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Background and aims: This study, carried out in collaboration with the research and development department of the "Cevital spa" agri-food unit, aimed to incorporate sesame oil into the formulation of two fatty food products: a frying oil and margarine to improve their physicochemical and organoleptic qualities. Methods: The sesame oil was obtained from the sesame seed by cold pressing to preserve its nutritional characteristics. The frying oil was elaborated with a mixture of three oils (sunflower, soybean, and non-roasted sesame). The margarine was enriched with 2 % of roasted sesame and then, the quality of the products was assessed. Gas chromatography (GC-FID) profile indicated that sesame oil is an oleic-linoleic rich oil with saturated fatty acid (SFA) / unsaturated fatty acid (USFA) ratio from of 0.11. Results: The organoleptic tests and physicochemical analyses, including the oil, showed that the resulting recipe is a combined oil rich in n-6 and n-9, offering an interesting ratio of MUFA /PUFA and with a SFA content of 11.49 % for an appropriate utilization in frying and cooking. Enriched margarine showed compliance with the standards set by the Codex Alimentarius and has a characteristic taste, smell and appearance, color and spread ability to the product with a sesame note. Conclusion: The results of the current study support the sesame oil supplementation to conventional frying oil and to commercial margarine. Sesame oil may therefore be an alternative source of fatty acids that could contribute to the diversification of combined oils.

Background: In Algeria, important quantities of secondary date variety (Phoenix dactylifera L.) are generated in each campaign; their chemical composition is similar to that of commercial dates. The present work aims to valorize this common date variety (Degla-beida) which is often poorly exploited. Methods: In this context, we tried to prepare syrup from the secondary date variety and evaluate the effect of conventional extraction (CE) or water bath extraction (WBE) and alternative extraction (microwaves assisted extraction (MAE) and ultrasound-assisted extraction (UAE)) on its total sugar content (TSC), using response surface methodology (RSM). Then, the analysis of individual sugars was performed by high performance liquid chromatography (HPLC). Results: Maximum predicted TSC recoveries under the optimized conditions for MAE, UAE and CE were 233.248 ± 3.594 g/l, 202.889 ± 5.797 g/l and 233.535 ± 5.412 g/l, respectively, which were close to the experimental values: 233.796 ± 1.898 g/l; 202.037 ± 3.401 g/l and 234.380 ± 2.425 g/l. HPLC analysis revealed high similarity in the sugar composition of date juices obtained by MAE (60.11% sucrose, 16.64% glucose and 23.25% fructose) and CE (50.78% sucrose, 20.67% glucose and 28.55% fructose), although a large difference was detected for that obtained by UAE (0.00% sucrose, 46.94% glucose and 53.06% fructose). Conclusion: Microwave-assisted extraction was the best method for the preparation of date syrup with an optimal recovery of total sugar content. However, ultrasound-assisted extraction was the best one for the preparation of date syrup with high content of reducing sugars.

Soybean oil is the most consumed oil worldwide due to its cheapness but presented a weak thermo-resistance due to its richness in poly-unsaturated fatty acids. This study aims to improve the thermo-stability of refined soybean oil by blending it with some cold-pressed oils. For this, cold-pressed and soybean oils were firstly characterized (K232, K270, acidity, peroxide value, iodine value, induction time, phenolic contents, and antioxidant activity). Then, binary blends of each cold-pressed oil (30%) with soybean oil (70%) were analyzed before and after heat treatment (170 °C for 10 h/day for 5 days) followed by the application of the simplex lattice mixture design in order to optimize the combination of the three best cold-pressed oils. The changes in fatty acid profiles were assessed by gas chromatography (GC-FID). The results revealed that soybean oil presented the best physicochemical traits, while cold-pressed oils expressed high levels of phenolic contents and antioxidant activities. From the six binary oil blends, soybean oil mixed with lentisk, sesame, or almond oils were selected for their best thermo-stability. The simplex lattice mixture design, applied for these three chosen oils, indicated that the combination of soybean oil (70%) with lentisk and sesame oils (17.7 and 12.3%, respectively) was considered the optimal blend that gives the maximal thermo-stability improvement to soybean oil. GC-FID analysis showed that fatty acids, particularly linoleic and linolenic acids, were more conserved after heat-treatment in optimal oils blend than soybean oil. This study clearly demonstrated that lentisk and sesame oils enhanced the thermo-resistance of soybean oil, and the findings of this study could be used as an integrated model in oil and fat industries.

Grapefruit (Citrus × paradisi, Algerian variety) essential oil obtained by hydro‐distillation was evaluated as a substitute for vitamin E for margarine. The obtained IC₅₀ values were: 39.92 ± 0.18, 15.09 ± 0.02, and 4.42 ± 0.03 mg/ml by the 2,2‐diphenyl‐1‐picrylhydrazyl method, the reducing power and the β‐carotene/linoleic acid tests, respectively. These results were higher compared to those of the synthetic antioxidants. Values for BHA in DPPH and β‐carotene/linoleic acid assays were 0.158 ± 0.003 and 0.032 ± 0.000 mg/ml, respectively. The result of ascorbic acid for reducing power was 0.053 ± 0.001 mg/ml. Analysis of composition showed 128 volatile compounds. The limonene was the major compound (67.22%) followed by trans‐citral (5.39%) and isoauraptene (2.85%). All samples were fortified with 12.5, 50 and 100 µg/g of essential oil. The Rancimat test demonstrated that the lowest concentration of essential oil gave the best resistance to oxidation (22.6 hr). NOVELTY IMPACT STATEMENT: Grapefruit essential oil was used as a substitute for vitamin E for margarine, and it gave better resistance to oxidation than control samples. The presented solution could be successfully applied on an industrial scale.

BACKGROUND: Margarine is a widely consumed product in Algeria. Few or no studies have been conducted to estimate its safety and nutritional quality. OBJECTIVES: This study aims to evaluate some algerian margarines. Particular interest is given to their oxidative stability and fatty acid composition. METHODS: Twelve margarines are selected, including tub and stick margarines, puff pastry margarines and vegetable smen. We evaluate physicochemical parameters (water content, pH, salt content, melting point and solids content with RMN), oxydative stability with Rancimat and fatty acid composition with GLC. RESULTS: The analyzed products are mostly in conformity with standards. The estimation of the oxidative stability revealed that tub margarines are the least stable. Fatty acid composition showed that practically all the analyzed products are rich in SFA. CONCLUSION: Large amounts of highly saturated oils such as palm oil, coconut and palm kernel are used. The fact that the trans fatty acids content is not very high in Algerian margarines and vegetable smen is not due to the legislation applied but to the awareness of few industries and especially to the import price exerted on different types of fat. So it is in view of profitability that industries choose raw material and not in a health concern.

This study was designed within the scope of industrial exploitation of antioxidant extracts from Hibiscus sabdariffa. Efficiency in the extraction of antioxidants (total phenolics, flavonoids and anthocyanins) from calyces was assessed through different processes involving solvents (water, 80% acetone and 80% methanol), microwaves and ultrasounds. Results indicated that microwave extraction with 80% acetone gave the highest yield for total phenolics, expressed as gallic acid equivalents (GAE) per g dry weight (DW) (3.73 GAE/100 g DW), while the highest results for total flavonoids and anthocyanins were found in the microwaved aqueous extracts. Antioxidant activity of the extracts reported the highest reducing power for aqueous extracts with microwave extraction, while 80% acetone and methanol samples exhibited the highest antioxidant activity by high-performance thin-layer chromatography (HPTLC) and 2,2-diphenyl-1-picrylhydrazyl (DPPH) reagent. HPTLC performed for screening of phenolic compounds revealed the occurrence of anthocyanins in dimer-like bands. Laboratory tests showed high protection against lipid oxidation of the whey spread emulsion (22.32 h) incorporated with the sonicated aqueous extract. Results of peptide sequencing data by liquid chromatography electrospray ionization tandem mass spectrometry (LC-ESI-MS/MS), after sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) analysis, revealed protein–polyphenols interactions by the formation of dimers between polyphenols and protein/peptides. These interactions were found without effect on the oxidative stability of the emulsions. These study suggest that H. sabdariffa’s calyces have the potential to be used like food antioxidants.

International audience; This study falls within the framework of the industrial exploitation of by-products of the prickly pear (Opuntia ficus-indica). The study aims to evaluate the use of hydro-ethanolic extract of prickly pear peels as a substitute of vitamin E used as antioxidant in margarine preservation. The extract was rich in total phenolics (1512.58 mg GAE/100 g DM). HPLC-DAD-ESI-MSn analyses allowed the identification of sixteen compounds belonging to hydroxybenzoic acids, hydroxycinnamic acids and flavonoids. The extract displayed a reducing power and an antiradical activity that were respectively similar to and lower than the two antioxidant standards quercetin and butylated hydroxyanisole. Tests conducted at laboratory and pilot scales showed that the margarines elaborated with peel extract were more resistant to oxidation than the margarine reference with vitamin E. In addition, neither the physicochemical nor the microbiological properties were modified. Prickly pear peels contain bioactive substances that could be used in different food sectors.