Assessing Antioxidant Properties, Phenolic Compound Profiles, Organic Acids, and Sugars in Conventional Apple Cultivars (Malus domestica): A Chemometric Approach.

This study analyzed the phenolic compounds, organic acids, sugars, and antioxidant activity in different conventional apple cultivars (Malus domestica) from the Serbian market. Polyphenol profiles, sugars, and organic acid contents were analyzed by HPLC, and antioxidant activity was examined by DPPH and FRAP. Notable findings included variations in phenolic compound presence, with certain compounds detected only in specific cultivars. 'Red Jonaprince' exhibited the highest arbutin (0.86 mg/kg FW) and quercetin-3-rhamnoside content (22.90 mg/kg FW), while 'Idared' stood out for its gallic acid content (0.22 mg/kg FW) and 'Granny Smith' for its catechin levels (21.19 mg/kg FW). Additionally, malic acid dominated among organic acids, with 'Granny Smith' showing the highest content (6958.48 mg/kg FW). Fructose was the predominant sugar across all cultivars. Chemometric analysis revealed distinct groupings based on phenolic and organic acid profiles, with 'Granny Smith' and 'Golden Delicious' exhibiting unique characteristics. Artificial neural network modeling effectively predicted antioxidant activity based on the input parameters. Global sensitivity analysis highlighted the significant influence of certain phenolic compounds and organic acids on antioxidant activity.

Astringent Gallic Acid in Red Wine Regulates Mechanisms of Gastric Acid Secretion via Activation of Bitter Taste Sensing Receptor TAS2R4.

Red wine is rich in phenolic compounds, which chiefly determine its characteristic taste. One of its major phenolic acid constituents for which an astringency, yet no clear contribution to bitter taste has been reported, is gallic acid (GA). In previous studies, we have demonstrated bitter-tasting constituents to regulate cellular proton secretion (PS) as a key mechanism of gastric acid secretion via activation of bitter taste sensing receptors (TAS2Rs). Here, we hypothesized a contributing role of GA to the red wine-stimulated effect on PS in human gastric tumor cells (HGT-1 cells). Sensory analyses revealed that 10 µM GA as the lowest concentration tested more bitter than tap water, with increasing bitter ratings up to 1000 µM. In HGT-1 cells, the concentration of 10 µM GA evoked the most pronounced effect on PS secretion, either when added to cells as in-water solution or when spiked to a red wine matrix. GA-spiking of Zweigelt and Blaufränkisch red wine samples up to a concentration of 10 µM resulted in an equally stimulated PS, whereas the non-GA-spiked wine samples demonstrated contrary effects on PS, indicating a functional role of GA on PS. Involvement of TAS2R4 in the GA-induced PS was verified by means of an HGT-1 homozygote CRISPR-Cas9 TAS2R4 knockout approach. Moreover, gene expression analyses revealed GA to increase TAS2R4. These results demonstrate a functional role of TAS2R4 in GA-evoked PS as a key mechanism of gastric acid secretion aiding digestion. Moreover, our data provide mechanistic insights, which will help to produce stomach-friendly red wines.

Polysulfides Applied as Formulated Garlic Extract to Protect Tomato Plants against the Root-Knot Nematode Meloidogyne incognita.

The devastating root-knot nematode Meloidogyne incognita can cause severe damage to field and greenhouse crops. Due to high economic losses, alternative products are essential to replace banned or strictly regulated nematicides that affect human health and/or the environment. Garlic based products have been previously investigated as environmentally friendly nematicides and their active substances, diallyl polysulfides exist as formulated nematicides on the market. We tested the garlic-based nematicide NEMguard® DE as protective of tomato roots. In vitro evaluation of the lethal concentration (LC) showed strong nematicidal activity with LC50 of 0.8 mg/mL after 96 h and LC90 of 1.5 mg/mL. NEMguard® DE showed protective effect against M. incognita as a single application in small pots and a second application further reduced root galling, significantly. Large greenhouse trials were carried out in two consecutive years to test single and monthly applications of NEMguard® DE. In both years, no controlling effect could be observed on M.incognita. We assume that the silt content of the loamy sandy soil used had an effect on the polysulfides, inhibiting their nematicidal effect. We conclude that further experiments are necessary to investigate the nematicidal potential of NEMguard® DE under different soil compositions or as a different formulation.

Aromatypicity of Austrian Pinot Blanc Wines.

Pinot blanc is a grape variety found in all wine-growing regions of Austria. However, there are only few scientific studies which deal with the aroma of wines of this variety. In the course of this project, the relationship between aroma profile and the typicity of Austrian Pinot blanc wines was studied. The aim was to describe the typicity and to find significant differences in aroma profiles and aroma descriptors of typical and atypical Pinot blanc wines. Since the typicity of a jointly anchored prototype is embedded in the memory, typical attributes for Austrian Pinot blanc wines were first identified by consumers and experts or producers. According to this, 131 flawless commercial Austrian wines of the variety Pinot blanc of the vintages 2015 to 2017 were analysed for more than 100 volatile substances. The wines of the vintages 2015 to 2017 were judged by a panel of producers and experts for their typicity; furthermore, the wines of the vintage 2017 were also evaluated by a consumer panel and a trained descriptive panel. Subsequently, typical and atypical wines were described by the trained descriptive panel. It was found that Pinot blanc wines typical of Austria showed significantly higher concentrations of the ester compounds ethyl hexanoate, ethyl butanoate, ethyl octanoate, ethyl decanoate, methyl hexanoate, hexyl acetate and isoamyl acetate, while atypical wines had higher concentrations of free monoterpenes such as linalool, trans-linalool oxide, nerol oxide, nerol and alpha-terpineol. The sensory description of typical Pinot blanc wines was significantly more pronounced for the attribute "yellow pome fruit", and tended to be more pronounced for the attributes "green pome fruit", "pear", "walnut", "pineapple", "banana" and "vanilla", while the atypical Pinot blanc wines were described more by the attribute "citrus". These findings could help to ensure that, through targeted measures, Austrian Pinot blanc wines become even more typical and distinguish themselves from other origins such as Germany or South Tyrol through a clear concept of typicity.

Evaluation of fluopyram for the control of Ditylenchus dipsaci in sugar beet.

Fluopyram, a succinate dehydrogenase inhibitor fungicide, has shown potential in controlling Meloidogyne incognita and Rotylenchus reniformis in tomato. The effectiveness of this compound for the control of Ditylenchus dipsaci in sugar beet was evaluated. In this study, laboratory, growth chamber, glasshouse, and field experiments were conducted. In a motility bioassay, the EC50 value was determined with 3.00 µg/ml a.i. after 72 h exposure to fluopyram. The growth chamber experiment did not show any effects on D. dipsaci penetration rate; however, field experiments revealed a positive effect of fluopyram applied at planting in reducing D. dipsaci infectivity. The glasshouse experiment confirmed a limited effect of fluopyram on D. dipsaci population development. Under field conditions, despite a reduction of D. dipsaci penetration rates in spring, fluopyram was not effective in reducing the population development until harvest. Consequently, D. dipsaci densities in plant tissue and soil were high at harvest and not different among treatments. However, root-rot symptoms were significantly reduced at harvest. Fluopyram applied at planting showed good potential to reduce root-rot symptoms caused by D. dipsaci in sugar beet. However, for the long-term reduction of nematode populations in soil, further integrated control measures are needed to reduce the risks of substantial yield losses by D. dipsaci.Fluopyram, a succinate dehydrogenase inhibitor fungicide, has shown potential in controlling Meloidogyne incognita and Rotylenchus reniformis in tomato. The effectiveness of this compound for the control of Ditylenchus dipsaci in sugar beet was evaluated. In this study, laboratory, growth chamber, glasshouse, and field experiments were conducted. In a motility bioassay, the EC50 value was determined with 3.00 µg/ml a.i. after 72 h exposure to fluopyram. The growth chamber experiment did not show any effects on D. dipsaci penetration rate; however, field experiments revealed a positive effect of fluopyram applied at planting in reducing D. dipsaci infectivity. The glasshouse experiment confirmed a limited effect of fluopyram on D. dipsaci population development. Under field conditions, despite a reduction of D. dipsaci penetration rates in spring, fluopyram was not effective in reducing the population development until harvest. Consequently, D. dipsaci densities in plant tissue and soil were high at harvest and not different among treatments. However, root-rot symptoms were significantly reduced at harvest. Fluopyram applied at planting showed good potential to reduce root-rot symptoms caused by D. dipsaci in sugar beet. However, for the long-term reduction of nematode populations in soil, further integrated control measures are needed to reduce the risks of substantial yield losses by D. dipsaci.

Identification of Catechin, Syringic Acid, and Procyanidin B2 in Wine as Stimulants of Gastric Acid Secretion.

Organic acids of wine, in addition to ethanol, have been identified as stimulants of gastric acid secretion. This study characterized the influence of other wine compounds, particularly phenolic compounds, on proton secretion. Forty wine parameters were determined in four red wines and six white wines, including the contents of organic acids and phenolic compounds. The secretory activity of the wines was determined in a gastric cell culture model (HGT-1 cells) by means of a pH-sensitive fluorescent dye. Red wines stimulated proton secretion more than white wines. Lactic acid and the phenolic compounds syringic acid, catechin, and procyanidin B2 stimulated proton secretion and correlated with the pro-secretory effect of the wines. Addition of the phenolic compounds to the least active white wine sample enhanced its proton secretory effect by 65 ± 21% (p < 0.05). These results indicate that not only malic and lactic acid but also bitter and astringent tasting phenolic compounds in wine contribute to its stimulatory effect on gastric acid secretion.

Malolactic enzyme from Oenococcus oeni: heterologous expression in Escherichia coli and biochemical characterization.

Malolactic enzymes (MLE) are known to directly convert L-malic acid into L-lactic acid with a catalytical requirement of nicotinamide adenine dinucleotide (NAD (+) ) and Mn ( 2+) ; however, the reaction mechanism is still unclear. To study a MLE, the structural gene from Oenococcus oeni strain DSM 20255 was heterologously expressed in Escherichia coli, yielding 22.9 kU l (-1) fermentation broth. After affinity chromatography and removal of apparently inactive protein by precipitation, purified recombinant MLE had a specific activity of 280 U mg (-1) protein with a recovery of approximately 61%. The enzyme appears to be a homodimer with a molecular mass of 128 kDa consisting of two 64 kDa subunits. Characterization of the recombinant enzyme showed optimum activity at pH 6.0 and 45°C, and Km, Vmax and kcat values of 4.9 mM, 427 U mg (-1) and 456 sec (-1) for L-malic acid, 91.4 µM, 295 U mg (-1) and 315 sec (-1) for NAD (+) and 4.6 µM, 229 U mg (-1) and 244 sec (-1) for Mn ( 2+) , respectively. The recombinant MLE retained 95% of its activity after 3 mo at room temperature and 7 mo at 4°C. When using pyruvic acid as substrate, the enzyme showed the conversion of pyruvic acid with detectable L-lactate dehydrogenase (L-LDH) activity and oxidation of NADH. This interesting observation might explain that MLE catalyzes a redox reaction and hence, the requirements for NAD (+) and Mn ( 2+) during the conversion of L-malic to L-lactic acid.

Heterologous expression of Oenococcus oeni malolactic enzyme in Lactobacillus plantarum for improved malolactic fermentation.

Lactobacillus plantarum is involved in a multitude of food related industrial fermentation processes including the malolactic fermentation (MLF) of wine. This work is the first report on a recombinant L. plantarum strain successfully conducting MLF. The malolactic enzyme (MLE) from Oenococcus oeni was cloned into the lactobacillal expression vector pSIP409 which is based on the sakacin P operon of Lactobacillus sakei and expressed in the host strain L. plantarum WCFS1. Both recombinant and wild-type L. plantarum strains were tested for MLF using a buffered malic acid solution in absence of glucose. Under the conditions with L-malic acid as the only energy source and in presence of Mn2+ and NAD+, the recombinant L. plantarum and the wild-type strain converted 85% (2.5 g/l) and 51% (1.5 g/l), respectively, of L-malic acid in 3.5 days. Furthermore, the recombinant L. plantarum cells converted in a modified wine 15% (0.4 g/l) of initial L-malic acid concentration in 2 days. In conclusion, recombinant L. plantarum cells expressing MLE accelerate the malolactic fermentation.

Development of a device to measure human sound localization.

Measurements of human sound discrimination and localization are important for basic empirical and clinical applications. After a short survey of other methods such as evoked potentials, the development of a new device to measure human sound localization is described and its use illustrated with some examples. Built from a polyacrylic hemisphere or--in a later version--from an orbicular aluminum frame, the apparatus uses multiple speakers to emit auditory stimuli. The patient sits in the middle of the perimeter and has to press a button when a sound is perceived. In addition, the participant has to identify the correct speaker as the source of the sound. With this method it is possible to map the auditory field.

Characterization of two distinct glycosyl hydrolase family 78 alpha-L-rhamnosidases from Pediococcus acidilactici.

α-L-Rhamnosidases play an important role in the hydrolysis of glycosylated aroma compounds (especially terpenes) from wine. Although several authors have demonstrated the enological importance of fungal rhamnosidases, the information on bacterial enzymes in this context is still limited. In order to fill this important gap, two putative rhamnosidase genes (ram and ram2) from Pediococcus acidilactici DSM 20284 were heterologously expressed, and the respective gene products were characterized. In combination with a bacterial ß-glucosidase, both enzymes released the monoterpenes linalool and cis-linalool oxide from a muscat wine extract under ideal conditions. Additionally, Ram could release significant amounts of geraniol and citronellol/nerol. Nevertheless, the potential enological value of these enzymes is limited by the strong negative effects of acidity and ethanol on the activities of Ram and Ram2. Therefore, a direct application in winemaking seems unlikely. Although both enzymes are members of the same glycosyl hydrolase family (GH 78), our results clearly suggest the distinct functionalities of Ram and Ram2, probably representing two subclasses within GH 78: Ram could efficiently hydrolyze only the synthetic substrate p-nitrophenyl-α-L-rhamnopyranoside (V(max) = 243 U mg(-1)). In contrast, Ram2 displayed considerable specificity toward hesperidin (V(max) = 34 U mg(-1)) and, especially, rutinose (V(max) = 1,200 U mg(-1)), a disaccharide composed of glucose and rhamnose. Both enzymes were unable to hydrolyze the flavanone glycoside naringin. Interestingly, both enzymes displayed indications of positive substrate cooperativity. This study presents detailed kinetic data on two novel rhamnosidases, which could be relevant for the further study of bacterial glycosidases.

Root colonisation by the arbuscular mycorrhizal fungus Glomus intraradices alters the quality of strawberry fruits (Fragaria x ananassa Duch.) at different nitrogen levels.

BACKGROUND: Arbuscular mycorrhizal fungi (AMF) increase the uptake of minerals from the soil, thus improving the growth of the host plant. Nitrogen (N) is a main mineral element for plant growth, as it is an essential component of numerous plant compounds affecting fruit quality. The availability of N to plants also affects the AMF-plant interaction, which suggests that the quality of fruits could be affected by both factors. The objective of this study was to evaluate the influence of three N treatments (3, 6 and 18 mmol L(-1)) in combination with inoculation with the AMF Glomus intraradices on the quality of strawberry fruits. The effects of each factor and their interaction were analysed. RESULTS: Nitrogen treatment significantly modified the concentrations of minerals and some phenolic compounds, while mycorrhization significantly affected some colour parameters and the concentrations of most phenolic compounds. Significant differences between fruits of mycorrhizal and non-mycorrhizal plants were found for the majority of phenolic compounds and for some minerals in plants treated with 6 mmol L(-1) N. The respective values of fruits of mycorrhizal plants were higher. CONCLUSION: Nitrogen application modified the effect of mycorrhization on strawberry fruit quality.

Estrogenic activity in white and red wine extracts.

Red wine is enriched in resveratrol, trans-3,5,4'-trihydroxystilbene, a compound in grape skin that inhibits the development of pre-neoplastic lesions in mouse mammary tumor cells in culture and inhibits cancer cell proliferation in vitro. Grapes also contain other bioactive compounds including flavonoids, flavans, and anthocyanins. The estrogenic activities of extracts prepared from one white (Freie Weingärtner Wachau, Grüner Veltliner, Austria) and two red wines (Woodbridge, Cabernet Sauvignon, California; and Lenz Moser Prestige, Blaufränkisch Barrique, Austria) were examined and compared with those induced by estradiol (E(2)) and trans-resveratrol. First, the estrogenic activity of the wine extracts was evaluated in a yeast estrogen screen (YES) assay, in which yeast express copper-inducible estrogen receptor alpha (ERalpha) and an estrogen-response-element (ERE)-driven beta-galactosidase reporter. In YES, the white wine extract showed no estrogenic activity. In contrast, both of the red wine extracts showed estrogenic activity equivalent to that of 0.2 nM E(2). Similarly, the white wine extract showed no transcriptional activity with either ERalpha and ERbeta in transiently transfected CHO-K1 cells. In contrast, both red wine extracts stimulated ERE-reporter activity in a concentration-dependent manner that was inhibited by 4-hydroxytamoxifen (4-OHT), indicating that the observed transcriptional activity was ER-mediated. The red wine extracts showed significantly higher ERbeta versus ERalpha agonist activity. Resveratrol showed no agonist activity in YES but activated ERalpha and ERbeta in CHO-K1 cells in a concentration-dependent manner that was inhibited by 4-OHT. This indicates that resveratrol requires mammalian cell components that are absent in yeast for estrogen agonist activity, whereas the estrogenic activity of wine extracts is directly through ERalpha and does not require mammalian cell factors such as coactivators. The estrogenic activity in red wine found by using YES indicates that estrogenic compounds other than resveratrol are present. Chemical analysis clearly showed that the trans-resveratrol content of the red wine extracts was 1 order of magnitude below the detection limit for YES assay.