Mediterranean Institute for Agriculture, Environment and Development

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Comparative study of the antioxidant and enzyme inhibitory activities of two types of Moroccan Euphorbia entire honey and their phenolic extracts

Publication . Boutoub, Oumaima; EL-GUENDOUZ, Soukaina; Manhita, Ana; Dias, Cristina Barrocas; Estevinho, Letícia M.; Paula, Vanessa B.; Carlier, Jorge; Costa, Maria Clara; Rodrigues, Brígida; Raposo, Sara; Aazza, Smail; El Ghadraoui, Lahsen; Miguel, Maria Graça

Honey is a natural food product very famous for its health benefits for being an important source of antioxidant and phenolic compounds. Euphorbia honeys obtained from different regions of Morocco were evaluated for their ability to inhibit acetylcholinesterase, lipoxygenase, tyrosinase and xanthine oxidase activities. Their antioxidant properties were evaluated using the: 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical-scavenging capacity, nitric oxide scavenging activity (NO) and scavenging ability of superoxide anion radical. Then, the phenolic extracts of the same entire honey samples were evaluated by liquid chromatography coupled to diode array detection and mass spectrometry (LC-DAD-MS) and tested for the biological activities previously evaluated on the entire honeys, in order to conduct a comparative study between both (honey and phenolic extracts). The chromatographic profiles for the studied Euphorbia honey extracts were different. Phenolic compounds gallic acid, 4-hydroxybenzoic acid and p-coumaric acid were detected in all samples, whereas kampferol was only present in two samples. Physicochemical parameters and total phenolic content were also determined. Entire honey that recorded the highest rate of phenols was sample M6 (E. resinifera) = 69.25 mg GAE/100 g. On the other hand, the phenolic extracts had better antioxidant and enzyme inhibitory activities than the entire honeys, regardless the monofloral honey type. In conclusion, the studied Euphorbia honeys may have a great potential as antioxidant, anti-inflammatory and anti-tyrosinase sources for pharmaceutical and cosmetic applications.

2021-08-17Journal article

Open Access

Quality and biological properties of vinegar processed from non-valorized fruits in Southern Portugal

Publication . Silva, Vanessa; Raouf Mehrpour, Gisou; Soares, Vera; Santo, David; A. Nunes, Patrícia; Quintas, Célia

The processing of vinegar from non-valorized fruits and agricultural surpluses is an attractive strategy for biomass waste management. The present study aimed to characterize vinegar of fermented fruits, namely fresh fig, plum, dried fig, grape, raspberry, and apricot. Physicochemical and microbial quality, total phenolic content (TPC), total flavonoid content (TFC), total antioxidant capacity (TAC), mineral composition, and antimicrobial capacity against bacteria and yeasts were studied. Grape and apricot vinegar had the highest values of TAC (39.31 +/- 0.25, 34.10 +/- 1.44 DPPH mu g Trolox/100 mL, respectively), while grape contained the highest TFC (35.73 +/- 3.86 mg catechin/100 mL) and raspberry and fresh fig, the highest TPC (55.40 +/- 1.1, 64.10 +/- 0.0 mg gallic acid/ 100 mL, respectively). Potassium, calcium and sodium were the most abundant minerals in the vinegars with dried fig standing out for its richness in potassium 1223.83 +/- 89.48 mg/L, calcium 17.70 +/- 1.31 mg/L, magnesium 2.39 +/- 0.24 mg/L, and zinc 4.33 +/- 0.17 mg/L. The enterobacteria Cronobacter sakazakii and Salmonella Typhimurium were the most tolerant (10.00 +/- 0.00-26.39 +/- 1.60 mm), while Pseudomonas aeruginosa was the most sensitive bacteria (26.36 +/- 3.61-40.17 +/- 2.72 mm) as well as Gram + ( Staphylococcus aureus, Listeria innocua ) (21,20 +/- 8,37-31.11 +/- 2.41 mm). The acetification processes resulted in vinegars with a good hygienic status, and levels of acetic acid ( >= 5 %) complying with the legislation.

2024Journal article

Open Access

UV-C light: a promising preservation technology for vegetable-based nonsolid food products

Publication . Tchonkouang, Rose Daphnee; Ribeiro Lima, Alexandre; Quintino, Andreia; Cristofoli, Nathana L.; Vieira, Margarida

A variety of bioactive substances present in fruit- and vegetable-processed products have health-promoting properties. The consumption of nutrient-rich plant-based products is essential to address undernutrition and micronutrient deficiencies. Preservation is paramount in manufacturing plant-based nonsolid foods such as juices, purees, and sauces. Thermal processing has been widely used to preserve fruit- and vegetable-based products by reducing enzymatic and microbial activities, thereby ensuring safety and prolonged shelf life. However, the nutritional value of products is compromised due to the deleterious effects of thermal treatments on essential nutrients and bioactive compounds. To prevent the loss of nutrients associated with thermal treatment, alternative technologies are being researched extensively. In studies conducted on nonsolid food, UV-C treatment has been proven to preserve quality and minimize nutrient degradation. This review compiles information on the use of UV-C technology in preserving the nutritional attributes of nonsolid foods derived from fruit and vegetables. The legislation, market potential, consumer acceptance, and limitations of UV-C are reviewed.

2023-08-27Journal article

Open Access

Influence of the drought on antioxidant and enzymatic activities of two Pinus species in humid and sub-humid climate

Publication . Sameh, Cherif; Hanene, Ghazghazi; Olfa, Ezzine; Salima, Bahri; Khouja, Mohamed L; Zouhaier, Nasr; Graça, Miguel M.

Pinus genus is widespread in the Mediterranean region and the most common in Tunisia. The impact of high temperatures in the mid-summer period (July 2015 and July 2016) on phenols and biological properties were examined in vitro. The study was carried out in two arboreta, in humid and sub-humid climates, dry needles of Pinus pinea and Pinus pinaster were used for secondary metabolites, antioxidant activities, and enzymatic inhibitory activities. The amount of all measured parameters increased from 2015 to 2016 in the two pine species in the two arboreta. Pinus pinea produced more phenols and showed higher antioxidant activity and a-amylase and lipoxygenase inhibitory activities than Pinus pinaster. Besides, both species generally presented better biological activities and higher phenol amounts in 2016 than in 2015, being 2016 warmer and drier than 2015 in both harvest zones. It was evident that both species in every bioclimatic zones adapted to the new climate conditions producing more secondary metabolites that rendered better antioxidant and inhibitory enzymatic activities. These findings confirmed the impact of mid-summer water deficits on pine species in the context of climate change and help to select the most resistant species for future reforestation.

2022Journal article

Open Access

Sustainable extraction of polyphenols from vine shoots using deep eutectic solvents: influence of the solvent, vitis sp., and extraction technique

Publication . Duarte, Hugo; Aliaño-González, María José; Cantos-Villar, Emma; Faleiro, Leonor; Romano, Anabela; Medronho, Bruno

Vine shoots are the main by-products of grapevine pruning with no added value. In the present study, deep eutectic solvents (DESs) were used as alternatives to traditional chemical solvents, for the extraction of phyto chemicals from grapevine shoots. Three levulinic acid-based DESs were tested for the first time, and their per formance was compared to methanol (a standard chemical solvent) regarding the extraction of phenolic compounds from thirteen Vitis sp. shoots. Two extraction methods have been applied: ultrasound-assisted extraction and solid-liquid extraction. A total of eleven polyphenols which belongs to four families (proantho cyanins, stilbenes, hydroxycinnamic acids, and flavonols) have been identified and quantified in the extracts. The statistical analysis shows that the levulinic acid-based DES systems are novel and important alternatives to chemical solvents due to favourable eco-friendly properties and remarkable extraction performance of poly phenols. On the other hand, the ultrasound-assisted extraction technique has significantly increased the extraction rate in comparison to the solid-liquid extraction method with p-values lower than 0.05 for most compounds. The genetic factor has been shown to play an important role in the content of extracted polyphenols, being V. riparia pubescente the one that presented the highest concentrations of extracted polyphenols. Finally, the polyphenol-enriched extracts have proven important properties such as antioxidant activity and significant delay in bacteria growth against both gram-positive and gram-negative bacteria. It is important to note that, to the best of our knowledge, this is the first time that deep eutectic solvents have been used for the extraction of bioactive compounds from vine shoot residues.

2024Journal article

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