News From Agriculture And Life Sciences Division, Lincoln University
The stalks have it: new sources of antioxidants
By Janette Busch
Most of us will remember our mothers telling us to eat our vegetables because it would make our hair curl. While she may
have been wrong about our hair curling she was certainly right about the importance of eating vegetables.
Dr Alaa El Din Bekhit and Dr Sue Mason from the Food Group at Lincoln University have investigated the use of plant
parts that are usually discarded as waste by growers and manufacturers (an economic loss) to develop new value-added
foods and eliminate environmental concerns about waste disposal and pollution.
As a result of global environmental changes, urbanisation and increased natural disasters, arable land is decreasing in
availability and food shortages are becoming chronic in some countries.
There is a need to revise the current use of raw materials available for food and utilise them in order to minimise
waste.
Most of the recent research into the distribution of antioxidants in plants has focussed on the parts of the plant that
are already commonly eaten.
"In New Zealand we tend to eat only certain parts of plants (such as roots and leaves) while in other countries as much
of the plant as possible is used for food, either fresh or after they have been processed into products," said Dr
Bekhit.
Dr Bekhit and his team took cabbage; broccoli and cauliflower stems discarded by the growers and measured their
antioxidant contents. Each vegetable (individually) was seasoned with spices, covered in brine and allowed to ferment.
The antioxidant levels of the stalks were measured before and after fermentation.
"While the antioxidant levels did reduce a little after processing as expected,” said Dr Bekhit, "they still remained at
a beneficial level. In fact, one fermented vegetable stalk contained the four times the levels of antioxidants as the
equivalent weight of tomatoes." The fermented samples were then subject to a taste test by people from three different
ethnic backgrounds (New Zealand, Asian (mainly Chinese) and others). They were given a small sample of the new product
to eat and asked to give their opinion.
"Not surprisingly, we found that people who were familiar with similar fermented products through ethnicity or overseas
travel made more favourable comments," said Dr Bekhit. "We are encouraged by this because it suggests that products such
as this will have a ready made niche market in New Zealand, while reducing the economic loss from discarding the waste.”
"What often happens with a new food product is that, over time, it can move from being a niche product to a mainstream
one and this is what we hope will happen when this product (and other similar ones) become available commercially."
This research was presented at the New Zealand Nutrition Society Conference and was well received for its innovative use
of a waste product that would be of benefit not only to consumers but also to the environment. The raw material was
kindly provided by Mr Max Lilley of M and M, Canterbury.
ENDS