Potato Cubes Research Articles

Effect of thermal shock cycling on storage stability and quality of fresh-cut potato

To enhance the storage stability and quality of fresh-cut potato, potato cubes with dimensions of 1 × 1 × 1 cm3, 2 × 2 × 2 cm3, and 3 × 3 × 3 cm3 were blanched at 90 °C for 15, 30, or 45 s, followed by soaking in ice-water for 1 min; the treatment was repeated for up to six cycles. The 2 × 2 × 2 cm3 and 3 × 3 × 3 cm3 potato cubes subjected to six thermal shock cycles for cycling times of 30 s and 45 s showed significant lowering of the browning index during storage at ambient temperature. The 1 × 1 × 1 cm3 potato cube was most highly susceptible to browning, although repeated thermal shock cycling reduced the development of browning. A higher number of thermal shock cycles effectively decreased the polyphenol oxidase (PPO) activity of the potato cubes. The reduction of the PPO activity was more pronounced as the sample size decreased. The hardness of the raw and fried samples decreased, along with reduction of the melting enthalpy, as the treatment time and number of cycles increased. The browning index of the fried potato declined as the number of cycles increased.

Effect of methyl jasmonate on wound healing and resistance in fresh-cut potato cubes

The aim of this study was to investigate the effects of methyl jasmonate (MeJA) treatment on physiology and quality attributes of fresh-cut potato cubes during storage. The fresh-cut potato cubes treated with MeJA showed occurrence of enzymatic browning, with higher total phenol and flavonoid content than the control cubes during 144 h of storage at room temperature (23 ± 1 °C). The activity of polyphenol oxidase (PPO), peroxidase (POD) and catalase (CAT) in fresh-cut potato cubes have also been increased significantly by MeJA treatment. MeJA induced an increase of activity in phenylalnine ammonialyase (PAL), cinnamate-4-hydroxylase (C4H) and 4-coumarate-CoA ligase (4CL) of fresh-cut potato cubes, compared to the control. RT-qPCR showed that the gene expression of PAL, C4H, 4CL, PPO, POD and CAT was significantly higher in MeJA-treated cube parenchyma tissues than that in control. Our experiments also showed that MeJA treatment could maintain firmness but enhanced the browning of the fresh-cut cubes. In addition, the parenchyma tissues of MeJA-treated fresh-cut cubes also showed higher suberin polyphenolic (SPP) and thicker cell wall than that in the control.

Study on the convective drying of potato cube

Drying is a conventional method of food preservation that removes sufficient number of moistures from the food so bacteria, yeast and molds cannot grow. There are several drying techniques can be found in industry such as convective drying and freeze drying. In this study a potato cube is taken into consideration of convective drying experimentally. A small-scale wind tunnel has been designed and fabricated. During experiment, the temperature and mass of the potato cube are measured and recorded. Temperature and velocity of the hot drying air are measured. In order to provide a better analysis computational fluid dynamic is also carried out. The heat and mass transfer analysis during the drying are presented. The results show that the average drying rate of the potato cube is 4.061 gr/hour. The present results can be used to support the necessary information on developing high efficient artificial drier.

EFFECT OF THE PRODUCTION PROCESS ON THE CONTENT OF ANTHOCYANINS IN DRIED RED-FLESHED POTATO CUBES

This study aimed at determining the effect of particular stages in the laboratory manufacture of dehydrated potato cubes on the stability of anthocyanin content in red-fleshed potato varieties. The raw material used in the study was potatoes of the following three red-fleshed varieties: Rosemarie, Herbie 26, and Rote Emma. The analysed potato varieties differed in their respective content of anthocyanins and polyphenols. A higher content of these compounds was found in potatoes of Rote Emma cv. (216 mg/100 dm polyphenols and 37.3 mg/100 g anthocyanins). The greatest losses of anthocyanins were noted after peeling and pre-drying and those of total polyphenols were noticed after blanching, pre-drying and drying. In comparison to the raw material, only ca. 25% of anthocyanins and ca. 31% of total polyphenols remained in the finished product. Among the analysed varieties, Rote Emma might be recommended for the production of dried potato cubes. This is because the highest content of biologically active compounds was present in potatoes of this variety after the production process.

Enhancing microbial fuel cell (MFC) performance in treatment of solid potato waste by mixed feeding of boiled potato and waste activated sludge.

The effects of mixed feeding of boiled potato and waste activated sludge (WAS) on the performance of a microbial fuel cell (MFC) in treating solid potato waste were investigated. The coulombic efficiency (CE) of four MFCs fed with potato cubes containing 0, 48.7, 67.3 and 85.6% of boiled potato was 53.5, 70.5, 92.7 and 71.1%, respectively, indicating enhanced electricity generation and the existence of an optimum mixing ratio. The hydrolysis rate estimated using a first-order sequential hydrolysis model increased from 0.061 to 0.191 day-1, leading to shortening of the startup time for current density reaching its maximum from 25 to 5 days. The final chemical oxygen demand (COD) removal reached 85%. The CE of seven MFCs, fed with raw potato alone, sterilized/unsterilized WAS alone, and four mixed samples of raw potato with sterilized WAS at ratios of 2:1 and 4:1 and unsterilized WAS at 2:1 and 4:1, was found to be 6.1, 43.6, 0.3, 31.0, 16.5, 0.9 and 31.1%, respectively. The hydrolysis rate increased from 0.056 to 0.089 day-1, and the final COD removal changed from 39.5 to 89.6% following the order: potato alone > mixture of potato & WAS > sterilized WAS alone > unsterilized WAS alone.

Evaluation of Food Conservation Technologies for Potato Cubes

Potato cubes of cultivar Innovator were subjected to different food conservation treatments: osmotic dehydration and antioxidants (OD + A), edible coating (E), edible coating with osmotic dehydration and antioxidants (EC + OD + A), immersion in antioxidants (A) and microwave blanching (B). The quality of the products was evaluated by measuring dry matter content, colour, browning index, total phenols and antioxidant capacity and polyphenol oxidase (PPO) activity. Treatments with A resulted in a lower a* colour parameter (red to green) but increased total phenols and antioxidant activity. Those treatments with OD and A together resulted in even larger increases in total phenols and antioxidant activity and also reduced PPO to negligible activity. OD increased dry matter content in OD + A treatments. B increased the browning index (BI) and colour parameters a* and ΔE (total change). As a consequence, potato cubes treated with osmotic dehydration and antioxidants had improved quality characteristics and these treatments are appropriate for minimally processed vegetables.

Use of ultrasound for osmotic dehydration. The case of potatoes

In this work, ultrasound-assisted osmotic dehydration has been implemented as a method to reduce the dehydration time of potatoes. Potato cubes were dehydrated with four types of treatments: static osmotic dehydration, osmotic dehydration with agitation, osmotic dehydration with ultrasound application, and osmotic dehydration with ultrasound pretreatment. Sodium chloride and maltodextrin (12 DE) were used as osmotic agents. For each treatment, various variables were examined for their effect on water loss and solid gain. A microscopic analysis was carried out to evaluate the formation of microchannels and other changes to the potato tissue structure. The effective diffusivity was determined using the analytical solution of the Fick’s second law taking into account the potato shrinkage. Ultrasound treatment resulted in higher moisture and solid mass transfer due to the breaking of cell structure as revealed by microstructure examination. At solute concentration of 30%, ultrasound-assisted osmotic dehydration enhanced the effective diffusivity of water by about 5.5–260%, whereas the ultrasound pretreatment in water increased the diffusivity during osmotic dehydration at solute concentration of 70% up to 130%.

Application of artificial neural network method to exergy and energy analyses of fluidized bed dryer for potato cubes

Drying the samples was performed in the inlet temperatures of 45, 50, and 55 °C, air velocity of 3.2, 6.8, and 9.1 m s−1, and bed depth of 1.5, 2.2, and 3 cm. The effects of these parameters were evaluated on energy utilization, energy efficiency and utilization ratio and exergy loss and efficiency. Furthermore, artificial neural network was employed in order to predict the energy and exergy parameters, and simulation of thermodynamic drying process was carried out, using the ANN created. A network was constructed from learning algorithms and transfer functions that could predict, with good accuracy, the exergy and energy parameters related to the drying process. The results revealed that energy utilization, efficiency, and utilization ratio increased by increasing the air velocity and depth of the bed; however, energy utilization and efficiency were augmented by increasing the temperature; additionally, energy utilization ratio decreased along with the rise in temperature. Also was found that exergy loss and efficiency improved by increasing the air velocity, temperature, and depth of the bed. Finally, the results of the statistical analyses indicated that neural networks can be utilized in intelligent drying process which has a large share of energy utilization in the food industry.

Antioxidant activity of amino acids in soybean oil at frying temperature: Structural effects and synergism with tocopherols.

The purpose of this study was to evaluate amino acids as natural antioxidants for frying. Twenty amino acids were added to soybean oil heated to 180°C, and the effects of amino acid structure on the antioxidant activity were investigated. Amino acids containing a thiol, a thioether, or an extra amine group such as arginine, cysteine, lysine, methionine, and tryptophan had the strongest antioxidant activities. At 5.5mM, these amino acids had stronger antioxidant activities than 0.02% (1.1mM) tert-butylhydroquinone (TBHQ). A functional group such as an amide, carboxylic acid, imidazole, or phenol appeared to negatively affect amino acid antioxidant activity. Synergism between amino acids and tocopherols was demonstrated, and we found that this synergistic interaction may be mostly responsible for the antioxidant activity that was observed. In a frying study with potato cubes, 5.5mM l-methionine had significantly stronger antioxidant activity than 0.02% TBHQ.

Alternative Thawing Methods for the Blanched/Non‐Blanched Potato Cubes: Microwave, Ohmic, and Carbon Fiber Plate Assisted Cabin Thawing

AbstractThe effects of conventional‐C, carbon fiber plate assisted cabinet heater‐CPAC, ohmic‐OT, and microwave thawing‐MT techniques on changes of some quality characteristics and resistant starch (RS) content of potato (Solanum tuberosumL.) cubes (18 × 18 × 18 mm) were investigated. The effects of blanching prior to the freezing on thawing characteristics were also determined. The thawing times of non‐blanched samples were determined as 23,580 ± 485 s, 5360 ± 40 s, 205 ± 18.25 s and 19.26 ± 1.49 s for conventional, CPAC, OT, and MT methods, respectively. The blanching process increased the thawing times in general. OT and CPAC thawing methods served lower RS content for thawed potato samples. The potato cubes thawed by OT and MT were softer than C and CPAC thawed potato cubes (P < 0.05). The highest color change was found for MT of blanched samples and conventional thawing of non‐blanched samples. The electrical methods could be alternative thawing methods in terms of providing shorter thawing times and desirable changes on some quality characteristics.Practical ApplicationsThe conventional thawing of high amount of frozen food products have posed a problem for catering industry. The long thawing time, drip loss issues, quality loses and possible microbial spoilage are lacks of conventional thawing method. The electroheating methods such as ohmic, microwave and unique carbon fiber plate assisted cabinet heating were employed as alternative thawing techniques. Thawing time of potato cubes were shortened and quality characteristics, such as drip loss, texture profile, color properties and resistant starch (RS), were improved by novel thawing methods. The obtained results reveal that the application of alternative thawing methods may lead to decreasing of the operating cost due to shorter process time and minimizing the changes in color, texture and nutritional compounds.

Quality Retention Enhancement in Canned Potato and Radish Using Reciprocating Agitation Thermal Processing

Abstract This study focusses on evaluating the effects of reciprocating agitation thermal processing (RA-TP) on the quality of canned potato cubes and whole radish packed in brine solution (1 % NaCl+1 % CaCl2 solution). Experimental cans were subjected to RA-TP in a lab-scale steam retort at different temperatures (110–130 °C) and reciprocation frequencies (0–3 Hz). Color, texture, antioxidant activity and solids leached into the liquid were evaluated to characterize the quality of processed product. RA-TP resulted in superior quality retention in processed vegetables as compared to static retort (0 Hz) due to the associated shorter (up to 70 %) process times. In general, higher operating temperatures and reciprocation frequencies resulted in better retention of color and antioxidant activity. However, RA-TP also increased texture damage and nutrients/solids leaching, but these negative effects were milder at higher process temperatures. Therefore, high-temperature and high agitation frequency RA-TP concept with shorter process time could be effectively used for better quality retention. The optimal product quality was obtained at 130 °C retort temperature and 3.0 Hz reciprocation frequency for whole radish and at 130 °C retort temperature and 1.5 Hz reciprocation frequency for potato cubes.

Size effects of potato waste on its treatment by microbial fuel cell

ABSTRACTThe performance of microbial fuel cell (MFC) in treating potato cubes with different sizes (the edge size of 3, 5 and 7 mm) was investigated. Current density was found lower as the size of potato cubes increased, even if the differences in their removal were less apparent. At the end of MFC operation for 81 days, both total and soluble chemical oxygen demand reached nearly identical values, irrespective of the potato sizes; and citrate and isobutyrate were two major organic acids remaining in the solutions. Bacterial community analysis using polymerase chain reaction, denaturing gradient gel electrophoresis and sequencing indicated that bacterial species on the anode and in the anodic solution were similar and did not change obviously with potato sizes, and that, in similarity with previous studies on potato-processing wastewater treatment, Proteobacteria and Firmicutes were two dominating phyla. Geobacter was found richer on the anode than in the anodic solutions.

Growth of Staphylococcus aureus in Cooked Potato and Potato Salad--A One-Step Kinetic Analysis.

Staphylococcus aureus is a Gram-positive spherically-shaped bacterium capable of producing heat-stable enterotoxins that cause acute gastrointestinal diseases. The growth of this pathogen in food is a major threat to public health worldwide. Potato salad is a frequent vehicle for infection and food poisoning caused by S. aureus. Therefore, the objective of this study was to investigate the growth kinetics of S. aureus in cooked potato and potato salad. Samples of potato cubes and potato salad inoculated with S. aureus were incubated at temperatures between 8 and 43 °C to observe its growth for developing growth models. No growth was observed at 8 °C. The experimental results showed that the growth curves did not exhibit lag phases, and can be described by a 3-parameter logistic model. A one-step kinetic analysis approach was used to simultaneously analyze all growth curves by direct construction of both the primary and secondary (Ratkowsky square root) models using nonlinear regression to minimize the global residual error. The estimated nominal minimum growth temperature of S. aureus was 6.12 °C in potato cubes and 8.80 °C in potato salad. The estimated maximum growth temperatures of S. aureus in potato cubes and potato salad were very close to each other (46.3 and 46.8 °C, respectively). On the average, the specific growth rates of S. aureus in potato cubes were approximately 70% higher than those in potato salad. This study suggests that cooked potato and potato salad should be stored below 6 °C or above 47 °C to prevent the growth of S. aureus. The mathematical models and kinetic parameters can be used to accurately evaluate the effect of temperature abuse on the growth of S. aureus and conduct risk assessments of S. aureus in cooked potato and potato salad.

Effect of Variable Microwave Power and Vacuum Levels during Dehydration on the Quality Attributes of Potato Cubes

Effect of Variable Microwave Power and Vacuum Levels during Dehydration on the Quality Attributes of Potato Cubes

Comparison of Three Blanching Treatments on the Color and Anthocyanin Level of the Microwave-Assisted Spouted Bed Drying of Purple Flesh Sweet Potato

Browning and a serious drop in anthocyanin level occur during microwave-assisted spouted bed drying (MWSB) of purple-flesh sweet potato (PFSP) cubes. Blanching pretreatment inhibits browning and also affects the drying behavior. Effects of microwave blanching (MWB), hot water blanching (HWB), and steam blanching (SB) were examined experimentally. The results showed that MWB leads to rapid peroxidase (POD) degradation, reduces the drying time, and yields highest anthocyanin level after MWSB drying. However, the color of the dried product was not as bright and purple as those obtained by HWB and SB treatments. Microwave blanching can improve the MWSB drying process to maintain the anthocyanin level in dried products while reducing the drying time.

Purple-Fleshed Sweet Potato Cubes Drying in a Microwave-Assisted Spouted Bed Dryer

Purple-fleshed sweet potatos (PFSP) were loaded into a laboratory-scale, microwave-assisted spouted bed with a coating of sodium alginate (SA) of 0, 0.2%, 0.4%, 0.8% (w/w) for both steam-blanching pretreated and fresh-cut raw samples. The drying curves, rehydration ratio, and maximum penetrating forces were studied for final products; color changes and anthocyanin level were also taken into consideration. It was concluded that coating processing forms barriers to moisture content, which changes the dielectric properties of PFSP cubes and shortens the drying time; however, coating PFSP cubes with SA did not lead to a porous microstructure in the final products. The final hardness was high and rehydration ratio was low. Steam-blanching was helpful for color and anthocyanin-level retention compared with raw samples. In sum, microwave-assisted spouted bed (MWSB) drying of PFSP cubes is not an ideal processing method, even with coating treatment, but blanching is an approach to obtain products with high anthocyanin level and fine purple color.

The effect of pulsed electric field pre-treatments prior to deep-fat frying on quality aspects of potato fries

Abstract The effect of pulsed electric fields (PEF) on potatoes intended for deep-fat frying was investigated. Potato cubes were submitted to 18.9 kJ/kg PEF treatments by applying 9000 pulses at 0.75 kV/cm electric field or 810 pulses at 2.50 kV/cm electric field. Regardless of the process conditions applied, PEF treatments increased moisture and softened potato cubes with no modification on their fresh-like appearance. Potato cubes submitted to PEF also showed a lower oil uptake upon frying than blanched and water-dipped controls. These effects were attributed to the structural modification of potato tissue upon PEF-induced electroporation. The latter could also favour leaching of reducing sugar from potato cubes surface, accounting for a lower browning tendency during frying. Industrial relevance PEF technology could reduce chemical use, process time, water and energy consumption in potato fries production. It could also allow mass transfer to be controlled during frying, improving product colour and reducing oil uptake.

The effect of packaging material and storage period on microwave-dried potato (Solanum tuberosum L.) cubes.

The effect of three packaging materials (transparent biaxially oriented polypropylene laminate (BOPP); semi-transparent BOPP; polyethylene-polyamide (PE-PA) laminate) in three packaging conditions (vacuum, N2, natural atmosphere) and in two temperature treatments (blanching in hot water; steam) on microwave-dried potato (Solanum tuberosum L.; Solanaceae) cubes was studied. After storage for 60 and 120days, the amount of ascorbic acid (AA), shrinkage and rehydration were determined. Dried potato cubes packaged under N2 atmosphere had the highest rehydration value (3.142%). Since there is a direct relationship between the amount of water loss and shrinkage, samples packaged in PE-PA laminate packages under vacuum showed 4.947% less shrinkage than transparent BOPP or semi-transparent BOPP due to low permeability of these packages. Potatoes stored for 120days resulted in 7.89% more shrinkage than those stored for 60days. The least loss in AA occurred in PE-PA laminate packaging. The shelf-life of potato cubes can be increased and their quantitative and qualitative characteristics can be best preserved by package-drying in PE-PA laminate under vacuum conditions.

Optimization of Potato Cube Drying in a Microwave-Assisted Pulsed Spouted Bed

The drying homogeneity of the microwave–pulsed spouted bed drying (MPSBD) method was studied via preparing tubers granules by MPSBD under different predefined conditions. The effects of three parameters (microwave power, moisture content transition point, and loading) on the homogeneity of prepared tubers granules were studied. Based on response surface analysis results, it was concluded that the optimum conditions for tuber granules prepared by MPSBD method is 1.10 W/g microwave power, 80% moisture content transition point, and 90 g material loading. It was proven that the experimental result from the predicted optimal condition agreed with the model-predicted results, which evidenced the accuracy of the response surface analysis. Furthermore, the brighter color and higher rehydration capacity of samples prepared by MPSBD indicates that MPSBD is a promising method that can be applied in the food dehydration industry.

Comparison of free/bi-axial, fixed axial, end-over-end and static thermal processing effects on process lethality and quality changes in canned potatoes

Thermal processing as the most prevalent food preservation technique has been extensively studied and used for years. Different modes of agitation that can be employed in the canning process are characterized by relatively different, heat impacts and their associated quality changes. Hence, the main objective of this study was to evaluate the impact of different retort conditions on lethality (Fo), color and textural changes in potato cubes. Process variables employed were: retort temperature: 115, 120, 125 ºC; agitation orientations: vertical (end-over-end) and horizontal (fixed and bi-axial); agitation speed: 0 (static), 10, 20 rpm. A water immersion single basket rotary retort was retrofitted to simultaneously accommodate agitating modes of rotation. Accumulated process lethality values were calculated for each experimental run. Color quality in terms of parameters such as, yellowness (b-value), total color difference (ΔE values) and textural quality in terms of hardness values were compared for the particles processed under each condition. All process variables had a significant (p < 0.05) influence on Fo, color and texture parameters of potato particles. The quality changes were found to correlate well with the accumulated Fo values achieved during processing. As can be expected, the quality loss increased with an increase in Fo and vice versa.