Väitös (elintarvikekehitys): MSc Liz Gutiérrez Quequezana

MSc Liz Gutiérrez Quequezana esittää väitöskirjansa ”Effect of Cultivar, Growth Environment and Developmental Stage on Phenolic Compounds and Ascorbic Acid in Potato Tubers Grown in Finland” julkisesti tarkastettavaksi Turun yliopistossa maanantaina 18.12.2023 klo 12.00 (Turun yliopisto, Medisiina C, Osmo Järvi -luentosali, Turku).

Yleisön on mahdollista osallistua väitökseen myös etäyhteyden kautta: https://utu.zoom.us/j/65531749123

Vastaväittäjänä toimii professori Agnieszka Kita (Wroclawin ympäristö- ja biotieteiden yliopisto, Puola) ja kustoksena professori Baoru Yang (Turun yliopisto). Tilaisuus on englanninkielinen. Väitöksen alana on elintarvikekehitys.

Väitöskirja yliopiston julkaisuarkistossa: https://urn.fi/URN:ISBN:978-951-29-9569-1 (kopioi linkki selaimeen).

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Tiivistelmä väitöstutkimuksesta:

The annual value of potato (Solanum tuberosum L.) consumed worldwide exceeds USD 10 000 million. Only corn, rice and wheat of the staple crops exceed the volume of potato. It provides us essential carbohydrates, proteins, fiber, vitamins, minerals, and antioxidants such as carotenoids, and phenolic compounds. Purple-fleshed potatoes, naturally occurring in the Andes, are particularly rich in anthocyanins, antioxidants known to combat oxidative stress for potential health benefits.

This study focused on developing reliable methods for extracting the target compounds from potatoes. Freeze-drying was proved to be crucial in enhancing the extraction efficiency of anthocyanins and vitamin C. This study also identified suitable solvents and reducing agents to optimize the recovery of the analytes.

The greenhouse and field experiments showed that the content of anthocyanins, phenolic acids, and vitamin C in the tubers primarily depends on the cultivar type. The highest concentrations of these compounds were observed between 70 and 80 days after planting, declining with tuber maturity.

Cold temperatures generally increase phenolic compounds in the upper plant organs, but little is known about their impact on underground organs like potato tubers. When grown under controlled temperatures (13 and 18 °C) no significant differences were found in the content of anthocyanins, phenolic acids, and vitamin C in the purple-fleshed tubers.

Field studies performed at different latitudes (61 and 64° N) over two years (2014 and 2015) revealed significant variations in tuber composition. Warmer and drier weather conditions led to lower levels of anthocyanins, phenolic acids, and vitamin C in potato tubers. Conversely, moderate temperatures (13-18 °C) with good precipitation resulted in tubers with the highest content of phenolic compounds and vitamin C. Thus, the hot and dry weather conditions produced tubers with lower nutritional value.
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