Physicochemical properties and biological activities of bracatinga honeydew honey from different geographical locations.

Bracatinga (Mimosa scabrella Bentham) honeydew honey is a Brazilian dark honey in increasing international appreciation. In this sense, the knowledge of its composition and potential biological properties becomes indispensable. In the present study, the physicochemical characteristics, including mineral and phenolic composition, and the scavenging, reducing, and antimicrobial proprieties of bracatinga honeydew honey (bhh) from five different geographical locations, were investigated. Bhh proved to be a potential functional food due to its high content of minerals (up to 6395 mg kg-1) and phenolic compounds (up to 2393 µg 100 g-1) and high scavenging and reducing activities. High antimicrobial activity against four bacterial strains, with minimum inhibitory concentration values ranging from 10 to 60%, were also found. Additionally, through principal component analysis, partial discrimination of bhh was observed according to the geographical location, which favored the separation of samples from Lages, and mainly due to the presence of nectar in this honey, which was proposed for the samples from Bom Retiro. SUPPLEMENTARY INFORMATION: The online version of this article (10.1007/s13197-020-04937-x) contains supplementary material, which is available to authorized users.

Quantification of pyrrolizidine alkaloids in Senecio brasiliensis, beehive pollen, and honey by LC-MS/MS.

This article presents the determination of eight pyrrolizidine alkaloids (PAs) by LC-MS/MS in honeys, pollen, and Senecio brasiliensis (Asteraceae) samples, all from Santa Catarina state, Brazil. In addition, the Box-Behnken design was used to perform an optimized sample preparation on pollens and S. brasiliensis parts. Senecionine and its N-oxide, besides retrorsine N-oxide, were determined in six of the seven honeys samples. Pollen from species of the Asteraceae, Fabaceae, and Boraginaceae families were found with greater predominance in three of the seven honeys samples. In these three honeys samples were also found the highest PAs levels. In beehive pollen, flower, and leaf of S. brasiliensis, the total levels of PAs and their N-oxides reached 221, 14.1 × 104, and 14.8 × 104 mg kg-1, respectively. In honeys, these compounds are chemical contaminants and therefore undesirable when the sum exceeds 71 µg kg-1, according to EFSA. On the other hand, although PAs are naturally present in plant and pollen of some species (Senecio, Crotalaria, Bacharis, Ecchium, Mimosa scabrella, Vernonia), it is important to monitor their levels in plants but also in honeys, and other beehive products since these compounds are transferred to the final product.

Determination of Phenolic Compounds in Three Edible Ripening Stages of Yellow Guava (Psidium cattleianum Sabine) after Acidic Hydrolysis by LC-MS/MS.

Yellow guava (Psidium cattleianum Sabine) has received considerable attention in the last years because of their high content in bioactive compounds with potential application in food and pharmaceutical industries. In this regard, this study aimed to investigate the phenolic compounds of three edible ripening stages of yellow guava fruits after acidic hydrolysis by liquid chromatography-tandem mass spectrometry (LC-MS/MS) and their antioxidant capacity. Among the 23 phenolics quantified, catechin, isoquercitrin, quercetin, gallic acid, and syringic acid showed significant concentrations in all the evaluated stages, with values ranging from 479.59 ± 12.52 to 12,795.50 ± 320.95 µg 100 g-1 of dry matter. In general, higher concentrations of phenolic acids were found in the latter ripening stages, while flavonoids were in the earlier ripening stages. These findings suggest that the ripening process promotes changes in the phenolic composition of yellow guava. However, considering the sum of phenolic compounds and the antioxidant capacity, all ripening stages investigated can be suggested as a supply of bioactive compounds for consumers.

Blackberry (Rubus ulmifolius Schott): Chemical composition, phenolic compounds and antioxidant capacity in two edible stages.

The berries of the genus Rubus has been highlighted as important source of bioactive and health promoting constituents, however, information about chemical composition and antioxidant potential of the specie Rubus ulmifolius are still scarce. In this regard, this study aimed to assess the physicochemical characteristics, total monomeric anthocyanins (TMA), individual phenolics, minerals, sugars, and antioxidant properties of mature and fully mature R. ulmifolius. With the advance of maturation, changes in the physicochemical composition suggest pleasant characteristics for consumption especially in the fully mature stage. High levels of TMA and sugars (fructose and glucose) were also verified in the fully mature stage, as well as, expressive antioxidant potential, with values of 241.06 µM Fe+2 g-1 for ferric reducing antioxidant power and 28.22 mg gallic acid equivalent g-1 for Folin-Ciocalteu reducing capacity (all expressed in dry matter, DM). In contrast, minerals (potassium, calcium, sodium) and most of the studied phenolic compounds showed the highest concentrations in mature fruits. Among the phenolics investigated, 26 compounds were identified and quercetin and isoquercitrin were the predominant phenolic compounds in the fruit. The results reinforce the nutritive and antioxidant potential of Rubus ulmifolius in both maturation stages studied.

Phenolic Compounds Determined by LC-MS/MS and In Vitro Antioxidant Capacity of Brazilian Fruits in Two Edible Ripening Stages.

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.

Nutritional and bioactive potential of Myrtaceae fruits during ripening.

This study aimed to characterize jabuticaba (Myrciaria cauliflora), guabiju (Myrcianthes pungens), and jambolan (Syzygium cumini) in relation to its individual phenolic compounds (LC-ESI-MS/MS), antioxidant capacity, total monomeric anthocyanin, sugars, and minerals during ripening (intermediate and ripe stages). In the three studied fruits, 22 phenolic compounds were quantified, especially phenolic acids and flavonoids, which presented a higher concentration in the intermediate ripening stage. In contrast, the total monomeric anthocyanin, fructose, glucose, Ca, Na values were higher in the ripe stage. In addition, all studied fruits showed expressive antioxidant capacity in both ripening stages: 2569.28 to 5066.35mg AAE 100g-1 DW for DPPH; 13777.52 to 26667.45µmol Fe+2 100g-1 DW for FRAP; and 957.72 to 2061.35mg GAE 100g-1 DW for Folin-Ciocalteu reducing capacity. Therefore, our results revealed that these fruits represent a supply of high-value nutrient and bioactive components, especially in the ripe stage.

Effect of in vitro gastrointestinal digestion on the bioaccessibility of phenolic compounds, minerals, and antioxidant capacity of Mimosa scabrella Bentham honeydew honeys.

Honey is a product traditionally consumed due to its possible health benefits promoted by natural antioxidants. However, few studies have evaluated the effect of in vitro gastrointestinal digestion on these compounds in honeys. To improve the knowledge of this subject, the present study aimed to investigate the influence of simulated digestion on the stability of antioxidant capacity (FRAP, DPPH, and Folin-Ciocalteu assays), phenolic compounds (LC-ESI-MS/MS), and minerals (CE-DAD) in Mimosa scabrella Bentham honeydew honeys. The results show that the digestive system, mainly after duodenal digestion, significantly decreased the antioxidant capacity assessed by FRAP (410.3±18.3 to 564.7±8.4µmolFe+2100g-1), DPPH (30.1±0.8 to 33.9±1.4mgAAE100g-1), and Folin-Ciocalteu assays (58.3±2.6 to 142.0±1.6mgGAE100g-1) of this honey. However, phenolic compounds and minerals showed high stability and in some cases, significantly increased after the simulated digestion, presenting a bioaccessible fraction that ranged from 78.2±6.4 to 174.38±6.82% and 94.0±4.3 to 220.5±3.4%, respectively. Therefore, these honey constituents may be considered highly bioaccessible and potentially bioavailable. Additionally, the correlation between the investigated parameters suggests that other honey constituents could also possibly affect antioxidant capacity of this honey. In conclusion, the bracatinga (Mimosa scabrella Benth.) honeydew honey can be highlighted as an important natural source of bioaccessible polyphenols, besides presenting highly bioaccessible minerals in its composition, maintaining a satisfactory antioxidant capacity.

Development, validation and different approaches for the measurement uncertainty of a multi-class veterinary drugs residues LC-MS method for feeds.

A sensitive method for the simultaneous residues analysis of 62 veterinary drugs in feeds by liquid chromatography-tandem mass spectrometry has been developed and validated in accordance to Commission Decision 657/2002/EC. Additionally, limits of detection (LOD), limits of quantitation (LOQ), matrix effects and measurement uncertainty were also assessed. Extraction was performed for all analytes and respective internal standards in a single step and chromatographic separation was achieved in only 12min. LOQ were set to 0.63-5.00µgkg-1 (amphenicols), 0.63-30.00µgkg-1 (avermectins), 0.63µgkg-1 (benzimidazoles), 0.25-200.00µgkg-1 (coccidiostats), 0.63-200.00µgkg-1 (lincosamides and macrolides), 0.25-5.00µgkg-1 (nitrofurans), 0.63-20.00µgkg-1 (fluoroquinolones and quinolones), 15.00µgkg-1 (quinoxaline), 0.63-7.50µgkg-1 (sulfonamides), 0.63-20.00µgkg-1 (tetracyclines), 0.25µgkg-1 (ß-agonists), and 30.00µgkg-1 (ß-lactams). The top-down approach was adequate for the calculation of measurement uncertainty for all analytes, except the banned substances, which should be rather assessed by the bottom-up approach. Routine analysis of different types of feeds was then carried out. An interesting profile of residues of veterinary drugs among samples was revealed, enlightening the need for stricter control in producing animals. Among the total of 27 feed samples, 20 analytes could be detected/quantified, ranging from trace levels to very high concentrations. A high throughput screening/confirmatory method for the residue analysis of several veterinary drugs in feeds was proposed as a helpful control tool.

Analytical optimization of a phenolic-rich herbal extract and supplementation in fermented milk containing sweet potato pulp.

The aims of the present study were to optimize and characterize the phenolic composition of a herbal extract composed of green mate (Ilex paraguariensis), clove (Syzygium aromaticum), and lemongrass (Cymbopogon citratus) and to propose the addition of this polyphenol-rich extract to fermented milks (FM) with/without sweet potato pulp (Ipomoea batatas). Proximate composition, pH, acidity, instrumental texture profile, total phenolic content (TPC), antioxidant activity (AA) of all formulations were measured, and sensory attributes were also investigated. The addition of a lyophilized extract (1g 100g-1) containing 87.5% clove and 12.5% green mate increased the AA and TPC, while FM with added sweet potato pulp had the best sensory acceptance. The TPC and total reducing capacity had a slight change during 21days of storage. The data showed that herbal extracts and sweet potato pulp may be used to develop new dairy foods with potential functional properties.

Development of a LC-MS/MS method for the simultaneous determination of sorbic acid, natamycin and tylosin in Dulce de leche.

A simple extraction, rapid routine method for the simultaneous determination of sorbic acid, natamycin and tylosin in Dulce de leche, a traditional South American product, by liquid chromatography-tandem mass spectrometry has been developed and fully validated. The limits of detection were set to 24.41mgkg(-1) (sorbic acid), 0.10mgkg(-1) (natamycin) and 2µgkg(-1) (tylosin). Recoveries ranged from 95% to 110%. Proportionally, internal standardization was more efficient than external standard, resulting in a smaller measurement of uncertainty. In total, 35 commercial samples from Brazil, Argentina and Uruguay have been assessed. The proposed method was tested on other dairy desserts, demonstrating to be versatile. Although tylosin was not detected in any sample, a high rate of non-compliance was found, with 67.39% of samples above the maximum allowed for sorbic acid and a maximum concentration of 2105.36±178.60mgkg(-1). In two samples, natamycin was irregularly found.

A sub-minute CZE method to determine nitrate and nitrite in meat products: An alternative for routine analysis.

A sub-minute capillary zone electrophoresis (CZE) method was optimized and a simple sample preparation procedure based on the extraction of the analytes with water and sodium tetraborate was developed for the simultaneous determination of nitrate and nitrite levels in meat products. The background electrolyte (BGE) was composed of 20mmolL(-1) perchloric acid and 65mmolL(-1) ß-alanine at pH3.83. Thiocyanate was used as the internal standard. The proposed method was validated and the uncertainty estimated according to Eurachem guidelines. The run time was only 30s, allowing analyzing more than 25samples/h, the good analytical performance confirms the suitability of the method for the analysis of meat products. One sample presented residual nitrite levels above the limit established by MERCOSUL legislation (150mgkg(-1)). The use of a fast method in association with a simple sample preparation step means that this procedure represents a possible alternative to fulfill the demand for high throughput in routine laboratory analysis.

Development and validation of a LC-ESI-MS/MS method for the determination of phenolic compounds in honeydew honeys with the diluted-and-shoot approach.

A simple, reproducible and sensitive method has been optimized and validated for simultaneous determination of 32 phenolic compounds in bracatinga (Mimosa scabrella Benth.) with the diluted-and-shoot approach, without the need of any additional clean-up steps. It has been based on high performance liquid chromatography coupled with triple quadrupole tandem mass spectrometry and electrospray ionization (HPLC-ESI-MS/MS). The chromatography conditions were optimized, and due to the selectivity provided by MRM monitoring, LC separation required only 9min. The developed method was validated on the basis of Eurachem and European Commission Decision 2002/657/EC guidelines. Mean recoveries ranged from 70.4 to 110%. Intra-day and inter-day precision with RSD (relative standard deviations) from 0.14 to 18.9% and 0.34 to 20.0%, respectively were achieved. Limits of detection (LOD) and quantification (LOQ) ranged from 0.03 to 3.20µgL-1 and 0.20-12.8µgL-1. Finally, the method was applied to samples and 20 phenolic compounds were quantified in all the samples analyzed, representing a contribution to the characterization and quantification of phenolic compounds from bracatinga (M. scabrella Bentham) honeydew honey.

Effects of time and extraction temperature on phenolic composition and functional properties of red rooibos (Aspalathus linearis).

This work was aimed at assessing the time-temperature effects on the phenolic compounds and in vitro functional properties of aqueous extracts from red rooibos (Aspalathus linearis). The major phenolic composition (tannins, flavonoids, flavonols, ortho-diphenols, total phenolic content), antioxidant (ABTS and DPPH) and reducing capacities (FRAP and total reducing capacity), antimicrobial effects and inhibition of α-amylase/α-glucosidase were measured. Phenolic compounds were also determined by LC-ESI-MS/MS. Aqueous extracts did not inhibit the growth of Escherichia coli, Staphylococcus aureus, and Candida albicans between 7.81 and 1000mgL-1. Rooibos extracted at 85°C for 10min showed a beneficial interaction with the human erythrocytes, reducing the hemolysis. The correlation analysis showed that the phenolic compounds responsible for the inhibition of α-amylase (IC50) were isohrmanetin, isoquercitrin, luteolin, salicylic acid, and syringaldehyde, whereas the inhibition of α-glucosidase was correlated to syringaldehyde, isoquercitrin, and luteolin. Overall, rooibos extracted at 85°C had the highest antioxidant activity measured by all assays, higher contents of phenolic compounds (spectrophotometric and LC-ESI-MS/MS data), and lower IC50 values for the digestive enzymes. On the other hand, rooibos extracted at 65°C had the opposite behavior, while rooibos extracted at 75°C presented mean intermediate values for the responses. This result clearly indicates that the extraction temperature is the main factor leading to a higher extraction of bioactive compounds from red rooibos.

A simple and fast method for the inspection of preservatives in cheeses and cream by liquid chromatography- electrospray tandem mass spectrometry.

In this work, a simplified extraction and short time of analysis method for the simultaneous determination of natamycin, nisin and sorbic acid in cheeses and cream by reverse phase liquid chromatography-electrospray-tandem mass spectrometry was developed. Full validation was performed according to the Commission Decision 2002/657/EC criteria and method applicability was checked on several samples, aiming to inspect their compliance with regulatory limits. The method was linear in the concentration ranges of 0-10mg kg(-1) (natamycin), 0-25mg kg(-1) (nisin) and 0 20mg kg(-1) (sorbic acid). Samples of the three most consumed types of cheese (fresh, pasta filata and ripened) in Brazil and cream (ultra high temperature and pasteurized, 20-30% fat content) were assessed. A surprising rate of non-compliance was observed, especially among ripened grated cheeses, since 80% of samples were above the maximum limit for sorbic acid with an average concentration of 2766.3±10.8mg kg(-1). Moreover, a major non-compliance for the cream samples was observed. The proposed method can be applied as an efficient tool for the inspection of preservatives in cheeses and cream.

A Rapid Method for Analysis of Phenylalanine in Cereal Products by MEKC-UV Using LC/MS/MS as a Comparative Method.

The aim of this study was to develop a new and fast micellar electrokinetic chromatography (MEKC) method for the determination of phenylalanine in cereal samples. The background electrolyte was chosen by a factorial design and was composed of 30 mmol/L phosphoric acid, 100 mmol/L sodium dodecyl sulfate, and 25% methanol (v/v) at pH 1.9. A fused silica capillary (48.5 cm total length×8.5 cm effective length×50 µm id×375 µm od) was used in a short-end injection configuration, and direct UV detection was at 200 nm. The method was validated following the Eurachem guidelines, and values such as linearity (from 10.1 to 40.4 mg/L); recovery (86.8-103.9%); repeatability (0.06-0.22% for migration time and 1.14-4.82% for peak area); reproducibility (0.04-0.61% for migration time and 2.22-5.72% for peak area); and LOD and LOQ of 20 and 60 mg/100 g, respectively, were obtained. After the comparison involving selectivity and accuracy between capillary electrophoresis and LC/MS/MS method, the MEKC-UV method was successfully applied to analysis of phenylalanine in different cereal products.

Development of a fast and selective separation method to determine histamine in tuna fish samples using capillary zone electrophoresis.

This paper reports on the development of a fast and selective separation method by capillary zone electrophoresis (CZE) for the determination of histamine in tuna fish samples. The background electrolyte was composed of 60 mmol L(-1) hydroxyisobutyric acid and 10 mmol L(-1) sodium hydroxide at pH 3.3. The internal standard used was imidazole. Separations were performed in a fused uncoated silica capillary (32 cm total length, 8.5 cm effective length and 50 µm internal diameter) with direct UV detection at 210 nm. The samples and standards were injected hydrodynamically (50 mbar, 3s) from the outlet capillary end (nearest to the detector) and the electrophoretic system was operated under normal polarity and constant voltage conditions of 30 kV (positive polarity on the injection side). The migration time of histamine in the proposed method was only 0.34 min. The method was then validated and different tuna fish samples were analyzed. Good linearity (R(2)>0.999), a limit of detection 0.14 mg L(-1), intra-day precision better than 3.5% (peak area of sample), and recovery in the range of 94-108% were obtained. The results of the histamine concentration determined in the samples by the CZE method were compared with the LC-MS/MS method.