Search results for "Polyphenol"
showing 10 items of 514 documents
Evaluation of the Ability of Polyphenol Extracts of Cocoa and Red Grape to Promote the Antioxidant Response in Yeast Using a Rapid Multiwell Assay
2017
Saccharomyces cerevisiae has been used as a model organism to study the capacity of cocoa and red grape extracts to trigger an antioxidant response. A methodology adapted to microtiter plates has been developed to monitor yeast growth after culture preincubation with food ingredients and exposure to oxidative stress by hydrogen peroxide and menadione. This methodology proved effective in measuring the ability of cocoa and red grape extracts to promote an antioxidant response in yeast, and also the prospect of conducting dose-response studies. Additionally, the method has proven useful to perform studies with mutant strains lacking genes that may be related to the mechanism of action underly…
Laccases of Botrytis cinerea
2017
Phenolic compounds significantly affect the color, odor and taste of wine. Due to their presumptive beneficial impact on human health, polyphenols in red wine have gained increasing public and scientific interest. Wine phenols are extremely sensitive to oxygen and are easily converted to brownish oxidation products accompanied by loss of nutritive values of the wine. Enzymatic oxidation takes place under the influence of polyphenoloxidases including tyrosinases and laccases. The latter are produced by the phytopathogenic fungus Botrytis cinerea and enter the must with contaminated berries. Although uncontrolled action of Botrytis-laccase has a dramatic impact on wine quality, the oxidative …
High‐power ultrasound altered the polyphenolic content and antioxidant capacity in cloudy apple juice during storage
2019
The aim was to investigate the influence of high‐power ultrasound treatment (HPU) on polyphenolic stability and antioxidant capacity in cloudy apple juice during 7 days of storage at 4°C. HPU (100 W, 30 kHz frequency) was operated at: (i) amplitude 40 versus 80%, (ii) the probe diameter 7 versus 10 mm, and (iii) treatment time of 3, 6, and 9 min. Total phenols (TP), total flavan‐3‐ols (TFL), and in vitro antioxidant capacity (DPPH and FRAP) were determined spectrophotometrically. Findings revealed that HPU significantly decreased TP, TFL, and antioxidant capacity in the samples. However, results indicated that examined sonication parameters, represented as the probe diameter and treatment t…
A one step enhanced extraction and encapsulation system of cornelian cherry (Cornus mas L.) polyphenols and iridoids with β-cyclodextrin
2021
Abstract The objective of this study was simultaneous extraction and encapsulation of cornelian cherry active principles. As an encapsulating agent, β-cyclodextrin (β-CD) was used to enhance the ultrasound-assisted extraction of cornelian cherry polyphenols and iridoids. Lyophilized cornelian cherry fruit was extracted by four different solvents: pure water, 50% aqueous ethanol (conventional system), 1.5% β-CD water solution and 1.5% β-CD aqueous ethanol solution. The highest enhancement of the extraction efficiency was observed for flavonoids and anthocyanins, especially for cyaniding 3-galactoside and pelargonidin 3-galactoside. Water-ethanolic extract was used to form inclusion complexes…
Evaluation of fruit quality and antioxidant activity of kiwifruit during ripening and after storage
2016
BACKGROUND: In the Northern hemisphere kiwifruit harvest time is conditioned by low temperatures occurring during the harvesting season while in Southern Italy minimum temperatures in autumn are high enough to support fruit growth and ripening. OBJECTIVE: To evaluate the influence of delayed harvest time on kiwifruit quality attributes. METHODS: The experiment was carried out in a commercial kiwifruit, 'Hayward', orchard located in Southern Italy. In this area, the conventional harvest time occurs 160 days after full bloom (DAFB), during the first decade of November. Fruits were collected from 130 DAFB to 192 DAFB. Fresh fruit and dry weight, flesh color, firmness, total soluble solids cont…
Sicilian Myrtle Diversity: Evaluation of Leaf Total Phenols Content and Antioxidant Properties
2017
Myrtle (Myrtus communis L.) is an aromatic plant spontaneously growing and increasingly cultivated in Mediterranean area. Recently, interest on myrtle plant is growing due to the pharmacological and antioxidant properties since myrtle leaves are important sources of phenolic and antioxidant compounds with health-promoting effects. Plant genotype is the primary factor affecting antioxidant activity and phenol content. For this reason, a core collection of local selected myrtle accessions from Sicily was evaluated with the aim to identify genotypes with high antioxidant value. Thirty-six myrtle individuals belonging to seven populations were studied for leaf total phenols, tannins and antioxi…
Development of a low-alcoholic fermented beverage employing cashew apple juice and non-conventional yeasts
2019
Cashew apples are by-products in the production of cashew nuts, which are mostly left to rot in the fields. Cashew apple juice (CAJ), a highly nutritious beverage, can be produced from them. It is rich in sugars and ascorbic acid, but its high polyphenol content makes it bitter and astringent, and therefore difficult to commercialize. The kingdom of fungi contains more than 2000 yeast species, of which only a few species have been studied in relation to their potential to produce aroma compounds. The aim of this research was to develop a new low-alcoholic fermented beverage to valorize cashew apples. For this purpose, a screening was carried out employing non-conventional yeast species and …
Berry Size and Qualitative Characteristics of Vitis vinifera L. cv. Syrah
2016
The effect of variation in berry size on berry composition was studied in irrigated Syrah/R99 grapevines, located in a temperate area of South Africa. Berries from 45 clusters, sampled from both sides of the canopy (east and west), were weighed to create four categories: 1. less or equal to 1.5 g; 2. between 1.51 g and 2.00 g; 3. between 2.01 g and 2.50 g; 4. more than 2.50 g. Berry physical characteristics were determined and total anthocyanins and seed flavonoids were analysed by spectrophotometry and anthocyanin profiles by HPLC. The ratio of skin weight:berry weight did not change with increasing berry size, but the ratio of seed weight:berry weight increased. For total anthocyanins, va…
Improved Extraction Efficiency of Antioxidant Bioactive Compounds from Tetraselmis chuii and Phaedoactylum tricornutum Using Pulsed Electric Fields
2020
Pulsed electric fields (PEF) is a promising technology that allows the selective extraction of high-added value compounds by electroporation. Thus, PEF provides numerous opportunities for the energy efficient isolation of valuable microalgal bioactive substances (i.e., pigments and polyphenols). The efficiency of PEF-assisted extraction combined with aqueous or dimethyl sulfoxide (DMSO) solvents in recovering pigments and polyphenols from microalgae Tetraselmis chuii (T. chuii) and Phaeodactylum tricornutum (P. tricornutum) was evaluated. Two PEF treatments were applied: (1 kV/cm/400 pulses, 3 kV/cm/45 pulses), with a specific energy input of 100 kJ/kg. The total antioxidant capacity (TAC) …
Stirring-assisted dead-end ultrafiltration for protein and polyphenol recovery from purple sweet potato juices: Filtration behavior investigation and…
2016
The potential of stirring assisted dead-end ultrafiltration (UF) to recover polyphenols from purple sweet potato (PSP) juices was evaluated. For this purpose, the effects of rotation speed (200–600 rpm), transmembrane pressure (TMP) (0.2–0.4 MPa), and membrane molecular weight cut-off (30–100 kDa) were investigated with a lab-scale filtration module. The results showed that the highest protein removal (86%) and polyphenol selectivity (12.2) were both obtained under higher rotation speed (600 rpm). Moreover, filtration flux was more important at 600 rpm due to the anti-fouling effect of shear rate generated by the rotation. The results also revealed that under TMP of 0.4 MPa, the cake resist…