Potato Cubes Research Articles

Machine learning, mathematical modeling and 4E (energy, exergy, environmental, and economic) analysis of an indirect solar dryer for drying sweet potato

A developed indirect solar dryer is built and operated to dry sweet potato cubes. Since, numerous instruments have gathered experimental data to comprehensively evaluate the system's energy, exergy, environmental, and economical aspects. Additionally, four machine learning algorithms, namely Decision Trees (DT), Gradient Boosting Regression (GBR), Multiple Linear Regression (MLR), and Random Forest (RF), are evolved to forecast the solar collector's energy (RSAH,η) and exergy efficiency (RSAH,ηEX) as well as the drying chamber's mean drying temperature and exergy efficiency (DC,ηEx). In addition, ten drying kinetics mathematical models were employed to fit with sweet potato moisture ratio variation over the experiment. Also, Color and bioactive compounds were analyzed. Results show that, RSAH,η and RSAH,ηEX was 72.9 %, and 5.6 %, respectively. Storage unit thermal (ηTh.,SUPCM)and exergy efficiency (ηEx,SUPCM) were 43.4 %, and 18.4 %, respectively, the discharging lasted around 5.5 h. Theoretical drying chamber thermal efficiency (DC,ηth) was from 21.9 to 97.2 %. And av. DC,ηEx was 46.1 %. RF algorithm achieved the best results for RSAH,η, RSAH,ηEX , DC,Tmean, and DC,ηEx forecasting, because of its superior adaptability and generalization. The overall dryer efficiency was 15 % with a specific energy consumption of 4.509 kWh/kg moisture. The Page model showed the best fitting with sweet potato moisture ratio data. In addition, CO2 mitigation reached 20.2 with earned carbon credit is 56771 RMB. The economic payback period is 29.24 months, the annual total revenue is 8464 RMB and 0.7 RMB as a Return on investment.

Potato cubes for the elderly with dysphagia designed through freeze-thaw impregnation technique: Effect of enzymatic hydrolysis

This study aimed to evaluate the effects of enzymatic hydrolysis on the chewing and swallowing properties of potato cubes using a freeze-thaw impregnation technique. The texture properties, microstructure, rheological properties, and suitability as a dysphagia diet of the potato cubes after enzymatic hydrolysis were studied. The results indicated that pectinase reduced the texture of the potato cubes more than cellulase and α-amylase. Pectinase hydrolysis could improve the safety of potato cubes as food for the elderly. Pectinase improved the stability of the mashed potatoes by increasing their viscosity and elastic modulus after chewing, thus improving their swallowing properties. The concentration at 200 U/mL and the hydrolysis time at 60 min were the best hydrolysis condition for pectinase to make dysphagia-suitable potato cubes. This study provides insights into the development of potato-based foods that can be used as dysphagia diet for the elderly.

Potato processing: phenomenology and influence of vibration on bed movement

The configuration of the vibro-spouted bed dryer resembles that of a conventional spouted bed, but the circulation of the particles is controlled by a vertical imposed. As consequence, all the bed flows in a dense phase regime and the air velocity inside the bed is defined according to drying requirements alone. A dryer used in this study consists of a cylindrical chamber with a conical bottom (diameter 145 mm, height 390 mm) equipped with a perforated mobile base, which vibrated at a defined amplitude and frequency. Potato cubes consisting of 5 and 10 mm edges were dried and the behavior of the particles during drying was phenomenologically studied. Shrinkage of potato cubes during drying adequately fit the uniform drying model up to a moisture content of 0.9 kg water/kg dry potato. During the drying of cubes with 5 and 10 mm edges, cracks appear on the faces of the cubes. Fornell's modified model, denoted a good fit to the experimental points, and allowed the generation of characteristic drying curves both at the vary the temperature as the speed of the drying air, useful for computational modeling.

Comparison between vacuum and modified-atmosphere packaging on dynamic analysis of flavor properties and microbial communities in fresh-cut potatoes (Solanum tuberosum L.)

Fresh-cut potatoes are prone to browning and quality deterioration during storage, which leads to a short shelf life. In the present study, we investigated the sensory quality attributes, flavor profiles, and bacterial community composition of fresh-cut potato cubes stored at 4 °C for 18 days in vacuum packaging and 30 % CO2/70 % N2 modified-atmosphere packaging. In addition, a correlation analysis of volatile organic compounds and bacterial taxa was performed. In total, 26 types of volatile organic compounds were identified; aldehydes were considered as the main contributors to the odor, and the off-flavor was mainly described as a mixture of oily, spicy, and beany flavors. The dominant bacteria in all packaged potatoes were fermentative gram-negative bacteria Alcaligenaceae and Sphaerotilus. Notably, compared with vacuum packaging, modified-atmosphere packaging inhibited the generation and development of undesirable flavors and maintained the sensory profile of fresh-cut potatoes in a better manner during storage.

Analysis of exergetic performance for a combined ultrasonic power/convective hot air dryer

Recently, the effectiveness of combined use of non-thermal technologies to improve hot air dryers’ performance from both the energy and quality point of views has been proven. However, no study has been reported on thermodynamic analysis of such hybrid systems. The present work dealt the influence of ultrasonic power combination with convective hot air dryer on exergetic performance of the system. Potato cubes were dried at different drying air temperatures (45–65 °C) and velocities (0.5–1.5 m/s) and ultrasonic powers (0–0.08 kW). Based on the findings obtained through the experiments, the exergy loss varied averagely from 240.58 to 600.83 kJ, and was decreased continuously with increasing the power level. The average exergy destruction ranged from 169.61 to 1554.23 kJ, and was decreased at the higher air temperatures and velocities. Combination of ultrasonic power with hot air intensified the exergy destruction. The average exergy efficiency varied from 24.19 to 91.42% and from 11.67 to 38.27% for the drying chamber and process, respectively.

Generating slow digestibility in cooked potatoes by modulating starch accessibility to α-amylase and mucosal α-glucosidase to different levels

Health issues associated with overconsuming rapidly digestible glycemic carbohydrates continue to be prevalent globally. Transforming starch digestion from a hyperglycemic response to a sustained dietary glucose profile is an ideal digestion scenario. Digesting starch to glucose requires α-amylase (AMY) and mucosal α-glucosidase (m-AG). AMY can quickly break down starch molecules, and m-AG functions as the gatekeeper of dietary glucose production. In this study of cooked potatoes, we hypothesize that slow glucogenesis from starch can be achieved by modulating the accessibility of AMY and m-AG to starch to different levels by modifying cell wall permeability by promoting cross-linking of calcium with endogenous pectins. Raw potato cubes were blanched with 0–500 mg/L calcium solution, followed by steaming. Fully cooked potatoes with the pre-treatment had up to 41% and 99% reduction of the permeability for dextran probes of 20 kDa and 70 kDa, respectively, and a non-detectable permeability of 150 kDa dextran. Permeability data indicated a decrease in the accessibility of AMY and a complete restriction of m-AG to access starch in cells supported by data on starch susceptibility to both AMY and m-AG separately. In vitro stimulated gastrointestinal digestion data demonstrated a blunt glucose profile with a reduction of RDS from 80% to 46% and an increase of SDS from 12% to 37%. By modulating starch accessibility to AMY and m-AG to different extents, cooked potatoes were fully digested with a slow glucose-released profile. The modification was a pre-treatment, and modified potatoes can be processed into potato foods, such as french fries, mashed potatoes, and others.

Bicarbonates and carbonates as antioxidants in vegetable oils at frying temperatures

Antioxidant activity of bicarbonates and carbonates including NaHCO3 , Na2 CO3 , KHCO3 , and K2 CO3 was evaluated in soybean oil (SBO) at 180°C. KHCO3 and K2 CO3 had stronger activity than NaHCO3 and Na2 CO3 . KHCO3 (5.5mEq/L, 0.060wt.%) and K2 CO3 (5.5mEq/L, 0.041wt.%) were more effective than 0.02wt.% tert-butylhydroquinone (TBHQ) in preventing oxidation of SBO. While the antioxidant activity of KHCO3 and K2 CO3 increased with increasing their concentrations up to 5.5mEq/L, it decreased at 11mEq/L. KHCO3 and K2 CO3 were also effective in preventing oxidation of other vegetable oils including avocado, canola, corn, high oleic soybean, and olive oils. Correlation tests conducted with the results from the six oils showed that KHCO3 and K2 CO3 had weak to moderate positive correlations with γ- and δ-tocopherols. In a separate study in stripped SBO, it was found that KHCO3 had a synergistic effect with α-tocopherol, but not with γ- and δ-tocopherols. KHCO3 had additive or synergistic effect with rosemary extract, epigallocatechin gallate, ascorbic acid, and ascorbyl palmitate. Antioxidant activity of KHCO3 was confirmed in frying of potato cubes in SBO and canola oil. Although more studies should be conducted for better understanding of the mechanisms and factors affecting the antioxidant activity of bicarbonates and carbonates, this study demonstrated that they could serve as antioxidants or co-antioxidants of other antioxidants in frying. PRACTICAL APPLICATION: Inorganic salts including NaHCO3 , KHCO3 , Na2 CO3 , and K2 CO3 hadstrong antioxidant activity in vegetable oils at frying temperatures when they wereadded as powder. Antioxidant activity of 0.06 wt.% KHCO3 was higherthan that of 0.02 wt.% TBHQ in soybean oil and canola oil during frying potato. KHCO3 had additive orsynergistic effect with rosemary extract, epigallocatechin gallate, ascorbicacid, and ascorbyl palmitate indicating that these inorganic salts can be usedas co-antioxidants to enhance the antioxidant activity of existing antioxidantswhile they can be used alone as well.

Radio Frequency Drying Behavior in Porous Media: A Case Study of Potato Cube with Computer Modeling

To study the mechanism of heat and mass transfer in porous food material and explore its coupling effect in radio frequency (RF) drying processes, experiments were conducted with potato cubes subjected to RF drying. COMSOL Multiphysics® package was used to establish a numerical model to simulate the heat and mass transfer process in the potato cube and solved with finite element method. Temperature history at the sample center and the heating pattern after drying was validated with experiment in a 27.12 MHz RF heating system. Results showed the simulation results were in agreement with experiments. Furthermore, the temperature distribution and water vapor concentration distribution were correspondent with water distribution in the sample after RF drying. The water concentration within the food volume was non-uniform with a higher water concentration than the corner, the maximum difference of which was 0.03 g·cm−3. The distribution of water vapor concentration in the sample was similar to that of water content distribution since a pressure gradient from center to corner allowed the mass transfer from the sample to the surrounding in the drying process. In general, the moisture distribution in the sample affected the temperature and water vapor concentration distribution since the dielectric properties of the sample were mainly dependent on its moisture content during a drying process. This study reveals the mechanism of RF drying of porous media and provides an effective approach for analyzing and optimizing the RF drying process.

Evaluation of the uniformity, quality and energy cost of four types of vegetables and fruits after pilot-scale pulse-spouted bed microwave (915 MHz) freeze-drying

The homogeneity of dried products produced via pilot-scale pulse-spouted bed microwave (915 MHz) freeze-drying (pilot-scale PSBMFD) was investigated using sweet corn, potato, banana and hawthorn as experimental materials. The quality and energy cost of the dried products were also investigated. Regarding the moisture content, color difference and shrinkage ratio, pilot-scale PSBMFD achieved high drying uniformity (⩾90%, d.b.). Compared with the conventional freeze-drying (CFD) method used in industries, pilot-scale PSBMFD effectively increased the nutrient retention (d.b.) in dried samples. It increased the retention of flavonoids in sweet corn, potato cube, banana slice and hawthorn by approximately 11.68%, 15.82%, 5.76%, and 15.94% and the total phenolic content by 11.85%, 23.58%, 28.34%, and 24.17%, respectively. Further, pilot-scale PSBMFD resulted in a larger honeycomb porous structure, greater hardness and brittleness as well as shrinkage and lower apparent density than CFD. Regarding the energy cost, pilot-scale PSBMFD can save more energy than CFD (⩾39%, d.b.). This pilot-scale experimental study provides a theoretical basis and technical support for the commercial application of the PSBMFD technology.

3D simulation of momentum, heat and mass transfer in potato cubes during intermittent microwave-convective hot air drying

3D simulation of momentum, heat and mass transfer in potato cubes during intermittent microwave-convective hot air drying

Effect of vacuum assisted microwave drying on drying behavior of potato cubes

The present study was focused on effect of microwave powers i.e. 160, 320, 480, 640, and 800 W on dryingcharacteristics of potato cube (1.2 c. m. x 1.2 c. m. x 1.2 c. m.). Microwave drying led to reduction in moisturecontent and drying time reduced with the increase in power level. Increase in power level from 20% to100% led to reduction in drying time approximately of 8 min. The drying rate increased with increasingpower level having a minimum value of 0.043% for 160 W power levels to a maximum value of 0.29% for800 W power levels. Increasing the vacuum level further increased the drying rate for each power level. At160 W power level for 100 mmHg vacuum level the maximum reduction in moisture content was 48.668%dry basis, which was increased to a maximum difference in moisture content of 215.75% dry basis at 300mmHg vacuum level or 800 W power level corresponding to a 1/8 time reduced duration of 2.5 min.

Prediction of diffusion coefficient for losses of minerals from potato during frying

This study assessed the diffusion coefficient (Da) for mineral losses from potatoes during the frying process under various conditions by using the solution to Fick’s second law for a slab of infinite extent in non-dimensionalized form. Diffusion coefficient values increased as potato cube frying temperature increased from 65°C to 95°C in 16 mins. Calcium (Ca) had values ranging between 3.693×10-10 to 3.9872×10-10 M 2 S -1 ; Iron (Fe) ranged between 2.931×10-10 to 3.314×10-10 M 2 S -1 ; Magnesium (Mg) ranged between 5.576×10-10 to 7.666×10-10 M 2 S -1 ; Potassium (K) ranged between 7.841×10-10 to 8.516×10- 10 M 2 S -1 , and Sodium (Na) ranged between 2.823×10-10 to 3.513×10-10 M 2 S -1 . It was found that the effect of temperature on the diffusion coefficient had an Arrhenius-type equation correlation. Activation energy values for Ca, Fe, K, Mg, Na loss in potato were 10.49 kJ/ mol, 8.17 kJ/mol, 12.85 kJ/mol, 11.16 kJ/mol, and 9.98 kJ/mol, respectively. It was found that the diffusion coefficient (Da) values for minerals losses were independent of diameter in the 0.5 to 1.5 cm range. Diffusion coefficients (Da) for Ca were observed as 2.961×10- 10 M 2 S -1 and 2.632×10-10 M 2 S -1 for 1.0 cm and 0.5 cm diameters, respectively, when tested at 75°C for 16 mins. Mg had Da values of 6.722×10-10 M 2 S -1 and 6.891×10-10 M 2 S -1 at 1.0 cm and 0.5 cm, respectively. Potassium had coefficient values of 8.013×10-10 M 2 S -1 and 8.319×10-10 M 2 S -1 at 1.0 cm and 0.5 cm, respectively, at similar testing conditions. Therefore, dimensions do not affect the diffusion coefficient significantly.

Numerical simulation and microtomography study for drying a deformable isodiametric-cellular food

Abstract The aim of this work is the simulation of volumetric strain of tuberous crop during drying. We propose a poroelastic model for predicting the drying kinetics and volume loss of potato cubes during convective drying. The Biot’s theory of poroelasticity was used, which considers the Lamé parameters, Young’s modulus and Poisson’s ratio. Drying kinetics and volumetric strain were modeled and compared versus experimental data. An X-ray microtomograph coupled with image analysis was used to visualize the shape and size of the samples during drying. Drying experiments were conducted at 50, 60 and 70 °C, 20% RH, with an air velocity of 1 and 2 m/s. The drying process was interrupted several times to perform tomographic acquisitions. We found a period of ideal shrinkage, nevertheless, the volumetric strain reveals a kinetic behavior over time. The model computes the volumetric strain, which describes correctly the experimental data obtained by microtomography.

Release Kinetics Studies of Early-Stage Volatile Secondary Oxidation Products of Rapeseed Oil Emitted during the Deep-Frying Process.

The research concerns the use of proton transfer reaction mass spectrometer to track real-time emissions of volatile secondary oxidation products released from rapeseed oil as a result of deep-frying of potato cubes. Therefore, it was possible to observe a sudden increase of volatile organic compound (VOC) emissions caused by immersion of the food, accompanied by a sudden release of steam from a potato cube and a decrease of the oil temperature by more than 20 °C. It was possible to identify and monitor the emission of major secondary oxidation products such as saturated and unsaturated aldehydes, namely acrolein, pentanal, 2-hexenal, hexanal, 2-nonenal and 2-decenal. Each of them has an individual release characteristic. Moreover, the impact of different initial frying temperatures on release kinetics was investigated. Subsequently, it was possible to approximate the cumulative emission by a second-degree polynomial (R2 ≥ 0.994). Using the proposed solution made it possible for the first time to observe the impact of the immersion of food in vegetable oil on the early emission of thermal degradation products oil.

The Influence of the Production Process on the Anthocyanin Content and Composition in Dried Potato Cubes, Chips, and French Fries Made from Red-Fleshed Potatoes

The stability of acylated anthocyanins is still a new and unexplored subject of study. The changes in the contents of individual anthocyanins in colored-flesh potato tubers during processing have rarely been addressed in the literature. The aim of the present study was to determine how anthocyanin degradation and profiles are influenced in potatoes of the red-fleshed Herbie 26 variety by different methods of processing. Potato samples were divided into four categories to be analyzed, namely, raw material, potato cubes, French fries, and chips. The dried cubes, French fries, chips, semi-finished products, and finished products, obtained through laboratory processing, were examined for anthocyanin content and composition. The production process of cubes, chips, and French fries led to losses of the examined anthocyanins; however, these losses differed depending on the technological stage. The greatest losses of these compounds were determined after the final production processes, i.e., pre-frying, frying, and drying. Chip production led to the lowest losses of anthocyanins. Omitting the blanching stage in chip production allowed the retention of more anthocyanins. Pelargonidin-3-feruloylrutinoside-5-glucoside, having the highest percentage in the raw material (approximately 50%), followed by pelargonidin-3-caffeoylrutinoside-5-glucoside, proved to be the most thermally stable.

Advantages of ohmic cooking in the kilohertz range – Part II: Impact on textural changes and approaches to improve heating uniformity

The impact of ohmic heating (OH) in the low (12 kHz) and high (300 kHz) kilohertz-range on textural changes and texture uniformity of potato cubes and whole potato tubers was investigated. Potatoes were heated in aqueous NaCl solution with a conductivity of 2.5 mS/cm. Texture was characterized by cutting and puncture tests and the energy (mJ) necessary to cut or penetrate the samples was found to be a suitable indicator. The impact of the initial temperature of the surrounding liquid on the heating uniformity was analyzed by starting the cooking treatment in cold (20 ± 2 °C) and in hot (90 ± 5 °C) NaCl solution. To further improve the heating efficiency, the conductivity was adjusted during the treatment. With an increasing power input during OH, increasing texture softening rates were observed. Compared to conventional cooking, an up to 8-times faster texture softening rate occurred. Treatments at 300 kHz resulted in a better texture uniformity compared to OH at 12 kHz. Compared to the conventional cooking, OH treatments resulted in significant (p ≤ 0.05) higher weight losses and a higher texture softening at similar cooking degrees. By adjustment of the liquid conductivity and power input during the treatment, textural properties were improved, and weight loss could be reduced. Industrial relevanceOhmic heating (OH) is an alternative heating technology with the potential to reduce processing times and energy consumption. It can overcome limitations in the heat transfer particularly given for large-volume solid foods and provide a uniform heating. However, limited attention has been given to the effects of the product and process parameters on the heating uniformity during OH treatments of solid foods. The present paper highlights the importance of the electrical conductivity and the frequency of the applied electric field on the texture uniformity. The obtained results contribute to the understanding of the interaction of the electric field and the food matrix, which is the basis for the implementation of tailored and targeted processing concepts in the industry.

Advantages of ohmic cooking in the kilohertz-range - part I: Impact of conductivity and frequency on the heating uniformity of potatoes

The heating uniformity of potato cubes and whole potato tubers was investigated during cooking by ohmic heating (OH) in the low (12 kHz) and high (300 kHz) kHz range. Potatoes were heated in aqueous NaCl solutions with various conductivities (1–5 mS/cm). Conductivities and cell disintegration index of the tissue were determined in dependency of the temperature and the frequency at different points in the tubers. Heating uniformity was characterized by analyzing the temperature profiles with up to four thermocouples and by thermal imaging. Heating behavior of peeled and unpeeled tubers were compared to evaluate the impact of the skin on the OH treatment. For the higher frequency applied, increased electrical conductivities in the potato tissue were observed. At 300 kHz a better heating uniformity, with lower temperature differences within the potato samples compared to OH at 12 kHz was observed. The results provide a better understanding of the effect of high frequency electric fields on the heating uniformity and the conductivity of intact potato tissue. Industrial relevanceOhmic heating (OH) is an alternative heating technology with the potential to reduce processing times and energy consumption. It can overcome limitations in the heat transfer particularly given for large-volume solid foods and provide a uniform heating. However, limited attention has been given to the effects of the product and process parameters on the heating uniformity during OH treatments of solid foods. The present paper highlights the importance of the electrical conductivity and the frequency of the applied electric field on the heating uniformity. The obtained results contribute to the understanding of the interaction of the electric field and the food matrix, which is the basis for the implementation of tailored and targeted processing concepts in the industry.

Modeling the Kinetics of Potassium Diffusion in Estima Potato under Different Leaching Conditions.

The diffusion of potassium in potato (Solanum tuberosum) at different leaching conditions was investigated. Two modes of pretreatment of potato samples (cubes and spheres) by preheating to 80°C and leaching at temperatures of 20-80°C were performed using a temperature- and agitation-controlled batch extractor. A Fickian model incorporating the effective diffusion coefficient (Deff), partition coefficient (K) between the solute concentration in the potato and medium, and mass transfer coefficient (kl) was developed to simulate and predict the fraction of potassium leached from the potato at any temperature. Results showed significant reduction in activation energies from 92 to 25.02 kJ/mol for cubes and from 75.02 to 13.40 kJ/mol for spheres culminating in higher extraction rates when samples were preheated to 80°C. The Deff, K, and kl values obtained were in the range of 0.02 − 7.33 × 10−9 m2/s, 0.63 − 8.00 × 10−2, and 0.01333.00 × 10−4 m/s, respectively. The kinetic parameters showed a change in slope or discontinuity in the gelatinization temperature range as a function of temperature, an indication of a change in the diffusional matrix. The optimum operating conditions were 80°C preheating and leaching at temperatures up to 50°C. The proposed mathematical model offered a satisfactory description of both dynamic and equilibrium mass transfers of potassium by adequately predicting the fraction of potassium from potato cubes and spheres. The present findings could be useful in the pretreatment of potato for renal patients.

Effects of different drying methods on drying kinetics, physicochemical properties, microstructure, and energy consumption of potato (Solanum tuberosum L.) cubes

In current work, air impingement drying (AID), infrared-assisted hot air-drying (IR-HAD), and hot air drying based on temperature and humidity control (TH-HAD) drying technologies were employed to drying potato cubes and their effects on drying kinetics, color, ascorbic acid content, rehydration ratio, microstructure, and specific energy consumption (SEC) were explored. Besides, artificial neural network (ANN) was used to predict changes in moisture ratio during the drying process. Results indicated that TH-HAD had the shortest drying time, followed by IR-HAD and AID. The effective moisture diffusivity (Deff ) of potato under TH-HAD, IR-HAD and AID were 1.35 × 10−9, 1.18 × 10−9, and 0.90 × 10−9 m2/s, respectively. TH-HAD contributed to excellent physicochemical properties of dried potato when compared to samples dried by IR-HAD and AID. Overall, TH-HAD provided higher ascorbic acid content, better rehydration ability, brighter color, and had lower specific energy consumption (SEC). The microstructure well explained the difference of rehydration ratio and drying kinetics under different drying methods. The ANN models with the optimal topology could predict the moisture ratio under different drying methods with satisfactory accuracy. The current findings indicate that TH-HAD is a promising drying technology for potato cubes and has the potential to be applied in commercial scale.

Industrial applications of selected JFS articles

Industrial applications of selected <i>JFS</i> articles