INVESTIGATING OPPORTUNITIES FOR ONION WASTE

The 2023 onion growing season has been a challenging one for growers – and an interesting one for me as a new person in the industry. Onions New Zealand has started a project looking at adding value from waste and I was very privileged to be selected as the summer student to undertake this work.

My name is Grace Petersen and I have just completed my Bachelor of Science in Human Nutrition and am about to start my Master of Applied Science in Advanced Nutrition Practice during 2023. Living on a sheep and beef farm in Hawke’s Bay and working for many seasons in a crop monitoring role for the apple industry has provided me with a real appreciation of the value of the horticulture sector to our region and New Zealand.

The Onion Waste Stream Project will complement work for the Sustainable Food and Fibre Futures (SFFF) Humble to Hero programme, which is aimed at differentiating New Zealand onions from those produced in the rest of the world.

The project has been structured using a series of interviews with growers to gain an understanding of the volumes and characteristics of their crops and the underutilised waste that is generated following harvest.

This waste, or unmarketable onions, means growers incur an economic loss for a percentage of their crop. I am currently in the process of finishing grower interviews, collating the information and analysing the results, to understand the potential for added value from those products that are currently waste streams.

Although onion is one of the few ingredients consumed daily in most households, it is typically labelled as a timeconsuming ingredient to prepare. Many meals, snacks and sauces require onion as one of the key flavour ingredients, and some consumers now switch the whole onion out for a dried powder alternative. This is an opportunity for New Zealand’s onion growing industry, as onion powder includes the bulb and can also include dehydrated onion skins, leaves and roots.

Onion juice is another solution that the industry could look at for waste utilisation. Thanks to the high amounts of vitamins, minerals and antioxidants, such as vitamin C and quercetin, onion juice has been shown to be beneficial in health aspects such as immunity function, and to fight off inflammation within the body. Other options include a quercetin rich extract derived from onion waste which could be looked at as a nutritional supplement for human health. Quercetin is found in higher concentrations in the onion skin rather than the onion bulb itself, and is known for its many health benefits such as reducing the risk of some cancers and supporting sports recovery and performance.

It has been very humbling to have growers give me their time in what is a busy time of the year, and a particularly challenging season when the weather has impacted heavily on crop yields and survival. I have really appreciated the fact that growers have still taken the time to talk with me while they have been trying to deal with other issues on the farm.

It has been interesting to understand a couple of the key issues raised by growers. In many cases, growers understand the opportunity inherent in turning waste into a product that has value, but making it a reality is an entirely different challenge. In some cases, it is a cost for growers to have their waste removed into other uses like feed for the livestock sector. One thing is clear, converting onion waste into an added value product has the potential to increase the resilience of the sector by increasing and diversifying income streams.

I am now going to spend some time with the team at Onions New Zealand to understand the information gained from grower interviews and the enthusiasm of growers to do some more work in this area. It is interesting to note that other horticulture sectors are also looking at these types of opportunities and some collaboration may be possible here as well.

Many thanks to all of you that have given your time and insights into my work. I head back to university at the end of February, but I will be working with the team at Onions New Zealand to ensure that the results of my project are communicated back to the sector. I am keen to stay connected with the sector and look forward to seeing further outcomes from my work.