Percorrer por autor "Tarchoun, Neji"
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- Evaluation of the potential preservative capacity of pumpkin (Cucurbita maxima Duchesne) by-productsPublication . Leichtweis, Maria Gabriela; Molina, Adriana K.; Pereira, Carla; Pires, Tânia C.S.P.; Calhelha, Ricardo C.; Tarchoun, Neji; Oliveira, Beatriz; Ferreira, Isabel C.F.R.; Barros, LillianLarge amounts of fruits and vegetables are lost or wasted along the food supply chain. This occurs at the harvest level, for not meeting the sales standard, in the failure of transport and logistics, at the household, due to underutilization and discards, and many others.¹ A considerable portion of this waste generation is from the food processing industry, which has different leftovers such as peels, seeds, bagasse, leaves, fibers, and stalk, that are generally not recovered for reuse. Despite little explored and with low commercial value, these bioresidues and by-products have been shown to contain important high value-added compounds². These compounds, such as polyphenols, alkaloids, flavonoids, carotenoids, etc., are originated in the secondary metabolism of the plant, therefore generally presenting bioactive and functional proprieties. The potential of recovery of these compounds and their application in foodstuff as natural additives has been increasingly demonstrated in the literature³. The present word proposed to evaluate the by-products obtained in the pumpkin industrial processing as a source of preservative compounds. Pumpkin seeds are consumed as snack in some regions; however, this part of the fruit, as well as the peel and fibers, are poorly utilized, being a cheap and promising matrix to be explored. In this sense, the by-products of pumpkins cultivated in Tunisia were evaluated for their bioactive properties, more specifically, in terms of preservative capacity. For that purpose, the hydroethanolic extracts of the peel and the mix of seeds and fibers from the “Batati”, “Karkoubi”, and “Bejaoui” varieties were assessed. For the antioxidant activity evaluation, the cell-based method of the inhibition of lipid peroxidation (TBARS) was applied. The antibacterial and antifungal activity was tested against 10 microorganisms of interest in food preservation. Moreover, non-tumor cells of a primary culture of porcine liver (PLP2) were used to assess the cytotoxicity, through the sulforhodamine B (SRB) colorimetric assay. Through this study, all the samples presented great preservative potential, since they protected at least 5 of the 10 tested strains of microorganisms, such as Aspergillus brasiliensis, Staphylococcus aureus, Escherichia coli, Salmonella 5 enterocolitica, and Yersinia enterocolitica, in concentrations up to 10 mg/mL, and showed great antioxidant results, reaching values about just 2 times higher than the positive control Trolox. The highest antioxidant activity was presented by the seeds and fibers of “Karkoubi” and “Bejaoui”, while for the “Batati” variety, the results were quite similar between the peel and the mix of seeds and fibers. Regarding the antimicrobial activity, the peel presented better results than the seeds and fibers in the antibacterial assay, and the opposite was noticed in the antifungal evaluation. All the mix samples protected against the 2 tested strains of fungi, the peel of “Batati”and of “Karkoubi” inhibited 6 of 8 bacterial strains, and none of the samples presented bactericidal nor fungicidal effect. Furthermore, the safety of food application of the samples was verified by the absence of toxicity in the primary culture of non-tumor porcine liver cells (PLP2), at the maximum concentration tested (400 μg/mL).These results corroborate the purpose of valuing pumpkin by-products as a source of natural preservative compounds with interest for application in food products, thus promoting the replacement of synthetic additives by a natural alternative obtained from underexplored matrices.
- Improved recovery of antioxidant compounds from refined pumpkin peel extract: a mixture design method approachPublication . Mansour, Rim Ben; Falleh, Hanen; Nefzi, Nermine; Dakhlaoui, Sarra; Selmi, Sawssen; Hammami, Majdi; Barros, Lillian; Petropoulos, Spyridon Α.; Tarchoun, Neji; Ksouri, RiadhThis study employed the mixture design method to determine optimal solvent combinations, aiming to obtain refined extracts from squash peels with enhanced antioxidant properties. We optimized extraction solvents, focusing on recovering the total phenolic compounds (TPC) and increased antioxidant properties using a second-order polynomial equation through the response surface methodology (RSM). Six solvents (MeOH, Hexane, DCM, EtOAc, BuOH, and water) were assessed for their effects on TPC and antioxidant activity in preliminary experiments. The refined extracts underwent a HPLC analysis for a phenolic composition determination and were further evaluated for their antibacterial activity and cytotoxicity. The results revealed a rich phenolic content in the refined extract from peels of Bejaoui landrace, primarily catechin (8.06 mg/g dry extract (DE)), followed by epicatechin and kaempferol (5 mg/g DE). Antibacterial tests against Enterococcus faecalis, Pseudomonas aeruginosa, Salmonella typhimurium, and Staphylococcus aureus showed significant antimicrobial activities, especially for Karkoubi and batati landraces, where the growth inhibitions were 99%, 96%, 97%, and 80% and 94%, 89%, 98%, and 96% for the respective bacteria. The peel extracts exhibited a negligible cytotoxicity on the RAW264.7 cell line, even at high concentrations. Our findings emphasize the potential antioxidant and antibacterial properties of peel extracts due to diverse phenolic compounds, suggesting the potential use of squash peels in the food and nutraceuticals industries as sources of natural antimicrobial agents.
- Optimizing the encapsulation of the refined extract of squash peels for functional food applications: A sustainable approach to reduce food wastePublication . Mansour, Rim Ben; Falleh, Hanen; Hammami, Majdi; Hadid, Feriel Ben; Barros, Lillian; Tarchoun, Neji; Petropoulos, Spyridon; Ksouri, RiadhEncapsulation of the refined extract from squash fruit peels was evaluated for the design of functional foods with beneficial effects on human health. The percentage of maltodextrin and gum Arabic in the wall material as well as the concentration of the refined extract were the independent variables for the Box Behnken design, and their impact on response variables (total phenolic compound [TPC] content, DPPH activity, the size of particles, and polydispersity index [Pdi]) was evaluated. The obtained emulsions were compared based on their TPC content, as well as their antioxidant activities. Optimum conditions were as follows: maltodextrin percentage of 23.8%, gum Arabic percentage of 27.7%, and phenolic extract percentage of 48.5%. Under these conditions, the response variables were the following: TPC content of 46.01 mg of gallic acid equivalent per gram of extract (mg GAE/g of E); DPPH inhibition percentage of 64.85% at 1 mg/mL, particle size of 571.22 nm, and Pdi of 0.46. Once the emulsion was optimized, we tried to define the combination of variables that produced microcapsules with the highest TPC content and the highest antioxidant activity. Physicochemical parameters and biological activities were also assessed. Microcapsule parameters were a pH of 4.2, a viscosity of 17 mPa/s, and a turbidity of 0.412 NTU (Nephelometric Turbidity Units), and color measurements were L = 102.4, a = 3.5, and b = 7.8. Indeed, the TPC content was 37.2 mg GAE/g dried residue and antiradical activity against DPPH was 44.2%. The inhibitory effects of the optimized emulsion on Enterococcus faecalis, Pseudomonas aeruginosa, Salmonella typhimurium, and Staphylococcus aureus were investigated, and the results indicated the highest sensitivity (89% inhibition) for S. typhimurium. Our results indicate the efficiency of the optimized emulsification process for developing microcapsules of high quality as well as the potential of using them in the development of novel food and pharmaceutical products.
- Subprodutos de abóbora como fonte de conservantes naturais para aplicação alimentarPublication . Leichtweis, Maria Gabriela; Molina, Adriana K.; Pereira, Carla; Pires, Tânia C.S.P.; Calhelha, Ricardo C.; Tarchoun, Neji; Oliveira, Beatriz; Ferreira, Isabel C.F.R.; Barros, LillianAtendendo à problemática da crescente produção de resíduos alimentares industriais, este trabalho teve como objetivo analisar os subprodutos da abóbora como uma fonte promissora e economicamente acessível de conservantes naturais. Os extratos da casca (C) e da mistura de sementes e fibras (MSF) das variedades ‘Batati’, ‘Karkoubi’ e ‘Bejaoui’ foram avaliados quanto à sua atividade antioxidante, através do método da inibição da peroxidação lipídica (TBARS); actividade antimicrobiana contra dez estirpes diferentes de microrganismos de interesse na conservação de alimentos; e citotoxicidade, através do ensaio colorimétrico da sulforrodamina B numa cultura primária de células de fígado de porco (PLP2). Todas as amostras apresentaram uma excelente capacidade antioxidante, especialmente as MSF das variedades ‘Karkoubi’ e ‘Bejaoui’. Em termos de atividade antimicrobiana, as C apresentaram melhor capacidade antibacteriana que as MSF; no entanto, estas últimas revelaram uma maior capacidade antifúngica nas duas estirpes testadas. As C de ‘Batati’ e ‘Karkoubi’ inibiram seis das oito estirpes bacterianas estudadas e nenhuma das amostras apresentou efeito bactericida ou fungicida. Além disso, nenhuma das amostras apresentou toxicidade na cultura de células hepáticas (concentração ≤ 400 μg/mL), o que demonstra a sua segurança para aplicação alimentar. Estes resultados corroboram a importância da valorização dos subprodutos da abóbora para a obtenção de conservantes de base natural.
- The use of response surface methodology to optimize assisted extraction of bioactive compounds from Cucurbita maxima fruit by-productsPublication . Ben Mansour, Rim; Falleh, Hanen; Hammami, Majdi; Barros, Lillian; Petropoulos, Spyridon Α.; Tarchoun, Neji; Ksouri, RiadhThis work aimed to optimize the extraction conditions of bioactive compounds obtained from three squash by-products (e.g., peel, endocarp, and seeds) using the response surface methodology (RSM). The selected independent variables were ethanol concentration, extraction time, and extraction temperature. Squash by-products' bioactive molecules were extracted according to the matrix proposed by the experimental plan. Significant variability in total phenolic compound content (TPC) and antioxidant activity, depending on the extraction time, the solvent concentration, and the extraction temperature, was recorded for the tested by-products. The experimental results adequately fitted with second-order polynomial models and showed significant linear, quadratic, and interaction effects of the independent variables. Data analysis suggested that the optimal extraction conditions were 12.2% ethanol for 11.2 min at 55 & DEG;C for peels; 28.5% ethanol for 10.5 min at 37 & DEG;C for endocarp; and 20% ethanol for 10.5 min at 60 & DEG;C for seeds. The results obtained showed that the experimental and predicted values of TPC and antioxidant activities as an indicator of a successful extraction fit with each other, thus indicating the optimal extraction conditions. Under these conditions, the obtained extracts exhibited high, although variable, TPC with epicatechin and epigallocatechin as major compounds, as well significant antimicrobial potency, which reached 100% and 80% inhibition of the tested bacteria and fungi.