Bioactive compounds of honey from different regions of Brazil: the effect of simulated gastrointestinal digestion on antioxidant and antimicrobial properties.

Monofloral and multifloral honey produced in different regions may have different bioactive compounds and antioxidant capacities, resulting in changes in the antimicrobial activity of honey. However, many of these compounds degrade due to the extreme digestion conditions, which may inhibit the antimicrobial activity. Given this context, this study aimed to describe the bioactive compounds of honey produced in Brazil and verify if honey samples from different botanical and geographical origins differ in bioactive compounds, and if honey maintains its antimicrobial activity after digestion simulation. Multivariate analysis was used to identify characteristics that differentiated the honey samples according to the botanical and geographical origin criteria. The amount of the bioactive compounds varied significantly: the total phenolic compound content varied from 20.49 to 101.44 mg GAE per 100 g, flavonoids varied from 1.41 to 13.52 mg QE per 100 g, phenolic acids varied from 13.61 to 56.41 mg CAE per 100 g, and carotenoids varied from 0.66 to 4.27 mg ß-carotene per g. Multifloral honey (H22) produced in the dry season of northeastern Brazil presented the highest bioactive compound concentration except for the carotenoid content. HPLC-MS analysis showed the presence of six hydroxybenzoic acids, four hydroxycinnamic acids, eight flavonols, three flavanones, two flavones and two isoflavonoids; Pterodon pubescens monofloral honey (H14) from midwestern Brazil stood out in terms of the carotenoid content. All analyzed honey samples exhibited antimicrobial activity against Staphylococcus aureus and Escherichia coli bacteria before digestive process simulation, and bacteria were inhibited during in vitro digestion; this activity decreased during the simulation of the oral phase, remained in the gastric phase, and disappeared in the intestinal phase.

Bioactive compounds of pequi pulp and oil extracts modulate antioxidant activity and antiproliferative activity in cocultured blood mononuclear cells and breast cancer cells.

BACKGROUND: Pequi (Caryocar brasiliense Camb.) is a fruit from Brazilian Cerrado rich in bioactive compounds, such as phytosterols and tocopherols, which can modulate the death of cancer cells. OBJECTIVE: In the present study, the main bioactive compounds of hydrophilic and lipophilic extracts of pequi oil and pulp were identified and were verified if they exert modulatory effects on oxidative stress of mononuclear cells cocultured with MCF-7 breast cancer cells. STUDY DESIGN: Identification and quantification of the main compounds and classes of bioactive compounds in pequi pulp and oil, hydrophilic, and lipophilic extracts were performed using spectroscopy and liquid chromatographic methods, while the beneficial effects, such as antioxidant capacity in vitro, were determined using methods based on single electron transfer reaction or hydrogen atom transfer, while for antioxidant and antiproliferative activities ex vivo, 20 healthy volunteers were recruited. Human peripheral blood mononuclear cells (MN) were collected, and cellular viability assay by MTT (3-(4,5-dimethylthiazol-2-yl)-2,5 diphenyltetrazolium bromide), superoxide anion evaluation, and CuZn-superoxide dismutase determination (CuZn-SOD) in MN cells, MCF-7 cells, and coculture of MN cells and MCF-7 cells in the presence and absence of pequi pulp or oil hydrophilic and lipophilic extracts were performed. RESULTS: In the hydrophilic extract, the pequi pulp presented the highest phenolic content, while in the oil lipophilic extract, it had the highest content of carotenoids. The main phytosterol in pequi oil was ß-sitosterol (10.22 mg/g), and the main tocopherol was γ-tocopherol (26.24 µg/g sample). The extracts that had highest content of bioactive compounds stimulated blood mononuclear cells and also improved SOD activity. By evaluating the extracts against MCF-7 cells and coculture, they showed cytotoxic activity. CONCLUSION: The results support the anticarcinogenic activity of pequi extracts, in which the pequi pulp hydrophilic extracts presented better immunomodulatory potential.

Gelatine/PVA copolymer film incorporated with quercetin as a prototype to active antioxidant packaging.

Films that incorporate antioxidant agents are widely used and improve the stability of food products that are prone to oxidation. This work evaluated the potential antioxidant activity of PVA/gelatine films incorporated with quercetin. The films were prepared by the casting method and characterised by TG-DSC, FTIR spectroscopy, SEM, optical microscopy and swelling index. Antioxidant properties were evaluated with DPPH, ABTS and FRAP assays. According to the thermal characterisation results, the film was stable up to 68 °C and entirely degraded at 632 °C. The FTIR spectroscopic analysis indicated that there was a physical interaction between the quercetin and the polymeric film, and microscopy indicated a homogeneous and uniform film. The film showed DPPH (315.4 ± 8.2) and ABTS radical potential activity (199.4 ± 9.7), as well as potential iron reduction activity-FRAP (740.6 ± 8.9) mainly when analysed in ethanol: water (95:5 v/v) system, all results expressed as milligram of Trolox per gram of film. Hence, PVA/gelatine films incorporated with quercetin have properties that allow a potential application in active packaging systems to delay oxidative processes in food.

Syneresis and chemical characteristics of fermented rice extract with probiotic bacteria and waxy maize starch

Abstract The objective of this work was to elaborate fermented extracts using rice bran and broken rice grains (proportion 8:92) with probiotic bacteria and different concentrations of waxy maize starch (WMS) in order to obtain products with low level of syneresis and desirable physical-chemical characteristics, and to evaluate the content of phenolic compounds, antioxidant capacity and chemical composition of the extract selected and flavored with strawberry aroma and strawberry syrup. A randomized design was used with five treatments (0, 4, 8, 12 and 16 g 100 g-1 of WMS) and four replications. The fermented rice extract had increased soluble solids (from 12.97 to 14.23 °Brix) and total acidity (from 0.29 to 0.30 g 100 g-1), whereas total soluble sugars (from 9.24 to 8.73 g 100 g-1) and syneresis (from 10.16 to 0.99 g 100 g-1) decreased with gradual increments of waxy maize starch. The fermented rice extract containing 12 g 100 g-1 WMS reduced the syneresis by 89% compared to the control without waxy maize starch. The fermented rice extract with 12 g 100 g-1 of waxy maize starch flavored with strawberry aroma and strawberry syrup shows high nutritional value, antioxidant capacity, content of total phenolic compounds, and marketing potential, particularly for consumers with special needs, such as those allergic to lactose or soybean proteins, as an alternative food ready for consumption.

Effect of drying methods on the phenolic content and antioxidant capacity of Brazilian winemaking byproducts and their stability over storage.

This work aimed to study the antioxidant capacity by different methods, the total content of polyphenols and the stability over time of dried byproducts from Brazilian hybrids and Vitis vinifera varieties. Oven-dried at 50 °C and spray-dried samples were monitored for 90 days of storage. Under testing conditions, BRS Violeta grapes showed the greatest stability and initial high levels of total phenolics and anthocyanins remained almost unchanged until the end of storage period. The same behavior was observed in BRS Violeta freeze-dried skins, seeds and lees (8557, 9520 and 4261 mg GAE/100 g DM, respectively, and 829 and 257 mg mv-3-glc/100 g DM in skin and lees, respectively). In all methodologies tested, BRS Violeta also showed higher values for antioxidant capacity. These results suggest that dried winemaking byproducts can be used as rich sources of polyphenol compounds for industrial extractions with high stability and antioxidant capacity.

Antioxidant activity of hydrophilic and lipophilic extracts of Brazilian blueberries.

Hydrophilic and lipophilic extracts of ten cultivars of Highbush and Rabbiteye Brazilian blueberries (Vaccinium corymbosum L. and Vacciniumashei Reade, respectively) that are used for commercial production were analysed for antioxidant activity by the FRAP, ORAC, ABTS and ß-carotene-linoleate methods. Results were correlated to the amounts of carotenoids, total phenolics and anthocyanins. Brazilian blueberries had relatively high concentration of total phenolics (1,622-3,457 mg gallic acid equivalents per 100 g DW) and total anthocyanins (140-318 mg cyanidin-3-glucoside equivalents per 100 g DW), as well as being a good source of carotenoids. There was a higher positive correlation between the amounts of these compounds and the antioxidant activity of hydrophilic compared to lipophilic extracts. There were also significant differences in the level of bioactive compounds and antioxidant activities between different cultivars, production location and year of cultivation.

Phenolic composition of grape and winemaking by-products of Brazilian hybrid cultivars BRS Violeta and BRS Lorena.

The phenolic composition of grapes and winemaking by-products (skins from grape marc, and lees) from Brazilian hybrid cultivars BRS Violeta (red) and BRS Lorena (white) was studied. Two vintages, five classes of phenolic compounds, and recovery yields using three dehydration techniques were considered: oven-drying at 50°C (D50); spray-drying (SD); and freeze-drying (FD). Recovery yields were higher using FD, although less expensive SD was a good alternative for Violeta lees. D50 caused great recovery reduction in Violeta but yielded similar results for Lorena. Violeta winemaking by-products were excellent sources of anthocyanins (mainly non-acylated and p-coumaroylated diglucosides), flavonols (mainly myricetin-based) and hydroxycinnamic derivatives (mainly caffeic-based). Lorena winemaking by-products contained lesser amounts of phenolic compounds, around a tenth of the values found in Violeta grapes for flavonols (mainly quercetin-based), hydroxycinnamic derivatives (mainly caffeic-based) and condensed tannins. Lorena cultivar contained small amounts of trans-resveratrol and its 3-glucoside, which were missing in Violeta cultivar.