The stalks have it: new sources of antioxidants
News From Agriculture And Life Sciences Division, Lincoln University
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.