Effect of storage on bioactivity of an Algerian spice "paprika": optimization of phenolic extraction and study of antioxidant and antibacterial activities

The effect of different storage methods (ambient temperature (A), refrigeration at 4 °C (R) and freezing at - 18 °C (F)), on the phytochemistry of an Algerian spice (paprika powder), was assessed. The optimized extract was obtained under the optimum conditions of ultrasound-assisted extraction (UAE) using response surface methodology (RSM) coupled with a Box-Behnken Design (BBD). This extract was evaluated for its total phenolics content (TPC), total flavonoids content (TFC) and its antioxidant and antibacterial activities. Under the optimum conditions (5 min for the irradiation time, 40% for the amplitude, 80% for ethanol concentration and 50% for solid-liquid ratio) the TPC was 12.23 ± 1.01 mg Gallic Acid Equivalent/gram of Dried Powder (mg GAE/g DP) which is very close with experimental assay. The TPC are better preserved at A whereas TFC and the antioxidant activity at F, and the antibacterial activity depend on the storage methods and the strains tested.

Effects of the incorporation of cantaloupe pulp in yogurt: Physicochemical, phytochemical and rheological properties

The therapeutic effects of cantaloupe are of great interest for the development of functional foods such as yogurt. In this study a new dairy product has been formulated by enriching natural yogurt with fruit cantaloupe (yogurt with cantaloupe puree, yogurt with dry cantaloupe and yogurt with dry cantaloupe and cantaloupe puree). Thus, composition (moisture, ash, lipids, proteins), including amino acid contents, lactic flora as well as rheological (viscoelasticity, viscosity) property of cantaloupe yogurt and natural yogurt is assessed. In addition, pH value, water holding capacity and antioxidant activity (reducing power) are measured over refrigerated storage time. There are significant differences between natural yogurt and cantaloupe yogurt in almost all parameters. The results show that the pH decreases during the storage period and the antioxidant activity as well as the water holding capacity are more remarkable in the yogurt with dry cantaloupe at the 14th and the 28th day of storage, respectively. The addition of cantaloupe in natural yogurt ameliorates the load of lactic flora and modifies the rheological property of the new products. The results of the current study show that the addition of cantaloupe to yogurt significantly improved its quality.