This paper proposes an innovative sub-minute capillary zone electrophoresis method and a simple sample preparation procedure for simultaneous nitrate and nitrite determination. The novelty of the ...method is the simplicity of execution and the capacity to separate the analytes in less than 0.5min. The BGE is composed of 10mmolL−1 perchloric acid and 40mmolL−1 β-alanine at pH 3.96. Thiocyanate was used as an internal standard. The method was validated following the Eurachem guidelines and applied to the analysis of 14 baby food samples. Of these samples, one had nitrate levels above that permitted by Brazilian legislation (250mgkg−1) and for all samples the nitrite concentrations were under the limit of quantification. The good analytical performance verified for this method indicates that it is suitable for implementation in food laboratories for the routine determination of nitrate and nitrite as an alternative to the official method provided by the AOAC.
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•A sub-minute CZE method was developed for the determination of nitrate and nitrite.•The CZE method was applied in the analysis of baby foods.•Sample preparation step was simple and effective to extract the analytes.•Analytical validation was performed according to the Eurachem guidelines.•The CZE method showed good analytical performance to the analysis of baby foods.
The phenolic compounds content and antioxidant activity of seed and skin of pomace from the vinification of grape varieties widely produced in Brazil were investigated with a view to their ...exploitation as a potential source of natural antioxidants. There was a greater concentration of phenolic compounds in the seeds (2128 to 16,518
mg of catechin equivalents (CE)/100
g) than in the skins (660 to 1839
mg CE/100
g). The highest antioxidant activity values determined as DPPH radical-scavenging ability and ferric reducing-antioxidant power (FRAP) were found for the seeds of the Pinot Noir variety (16,925
μmol Trolox equivalents (TE)/100
g and 21,492
μmol Fe
2+/100
g, respectively) and in the skin extracts of the Isabel variety (3640
μmol TE/100
g and 4362
μmol Fe
2+/100
g, respectively). The skin of Cabernet Sauvignon and Primitivo varieties had the highest contents of anthocyanins (935 and 832
mg/100
g, respectively). The grape seed extracts were rich in oligomeric and polymeric flavanols. The data suggested that grape seed and skin extracts may be exploited as antioxidant agents.
•Study of the effects of thermal treatment on the formation of 5-HMF and sugars.•Thermal treatment was optimised using full factorial design 22 with central point.•Intralaboratory analytical method ...validation was performed according Eurachem.•Results suggest a possible resistance to 5-HMF formation in stingless bee honey.
This study aimed to assess 5-hydroximethylfurfural and carbohydrates (fructose, glucose, and sucrose) in 13 stingless bee honey samples before and after thermal treatment using a capillary electrophoresis method. The methods were validated for the parameters of linearity, matrix effects, precision, and accuracy. A factorial design was implemented to determine optimal thermal treatment conditions and then verify the postprocedural 5-HMF formation, but once 5-HMF were <LOQ was not possible to build a response surface. The methods applied to samples obtained from Brazil, expressed good linearity, precision, and accuracy. None of the thirteen in natura samples presented 5-HMF, and carbohydrate levels ranged from 48.59% to 69.36%. In the same conditions of thermal treatment, Apis mellifera honey presented higher 5-HMF content than stingless bee honey. Results suggest that a high temperature related to briefer thermal treatment could be an efficient way to extend shelf life without affecting 5-HMF content in stingless bee honey.
This study was performed with floral honeys from an innovator and pioneer project in Brazil for the digital monitoring of beehives. Samples from six regions of the Santa Catarina state were evaluated ...for moisture, acidity, pH, electrical conductivity, 5-HMF, diastase activity, fructose, glucose, sucrose, and minerals (K, Ca, Na, Mg, and Mn). Furthermore, chemometric analyzes were applied to classify honeys based on these parameters. Some results did not corroborate with the current legislation for free acidity (≤ 50 mEq kg
−1
) and electrical conductivity (≤ 0.8 mS cm
−1
). In all samples, the minerals K (0.37 × 10
3
to 3.03 × 10
3
mg kg
−1
) and Ca (0.03 × 10
3
to 0.38 × 10
3
mg kg
−1
) were majority. Considering that the results were different (
p
< 0.05) for all floral honey samples, cluster and principal components analysis (PCA) were performed to group samples by similarity. Cluster analysis provided a first separation of the honeys and PCA highlighted the K, Ca, Mg, and Na as the best contributors for honeys discrimination. In this regard, the physicochemical parameters, sugar, and mineral content were important to elucidate the characteristics of honeys. They indicated that the beehives handling and the hygienic-sanitary conditions during the collection and transport of samples were also adequate. Furthermore, mineral elements were proposed to discriminate honey samples produced in different regions of Santa Catarina state, Brazil.
Anthocyanins belong to a large group of secondary plant metabolites collectively known as flavonoids, a subclass of the polyphenol family. They are a group of very efficient bioactive compounds that ...are widely distributed in plant food. Anthocyanins occur in all plant tissues, including leaves, stems, roots, flowers, and fruits. Research on phenolic compounds through the last century, from the chemical, biochemical, and biological points of view, has focused mainly on the anthocyanins. Anthocyanins have structures consisting of two aromatic rings linked by three carbons in an oxygenated heterocycle (i.e., a chromane ring bearing a second aromatic ring in position 2). The basic chromophore of anthocyanins is the 7-hydroxyflavilyum ion. Anthocyanin pigments consist of two or three chemical units: an aglycon base or flavylium ring (anthocyanidin), sugars, and possibly acylating groups. Only six of the different anthocyanidins found in nature occur frequently and are of dietary importance: cyanidin, delphinidin, petunidin, peonidin, pelargonidin, and malvidin. Each aglycon may be glycosilated or acylated by different sugars and aromatic or aliphatic acids, yielding over 600 different anthocyanins reported from plants. The sugar moiety is typically attached at the 3-position on the C-ring or the 5-position on the A-ring. The chromophore of eight conjugate double bonds carrying a positive charge on the heterocyclic oxygen ring is responsible for the intensive red-orange to blue-violet color produced by anthocyanins under acidic conditions. Anthocyanins occur in solution as a mixture of different secondary structures: flavylium ion, a quinoidal base, a carbinol base, and a chalcone pseudobase. Self-association, intermolecular, and intramolecular co-pigmentation of anthocyanins leads to the formation of tertiary structures through varying stabilization mechanisms. Anthocyanin composition has been used as a botanical tool for taxonomic classification of plants. In addition, anthocyanin profiles of fruits and vegetables allow detecting adulteration of anthocyanin-based products and are indicators of product quality. Anthocyanins are common components of the human diet, as they are present in many foods, fruits, and vegetables, especially in berries. Moreover, anthocyanins have an antioxidant activity, depending to a large extent upon their chemical structure. Many epidemiological studies have shown the benefits of a diet rich in fruit and vegetables to human health, and for the prevention of various diseases associated with oxidative stress, such as cancer and cardiovascular diseases. Anthocyanin-rich extracts are increasingly attractive to the food industry as natural alternatives to synthetic FD&C dyes and lakes, because of their coloring properties. Anthocyanins are also one of the nine European Union-designated natural color classes. Various adverse effects on health have frequently been attributed to synthetic antioxidants. For these reasons, currently, there is a trend towards relying on antioxidants derived from natural products. Anthocyanins act as antioxidants both in the foodstuffs in which they are found and in the organism after intake of these foods. This review, like the first one of the series, intends to reflect the interdisciplinary nature of the research that is currently carried out in this prolific area.
Ripening and growing location are important factors that can impact fruit quality characteristics. In this study, the influence of these factors on physicochemical characteristics, carbohydrates, ...aliphatic organic acids, phenolic compounds, and antioxidant capacity of red guava (
Psidium cattleianum
Sabine) was evaluated. Fruit ripening increased fructose and glucose (up to 22.83 and 16.42 g 100 g
− 1
dry matter (DM), respectively), and decreased citric acid, the major organic acid (up to 135.35 mg g
− 1
DM). Ripening and growing location also influenced the concentration of phenolic compounds and antioxidant capacity of red guava, in which a dependency between both factors was observed in most cases. Apigenin, galangin, isoquercitrin, among other phenolic compounds were quantified for the first time in red guava, in which isoquercitrin was the major (up to 13409.81 mg kg
− 1
DM). The antioxidant potential of red guava was also confirmed by ferric reducing antioxidant power assay (up to 82.63 µmol Fe
+ 2
g
− 1
DM), Folin-Ciocalteu reducing capacity assay (up to 17.79 mg gallic acid equivalent g
− 1
DM), and DPPH free radical scavenging assay (up to 25.36 mg ascorbic acid equivalent g
− 1
DM). These results especially demonstrated the bioactive potential of red guava and provided knowledge regarding the influence of ripening and growing location on chemical and bioactive components encouraging its industrial exploitation.
Honeydew honeys, including bracatinga (
Mimosa scabrella
Bentham) honeydew honey, are highly appreciated due to its nutritional and sensory properties. Therefore, fast and inexpensive methods must be ...developed to differentiate this distinct class of honey. Although methods using the visible spectrophotometric fingerprint (VSF) have never been used to differentiate bracatinga honeydew honey and blossom honey, this technique appears to be a viable alternative, successfully used in the differentiation and fraud detection of various foods, including honeys from other botanical sources. In this sense, the present study aimed to verify the existence of a specific VSF for bracatinga honeydew honey and blossom honey and differentiate both type of honeys using the VSF associated with chemometric analysis. The VSF of 30 bracatinga honeydew honeys harvested in three different years (2014, 2016, and 2018) and 21 blossom honeys (harvested in 2016) were evaluated. The existence of a different VSF for bracatinga honeydew honeys and blossom honeys allowed the satisfactory differentiation of both types of honeys. Additionally, bracatinga honeydew honey presented a unique VSF, independent of the year of harvest, which can be exploited as a fingerprint of this type of honey, contributing to its authenticity.
Bracatinga (
Mimosa scabrella
Bentham) honeydew honey (BHH) is a peculiar Brazilian honey. It is produced only every 2 years, which raises concerns about its quality since it can be submitted to ...different storage conditions until a new harvest is carried out. Therefore, this study investigated the changes in the visible spectrophotometric profile (VSP) of BHH during its storage at room temperature over 24 months and 40 °C for 4 months. Our findings indicated a similar VSP between the BHH samples, but that varied according to the storage condition. These changes were associated with the formation of brown compounds, such as 5-hydroxymethylfurfural, which has a maximum limit established for honeys. Thereby, absorbance above 0.500 absorption units between 380 and 410 nm was proposed as indicative of BHH exposure to prolonged heating with significant loss of its quality. Still, a regression model for absorbance at 380 nm was proposed aiming to predict the BHH storage time at room temperature, since storage time longer than 20 months at average temperatures of 23.0 ± 2.3 °C do not seem to be suitable for BHH. Thus, the VSP showed potential for monitoring BHH quality.
The aim of this study was to investigate the free individual phenolics and the
in vitro
antioxidant capacity of blackberry, acerola, yellow guava, guabiju, jambolan and jabuticaba fruits in two ...edible stages. Of the thirty-three phenolics investigated by liquid chromatography - tandem mass spectrometry (LC-MS/MS), twenty-five were quantified and the major ones were catechin, isoquercitrin, epicatechin and gallic acid. The highest values for the total phenolic content (in dry matter) were observed for acerola (83.6 to 97.7 mg gallic acid equivalents g
−1
DM) and blackberry (18.9 to 28.3 mg gallic acid equivalents g
−1
DM); however, acerola, jabuticaba, and blackberry showed the highest antioxidant capacities (134.6 to 1120.4 mg Trolox equivalents g
−1
for 2,2-diphenyl-1-picrylhydrazyl and 43.6 to 501.8 μmol Trolox equivalents g
−1
for ferric reducing antioxidant power). For most fruits, the antioxidant capacity decreased during the ripening, possibly due to a decrease in the concentration of most of the phenolics.
The juçara palm tree produces a small spherical and black-purple fruit similar to açaí. It is rich in phenolic compounds, especially anthocyanins. A clinical trial evaluated the absorption and ...excretion of the main bioactive compounds in urine and the antioxidant capacity in serum and erythrocytes of 10 healthy subjects after juçara juice intake. Blood samples were collected before (0.0 h) and 0.5 h, 1 h, 2 h, and 4 h after a single dose (400 mL) of juçara juice, while urine was collected at baseline and 0-3 and 3-6 h after juice intake. Seven phenolic acids and conjugated phenolic acids were identified in urine deriving from the degradation of anthocyanins: protocatechuic acid, vanillic acid, vanillic acid glucuronide, hippuric acid, hydroxybenzoic acid, hydroxyphenylacetic acid, and ferulic acid derivative. In addition, kaempferol glucuronide was also found in urine as a metabolite of the parent compound in juçara juice. Juçara juice caused a decrease in the total oxidant status of serum after 0.5 h in comparison to baseline values (
< 0.05) and increased the phenolic acid metabolites excretion. This study shows the relationship between the production of metabolites of juçara juice and the total antioxidant status in human serum, indicating evidence of its antioxidant capacity.
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