Maceration and liquid-liquid extractions of phenolic compounds and antioxidants from Algerian olive oil mill wastewater

Improving stability of frying oils and food quality with addition of dried olive mill wastewater

The olive oil industry in Mediterranean countries generates large quantities of waste, recognized as a cheap source of valuable compounds. This study evaluated the antioxidant properties, nutritional value and antimicrobial activity of dried olive mill wastewater (OMWW) and its effect on vegetable oils (corn and soybean) during frying and selected food products. OMWW was found to contain 5.75 g GAE/L of free phenols, with oleuropein being the most bioactive compounds. Refined vegetable oils enriched with OMWW (600 mg/L) showed an increase in induction times, indicating higher oxidative stability compared to oils with BHT. Sensory evaluation revealed no significant differences (p < 0.05) in characteristics of French fries which fried in enriched refined oils versus controls. OMWW polyphenols effectively retarded lipid oxidation and improved oxidative stability of oils, nutritional value of French fries, and sensory attribute of mayonnaise. Beneficial use of OMWW as a natural antioxidant was recommended by the present study.

Non-targeted analysis and suspect screening of organic contaminants in temperate snowfall using liquid chromatography high-resolution mass spectrometry

Contaminants released into the atmosphere that undergo regional and long-range transport can deposit back to Earth through snowfall. When snow melts, these contaminants re-enter the environment, sometimes far from their original emission sources. Here we present the first comprehensive characterization of organic contaminants in snow from North America. Fresh snowfall samples were collected in the central United States over a three-year period and measured by liquid chromatography high-resolution mass spectrometry for suspect screening and non-targeted analysis. The resulting data set was screened against experimental MS/MS libraries and underwent supplemental in silico MS/MS analysis. In total, 91 possible compounds were tentatively identified in snow, and 17 were successfully confirmed and semi-quantified with reference standards. These contaminants were mostly anthropogenic in origin and included six herbicides, three insect repellants, one insecticide metabolite, and one fungicide. The most prominent compounds present in all samples were N-cyclohexylformamide (known contaminant in tire leachate), DEET (insect repellent), and dimethyl phthalate (plasticizer), with median deposition fluxes of 4032, 284, and 262 ng m-2, respectively. Three additional compounds were detected in 100% of samples: coumarin (phytochemical and fragrance additive), 5-methylbenzotriazole (antifreeze component), and quinoline (heterocyclic aromatic). The Peto-Peto test revealed statistically significant differences in deposition fluxes for these six contaminants (p < 0.05), with weak but statistically significant positive associations between coumarin and DEET and between coumarin and quinoline according to a Kendall's tau correlation analysis. These findings demonstrate the utility of in silico analysis to complement MS/MS matching with experimental databases. Even so, thousands of unidentified features remained in the data set, highlighting the limitations of current strategies in non-targeted analysis of environmental samples.

Exploring the Phytochemical Composition and the Bioactive Properties of Malbec and Torrontés Wine Pomaces from the Calchaquíes Valleys (Argentina) for Their Sustainable Exploitation

Hydroalcoholic extracts from Malbec and Torrontés wine pomaces (Vitis vinifera L.) originating from the high-altitude vineyards of Argentina's Calchaquí Valleys were characterized. Total phenolics, hydroxycinnamic acids, orthodiphenols, anthocyanins, non-flavonoid phenolics, total flavonoids, flavones/flavonols, flavanones/dihydroflavonols, and tannins were quantified through spectrophotometric methods, with the Malbec extract exhibiting higher concentrations in most of phytochemical groups when compared to Torrontés. HPLC-DAD identified more than 30 phenolic compounds in both extracts. Malbec displayed superior antiradical activity (ABTS cation, nitric oxide, and superoxide anion radicals), reduction power (iron, copper, and phosphomolybdenum), hypochlorite scavenging, and iron chelating ability compared to Torrontés. The cytotoxicity assessments revealed that Torrontés affected the viability of HT29-MTX and Caco-2 colon cancer cells by 70% and 50%, respectively, at the highest tested concentration (1 mg/mL). At the same time, both extracts did not demonstrate acute toxicity in Artemia salina or in red blood cell assays at 500 µg/mL. Both extracts inhibited the lipoxygenase enzyme (IC50: 154.7 and 784.7 µg/mL for Malbec and Torrontés), with Malbec also reducing the tyrosinase activity (IC50: 89.9 µg/mL), and neither inhibited the xanthine oxidase. The substantial phenolic content and diverse biological activities in the Calchaquí Valleys' pomaces underline their potentialities to be valorized for pharmaceutical, cosmetic, and food industries.

Understanding the adsorption of Reactive red 2 onto metal hydroxide sludge: analysis with physico-statistical steric and energetic perspectives

This theoretical investigation delves into the analysis of Reactive red 2 (RR-2) adsorption isotherms on metal hydroxide employing a sophisticated double-layer model characterized by dual-energy levels within the realm of physical adsorption phenomena. An examination of five distinct statistical physics frameworks was undertaken to elucidate the modeling and interpretation of equilibrium data. Expression for the physico-chemical parameters involved in the adsorption phenomena was derived based on statistical physics treatment. Fitting experimental adsorption isotherms (308-333 K) to a DAMTBS has revealed the number of anchored molecules per site, occupied receptor site density, and the number of adsorbed layers. The steric parameter n varies between 0.92 and 1.05. More importantly, it is evidenced that the adhesion mechanism of (RR-2) onto metal hydroxide as determined by the estimated adsorption energies (< 40 kJ/mol) supports a spontaneous and exothermic physisorption process. Thermodynamic potential functions such as entropy, Gibbs free energy, and internal energy have been computed based on the most suitable model. This research advances our physical understanding of how metal hydroxide captures dye molecules RR-2 through adsorption reaction for water depollution treatment.

Olive oil industry: a review of waste stream composition, environmental impacts, and energy valorization paths

The olive oil production is a key economic sector for the producing countries, mainly in the Mediterranean region. However, the worldwide increasing oil production led to the generation of huge amounts of wastes detrimental for the environment. Therefore, efficient and sustainable management of olive industry wastes has recently acquired significant interest in the scientific research community. In the actual world energy context, various studies dealt with the valorization of the solid/liquid waste streams obtained from the discontinuous/continuous extraction of olive oil for energy purposes. The application of waste-to-energy treatments to these effluents can turn them out into an important energy resource. This review article presents the main used oil extraction techniques and their related research developments. The characterization of the generated wastes and the factors behind their bad environmental impacts are highlighted. Relevant research works related to biochemical and thermochemical conversion of olive mill wastes are extensively reviewed and discussed in terms of product yields and composition. A recent update of the studies addressing olive industry waste applications for energy production is also given. This investigation revealed a lack of studies in relation to the hydrothermal processing of olive mill wastes. Despite their suitability for this process (e.g., high moisture content), few papers have investigated the hydrothermal conversion of these waste streams. This scientific gap opens a very interesting research direction, which has to be further investigated.