Dosagem de açúcares redutores com o reativo DNS em microplaca

Systematic Chemical Analysis of Crude Glycan Isolates from the Seven-Herb Decoction Quanzhenyiqitang with Anti-COPD Activity

The classical Chinese Medicine prescription, Quanzhenyiqitang (QZYQT), containing seven tonic herbs (Shudi, Dangshen, Maidong, Baizhu, Niuxi, Fuzi, and Wuweizi) is clinically used to treat chronic obstructive pulmonary disease (COPD). Although there are studies on the pharmacological effects of QZYQT, little attention has been paid to its active carbohydrate ingredients. We performed a systematic chemical analysis of the crude glycan isolates from the seven-herb decoction (GI-QZYQT) after confirming its anti-COPD activity. GI-QZYQT could enhance lung function, reduce lung damage, and alleviate inflammatory response in mice with COPD. Moreover, two monosaccharides (fructose and glucose) and six oligosaccharides (sucrose, melibiose, 1-kestose, raffinose, mannotriose, and stachyose), accounting for 40.23 % of GI-QZYQT, were discovered using hydrophilic interaction liquid chromatography-evaporative light-scattering detection. Inulin-type fructan with an average molecular weight of 2112 Da was identified using high-performance gel-permeation chromatography in combination with monosaccharide mapping analysis, accounting for 20.10 % of GI-QZYQT in mass. The comparison study showed that the identified monosaccharides, oligosaccharides, and the inulin-type fructan of GI-QZYQT were mainly derived from herbs of Shudi, Dangshen, Maidong, Baizhu, and Niuxi. These findings provide crucial information on the chemical composition of GI-QZYQT, which is vital for the in-depth understanding of its bioactivity, mechanism, and product development.

A novel approach for lactose determination in cow's milk exploiting smartphone-based digital-image photometry

Lactose, the main carbohydrate in cow's milk, may cause health problems for consumers with intolerance. Lactose determination in milk is hindered by the matrix complexity and lack of chromophore groups. Chromatography, volumetric, and spectrophotometric approaches involving chemical derivatization are time-consuming and require laborious sample preparation, which is incompatible with the high analytical demand. In this context, a novel approach is presented for lactose determination in milk exploiting smartphone-based digital-image photometry. It was based on a modification of the Benedict's method, involving formation of the violet Cu(I)/2,2'-biquinoline-4,4'-dicarboxylate (BCA) complex instead of the copper(I) oxide precipitate, aiming at improvement of sensitivity and precision. Sample pretreatment and analyte derivatization were performed in Eppendorf tubes with minimal reagent amounts and a smartphone camera was used for image acquisition under controlled conditions. Measurements were based on the RGB color system, taking channel G as the analytical response because of the complementarity with the color of the complex. Under the optimized conditions, the proposed procedure yielded a linear response up to 20 mg L-1 (r = 0.999), with a limit of detection of 1.5 mg L-1, which is compatible with determination of lactose in milk and dairy products categorized with low content of the sugar. The procedure takes less than 10 min, with a coefficient of variation of 3.0% (n = 12) and consumes as low as 160 μg Cu and 430 μg BCA per determination, thus being a more practical, fast, cost-effective, and environmental friendly analytical method.

Transcriptomic Analysis and the Effect of Maturity Stage on Fruit Quality Reveal the Importance of the L-Galactose Pathway in the Ascorbate Biosynthesis of Hardy Kiwifruit (Actinidia arguta)

Hardy kiwifruit (Actinidia arguta) has recently become popular in fresh markets due to its edible skin and rich nutritional value. In the present study, different harvest stages of two A. arguta cultivars, 'Issai' and 'Ananasnaya' ("Ana"), were chosen for investigating the effects of maturity on the quality of the fruit. Interestingly, Issai contained 3.34 folds higher ascorbic acid (AsA) content than Ana. The HPLC method was used to determine the AsA content of the two varieties and revealed that Issai had the higher content of AsA and DHA. Moreover, RNA sequencing (RNAseq) of the transcriptome-based expression analysis showed that 30 differential genes for ascorbate metabolic pathways were screened in Issai compared to Ana, which had 16 genes down-regulated and 14 genes up-regulated, while compared to the up-regulation of 8 transcripts encoding the key enzymes involved in the L-galactose biosynthesis pathway. Our results suggested that AsA was synthesized mainly through the L-galactose pathway in hardy kiwifruit.

Vinegar production from <i>Theobroma grandiflorum</i> SCHUM (cupuassu)

<abstract> <p>The tropical fruit cupuassu comes from <italic>Theobroma grandiflorum</italic> (SCHUM), a close relative of cocoa. Cupuassu has a rich yet delicate flavour profile with notes of chocolate, pineapple, passion fruit and other fruits. Here, we produced a cupuassu-fruit wine using a <italic>Saccharomyces cerevisiae</italic> inoculum (and univariate analysis to determine conditions for optimum ethanol production) and then fermented this wine to produce a delicate and unique cupuassu vinegar using acid-acid bacteria. The cupuassu wine was produced by fermentation of juice chaptalized with sucrose, with a final ethanol concentration of 10% (v/v). Acetic-acid fermentations were carried out in both a bubble-column reactor and a mechanically non-aerated reactor (high-surface reactor), producing final concentrations of 4.5 and 3.3% (w/v) acetic acid, respectively. The ethanol- and acetic-acid yields obtained were comparable to those of other fruit wines and fruit vinegars. The cupuassu vinegar retained the rich flavor profile of the cupuassu. We believe that the production of flavorsome products from local plants can have benefits for conservation by promoting ecologically sustainable agriculture and may contribute to cultural identity of Amazon people.</p> </abstract>

Selection of low nitrogen demand yeast strains and their impact on the physicochemical and volatile composition of mead

Mead is an ancient alcoholic beverage produced through the fermentation of a diluted solution of honey. Due to the peculiar and varied composition of honey, mead production faces several problems, such as slow or stuck fermentations mainly due to the low nitrogen concentration, lack of uniformity of the final product and the production of unpleasant aromas. In this context, this work aimed to select low nitrogen-demand yeast strains and evaluate their potential for the production of mead. Therefore, among 21 commercial wine yeast strains, 5 were selected based on their fermentative behavior at low assimilable nitrogen concentrations. The selected strains were further evaluated for their contributions in meads produced with limited nitrogen availability, and the results showed significant differences on some physicochemical parameters like biomass production, residual sugars, glycerol concentration, and fermentative rate. Moreover, meads obtained with selected strains differed in the concentration of several volatile compounds. The volatile compounds concentration and the principal component analysis based on odor activity values allowed separating strains into three groups. In general, S. cerevisiae var bayanus strains (QA23, Spark, and AWRI-R2) were the largest producers of aromatic compounds, particularly those with floral and fruity descriptors. The selection of yeast strains with low nitrogen-demand and different volatile compounds production can be explored by mead makers to limit fermentation problems and obtain characteristic products.

Update and Revalidation of Ghose's Cellulase Assay Methodology

New studies on cellulolytic enzymes aiming to improve biofuels production lead to a concern over the assaying methods commonly applied to measure their activity. One of the most used methods is Ghose's cellulase and endoglucanase assay, developed by the International Union of Pure and Applied Chemistry in 1987. Carrying out this method demands high volumes of reagents and generation of high amounts of chemical residues. This work aimed to adapt Ghose's methodology to reduce its application cost and residue generation and validate the adjustments. To do so, International and Brazilian laws were applied to validate methodologies. Method's modifications were successfully validated according to all institutions and were considered linear, accurate, precise, and reproducible. It was possible to reduce the volume of reagents and residues in 12 times. Considering the routine work of most laboratories, it is a great reduction on material costs and residue treatment, which reflects in sustainability and environmental impacts.

Effect of Cadmium Accumulation on the Performance of Plants and of Herbivores That Cope Differently With Organic Defenses

Some plants are able to accumulate in their shoots metals at levels that are toxic to most other organisms. This ability may serve as a defence against herbivores. Therefore, both metal-based and organic defences may affect herbivores. However, how metal accumulation affects the interaction between herbivores and organic plant defences remains overlooked. To fill this gap, we studied the interactions between tomato (Solanum lycopersicum), a model plant that accumulates cadmium, and two spider-mite species, Tetranychus urticae and Tetranychus evansi that, respectively, induce and suppress organic plant defences, measurable via the activity of trypsin inhibitors. We exposed plants to different concentrations of cadmium and measured its effects on mites and plants. In the plant, despite clear evidence for cadmium accumulation, we did not detect any cadmium effects on traits that reflect the general response of the plant, such as biomass, water content, and carbon/nitrogen ratio. Still, we found effects of cadmium upon the quantity of soluble sugars and on leaf reflectance, where it may indicate structural modifications in the cells. These changes in plant traits affected the performance of spider mites feeding on those plants. Indeed, the oviposition of both spider mite species was higher on plants exposed to low concentrations of cadmium than on control plants, but decreased at concentrations above 0.5 mM. Therefore, herbivores with contrasting responses to organic defences showed a similar hormetic response to metal accumulation by the plants. Additionally, we show that the induction and suppression of plant defences by these spider-mite species was not affected by the amount of cadmium supplied to the plants. Furthermore, the effect of cadmium on the performance of spider mites was not altered by infestation with T. urticae or T. evansi. Together, our results suggest no interaction between cadmium-based and organic plant defences, in our system. This may be useful for plants living in heterogeneous environments, as they may use one or the other defence mechanism, depending on their relative performance in each environment.