Fermentation of currant and raspberry leaves and effect on flavonols
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suljettu
Julkaisu on tekijänoikeussäännösten alainen. Teosta voi lukea ja tulostaa henkilökohtaista käyttöä varten. Käyttö kaupallisiin tarkoituksiin on kielletty.
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The aim of this thesis was to gain knowledge on solid state fermentation on raspberry
and black currant leaves. The focus was on the possible increase in polyphenol
content and in particular flavonols. The knowledge is then used to further the
development of a supplement meant for human consumption. Raspberry leaf was
investigated to see if fruit bearing, and insect infestation affected flavonols and
polyphenol content. Flavonols have been found to have health benefits. These include
antioxidant activity, anti-hypertension, anti-obesity, anti-carcinogenic, anti inflammatory properties, which may have therapeutic effects on cardiovascular
diseases, diabetes, and gastrointestinal pains. The use of yeasts and filamentous
fungi have been found to increase polyphenols and antioxidant activity. In this thesis
yeasts Saccharomyces cerevisiae and Torulaspora delbrueckii and filamentous fungi
Monascus anka were used to increase beneficial properties of raspberry and black
currant leaves. There were found subtle signs that the fermentation with the three
different microorganisms did increase antioxidant activity and polyphenol content.
No accurate measurements were found on which flavonols increased during
fermentation due to fermentation proceeding to overfermentation stage. At that stage
all of the identified flavonols decreased. Fruit bearing and insect infested raspberry
leaves were found to have the highest antioxidant activity but not the highest flavonol
content. The highest flavonol content was found in the fruit bearing leaves.