Optimization and Preliminary Physicochemical Characterization of Pectin Extraction from Watermelon Rind (Citrullus lanatus) with Citric Acid

Watermelon rind was used for the pectin extraction with citric acid as the extractant solvent. The effects of pH (2.0-3.0), extraction time (45-75 min), and liquid-solid ratio (10 : 1 to 40 : 1 mL/g) on the pectin yield, degree of esterification, methoxyl content, and anhydrouronic acid content were investigated using Box-Behnken surface response experimental design. The pH was the most significant variable for the pectin yield and properties. The responses optimized separately showed different optimal conditions for each one of the variables studied in this work. Therefore, the desirability function was used to determine the sole theoretical optimum for the highest pectin yield and highest anhydrouronic acid content, which was found to be pH of 2.0, extraction time of 62.31 min, and liquid-solid ratio of 35.07 mL/g. Under this optimal condition, the pectin yield, degree of esterification, methoxyl content, and anhydrouronic acid content were 24.30%, 73.30%, 10.45%, and 81.33%, respectively. At optimal conditions, watermelon rind pectin can be classified as high methoxyl and rapid-set pectin with high quality and high purity. Practical Applications. This study evaluated the pectin extraction from watermelon rind and carried out an optimization of multiple responses as a function of pH, time, and liquid-solid ratio to obtain the best preliminary quality parameters (pectin yield and anhydrouronic acid content). The results revealed that watermelon rind waste can be an inexpensive source to obtain good pectin quality and high purity. According to the chemical characterization and physicochemical properties studied, the extracted pectin from watermelon rind would have a high potential to be used in food industry.

Effects of addition of Sodium Benzoate of the Physicochemical Characteristic of Watermelon rind (Citrullus lanatus)

Watermelon rind is a food product that utilize wasted albedo waste. Generally, jam is gel or semi-dense so it has short shelf life. To make the jam more imperishable in storage, preservatives can be added in manufactured progress, one of the preservatives that can be used is sodium benzoate. This research aims to determine the effects of the addition of sodium benzoate on the physicochemical characteristics of watermelon rind jam. The results reveals that the formula of watermelon rind jam with the addition of sodium benzoate has physicochemical content that not much different apart from the one that isn’t added by sodium benzoate. The characteristics that were significantly different were only in viscosity, the jam with the addition of sodium benzoate (6400 cP) was greater than the jam without the addition of sodium benzoate (2900 cP). The selected formula will be tested by organoleptic (hedonic quality) with texture, taste, and aroma attributes with the results that the jam formula was well received by 30 panelists. The quality of watermelon rind jam is identified by color aspect with average score of 5.10 with good category that has brownish yellow color, by texture with average score of 5.10 with good category that has soft and fibrous textured, and by the taste with average score of 5,20 with good category that has sweet acidity taste. Keywords: Watermelon rinds, sensorics analysis

PENGARUH JUS KULIT BUAH SEMANGKA (Citrullus lanatus) TERHADAP STATUS HIDRASI ATLET DI UKM SEPAK BOLA

Background: Football as a high-intensity sport that causes fluid loss in the body often makes athletes dehydrated which results in decreased athlete performance. Provision of adequate and appropriate drinks can prevent dehydration. Watermelon rind contains high potassium which can restore lost body fluids.Objectives: Conducted a study to determine the correlation of giving watermelon rind juice to the hydration status of athletes in the Student Football Activity Unit.Methods: The study was conducted with a quasi-experimental design with a pre-posttest without control group design. A sample of 18 soccer athletes was taken using a purposive sampling technique. Subjects were given 300 ml of watermelon rind juice for 7 days. Hydration status was obtained based on the results of urine specific gravity examination. Measurement of hydration status wasconductedbefore and after the intervention period. The research instruments were urine samples analyzed in the laboratory, SOPs for making watermelon rind juice, observation sheets for giving juice, SOPs for measuring hydration status, and hydration status observation sheets. Data analysis using Wilcoxon test.Results: Specific gravity of pretest urine obtained a median of 1.025 g/dl (min-max 1.005-1.030 g/dl). Posttest urine specific gravity received a median of 1.025 g/dl (min-max 1.010-1.031 g/dl). There was an average decrease in urine specific gravity of 0.0019 g/dl at the posttest. The results of the pretest and posttest bivariate analysis obtained a p-value of 0.391.Conclusion: There is no significant effect of watermelon rind juice on the hydration status of athletes in the Student Football Activity Unit. There is a decrease in the average specific gravity of urine after being given watermelon rind juice

Adsorption of Zn2+ from Synthetic Wastewater Using Dried Watermelon Rind (D-WMR): An Overview of Nonlinear and Linear Regression and Error Analysis

Sustainable wastewater treatment is one of the biggest issues of the 21st century. Metals such as Zn2+ have been released into the environment due to rapid industrial development. In this study, dried watermelon rind (D-WMR) is used as a low-cost adsorption material to assess natural adsorbents’ ability to remove Zn2+ from synthetic wastewater. D-WMR was characterized using scanning electron microscope (SEM) and X-ray fluorescence (XRF). According to the results of the analysis, the D-WMR has two colours, white and black, and a significant concentration of mesoporous silica (83.70%). Moreover, after three hours of contact time in a synthetic solution with 400 mg/L Zn2+ concentration at pH 8 and 30 to 40 °C, the highest adsorption capacity of Zn2+ onto 1.5 g D-WMR adsorbent dose with 150 μm particle size was 25 mg/g. The experimental equilibrium data of Zn2+ onto D-WMR was utilized to compare nonlinear and linear isotherm and kinetics models for parameter determination. The best models for fitting equilibrium data were nonlinear Langmuir and pseudo-second models with lower error functions. Consequently, the potential use of D-WMR as a natural adsorbent for Zn2+ removal was highlighted, and error analysis indicated that nonlinear models best explain the adsorption data.