This year's success takes Marmalada's haul of gold medals to five.
Last year, they won with a kumquat and vanilla marmalade and one with grapefruit, mint and white rum.
Their wins have been in the Marmalades with Interesting Additions category.
"It takes 100 hours to develop a recipe," Mrs Duckworth said.
"It's all that trial and error, and the taste tests [by qualified foodies], and trying to get the sugar content down as much as possible, and exploring different textures."
Besides these awards, the company has found major success in the past year with its products included in recipes developed by TV chef Nadia Lim for online food delivery business My Food Bag.
One of their marmalades was used as a glaze on a Christmas ham, which meant they had to provide 5000 jars -- which they did with the help of a group of international UCOL students.