engleski

Stability of olive leaf drink upon storage at different temperatures

The basic product of olive tree is olive oil from fruit. Other parts of plant like leaves, remain unused. Many studies have shown that olive leaf extracts have anticancer, antiinflammatory and antimicrobial properties due to polyphenols, which makes olive leaf a good source for functional food production. Olive leaf drink due to it valuable compostion present functional drink itself. Knowing that, this research aimed to investigate the stability of olive leaf drink during 9 weeks at different temperatures (8, 22 and 30 °C). Influence of storage time and storage temperature was monitored by analysis of total phenols, antioxidant capacity by DPPH, color parameters (L*, a*, b*, ΔE) and sensory properties of olive leaf drink samples. Obtained results showed that total phenols slightly decreased during storage, being most stabile on 8 °C. Antioxidant capacity showed approximately similar trend. Color of olive leaf drink changed by the storage time as L* decreased and ΔE increased in all samples. The highest ΔE values were observed at 30 °C. Sensory analysis confirmed that olive leaf drink became darker color by storage time and temperature. Intensity of authentic odor and flavor slightly decreased with time, especially on higher temperature. Intensity of the main taste attributes (astrigent and bitter taste) decreased by storage duration and on higher temperature, resulting with higher scores for harmony taste. In general, obtained results showed satisfied stability of olive leaf drink especially at 8 and 22 °C, suggesting its functional product potential.

olive leaf, stability, phenols, color, sensory

Ovaj rad je izrađen u okviru projekta „Primjena inovativnih tehnologija u proizvodnji biljnih ekstrakata kao sastojaka funkcionalne hrane“, HRZZ-3035 te potpore Sveučilišta u Zagrebu „Optimiranje postupka pripreme te stabilnost tijekom skladištenja ledenog čaja na bazi lista masline“.