Potato Cubes Research Articles

Development of Process Technology for Preparation of Ready-to-eat Puffed Potato Cubes

Potato chips are very popular snack food in India and the French fries are also getting popularity in big cities of the country. But potato chips and French fries both contain high amount of fat 36.8 to 38.1% respectively, which is harmful for human health. Therefore, the need was realized to develop puffed potato cubes that could be used as oil free snack food. The puffing parameters: temperature, time, cube size, and moisture content were studied with respect to volume expansion ratio and non enzymatic browning of the puffed cubes. The best conditions observed were puffing temperature of 150°C, puffing time of 4 min., cube size of 12 mm, and moisture content of 50% w.b. At these conditions, volume expansion ratio of 1.6 and optical density of 0.2 were observed. The freshly puffed cubes were very much liked by the panelists and its acceptance was at par with French fries. A puffing machine was developed to process 5 kg puffed potato cubes per hour.

Comparative fractal characterization of physical changes of different food products during drying

The development of a relationship between microstructural changes of model food products (carrot and potato cubes) and their physical changes during conventional hot air drying (HAD) using combined fractal and image analysis was performed in this study. Dried carrot and potato sections were examined by light microscopy and the fractal dimension (FD) of the microscopic images was determined using a box counting technique. The apparent physical changes of the samples undergoing HAD were represented in terms of the percentage of shrinkage and rehydration ratio. These apparent changes correlated well with their microstructural changes represented by the normalized changes of fractal dimension (ΔFD/FD 0) of the microstructural images. Although the microstructural changes of the samples undergoing HAD were quite different, the changes of ΔFD/FD 0 of the samples undergoing drying were in the same trend. FD has thus proved to be a good indicator of microstructural changes of products undergoing drying.

Modeling Texture Kinetics during Thermal Processing of Potato Products

A kinetic model based on 2 irreversible serial chemical reactions has been proposed to fit experimental data of texture changes during thermal processing of potato products. The model links dimensionless maximum force F*(MAX) with processing time. Experimental texture changes were obtained during frying of French fries and potato chips at different temperatures, while literature data for blanching/cooking of potato cubes have been considered. A satisfactory agreement between experimental and predicted values was observed, with root mean square values (RMSs) in the range of 4.7% to 16.4% for French fries and 16.7% to 29.3% for potato chips. In the case of blanching/cooking, the proposed model gave RMSs in the range of 1.2% to 17.6%, much better than the 6.2% to 44.0% obtained with the traditional 1st-order kinetics. The model is able to predict likewise the transition from softening to hardening of the tissue during frying.

Effect of drying conditions on the quality of vacuum-microwave dried potato cubes

The influence of drying conditions on the color, starch content, sugar content, mechanical properties and microstructure of dried potatoes was studied. Statistically significant differences between the color of raw and dried materials were observed for every drying methods. It was observed that the vacuum-microwave drying technique prevents color damage during drying. Potato cubes dried in a vacuum-microwave oven had lower starch and total sugar losses than those dried under forced convection conditions. The maximum force values obtained from compression tests indicated statistical differences between samples dried in a microwave-vacuum drier and a convection drier. The averaged force and energy required to cause 3 and 5.5 mm deformation were the highest for blanched and hot-air dried (70 °C) potato cubes, and the lowest for vacuum-microwave dried material (24 kPa). The application of microwave energy led to different physical changes in product microstructure, compared to those observed during hot-air drying. The extent of changes was depended on the method and parameters of drying. In both cases the drying process caused deformation and disintegration of cell walls and starch granules. Experiments show that in the case of hot-air drying the intensity of structural changes depends on drying temperature. A higher temperature causes greater damage to the microstructure of potato cubes. Microwave drying at 24 kPa ensured the shortest drying time and the best overall quality of dried potato cubes, and thus was chosen as the most appropriate technique for potato drying.

Effect of low-dose γ-irradiation on the shelf life and quality characteristics of minimally processed potato cubes under modified atmosphere packaging

The processing conditions involving γ-irradiation for minimally processed potato cubes were optimized by response surface methodology. The effect of γ-irradiation dose (0–1.5 kGy), citric acid concentration (0–1.0%), KMS concentration (0–1.0%) and their complex interaction on L, a, b value, hardness and total sugar content were studied using a central composite rotatable design of experiments. The results showed that at the optimum conditions ( γ-irradiation dose 1.0 kGy; citric acid concentration 0.33% and KMS concentration 0.55%) the L-value was ⩾48.50%, a-value ⩽0.95, b-value ⩽7.5, hardness ⩾100 N, sucrose concentration ⩽0.19% and sensory score ⩾6.0 at the end of the storage period of 4 weeks.

Influence of different processing methods on the glycemic index of potato (Nicola)

Potato is a food which yields very variable glycemic responses. It makes a major contribution to total starch intake and the share of processed potato products is growing. The aim of the study was to determine the effects of processing and storage on the glycemic indices (GIs) of industrially processed potato products. Two groups (11 and 10 volunteer subjects) attended a glucose tolerance test and glycemic response test of 4 and 3 processed potato products, respectively. GIs of different potato products were calculated for each subject using their own glucose tolerance test and glycemic responses for test meals and averages calculated for each product. GIs of freshly prepared potato products were high: steam boiled potatoes 104±39, oven-baked casserole 95±30 (carbo-peeled sliced potato) and mashed potatoes 106±42. GIs of cooled and cold stored potato products were intermediate, potato cubes served cold 76±32 and cooled, reheated oven-baked casseroles 73±25 (carbo-peeled sliced potato), 75±17 (carbo-peeled mashed potato) and 81±28 (steam-peeled mashed potato). Cooling and cold storage decreased GIs significantly (steam boiled potatoes vs. steam boiled potato cubes ( P = 0.01 ), freshly served casserole made of sliced potatoes vs. casserole cooled, cold stored and reheated P = 0.01 ). Conclusion Cooking method, peeling method, or slicing or mashing did not affect the GIs. Cooling and cold storage, despite reheating, lowered GIs of potato products by about 25%.

Comparison of Water Blanching and High Hydrostatic Pressure Effects on Drying Kinetics and Quality of Potato

Drying kinetics and quality parameters of potato cubes were evaluated as affected by high pressure processing and hot water blanching. The potato cubes in 1% citric acid solution as immersion medium were pressure treated at 400 MPa for 15 min. Hot water blanching was conducted in boiling water for 3 min. Drying kinetics and quality parameters (i.e., rehydrability, texture, color and apparent density) were assessed for the high pressure–treated and water-blanched samples and for dehydrated and rehydrated samples. Drying rates were found to be higher (p < 0.05) in the initial period of drying for the pressure treated samples. The Page model was found to better fit drying data of the thermally treated samples, and the two-terms model better described the drying behavior of high pressure–treated samples. High pressure–treated samples had a similar rehydrability to thermally treated samples. It was found that pressure–treated samples had a hardness value close to that of fresh samples, whereas thermal treatment resulted in a softer texture. After rehydration, samples of both treatments returned their texture before drying. The total color difference for the thermally blanched samples was higher (p < 0.05) than for pressure–treated samples before drying and after drying. High pressure–treated and dried potato cubes had a color close to that of fresh potato cubes. High pressure–treated and air-dried samples were found to have higher (p < 0.05) apparent density than thermally treated samples.

Whirling bed blanching of potato cubes and its effects on product quality

A new technique of modified fluidized bed called whirling bed was adopted for blanching of potato cubes as the large particles (>4 mm) cannot be effectively fluidized by conventional fluidized bed as well as by spouted bed. Whirling bed blanching was accomplished by passing a saturated mixture of hot air and steam through a cylindrical column fitted with a semicylindrical wedge at its base on distributor plate for partial air restriction. The blanched product quality was compared with that obtained by hot water and steam blanching in terms of enzyme inactivation, solid loss, moisture content and retention of nutrients like ascorbic acid and reducing sugar. Rate of loss and diffusivities of ascorbic acid and reducing sugar were also studied. It was observed that whirling bed blanching (at 85 °C) required less time and resulted in higher retention of solids and nutrients as compared to hot water and steam blanching.

Modified test for potato sloughing assessment

Direct methods for potato sloughing assessment mostly consist in CPM (cooked potato mass) tests in which potato cubes are cooked, sieved and the mass of the remaining cooked potato tissue on the sieve is recorded. The characteristic time CT100 determined from the CPM cooking curve indicates the potato resistance to sloughing. The CPEM (cooked potato effective mass) method was proposed as a modification of the CPM tests. The potato mass is determined continually during cooking so that the whole cooking curve is obtained in one test. The CPEM cooking curve has two main parts (the cooking and the breaking part) from which two CPEM parameters: cooking time (CT) and slope of the breaking part (SBP) characterising the disintegration process are derived. Two potato varieties Agria and Samantana cultivated under different conditions were tested. Dependence of the CPEM parameters on the potato tuber density was observed. The CPEM parameters differed more for different cultivation conditions than for different varieties.

A study of the mass transfer in osmotic dehydration of coated potato cubes

This study investigated the coupling of edible coatings with osmotic dehydration of potato cubes under various process conditions. Solutions of 1% sodium alginate and 2% low methoxyl pectinate (LMP, degree of esterification: 31.5%) were chosen as the coating materials and NaCl was used as the osmotic agent to study the mass transfer behavior during osmotic dehydration of potato tissues. Potatoes were cut into cubes of 1 cm 3 and coated with the coating materials. Calcium chloride solution of 1% or 2% was used as the cross-linking agent. Salt concentration of 10%, 14% and 18% and temperature of 25, 40 and 55 °C were used as the process variables to investigate the kinetics of water loss and salt uptake. Modeling of the mass diffusion and its kinetics were carried out to better understand the mass transport phenomena in potatoes with coatings and to determine the efficacy of the coupled system. Mass transfer kinetics was modeled by using Peleg’s proposed equation and the effect of process variables on the model parameters was studied. Diffusivities of both water and solute were evaluated by using Crank’s analytical solution to Fick’s second law. These two models could well describe how the considered variables influenced the mass diffusion and kinetic rate constants during the osmotic dehydration of both non-coated and coated potatoes.

Kinetic modelling of texture development in potato cubes ( Solanum tuberosum L.), green gram whole ( Vigna radiate L.) and red gram splits ( Cajanus cajan L.)

Texture is one of the most important quality parameter, which influences the acceptability of food products. The kinetics of texture development which was evaluated using a Stevens-LFRA Texture Analyzer in terms load in grams, has been studied over a temperature range of 50–120 °C (isothermal process), and also during normal open pan cooking, pressure-cooking and a cooking in a newly developed and patented fuel-efficient ‘EcoCooker’ (non-isothermal heating process). The texture development followed first order kinetics in potato cubes, whole green gram and red gram splits, the food samples used in this study. A mathematical model was developed using the rate constants of texture development at fixed temperatures and the time–temperature profile of the processing method.

Continuous flow radio frequency heating of particulate foods

Small whole carrots, carrot cubes, and potato cubes suspended in 1% (w/w) CMC solutions were heated by a 40.68-MHz, 30-kW continuous flow radio frequency (RF) unit that has an applicator tube with an inner diameter of 14.6 cm (5.75 in.) and a height of 2.1 m (82.5 in.). Solution temperatures and the residence time when the particles entered and left the system were recorded. An infrared camera was used to record the temperature distribution within the particulates. A relatively nonuniform temperature distribution (a local difference up to 8 °C) was seen within carrot cubes (2 cm each side). However, the temperature distributions within small whole carrots and potato cubes (2 cm each side) were relatively uniform (a local difference of 1 to 4 °C). The structure at the center of the big carrot used to make carrot cubes may result in different dielectric properties from the rest of carrot and therefore slower heating at these areas. Although the initial temperature inside the particles (∼7 °C) was significantly lower than that of the solution, the exit temperatures (averages ranging from 38 to 60 °C) within the particles were close to the solution temperatures. Uniform temperature distribution within the particles makes RF a promising heating source in thermal processing, especially aseptic processing of liquid and particulate foods.

Combined treatments of blanching and dehydration: study on potato cubes

Samples of Solanum tuberosum var. Primura were submitted to combined treatments of blanching and dehydration. Blanching was alternatively performed in hot distilled water, hot sugary-saline solution, by microwaves in distilled water or by microwaves in saline solution. Drying was alternatively carried out in an air cabinet, a microwave oven or a belt drier. In terms of process speed, colour retention and water absorption capacity, the best results were obtained combining microwave blanching with dehydration on the belt drier. In particular, dehydration on the belt drier levelled eventual negative effects determined by the blanching treatments.

Optimisation of high temperature puffing of potato cubes using response surface methodology

One cubic centimetre potato cubes were blanched, sulfited, dried initially for between 40 and 80 min in air at 90 °C in a cabinet drier, puffed in a high temperature fluidised bed and then dried for up to 180 min in a cabinet drier. The final moisture content was 0.05 dwb. The resulting product was optimised using response surface methodology, in terms of volume and colour ( L*, a* and b* values) of the dry product, as well as rehydration ratio and texture of the rehydrated product. The operating conditions resulting in the optimised product were found to be blanching for 6 min in water at 100 °C, dipping in 400 ppm sodium metabisulfite solution for 10 min, initially drying for 40 min and puffing in air at 200 °C for 40 s, followed by final drying to a moisture content of 0.05 dwb.

The effect of ohmic heating on vacuum drying rate of sweet potato tissue.

Ohmically heating fruit and vegetable tissue has been shown to increase hot-air drying rate, shift desorption isotherms, and increase juice extraction yields with respect to untreated, conventionally heated, and microwaved samples. The objective of this study was to determine if ohmically heating sweet potato tissue would enhance the vacuum drying rate of these samples with respect to untreated samples. Sweet potato cubes were ohmically heated to three endpoint temperatures using three electrical field strengths and were then placed in a freeze dryer. Moisture content vs. time data were collected and modeled. Results showed that the vacuum drying rates of ohmically heated samples were faster than raw samples for most treatment combinations, and that the maximum reduction of drying time was 24%. Minimal ohmic treatment can result in a significant decrease in vacuum drying time, which could have important economic and product quality implications.

Mechanical Damage to Food Particles During Processing in a Scraped Surface Heat Exchanger

The influence of processing conditions on particle damage in a commercial-scale scraped surface heat exchanger (SSHE) was studied using a model system of potato cubes in carboxymethyl cellulose solution. In order to separate thermal degradation effects from mechanical damage, the potato cubes were pre-cooked, for a controlled time, before being passed through the SSHE isothermally. Particle attrition occurred within the SSHE and was found to lead to a severe reduction in the size of soft particles (e.g. following a long cooking period). Experimental evidence suggested that the particle damage was due primarily to particle-blade collisions. Two processing variables were found to have a direct bearing on the degree of particle attrition: the rotor speed, which determined the collision frequency, and the mean particle residence time, which governed the total number of collisions experienced per particle. An increase in the fluid viscosity reduced particle attrition by decreasing the mean particle residence time rather than offering any protective effect per se. Selection of the appropriate operating conditions for particle processing in a SSHE should take account of mechanical damage as well as thermal treatment considerations. Least damage to a soft particle will occur with a low rotor speed and a low particle residence time. The latter may be achieved by an increase in the viscosity of the carrier medium.

A response surface methodology approach to optimise pretreatments to prevent enzymatic browning in potato (Solanum tuberosum L) cubes

AbstractThe objective of this work was to find the best combinations of ascorbic acid concentration/soaking time (Pretreatment 1), 4‐hexylresorcinol concentration/soaking time (Pretreatment 2) and ascorbic acid concentration–4‐hexylresorcinol concentration/soaking time (Pretreatment 3) to prevent the development of enzymatic browning in raw potato cubes (10 mm × 10 mm × 10 mm). Potato variety Alpha was used as study model because of its low susceptibility to enzymatic browning. Response surface methodology was applied in all pretreatments on two response variables (Hunter L value and total colour difference) to find the best conditions for carrying out the pretreatments. The various pretreatments had variation levels for ascorbic acid (AA) concentration (1 and 3) and 4‐hexylresorcinol (4HR) concentration (2 and 3) of 1–4 and 0.04–0.20 g l−1 respectively; in all pretreatments the variation level for soaking time was 3–6 h. A central composite experimental design with two factors at five levels was used. Predictive models for Hunter L value and total colour difference were developed as a function of process or independent variables. The optimisation technique was applied to obtain maximum Hunter L values and minimum values of total colour difference. Surface superposition of these variables allowed identification of the best combinations of process variables for each pretreatment as (1) 2.9 g l−1 AA/4.8 h, (2) 0.04 g l−1 4HR/2.6 h and (3) 2.42 g l−1 AA–0.15 g l−1 4HR/5.41 h.© 2001 Society of Chemical Industry

OSMOTIC DEHYDRATION OF POTATO: EQUILIBRIUM KINETICS

Osmotic dehydration kinetics of potato slices and cubes was studied using sugar syrup of different concentrations and temperatures. The initial concentration of sucrose was varied from 30 to 65%, and temperature was varied from 22 to 80°C. The equilibrium coefficients for solids ranged from 0.84 to 1.55, and for water it ranged from 0.70 to 1.05. The equilibrium coefficient for solids increased with the increase in temperature while it decreased with the increase in syrup concentration. However, the equilibrium coefficient for water decreased with increasing temperature and it increased with the increase in syrup concentration. A multiple regression analysis of experimental data was carried out to correlate equilibrium coefficients with dimensionless temperature and syrup concentration.

A Technique to Measure Firmness in Potato Tissue during Frying

The suitability of a cylinder fabricated from stainless steel was investigated for measuring the textural changes in potato during frying. The cylinder was attached to a TA.XT2 texture analyzer. A circulating heating bath was suitably connected to the cylinder. Initially, sunflower oil in the heating bath was brought to 180 'C without allowing it to circulate into the cylinder. A cube of potato tissue was positioned at the center of the cylinder with the help of a metal plate. The metal plate also allowed a thermocouple to be inserted into a potato cube to measure sample temperatures. The texture analyzer was then set to cause a continuous 20% strain. Heated sunflower oil from the bath was then circulated into the cylinder, thereby achieving complete immersion of potato tissue during force measurements. The circulating heated oil rapidly raised the tissue temperature from 20 'C to about 85 0C in 30 s, and, thereafter, a slow increase was observed. Firmness, expressed as the force required to cause 20% strain in the cube of potato tissue, slightly decreased during initial frying followed by a rapid decline. In separate hot-stage microscopy experiments, temperatures corresponding to swelling of starch granules and cell disruption were examined and compared with the firmness data. The stainless steel cylinder certainly allowed continuous circulation of heated oil and also kept the food sample in direct contact with oil during force measurements. This technique has limitations if absolute values of firmness are required. However, for zomparing texture profiles of different food samples during frying, the technique allows continuous measurements to be made.

A Technique to Measure Firmness in Potato Tissue during Frying

The suitability of a cylinder fabricated from stainless steel was investigated for measuring the textural changes in potato during frying. The cylinder was attached to a TA.XT2 texture analyzer. A circulating heating bath was suitably connected to the cylinder. Initially, sunflower oil in the heating bath was brought to 180 'C without allowing it to circulate into the cylinder. A cube of potato tissue was positioned at the center of the cylinder with the help of a metal plate. The metal plate also allowed a thermocouple to be inserted into a potato cube to measure sample temperatures. The texture analyzer was then set to cause a continuous 20% strain. Heated sunflower oil from the bath was then circulated into the cylinder, thereby achieving complete immersion of potato tissue during force measurements. The circulating heated oil rapidly raised the tissue temperature from 20 'C to about 85 0C in 30 s, and, thereafter, a slow increase was observed. Firmness, expressed as the force required to cause 20% strain in the cube of potato tissue, slightly decreased during initial frying followed by a rapid decline. In separate hot-stage microscopy experiments, temperatures corresponding to swelling of starch granules and cell disruption were examined and compared with the firmness data. The stainless steel cylinder certainly allowed continuous circulation of heated oil and also kept the food sample in direct contact with oil during force measurements. This technique has limitations if absolute values of firmness are required. However, for zomparing texture profiles of different food samples during frying, the technique allows continuous measurements to be made.