Phenolic profile of fresh and frozen nettle, goutweed, dandelion and chickweed leaves
2017
Augspole, I., Latvia Univ. of Agriculture, Jelgava (Latvia). Faculty of Food Technology. Dept. of Chemistry | Duma, M., Latvia Univ. of Agriculture, Jelgava (Latvia). Faculty of Food Technology. Dept. of Chemistry | Ozola, B., Latvia Univ. of Agriculture, Jelgava (Latvia). Faculty of Food Technology. Dept. of Chemistry | Cinkmanis, I., Latvia Univ. of Agriculture, Jelgava (Latvia). Faculty of Food Technology. Dept. of Chemistry
Worldwide it is of great interest to find new and safe antioxidants from natural sources. Green leafy vegetables and wild plant leaves are healthy nutrients, containing vitamins, minerals and biological active compounds, therefore these plants provide beneficial health effects due to the presence of antioxidant compounds. It is useful and popular to supplement human diets with fresh or frozen edible plants. It is known that freezing may help to preserve the quality of plants, and is superior to other preservation methods. The aim of research was to compare the phenolic compounds content of fresh and frozen edible wild plants leaves grown in Latvia. The samples were processed using freezing -20 °C and for a comparison fresh samples were analysed. The leaves of stinging nettle (Urtica dioica), common goutweed (Aegopodium podagraria), dandelion (Taraxacum officinale) and chickweed (Stellaria media) were collected in May 2016 in Latvia. In the current research the content of total phenolics was determined in four types of fresh and frozen plant leaves and they can be arranged as follows (starting from plant with less phenolics content as gallic acid equivalent): dandelion, chickweed, goutweed, nettle. The freezing process affected the values of extracted phenolics and results in an increase in the extractability of the polyphenols for about 9.3%. Using HPLC analysis, we quantified 21 different individual phenols. The eight most abundant phenolics were: catechin hydrate, protocatechnic acid, α-resorcylic acid, vanillic acid, sinapic acid, routine, quercetin, luteolin, kaempferol. Experimentally it was ascertained, that in the frozen plant samples contents of some polyphenols increased (p=0.007), compared to the fresh samples.
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