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Influence of harvest period of goji berries (Lycium barbarum L.) on its antioxidant characteristics

 

 

 

Keywords:

goji fruits, antioxidant activity, polyphenol content, harvest period, food quality

Summary 

The increase in consumer interest in products called superfoods results from their high nutritional density and a marked increase in public awareness of foods with high pro-health values. One of the fruits belonging to this group are goji berries (Lycium barbarum L.), which are characterized by a high content of antioxidant substances, vitamins, minerals and valuable polysaccharides and amino acids. The purpose of this study was to investigate the impact of the goji fruit harvest period on their antioxidant properties. The berries were grown on test plantations on the Crete island in years 2016-2017, harvested in different months of the year. After harvesting, fresh fruit was freeze-dried, and the obtained ethanol extracts from dry fruit were analyzed. In order to characterize their antioxidant properties, the follo­wing qualitative characteristics were examined: antioxidant activity determined by the TEAC assay, total content of polyphenols and flavonoids. The values of TEAC antioxidant activity for the tested goji berries ranged from 3.77 ± 0.19 to 6.4 ± 0.23 μmol Trolox/g d.m.. Differences in antioxidant activity of the tested extracts were found depending on the month of harvest. Fruits harvested in October and November of the following harvest years showed the highest TEAC values. Differences were observed in the content of total polyphenolic compounds and flavonoids in the tested samples from the two-year sets. In 2016, the TPC value averaged 7.23 mg GAE/g d.m., while in 2017 – 9.93 mg GAE/g d.m., a similar upward trend was observed in the results of determining the average flavonoid con­tent, respectively: 3.83 mg catechin/g d.m. in 2016 and 5.07 mg catechin/g d.m. The observed differences may result from the intensity of insolation and the amount of rainfall in particular months in given years of collection and are consistent with the literature data.

 

Prof. UEP dr hab. Katarzyna PAWLAK-LEMAŃSKA

Maja KOŹLAREK

Prof. dr hab. Bożena TYRAKOWSKA

University of Economics and Business

Institute of Quality Science

Department of Technology and Instrumental Analysis

Aleja Niepodległości 10, 61-875 Poznań, Poland

phone: (+48) 61-856-9044

e-mail: This email address is being protected from spambots. You need JavaScript enabled to view it.

 

 

 

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