| dc.description.abstract | Obesity is one of the most concerned health problems, especially in the United States, causing by changing of lifestyle with high consumption of convenient foods (high oil content). Thus, food companies put tremendous efforts on investigating new techniques to produce healthy convenient foods, without compromising on the quality.
In this study, pretreatments including sonication-assisted vacuum impregnation (SVI), non-sonication-assisted vacuum impregnation (NSVI), and sonicated without vacuum impregnation (S) were evaluated, to deliver divalent ions (Mg²⁺) into raw potato slices, and thus enhancing cell structure integrity to reduce fat uptake of chips during frying. The effect of pretreatments was evaluated based on the following product quality attributes: oil content, moisture content, magnesium content, texture, color, shrinkage, densities, and porosity. The effect of using combined ions of Mg²⁺ and Ca²⁺ was also analyzed. Sensory analysis was carried to determine consumer preferences between SVI and NSVI samples. Scanning electron microscopy (SEM) was used to analyze the microstructural changes of potato samples during the processes (sonication and frying).
The combination of sonication and vacuum impregnation (SVI) showed a synergistic effect on reducing oil uptake, with the highest oil reduction values of 20.1% at 50 min treatment time and 16.6% at 30 min sonication time, in comparison to samples pretreated with NSVI and S, respectively. For potato chips treated under SVI, the lowest oil content was obtained at the highest MgCl₂ concentration (20000 ppm) and longest sonication time (50 min), with a value of 0.17±0.01 g/g DM, compared to the control sample of 0.39±0.00 g/g DM. The SVI pretreatment significantly (p < 0.05) affected product texture, color, shrinkage, and porosity.
There was no significant difference (p > 0.05) between potato chips treated with only MgCl₂ and with a combination of MgCl₂ and CaCl₂ on oil content, color parameter a* (greenness-redness), shrinkage, bulk density, solid density, and porosity. They were significantly different (p < 0.05) in term of texture (hardness) as the addition of Ca²⁺ improved the sample’s crispness. The concentration of MgCl₂ affected significantly (p < 0.05) the mass change, water loss, and magnesium uptake. The changes in magnesium content (Mg) was higher for the higher concentration of MgCl₂ for both treatments. SVI treated samples absorbed 29% more magnesium than the NSVI samples for the 15000 ppm solution concentration. For the 50000 ppm solution, the SVI samples absorbed 15% more than the NSVI ones.
Sensory evaluation results indicated that pretreated potato chips (SVI – with 15000 ppm MgCl₂) are acceptable to consumers. Significant difference (p < 0.05) was only observed in the sensory attribute “texture”. Potato chips treated with combined MgCl₂ and CaCl₂ received a significant (p < 0.05) higher score than the other two treatments. Microscopic analysis of SEM images showed a well-intact cellular structure and thicker middle lamella after SVI treatment compared to the control samples.
The application of sonication-assisted vacuum impregnation is effective for reducing oil uptake and improving overall quality of deep-fat fried potato chips, by means of delivering divalent ions into raw potato tissues, stabilizing the cellular structure. | en |
