Effects of Cooking on the Bioactivity of Lotus Roots and White Onions

Abstract

Bioactive compounds and antioxidant potentials were determined in fresh lotus roots and subjected to boiling for different periods of time (10, 20, 40, and 60 min). The obtained results were compared with the same indices in fresh and boiled white onions. It was found that fresh vegetables contained higher quantities of bioactive compounds than those boiled for 10 min, and these indices were significantly higher in fresh white onions than in fresh lotus roots (P < 0.05). Polyphenols (mg GAE/g) were 3.65 ± 0.2 a and 10.48 ± 0.5 b ; flavanols (µg CE/g) −44.13 ± 2.8 a and 91.94 ± 4.3 b ; flavonoids (mg CE/g) −0.54 ± 0.02 a and 1.04 ± 0.03 b ; anthocyanins (mg CE/kg) −20.61 ± 1.2 a and 28.34 ± 1.3 b ; and tannins (mgCE/g) −0.58 ± 0.02 a and 1.69 ± 0.03 b of lotus roots and white onions, respectively. The highest antioxidant potential was registered in fresh lotus roots and fresh white onions (10.1 ± 0.70 a and 15.0 ± 0.8 b ; 8.1 ± 0.4 a and 23.05 ± 1.1 b ; 18.7 ± 0.9 a and 26.9 ± 1.3 b µM TE/g for FRAP, DPPH, and CUPRAC, respectively (P < 0.05) and 26.9 ± 1.5 a and 24.14 ± 1.1 a µM TE/g for ABTS (P > 0.05). The influence on tumor cell lines Calu-6 (% of cell viability) of fresh lotus roots (75.61 ± 2.03) and boiling boiled for 10 min (76.54 ± 3.14) was significantly higher (P < 0.05) than for fresh white onions (94.18 ± 3.67) and 10 min (97.02 ± 4.16) white onion. By comparison, the tumor cell lines SNU-601 (% of cell viability) showed similar data for both fresh and boiled vegetables in the range of 86.45 ± 4.07 to 87.28 ± 2.42. In conclusion, the boiling led to a decrease of bioactivity; however, lotus demonstrated higher thermostability than white onions. Three-dimensional fluorescence can be used as an additional index for evaluation of properties. Fresh and boiled (for 10 min) lotus roots and white onions could be considered as a functional food with high antioxidative and antiproliferative activities.

Effect of Heat-Treated Garlic (Allium sativum L.) on Growth Parameters, Plasma Lipid Profile and Histological Changes in the Ileum of Atherogenic Rats

“…In the conducted research, a decrease in the content of total polyphenols, flavonoids, and flavanols was found during the extended time of thermal treatment. The observed trends are confirmed by studies by other authors who suggest that technological treatments may change the phenolic compounds contained in garlic or other plants from the Alliaceae family [40,41]. Blanching for 90 s (G90s) and microwaving raw (GF micro) or blanched garlic (G90s micro) used in the present study led to the lowest loss of bioactive compounds, and the results obtained for heat-treated garlic were comparable with the results of other authors [42].…”

“…In turn, losses of biologically active ingredients under the influence of heating are related, among others, to with the rate of heat transfer into tissues. Heating in water causes the effect of temperature in the entire volume of the material; therefore, it leads to greater losses than heating in air or steam [38][39][40][41], as demonstrated in the present study.…”

“…According to many authors, during processing, mainly thermal, compounds contained in plants may undergo significant changes, often leading to a reduction in their bioavailability or biological activity [38][39][40], which may also be accompanied by a reduction in the antioxidant activity of plants, and thus a reduction in their pro-health effects in the body. Some studies suggest that heating destroys the structure of active sulfur compounds in garlic and causes a significant decrease in the content of polyphenols in Alliaceae plants [39,41,42].…”

The Influence of Plants from the Alliaceae Family on Morphological Parameters of the Intestine in Atherogenic Rats

“…Onion, like garlic, contains inhibitors of lipoxygenase and cyclooxygenase (enzymes that produce inflammatory hormones-prostaglandins and thromboxanes), which, together with the other biologically active compounds contained in it, exert an anti-inflammatory effect in the body [49]. Onions are rich in many biologically active compounds that reduce the risk factors for cardiovascular disease [5,6,8,10,11,22,[50][51][52]. Epidemiological studies show that there is a strong association between a diet high in onion and a reduction in the risk of mortality from ischemic heart disease [3].…”