Comparative chemical composition and antioxidant activity of olive leaves Olea europaea L. of Tunisian and Algerian varieties.

The main objective of this research was to understand the effect of different solvents (ethanol, ethyl acetate, and hexane) on the extraction of bioactive compounds in addition to the antioxidant activity of eight Tunisian and Algerian olive leaf (Olea europaea L) cultivars. The different extracts were evaluated for their content of total phenols, flavonoids, and condensed tannins. The antioxidant capacity was determined by ABTS (2,2-azinobis (3 ethylbenzothiazoline-6-sulfonic acid) and DPPH (2,2-diphenyl-1 picrylhydrazyl) methods. In addition, qualitative and quantitative analyses of phenolic compounds by HPLC were performed. In terms of phenolic content, ethanol was found to be the best solvent to extract phenolic compounds with antioxidant capacity. The ethanolic extract of Sigoise and Rougette varieties were the richest in total phenols 161.54 ± 0.99, and 160.53 ± 1.17 mg GAE/g DE respectively. The highest levels of flavonoids were detected in ethyl acetate extracts of Rougette (87.58 ± 6.99 mg QE/g DE) and Verdal varieties (86.77 ± 1.75 mg QE/g DE), whereas the hexanolic extracts of Gerboui, Sofiana, and Chemlali exhibited the higher amount of tannins (67.99 ± 5.41, 65.52 ± 1.94, 64.64 ± 1.51 mg CE/g DE, respectively). Furthermore, in the DPPH radical scavenging activity assay, the Sofiana extract exhibited the highest antioxidant activity (23.85 ± 0.58 mg/L). In another case, for the ABTS radical scavenging assay, the Verdal extract showed high antioxidant potential (30.22 ± 1.35 mg/L). HPLC analysis of ethanolic extracts of the different varieties allowed the identification of 19 organic compounds, with oleuropein (2604.01-7991.14 mg/100g DM) being the most abundant, followed by hydroxytyrosol (250.74-687.54 mg/100g DM) and verbascoside (216.12-672.64 mg/100g DM) being the major compounds in the olive leaves in all studied ethanolic extracts, with concentrations varying significantly according to the cultivars and geographical origin. Principal component analysis (PCA) performed on phenolic profiles and antioxidant activities revealed the influence of bioactive compounds on antioxidant activity, with high concentrations of phenols and flavonoids in olive leaf extracts having a strong antioxidant activity.

Formulation of pasta enriched with protein-rich lupine (Lupinus mutabilis Sweet) and wheat bran using mixture design approach.

In recent years, as awareness of healthy diets has increased, consumers are becoming more aware of their food and are paying more attention to their diet. Nutritionists have recommended an increased consumption of dietary fiber in the daily diet to improve health. Within this context, this work aims to formulate "spaghetti" pasta enriched with lupin flour and wheat bran. For the formulation of the mixture of those flours, we used the NemrodW software to predict the optimal pasta formula. A physicochemical characterization, as well as the culinary quality of the pasta resulting from the different mixtures, was carried out to model each significant criterion and choose the optimal mixture that will be used in the pasta recipe. The evaluation of the physicochemical characteristics of the pasta showed that the addition of lupin flour and bran resulted in an improvement in the nutritional value of the enriched spaghetti. Following the results obtained, the software proposed an optimal mix and will be used for further study. This formula comprises 19.60% bran, 27.83% lupin flour, and 52.75% durum wheat semolina. The caloric value of the dough from the optimal mix was determined and compared to that of the standard dough. The results of our study indicated a significant improvement in the nutritional value of the enriched pasta compared to the standard pasta. The enriched pasta contained higher levels of protein, ash, lipids, polyphenols, and pigments and lower levels of sugars, which make it a more nutritious option for certain individuals, such as athletes or those following a protein or low-sugar diet. PRACTICAL APPLICATION: The proposed method of substituting wheat semolina with lupine flour and wheat bran in spaghetti formulation has demonstrated a potential for producing protein-rich and nutritionally enriched pasta. This approach can be useful for developing similar functional food products that cater to the dietary requirements of athletes or individuals following a protein or low-sugar diet.

Optimization of antioxidant and lycopene extraction from tomato pomace using Hansen solubility parameters and its application in chicken meat preservation.

Tomato pomace, composed of peels and seeds, is often discarded or used as animal feed. However, it contains valuable phytochemicals, including lycopene. Lycopene, a natural pigment, is an antioxidant known for reducing the risk of chronic diseases like cardiovascular ailments and cancer. In this study, we aimed to study the possibility of valorizing tomato pomace by quantifying phenolic compounds, evaluating the antioxidant activity of their extracts, as well as extracting and quantifying lycopene, and studying the effect of tomato peel extract on the oxidative stability of chicken patties during storage. The effectiveness of different solvent mixtures for the extraction of lycopene was evaluated using Hansen solubility parameters (HSPs). The obtained results showed that the best solvent mixture was hexane/acetone (50/50) with a Hansen theoretical distance of 7.2, indicating its favorable solvation power. It also achieved a notable extraction yield of 3.12% and the highest lycopene yield of 20.05 mg/100 g. This combination demonstrated the highest values in terms of total phenolic (24.06 mg equivalent gallic acid/100 g dry matter) and flavonoid content (30.55 mg equivalent catechin/100 g dry matter), indicating a significant presence of these compounds. However, its 1,1-diphenyl-2-picrylhydrazyl (13.51 µg/mL) and ABTS, 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid, (8.52 µg/mL) IC50 values were comparatively lower than the other mixes. The use of this fraction as a food additive and antioxidant showed significant competitiveness with the conventional preservative, 2,6-di-tert-butyl-4-methylphenol. Tomato extract can be considered a potential natural preservative in food preparations due to its high lycopene content. PRACTICAL APPLICATION: This research provides valuable insights into optimizing the extraction of antioxidants from tomato pomace, using HSPs. The findings have the potential to benefit the food industry by developing improved methods for preserving chicken meat through the application of these optimized antioxidant extracts. By enhancing the preservation process, this study may contribute to extending the shelf life and maintaining the quality of chicken meat, leading to reduced food waste and improved consumer satisfaction.

Polyphenol composition and antioxidant activity of cumin (Cuminum cyminum L.) seed extract under drought.

This research evaluated the effect of drought on total and individual polyphenol contents as well as the antioxidant activities of cumin (Cuminum cyminum L.) seeds of 2 geographic origins, Tunisia (TCS) and India (ICS). Plants were treated with different levels of water deficit: control. Our results indicated that, in both varieties, moderate water deficit (MWD) improved the number of umbels per plant as well as the number of umbellets per umbel and the seed yield, in comparison to the control, but it decreased under severe water deficit (SWD). Besides, total phenolic contents were higher in the treated seeds and drought increased the level of total and individual polyphenols. This increase was appreciably more important in TCS than in ICS. Moreover, antioxidant activities of the extracts were determined by 4 different test systems, namely 2,2-diphenyl-1-picrylhydrazyl, ß-carotene/linoleic acid chelating, and reducing power assays, and showed that treated seeds exhibited the highest activity, for both TCS and ICS.

Thermal stability of corn oil flavoured with Thymus capitatus under heating and deep-frying conditions.

BACKGROUND: The thermal stability of corn oil flavoured with thyme flowers was determined and compared with that of the original refined corn oil (control). The oxidative stability index (OSI) was measured and samples were exposed to heating (30 min at 150, 180 and 200 °C) and deep-frying (180 °C). Changes in peroxide value (PV), free fatty acid (FFA) content, specific absorptivity values (K(232) and K(270)), colour and chlorophyll, carotenoid and total phenol contents were monitored. RESULTS: The OSI and heating results showed that thyme incorporation was effective against thermal oxidation based on the increased induction time observed for the flavoured oil (6.48 vs 4.36 h), which was characterised by lower PV, FFA content, K(232) and K(270) than the control oil after heating from 25 to 200 °C, with higher red and yellow colour intensities and chlorophyll, carotenoid and total phenol contents. The deep-frying test showed the accelerated deterioration of both oils in the presence of French fries. CONCLUSION: Compared with the control oil, the thyme-flavoured oil showed improved thermal stability after heating. This could be attributed to the presence of thyme pigments and antioxidant compounds allowing extended oil thermal resistance.