Nauka Przyroda Technologie

2017 volume 11 issue 4 #36 , DOI: 10.17306/J.NPT.2017.4.36

Karolina Młynarczyk, Dorota Walkowiak-Tomczak

The Effect of Technological Treatments and Origin of Raw Material on the Anti-Oxidative Activity and Physicochemical Properties of Elderberry Juice

Summary.

Background. Fruit juices provide numerous bioactive compounds. Elderberry fruits are red and purple due to particularly high content of phenolic compounds, especially anthocyanins, which is also manifested by their high anti-oxidative activity. The selection of adequate fruit pre-treatment conditions may affect the health-promoting properties of juice. The aim of this study was to evaluate the anti-oxidative activity and physicochemical properties of elderberry juices according to the fruit origin and cultivar as well as different conditions of juice processing and preservation (with or without pasteurisation).

Material and methods. Juices were made from wild elderberry fruits (D1, D2, D3) and from ‘Sampo’, ‘Haschberg’ and ‘Samyl’ cultivars grown at plantations. Four variants of juices were prepared: cold-pressed, hot-pressed (60°C, 1 min), pasteurised (90°C, 5 min) and unpasteurised. The juices were subjected to spectrophotometric measurements of the anti-oxidative activity using the ABTS radical, the total phenolic content – using the Folin-Ciocalteu reagent, and the total anthocyanins content – using the differential method. The colour parameters were measured in the CIE L*a*b* system.

Results. The hot-pressed juices exhibited higher anti-oxidative activity and had higher total content of bioactive compounds than the cold-pressed juices. Pasteurisation did not deteriorate the bioactive properties of the elderberry juices. Apart from that, the thermal treatment of fruits before pressing decreased the values of colour parameters L*, a*, b*, C* and h°. This means that hot-pressed juices were darker, with a more purple hue. As far as the origin and cultivar of the fruit are concerned, the juices pressed from a commercial plantation of ‘Haschberg’ elderberries were the most valuable in terms of the properties under analysis.

Conclusions. The thermal treatment of elderberry fruits before pressing improved the juice qual­ity, whereas pasteurisation did not deteriorate the properties under study.

Key words: elderberry, juice, anti-oxidative activity, polyphenols, anthocyanins, colour

Full text available in Polish in Adobe Acrobat format:
https://www.npt.up-poznan.net/pub/art_11_36.pdf

Streszczenie w języku polskim:
https://www.npt.up-poznan.net/tom11/zeszyt4/streszczenie-36.html

Corresponding address:
Karolina Młynarczyk
Instytut Technologii Żywności Pochodzenia Roślinnego
Uniwersytet Przyrodniczy w Poznaniu
ul. Wojska Polskiego 31/33
60-624 Poznań
Poland
e-mail: mlynk@up.poznan.pl

Accepted for print: 30.11.-0001