Watermelon Rind Research Articles

Microwave-assisted aqueous two-phase extraction of l-Citrulline from watermelon rind: optimization, antioxidant potential, and microstructural insight

Microwave-assisted aqueous two-phase extraction of l-Citrulline from watermelon rind: optimization, antioxidant potential, and microstructural insight

Evaluation of Antidiabetic Effects of Watermelon Rind Extract: Integrative Computational Simulations and In Vitro Studies

Evaluation of Antidiabetic Effects of Watermelon Rind Extract: Integrative Computational Simulations and In Vitro Studies

Quality attributes and antioxidant activity of stirred yoghurt fortified with some nano-fruit waste powders

Agro-industrial wastes have emerged as a significant source of bioactive compounds. Therefore, this study was conducted to evaluate the feasibility of using nano-powders of some fruit wastes, namely; apricot (Prunus sp.) and peach (Prunus persica L. Batsch) kernels, watermelon (Citrullus lanatus) rind and banana (Musa spp.) peel as functional ingredients (0.5%) in stirred yoghurt, as well as their effect on the antioxidant activity, quality characteristics, viability of yoghurt starter culture and sensory attributes. Results revealed that the fortification process significantly (P < 0.05) elevated the total solids, fat, protein and ash contents, especially with apricot and peach kernels (AK and PK), which distinctly increased fat by average values of 3.46 and 3.40%, and protein by 3.70 and 3.68% during storage compared to control (3.12 and 3.57%), respectively. The addition of watermelon rind (WMR) increased the titratable acidity (0.97%) and viscosity (463.59 cP) with a significant reduction of syneresis (16.38%), increased the total viable count of starter culture, acetaldehyde and diacetyl contents (167.10 and 18.82 mg/100 g) in yoghurt, followed by banana peel (BP). Stirred yoghurt fortified with BP nano-powder had the highest total phenolic content (20.96 mg gallic acid/g) and DPPH scavenging activity (31.93%) as average values during storage compared to the other nano-fruit wastes. Sensory attributes of stirred yoghurt were improved with the addition of WMR and BP during storage periods, compared to those fortified with AK and PK. All the nano-powders of the studied fruit wastes constitute excellent raw materials for the development of novel functional stirred yoghurt.

Formulasi dan Evaluasi Ekstrak Aseton Kulit Putih Semangka Merah Non Biji (Citrullus Vulgaris S) dengan Niacinamide sebagai Gel Pelembab Kulit dengan Uji Kelembapan

This research was carried out with the aim of identifying the content of phytochemical compounds of alkaloids, flavonoids, tannins and saponins in the acetone extract of seedless red watermelon rind (Citrullus vulgaris), knowing the results of evaluating the physical properties of the acetone extract gel of seedless red watermelon rind (Citrullus vulgaris) with niacinamide against various concentrations of moisturizing gel preparations, and comparing the best moisture test concentration on acetone extract gel preparations of seedless red watermelon rind (Citrullus vulgaris) in providing optimal results. This research is a laboratory study of the experimental formulation of acetone extract of seedless red watermelon rind (Citrullus vulgaris) to determine the formulation and concentration of the best extract produced. The research results showed that acetone extract from the white skin of red seedless watermelon (Citrullus vulgaris) contained phytochemical compounds alkaloids, flavonoids, and polyphenol as well as lycopene in the white skin of red seedless watermelon (Citrullus vulgaris). The results of the evaluation of the physical properties of the acetone extract gel of seedless red watermelon rind (Citrullus vulgaris) in the negative control, 2.5% concentration, 5% concentration, and 7.5% concentration met the test requirements but did not meet the spreadability test requirements. And the best concentration of water content test in the acetone extract gel preparation of seedless red watermelon rind (Citrullus vulgaris) in providing optimal results is found in the gel preparation with a concentration of 7.5%.

Comparative Analysis of Pretreatment Methods for Fruit Waste Valorization in Euglena gracilis Cultivation: Impacts on Biomass, β-1,3-Glucan Production, and Photosynthetic Efficiency.

This study explored the sustainable valorization of fruit waste extracts from sugarcane bagasse (SB), banana peel (BP), and watermelon rind (WR) for Euglena gracilis biomass and β-1,3-glucan production. The extracts were prepared using water extraction (WE), high-temperature and pressure treatment (HTP), and dilute sulfuric acid treatment (DSA). The DSA-treated extracts consistently yielded the best results. E. gracilis cultured in SB-DSA showed the highest cell density with a 2.08-fold increase compared to the commercial HUT medium, followed by BP-DSA (1.35-fold) and WR-DSA (1.70-fold). Photosynthetic pigment production increased significantly, with chlorophyll a yield being highest in SB-DSA (1.90-fold increase). The chlorophyll a/b ratio and total carotenoid content also improved, indicating enhanced light-harvesting capacity and photoprotection. Photosynthetic efficiency, measured by chlorophyll fluorescence, notably improved. The maximum quantum yield of PSII (Fv/Fm) increased by up to 25.88% in SB-DSA, suggesting reduced stress and improved overall photosynthetic health. The potential photochemical efficiency (Fv/F0) showed even greater improvements: up to 40.53% in SB-DSA. Cell morphology analysis revealed larger cell aspect ratios, implying a more active cellular physiological state. β-1,3-glucan yield also increased by 23.99%, 12.92%, and 23.38% in SB-DSA, BP-DSA, and WR-DSA, respectively. This study demonstrates the potential of pretreated fruit waste as a cost-effective and sustainable medium for E. gracilis cultivation, offering the dual benefits of waste valorization and high-value compound production. These findings contribute to the development of more efficient biorefinery processes and align with the circular economy principles in food biotechnology.

Utilization of Watermelon Rind Puree as an Enhancer of Chips

This study was conducted to improve or develop food products and processing technologies specifically that will help in value-adding, creating new marketable forms that out from the watermelon rind that is usually thrown away or discarded. The study used experimental research using a completely randomized design with four treatments replicated thrice. Different measurements of watermelon rind puree were used to represent the treatments of the study. The products were evaluated by 50 respondents composed of ten (10) trained faculty on sensory evaluation of products; 35 student evaluators who know food preparation and evaluation of products and five (5) selected bakery owners from the Municipality of Sta. Maria Ilocos Sur. Results showed that T3 (400ml of watermelon rind puree) was best in all sensory evaluations and had the highest return on investment. Analysis of variance manifests that there is a significant difference between treatments. Based on the study, the watermelon cookies are considered healthy, acceptable, and nutritious. It contained ash of 1.12g, moisture content 12.96g, crude fat 11.0g, and 10.37g per 100 g of crude protein per 100 grams of the product. The technology should be subjected to further testing on shelf-life tests and physio-chemical tests. This study also recommends the use of watermelon rind as an enhancer in making pastry products like chips, marmalade, jams/jellies and other products.

The efficacy of prebiotic supplementation in mitigating heat stress and improving the survival of antibiotic-free broilers’ production in hot climates

BackgroundBangladesh is a hot tropical country, and various antibiotics have been included in broiler feed for many years to manage, prevent, and treat illnesses and improve production performance, like many other developing countries. This study mainly evaluates the efficacy of prebiotic supplementation in mitigating heat stress and improving the survival of antibiotic-free broiler production in hot climates.Materials and methodsA cocktail of banana peel, papaya peel, and watermelon rind was used as a prebiotic. A total of 350 one-day-old chicks (Ross-308) were allotted into five treatment groups each with 7 replicates: T1 (prebiotics, 15 ml/L), T2 (commercial probiotics Lactolase P, 1 g/L), T3 (synbiotics, 7.5 ml/L prebiotics + 0.5 g/L probiotics), T4 (freshwater), and T5 (antibiotics, 1 g/L). Besides other treatments, the aqueous extracts of banana peels, papaya peels, and watermelon rinds were prepared as prebiotics, and these were provided to the experimental birds through drinking water from 5 to 32 days of age.ResultsThe findings revealed nonsignificant (P > 0.05) variations in water intake, feed intake, feed conversion ratio (FCR), dressing weight, dressing percentage, heart and gizzard weights, and thigh meat yield. Significant (p < 0.05) differences were observed in body weight, body weight gain, and breast meat yield. It was observed that birds consumed five times more water than feed when the environmental temperature was above 38 °C. Significant (p < 0.05) differences in the survival rates of birds were observed among treatment groups. The highest rate of survival was obtained in T1 (100%), followed by T2 (93.3%), and T3 (90%), and the lowest percentage was recorded in T4 (66.6%) and T5 (73.3%).ConclusionPrepared prebiotics could mitigate heat stress, promote growth rate under hot climates, and be used as substitutes for antibiotics to safely produce broilers in hot climates.

Reproductive tract morphometry of Hyla rabbits fed diet containing graded levels of watermelon rind and wheat offal as absorbent

The evaluation of breeding and fertility potential of animals demands understanding of basic morphometric characteristics of their reproductive organs which, among other factors, may be affected by nutrition. This study was conducted to assess the effects of feeding graded levels of watermelon rind and wheat offal as absorbent on morphometric characteristics of the reproductive organs of Hyla rabbits. Forty-five Hyla rabbits of both sexes (15 bucks and 30 does) with nine animals per treatment (3 bucks and 6 does in each treatment) in a completely randomized design were randomly assigned to the dietary treatment containing 0 %, 10 %, 20 %, 30 %, and 40 % of watermelon rind and wheat offal. The data collected included weight and length of the reproductive tract of the rabbits. The morphometric characteristics of reproductive tract of the rabbits were not significantly affected by the dietary treatment, however, there were significant effect (p &gt; 0.05) of the dietary treatment on the weight of the left oviduct, paired oviduct, and the paired ovary of the rabbits. The experimental diets significantly affected (p &lt; 0.05) penis length and width, the right spermatic cord and the length of the right scrotal. The diets had no significant effect (p&lt;0.05) on the weight of reproductive tracts of buck except on the paired spermatic cord. The experimental diets can be a good alternative for the highly competitive and costly grains in the diet of Hyla rabbits without any adverse effect on the growth of reproductive organs and consequently on the fertility and other activities related to reproduction of Hyla rabbits. Keywords: morphology, rabbits, reproduction, watermelon rind, wheat offal

Discovering bioactive phytoconstituents from Citrullus lanatus for antimicrobial and antioxidants therapeutic applications

In recent decades, significant interest in natural bioactive compounds has led many researchers to study plants as primary natural sources of bioactive compounds, mainly when considering a few biological properties, including antioxidant, antimicrobial, and anti-inflammatory activities, and as nutritional supplements with health benefits. We designed this study to explore the phytochemicals profiling of Citrallus lanatus and evaluate their in vitro bioactive properties. The methanol extraction of the watermelon's stem, rind, and leaf parts through Soxhlet extraction was analyzed using Gas Chromatography-Mass Spectrometry. The GC-MS profiling of Citrullus lanatus examines the presence of numerous bioactive phytoconstituents with potential biological activities such as antioxidant, anti-inflammatory, antimicrobial, anticancer, and other properties. We have evidenced that the stem, rind, and leaf extracts with significant antioxidant and antimicrobial activities against clinically relevant pathogens like Salmonella typhi, Pseudomonas aeruginosa, Bacillus subtilis, and Staphylococcus aureus. Overall, our study sheds light on exploring novel bioactive phytoconstituents from Citrullus lanatus and explore, harness these compounds' therapeutic potential for human health.

Enhancing Drought Tolerance in Barley through the Application of Watermelon Rind Hydrogels: A Novel Approach to Sustainable Agriculture

Enhancing Drought Tolerance in Barley through the Application of Watermelon Rind Hydrogels: A Novel Approach to Sustainable Agriculture

Fruit waste-derived carbon dots with rhodamine B for the ratiometric detection of Fe3+ and Cu2.

A green and eco-friendly solvothermal approach is proposed for the synthesis of carbon quantum dots (CQDs) from watermelon rind. The as-prepared CQDs exhibited superior teal fluorescence in aqueous solutions, with a quantum yield of 13.9%. The CQDs and rhodamine B (RhB) were demonstrated to selectively react with Fe3+ and Cu2+, leading to a fluorescence (FL) quenching effect, which was successfully used for constructing "double-response-off" type ratiometric FL probes. A comparative study was conducted to assess the sensitivity and accuracy of ratiometric fluorescent probes, specifically those based on CQDs alone and in combination with RhB, for the selective detection of Fe3+ and Cu2+. By plotting the ratio of the differential fluorescence (ΔF) signals of CQDs to that of RhB against the practical application analyte concentration, the detection limits for Fe3+ (1.75 μM) and Cu2+ (0.43 μM) were markedly improved. The quenching mechanism was further explored, and the detection of Fe3+ and Cu2+ in surface water was demonstrated, showcasing the potential of efficient and effective nanosensors based on a static quenching effect. Futhermore, the addition of ascorbic acid can restore the fluorescence quenched by Fe3+. Therefore, in the presence of copper and iron, the ratiometric probe can demonstrate the ability to identify two different metals.

Standardization of a recipe for the preparation of Tutti Frutti from watermelon rind (Citrullus lanatus)

Standardization of a recipe for the preparation of Tutti Frutti from watermelon rind (Citrullus lanatus)

Development and evaluation of probiotic jam from watermelon rind with microencapsulated Lactobacillus rhamnosus and Lactobacillus casei

Watermelons are generally consumed fresh, but their rind is disposed of as waste. In the present study, jam variants of watermelon (cv. Sugar Baby) were prepared with rind and pulp. Jam variants were inoculated with chitosan-coated calcium alginate beads with prebiotic inulin microencapsulating probiotic Lactobacillus rhamnosus (ATCC 7469) and Lactobacillus casei (ATCC 393). Micro-encapsulated probiotics survived better in simulated intestinal juices than in gastric juices. During ninety days of storage, jam variants’ physicochemical, sensory and microbial properties were assessed. Micro-encapsulated probiotics had a non-significant effect on the physico-chemical characteristics of watermelon jam variants during storage. In the sensory analysis of watermelon jam variants, jam having 50% endocarp and 50% rind was most accepted. A probiotic count of 107 colony forming unit per gram was observed in the rind jam variant after ninety days of storage, and no coliform count was observed. Present work implies that a novel synbiotic (probiotic with prebiotic) jam could be prepared using watermelon rind.

Microbiological and Chemical Characteristics of Yoghurt Incorporated with Watermelon Rind Powder

Watermelon rind accounts for approximately one-third of the overall fruit mass. It is usually discarded due to its low commercial value. However, it is reported to contain valuable nutrients and is an effective source of pectin that can act as a potential prebiotic. This study aimed to study the effects of watermelon rind powder (WRP) on the growth of probiotic bacteria in yoghurt and its chemical characteristics. Watermelon rind was dried by using a dehydrator and ground into powder form before being incorporated into fresh yoghurt at 2% and 4% w/v. A sample with 0% w/v WRP was prepared as control. The effect of WRP on the growth of probiotic bacteria was determined by MRS plate count. Chemical analyses including titratable acidity, pH and Brix were conducted during the fermentation process. The results showed that the increase in WRP percentage resulted in a significant increase in bacterial growth with 7.20 ± 0.22 log CFU/mL for the control sample as compared to 8.42 ± 0.23 log CFU/mL for sample with 4% WRP after 30 hr of incubation. The fermentation time was also improved with the presence of WRP with a 0.22 h-1 increase in growth rate observed for the sample with 4% WRP as compared to the control sample. Furthermore, samples containing 4% WRP showed the highest increment in titratable acidity (12.47) and the highest percentage in Brix value reduction (51.04%) during the fermentation period as compared to the control sample. Biochemical analysis showed negative values for oxidase and catalase test while positive values were obtained for gram-staining indicating the presence of Lactic acid bacteria from the gram-positive group. This study demonstrates the high potential of WRP in promoting bacterial growth for yoghurt production which is beneficial to the food industry other than promoting the ongoing effort of food waste reduction.

Transforming watermelon (Citrullus lanatus) rind into durable superabsorbent hydrogels for enhanced soil water retention properties and adsorbs dye in water

Innovative superabsorbent hydrogels were synthesized from watermelon rind (WR), an abundant agricultural waste. The process involved free radical polymerization of acrylic acid (AA) and acrylamide (AAm) with WR particles activated by ammonium persulfate (APS), resulting in (AA-co-AAm)/WR hydrogels with high equilibrium swelling capacities of 749 ± 32 g/g. Notably, after eight cycles, the WR hydrogel maintained 94.88 % of its initial swelling capacity, significantly outperforming the (AA-co-AAm) hydrogel without WR (13.80 % retention). This durability, combined with excellent water retention across various soil textures and high adsorption capacity for methylene blue (MB), underscores the WR hydrogel as a superior soil moisture conservation agent. This study marks a significant advance in recycling organic waste and enhancing water management in agricultural soils, demonstrating the potential for sustainable hydrogel development.

Molecular Markers and Marker-Assisted Selection Provide Genetic Insights for Identifying Key Quantitative Trait Locus for Watermelon Rind Thickness.

Rind thickness (RT) is an important agronomic trait in watermelon [Citrullus lanatus (Thunb.) Mansf.] and affects watermelon storability. However, genetic studies on this trait, as well as gene regulation studies, are scarce and of limited production significance. We constructed a temporary F2 generation using the highly differentiated thick-rind watermelon 'XiaoXiGua-4' and the thin-rind watermelon 'DuanMan' as parents and localized the Cla97C02G044120 gene, which controls the thickness of watermelon rind, to the intervals of chromosome 2, CL2-32303995 and CL2-32316840, through 2 years of genetic analysis. No exonic mutations were found in this gene, but two promoter mutations resulted in changes in the promoter progenitor. Fluorescence quantitative PCR analysis revealed highly significant differences in expression at 1 d and 28 d, and the expression was significantly lower in thick-skinned watermelon varieties. Marker-assisted selection (MAS) for this trait was performed using the Caps marker CL2-32303995 and the InDel marker CL2-32316840, which not only verified the stability of the localization interval but also distinguished thick rind from thin rind. These results can be used for germplasm resource screening and have strong breeding significance.

Optimizing the microwave-assisted extraction and ultrasonic-assisted processes to acquire flavonoid and phenolic compounds from watermelon rinds using natural deep eutectic solvents

ABSTRACTS This study extracted flavonoids and phenolics from watermelon fruit by microwave-assisted extraction (MAE) and ultrasound-assisted extraction (UAE) combined with a natural deep eutectic solvent (NADES). The effectiveness of NADES combined with UAE and MAE was evaluated for extracting these compounds from watermelon rinds. The study chose a 2:1 molar ratio of hydrogen bond donors (HBDs) to hydrogen bond acceptors (HBAs). Among the tested combinations, 1,2-propanediol-lactic acid showed the highest solubility for flavonoids and phenolics within the extraction system. Experiments with a single factor were used to examine the effects of different parameters on total phenolic content (TPC) and total flavonoid content (TFC). The Box-Behnken design (BBD) model optimized the NADES-based UAE and MAE processes based on TPC and TFC responses. The results of the experiment and the predicted values from the BBD agreed well. Optimal conditions for recovering phenolics and flavonoids from watermelon rinds with NADES-based UAE were determined as 1/60 g/ml for SLR, 300 W, 20% water content, and 15 min, while NADES-based MAE: 1/50 g/ml for SLR, 400 W, and 3 min. This study presents an efficient approach for extracting biologically active compounds from watermelon.

Enhanced osmotic dehydration of watermelon rind using honey-sucrose solutions: A study on pre-treatment efficacy and mass transfer kinetics.

This study investigates the osmotic dehydration process of watermelon rind using a solution composed of honey and sucrose. The impact of the ratio of rind-to-solution and temperature on the process is illustrated. Pre-treatments such as blanching, microwaves, and ultrasonication were utilized. Ultrasonication reduces the time needed for osmosis in a sample, resulting in increased fluid loss and solute uptake; therefore, it was selected as the method to investigate the kinetics and modelling of mass transfer. The effective diffusivities for water loss (ranging from 3.02 × 10-5 to 4.21 × 10-4 m2 s-1) and solid gain (ranging from 1.94 × 10-6 to 3.21 × 10-6 m2 s-1) were shown to increase with process variables such as temperature and the rind-to-solution ratio. The activation energy decreased as the process temperature increased, ranging from 3.723 to 0.928 kJ mol-1 for water loss and from 1.733 to 0.903 kJ mol-1 for solid gain, respectively. The sample treated with microwaves exhibited the maximum dehydration coefficient, rendering it appropriate for producing dehydrated products. Five empirical models were utilized, with the power law model (R 2 = 0.983) and the Magee model (R 2 = 0.950) being the most suitable for water loss data and solid gain, respectively.

Developing and implementing a facile colorimetric method for detecting salicylic acid in raw milk via biogenic plasmonic nanostructures

Consumption of adulterated milk poses serious health hazards to people of all age groups. Salicylic acid, being a common milk adulterant is added at a rate of 0.04–0.05 % to prolong its shelf life yielding severe health complications. Despite a global regulatory ban, deliberate use of this adulterant remains widespread. This study addresses the problem by developing an effective sensing scheme using biologically synthesized silver nanoparticles from watermelon rind extract to detect salicylic acid in raw milk. Characterizations were performed through UV–Vis spectrophotometry, X-ray diffractometer, Field Emission Scanning Electron Microscopy, Zeta Sizer, Transmission Electron Microscopy, and Fourier Transform Infrared Spectroscopy. The colorimetric sensing method indicates the presence of salicylic acid by a change in colour from bright yellow to brown/black. The limit of detection is found to be 0.55 ppm, where the dynamic range of detection was between 0.1 ppm to 15 ppm, with a recovery rate between 85-106%.

Physicochemical and sensory quality of high antioxidant fruit leather of red dragon fruit and watermelon rind enriched with seaweed

Fruit, as a source of antioxidants and phenolic compounds, is perishable. It also has an underutilized component. Fruit leather has a long shelf life in the form of thin sheets with a distinctive texture. This study aimed to investigate the effect of seaweed (Eucheuma cottonii) addition on the physicochemical and sensory quality of fruit leather made from the combination of red dragon fruit and watermelon rind. The physicochemical quality was characterized by measuring the critical quality parameters of fruit leathers, including proximate analysis, water activity, total phenol, antioxidant activity, texture, and organoleptic analysis. The statistical analysis of phenolic compound activity, antioxidant activity, vitamin C, moisture content, carbohydrates, and water activity (aw) was conducted using a one-way ANOVA test, while the analysis of ash content, protein, fat, tensile strength, elongation, and organoleptic properties was performed using the Kruskal–Wallis test. Increasing seaweed concentration significantly increased moisture, ash, protein, vitamin C, total phenol, water activity, and elongation but decreased fat content. Furthermore, the increase in seaweed concentration reduced liking toward taste and color significantly but increased texture liking. The best product was the F2 product with 10% seaweed. F2 has the following attributes: 11.07% of moisture content, 2.34% of ash, 1.53% of protein, 0.19% of fat, 84.86% of carbohydrate, 8.17 mg/100 g of vitamin C, 0.41 of water activity, 0.54 N/m2 of tensile strength, 22.22% of elongation, 107.39 ppm of IC50, 1.66 mg/GAE g of total phenolics.