The Elucidation of Total Polyphenols, Individual Phenolic Compounds, Antioxidant Activity of Three Underutilized Fruit Species—Black Crowberry, Honeyberry, European Cranberry with Their Accumulation

Mojmír Baroň,Pavol Eliáš,Libor Dokoupil,Anna Adámková,Štefan Balla,Jiří Sochor,Tünde Juríková,Jiří Mlček,Monika Ondrášová,Sezai Ercisli,L’uba Ďurišová

doi:10.3390/agronomy11010073

Abstract

Total polyphenols content (TPC), antioxidant activity (AA) and polyphenolic spectrum assay of three underutilized fruit species—black crowberry (Empetrum nigrum), honeyberry (Lonicera kamtschatica) and European cranberry (Vaccinium oxycoccos) is the aim of the present work. TPC and AA assay was performed by spectrophotometry and “individual phenolic compounds” were established by high-performance liquid chromatography. The results showed that TPC ranged from 1.61 ± 0.16 (European cranberry) up to 5.65 ± 0.01 (Black cowberry) gallic acid mg/g fresh weight. The highest value of DPPH (2,2-diphenyl-1-picrylhydrazyl) free radical scavenging assay was determined in black crowberry fruit (7.43 ± 0.34 mmol TROLOX/g fresh weight of fruit). In all samples, the most prevalent phenolic acid was ferulic acid with the highest content in the samples of black crowberry (77.73 ± 3.99 µg/g FW of fruit), black crowberry and honeyberry were present by the highest level of gallic acid (21.82 ± 1.53; 15.07 ± 2.45 µg/g FW of fruit). Honeyberry represented a valuable source of quercetin (12.18 ± 7.88 µg/g FW of fruit), whereas European cranberry and honeyberry are a source of rutin (28.48 ± 0.83 and 27.99 ± 1.78 µg/g FW of fruit, respectively). The results of statistical analyses proved significant differences between cowberry and European cranberry in TPC content and in AA among assayed species. In the same way, statistically significant differences were confirmed in phenolic acids among the assayed species except for European cranberry-honeyberry (in trans p-coumaric, protocatequic and cinnamic acid) and honeyberry-cowberry (in cinnamic acid content). The catechin content is significantly influenced by species (p ≤ 0.05), on the other hand the species has no influence on the resveratrol content (p > 0.05). Each of the studied species can be considered as valuable source of total polyphenols and individual phenolic compounds. Polyphenolic compounds were most frequently accumulated in the vacuole as well as in the outer layers of pericarp.

Highlights

A lot of species of less—known and underutilized berry crop in the territory of Slovakia and honeyberry
Chemical analyses focused on the determination of total polyphenols content (TPC) and antioxidant activity (AA) together with predominant polyphenolic compounds (HPLC method) of less utilized fruit—Empetrum nigrum, Lonicera kamtschatica and Vaccinium oxycoccos
The mentioned species were evaluated in terms of TPC, AA, predominant phenolic acids and flavonoids in berries

Summary

Introduction

A lot of species of less—known and underutilized berry crop in the territory of Slovakia (black mulberries, cornelian cherries, blackberries, blackthorn, rowanberries) and honeyberry Except for the determination of the major bioactive compounds it has been very important to study the accumulation of these compounds for further utilization of fruit in processing. Crowberry (Empetrum nigrum L.) represented less utilized widely distributed wild berries in northern areas [3] with the high content of phenolic compounds. Anthocyanins and flavonols are the most abundant phenolic compounds of fruits [4]. The study of Jurikova et al (2019) tried to connect the study of fruit anatomy of black crowberry (Empetrum nigrum) with detection and quantification of main non-anthocyanin polyphenolic compounds. The mentioned polyphenolic compounds in cells were identificated as rutin, quercetin and catechins, resveratrol, coumaric, p-coumaric, caffeic, ferulic acids, gale, vanilic, syringe, cinnamic and caffeic acids [6]. Despite all health benefits these species have been neglected [12]

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Conclusion