The Effect of Thermal Treatment on Selected Properties and Content of Biologically Active Compounds in Potato Crisps

Abstract

The aim of this study was to determine the effect of blanching and frying on selected properties of potato crisps of yellow- and purple-fleshed cultivars. The material used was yellow flesh cv. Ismena and purple flesh cv. Provita. Potato slices were blanched (1–5 min at 80–90 °C) and then fried (155–175 °C). The control sample was comprised of crisps that were not blanched. The fat content and color parameters were determined in crisps, while in defatted samples, the following were determined: the content of total polyphenols; antioxidant capacity, measured by the ability to scavenge the ABTS•+ radical cations (TEAC ABTS) and by the FRAP method; and the level of fluorescent intermediary compounds (FICs) and browning index (BI), as indicators of the progress of the Maillard reaction. The content of kynurenic acid (KYNA) was examined in the raw material, in slices, in the water after blanching and in the crisps. Blanching affected the fat absorption, with time being more critical than temperature. The color of crisps from yellow flesh potatoes after blanching lightened, while the color in the purple samples darkened. The content of total polyphenols was higher in purple crisps. Increasing the temperature and shortening the time of blanching increased the polyphenol content and the antioxidant capacity. Blanching decreased the level of FICs, while frying increased FICs. Higher BI values characterized the crisps from cv. Provita. Blanching reduced BI values by 50%, while frying at highest temperature increased these values. The content of KYNA in purple potatoes was almost three times higher than in yellow ones. Blanching and frying decreased the KYNA content in potatoes and fried crisps.

Determination of kynurenic acid in Linum usitatissimum L.

“…leaves of basil (14.08 µg/g) and thyme (8.87 µg/g), as well as other spices and herbs (Turski et al, 2015). Flax seeds showed a similar level of KYNA as measured for the fruits of black pepper (0.1 µg/g) or for raw potato tubers (0.226-0.683 µg/g FW) (Kita et al 2022). However, potato tubers may be consumed only after thermal processing, and this process signi cantly decreases the level of KYNA.…”

“…cauli ower, broccoli and potatoes, was at a very low level, in the range 0.04-0.41 µg/g FW (Turska et al, 2022). In the case of potato cultivars with yellow (Ismena) and purple esh tubers (Provita), the KYNA level was slightly higher at 0.226 and 0.683 µg/g FW (Kita et al, 2022).…”

Content and Stability of Hydroxycinnamic Acids during the Production of French Fries Obtained from Potatoes of Varieties with Light-Yellow, Red and Purple Flesh

“…The lower stability of phenolic compounds when exposed to high temperature is confirmed by many authors [5,13,14,26,54,55]. Van Boekel et al [54] report that the cooking process of various vegetables causes softening, damage to the cell wall and release of compounds contained in it.…”

“…They also contain health-promoting compounds with antioxidant activity (AA), i.e., vitamin C and phenolic acids [1][2][3]. These potatoes can be used for direct consumption after cooking, the production of dried or fried potato snacks, i.e., potato chips and French fries [4][5][6]. Taking into account the health and safety of consumers, as well as the fact that plant raw materials with health-promoting properties (containing valuable biologically active compounds) are increasingly used in food production, the scientists took into account the still not very popular potatoes with colourful flesh (red and purple) [7][8][9][10].…”

A Review of the Health Benefits of Food Enriched with Kynurenic Acid

“…The comparison of 16 different edible potato varieties grown under similar soil and climatic conditions showed up to 10-fold differences in KYNA content, from 0.04 to 0.65 μg/g wet weight [ 76 ]. Similarly, the comparison of yellow- and purple-fleshed potato cultivar Ismena and Provita revealed a threefold difference in KYNA content, 0.226 and 0.683 μg/g wet weight, respectively [ 81 ]. The origin of KYNA in plants is poorly understood.…”