Melon Slices Research Articles

Drying Kinetics and Thermodynamic Properties of Ultrasound Pretreatment Bitter Melon Dried by Infrared

Determination of drying characteristics of ripe and unripe bitter melon in an infrared dryer at 50, 60, and 70°C with airborne ultrasonic pretreatment with a power of 20 kW for 0, 10, and 20 minutes and a frequency of 20 kHz is the purpose of this study. At the end of drying, among the five used models that fit the moisture ratio data, the Midilli and logarithmic models were selected to properly characterize the drying behavior in the infrared dryer with ultrasonic pretreatment of ripe and unripe bitter melon samples. Moisture transfer from bitter melon samples’ ripeness and early maturity was defined using Fick’s diffusion equation. Then, the Arrhenius equation was utilized to determine the effective moisture diffusivity. Also, the activation energy of unripe and ripe bitter melon slices was reduced with the enhancement in the ultrasound pretreatment time. Water activity (aw) amounts of ripe and unripe bitter melon were achieved at various drying temperatures and ultrasound pretreatment. The trends of the experiment indicate a decrease in enthalpy (ΔH) and entropy (ΔS) amounts of bitter melon with enhancing temperature and ultrasonic. The Gibbs free energy (ΔG) increases with enhancing drying temperature and ultrasonic pretreatment. Specific energy consumption decreased with enhancing drying temperature and ultrasound pretreatment duration for both ripe and unripe bitter melon samples.

Physicochemical and organoleptic properties of hot-air dried oriental melon slices prepared using different physical pretreatments

The oriental melon poses challenges in terms of long-term storage and distribution. Addressing these issues requires an extension of the storage life through appropriate processing. In this study, pretreated hot-air dried oriental melon slices (steamed and freeze-thawed) were prepared, and their physicochemical and organoleptic properties were examined. The control group (CON) consisted of hot-air dried oriental melon slices without pretreatment, while the steamed group (STG) and freeze-thawed group (FTG) consisted of hot-air dried oriental melon slices pretreated using steaming and freeze-thawing methods, respectively. The moisture contents detected in the CON, STG, and FTG groups ranged from 15.96% to 27.30%, with variations of 7.53 to 8.40 °Brix for the soluble solid contents. The CON group showed the highest Hunter color value for lightness (L*) and the lowest value for redness (a*). The texture profile analysis revealed the highest hardness and chewiness in the order of STG > CON > FTG. Considerable differences were observed in springiness and adhesiveness in the FTG group compared to the other groups. The organoleptic evaluation showed that the CON group had the highest sensory scores for overall preference. These findings indicate that the properties of hot-air dried oriental melon slices were influenced by physical pretreatments and that manufacturing these slices without pretreatment is the most effective method in terms of processing simplicity and cost efficiency.

Predicting the Moisture Ratio of a Hami Melon Drying Process Using Image Processing Technology.

For food drying, moisture content and shrinkage are vital in the drying process. This paper is concerned with the moisture ratio modeling and prediction issues of the Hami melon drying process. First, an experimental system was developed; it included an adjustable-power microwave drying unit and an image-processing unit. The moisture contents and the areas of Hami melon slices at different times were sampled in real time. Then, the expression of the moisture ratio with regard to shrinkage was derived by using the Weierstrass approximation theorem. A maximum likelihood fitness function-based population evolution (MLFF-PE) algorithm was then put forward to fit the moisture ratio model and predict the moisture ratio. The results showed that the proposed MLFF-PE algorithm was effective at fitting and predicting the moisture ratio model of the drying process of Hami melon slices.

Experimental study of the process of drying melon slices in a chamber-convection dryer

This article discusses the design features of a chamber-convective drying installation, the principle of its operation and the results of experimental studies of drying ring-shaped melon slices. Based on the analysis of the results obtained, recommendations are given for the use of a drying plant in farms and dehkan farms specializing in the cultivation and processing of melons.

Experimental study of a drying installation for drying melon with IR-radiation

The article presents the results of experimental studies of a newly developed drying installation for drying melon using the convective method in continuous motion with simultaneous exposure to infrared radiation. Experimental studies have established that when passing a chain conveyor in the collector area, melon slices are exposed to infrared rays, which speeds up the drying process. IR rays have a good effect in the initial period of drying, and in the second period, exposure to rays is not necessary. A drying unit with infrared radiation provides high technical and economic indicators for drying ring-shaped melon slices, therefore it is recommended for its use in small and medium-sized farms specializing in the production of dried melon.

Research on the Integration of Intangible Cultural Heritage and Tourism Development under the Background of Rural Revitalization

Lu'an is a famous old revolutionary base area, known as the cradle of the Red Army and the hometown of Generals. The natural and humanistic environment is mainly reflected in its regional characteristics of "Jingjiang Huaijiang", the geographical location of "connecting the east and the west", and the beautiful scenery of "mountains surrounded by Yinghuo". There are many natural and humanistic landscapes and a collection of humanities in the territory. It is understood that there are currently 17 projects in Lu'an that are included in the list of "intangible cultural heritage" of Anhui Province. Among them, Lu opera, Lu'an melon slices production skills, Dabie Mountain folk songs, Shuxi production skills, and willow weaving skills are included in the national "intangible cultural heritage" list. Intangible cultural heritage is a new object of cultural heritage protection and a new way of cultural and social development. Lu'anlai has made certain achievements in the protection of "intangible cultural heritage". With the continuous development of tourism, it has provided good conditions for rural construction. Under the background of comprehensive rural revitalization, "intangible cultural heritage" is the potential resource of rural tourism and cultural industry in the future. At the same time, "intangible cultural heritage" is combined with tourism development. On the basis of protection, display, promotion and promotion, extensive aesthetic education is carried out to achieve the purpose of truly protecting "intangible cultural heritage", and at the same time, to achieve the purpose of continuously inheriting the cultural lifeline.

Drying of Melons in a Solar Tunnel Dryer: The Effect of Ascorbic Acid Solution on Drying Kinetics and Color Parameters

This study aims to present the performance of the solar tunnel dryer, which is required for the drying of two different types of melon with and without pretreatment. The solar tunnel dryer used in the study was built at Isparta University of Applied Sciences, Department of Agricultural Machinery and Technologies Engineering. The dryer consists of a flat plate solar collector, drying tunnel, solar cell module and a small axial fan. During the drying process, solar radiation, drying air temperature, relative humidity and air velocity were measured continuously in different parts of the dryer. At the same time, the mass loss of the melon slices was measured every two hours during the drying period. On the other hand, colour measurements were made on untreated and pre-treated melon slices, fresh and after drying, before and after the trials. Fresh melon samples were washed with tap water, and cut in half with a knife, the core in the middle was removed and sliced by hand in a half-moon shape without peeling before pre-treatment. 1% ascorbic acid was applied to the fruits as a pretreatment. After the preparations, the solar tunnel drying behaviour of untreated and pretreated sliced melon samples was investigated. Drying characteristic curves were evaluated according to five different mathematical models. In this study, it was determined that the L*, a* and b* values of melon varieties were preserved without pretreatment. The lowest total color change was observed in the bleached samples in both types of melon samples.

Microbiological Safety of Cut Melons Sold in Portuguese Retail Markets: A Pilot Study.

Due to the increasing consciousness of a healthy diet and pursuit of convenience among consumers, the market for fresh fruit is on the rise, and the melon is among the most welcome of fruits for its sensory attributes and nutritional properties. Consumption safety of cut fruit remains an issue of concern that may affect public health. This study aimed to perform the microbiological characterisation of a melon, Cucumis melo L. var. “Piel de Sapo”, cut by retailers, wrapped in plastic cling film and kept at room temperature in local fruit shops. In addition, the possible transfer of relevant foodborne pathogens, during slicing, from the peel to the interior of the melon, and bacterial growth, were also evaluated when the melon slices were stored at abusive temperatures for 2 days. In this pilot study, a low number of samples were characterised microbiologically (26 cut melons), and some isolates were identified by 16S rRNA sequencing. No Listeria spp. or Salmonella spp. were detected in any of the samples, while Escherichia coli and Staphylococcus aureus were present in four and six out of twenty-six samples, respectively. Following artificial contamination of melons with cocktails of Salmonella spp., E. coli and Listeria monocytogenes, it was observed that, despite the smaller number of L. monocytogenes recovered, all the pathogens were transferred from the contaminated peels to the interior of the melons. Furthermore, over storage time, significant differences were observed (p < 0.05) between the counts obtained from melon slices immediately after cutting (0 h), and after 24 and 48 h at 20 °C, with an increase of about 4 log CFU/g in all the pathogens. In conclusion, some cut melons classified as microbiologically unacceptable or unsatisfactory are being sold in local fruit shops in the Porto Metropolitan Area, Portugal. Although absent in the samples analysed, Salmonella spp. and L. monocytogenes, if present, can be transferred from the outside to the inside of the fruit by the cutting blade and, if not consumed immediately and stored at abusive temperatures, this ready-to-eat product poses a risk of infection. This pilot study, performed for the first time in Portugal under these conditions, clearly demonstrates the need for education campaigns to alert local sellers and consumers of the risk posed by cut melons.

MATHEMATICAL MODELLING AND OPTIMIZATION OF MELON SLICE DRYING WITH RESPONSE SURFACE METHODOLOGY IN A HEAT PUMP DRYING SYSTEM

The objective of this study was to optimize the process conditions (in terms of air temperature, air velocity and thickness of the slices) using response surface methodology (RSM) to achieve minimum specific energy consumption and maximum moisture diffusivity during drying of melon slices with a closed loop heat pump drying (HPD) system. An optimum drying temperature of 45 °C, air velocity of 1 m/s and slice thickness of 5.04 mm were recommended with following predicted responses close to experimental values: drying time 216.58 min, total energy consumption 2.94 kWh, coefficient of performance heat pump (COPhp) 3.08, coefficient of performance system (COPws) 2.75, specific moisture extraction rate (SMER) 0.22 kg/kWh, drying rate 2.53, L* value 82.53, a* value -1.83 and b* value 25.82. The most suitable models to represent the drying behavior of optimum melon slices was chosen Wang &amp; Sing. Effective moisture diffusivities (Deff) of the melon slices were ranging from 7.075E-10 - 1.843E-07 m2s-1 and increasing drying air temperature, drying air velocity and slice thickness led to an increment of Deff.

Bioaccessibility of total phenolics and antioxidant activity of melon slices dried in a heat pump drying system

Bioaccessibility of total phenolics and antioxidant activity of melon slices dried in a heat pump drying system

A comparative study of bioactive compounds, antioxidant activity and phenolic compounds of melon (Cucumis meloL.) slices dehydrated by oven, microwave and infrared systems

Fresh melon (control) contained 0.07 µg/g total carotenoid, 17.56 mg GAE/100 g total phenol, and 8.21 mg QE/100 g total flavonoid. Antioxidant activity value of fresh melon (control) was 0.15 mmol TE/100 g while total carotenoid amounts of dehydrated melons vary between 0.05 µg/g (oven) and 0.29 µg/g (microwave), and total flavonoid amounts of dehydrated melons were measured between 42.50 (microwave and infrared) and 43.21 mg QE/100 g. Total phenol contents of dehydrated melon slices were identified between 101.96 (infrared) and 150.18 mg GAE/100 g (microwave). While the contents of 3,4-dihydroxybenzoic, (+)-catechin, caffeic, syringic, rutin, p-coumaric and ferulic acid of melon samples dehydrated in the oven were higher than those of melons dehydrated in microwave and infrared, only gallic acid, 3,4-dihydroxybenzoic, (+)-catechin, and ferulic acid contents were slightly higher than those of melons dehydrated in infrared. The highest component was determined in melon dehydrated in the oven, followed by infrared and microwave in decreasing order. Practical applications Melon is one of the most consumed fruits worldwide. Dehydration is one of the main postharvest processes. Drying studies were carried out on determining several quality indexes. Dehydrated melon is prepared as a product enriched with bioactive components. In this concept, melon has become a preferred and consumed food item in the world in terms of taste due to its high sweetness and total phenolic. Especially fruits have an important role in human nutrition due to their many bioactive and phenolic compounds.

Evaluation of melon drying using hyperspectral imaging technique in the near infrared region

The evaluation of the melon drying process under different pretreatments using hyperspectral images in near infrared (HSI-NIR) is presented as a quick and non-destructive means. Hyperspectral images of melon slices (3.0 cm × 3.0 cm x 0.3 cm) were obtained for different drying times. Principal Component Analysis applied to the images of cross sections of the dried samples without pre-treatment indicated that the water evaporation occurred unidirectionally. PLS models were generated for each drying pretreatment condition according to the moisture content based on their respective reference values. Prediction errors (RMSEP) obtained for these models were 3.79; 3.69; 3.24 and 2.98% moisture content under the following conditions, respectively: no pretreatment, ultrasound, vacuum, and the combination of vacuum and ultrasound. Chemical maps reveal that the use of vacuum and the combination of vacuum and ultrasound result in uniform drying, corroborating the results obtained by the drying kinetic curve, indicating that these pretreatments facilitate water diffusion in the samples.

QOVUN BO`LAKLARINI QURITISH UCHUN MEXANIZASIYALASHGAN KAMERALI-ZANJIRLI QURITISH QURILMASINING ZANJIRLI UZATMASINI HISOBLASH

The article deals with the calculation of the drive and chain transmission of the newly created mechanized drying plant for drying melon slices. The essence of the utility model: the machine contains a horizontal tunnel chamber, inside which is mounted a chain conveyor with driving and driven sprockets, load-carrying elements, the IR emitters with reflectors on top of the camera mounted electric air heater, fan, an annular heat exchanger equipped with inlet and outlet nozzles of the drying agent. On the branches of the conveyor chain, lodgments with folding clamps are mounted, on which load-bearing elements are fixed, which are used as wooden poles. The calculation of the drive and chain transmission of the drying plant conveyor was carried out according to the existing method according to the scheme shown in the figure. Thus, the main parameters of the drive and chain transmission parts of the mechanized chamber-chain drying plant for drying melon fruits were determined by calculation

Effect of Ultrasonic Pretreatment on Melon Drying and Computational Fluid Dynamic Modelling of Thermal Profile.

SUMMARY Research background: Drying is one of the most traditional processes of food preservation. Optimizing the process can result in a competitive product on the market regarding its price and quality. A common method in use as a pretreatment to drying is ultrasound. The goal of this work is to analyze different drying methods with and without applying ultrasound (US) pretreatment, on heat and mass transfer, simulating numerically the temperature profile by computational fluid dynamics (CFD). Experimental approach: The melon slices were pretreated with ultrasound for 10 (US10), 20 (US20) and 30 (US30) min at 25 kHz, and the water loss and solid gain were evaluated. Samples were dried at different temperatures (50, 60 and 70 °C). The effective diffusivity was estimated, and experimental data were modelled using empirical models. The airflow in the dryer and the temperature profile in the melon slice were simulated via computational fluid dynamics (CFD). Results and conclusions: Ultrasound pretreatment reduced the drying time from 25% (samples US20 and US30 at 50 °C) to 40% (samples US20 and US30 at 70 °C). The two-term exponential model presented the best fit to the experimental data, and the diffusivity coefficients showed a tendency to increase as the time of exposure of the melon to ultrasonic waves increased. Pretreatment water loss and solid gain behaviour and drying kinetic and diffusion data were used to choose the best experimental conditions to be simulated with CFD. The heat transfer modelling through CFD showed that the temperature distribution along the melon slice was representative. Therefore, the profile obtained via CFD satisfactorily describes the drying process. Novelty and scientific contribution: The use of simulation tools in real processes allows the monitoring and improvement of existing technologies, such as food drying processes, that involve complex mechanisms, making it difficult to obtain some data. Application of CFD in the drying processes of fruits and vegetables is still very recent, being a field little explored. There is no record in the literature that uses CFD in the drying of melon.

Kinetics of nutrient change and color retention during low‐temperature microwave‐assisted drying of bitter melon ( Momordica charantia L.)

The changes in nutrient (phenolics and vitamin C) and color of bitter melon slices, during microwave-assisted drying (MWAD) at different microwave power values (1.5, 3.0, and 4.5 W/g) and air temperatures (20, 25, and 30°C) are reported. Fits of the experimental data to a semi-empirical mathematical model were used to determine the half-lives of the nutrients. Color change during drying was similarly characterized using CIELAB color space parameters. The rates of nutrient degradation and color change increased with an increase in microwave power, and drying temperature, but the drying times decreased significantly. The total electrical energy consumed under various drying conditions was measured. Although a microwave power of 1.5 W/g and an air temperature of 25°C resulted in the highest levels of nutrient retention, the drying time and process energy consumption were relatively high. In comparison, the drying conditions of 4.5 W/g and 30°C provided an acceptable compromise. Practical applications Low-temperature MWAD is a promising alternative to conventional drying for food that contains temperature-sensitive nutrients. This article provides a methodology for analyzing the kinetics of nutrient and color change during a MWAD process. A 32 factorial design was used to derive predictive correlations for drying time, nutrient half-life, time constants characterizing color change, and electrical energy consumed during the drying process. The relative influences of microwave power and drying temperature could be readily discerned using these correlations. The reported study will help in developing and optimizing microwave drying processes for a variety of food products.

Numerical Modeling of Air Flow in a Cabinet Dryer Equipped by Deflector Plates

Abstract In this study, air deflector plates were used in order to increase the air elapsed time in the chamber. The air flow pattern was simulated using computational fluid dynamics. The geometry of the chamber was produced in 2D and meshed by triangular and quadrilateral elements, boundary conditions were defined and the governing equations solved. Modeling of flow without any deflectors depicted the air flowed to the chamber conducted to the outlet without any distortion. Air vortices were generated when the deflectors defined in model. To evaluate the influence of deflectors on drying period, constructed plates installed in the dryer chamber and melon slices were dried when deflectors used or not. Simulation results showed magnitude of the air velocity was increased and temperature uniform distribution developed on the surface of trays. The outlet temperature was also decreased up to 10 % and drying time reduced to 22 % when the deflectors were employed.

Optimization of Process Variables for Retention of Functional Properties of Bitter Melon (Momordica Charantia L.) and its Shelf-Life Extension

This study was carried out to investigate the effect of sodium hypochlorite (NaClO), hydrogen peroxide (H2O2) and soaking time on vitamin C, carotenoid, antioxidant activity and total phenolic content for optimizing the pre-treatment for minimal processing of bitter melon slices and to evaluate its shelf life at different storage conditions. Fresh-cut bitter melon slices were given post-cutting treatment of wash solution containing NaClO(25-500ppm) and H2O2 (1-5%) solution for different time intervals (10-120 minutes). The treated samples were analyzed for Vitamin C content, carotenoid, DPPH inhibition activity, ABTS inhibition activity and total phenolic content (TPC) using Central Composite Rotatable Design (CCRD). The optimum condition for soaking achieved by CCRD was NaClO (25 ppm), H2O2 (1%) and soaking time (56.32 min). The minimally processed bitter melon at optimized wash water treatment was packed in LDPE pouch of 0.1 mm thickness and were evaluated for shelf-life under modified atmospheric packaging, MAP 1 (5% O2, 25% CO2 &amp; 70% N2) and MAP 2(10% O2, 20% CO2 &amp; 70% N2) stored at temperature of 5, 20 and 35°C, respectively. Based on the microbiological, colour and textural analysis, MAP 1 was found to be better compared to MAP 2 and the shelf-life of fresh-cut bitter melon slices was prolonged up to twenty-eight days of storage.

Evaluation of ultrasound pretreatment and drying methods on selected quality attributes of bitter melon (Momordica charantia L.)

ABSTRACTRecently, numerous attentions have been drawn to bitter melon (Momordica charantia L.) processing due to its outstanding pharmacological properties. Fresh and ultrasound pretreated bitter melon slices were subjected to hot air drying (HAD) and radio frequency assisted hot air drying (RFHAD) in this study. Quality attributes of the dried samples were compared in terms of moisture content, water activity, glass transition temperature, color, rehydration ratio, and content of chlorophyll, ascorbic acid, and total phenolic. Compared with HAD process, results showed that the use of ultrasound pretreatment and RF heating accelerate water loss during drying processes, and then contribute to a shorter drying time, a lower water activity and higher glass transition temperature of dried samples. It also showed RFHAD had better color exhibition, higher retention of chlorophyll, ascorbic acid, and total phenolic due to uniform heating and shorter drying time. Additionally, ultrasound pretreatment greatly improved the rehydration capacity and total phenolic retention. Therefore, considering the quality attributes and drying time, ultrasound pretreatment and radio frequency drying would be very promising alternatives for food processing.

Analysis of drying of melon in a solar-heat recovery assisted infrared dryer

Infrared drying systems are popular in terms of high heat and mass transfer. By using an infrared dryer, it is possible to catch fast heating and short drying time in comparison to the other drying methods. But it consumes a high amount of energy. Therefore, a new type solar air collector (SAC) and air to air heat recovery unit were added to the infrared dryer to reduce specific energy consumption. The general aim of this study is to analyze heat and mass transfer characteristics of the dryer and three-dimensional (3-D) computational fluid dynamic (CFD) simulation and to investigate drying kinetics of melon slices. Experiments were performed at 50°C and 60°C melon’s surface temperature and 0.5m/s air velocity. Melon slices were dried from 9g water/g dry matter to 0.044g water/g dry matter moisture content. The effective moisture diffusivity (De) values varied from 8.25×10−10 to 1.24×10−9m2/s. The average mass transfer coefficient (hm) values increase from 8.53×10−8m/s at 50°C to 1.47×10−7m/s at 60°C. Heat recovery unit has a key role in this system and it provides 23–28% of total input energy. Average solar air collector efficiency was calculated as 50.6%. Obtained theoretical and experimental results are in line with each other. This study shows the successful and efficient combination of solar energy, infrared energy and heat recovery in food processing.

Planning the Experiment of Treated Melon Slices during the Drying

The analysis of planning the experiment of treated melon slices during the drying will help in decision of such matters as creation of large powered equipments and effective methods of drying automation of control and regulation of drying process