Effect of pre-drying and par-frying conditions on the crispness of French fries

Abstract

An experimental design was used to study the effect of pre-drying (to 10, 15 and 20% weight loss) and par-frying conditions (160, 170 and 180 • C) on the crispness of French fries. Par-frying time was adjusted with a software program to obtain equal moisture content and internal texture for all samples. Crispness was evaluated with a sensory panel. Furthermore, samples were analysed with a texture analyser and with confocal scanning laser microscopy (CSLM). Parfrying at 180 • C resulted in a crispier product than at 160 and 170 • C. Pre-drying to 20% weight loss lead to blisters and reduced crispness in comparison with pre-drying to 10 and 15% weight loss. Instrumental texture measurements showed a good correlation with sensory crispness. Large differences in cell structure, such as blisters, could be observed with CSLM. CSLM was useful to explain results from the instrumental and sensory texture evaluation.

Direct observation of the surface structure of French fries by UV–VIS confocal laser scanning microscopy

“…Thus, the positive effect of airdrying toward oil uptake reduction could be the restriction of the connections between cells layers and thus the limitation of the oil percolation network. This interpretation is supported by some experimental observations of oil uptake limitation associated to the formation of blisters in the surface of air-dried and fried potatoes (van Loon et al, 2007). These puffing phenomena can be due to the accumulation of water vapour under the compact superficial cell layers impermeabilized to the mass transfers by the pre-drying step.…”

Effect of pulsed electrical fields on the structural properties that affect french fry texture during processing

“…A reduction in oil uptake of 38.7% was obtained in the chips that were PEF treated and only 3.8% reduction was achieved in blanching treated samples (Janositz, Noack, & Knorr, 2011). During frying, water vapour forms a barrier for oil penetration (Van Loon et al, 2007) and PEF decreases oil uptake by facilitating water diffusion from the core of the potato strips to the surface, creating a thicker water vapour layer that leads to reducing dehydration and oil uptake. Reduction in oil uptake in the PEF treated potatoes can also be explained by the smoother surface of the PEF treated tissue leading to a better oil drainage after frying (Thanatuksorn, Pradistsuwana, Jantawat, & Suzuki, 2005).…”

Effect of starch retrogradation on texture of potato chips produced by low-pressure superheated steam drying

“…Force-deformation data were recorded to determine the textural characteristics of the chip. The maximum force of break, area under the force-deformation curve (Rosenthal, 1999) and the number of peaks (van Loon et al, 2007) in the force-deformation curve of each sample were considered as an indication of hardness, toughness and crispness of the sample, respectively. All tests were performed in duplicate and the average values were reported.…”

“…The texture of dried potato chips is reported in terms of hardness, toughness and crispness, which were indicated from the maximum breaking force, area under the force-deformation curve (Rosenthal, 1999), and the number of peaks (van Loon et al, 2007), respectively. The results of these parameters are listed in Table 6 while a typical force-deformation curve of dried potato chip is illustrated in Fig.…”