Dehydration Of Fruits Research Articles

A Study and Development of the Control System of Fruit Dehydration Machine by Biomass Energy

This article presents the study and development of the control system of fruit dehydration machine by biomass energy in which manual control system was upgraded to the Auto one. Study results revealed that Auto control system required less operation time for as much as 1.30 hour. By comparing energy consumption of the two systems, the upgraded system required less energy approximately 751.30 baht/month and 9,016.32 baht/year. When the break-even point is taken into consideration, this system upgrade could payback after 3.33 year. The author really hopes that this study can be used as a guideline for those interested or involved in the development fruit dehydration machine.

The shrinkage of orange slices during microwave drying and ohmic pretreatment

The present research was an attempt to investigate the effect of ohmic pretreatment on the shrinkage of orange slices during the microwave drying and check the effect of this heating process on the shrinkage percentage of the samples. Thomson oranges were chopped into 4-mm-thick slices and were then arranged in a way that they can fit into the ohmic heating system. The ohmic heating system consisted of a 10-mm-thick rectangular glass cell (11 × 8 × 15 cm3) with two 8 × 15 cm stainless steel electrodes and a voltage regulator. Samples were tested at three voltage gradients (30, 50, and 70 V) for 3, 5, and 7 min. After the heat treatment process, the orange slices were subjected to microwave drying at three power levels (90, 360, and 900 W). During the microwave drying process, samples were photographed and weighed at 1-min intervals to check the shrinkage percentages. The experiment was carried out with three replicates. The results showed that the use of ohmic heating system as pretreatment leads to a decline in the moisture content of orange slices. In other words, an increase in duration of heating (from 3 to 7 min) intensifies the moisture content reduction rate. During the microwave heating process, any rise in microwave power (from 90 to 900 W) led to intensification of orange slice shrinkage level. Practical applications The present research was carried out in an attempt to increase productivity of dehydration in the industrial sector and also in the fruit dehydration industry. This research was also an attempt to investigate and predict the shrinkage rate of orange slices subjected to microwave dehydration and investigate the effect of ohmic pretreatment on the shrinkage percentage of the specimens in an attempt to figure out if this method can be used as an alternative to other industrial methods.

A water drop-shaped slingshot in plants: geometry and mechanics in the explosive seed dispersal of Orixa japonica (Rutaceae).

In angiosperms, many species disperse their seeds autonomously by rapid movement of the pericarp. The fruits of these species often have long rod- or long plate-shaped pericarps, which are suitable for ejecting seeds during fruit dehiscence by bending or coiling. However, here we show that fruit with a completely different shape can also rely on pericarp movement to disperse seeds explosively, as in Orixa japonica. Fruit morphology was observed by hard tissue sectioning, scanning electron microscopy and micro-computed tomography, and the seed dispersal process was analysed using a high-speed camera. Comparisons were made of the geometric characteristics of pericarps before and after fruit dehiscence, and the mechanical process of pericarp movement was simulated with the aid of the finite element model. During fruit dehydration, the water drop-shaped endocarp of O. japonica with sandwich structure produced two-way bending deformation and cracking, and its width increased more than three-fold before opening. Meanwhile the same shaped exocarp with uniform structure could only produce small passive deformation under relatively large external forces. The endocarp forced the exocarp to open by hygroscopic movement before seed launching, and the exocarp provided the acceleration for seed launching through a reaction force. Two layers of water drop-shaped pericarp in O. japonica form a structure similar to a slingshot, which launches the seed at high speed during fruit dehiscence. The results suggest that plants with explosive seed dispersal appear to have a wide variety of fruit morphology, and through a combination of different external shapes and internal structures, they are able to move rapidly using many sophisticated mechanisms.

Efecto del retraso entre la cosecha y el inicio de enfriamiento sobre la calidad de frutos de piña

Introducción. Con frecuencia, la fruta de piña que se cosecha, no puede ser enfriada y empacada inmediatamente, debido a la distancia que existe entre el campo hasta la planta empacadora. La industria indica que seis horas es el tiempo máximo conveniente, pero no hay información publicada al respecto. Objetivo. Determinar el efecto del retraso en iniciar el enfriamiento sobre la calidad de piña (Ananas comosus) var. Dorada Extra Dulce, con simulación de transporte. Materiales y métodos. Se realizaron 4 ensayos en diferentes zonas y épocas (seca y lluviosa). La fruta recién cosechada fue expuesta a temperatura ambiente durante 6, 12, 24 y 48 horas, luego de estos períodos, cada lote de fruta fue desinfectado con cloro a razón de 150 mg.l-1. Se le aplicó fungicida prochloraz 300 mg.l-1, se enceró (cera con base de aceite vegetal), se enfrió por aire forzado durante 4-5 horas hasta alcanzar 12-13°C. Se realizó luego una simulación de transporte y finalmente se almacenó por 21 días a 7,5°C y 85-90% HR. Se evaluó el impacto de los tratamientos sobre variables de calidad: pérdida de peso, color externo e interno, moho en pedúnculo, deshidratación parcial, translucidez, firmeza, acidez y sólidos solubles. Resultados. Después de 12 horas de retraso en el enfriamiento, la calidad de la fruta disminuyó, con un impacto más evidente en la deshidratación, el desarrollo de moho y reducción en la firmeza de la pulpa. El color externo e interno, la translucidez, la acidez titulable y los sólidos solubles totales no se vieron afectados. Conclusiones. El retraso del enfriamiento tuvo un impacto negativo en la calidad de la fruta de piña, especialmente en el desarrollo de moho y la deshidratación parcial de la fruta y un impacto menor en la firmeza de la pulpa. Bajo las condiciones del presente estudio, el retraso máximo permitido en el enfriamiento de la fruta fue de 12 horas.

Mass Transfer During Osmotic Dehydration of Fruits and Vegetables: Process Factors and Non-Thermal Methods

Osmotic dehydration of fruits and vegetables is a slow process due to resistance in mass transfer (MT). This resistance can be modified by varying the osmotic solution or process conditions, or by employing non-thermal treatments (NTT). Some NTT modify the tissue structure by formation of pores in the cell membrane (such as pulse electric fields) or microchannels (such as ultrasound and osmosonication), and others increase the contact surface area with the tissue through a decrease in atmospheric pressure (such as vacuum pulses) or an increase of the system pressure (such as high hydrostatic pressures). Changes in the rate of MT caused by modifications in experimental conditions can be described with mathematical models, such as Fick’s second law. The aims of this review are to analyze the different factors that modify MT rate during osmotic dehydration, examine the application of NTT to modify MT, and to study models that describe these processes.

EFFECT OF ULTRASOUND AND ACID PRETREATMENTS DURING DEHYDRATION ON QUALITY PROPERTIES OF QUINCE

Several methods are employed to remove the moisture from organic or non-organic materials, in a variety of industrial applications. Among all, dehydration of fruits is an alternative to decline post-harvest loss of fruits and also a process to produce dried fruits, which can be directly consumed or become part of foodstuffs like cakes, and many others. In particular, drying provokes a series of changes in materials, such as oxidation, browning, or loss of nutritional-functional properties. Ultrasound is famous to have a significant effect on the rate of various processes. Quince is a fruit which is rich in polyphenols, organic acids, and amino acids with important health benefits. The present study examined the effect of ultrasound and blanching pre- treatments prior to convective drying on quality properties of dehydrated quince slices. A completely randomized design was used to address the effect of time of sonication (10−30 min), temperature (40−60°C), and anti-browning agents including acetic, citric, and ascorbic acids as well as distilled water on quality properties of dehydrated quince slices. The obtained results revealed that the shortest drying time (270.33±35.59 min) and the highest total phenolic content (57.29±12.72 mg GAE/ml) were recorded for samples exposed to the ascorbic acid solution. Comparison of the pre-treated and control samples indicated that the highest rehydration ratio (2.75±0.29 %) was achieved by blanched samples in acetic acid solution. The use of citric acid solution led to the highest score in the taste (3.45±1.1), color (3.84±0.9), and texture (3.47±1.02) of quince slices on the basis of a 5- point hedonic scale. The obtained results depended on both ultrasound and the type of blanching solution. Citric and acetic acid samples indicated the highest values of the sensory evaluation and water loss, respectively.

An innovative hybrid-solar-vacuum dryer to produce high-quality dried fruits and vegetables

Food drying uses much energy and is considered a high carbon footprint process. Solar drying is sustainable, but the dryers must be improved to produce high-quality foods in short times. In this study, a hybrid-solar vacuum dryer was designed, built, and applied to fruit dehydration. A solar heater was coupled to a thermally insulated reservoir with electrical resistances to provide hot water at 90 °C as the indirect heating medium. Drying chambers with a full capacity of 4 kg of sliced food were operated under vacuum or vacuum pulses (conductive multiflash drying). Banana slices could be dried with the most basic equipment configuration (vacuum chamber, vapor condenser, and vacuum pump), resulting in homogeneous and crispy snacks. The dryer was also tested for persimmons and carrots. The drying of all the fruit and vegetable samples resulted in dried and crisp products in 3–4 h, depending on the drying temperature, and the use of continuous electric support for temperatures higher than 70 °C. The hybrid solar dryer operating under vacuum is an innovative and clean technology that results in high-quality products and has excellent potential to be used in small farms.

Determination of α‐dicarbonyl compounds and 5‐hydroxymethylfurfural in commercially available preserved dried fruits and edible seeds by optimized UHPLC–HR/MS and GC–TQ/MS

Thermal processing, Maillard reaction, and caramelization favors the formation of α-dicarbonyl compounds during thermal dehydration of fruits and edible seeds roasting, which are extensively discussed as precursors of different undesirable compounds such as 5- hydroxymethylfurfural. Different studies have focussed on prevalence of α-dicarbonyl compounds and determination of 5-hydroxymethylfurfural from simple food matrices. However, still extensive studies are needed to be carried out for their determination from these complex food matrices for human awareness. In this study, the prevalence of α-dicarbonyl compounds and 5-hydroxymethylfurfural was investigated using an optimized UHPLC–HR/MS after ortho-phenylenediamine derivatization, and by an optimized GC–TQ/MS, respectively. Eight different categories of dried fruits and four categories of edible seeds were analyzed for prevalence of 3-deoxyglucosone (3-DG), glucosone (G), glyoxal (GO), methylglyoxal (MGO), and 5-hydroxymethylfurfural (5-HMF). Significantly higher prevalence of 3-DG was shown in raisins with concentration of 43.36 ± 1.16 mg/kg; however, 5-HMF has shown significantly higher concentrations (165.90 ± 4.41 mg/kg) in dried mango category. Moreover, edible seeds category has shown higher prevalence of 3-DG with 3.80 ± 0.28 mg/kg in hazelnuts and 75.44 ± 3.13 mg/kg of 5-HMF from peanuts. Interestingly, higher concentration of 5-HMF was determined in all analyzed samples than 3-DG, indicating a relation between the conversion of α-dicarbonyl compounds into 5-HMF during the dehydration process or roasting of dried fruits and edible seeds, respectively. Moreover, these methods were also validated in terms of recovery, specificity, accuracy, limit of detection, limit of quantification, and relative standard deviation for all analyzed compounds. Practical Application This study has conducted to get awareness about formation of harmful compounds during processing of fruits and edible seeds in order to get them preserved for long time and to increase their taste properties. This study has clearly stated the prevalence of alpha-dicarbonyl compounds and 5-hydroxymethylfurfural which can later convert into more toxic compounds upon changes in their conformation. Hence, the routine or excessive usage might be health hazardous for us. Moreover, companies should also apply more careful processing conditions posing less effect on fruit matrix.

Moisture sorption properties of two varieties of dehydrated mango slices as determined by gravimetric method using Guggenheim–Anderson–de Boer model

The moisture sorption isotherms for oven dried mango were constructed gravimetrically at three different temperatures of 25°C, 30°C, and 35°C, and relative humidity ranging 8.3%–97.0%. The Guggenheim–Anderson–de Boer model was used to fit sorption data and constant equations determined using nonlinear regression analysis. The isotherms had J-shaped curve that represents type III isotherms characterized by sugar-rich products. At increased temperatures, it was observed that equilibrium moisture content increased and crossing effect of isotherm curves was observed with a corresponding increase in water activity. A substantial increase in equilibrium moisture content was observed above water activity of 0.6. Monolayer moisture content of between 8 and 9.6% was predicted for dried slices where the lowest value indicated that moisture content should not be lower than 8.0% to avoid unnecessary energy consumption. For assured microbiological stability, the safe storage moisture content for dried mango should be maintained at approximately 15% or less that corresponded to 0.6 water activity. Practical applications Dehydration of fruits has been utilized as one of the most effective value addition procedures for extending their shelf-life. However, exposure to high drying temperature and significant loss of moisture in fruits cause irreversible stresses in the cellular structure of the fruits and may lead to robust textural changes especially during storage. This research finds practical application in shelf-life estimation and prediction of storage stability of the mango varieties. Additionally, the results can be used as a guide in product development and process design for dried mango slices.

Application of Osmotic Dehydration and Ultrasound to Enhance Hazelnut Oil Extraction

Hazelnut oil is a valuable product which can be used in various applications not limited to food processing, cosmetic product, and pharmaceutical industry. Traditionally, heating process is used to remove the moisture in various nuts and seeds prior to oil extraction stage in the industry which is relatively energy consuming. In this study, osmotic dehydration which is normally used as a pretreatment in fruit dehydration process was applied as a low-energy moisture removal method during the ultrasound-assisted extraction of oil from hazelnut. The effects of ultrasound amplitude, concentration of osmotic solution, and dehydration time on the yield and characteristics of hazelnut oil obtained were investigated in this study. Concentration of osmotic solution and dehydration time showed more significant effects on water removal as compared with ultrasound amplitude. Higher oil yield of 93% was achieved with the introduction of osmotic dehydration as pretreatment without negative impacts on quality of oil as compared with 88% oil yield in extraction without dehydration aid. The values for quality of oil obtained were in the range of 25–40 g/100 g oil, 0.5–1.1 g/100 g oil, and 2–6 mEq/kg for iodine, free fatty acid, and peroxide values, respectively. All the values were in the range of edible oil standard. Therefore, osmotic dehydration is a promising pretreatment method to enhance oil yield during extraction process in food industry.

Dehydration of wolfberry fruit using pulsed vacuum drying combined with carboxymethyl cellulose coating pretreatment

Drying is one of the oldest and most important food preservation techniques but requires promotion to maintain the quality of products. In this paper, pulsed vacuum drying (PVD) combined with carboxymethyl cellulose (CMC) coating pretreatment was employed as a new approach to improve the drying efficiency and produce dried wolfberry with acceptable quality. To achieve these goals, its influence on drying characteristics, energy consumption, drying shrinkage, color, total polysaccharide content and total polyphenol content in dried wolfberry fruit were comparatively evaluated with PVD and convective drying with hot air (CDHA). The results showed that PVD combined with CMC coating pretreatment allowed significantly higher drying efficiency, lower energy consumption, less drying shrinkage and better preservation of color, total polysaccharide content and total polyphenol content in wolfberry fruit (p ≤ 0.05). Increasing CMC concentration from 0.5% to 3.0% (w/w) resulted in an improved drying efficiency and product quality, and reduced energy consumption, the optimal CMC concentration was 2.0% (w/w). Overall, PVD combined with CMC coating pretreatment could be considered as an effective approach to improve the quality of the dried wolfberry fruit and reduce energy consumption.

Influence of Osmotic Dehydration and Method of Drying on the Quality of Aonla Fruit

Osmotic dehydration of aonla fruit was carried out to determine the Influence of osmotic solution and method of drying on the quality of aonla fruit. The destined aonla fruits with and without blanching were immersed in the mixture of salt and sugar solution. The salt concentration of the osmotic solution was kept constant (100 g) and the sugar concentrations were varied to bring the concentrations to 35, 45 and 55°B maintaining a fruit to syrup ratio of 1:3 by weight. The observations were recorded to study the influence of osmotic solution and time on water loss and solid gain. The subsequent drying was carried in hot air and vacuum driers at 50±5°C to a safe storage moisture level of 0.35 kg of water per kg of dry matter. The results showed the maximum water loss of 48.55% recorded for blanched fruit osmosed at 55°B and the minimum (27.61%) in unblanched fruit osmosed at 35°B. The solid gain was observed to be maximum (23.4%) in the blanched fruit compared to unblanched fruit (9.94%) at respective concentrations. Subsequent drying showed that drying was in falling rate and time taken was higher for untreated compared to treated. The blanching and method of drying had a significant effect on the quality of fruit. Colour was found better (Bright greenish-yellow) in blanched vacuum dried fruit followed by unblanched vacuum dried. The maximum amount of ascorbic acid was noticed in the freshly vacuum dried fruit (1780.2 mg/100 g) compared to osmosed fruits (534.8 to 1369.6 mg/100 g). Total sugar was found maximum in the osmosed vacuum dried fruit (82.2%) fruit compared to fresh once (24.6%) but the drying method had no significant effect on the retention of sugars. The mean scores for sensory showed that overall acceptability was higher for blanched vacuum dried fruit followed by unblanched vacuum dried fruits.

Optimisation of osmotic dehydration process for aonla (Emblica officinalis) fruit in the mixture of salt-sugar solution

The osmotic dehydration of aonla fruit was carried out to optimize the time of the osmosis in the mixed solution of sugar and salt at the room temperature. The destined aonla fruits with and without blanching were immersed in the mixture of salt and sugar solution. The salt concentration of the osmotic solution was kept constant (100 g) and the sugar concentrations were varied to bring the concentrations to 35, 45 and 55o Brix maintaining a fruit to syrup ratio of 1:3 by weight. The observations were recorded to study the influence of osmotic solution and time on water loss and solid gain. The results of osmotic dehydration showed the maximum water loss of 48.55 per cent recorded for blanched fruit osmosed at 55o B and the minimum (27.61%) in unblanched fruit osmosed at 35oB. The solid gain also was observed to be maximum (23.4%) in the blanched fruit compared to unblanched fruit (9.94%) at respective concentrations. The optimization process carried out using Design expert software showed the highest desirability of 0.785 for blanched aonla fruit osmosed at 55 oB.

KEHILANGAN AIR DAN PENAMBAHAN PADATAN YANG TERJADI SELAMA PROSES DEHIDRASI OSMOTIK BUAH NAGA

Osmotic dehydration is a method that can be used in the pretreatment of drying by immersing the material in a hypertonic solution. The purpose of this study was to examine the effect of concentration and temperature of the osmotic solution on water loss and solid gain to dragon fruit pieces during the osmotic dehydration process. Dragon fruit slices were immersed in osmotic solution with different concentration and temperature solution (30 oBrix, 50 oBrix, and 70 oBrix, as well as 30 oC, 40 oC, and 50 oC). The WL value for the concentration of 30 oBrix solution varies from 17.42% to 25.26%, for a 50 oBrix concentration is 32.84% to 50.38%, and for a 70 oBrix concentration is 39.89% to 57.99% . Thus, changes in the level of WL, concentration and temperature of the solution, where the higher the concentration and temperature of the solution, the greater the WL of the material. Meanwhile, for SG on materials, values ​​ranged from 2.092% -10.010%. Based on the calculation of the Azuara model, the WL values ​​ranged from 21.551% -75, 187% and 3.899% -17.575% for the SG value. The coefficient of determination for the calculation of the Azuara model is 0.938 - 0.992, thus the Azuara model can be said to be feasible for modeling the WL and SG values ​​on osmotic dehydration of dragon fruit.

Mass transfer modelling in ultrasound assisted osmotic dehydration of kiwi fruit

In this study, the effect of ultrasonic pre-treatment on osmotic dehydration of kiwi slices was investigated. Kiwi fruit slices were subjected to ultrasonic pre-treatment in a sonication water bath at a frequency of 25 kHz for 20 min. Osmotic dehydration of ultrasonic pre-treated samples were conducted for a period of 300 min in 60 Brix sucrose solution. The kinetics of moisture loss and solute gain during osmotic dehydration were predicted by fitting the experimental data with Azuara's model and Weibull's model. The effects of ultrasound application on water loss, sugar gain, effective moisture diffusivity and solute diffusivity of the samples were analysed. The osmotic dehydration process showed a rapid initial water loss followed by a progressive decrease in the rates in the later stages. From the Azuara's model, the predicted equilibrium water loss value for ultrasound pre-treated sample was 58.4% (wb) at 60°C that was nearly 16% higher than the samples treated under atmospheric conditions. Fitting of Weibull model showed that the ultrasound pre-treated and untreated samples had shape parameter (βw) ranging between 0.570–0.616 and 0.677–0.723 respectively. The lower values of shape parameter indicated that sonication caused accelerated water loss resulting faster dehydration rate. Results indicated that the effective moisture diffusivity and solute diffusivity was enhanced in ultrasonic pre-treated samples. The effective moisture diffusivity during osmotic dehydration of ultrasonic pre-treated samples was ranged between 5.460×10−10–7.300×10−10 m2/s and solute diffusivity was varied between 2.925×10−10–3.511×10−10 m2/s within the temperature range 25–60 °C. The enhanced moisture and solute diffusivity in ultrasound pre-treated kiwi slices was due to cell disruption and formation of microscopic channels.

Osmotic dehydration of bottle gourd (Legeneria siceraria)

Osmotic dehydration of fruits and vegetables an effective method for preservation. The Bottle gourd (Legeneria siceraria) belongs to Cucurbitaceous family. Average composition of fresh bottle gourd is constituted by water (96.0%), carbohydrates (2.5%), fibre (0.6%), proteins (0.2%) and calcium (20mg). The bottle gourd is a common vegetable in India subcontinental. It is moderately perishable vegetable. In this report, efforts were made to analyze the effect of different concentration, temperature and mass ratio of fruit to osmotic solution on osmotic dehydration process of bottle gourd cubes. comparative study for different parameters variables (solid gain weight reduction, water loss) was also studies. Five concentration levels of salt solution were 5, 10, 15, 20, and 25% (w/w) used in this study to compare the effect of the concentration of the osmotic agents on osmotic dehydration. Bottle gourd cubes were immersed in the osmotic reagents with a fruit to osmotic solution mass ratio of 10:1, 20:1 and 30:1 soaking experiment were conducted at 40, 50 and 600C in a 500 mi capacity water bath. The osmotic dehydration was done for a period of 1, 3, 5, 7 and 9 h and replicated thrice. Quality analysis of osmotically dehydrated bottle gourd cubes was done according to ISI (1971) and Ranganna (1991) with 9-point hedonic scale. The moisture content of bottle gourd cubes observed decreases with higher concentration, temperature and mass ratio. The weight reduction, water loss and solid gain were very fast during initial period of osmosis but equilibrium did reach even after 9h. The solid gain, water loss and weight reduction were observed higher for higher temperature, concentration and mass ratio of bottle gourd cubes. The sensory evaluation performed for the approximately central conditions processing parameters gave average scores of 7 or above.

Deshidratador solar híbrido para el secado de plátano

In this work the design of a solar dryer for the dehydration of fruits is presented. Banana is used as raw material for analysis and evaluation purposes. The system is supplied with solar energy in the form of (photovoltaic) PV and (photothermic) PT. The PV part of the dehydrator consists of a solar panel, whose energy supplies electrical resistances to increase the temperature, also feeding a forced air convection system which is carried out with a pair of fans that are at the entrance and exit of the dehydrator, also a control and measurement system. In the other side the PT part consist in a passive storage system of heat direct and indirect catchment of radiation. For the development of the solar dryer it is necessary to take into account certain parameters such as: weather conditions (solar radiation, ambient temperature and wind speed), thermal conductivity, temperature and properties of the components.

Effect of Intermittent Microwave Volumetric Heating on Dehydration, Energy Consumption, Antioxidant Substances, and Sensory Qualities of Litchi Fruit during Vacuum Drying

To examine the processing characteristics and high quality of an improved microwave vacuum drying system, litchi fruits were dried using intermittent microwave volumetric heating while microwave vacuum drying at 2 W/g was carried out for comparison; the intermittent microwave heating profiles were set as (1) 5 min drying-on, 5 min drying-off; (2) 5 min drying-on, 10 min drying-off; and (3) 5 min drying-on, 15 min drying-off. Energy consumption during drying was determined, and physicochemical properties such as moisture content, vitamin C, total phenolics, color, and sensory evaluation of dried products were assessed. In microwave vacuum drying, intermittent microwave volumetric heating was found to be energy-efficient (about 32 KJ/g to 45 KJ/g) and saved at least 31% of energy consumption compared with microwave vacuum drying as well as decreasing product browning. In addition, microwave volumetric heating had no substantial effects on sugar and protein contents, while antioxidants were affected significantly (p ≤ 0.05). Moreover, sensory evaluation showed that intermittent microwave-assisted vacuum drying (IMVD) increased the acceptance of the dried product compared with microwave vacuum drying (MVD).

Low temperature upregulates cwp expression and modifies alternative splicing patterns, increasing the severity of cwp-induced tomato fruit cuticular microfissures

The cwp (cuticular water permeability) gene controls the development of cuticular microfissuring and subsequent fruit dehydration in tomato. The gene underwent silencing in the evolution of the fleshy cultivated tomato but is expressed in the primitive wild tomato relatives. The introgression of the expressed allele from the wild S. habrochaites (cwph) into the cultivated tomato (Solanum lycopersicum) leads to the phenotype of fruit water loss during and following ripening. In this report, we show that low temperature impacts on the severity of the cuticular microfissure phenotype via a combination of effects on both expression and alternative splicing of cwph. The cwp gene, comprising four exons and three introns, undergoes post-transcriptional alternative splicing processes, leading to seven alternative transcripts that differ in reading-frame lengths. Transgenic plants expressing each of the alternative transcripts identified the longest reading frame (VAR1) as the functional splice variant. Low temperature led to a strong upregulation of cwph expression, compounded by an increase in the relative proportion of the functional VAR1 transcript, leading to increased severity of microfissuring of the cuticle. In summary, we demonstrate the molecular mechanism behind the horticultural phenomenon of the low-temperature effect on cuticular microfissures in the dehydrating tomato.

Effect of Refractance Window on dehydration of osmotically pretreated apple slices: Color and texture evaluation

AbstractThe objective of this research was to explore the advantages of apple slices dehydration (cv. Granny Smith) using a Refractance Window (RW) with and without osmotic dehydration as pretreatment and compared with conventional hot‐air drying considering the quality attributes such as color and texture. For pretreatment, the apple slices were osmotically dehydrated and coupled to a moderate electric field (9.3 V/cm) using a sucrose solution (45°Brix) at 40°C until an Aw = 0.95 was achieved. Then, apple slices (with and without pretreatment) were dehydrated using RW at 55, 75, and 95°C and compared with conventional hot‐air drying at 55°C as a control. The results showed that with dehydration using RW, both with and without pretreatment at 95°C, it was possible to achieve a similar quality of apple slices when compared with conventional hot‐air drying at 55°C, but with a significant reduction in processing time. Additionally, the dehydration process using RW presented anomalous diffusion behavior on apple slices with an α > 1.Practical applicationsRefractance Window (RW) is a technology used for dehydration of fruit and vegetables slices and pulp based on the refractance properties of wet materials. RW has reported promising results in processing time reduction as compared with conventional dehydration methods. In addition, the quality of the end products by RW is higher as compared with conventional drying methods. In this research, we have showed that the final product (dehydrated apple slices) using RW attained quality values (color and texture) similar to those obtained with osmotic dehydration (OD) coupled with moderate electric field (MEF)/hot‐air drying. However, the time spent by RW (50 min) was much lower than OD coupled with MEF/hot‐air drying (240 min). Then, the main advantage of RW is the capacity to dehydrate fruit and vegetables materials using temperatures around 100°C, which allow both, reduce processing time and also attain high‐quality retention.