Fábio Clasen Chaves

Mycotoxin and fungicide residues in wheat grains from fungicide-treated plants measured by a validated LC-MS method☆

Wheat (Triticum aestivum) is an annual crop, cultivated in the winter and spring and susceptible to several pathogens, especially fungi, which are managed with fungicides. It is also one of the most consumed cereals, and can be contaminated by mycotoxins and fungicides. The objective of this study was to validate an analytical method by LC-MS for simultaneous determination of mycotoxins and fungicide residues in wheat grains susceptible to fusarium head blight treated with fungicides, and to evaluate the relationship between fungicide application and mycotoxin production. All parameters of the validated analytical method were within AOAC and ANVISA limits. Deoxynivalenol was the prevalent mycotoxin in wheat grain and epoxiconazole was the fungicide residue found in the highest concentration. All fungicidal treatments induced an increase in AFB2 production when compared to the control (without application). AFB1 and deoxynivalenol, on the contrary, were reduced in all fungicide treatments compared to the control.

Bioactive and yield potential of jelly palms (Butia odorata Barb. Rodr.)

In this descriptive study, Butia odorata genotypes were evaluated for yield, fruit number, pulp yield, bioactive content (including phenolic compounds, carotenoid, anthocyanin, L-ascorbic acid, and fibre content), antioxidant potential, and phenotypic characteristics. Genotype 117 was the highest yielding, with an estimated fruit yield of 22,000 kg ha(-1) and pulp yield of 12,000 kg ha(-1). On the other hand, the lowest yielding genotype, accession 49, showed an estimated fruit yield of 8400 kg ha(-1). Jelly palm fruit were generally rich in phenolic content (280.50-398.50 mg 100(-1)g), carotenoid content (2.80-4.08 mg 100 g(-1)), and L-ascorbic acid content (34.63-63.84 mg 100g(-1)). While the highest yielding genotype was not the richest in bioactive content, the lowest yielding genotype showed the highest l-ascorbic acid content. Although fruit yield and phytochemical composition are desirable attributes in jelly palm fruit, none of the genotypes evaluated showed high levels of both. Therefore, fruit yield and bioactive phytochemical content appear to be inversely proportional.

Optimized Camellia sinensis var . sinensis , Ilex paraguariensis , and Aspalathus linearis blend presents high antioxidant and antiproliferative activities in a beverage model

A statistical optimization study was conducted to obtain a tea containing fermented rooibos (Aspalathus linearis), white tea (Camellia sinensis var. sinensis), and roasted mate (Ilex paraguariensis). An optimal combination of these species was proposed. This optimized tea inhibited 64% the lipoperoxidation in vitro and presented a high phenolic content, especially kaempferol, (+)-catechin, (-)-epicatechin, rutin, (-)-epigallocatechin, and (-)-epicatechin-2-O-gallate. Indeed, the antioxidant effect was confirmed by decreasing 30% the reactive oxygen species generation in human hepatoma carcinoma cells (HepG2, 100 and 240 µg/mL). In the cell viability assay, the GI50 for human colorectal adenocarcinoma epithelial cells (Caco-2) was about 547 µg/mL and 481 µg/mL for HepG2. The pasteurization process (65 °C/30 min) did not affect the total phenolic content and antioxidant activity of the optimized tea formulation. The sensory test indicated an acceptability index of 78%, showing that the analytical approach adopted was feasible to develop a phenolic-rich beverage.

Preharvest UV-C radiation influences physiological, biochemical, and transcriptional changes in strawberry cv. Camarosa

Ultraviolet C (UV-C) radiation is known for preventing fungal decay and enhancing phytochemical content in fruit when applied postharvest. However, limited knowledge is available regarding fruit responses to preharvest application of UV-C radiation. Thus, the effects of UV-C radiation on photosynthetic efficiency, dry matter accumulation and partitioning, fruit yield and decay, phytochemical content, and relative transcript accumulation of genes associated with these metabolic pathways were monitored in strawberry (Fragaria x ananassa Duch.) cv. Camarosa. A reduction in photosynthetic efficiency was followed by a decrease in light harvesting complex LhcIIb-1 mRNA accumulation as well as a decrease in yield per plant. Phenylalanine ammonia lyase activity, phenolic, anthocyanin, and L-ascorbic acid contents were higher in UV-C treated fruit. In addition, preharvest UV-C treatment reduced microorganism incidence in the greenhouse and on the fruit surface, increased the accumulation of β-1,3-Gluc and PR-1 mRNA, and prevented fruit decay.

Effects of pre-harvest gibberellic acid spraying on gene transcript accumulation during peach fruit development

In order to understand early molecular events associated with increase in fruit size and woolliness prevention induced by pre-harvest gibberellic acid (GA3) spraying, differential transcript accumulation of genes encoding proteins putatively involved in protein folding and protection, cell wall metabolism, and endomembrane transport was studied during fruit development of ‘Chiripá’ peach. Woolliness occurrence reached 100% in untreated peach, was reduced by 15% with GA3 spraying at the end of the pit hardening stage and was significantly reduced (by 78%) in peaches treated at the beginning of the pit hardening stage despite a significantly increased fruit size. Low incidence of woolliness after cold storage and fruit size increase in early GA3 treated peach was correlated with high transcript accumulation of genes encoding proteins putatively involved in protein folding, and protection of the endoplasmic reticulum (heat shock proteins—HSP40 er) and chloroplast (HSP17.8 ch), endomembrane transport (GTPase), as well as genes involved in cell wall loosening (expansins—Exp1, Exp2, Exp3, Exp4).

Liquid Chromatography with mass spectrometry analysis of mycotoxins in food samples using silica hydride based stationary phases

Liquid chromatography with mass spectrometry analysis of selected food samples using silica hydride stationary phases allowed for the identification and quantification of common mycotoxins including aflatoxin B1, B2, G1, G2, ochratoxin A, and fumosinin B1. Phenyl and C18 columns showed relatively similar selectivity based on hydrophobicity but the phenyl phase provides an additional mechanism, π-π interaction. The most hydrophobic of the analyzed compounds was more strongly retained on the C18 column and also has fewer unsaturated sites, which limited the interaction with the phenyl phase. Bean, maize, rice, and wheat samples were harvested and stored under conditions conducive to fungal development, and all samples presented toxin contamination exceeding the maximum tolerable limits.

Transcriptional regulatory networks controlling woolliness in peach in response to preharvest gibberellin application and cold storage

BackgroundPostharvest fruit conservation relies on low temperatures and manipulations of hormone metabolism to maintain sensory properties. Peaches are susceptible to chilling injuries, such as ‘woolliness’ that is caused by juice loss leading to a ‘wooly’ fruit texture. Application of gibberellic acid at the initial stages of pit hardening impairs woolliness incidence, however the mechanisms controlling the response remain unknown. We have employed genome wide transcriptional profiling to investigate the effects of gibberellic acid application and cold storage on harvested peaches.ResultsApproximately half of the investigated genes exhibited significant differential expression in response to the treatments. Cellular and developmental process gene ontologies were overrepresented among the differentially regulated genes, whereas sequences in cell death and immune response categories were underrepresented. Gene set enrichment demonstrated a predominant role of cold storage in repressing the transcription of genes associated to cell wall metabolism. In contrast, genes involved in hormone responses exhibited a more complex transcriptional response, indicating an extensive network of crosstalk between hormone signaling and low temperatures. Time course transcriptional analyses demonstrate the large contribution of gene expression regulation on the biochemical changes leading to woolliness in peach.ConclusionOverall, our results provide insights on the mechanisms controlling the complex phenotypes associated to postharvest textural changes in peach and suggest that hormone mediated reprogramming previous to pit hardening affects the onset of chilling injuries.

Extraction and Quantification of Abscisic Acid and Derivatives in Strawberry by LC-MS

Phytohormones are important plant components that are involved in a signaling cascade in plant development. In strawberry, the influence of abscisic acid (ABA) and its different forms [phaseic acid (PA), dihydrophaseic acid (DPA), and ABA glucose ester (ABA-GE)] on the process of fruit maturation is not yet completely understood. Quantification of phytohormones is currently performed by liquid chromatography coupled to mass spectrometry (LC-MS) due to its sensitivity and specificity. However, the sample matrix and the extraction procedure will influence the analysis. Thus, this study aimed to optimize a simple extraction method and validate the LC-MS quantification of ABA as well as the identification and quantification of ABA derivatives (PA, DPA, and ABA-GE) in strawberry fruit. Hormone extraction was performed using either methanol (80% v/v—S1) or acetone:water:acetic acid (80:19:1 v/v—S2) solutions with or without the use of sonication. The most efficient extraction was obtained using S1 without sonication, and LC-MS validation parameters for ABA were within acceptable scores.

Stability of bioactive compounds in butiá (Butia odorata) fruit pulp and nectar

Butia odorata is a palm tree native to southern Brazil whose fruit (known as butiá) and leaves are used to make many food products and crafts. Butiá contain several biologically active compounds with potential health benefits. However, processing conditions can alter quality attributes including bioactive compound content. This study evaluated the stability of bioactive compounds in butiá pulp upon pasteurization, during 12months of frozen storage, and in butiá nectar after a 3-month storage period. Pulp pasteurization resulted in a reduction in phenolic, flavonoid, carotenoid, and ascorbic acid contents. After a 12-month frozen storage period, flavonoid, phenolic, and ascorbic acid contents decreased while carotenoid content remained unaltered. Carotenoid, ascorbic acid, and phenolic contents were unaffected by the 3-month storage of butiá nectar; however, flavonoid content and antioxidant potential were reduced. Despite bioactive compound degradation upon heat treatment and storage, butiá nectar remained rich in phenolics, especially (-)-epicatechin, rutin, and (+)-catechin.

Cooking quality properties and free and bound phenolics content of brown, black, and red rice grains stored at different temperatures for six months

The changes in cooking quality and phenolic composition of whole black and red rice grains stored during six months at different temperatures were evaluated. Brown rice with known cooking quality properties and low phenolic levels was used for purposes comparison. All rice genotypes were stored at 13% moisture content at temperatures of 16, 24, 32, and 40°C. Cooking time, hardness, free and bound phenolics, anthocyanins, proanthocyanidins, and free radical scavenging capacity were analysed. The traditional rice with brown pericarp exhibited an increase in cooking time and free phenolics content, while rice with black pericarp exhibited a reduction in cooking time after six months of storage at the highest studied temperature of 40°C. There as increases in ferulic acid levels occurred as a function of storage temperature. Red pericarp rice grains showed decreased antioxidant capacity against ABTS radical for the soluble phenolic fraction with increased time and storage temperature.