamic, (ii) p-coumaric, and (iii) ferulic acid, precursors of (i) styrene and the desired vinyl aromatics (ii) 4-vinylphenol and (iii) 2-methoxy-4-vinylphenol in wheat beer, wort was prepared at four different barley to wheat malt ratios of 100:0, 25:75, 50:50, and 0:100 (w/w). Additionally, the malts were produced at different germination temperatures and aeration rates (12/32, 18/35, 18/25, 24/18, and 26/25 (°C; L/min)) to consider these two further parameters as well. Thereby, soluble and free phenolic acid contents in wort showed linear correlations to the percentage of wheat in the grain bill, highlighting the absence of synergistic effects when mixing barley and wheat malts. In contrast, the results described the phenolic acid contents as a function of the concentrations in the respective barley and wheat wort, multiplied by their percentage in the grain bill. However, a clear recommendation for favorable barley to wheat malt ratios leading to a decrease of soluble and free cinnamic acid in wort could not be made, as the contents in the present study proved to be highly dependent on the barley and wheat varieties used during mashing and the parameters applied during malting. This was not the case for p-coumaric acid for which a clear decrease of the soluble and free forms was found with increasing wheat malt contents. Differently, the soluble form of ferulic acid increased with an increasing percentage of wheat malt, while the free form decreased. The malting parameters clearly recommended high germination temperatures and low aeration rates when aiming at a reduction of undesired cinnamic acid in wort. Fortunately, soluble and free p-coumaric and ferulic acid contents were only slightly affected, indicating that the formation of the characteristic wheat beer aroma might not suffer when applying these favorable conditions for styrene reduction.

Phenolics and related in vitro functional activities of different varieties of fresh waxy corn: a whole grain

The polyphenol distribution in fresh waxy corns of different color varieties and their functional activities, which may be useful for treating various chronic diseases, were investigated. The in vitro antioxidant activity, and hypoglycemic and hypocholesterolemic effects of the free and bound corn phenolics were determined to evaluate the edible value of fresh waxy corn. The colored varieties contained more phenols than the common varieties (white and/or yellow). The total free phenolic acid content of the six varieties was 6637.73 µg/g DW (dry weight), which was slightly higher (P > 0.05) than that of the total bound form (6276.65 µg/g DW). The total free flavonoid content was 5850.09 µg/g DW, which was higher (P < 0.05) than that of the total bound form (4874.51µg/g DW). No bound anthocyanin was detected in the methanol extracts of the tested varieties. For all the varieties, free polyphenols contributed 86−100 % and 70−78 % of the 2, 2-diphenyl-1-picrylhydrazyl (DPPH) and hydroxyl radical scavenging abilities, respectively, and 100 % of the ferric reducing capacity. The free phenolics in fresh waxy corn showed better (P < 0.05) hypoglycemic effect than the bound form in terms of inhibition of α-amylase activity, whereas the bound phenolics of most varieties showed higher α-glucosidase inhibitory activity than the free forms. The free phenolics showed better (P < 0.05) glycocholesterol binding than the bound form for all varieties. The bound polyphenols showed better sodium cholate and taurocholate binding than the free form for most varieties. In conclusion, the difference between free and bound polyphenol content and functional activities indicates that fresh waxy corn can be potentially used for the development of functional food.

The Impact of Formulation on the Content of Phenolic Compounds in Snacks Enriched with Dracocephalum moldavica L. Seeds: Introduction to Receiving a New Functional Food Product.

A new type of multigrain snack has been designed containing varied additions of Moldavian dragonhead (Dracocephalum moldavica L.) seeds. The antioxidant properties and the general health benefits of this plant material have already been widely acknowledged. The research discussed herein aimed to investigate the influence of the formulation and expansion method (frying) on the content of polyphenolic compounds, individual phenolic acids, and antiradical properties of innovative snacks enriched with dragonhead seeds. The highest content of polyphenols (0.685 mg GAE/mL), free phenolic acids (47.052 µg/g of dry matter), and highest radical scavenging activity (96.23% towards DPPH) were found in the fried snacks enriched with 22% of seeds. In these samples, 11 phenolic acids were detected. Strong positive correlations were seen between the addition of dragonhead and the polyphenol content (r = 0.989) and between the quantity of the enriching additive and the content of free phenolic acids (r = 0.953). The research has shown that such innovative snacks have the potential to supply health-benefiting free phenolic acids, e.g., salicylic, isoferulic, ferulic, p-coumaric, vanillic. Our studies provide an introduction to the development of a new range of functional foods.

Antioxidant activities, tyrosinase inhibition activity and bioactive compounds content of broken rice fermented with Amylomyces rouxii

Solid state fermentation (SSF) utilizing filamentous fungus Amylomyces rouxii was investigated as a bio-processing strategy to enhance the bioactive properties of broken rice. Fermentation was carried out for 18 days and samples were withdrawn at 2-days interval. Established methods were deployed to assess the changes in bioactive properties and compounds content in fermented broken rice. The bioactive properties studied were total phenolic content (TPC), total flavonoid content (TFC), DPPH-radical scavenging activity and ferric-reducing antioxidant power (FRAP). Additionally, tyrosinase inhibition activity, which represents anti-pigmentation/browning property, was evaluated. Free phenolic acids and organic acids content were determined through high performance liquid chromatography (HPLC). The results showed that fermentation significantly increased the total phenolic content of broken rice from 0.03 mg GAE/g sample to 3.94 mg GAE/g sample and total flavonoid content from 0.04 to 1.71 mg QE/g sample. By the end of the fermentation, DPPH-radical scavenging of fermented broken rice was enhanced to 94.22%, compared to 9.03% in the unfermented sample. It was also observed that FRAP and tyrosinase inhibition activity of fermented broken rice were improved up to 39- fold and 50-fold, respectively. Kojic acid, a potent antioxidant and tyrosinase inhibitor, was detected in fermented broken rice, along with oxalic and ascorbic acid. Gallic, protocatechuic and 4-hydroxybenzoic acids were enhanced upon fermentation. This study manifested the positive effect of broken rice after fermentation with A. rouxii and thus revealed the potential of fermented broken rice as a promising natural bio-ingredients in food, cosmetics and medicinal products.

Study of continuous flow ultrasonication to improve total phenolic content and antioxidant activity in sorghum flour and its comparison with batch ultrasonication

Ultrasonic technology was applied to release the phenolics bound with starch and protein matrix in order to enhance total phenolic content (TPC) and antioxidant activity (AA) of the sorghum flour. Both the continuous flow and batch ultrasonication were implied with independent variables such as flour to water ratio (FWR), ultrasonication intensity (UI), and ultrasonication time (UT) with an additional variable as flow rate (FR) in continuous flow ultrasonication. All the process variables showed a significant effect on the corresponding ultrasonication process. The optimal conditions for the continuous flow ultrasonication were a FWR of 10% w/v, an UI of 20 W/cm2, an UT of 130 s, and 15 ml/s FR which produced a maximum values of 70.9 mg GAE/100 g dry matter (d.m.) for TPC and 143.9 µmol TE/100 g d.m. for AA. Regarding the batch ultrasonication, the maximum values were 65.6 mg GAE/100 g d.m. and 141.0 µmol TE/100 g d.m. for TPC and AA, respectively at optimum conditions of 10% w/v FWR, 30 W/cm2 UI, and 200 s UT. When comparing with the batch ultrasonication, the continuous flow process saved 35% time and 33% of energy consumption to obtain comparatively higher TPC and AA of the sorghum flour. Ultrasonication improved free phenolic acid content by releasing bound phenolics in the sorghum flour. Impact of various process parameters on specific energy was analyzed during both the processes, and influence of energy on TPC and AA of the sorghum flour was also observed for the batch and continuous flow ultrasonication.

The Role of Endogenous Enzymes during Malting of Barley and Wheat Varieties in the Mitigation of Styrene in Wheat Beer.

Knowledge of the biochemical processes responsible for the release of phenolic acids (precursors of vinyl aromatics) during malting is important to find mitigation strategies for the toxicologically relevant styrene (formed from cinnamic acid) in wheat beer. Therefore, grain and malts of four barley and three wheat varieties were screened for the activities of various enzymes and the amounts of nonstarch polysaccharides (to which the phenolic acids are bound to a certain extent). During malting, a very strong degradation of β-glucan, synonymous to a depletion of the cell walls, was found, suggesting that a partial degradation of cell walls cannot have an effect on the release of phenolic acids. In barley malts, water-extractable arabinoxylan contents were between 0.59 and 0.79 g/100 g dm and in wheat malts between 0.93 and 1.51 g/100 g dm. Additionally, higher soluble ferulic acid contents in wheat wort compared to barley wort indicated that the degradation of nonstarch polysaccharides has an impact on the release of phenolic acids. For the feruloyl esterase, higher activities were found in malts of the barley varieties. However, this fact was not reflected by the free phenolic acid contents in those malts. Correlation coefficients between the protease activity and the feruloyl esterase, α- and β-amylase, and β-glucanase activities were proven to be insignificant, highlighting that the protease activity had no effect on the activities of these other enzymes.

Polyphenol Composition and Antioxidant Potential of Instant Gruels Enriched with Lycium barbarum L. Fruit.

Goji fruit (Lycium barbarum L.) has been identified as a polyphenolic compound plant source of noted richness. It also contains polysaccharides, carotenoids, vitamins and minerals, fatty and organic acids. The purpose of the presented research was to produce innovative instant corn gruels with various dry goji berry contents (1, 3 and 5%), to determine the level of included polyphenolic compounds (including individual free phenolic acids) and to assess the antioxidant properties of these functional-food products. A further objective was to identify the optimum value of one of the most important production parameter, the rotational speed of the extruder’s screw during gruel processing. The undertaken chromatographic analysis (LC-ESI-MS/MS) showed a wide variety of available phenolic acids. In the samples with 5% addition of fruit, eight phenolic acids were detected, whereas in the corn gruel without additives, only five were noted. The antioxidant activity, the content of free phenolic acids and the sum of polyphenols increased with increase of the functional additive. For all goji content, screw speeds of 100 and 120 rpm rather than 80 rpm resulted in higher polyphenol amounts and greater Trolox equivalent antioxidant capacity, as well as higher ability to scavenge DPPH.

Influence of Thermal Processing on Free and Bound Forms of Phenolics and Antioxidant Capacity of Rice Hull (Oryza sativa L.).

The objective of this study was to evaluate the effects of heat treatment on the phenolics and antioxidant activity of rice hull. Heat treatment was performed at temperatures 80∼140°C for 1∼5 h, and the heated rice hull was extracted with 80% (v/v) methanol in an ultrasonic bath. The highest total polyphenol and flavonoid content (10.68 mg gallic acid equivalents/g and 1.83 mg catechin equivalents/g, respectively) occurred in rice hull heated at 130°C for 5 h. During heat treatment, the content of free phenolic acids increased compared with that of the bound phenolic acids. The highest 2,2’-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) radical scavenging activity and reducing power was observed in rice hull heated at 140°C for 3 h. The highest OH radical scavenging activity was 75.30% in rice hull heated at 140°C for 5 h. These results suggested that heat treatment was an efficient method to enhance the antioxidant characteristics of rice hull.

Fermentation of Wheat Bran and Whey Permeate by Mono-Cultures of Lacticaseibacillus rhamnosus Strains and Co-culture With Yeast Enhances Bioactive Properties.

The aim of this work was to obtain a bioingredient (BI) with bioactive properties through the solid fermentation of a wheat bran-whey permeate (WB/WP) mixture with three strains of Lacticaseibacillus rhamnosus (R0011, ATCC 9595, and RW-9595M) in mono or co-culture with Saccharomyces cerevisiae. The choice of these strains was based on their capacity to produce the same exopolysaccharide (EPS), but at different yields. The solid fermentation of WB/WP revealed a similar growth pattern, sugar utilization and metabolite production between strains and types of culture. Lactic acid, soluble protein, free amino acid and phenolic compound content in BI were compared to NFWB. Water soluble polysaccharides (including EPS) were significantly increased in co-culture for (44%) ATCC 9595, (40%) R0011 and (27%) RW-9595M. The amount of bound Total Phenolic Content (TPC) as well as the antioxidant activity in BI were higher after fermentation. The free phenolic acid content was higher after fermentation with ATCC 9595 (53–59%), RW-9595M (45–46%), and R0011 (29–39%) compared to non-fermented NFWB. Fermentation by these strains increased the amounts of free caffeic acid and 4-hydroxybenzoic acid in both types of culture. The bound phenolic acid content was enhanced in co-culture for the BI obtained from the highest EPS producer strain RW-9595M which was 30% higher than NFWB. After in vitro digestion, bioaccessibility of free total phenolic acids was improved by more than 40% in BI compared to NFWB. The co-culture increased recovery of TPC (%) and antioxidant activity compared to monoculture for the strains in digested product. In contrast, the recovery of bound total phenolic acids in co-culture was 33 and 38% lower when compared to monoculture for R0011 and RW-9595M. Our findings provide new insights into the impact of LAB/yeast co-culture on the bioactive properties of fermented wheat bran.