Vitamin C in fruit juices – effects of source and headspace of package on stability
Tuloisela, Pauliina (2020-10-06)
Vitamin C in fruit juices – effects of source and headspace of package on stability
(06.10.2020)
Julkaisu on tekijänoikeussäännösten alainen. Teosta voi lukea ja tulostaa henkilökohtaista käyttöä varten. Käyttö kaupallisiin tarkoituksiin on kielletty.
suljettu
Julkaisun pysyvä osoite on:
https://urn.fi/URN:NBN:fi-fe2020110689620
https://urn.fi/URN:NBN:fi-fe2020110689620
Tiivistelmä
Ascorbic acid (vitamin C), is sensitive to heat, light, pH level, oxygen concentration and water activity. Its oxidation occurs relatively quickly if these influencing factors are not minimised. Due to its sensitivity, it is important to obtain further information on the stability of vitamin C. The aim of this study is to investigate the effects of natural source ascorbic acid and modified gas mixture composition in headspace on the stability of vitamin C in juices.
Preliminary research was focused on comparing three different existing analysis methods for vitamin C - two chromatographic and one photometric. Methods were evaluated and the most suitable ones for further vitamin C determination were selected based on efficiency, usability and reliability. Raw materials naturally high in vitamin C (orange juice, acerola juice) were compared to artificially produced ascorbic acid stored in three different temperatures. Modification of gas mixture composition with three different adjustments in headspace of a juice package was also investigated in four product lines with two filling heads. During tests the stability of vitamin C and dissolved oxygen level were monitored.
During the tests, vitamin C levels decreased in all samples. In transparent glass bottles vitamin C remained more stable in cloudy juice matrices than in transparent juices. The decrease in vitamin C contents in aqueous samples containing orange juice concentrate with pulp were less than with aqueous solutions of acerola juice concentrate and ascorbic
acid. Most rapid degradation of vitamin C occurred during the first two weeks after pasteurisation regardless of the matrix. Vitamin C stability between the samples containing different headspace gas mixture revealed no significant differences on the vitamin levels. That is why it is not recommended and profitable to modify the parameter
of nitrogen flow given by the equipment manufacturer.
Preliminary research was focused on comparing three different existing analysis methods for vitamin C - two chromatographic and one photometric. Methods were evaluated and the most suitable ones for further vitamin C determination were selected based on efficiency, usability and reliability. Raw materials naturally high in vitamin C (orange juice, acerola juice) were compared to artificially produced ascorbic acid stored in three different temperatures. Modification of gas mixture composition with three different adjustments in headspace of a juice package was also investigated in four product lines with two filling heads. During tests the stability of vitamin C and dissolved oxygen level were monitored.
During the tests, vitamin C levels decreased in all samples. In transparent glass bottles vitamin C remained more stable in cloudy juice matrices than in transparent juices. The decrease in vitamin C contents in aqueous samples containing orange juice concentrate with pulp were less than with aqueous solutions of acerola juice concentrate and ascorbic
acid. Most rapid degradation of vitamin C occurred during the first two weeks after pasteurisation regardless of the matrix. Vitamin C stability between the samples containing different headspace gas mixture revealed no significant differences on the vitamin levels. That is why it is not recommended and profitable to modify the parameter
of nitrogen flow given by the equipment manufacturer.