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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.

A new Rhizopus oryzae strain FSIS4 isolated from wheat seed cultivated in Algerian Sahara was evaluated for the production of a thermostable α-amylase enzyme. Medium components were optimized by a statistical approach for the optimal production of α-amylase using an agro-industrial residue (decommissioned dates). The Plackett–Burman design was performed to screen the fermentation variables and response surface methodology for optimizing the significant factors affecting the production. The optimum levels for maximum production of α-amylase (approx 10,151 IU) were determined. A 1.8-fold increase of production was obtained in comparison to the non optimized medium. Partial characterization of the enzyme showed optimal temperature and pH at 60 °C and 5.0, respectively. The enzyme was found to be stable at 80 and 90 °C, with a half-life of 165 and 105 min, respectively. According to the large literature, this is the first report on the production of α-amylase by the thermophilic R. oryzae strain FSIS4. The thermo and pH stability of the α-amylase suggest its wide application in the food and pharmaceutical industries.

Khliaa Ezir is a traditional and popular meat product, which is produced from whole beef, camel, goat or lamb meat. It is an Algerian and a ready to eat meat product that is marinated, cooked and ripened. The product is for numerous months preserved in an earthenware jar at room temperature. Microbiological investigation on Khliaa Ezir during preparation is a prerequisite and to our knowledge, this is the first study, which provide its preliminary microbiological characterization. Thus, the aim of the present work is to study the evolution of the microflora and microbiological safety of Khliaa Ezir during the main traditional preparation steps. The microbiological counts indicated that Lactic Acid Bacteria (LAB) are the most abundant in the product, namely during the repining and storage period. However, total Coliforms were very low in fresh beef, being eliminated after 3 days of curing. Yeasts and Molds were the highest in fresh beef, and then disappeared after cooking and during the ripening and storage step. None of the pathogenic flora during the whole preparation steps were detected. We think that the cooking temperature applied during thermal treatment (80°C) contributed to the high hygienic quality of Khliaa Ezir. On another hand, a significant increase in pH was observed during the storage period to achieve a final pH of 6.19 ± 0.01 at 30 days of storage.

International audience; Khliaa Ezir is a typical Algerian meat product, prepared according to a traditional process based on empirical observations and traditional recipes, consisting of steps of trimming, marinating, cooking, ripening and ageing in earthenware jar (Ezir). Understanding the biological mechanisms behind the development of the sensory properties of this cultural product is of great interest for eventual product marketing. The aim of the present study was first a preliminary proteomic characterization of myofibrillar and sarcoplasmic protein extracts of the product during preparation, ripening and ageing in earthenware jar. A comparison of the proteome of the two extracts at different days and steps was carried out with 1-DE electrophoresis, showing quantitative difference in several bands. Some bands might be potential markers of the proteolysis that takes place during the preparation steps, especially during marinating and ripening. This first and preliminary proteomic data from both myofibrillar and sarcoplasmic protein extracts of Khliaa Ezir are consistent with a differential release of specific proteins as a function of preparation step.

A new thermostable α-amylase from Rhizopus oryzae FSIS4 was purified for first time and recovered in a single step using a three-phase partitioning (TPP) system. The fungal α-amylase, at a concentration of 1.936 U per kg of flour, was used in bread-making and compared to the commercial enzyme. The results showed a significant effect of the recovered α-amylase in the prepared bread and allowed us to improve the quality of the bread. The study indicated clearly that the recovered α-amylase is a potential candidate for future applications in the bread-making industry and in other food biotechnology applications.

A rapid overview of the Three Phase Partitioning (TPP) system as an efficient non-chromatographic tool is given. This elegant non-chromatographic tool is able to purify numerous proteins and especially proteases in a one step protocol. TPP is able to do not only purify proteins, but also concentrate them into one of the phases and enhance their proteolytic activity. The application of TPP for the extraction and purification of plant milk-clotting enzymes and meat tenderizers agents are given. In addition, some proteases from other materials are summarized. This short communication stress showed that TPP is a simple, economical and quick method for proteases recovery from plant proteases. This elegant non-chromatographic tool may be performed in a purification process to be used successfully in food industries, namely to provide enzymes for cheese-making and meat tenderizing.