Nutrient Preservation - John Lockhart founder of Nutricq

With so much food going to landfill, causing environmental damage (by forming the powerful greenhouse gas methane), and in simple terms being wasted, Nutricq decided to focus on preserving nutrients from surplus fresh food. Surplus fresh food is generated by

1) Retailers who understandably need to keep their produce displays appealing to customers

2) Retailers generate byproducts such as fruit peel & pulp in juice bars

3) Producers can generate byproducts that are surplus to requirements.

We are advised to have a broad "colourful" diet, to receive a better range of nutrients from fresh food. Therefore, it made sense for Nutricq to approach nutrient preservation with “a broad brush” and aim to preserve as many different nutritional elements as possible.

Processing many different inputs presents several challenges such as higher and lower moisture levels and more sensitive nutrients in some inputs than others. So, we had to develop a robust system that could accommodate the variables.

How do we preserve nutrients so that end-products retain their health benefits and also have good shelf-life?

Removing moisture is key but there are many different ways to dehydrate fruit and veg.

1.      Sun drying –reliant on the outdoor climate which doesn’t always play fair! Once the item has been sun dried it is usually put in preservative. This means the dried product is well preserved but is not “standalone’.

2.      Freeze drying – a great way to dry product but very expensive in warmer climates where so much energy is required.

3.      Drum drying – effective but requires much energy and can lead to overcooking

4.      Vacuum drying – creating a vacuum where matter is sucked through hot air – effective and can be quicker than drum or spray drying

5.      Spray drying – usually for very wet products like spent yeast. Very expensive in terms of capital cost and process

Airflow is crucial

In any drying method airflow is crucial – whether it be cold air for freeze drying or hot air in other processes, the air has to flow through the product or the product flow through the air.

Generally speaking, the less extremes the material faces, the better the nutrient preservation. But how are extremes measured? Just in temperature? Or in temperature and air exposure? Or in temperature, air exposure and time exposure?

For example, is it better to use lower heat for longer periods with the product relatively inactive during the process (eg on a tray in an oven)?

Or is it better to have the product moving around to circulate in the hot air?

Or is it better to use higher heat temp for shorter periods??

All these factors are important.

Is there any other factor that impacts drying efficiency?

Yes and it’s very important – surface area. The greater the surface area the more the heat+air+time can dehydrate. So, a big round juicy fruit will retain its moisture until the hot air can penetrate through the skin/peel and then the flesh. If we slice and chop the fruit it will dry more quickly because there is much greater surface area exposed.

Heat sensitive products

Water soluble nutrients like vitamin C and pectin will de-nature at relatively low temps so the obvious approach is to heat below the threshold, but this takes quite a long time and requires constant monitoring.

How does Nutricq preserve these sensitive nutrients?

We increase surface area and increase temperature – exposing the product to heat for minimal periods (seconds). We then condition the product to ensure it isn’t retaining heat (so it will not overcook post-process and subsequently eliminate the desired nutrients).

("Nutricq Secret" – it’s not always a disaster to “cook out” nutrients – results can be surprising !!!!)

So, there are many ways to preserve nutrients, but it really depends upon the specific nutrients you are trying to retain and how much time you are prepared to commit.

Effective dehydration of fruit and vegetable can create an antioxidant-rich product with good shelf life …….but…….. effective dehydration aligned with innovative processing can leave you a very high antioxidant product with excellent shelf life……and the excellent shelf life is primarily due to the very high levels of antioxidants! (see our future blog on antioxidants).

So, we can process to preserve sensitive nutrients, or we can process more "aggressively" to harvest more robust nutrients, or process both ways and blend the final products.

Nutricq’s drying facility is flexible and we can adjust the process mid-stream to have more sensitive nutrient retention aligned with the aim of high concentration of certain nutrients.

Without giving too much away we use a vacuum drying principal to preserve nutrients - it gives flexibility that is essential when working with so many different inputs. We can calibrate settings for different challenges and process a vast multitude of inputs with the one setup. Our setup is not necessarily ideal for one-dimensional challenges but gives us broad capability to process just about any input if included with other inputs that balance the overall input spectrum.

We hope you’ve enjoyed this insight and next time we will look at the circular economy that Nutricq operates in.