Optimization of the pulp ratio of Ananas comosus, Citrullus lanatus and Psidium guajava and fermentation time in the production of a "fruit brandy".

Brandy, produced by the distillation of wine, is highly consumed in Cameroon, most of which is imported, whereas this region harnesses a vast diversity of fruits, which could be exploited in producing wines and spirits. These fruits have interesting health virtues and are prone to rapid postharvest losses. This study is aimed at producing brandy from a combination of pineapple (Ananas comosus), watermelon (Citrullus lanatus) and guava (Psidium guajava), with an objective to optimize the ratio of fruit pulps and fermentation time in order to produce wine, then brandy of acceptable taste and flavor. A D-optimal 3-component, 1-factor experimental design was used to obtain the best wine formulation to be distilled. The factors retained were: the volumes of Pineapple (A), watermelon (B) and guava (C) and the fermentation time (D) was considered as a process factor. Based on the experimental design using Design Expert 11 software, 24 wine samples were formulated. After statistical analyses, the pH, alcohol content and viscosity were considered for mathematical modeling due to their significant impacts during fermentation (pH and viscosity) and distillation (alcohol content). Optimization for wine production gave a fruit formulation of 69, 19 and 12% of pineapple, watermelon and guava respectively, with a fermentation time of 11 days. Distillation of this wine gave an ethanol output of 72%, from which two distinct Brandy was obtained: one (E1) in which dilution was done with clarified wine, and the second (E2) with distilled water and a roasted bark of Cupressus sempervirens (cypress) added to it. After six weeks of aging at ambient temperature, physicochemical characteristics showed a vitamin C content of 100 and 80 mg/L, polyphenols content of 22.77 and 42.77 mqGAE/100 g, and a titratable acidity of 1.42 and 0.45 meq.g of tartaric acid respectively for E1 and E2. After sensory analysis, brandy sample E1 was preferred.

Inclusion of partly purified protease from Abrus precatorius Linn in Ca-alginate gel beads.

Abrus precatorius is an edible endemic plant in Cameroon. In the northern regions of Cameroon, the leaves of this plant are used as traditional medications, for the liquefaction of wort obtained after mashing of sorghum or millets for processing the local fermented beer called bili-bili, and to sweeten gruels made from red millet. Abrus precatorius has also being explored as a potential source of proteolytic enzymes. In this work, a partially purified protease from the leaves and stems of the plant was immobilized in a calcium alginate gel beads and the protease activity (PA), investigated using a central composite design plan under the conditions: alginate content (1-5%) (w/v), enzyme/alginate ratio (10-30%) (v/v), and CaCl2 concentration (100-400 Mmol/L). Results showed that the optimum activity was obtained for an alginate content of 1% (p/v), an enzyme/alginate ratio of 10% (v/v) and a CaCl2 concentration of 400 mmol/L. At the optimum, kinetic parameters of the immobilized enzyme (KM: 6.83 mg mL-1; Vmax: 46.95 g.L-1. min-1) were comparable to those of free enzyme (KM: 1.26 mg mL-1; Vmax: 153.85 g.L-1. min-1). The beads have been preserved at room temperature and reused for four days before loosing 88% of its activity. This indicates that the protease activity of the leaves and stems of A. precatorius can be immobilized in calcium alginate beads and preserve four days at ambient temperature.

Optimization of extraction conditions of phenolic compounds from Cymbopogon citratus and evaluation of phenolics and aroma profiles of extract.

Decoction extraction procedure was implemented to regain phenolic compounds from C. citratus leaves. The extraction variables, solid/liquid ratio (2-5 g/100 mL), temperature (85-95 °C), and time (5-10 min) were assessed by central composite design for process optimization. Antioxidant activity (DPPH) and total polyphenol content (TPC) were monitored as responses. The TPC and DPPH were 71.98 ± 0.33 mg GAE/100 mL extract and 80.63 ± 0.49 mg TE/100mL extract respectively under optimal conditions (solid/liquid ratio = 5, temperature = 93.8 °C and time 11.3 min). The evaluation of phenolic compounds and volatile compounds of C. citratus extract at conditions for optimum extraction revealed that caffeic (20.81 ± 0.003 mg/100mL) and syringic acids (18.63 ± 7.390 mg/100mL) were the main phenolic compounds while citral and geraniol were the primary volatile compounds. The results achieved herein suits the potential use of C. citratus extract as natural source of antioxidant and aroma compounds that can be employed in different industrial sectors. PRACTICAL APPLICATION: Lemongrass obtained at the optimal extraction conditions is a good source of antioxidants and the extract has organic acids and a lemon scent due to the presence of citral. This extract can thereby be incorporated in the production of beverages which can help aromatize the beverage and also contribute in the addition of the antioxidant property of the beverage. It is also rich in organic acids, the main being propionic acid, which is known to have antimicrobial activity primarily against bacteria and mold. The lemongrass extract can therefore, extend the shelf life of the beverage they are incorporated in and also the citral present in lemongrass has antimicrobial properties.