Dulce Antunes

Anthocyanin Concentration of “Assaria” Pomegranate Fruits During Different Cold Storage Conditions

The concentration of anthocyanins in fruits of “Assaria” pomegranate, a sweet Portuguese cultivar typically grown in Algarve (south Portugal), was monitored during storage under different conditions. The fruits were exposed to cold storage (5°C) after the following treatments: spraying with wax; spraying with 1.5% CaCl2; spraying with wax and 1.5% CaCl2; covering boxes with 25 μc thickness low-density polyethylene film. Untreated fruits were used as a control. The anthocyanin levels were quantified by either comparison with an external standard of cyanidin 3-rutinoside (based on the peak area) or individual calculation from the peak areas based on standard curves of each anthocyanin type. The storage time as well as the fruit treatment prior to storage influenced total anthocyanin content. The highest levels were observed at the end of the first month of storage, except for the fruits treated with CaCl2, where the maximal values were achieved at the end of the second month. The anthocyanin quantification method influenced the final result. When total anthocyanin was calculated as a sum of individual pigments quantified based on standard curves of each anthocyanin type, lower values were obtained.

The Effect of Two Methods of Pomegranate (Punica granatum L) Juice Extraction on Quality During Storage at 4∘C

The effect of two extraction methods of pomegranate juice on its quality and stability was evaluated. The first method consisted of separation of the seeds from fruits and centrifugation. The second method consisted of squeezing fruit halves with an electric lemon squeezer. During a period of 72 hours of cold storage at 4°C, the juices were evaluated for the presence of sugars, organic acids, and anthocyanins. Delphinidin 3-glucoside was identified to be the major anthocyanin present at the level of 45–69 mg/L. Among the organic acids, oxalic and tartaric acids dominated. The major sugars detected in pomegranate juice were glucose and sucrose. No significant differences in the content of sugars, organic acids, or anthocyanins in juices obtained through application of the two different extraction methods were detected, with the exception of the drastic decrease of cyanidin 3,5-diglucoside level in juice obtained by seed centrifugation. The pH did not show differences between treatments. Titrable acidity and the level of sugars expressed as °Brix decreased after 32 and 15 hours after extraction, respectively, when juice was obtained by centrifuging the seeds.

Physicochemical Characterization and Antioxidant Activity of Commercial Portuguese Honeys

The present study evaluated the physicochemical characteristics and antioxidant activity of 13 commercial honeys from diverse floral origin, produced in Portugal. The values of electrical conductivity of cardoon and pennyroyal honeys were superior to the maximum limits defined by European legislation. Citrus, strawberry tree, and 1 sample of lavender honeys had values of diastase activity below those determined by European legislation. Strawberry tree, pennyroyal, and cardoon honeys had the highest amounts of potassium that coincided with the highest electrical conductivity. Strawberry tree honey was the most effective as antioxidant along with cardoon and heather honeys. This ability was strongly correlated with the amounts of phenols and flavonoids and not with the levels of vitamin C or proline.

Physicochemical characterization and antioxidant activity of 17 commercial Moroccan honeys

Abstract In this study, 17 commercial honey samples from Morocco were analyzed. Four samples did not meet the international physicochemical standards due to high hydroxymethylfurfural content and low diastase activity. Phenol content varied from 163.82 mg gallic acid equivalent (GAE)/kg in citrus honey to 923.70 mg (GAE)/kg in thyme honey from Rachidia; flavonoid content ranged from 4.26 mg quercetin equivalent (QE)/kg in citrus honey to 139.62 mg QE/kg in black cumin honey. Black cumin honey had the highest peroxyl scavenging activity; oregano (from Zaraphyt) and thyme honeys (from Rachidia) had the highest ABTS (2,2′-azino-bis[3-ethylbenzothiazoline-6-sulphonic acid]) scavenging activity; and thyme honey (Saouira) had the highest NO scavenging capacity. The antioxidant activity of Moroccan honeys was correlated with the phenol, flavonoid, and melanoidin contents. Dark honeys had higher antioxidant activity than light honeys. Samples with high sodium levels had lower free radical scavenging activity. On the other hand, calcium and magnesium increased the ABTS and peroxyl scavenging capacity, respectively, of honey samples. According to cluster and discriminant analyses, the honey samples were grouped in three clusters with respect to the phenol, flavonoid, melanoidin, proline, mineral and sugar contents, and free radical scavenging capacity.

Antioxidant, anti-inflammatory and acetylcholinesterase inhibitory activities of propolis from different regions of Morocco

Propolis is a bee product used since ancient times in folk medicine. Antioxidant activity is one of the properties attributed to this natural product, which varies depending on the botanical and geographic origin. The antioxidant capacities of propolis from different regions of Morocco were determined. Samples from the Khamissat and Immouzzer regions showed the highest antioxidant activities (ABTS assay), reducing power, and peroxyl and hydroxyl radical scavenging capacities. The best capacities to inhibit 5-lipoxygenase were found in propolis samples from Rabat. A strong correlation was found between the amounts of phenols, flavonoids, and antioxidant and anti-inflammatory activities. These results support the hypothesis that phenols contribute greatly to the pharma-cological properties of propolis and suggest that propolis could be important in prevention of diseases in which free radicals are implicated.

Ability of scavenging free radicals and preventing lipid peroxidation of some phenols and ascorbic acid

Article history: Received on: 06/05/2015 Revised on: 05/06/2015 Accepted on: 17/06/2015 Available online: 28/08/2015 The capacity for scavenging free radicals and preventing lipid peroxidation of gallic, caffeic, and p-coumaric acids, thymol, eugenol and ascorbic acid were evaluated. The capacity for scavenging DPPH  free radicals were performed in ethanol 96% and ethanol 70%. In the same assay, the activity estimation was followed at 10, 20 and 30 minutes. In this assay, eugenol presented the best activity (IC50 ranging from 2.10 mg/mL to 9.74 mg/mL. In the opposite site, p-coumaric had the lowest activity, in which the IC50 values were not possible to determine. Generally, 10 minutes of reaction provided lower scavenging activities than 30 minutes. The sole exception was ascorbic acid in which the activities were independent on the time of reaction. Ascorbic acid, eugenol and thymol possessed higher ability for scavenging DPPH free radicals in ethanol 70% than in ethanol 96%. Gallic and pcoumaric acids as well as thymol revealed to be the best scavengers of ABTS + free radicals in contrast to ascorbic acid. The capacity for preventing lipid peroxidation was dependent on the concentration of samples. The assay showed that higher concentrations of gallic acid, thymol and p-coumaric acid added to sunflower oil (from 0.3 to 0.6%) induced higher lipid peroxidation with higher peroxide values. In contrast, increasing the percentages of caffeic acid and eugenol induced lower peroxidation of the sunflower oil. The percentage of samples added to this fat did not influence the index of p-anisidine. In this test, gallic acid had the best capacity for preventing the formation of 2,4-dienals and 2-alkenals decadienals able to react with p-anisidine.

Targeted gene disruption coupled with metabolic screen approach to uncover the LEAFY COTYLEDON1-LIKE4 (L1L4) function in tomato fruit metabolism

Key messageFunctional analysis of tomato L1L4 master transcription factor resulted in important metabolic changes affecting tomato fruit quality.AbstractTomato fruits from mutant lines bearing targeted disruption of the heterotrimeric nuclear transcription factor Y (NF-Y) transcription factor (TF) gene LEAFY-COTYLEDON1-LIKE4 (L1L4, NF-YB6), a master regulator of biosynthesis for seed storage proteins and fatty acids, were evaluated for metabolites content and morphology. Metabolic screens using LC–MS/MS-based analysis and physico-chemical methods in different L1L4 mutants of the fourth generation allowed a comparative assessment of the effects of the TF disruption. Mutagenesis resulted in fruits phenotypically similar to wild-type with subtle shape differences in the distal end protrusion and symmetry. Conversely, mutant fruits from independent lines had significant variation in moisture content, titratable acidity and overall metabolite profiles including oxalic and citric acid, fructose, β-carotene, total polyphenols and antioxidants. Lines 6, 7 and 9 were the richest in β-carotene and antioxidant activity, line 4 in ascorbic acid and lines 4 and 8 in succinic acid. The reduced content of the anti-nutrient oxalic acid in several mutant fruits suggests that L1L4 gene may regulate the accumulation of this compound during fruit development. Detailed LC–MS/MS analysis of mutant seeds showed substantial differences in bioactive compounds compared to wild-type seeds. Taken together, the results suggest that the L1L4 TF is a significant regulator of metabolites both in tomato fruit and seeds providing a molecular target for crop improvement. Elucidation of the candidate genes encoding key enzymes in the affected metabolic pathways aimed to facilitate the L1L4 gene network exploration and eventually lead to systems biology approaches in tomato fruit quality.