Fresh Watermelon Juice Research Articles

Low-frequency ultrasonic treatment: A potential strategy to improve the flavor of fresh watermelon juice.

A molecular sensory science approach was used to explore the effects of ultrasonic treatment on aroma compounds of watermelon juice. Watermelon juice was submitted to ultrasonic power at 325W for 20min. Ultrasonic treatment reduced odor related to cucumber and green descriptors, whilst significantly improved odors related to sweet, floral, and fruity descriptors, thus contributing to the overall flavor of watermelon juice. Compared with untreated watermelon juice, the amount and concentration of volatile compounds in ultrasonicated watermelon juice increased by 82.50% and 111.84%, respectively. Notably, 22 alkene compounds were newly formed in ultrasonicated watermelon juice, which contributed to sweet and fruity aroma of watermelon juice. The findings of the present study suggest that ultrasonic treatment may be a potential method to improve the overall flavor of watermelon juice.

Effect of Storage Temperatures on Physico-Chemicals, Phytochemicals and Antioxidant Properties of Watermelon Juice (Citrullus lanatus).

Watermelon (Citrullus lanatus) consists of high moisture content and is favoured for its juice products. The popular fruit has a tempting taste, sweet aroma and attractive flesh colour. It is enriched with phytochemicals and antioxidant properties that are beneficial to human health. Due to convenience, the majority of individuals are likely to consume watermelon juice. However, little is known about the fruit juice storage and temperatures that may affect its beneficial properties. This study investigated the effect of storage temperature at room temperature, refrigerator cold, refrigerator freeze and freeze-dried, and analyzed the juice physico-chemicals (weight loss, pH, ash, moisture, total soluble solid, browning and turbidity), phytochemicals (total phenolic, total flavonoid, lycopene and β-carotene) and antioxidant scavenging activities during 9 days of storage. The results showed that watermelon juice was affected by storage temperatures and conditions with significant changes in physico-chemical appearance and decrease in total phytochemical content, thus consequently affecting their antioxidant activities during 9 days of storage. Although fresh watermelon juice can be consumed for its high nutritional values, freeze-drying is the preferable technique to retain its benefits and to delay juice degradation.

Antilithiatic effect of watermellon (Citrullus lanatus) juice on Calcium Oxalate kidney stones

Background: Nephourolithiasis is a term refers to kidney stones formation, due to aggregation of minerals leading to the development of crystalluria in kidneys or any part of the urinary tract system. Many herbs were used to fragment and crush renal calculi. Habitually, it is noted that people who suffer from kidney problems are advised to eat large quantities of watermellon fruit then, the patient feels healing, without knowing the scientific reason for this improvement. Objectives The current study was designed to investigate the antilithiatic effects of Fresh Watermelon Juice (FWJ) on calcium oxalate kidney stones. Methods Direct exposure technique between FWJ and enucleate stons was used. The pH, and electrical conductivity (EC) of the exposure solution in addition to the chemical and morphological properties of the renal calculi before and after exposure using X-ray diffraction method (XRD) and scanning electron microscope (SEM) were investigated. Results: after 24 hours of submerging renal calculi with FWJ, the calculi appeared dissolved and fragmented with absence of solidity, rigidity and crystallization. The Ph Value and electrical conductivity (EC) of FWJ increased significantly after 24 hours of submerging the calculi increasing total soluble solids and ion concentrations in the solution. X-ray diffraction showed sharp peaks and intensity of of calcium oxalate calculi indicating a significant change in calculus compositionn, shape and crysallization within 48 hours of exposure FWJ.Scanning electron microscope images of treated and untreated renal calculi showed a significant difference in the shape of the crystals that have been transformed from their regular shape as bipyramids with tetragonal crystal point group symmetry to sculpted and un coordinated particles with the absence of a regular geometric shape of crystals with no clear crystallization patterns. Conclusion: Fresh watermellone juice appears to have a strong effect on the shape and composition and integrity of renal calculi which may aid its expulsion from the body.

Quality of Watermelon Juice Concentrated by Forward Osmosis and Conventional Processes

Watermelon (Citrullus lanatus) juice is known for its refreshing flavor, but its high perishability limits its availability throughout the year. Watermelon juice concentrate has extended shelf-life and lower transportation and storage costs, but the conventional thermal evaporation process for concentrating juice degrades the nutritional components and sensory quality of the product. Thus, in this work, a large-scale, non-thermal forward osmosis (FO) process was used to concentrate fresh watermelon juice up to 65°Brix. The FO concentrate was compared to thermal concentrate and fresh juices, and to commercially available refrigerated watermelon juices, in terms of lycopene and citrulline content, total soluble phenolics, antioxidant activity, and sensory properties. The FO concentrate had statistically similar (p < 0.05) levels of all the nutrients of interest except antioxidant activity, when compared to the thermal concentrate. The reconstituted FO concentrate maintained the same antioxidant activity as the raw source juice, which was 45% higher than that of the reconstituted thermal concentrate. Sensory results showed that reconstituted FO concentrate resulted in highly liked juice, and it outperformed the reconstituted thermal concentrate in the sensory hedonic rating. This work demonstrates the possibility to produce a high-quality watermelon juice concentrate by forward osmosis.

Screening of the volatile compounds in fresh and thermally treated watermelon juice via headspace-gas chromatography-ion mobility spectrometry and comprehensive two-dimensional gas chromatography-olfactory-mass spectrometry analysis

Previously, the aroma compounds in watermelon juice were analyzed by either GC-MS or GC-O. These methods could not extract and analyze the volatile compounds comprehensively. Compared to the previous studies, for accurately identifying the aroma profile, the volatile compounds in fresh watermelon juice (FW) and thermally treated watermelon juice (TW) were analyzed using HS-GC-IMS and GC × GC-O-MS. Twenty-three compounds were detected by HS-GC-IMS, among them, allyl methyl sulfide, acetoin, and pentanal were identified for the first time in TW. Through GC × GC-O-MS analysis, 130 and 140 compounds were detected in FW and TW, respectively, and 36 and 38 of these compounds were smelled. In this study, 2,6-dimethyl-5-heptenal was identified for the first time in FW as an odor-contributing compound. These two kinds of juices could be differentiated by heat-mapping. The concentrations of (E)-2-decenal, decanal, 2-hexenal, 2-pentylfuran, and 6-methyl-5-hepten-2-one increased greatly by Volcano plot, and they contributed to the off-flavor in TW. For aroma analysis of watermelon juice, HS-GC-IMS can rapidly analyze the samples with low detection limits without pretreatment, while GC × GC-O-MS can precisely identify the compounds with sniffing. The results of this study suggest that HS-GC-IMS and GC × GC-O-MS can analyze the aroma profile more comprehensively and discriminate FW and TW more efficiently.

Is overnight fresh juice drinkable? The shelf life prediction of non-industrial fresh watermelon juice based on the nutritional quality, microbial safety quality, and sensory quality.

ObjectiveThe aim of this study was to obtain the time range of non-industrial fresh watermelon juice (FWJ), which is widely used in the catering industry under different storage conditions, with safe-drinkable quality, and the drinking time range of fresh juice with good nutritional quality and sensory quality.MethodThe quality of non-industrial FWJ was audited by assessing the shelf life of non-industrial FWJ through microbial safety, nutritional, and sensory quality investigating during 24 h of storage at 4, 25, and 37°C.ResultsAccording to the microbial safety quality, the safe drinking time of FWJ was within 12, 4, and 4 h when stored at 4, 25, and 37°C, respectively. Based on the nutritional and sensory quality, FWJ was drinking with good quality within 2 h, and with just acceptable quality for no more than 4 h when stored at 4 or 25°C. Electronic nose and gas chromatography–mass spectrometry (GC–MS) could effectively distinguish and identify the changes in volatile components in FWJ under different storage conditions.ConclusionIt is a feasible method to predict the shelf life of non-industrial FWJ by this method, and hence to guarantee non-industrial FWJ being drinking with safety and health, and it might be used in many other fresh juice shelf life predictions.

The Effects of Fresh Watermelon Juice Consumption on Satiety, Postprandial Glucose, Insulin Response, and Topical Application on Skin Health in Healthy Adults

Abstract Objectives Multiple studies have examined the effects of fresh watermelon, watermelon juice, or watermelon powder on satiety and skin health; however, few studies have addressed the effects of blenderized (flesh, rind, and seeds) watermelon juice. The objective of this study was to determine the effects of blenderized watermelon juice consumption on satiety, postprandial glucose, insulin response, and topical application on skin health in healthy adults. Methods In a crossover design, subjects (N = 20, 16 females, 4 males, age 22.8 ± 2.5 y, BMI 22.6 ± 2.80 kg/m2) consumed 8 fl oz of either blenderized watermelon juice or isocaloric sugar water. After an overnight fast, blood glucose and insulin levels were measured at baseline, and at 30 and 60 minutes after drink consumption. Measurements for satiety using a visual analogue scale and skin health using a moisture content test were conducted at baseline, right after, 15, 30, 45, and 60 minutes after consumption and topical application of the juices. Results Both blenderized watermelon and sugar water significantly increased satiety (P < 0.001) but there was no difference between the two trials. Postprandial glucose (P = 0.030) and insulin levels (P = 0.007) significantly increased after the consumption of sugar water compared to blenderized watermelon juice. Topical application of blenderized watermelon juice on the skin significantly increased skin moisture level (P = 0.012) compared to the sugar water application. Conclusions The consumption of blenderized watermelon promoted satiety, stabilized postprandial glucose and insulin levels, and improved skin health. These results suggest that blenderized watermelon juice may be beneficial for those who are overweight or obese and/or are at risk of developing diabetes. Further watermelon studies are warranted to examine long-term effects. Funding Sources National Watermelon Promotion Board (NWPB 19-20).

Microfluidic paper based membraneless biofuel cell to harvest energy from various beverages

The present work establishes the cost-effective and miniature microfluidic self-pumping paper based enzymatic biofuel cell (P-EBFC). The developed Y-shaped P-EBFC consists of buckeye composite multiwall carbon nanotube (MWCNT) buckypaper (BP) based bio-anode and bio-cathode that were immobilized with electro-biocatalytic enzymes glucose oxidase (GOx) and laccase, respectively. The electrocatalytic activity of enzymes on electrode surface is confirmed using cyclic voltammetry (CV) technique. Such immobilized bio-anode and bio-cathode show exquisite electrocatalytic activity towards glucose and O2, respectively. Most appealingly, P-EBFC can directly harvest energy from widely available beverages containing glucose such as Mountain Dew, Pepsi, 7up and fresh watermelon juice. This could provide potential application of P-EBFC as a portable power device.

A sensitive HPLC-FLD method combined with multivariate analysis for the determination of amino acids in l-citrulline rich vegetables

The proposed analytical method reports the separation and quantification of 21 amino acids including l-citrulline from fresh vegetables and commercial juices using a C8 column. Optimal separation conditions for amino acids analysis were obtained with 20 mM sodium acetate (solvent A) and water with organic modifier acetonitrile and methanol (solvent B; 18/50/32 V/V). The ideal pH and column temperature were found to be 5.40 and 35 °C, respectively. The LOD and LOQ values were obtained in the range of 0.02–0.19 ng/mL and 0.04–0.39 ng/mL for all amino acids respectively. Relative standard deviations (RSD) of intraday and interday analysis were found to be <2.7% and 7.9%, respectively. The recovery of amino acids were found be satisfactory for all the tested crops. The developed method was successfully used for the quantification of amino acids in six fresh vegetable juices including watermelon, cucumber, celery, calabaza squash, zucchini squash, yellow squash and commercial juices. Multivariate analysis was used to determine the significant differences in the amino acids profiles. l-citrulline content was highest in fresh watermelon juice (716.57 ± 24.80 μg/mL) and commercial watermelon lime juice (826.48 ± 34.48 μg/mL). The optimized analytical method is rapid, sensitive, accurate and reproducible for analysis of free amino acids including l-citrulline from different vegetable juices and other food products. To the best of our knowledge, this is the first report to separate OPA derivatives of amino acids using C8 column from watermelon, cucumber, zucchini squash, yellow squash, calabaza squash, and celery in a HPLC-FLD system.

Inlet temperature affects spray drying quality of watermelon powder

The effect of the inlet temperature on the quality of watermelon powder after spray drying was evaluated. Inlet temperatures of the drying air of 120, 130, 140, and 150°C maintained water solubility of the watermelon powder at 96%. At 253 µM/g, the ORAC value of the watermelon powder dried at 130°C was the highest among all tested powders. The D&lt;sub&gt;50&lt;/sub&gt; of the watermelon powder dried at 130°C was 18.21 ± 0.22 µm with a span of 1.73 ± 0.038, which was more uniform than that of other powders. The crystallinity of the powder dried at 130°C was higher than that dried at both 120 and 150°C and showed stronger thermal stability. Moreover, watermelon powder dried at 130°C presented a similar aroma as the fresh watermelon juice when being solved. Hence, an inlet temperature of the drying air of 130°C was the optimal temperature for the production of watermelon powder.

Comparison of fresh watermelon juice aroma characteristics of five varieties based on gas chromatography-olfactometry-mass spectrometry

Qualitative and quantitative analysis and odor active value (OAV) calculation were applied to identify the aroma-active compounds of fresh watermelon juice in five varieties: Seedless, Jingxin, Lianfa, Qilin, and Texiaofeng. Principal component analysis and cluster analysis were selected to compare the similarity and difference among watermelons juices. Fifty-five volatiles were identified in watermelon juice in five varieties, among which 6 volatiles were identified for the first time in watermelon. (Z)-6-nonenal, (E, Z)-2,6-nonadienal, (E)-2-nonenal, and (E, E)-2,4-nonadienal contributed greater to aroma profiles than alcohols due to lower threshold through odor active values. It was indicated by principal component analysis and cluster analysis that watermelon juices were separated into three groups, Jingxin, Lianfa-Texiaofeng, and Seedless-Qilin, whose characteristic volatiles were aldehydes, alcohols, and ketones respectively. The average distance between JX and the other varieties was higher than that of others through cluster analysis, indicating that the aroma of Jingxin differed from that of the other four varieties greatly.

Ohmic heating assisted polyphenol oxidase inactivation of watermelon juice: Effects of the treatment on pH, lycopene, total phenolic content, and color of the juice

Fresh watermelon juice was treated at 90 8C by hot-water (HW) and ohmic (OH) treatment (with SS:316 electrodes) for 15, 30, 45 and 60 sec. PPO activity was reduced to 36.15 and 8.87% in 60 sec by HW and OH treatment respectively. The PPO inactivation was fitted to the first order model; the reaction constant (k), D90 obtained was 0.02 s21, 115.1 sec, and 0.062 s21, 37.1 sec for HW and OH treatment respectively. During both the treatments of watermelon juice total phenols (TPC) showed significant change whereas no significant change was observed in lycopene content. Total change in color (DE) during OH treatment was found lesser as compared to HW treatment, hue angle was found to increase at a higher rate in HW than that of OH treatment. Finally it was concluded that PPO of water melon juice can be inactivated rapidly by OH than HW treatment. Practical applications Enzymatic browning and lycopene degradation are the major factors that limit the storage of watermelon juice. High temperatures and processing times employed during thermal processing cause deleterious changes in the color, flavor, and sensory aspects of the product. Therefore, this study was conducted to investigate the comparative effect of ohmic and conventional heating on inactivation of PPO as well as quality changes in watermelon juice so as to suggest a time-efficient alternative that can be explored further for commercial packaging.

Effect of drying methods and maltodextrin concentration on pigment content of watermelon juice powder

The effect of spray/freeze drying and maltodextrin concentration (3%, 5%, 7% and 10%) on pigment retention of watermelon juice powder from three cultivars was investigated. Incorporation of maltodextrin in watermelon juice yielded freely flowable powder. The spray dried powder has less moisture content, low water activity, high dissolution value and less reducing sugar content as compared to freeze dried powder. Lycopene of fresh watermelon juice was 4.58–6.53mg/100g on wet basis (wb) which was increased up to 56.4mg/100g (wb) in spray dried powder and 62.3mg/100g (wb) in freeze dried powder. Variation in instrumental color parameters with maltodextrin levels and dryers revealed that the freeze dried powder have lower ‘L’ value, higher ‘a’ value, higher ‘b’ value, lower ‘hue angle’ and high ‘chroma’ values as compared to spray dried powder. In spray drying lycopene loss was influenced by high air temperature and intensive exposure to oxygen causing degradation of lycopene. The freeze dried powder retained more pigment but powder had high water activity, limited shelf life, low flowability and hygroscopic in nature. Good correlation between colorimetric values and lycopene content was observed in spray dried powder.

Impact of γ-Irradiation on Aroma Flavour, Bio-Active Constituents and Quality Attributes of Water Melon Juice

γ-Irradiation is highly effective in inactivating microorganisms and enzymes activity in various foods and it offers a safe alternative method of food decontamination and maintaining quality. Water melon juice was exposed to γ- irradiation of 1, 3 and 5 kGy at room temperature (25 ± 1°C). With regard to colorimetric parameters the fresh water melon juice was lower than the irradiated samples. There was an improvement in the Hunter color value in irradiated water melon juice compared with fresh samples. The ascorbic acid, other antioxidants measured (DPPH, β-carotene asays, total phenols, flavonoids and antioxidant capacity) showed enhancement on expsoure to γ-irradiation. Microbial studies showed reduction in total bacterial counts in irradiated juice at 5 kGy. γ-irradiation improves microbial decontamination and antioxidant activity as well as colour of the water melon juice (WMJ) without any adverse change in bioactive and volatile compounds qualities. These results support the application of γ-irradiation as a measure of food preservation technique for water melon juice that can be explored commercially to benefit both the producers and consumers.

Analysis of volatile aroma component of fresh watermelon juice by SPME and SAFE with GC-O-MS

In order to compare the different extraction methods on the flavor of seedless watermelon, the volatile aroma component of seedless watermelon were qualitatively and quantitatively analyzed by solid phase microextraction solvent assisted flavor evaporation with GC-O-MS. A total of 46 volatile aroma compounds were identified, mainly consisting of 8 aldehydes, 9 olefine aldehydes, 12 alcohols, 6 ketones, 2 furans, 1 lactone and 2 esters. The important volatile aroma component were hexanal (grass) , 6-methyl-5-Hepten-2-one (honeydew melon and fruity) , (E) -6-Nonenal (fruity) , (E) -2-Nonenal (melon and green) , (E, Z) -2, 6-Nonadienal (cumumber) , (Z) -3-Nonen-1-ol (green and fatty) , (E, Z) -3, 6-Nonadien-1-ol (cumumber) . SPME and SAFE both could extract odor-active compounds of watermelon juice adequately, while SPME could obtain more compounds.

Thermal Degradation Kinetics of Pigments and Visual Color in Watermelon Juice

Thermal degradation of total carotenoids, lycopene and visual colour of watermelon juice was studied at 50–90°C up to 5 h. Total carotenoids content in fresh watermelon juice was reduced from 4.568 to 0.929 mg/100 g, lycopene from 4.403 to 0.82 mg/100 g and Hunter ‘a × b’ value from 251.66 to 89.59 when heated at 90°C for 5 h. First order model explained the degradation behaviour of total carotenoids, lycopene and Hunter ‘a × b’ value evident from correlation coefficient (R2) higher than 0.93. The dependence of degradation rate constant of total carotenoids, lycopene and Hunter ‘a × b’ value on temperature was adequately explained by Arrhenius equation. The activation energies for total carotenoids, lycopene and Hunter ‘a × b’ value were 24.19, 26.46, and 55.47 kJ/mol, respectively. Total carotenoids and lycopene were correlated with Hunter ‘a × b’ value with R2 > 0.99 indicating that visual colour may be used to predict lycopene and total carotenoids contents in watermelon juice.