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Abstract: The images of commercial potato chips were evaluated for various colour and textural features to characterize and classify the appearance and to model the quality preferences of a group of consumers. Features derived from the image texture contained better information than colour features to discriminate both the quality categories of chips and consumers’ preferences. Entropy of a ∗ and V and energy of b ∗ from images of the total chip surface, average and variance of H and correlation of V from the images of spots and/or defects (if they are present), and average of L ∗ from clean images (chips free of spots and/or defects) showed the best correspondence with the four proposed appearance quality groups (A: ‘pale chips’, B: ‘slightly dark chips’, C: ‘chips with brown spots’, and D: ‘chips with natural defects’), giving classification rates of 95.8% for training data and 90% for validation data when linear discriminant analysis (LDA) was used as a selection criterion. The inclusion of independent colour and textural features from images of brown spots and/or defects and their clean regions of chips improved the resolution of the classification model and in particular to predict ‘chips with natural defects’. Consumers’ preferences showed that in spite of the ‘moderate’ agreement among raters (Kappa-value =0.51), textural features have potential to model consumer behaviour in the respect of visual preferences of potato chips. A stepwise logistic regression model was able to explain 86.2% of the preferences variability when classified into acceptable and non-acceptable chips. [Copyright &y& Elsevier]

BSTRACT Texture of potatoes with different shapes (slices and strips) were evaluated after frying and in some cases after baking. Blanched and unblanched potato slices (Bintje variety) were fried at four oil temperatures: 160, 170, 180 and 190C until reaching a moisture content of ∼1.7%. A puncture test with three point support for the slices was applied to measure the texture of potato chips using the following parameters extracted from the force versus distance curves: maximum force of break (MFB) and deformation of break (DB). These two parameters were useful to follow the changes in texture of the fried slices with moisture content at different frying temperatures. Blanched and unblanched potato strips were partially fried at 160C and 190C for 60, 90 and 120 s. The par-fried potatoes were frozen at -20C for one day after which they were baked at 200C for 15 min. The texture of the baked potato strips was evaluated using a bending test with two support points. From the force versus distance curves, two parameters were extracted: maximum force of deformation (MFD) and maximum deformation (MD). Significant higher MFB and lower DB values (P > 0.1) for unblanched fried slices indicate that these are crispier than blanched chips for moisture contents lower than 4% (6.59 N and 0.62 mm vs 5.74 N and vs 0.75 mm for unblanched and blanched chips, respectively, average values for the four frying temperatures employed). There was no effect of the frying temperature and the pretreatment (blanching or unblanching) on the texture of the frozen par-fried potatoes after baking when compared at the same residual moisture content, but blanched potato strips lost moisture more slowly both in frying and in baking. [ABSTRACT FROM AUTHOR]

A simple method is proposed to quantify volume of potato chips by measuring the displaced volume of a finely granular material (rape seeds) by the volume of the chips. Firstly, compaction of the seeds was studied to evaluate the reproducibility and accuracy of the technique. The results obtained indicate an encouraging potential of the technique to estimate the apparent volume of potato chips and give some indications of variation of chip apparent density with some important technological parameters such as chip thickness, frying temperature, and pretreatment of the slices before frying (e.g., blanching). This technique showed that the apparent volume of un-blanched potato slices increased clearly (P = 0.007) with frying temperature (from 120°C to 190°C) until the chips reached final moisture contents <3% (wet basis). For 180 and 190°C, the final apparent volume of these samples indicated that the chips expanded in ∼6% beyond its original volume before frying (14.1 mL). For potato slices blanched in hot water (80°C and 3.5 rain) and fried under the same temperature intervals and conditions, this trend was not statistically significant (P = 0.088), and the average apparent volume of the chips was 10.9 mL which correspond as an average to a shrinkage of ∼23%. [ABSTRACT FROM AUTHOR]

Abstract: Pairs of potato slices were blanched, soaked in a NaCl solution or water and fried. The originally adjoining faces of the chips were analysed for average color by digital photography and image analysis. Stepwise increases in blanching temperature (60, 65, 70, 75, 80°C/5min) gave rise to gradually darker chips above 65°C, by a total of units . Slices soaked after blanching in a 3% NaCl solution for 5min were consistently paler by units than those soaked in water only. Change in the concentration range 0.6–9% NaCl was found using one-tailed paired t-test, subsequent to blanching at 70°C/5min . [Copyright &y& Elsevier]