Date Seed: Rich Source of Antioxidant Phenolics Obtained by Hydrothermal Treatments

peer reviewedThe growing interest in natural compounds is helping to improve the management of agro-industrial by-products such as the date seed as sources of such compounds. In this work, the application of a hydrothermal treatment at 160 and 180 °C for 60 min was studied to achieve the solubilization of its phenolic components and sugars in order to obtain biologically active extracts. The percentage of phenols and total sugars in the final extracts were very similar, at 45 and 25% for the 160 and 180 °C treatments, respectively. The treatment at a higher temperature allowed greater solubilization of other components. The antioxidant activity was measured as free-radical scavenging capacity. For the DPPH• method, expressed as EC50, the results were 0.34 and 0.37 mg/L, the TEAC values for the ABTS• method were 6.61 and 3.28 mg/g dried extract, and the values obtained by the ORAC method were 12.82 and 9.91 mmol Trolox/g dried extract, for 160 and 180 °C, respectively. All these values are higher than those of other plant extracts and extracts obtained using the whole date. Therefore, the date seed is a very important source of phenols, and through thermal and chromatographic processes, it is possible to obtain extracts with high antioxidant activity.GreenPalm of the PRIMA European Action, Project 25/Section II-2019, PCI2020-112088 MINEC

The Effect of the Extra Virgin Olive Oil Minor Phenolic Compound 3′,4′-Dihydroxyphenylglycol in Experimental Diabetic Kidney Disease

The aim of this study was to analyze the possible nephroprotective effect of 3’,4’-dihydroxyphenylglycol (DHPG), a polyphenolic compound of extra virgin olive oil (EVOO), on renal lesions in an experimental model of type 1 diabetes. Rats were distributed as follows: healthy normoglycemic rats (NDR), diabetic rats treated with saline (DR), and DR treated with 0.5 mg/kg/day or 1 mg/kg/day of DHPG. DR showed a significantly higher serum and renal oxidative and nitrosative stress profile than NDR, as well as reduced prostacyclin production and renal damage (defined as urinary protein excretion, reduced creatinine clearance, increased glomerular volume, and increased glomerulosclerosis index). DHPG reduced the oxidative and nitrosative stress and increased prostacyclin production (a 59.2% reduction in DR and 34.7–7.8% reduction in DHPG-treated rats), as well as 38–56% reduction in urinary protein excretion and 22–46% reduction in glomerular morphological parameters (after the treatment with 0.5 or 1 mg/kg/day, respectively). Conclusions: DHPG administration to type 1-like diabetic rats exerts a nephroprotective effect probably due to the sum of its antioxidant (Pearson’s coefficient 0.68–0.74), antinitrosative (Pearson’s coefficient 0.83), and prostacyclin production regulator (Pearson’s coefficient 0.75) effects.This study was supported, in part, by the Consejería de Salud. Junta de Andalucía (Spain), Proyectos de Investigación en Salud [Regional Ministry of Health. Junta de Andalucía (Spain), Health Research Projects] (PI-0129-2017). Partial funding for open access charge: Universidad de Málag

Neuroprotective Effect of 3′,4′-Dihydroxyphenylglycol in Type-1-like Diabetic Rats—Influence of the Hydroxytyrosol/3′,4′-dihydroxyphenylglycol Ratio

The aim of this study was to assess the possible neuroprotective effect of 3′,4′-dihydroxyphenylglycol (DHPG), a polyphenol from extra virgin olive oil (EVOO), in an experimental model of diabetes and whether this effect is modified by the presence of another EVOO polyphenol, hydroxytyrosol (HT). The neuroprotective effect was assessed in a hypoxia–reoxygenation model in brain slices and by quantifying retinal nerve cells. The animals were distributed as follows: (1) normoglycemic rats (NDR), (2) diabetic rats (DR), (3) DR treated with HT (5 mg/kg/day p.o.), (4) DR treated with DHPG (0.5 mg/kg/day), or (5) with 1 mg/kg/day, (6) DR treated with HT plus DHPG 0.5 mg/kg/day, or (7) HT plus 1 mg/kg/day p.o. DHPG. Diabetic animals presented higher levels of oxidative stress variables and lower numbers of neuronal cells in retinal tissue. The administration of DHPG or HT reduced most of the oxidative stress variables and brain lactate dehydrogenase efflux (LDH) as an indirect index of cellular death and also reduced the loss of retinal cells. The association of DHPG+HT in the same proportions, as found in EVOO, improved the neuroprotective and antioxidant effects of both polyphenols.This study was supported, in part, by the Consejería de Salud. Junta de Andalucía (Spain), Proyectos de Investigación en Salud [Regional Ministry of Health. Junta de Andalucía (Spain), Health Research Projects] (PI-0129-2017). Partial funding for open access charge: Universidad de Málaga

Strawberry Puree Functionalized with Natural Hydroxytyrosol: Effects on Vitamin C and Antioxidant Activity

The natural antioxidant hydroxytyrosol (HT) was used to functionalize a strawberry puree. The effect of the antioxidant on the stability of the two bioactive forms of vitamin C (ascorbic acid-AA and dehydroascorbic acid-DHAA) in strawberry puree stored at 4 °C, compared with the effect on a model system of AA in water, was investigated. In the absence of HT, the concentration of vitamin C in strawberry puree decreased but not in the model system. Low concentrations of HT in strawberry puree (0.05 and 0.1 mg HT/g puree) stabilized vitamin C and improved its antioxidant activity. However, at high concentrations of HT (from 0.5 mg HT/g puree), although the antioxidant activity improved, degradation of vitamin C occurred. Therefore, the concentration of HT used to obtain a functionalized strawberry puree it is very important. An adequate concentration increases the antioxidant activity and protects vitamin C from degradation, developing a functional food. However, an inadequate concentration of HT affects the vitamin C content, which is essential for the human diet because it cannot be biosynthetized by the organism

Viability of near infrared spectroscopy for a rapid analysis of the bioactive compounds in intact cocoa bean husk

3 Figuras.-- 4 TablasThe potential of the cocoa bean husk (CBH) as a natural source of bioactive compounds is ever-increasing. In this work, its bioactive compounds and antioxidant activity were analyzed using near infrared spectroscopy in samples of CBH. Beans were harvested and fermented in a Mexican gene bank. Reference data on total sugars, total phenols, phenolic compounds, theobromine, and antioxidant activity were correlated with the intact husk and bean spectra. The Modified Partial Least Square regression method (MPLSR) was used to develop calibrations. Good calibration statistics were obtained for total sugars (r2 = 0.90), theobromine (r2 = 0.83) and total phenols (r2 = 0.81) in data related to the CBH spectra, with a ratio of standard deviation/standard error of cross validation (RPD) of 3.16, 2.39 and 2.28, respectively. Acceptable calibrations for the estimation of bioactive compounds in CBH were obtained for the first time from the spectra of intact grain samples. Industries interested in bioactive compounds from CBH could use this technology as an easy and fast method to predict their contents, while avoiding the inconvenient de-husking process.This research was supported by the Spanish Ministry of Economy and Competitiveness and co-funded by the European Social Fund (ESF) (project AGL2016-79088R), the Spanish Ministry of Economy and Competitiveness Ramon y Cajal Programme (RyC2012-10456), the National Institute of Forestry, Agricultural and Livestock Research (INIFAP-México),and the Mexican National Council of Science and Technology (CONACyT-Mexico).Peer reviewe

New Liquid Source of Antioxidant Phenolic Compounds in the Olive Oil Industry: Alperujo Water

14 Páginas.-- 3 Figuras.-- 4 TablasThe current management of alperujo as the main solid by-product from the two-phase olive oil extraction system has led to the appearance of a new liquid effluent that until now was treated together with the alperujo itself. The composition and antioxidant properties of its bioactive components at different depths of the pond were studied using colorimetric and HPLC with UV and MS detectors, DPPH, reducing power and rancimat. The concentration of suspended solids varied between 1.71 and 8.49 g/L, total fat was between 0.74 and 1.47 g/L, and total phenols were found between 3.74 and 4.11 g/L, which included hydroxytyrosol, 3,4-dihydroxyphenylglycol and tyrosol as the main phenols. Two types of extracts were obtained through two industrial systems with ethyl acetate and by chromotography, with an average content in total sugars of 2.1% and 3.16%, total phenols of 17.9% and 28.6% and hydroxytyrosol of 51.5 and 79.0 mg/g of extract, respectively. The activity presented by the chromatographic extract was higher in terms of free radical sequestering capacity, reducing power and the inhibition of lipid oxidation. Obtaining bioactive extracts would improve the formulation of food with natural components and at the same time would be the first step in a biorefinery to improve the management of the new effluent.This research was supported by the Spanish Ministry of Economy and Competitiveness and co-funded by a European Social Fund (ESF) (project AGL2016-79088R), the Spanish Ministry of Economy and Competitiveness Ramon y Cajal Programme: (RyC 2012-10456).Peer reviewe

Confirmation by solid-state NMR spectroscopy of a strong complex phenol-dietary fiber with retention of antioxidant activity in vitro

9 páginas.- 7 figuras.- 35 referenciasThe aim of this study was to prepare a complex between the olive phenolic compounds, hydroxytyrosol (HT), 3,4-dihydroxyphenylglycol (DHPG) and their mixture, with the soluble and insoluble dietary fiber of apple cell wall. A strong interaction between phenols and the apple cell wall occurred during the drying phase and it was confirmed by ultraviolet–visible spectrometry, Fourier transform infrared spectrometry, differential scanning calorimetry, thermogravimetry and especially by solid-state 13C NMR spectroscopy. The antiradical activity by DPPH, ABTS and ORAC assays confirmed that the simple phenolic HT/DHPG maintained in part their antioxidant activity after complexation with the apple cell wall. In addition, the HT/DHPG-soluble and insoluble fractions obtained after simulated gastrointestinal fluids retained this antioxidant activity. These complexes may be protected from absorption during gastrointestinal transit to reach the colon. In the case of the soluble dietary fiber, an enzymatic treatment, in a simulation of hydrolysis by colonic microflora, released oligomers with potential antioxidant activity from this complex. Therefore, the intake of HT/DHPG bound to the fiber of apple cell wall could provide many of the health benefits associated with dietary fiber, and be fermented by gut bacteria to contribute to a healthy antioxidant environment. © 2019 Elsevier LtdThis work was supported by the Ministerio de Ciencias, Innovación y Universidades of Spain and co-funded by European Social Fund (ESF) [AGL2016-79088-R). A. Bermúdez-Oria received funding from the Spanish FPI program (MEIC) (BES-2014-068508). The funders had no involvement in study design, collection, analysis or interpretation of data, writing of the report, or in the decision to submit the article for publication.Peer reviewe

Physical and functional properties of pectin-fish gelatin films containing the olive phenols hydroxytyrosol and 3,4-dihydroxyphenylglycol

29 Páginas; 6 Figuras; 2 TablasThis study describes the development of a composite edible film based on pectin and fish skin protein capable of protecting food from microbial attack and oxidative degradation. The film was prepared with glycerol as plasticizer and the antioxidant and antimicrobial phenolic compounds hydroxytyrosol (HT) and 3,4-dihydroxyphenylglycol (DHPG), extracted from olive fruit, as active agents. The influence of the concentration of plasticizer and active HT/DHPG on the mechanical and functional properties of the films was investigated, with values of water vapor permeability (WVP) between 0.13–0.22 g mm/h m2 kPa and oxygen permeability (OP) between 9.91–40.76 cm3 μm/m2 d kPa. The release behavior in water at different pH values was also evaluated. The antimicrobial capacity of the novel food coating was tested on strawberries, a fruit with high perishability. The bioactive edible film containing HT/DHPG preserved the strawberries against mold during storage with a significant delay in visible decay.This research was supported by the Spanish Ministry of Economy, Industry and Competitiveness and co-funded by a European Social Fund (ESF) (Ramon y Cajal Programme RyC 2012–10456; project AGL2013-48291-R and project AGL2016-79088-R) and A. Bermúdez-Oria received funding from the Spanish FPI program (MEIC) (BES-2014-068508).Peer reviewe

Strawberry dietary fiber functionalized with phenolic antioxidants from olives. Interactions between polysaccharides and phenolic compounds

The interaction of strawberry cell wall with hydroxytyrosol (HT) and 3,4-dihydroxyphenylglycol (DHPG), two potent phenolic antioxidants naturally found in olive fruit with important biological properties, was investigated. The interaction occurred with drying and seemed to be more complex, strong and irreversible than a simple association. MALDI TOF-TOF analysis suggested covalent (ester bond) and non-covalent (strong hydrogen-bonding, mostly) interactions. The oxygen radical absorbance capacity (ORAC) assay confirmed that the phenols maintained partially their antioxidant activity after binding to the soluble dietary fraction. This soluble dietary fiber was obtained following digestion simulated in vitro with gastric and intestinal fluids. Although the antioxidant activity of HT and DHPG was affected by the dietary fiber interaction, this activity was restored when polysaccharide size was reduced by enzymatic treatment, suggesting that a similar process could occur in the colon. Thus, the use of this novel antioxidant-enriched soluble dietary fiber as a functional food ingredient could potentially promote intestinal health.Funding was received from the Ministerio de Economía, Industria y Competitividad of Spain and co-funded by European Social Fund (ESF) [Project AGL2013-48291-R].Peer Reviewe

Effect of the Olive Oil Extraction Process on the Formation of Complex Pectin–Polyphenols and Their Antioxidant and Antiproliferative Activities

The aim of this research was to investigate the interaction of phenols and pectic polysaccharides during the olive oil extraction process. For this, pectin was extracted from fresh olive fruits and compared to the pectin isolated from the paste resulting from the extraction of the olive oil after milling with malaxation at 30 °C/30 min and subsequent centrifugation of the olive paste from the same lot of olive fruits in a system called ABENCOR (AB). The results indicate that these interactions were enhanced during the olive oil extraction process. In addition, the resulting AB extracts exhibited high antioxidant activity (ORAC) and strong antiproliferative activity in vitro against colon carcinoma Caco-2 cell lines compared to olive fruit extracts. The polyphenols associated mainly with the acidic pectin substance, with a higher content in AB extracts, seem to be responsible for these activities, and appear to maintain their activities in part after complexation. However, even in olive fruit extracts with smaller amounts of phenols in their compositions, pectic polysaccharides may also be involved in antioxidant and antiproliferative activities