Citrus peels are considered a rich source of valuable biomolecules. Pectin is a polymer of polysaccharide acid and is composed of galacturonic acid monosaccharides. In this study, response surface methodology was used to optimize pectin extraction from Citrus × clementina Hort. ex Tan. (Rutaceae) peels using citric acid as an extraction solvent. The effect of the parameters conditioning the extraction process and pectin yield (pH level, temperature, extraction time, solid/liquid ratio, and raw material particle size) was investigated using a Box–Behnken design. The quality of the extracted pectin was assessed both chemically (moisture, ash, protein, and carbohydrate content) and functionally (gelling power and emulsifying activity). According to the screening experiment, the pH level, temperature, and particle size were the main factors influencing the pectin yield. The adjusted mathematical model enabled us to plot response surfaces in order to determine the optimal extraction conditions. The highest production yield of pectin (26.6%) was obtained at the optimal conditions of pH = 1.5, temperature = 100 °C, and particle size = 0.1 mm for an extraction time of 30 min. Compared to the predicted value of 26.6%, the experimental extraction yield of C. clementina was about 21.4% of pectin. Concerning the functional properties, the extracted pectin had a high gelling power of 164 ° SAG and an emulsifying activity of 38.5%.

In Morocco, carob tree (Ceratonia siliqua L.) is of considerable socio-economic importance, helping to improve the income of rural populations and to develop the economy of mountain areas. However, the primary use of the carob’s pulp is generally limited in Morocco to animal feed. As a result, the current research suggests a novel pulp-based product designed for human consumption. The main purpose of this work is to characterize a new formulated carob beverage and assess its physicochemical, biochemical, and sensory quality. Two formulas of carob beverages were prepared with two different sugar concentrations (formula A:5 g/100 mL sugar; formula B: 10 g/100 mL sugar). Measurements of pH, titrable acidity, and colour were performed to assess the physicochemical parameters. Total polyphenols and tannins contents were determined as important functional and biochemical parameters. Regarding sensory analysis, preference test, triangle test, hedonic test, and descriptive test, were evaluated. The colour of the two formulations was dark red orange, as determined by chromameter method. For formulae A and B, the titrable acidity was (1.450±0.025) g Citric Acid Equivalent (CAE) /L and (1.450±0.031) CAE g/L, respectively, and the Brix was (11.67±0.22) °Bx and (15.33±0.22) °Bx, respectively. The polyphenols content was (98.8±0.0019) mg Gallic Acid Equivalent (GAE) /100 mL for formula A and (97.7000±0.0017) mg GAE/100 mL for formula B. The tannin level was (24.500± 0.027) mg Catechin (CE)/100 mL and (25.400±0.017) mg CE/100 mL for the formula A and formula B samples, respectively. The sensory analysis tests revealed a distinct difference between the two formulae. In fact, the formula B was highly preferred compared to formula A, also the most prominent features in the drink were colour, smell, flavour, and sweetness.

Citrus peels are known as rich source of bioactive compounds. Therefore, the establishment of an appropriate and innovative extraction method is a major interest to the food processing industry. The aim of this work is to assess the total phenolic content (TPC) and antioxidant activity (AA) of peels extracts prepared from five Moroccan clementine varieties. Extracts were prepared with microwave-assisted extraction (MAE) technique using acetone and methanol solvents. The evaluation of the antioxidant activity was performed by DPPH and ABTS- free radical scavenging. The extraction conditions had significant effects on total phenolic content (TPC) and antioxidant activity (AA). In fact, the highest TPC amount of clementine varieties (730.850±0.004mg GAE/100g DM) was obtained with acetone solvent for the Sidi Aissa variety. Regarding antioxidant activity, results with DPPH method showed an important antiradical and antioxidant activities for Sidi Aissa variety with methanol solvent (46.30± 1.01%) . However, ABTS method showed a good antioxidant activity for Ain Taoujdat with methanol solvent (3.02 mg/100g DM). This work provided to study the biochemical quality of Moroccan clementine extracts obtained by two microwave-assisted extraction processes in order to investigate further industrial potential uses in agro-food and pharmaceutical industries