Lemon myrtle (Backhousia citriodora) is a myrtaceae shrub and is native to Australia. It is cultivated and produced mainly in Queensland, northwest Australia, and is rich in aromatic oils. Currently, lemon myrtle is used as one of the ingredients of blended tea or as a substitute for lemon flavor in milk-based foods such as bread, pasta, syrup, liqueur, spices, cheese cake or ice cream.
This study was aimed to investigate the quality characteristics and consumer acceptability of jellies added with lemon myrtle extract.
Lemon myrtle leaves were extracted for 0, 3, 5, 7, 9 minutes in 90℃ water and used for jelly preparation. The moisture content, water activity, pH, color, texture, total polyphenol content, antioxidant activities and sensory properties of the jelly were evaluated.
Moisture content of the jelly ranged from 79.14 to 80.66% ; a control sample showed the lowest value by 79.14% and the content increased significantly as the extraction time of lemon myrtle increased. There was no significant difference in water activity among test samples.
The pH of L0(control) was significantly high by 6.09 and increased significantly with the increase of extraction time. In color the lightness(L) value was the lowest in a L3 sample. The redness(+a) showed the lowest value in the L9 sample, and significantly decreased as the lemon myrtle extraction time increased. Yellowness(+b) showed
the lowest value in the L0 sample and the highest value in the L9 sample, and significantly increased with the extraction time of lemon myrtle. In texture properties the hardness of L9 sample showed the highest value and the lemon myrtle extraction time increased significantly. The cohesiveness was highest in the L0 and lowest in the L5 sample. Gumminess and chewiness increased significantly with increasing extraction time. The total polyphenol content was the highest in the L5 and the jellies with lemon myrtle extracts were significantly higher than that of the control(L0). In DPPH radical scavenging activities of L0, L3, L5, L7 and L9 were 1.51%, 62.07%, 78.84%, 78.53%, and 79.23%, respectively. ABTS radical scavenging activity of the L0 sample was the lowest, while there were no significant differences among L3, L5, L7, and L9 samples. In sensory evaluation overall preference, color, sweetness, texture, and lemon myrtle flavor did not show any significant differences among samples.