Effect of Gum Arabic from Acacia senegal var. kerensis as an Improver on the Rheological Properties of Wheat Flour Dough

Dough improvers are substances with functional characteristics used in baking industry to enhance dough properties. Currently, the baking industry is faced with increasing demand for natural ingredients owing to increasing consumer awareness, thus contributing to the rising demand for natural hydrocolloids. Gum Arabic from Acacia senegal var. kerensis is a natural gum exhibiting excellent water binding and emulsification capacity. However, very little is reported on how it affects the rheological properties of wheat dough. The aim of this study was therefore, to determine the rheological properties of wheat dough with partial additions of gum Arabic as an improver. Six treatments were analyzed comprising of: flour-gum blends prepared by adding gum Arabic to wheat flour at different levels (1%, 2% and 3%), plain wheat flour (negative control), commercial bread flour and commercial chapati flour (positive controls). The rheological properties were determined using Brabender Farinograph, Brabender Extensograph and Brabender Viscograph. Results showed that addition of gum Arabic significantly (p chapati. These findings support the need to utilize gum Arabic from Acacia senegal var. kerensis as a dough improver.

Development of a Protein-Rich Ready-to-Eat Extruded Snack from a Composite Blend of Rice, Sorghum and Soybean Flour

Extrusion cooking is an ideal method for the manufacture ready-to-eat snacks. The benefits include increased protein and starch digestibility in protein-enriched cereal snack products. Extrusion cooking needs to be controlled if product quality is to be maintained. Extrusion cooking was carried out at barrel temperature of 110°C - 150°C, screw speed of 350 - 450 rpm, and feed moisture of 12% - 14% to investigate the effect of extrusion conditions on physical properties (expansion ratio and bulk density) of a rice, sorghum and soy flour blend. From response surface analysis, expansion ratio and bulk density were found to be significantly (P < 0.05) dependent on feed moisture and barrel temperature while the screw speed had a significant (P > 0.05) effect. Expansion ratio and bulk density ranged from 2.0 to 2.6 and 0.79 to 0.95 g/ml respectively. One hundred grams of the extruded product would supply 45% of the recommended daily allowance for protein in children aged up to 12 years. The mineral content in 100 g extrudates was found to be 52 mg calcium, 3.01 mg iron and 1.23 mg zinc. The retention of amino acids in the extruded products was 88% - 95% with lysine—a limiting amino acid in cereals having a loss of 9.1% after extrusion. Extrusion conditions can be optimized to produce ready-to-eat snack products with high expansion ratio, low bulk density and a good nutritional profile to meet the growing consumer needs for nutritious ready-to-eat snack products.

Physico-Chemical Characterization of Keitt Mango and Cavendish Banana Fruits Produced in Mozambique

Mangoes (Mangifera indica) and bananas (Musa acuminata) are climacteric fruits with a high potential for export due to their exotic aroma and sweet taste. This study aimed to characterize the physical and chemical parameters of Keitt mangoes and Cavendish bananas from different regions of Mozambique. The fruits were collected from Gaza, Manica and Nampula districts of south, central and north parts of Mozambique, respectively. The banana and mango samples were collected in Mid-August 2016 and January 2017, respectively. The fruits collected were at three different maturity stages (green, green-yellowish and yellow). The sample materials were characterised according to their centesimal composition, size, weight, firmness and colour. Analyses of soluble solids and ascorbic acid were, also, performed. The results revealed that the parameters were a good indicator of the maturity stage as well as for multivariate mango and banana applications and consumption. The parameters confirmed that mango fruits with low moisture (green with 83.62%), and fibers (0.44%), high ash (2.05%) crude lipids (0.29%), protein (0.85%) and carbohydrate (13.81%), high total soluble solids (24.60%), and high vitamin C content (14.83 mg/100g) were collected in Nampula with statistic differences (p < 0.05) between region of fruit production in Mozambique and stages of fruit maturity. However, banana fruits with low moisture (73.18%) and fibers (0.27%), high crude proteins (3.44%), ash (0.58%), and crude lipids content (4.92%), high total soluble solids (24.50%) and vitamin C content (2.40 mg/100g) were collected in Manica, where statistic differences (p < 0.05) were reported. This is the first time that Keitt mangoes and Cavendish bananas fruits have been characterized either in relation to the region of production in Mozambique or in relation to the various stages of maturity. This information can be exploited by various actors along the mango and banana value chain.

Antioxidant Effect of Roasted Barley (<i>Hordeum vulgare</i>L.) Grain Extract towards Oxidative Stress <i>in Vitro</i>and <i>in Vivo</i>

The antioxidant activity of extract from roasted barley grain was evaluated by various methods in vitro and in vivo. Results showed that the extract exhibited high antioxidant activities in vitro and in vivo, evidenced by its ability to chelate ferrous ions, scavenge hydroxyl and superoxide radicals, and prevent lipid peroxidation of liver homogenate. The extract significantly increased the total antioxidant capability (T-AOC) in aged mice (P < 0.05). The activities of antioxidant enzymes superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) increased while levels of malondialodehyde (MDA) and manoamine oxidase (MAO) decreased in both the liver and brain of aged mice treated with the extract compared to the control (untreated mice). The results demonstrate potential antioxidant activities and antiaging effect of roasted barley grain. This provides scientific support for the use of roasted barley grain as an antioxidant against oxidative stress.

Optimization of Hot Water Temperature Dipping and Calcium Chloride Treatment to the Selected Physico-Chemical Parameters of Keitt Mango and Cavendish Banana Fruits

Mango (Mangifera indica L.) and banana (Musa acuminata) are the most popular fruits in the world and widely cultivated crops in the tropical and subtropical zones. Keitt mangoes and Cavendish bananas are the largest cultivar of these fruits found in the Mozambique market. They are only available for a short period each year mostly during the late summer and early falls. Due to mango and banana fruits high water activity and respiration rate, are perishable foods and require conservation methods for preservation and availability. The aim of this study was to optimize the hot water-calcium chloride concentration treatment regime for improved postharvest handling of mangoes and bananas. The fruits collected were of uniform size, and at greenyellowish maturity stage based on length, diameter, colour and firmness. The process was optimized by experimental central composite design using hot water temperature (50°C - 60°C) and calcium chloride concentration (2% - 4%) with the aid of desirability function. The samples were analyzed for the centesimal composition, firmness, colour, °Brix, Aw, pH, titratable acidity and vitamin C. The results showed that hot water temperature and calcium chloride concentration were influent on the Keitt mangoes b* colour attribute, pH and titratable acidity as well as the Cavendish bananas firmness, ash and vitamin C content. The optimal conditions of the process were stabilized with the desirable function and, coincidentally for both crops, obtained at 55°C of hot water temperature dipping and 3% of calcium chloride concentration. The simulated data were similar to the experimental ones. This is the first time that calcium chloride-hot water treatment is being reported as a means of extending the shelf-life of mangoes and bananas.