Cooking impact in color, pigments and volatile composition of grapevine leaves (Vitis vinifera L. var. Malvasia Fina and Touriga Franca)

Abstract

Grapevine leaves (Vitis vinifera L. var. Malvasia Fina and Touriga Franca) under culinary treatment (blanching and boiling at 60, 75 and 90min) were studied for their color, pigments and volatile fraction changes. Blanching and boiling caused a decrease in luminosity and a loss of green coloration in both varieties, while a yellow-brownish color arose. Significant correlations were established between the loss of green color (monochromatic variable a) and the total chlorophylls content. The main volatiles in fresh leaves [(Z)-3-hexenal, (Z)-3-hexen-1-ol, and (Z)-3-hexenyl acetate] were drastically reduced by blanching and suppressed by boiling. Other compounds like pentanal and 6-methyl-5-hepten-2 one arose from blanching and boiling. A boiling time of 60min is adequate for the culinary process of grapevine leaves, since the product is considered edible and the pigments and volatile changes are not as drastic as observed at 75 and 90min of boiling.

Comparison of Different Categories of Slovak Tokaj Wines in Terms of Profiles of Volatile Organic Compounds

“…For semiquantitation purposes, relative concentrations (crel) of VOCs were calculated by the ratio of each individual peak area to the area of internal standard and converted to concentration equivalents based on the internal mass added [29].…”

Effect of brewing conditions on pigments and total polyphenols content and biological activities of theAcantholippia deserticola (Phil.)infusion

“…This might be due to an increased extraction over chlorophyll a over time, or to an increase in chlorophyll b degradation over time. Lima et al (2017) report that the thermostability of chlorophyll a is greater than that of chlorophyll b. This is however, in contrast with findings by Koca et al (2007), who found chlorophyll b to be more stable than chlorophyll a.…”

“…Similar trends were observed for the different herbal masses used, the greatest extraction being achieved with brewing times between 2 and 5 min (p < 0.05), in agreement with the changes seen for the chromatic coordinates and color parameters. Beyond that time, pigment levels returned to their initial values, possibly due to the degradation caused by temperatures and oxygen exposure (Lima, Pereira, Baraldi, & Malheiro, 2017;Pumilia et al, 2014). Chlorophyll levels were higher than pheophytin levels, thus offering a plausible Figure 1.…”

Effect of grape ( Vitis vinifera L.) varieties and harvest periods on bioactive compounds, antioxidant activity, phenolic composition, mineral contents, and fatty acid compositions of Vitis leave and oils

“…Polyphenols of grape by‐products such as leaves, seed, and skin are rich in bioactive compounds. Bioactive phytochemicals are found in grape leaves for consumers and industries for culinary purposes (Anđelković, Radovanović, Anđelković, & Radovanović, 2015; Babalık & Göktürk Baydar, 2019; Borai et al., 2017; Fenglin, Ruili, Bao, & Liang, 2004; Lima, Pereira, Baraldi, & Malheiro, 2017; Radovanovic, Andjelkovic, Radovanovic, Milenkovic‐Andjelkovic, & Dekic, 2015). Grapevine leaf composition is influenced by soil properties and the vegetative stage (Páscoa, 2018).…”