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The extraction of secondary metabolites by water, MeOH:water (8:2) containing NaF, methanol, ethanol and acetone (all of them diluted (7:3) in water)from the different parts (leaves, flowers, stems and roots) of Passiflora caerulea L., Physalis peruviana L. and Solanum muricatum Aiton via decoction and maceration methods was studied. The highest extraction yields were recorded by methanol for decoction and acetone for maceration. The total polyphenol content (TPC) obtained by decoction had the highest TPC contents, and MeOH containing NaF was the best solvent for the extraction of TPC. Maceration was suitable for flavonoid extractions, with ethanol and acetone being the best solvents. In general, the highest levels of TPC and flavonoids were obtained from Passiflora leaves regardless of the solvent or extraction method applied. Furthermore, the roots of Physalis and Solanum showed important levels of these compounds in consonance with the total antioxidant activity (TAA) evaluated in the different organs of the plant in the three species. In this study, the solvents and extraction methods applied were tools that determined significantly the level of extraction of bioactive compounds, showing a different impact on plant organs for each medicinal species studied.

Polyphenolic compounds (PCs) have received exceptional attention at the end of the past millennium and as much at the beginning of the new one. Undoubtedly, these compounds in foodstuffs provide added value for their well-known health benefits, for their technological role and also marketing. Many efforts have been made to provide simple, effective and user friendly analytical methods for the determination and antioxidant capacity (AOC) evaluation of food polyphenols. In a parallel track, over the last twenty years, nanomaterials (NMs) have made their entry in the analytical chemistry domain; NMs have, in fact, opened new paths for the development of analytical methods with the common aim to improve analytical performance and sustainability, becoming new tools in quality assurance of food and beverages. The aim of this review is to provide information on the most recent developments of new NMs-based tools and strategies for total polyphenols (TP) determination and AOC evaluation in food. In this review optical, electrochemical and bioelectrochemical approaches have been reviewed. The use of nanoparticles, quantum dots, carbon nanomaterials and hybrid materials for the detection of polyphenols is the main subject of the works reported. However, particular attention has been paid to the success of the application in real samples, in addition to the NMs. In particular, the discussion has been focused on methods/devices presenting, in the opinion of the authors, clear advancement in the fields, in terms of simplicity, rapidity and usability. This review aims to demonstrate how the NM-based approaches represent valid alternatives to classical methods for polyphenols analysis, and are mature to be integrated for the rapid quality assessment of food quality in lab or directly in the field.

Limonium brasiliense is a common plant on the southern coast of Brazil. The roots are traditionally used for treatment of premenstrual syndrome, menstrual disturbances and genito-urinary infections. Pharmaceutical preparations obtained from its roots and used for these purposes were marketed in Brazil in the 1980s and 1990s. Currently, the Brazilian Drug Agency (National Health Surveillance Agency, ANVISA) has canceled the registration of these products, and their use was discontinued because of a lack of studies to characterize the plant raw material and ensure the effectiveness and safety of its use. The aim of the present study was to develop and validate an analytical method to determine the content of total polyphenols (TP) in an extract from L. brasiliense roots, by the UV/Vis spectrophotometric method. L. brasiliense roots were extracted in acetone:water (7:3, v/v-10% w/v). The crude extract was used to develop a method for TP assay. The method was validated according to national and international guidelines. The optimum conditions for analysis time, wavelength, and standard substance were 30 min, 760 nm, and pyrogallol, respectively. Under these conditions, validation by UV/Vis spectrophotometry proved the method to be linear, specific, precise, accurate, reproducible, robust, and easy to perform. This methodology complies with the requirements for analytical application and to ensure the reliability of the results.

The objective of this study is to valorize Papaver rhoeas L. from the Taounate region of Morocco by determining the total polyphenol content (TPC), the total flavonoid content (TFC) and the antioxidant and antimicrobial activities of four organs. The quantification of TPC and TFC in root, stem, leaf and flower extracts (RE, SE, LE and FE, respectively) was estimated by the Folin–Ciocalteu reaction and the aluminum trichloride method, respectively. Two tests were used to assess antioxidant power: the DPPH test and TAC assay. The antimicrobial activity was studied against five pathogenic bacteria and yeast, using two methods: disk diffusion and microdilution. The TPC in LE and LF was twice as high as that in RE and SE (24.24 and 22.10 mg GAE/g, respectively). The TFC values in the four extracts were very close and varied between 4.50 mg QE/g in the FE and 4.38 mg QE/g in the RE. The LE and FE showed low DPPH values with IC50 = 0.50 and 0.52 mg/mL, respectively. The TAC measurement revealed the presence of a significant amount of antioxidants in the studied extracts, mainly in LE and FE (6.60 and 5.53 mg AAE/g, respectively). The antimicrobial activity results revealed significant activity on almost all of the tested strains. The MIC of FE and SE against E. coli 57 was 1.56 and 0.78 mg/mL, respectively, while against the S. aureus it was 50 and 25 mg/mL, respectively. The low MLC value (1.56 mg/mL) was recorded against E. coli 57 by RE and SE.

This study was performed to determine the possibility of using mango fruit (Mangifera indica) in brewing technology. The aim of using the SPME-HS-GC-MS technique was to assess what changes occurred in the volatile composition of mango beers brewed in this study. Mango fruit was added to the beer in five different forms to ascertain what kind of preparation should be used to improve beer aroma. Analysis of the volatile components in mango beer showed that beer without mango addition was characterized by the lowest content of volatile compounds (1787.84 µg/100 mL). The addition of mango fruit increased the concentration of compounds, such as α-pinene, β-myrcene, terpinolene, α-terpineol, cis-β-ocimene, caryophyllene, and humulene, in beer. Beer prepared with mango pulp addition was characterized by the highest concentration of volatile components from mango beers (2112.15 µg/100 mL). Furthermore, beers with mango addition were characterized by a higher polyphenol content (up to 44% higher than control beer) and antioxidant activity than control beer and were evaluated by a trained panel as having a better taste and aroma than beer without fruit addition.

The widely used methodology to quantify polyphenols—the Folin-Ciocalteu (FC) method—cannot be applied indiscriminately since different matrices may impair the assay’s accuracy. Thus, this study aimed to adapt the FC method for the açaí seed extract, a tannin-rich extract with potential applications for various therapies. Firstly, a pre-method standardization was established to determine parameters such as reading wavelength (765 nm), reaction time (30 min), and the reference substance (pyrogallol). In the validation step, the adapted method responded linearly to the analyte (R2 = 0.9910), ensuring its selectivity (linearity and selectivity curves statistically parallel) and accuracy (99.18–101.43%). Furthermore, the method proved to be precise (RSD ≤ 2.63%) at the two levels assessed (repeatability and intermediate precision) and robust (RSD ≤ 4.45%) concerning variation on the Na2CO3 concentration and the reaction time. The limits of detection and quantification were also calculated (9.9 µg/mL and 33.1 µg/mL, respectively). An additional step for tannins quantification based on its reported selective precipitation by complexing agents was also evaluated; however, unspecific precipitation was observed, reducing the results’ accuracy. Our work successfully adapted and validated a method for total phenolics quantification of açaí seed extract, resulting in 38 g of pyrogallol equivalent/100 g of extract. Graphic abstract

This study aimed to investigate the accelerated ripening of sukkari dates and examine the resulting changes in color, pulp, carbohydrates, vitamins, and antioxidant capacity using a comprehensive set of nine individual treatments. Fresh dates at the Khalal stage were subjected to immersion in normal water for 5 h or hot water for 5 min, with or without the inclusion of NaCl (2%), potassium metabisulfite (PM, 0.5%), and acetic acid (AA, 1.5%), either individually or in combination. The treated dates were then allowed to ripen for 72 h in an aerated incubator at 40 °C. Evaluation of color shade, fruit weight, pulp texture, total soluble carbohydrates (TSC), total soluble sugars (TSS), beta-carotene, total polyphenols (TPC), total flavonoids (TFC), DPPH radical scavenging activity, FRAP value, and overall appearance assessed the efficacy of each treatment. Among the treatments, T 6 (normal water with 1.5% AA + 0.5% PM) and T 8 (hot water with 1.5% AA + 0.05% PM) exhibited superior acceptance levels, characterized by softness, reduced pungency, a rich brown color, and exceptional visual appeal, with more than 77% and 88% pulp and ripened fruit, respectively. Furthermore, T 6 demonstrated higher TSC (96.70 mg g −1  FW), TSS (322.22 mg g −1  FW), DPPH radical scavenging activity (92.84%), and FRAP value (0.40), while exhibiting lower levels of beta-carotene (4.91 mg 100 g −1  FW), TPC (0.14 mg g −1  FW), and TFC (0.31 mg g −1  FW). Similarly, T 8 performed exceptionally well across all parameters except for beta-carotene.

The pseudoacacia species (Robinia pseudoacacia L.) are flowering plants that produce nectar and can be the sources of unifloral honey. Robinia is native to North America and is invasive in several European countries. The aim of this work was to determine and compare the physicochemical parameters, proline content, and antioxidant capacity of pseudoacacia honey collected from different locations in two central European countries (Hungary and Slovakia). The botanical origin of each honey sample was verified by melissopalynological analysis. The color intensity was determined using the Pfund scale. The antioxidant activity was determined with different spectrophotometric methods (DPPH, ABTS, and FRAP). The content of the total polyphenols, flavonoids, phenolic acids, and proline was quantified using spectrophotometric methods. The electrical conductivity, refractive index, and optical rotation were analyzed according to European Pharmacopoeia, 12th edition. Our study shows that the antioxidant capacity, and proline and phenolic content of unifloral pseudoacacia honeys can vary according to the geographical origin, polyphenol content, and the pollen profile in honey samples.

Based on the regulation (EU) No 2015/1107 in 8 July 2015, Willow (Salix alba) bark extract is a recent approved basic substance in Europe as a safe and effective environmentally friendly fungicide to be used in plant protection. Because of having indole butyric acid content, it is also used as a growth hormone to promote rooting in cutting propagation of wooden part in horticultural plants. This research aimed to evaluate the effect of willow extract and Ferbanat L (Bistep) on lettuce leaves. Bistep is an organic solution of nano fertilizer which is produced in Hungary and allowed as „Bistep plant conditioner”. Furthermore, the experiment evaluated their interaction on some bioactive compounds in different lettuce varieties, too. Three different lettuce varieties (King of May, Kobak and Great Lakes) were evaluated for total polyphenols, vitamin C and nitrate content in fresh leaves. The results indicate that the contents were significantly affected by the used biostimulants rather than varieties. Significantly difference of the total polyphenols was recorded in the plants treated with Willow + Bistep (80.64 mg GAE / 100g) in comparison to the control (55.85 mg GAE / 100g) in the mean of varieties. Similar result was recorded for the vitamin C. However, plants treated with Willow extract resulted in the highest level of nitrate content (692.00 mg/100g), while the lowest amount was measured in the control (488.00 mg/100g). According to our results, Willow bark extract can be a beneficial source of natural growth regulator or fungicide; however, when it is used alone for vegetables, the nutrient content (mainly nitrate level) must be checked before consuming and delivering to the market.

Prickly pear fruits are seasonal and have shades ranging from pale green to deep purple. Their pigments are associated with bioactive compounds, being sensitive to thermal transformation processes for their conservation. The objective of this research was to evaluate the bioactive compounds and the sensory analysis of freeze-dried prickly pear fruits from an inter-Andean valley in Peru. The prickly pear fruits of the morada, anaranjada, and blanca ecotypes came from an inter-Andean valley in Peru at 2972 m altitude. The sliced fruits were freeze-dried at −40 °C and 0.25 mTorr, and the total polyphenol content (TPC), vitamin C, and antioxidant activity (AA) were determined, as well as the color L* a* b*, color index (CI*), FTIR spectra, and mineral content. In the same way, sensory analysis of preferences with nine scales was applied. It was observed that in the freeze-dried fruits, TPC, AA, and vitamin C increased significantly (p-value < 0.05), and their corresponding functional groups increased in intensity in their corresponding FTIR spectra; furthermore, trace elements such as Cu, Fe, Se, Zn, Si, and Mn were identified. On the other hand, freeze-drying provided deeper colors to the fruits, which most panelists said they “very much liked” during the sensory analysis, although the texture was not very well accepted, with most panelists reporting being “indifferent” towards it. The freeze-drying technique allows the bioactive and sensory attributes of prickly pear fruits from inter-Andean valleys to be preserved, making it a potential fruit for export and conservation due to its seasonality.