| Project Name: | Tomato Waste as a Feed Ingredient – Part 1 |
|---|---|
| BPA Number: | 10 |
| Funding Round: | December 2013 |
| Report(s): | Tomato waste as a feed ingredient |
| For enquiries contact: | Mathew Cumming, Ivan Kurtovic, Sue Marshall and Lynne Scanlen, PFR, Donato Romanazzi, Cawthron Institute. |
| Phone: | |
| Email: |
Summary of Project and Key Findings:
Preliminary work by the Cawthron Institute has shown that tomato waste (pomace) contains high levels of desirable nutritional components and the overall composition could fit well into a feed formulation. Based on some initial data, tomato waste may have potential as a sustainable and alternative fish feed ingredient or it could be added as functional ingredient to other animal feeds.
The aim of this scoping project was to understand the characteristics and chemical composition of the tomato pomace, as a first step to evaluate the potential uses of this by-product, particularly as additive or functional ingredient in aquaculture feed formulations. The table below summarises the composition of the dry tomato pomace obtained from Heinz-Wattie’s New Zealand.
Tomato pomace composition
| Analysis | Result | Units |
|---|---|---|
| Energy | 845 | kJ/100g |
| Crude protein | 18.8 | g/100g |
| Total fat | 10.1 | g/100g |
| Total sugar | 2.3 | g/100g |
| Total dietary fibre | 56.0 | g/100g |
| Ash | 3.9 | g/100g |
| Carbohydrates | 8.9 | g/100g |
| Total phenolics (as gallic acid) | 0.2 | g/100g |
| Total vitamin E | 4.6 | mg/100g |
| Lycopene | 470 | mg/kg |
| β-carotene | 15 | mg/kg |
| C18:2w6 linoleic acid | 5.2 | g/100g |
| C18:1w9 oleic acid | 2.2 | g/100g |
| Total amino acids | 174.7 | mg/g |
Tomato pomace contains significant levels of protein and reasonably high levels of all essential amino acids. Both of these make it a suitable candidate as a feed ingredient. The pomace also contains a significant amount of bioactive phytochemicals, which seem to be able to withstand industrial processing methods. Among those compounds, carotenoids (lycopene and β-carotene) are the most abundant in the tomato waste and are well known antioxidants. Lycopene could be a potential substitute for astaxanthin in salmon feed.
The fatty acids profile showed high levels of unsaturated fatty acids, similar to other vegetable oils used in animal feeds.
The high total dietary fibre content could be a limiting factor for using the tomato pomace as a feed ingredient. However, preliminary experiments showed that enzymatic digestion can reduce the fibre content by up to 80%. Further experiments to optimise the enzymatic digestion conditions are required.
Experiments on the effect of tomato pomace on the function of digestive enzymes from both Chinook salmon and of porcine origin showed no significant inhibition. Endogenous lipase and protease (chymotrypsin/elastase II-like activity) was present in the commercially produced tomato pomace and these enzymes could aid digestibility if added to feeds.
From all the data gathered in this scoping project, tomato pomace could fit well into a feed formulation as a minor component to enhance the health benefits of the final feed.
In the next phase of the project, we aim to develop a manufacturing process for producing tuneable animal feed and/or human functional food ingredient products from tomato pomace.
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