HGA newsletter, autumn 2004
Background
Hazelnuts have found their way into more non-traditional foods due to the recognition of its nutritional and nutraceutical properties. Among nut species, hazelnuts play a major role in human nutrition and health because of its special composition of fatty acids ( mainly oleic acid), fat soluble bioactives ( tocopherols and phytosterols), vitamins (vitamin E), minerals, amino acids, antioxidant phenolics and dietary fibre. Hazelnuts provide an excellent source of energy (631 kCal/100g) due to its high oil content (~61%). Besides nutritional value, the presence of taste-active components together with aroma-active components can improve the taste and flavour of hazelnut-based products.
The presence of palmitoleic acid allows hazelnut oil to be absorbed quickly into the skin as well as acting as a solar UV filter, thus making it an excellent carrier oil and ingredient in skin preparations.
Elevated serum cholesterol level is a well-known risk factor for coronary heart disease and is a leading cause of mortality in many countries around the world. Monounsaturated fatty acids which are in large quantities in hazelnut oil, are known to decrease the low-density lipoprotein cholesterol levels and decrease the risk of heart disease. Research has demonstrated that hazelnut supplementation (40g) in the diet results in total cholesterol, low-density lipoprotein cholesterol, very low-density lipoprotein cholesterol, triacylglycerol Apo B and homosistein reduction of up to 5.3, 2.6, 22.4, 5.3, 0.3, 10.4, and 7.8% respectively. Furthermore, hazelnuts in the diet increases high-density lipoprotein cholesterol and Apo A by 13.9 and 0.3% respectively.
F.Shahidi, Dept. of Biochemistry, Memorial Univ. of Newfoundland, and C. Alasalvar, Dept. of Biological Sciences, Univ. of Lincoln, Brayford Pool, United Kingdom.
Local Research – Hazelnut Oil Composition and Comparisons
The quality of cold pressed hazelnut oil extracted from a mixture of Merville de Bollwiller, Ennis, and Butler hazelnuts grown at ‘The Nutt Ranch’ in Marlborough, was determined by measuring lipid classes, and fatty acids. The oil was tested at Hort. Research in Auckland during September of 2004. The reasons for having our oil tested were:
- To be able to give more accurate information about our own products to our customers.
- To make a comparison of the fresh hazelnut oil from our orchard, grown and pressed in Marlborough, with hazelnut oil from other parts of the world.
- To compare the fatty acids that make up hazelnut oil with virgin olive oil.
The total lipid content, by weight, of the hazelnuts being tested was 48.3%. This is slightly lower than the actual figure due to some oil loss within the extraction equipment. Seven fatty acids were identified by chromatography, among which oleic acid contributed 77.839% to the total, followed by linoleic, palmitic, and stearic acids. Unsaturated fatty acids accounted for 93.183% of the total fatty acids present. Saturated fatty acids made up only 6.817% of the total fatty acids and were composed of palmitic acid and stearic acid.
| Fatty Acid | Class | Hazelnut oil sample tested (oil %) | Comparison with virgin olive oil (oil %) | International norm for hazelnut oil (oil %) |
| 16:0 (palmitic acid) | Saturated | 4.614% | 10.930% | 4-9 |
| 16:1 (palmitoleic acid) | Unsaturated | 0.143% | 1.158% | Max 0.3 |
| 18:0 (stearic acid) | Saturated | 2.203% | 1.981% | 1-4 |
| 18:1 (oleic acid) (=Omega-9) | Unsaturated | 77.839% | 72.294% | 70-85 |
| 18:2 (linoleic acid (=Omega-6) | Unsaturated | 14.925% | 9.211% | 7-25 |
| 18:3 (linolenic acid) (=Omega-3) | Unsaturated | 0.143% | 0.793% | Max 0.6 |
| 20:1 (gadoleic acid) | Unsaturated | 0.133% | 0.313% | Max 0.3 |
Conclusion
We were extremely pleased with the results of our data as it shows good consistency with fatty acid measurements internationally. All of the different fatty acids were well within the international norms. The data gained, as well as the investigation of the makeup of our oil will help us in answering questions about the fatty acid content of our oil by interested customers in a more informed way. We found it very interesting that hazelnut oil compares extremely well with Olive oil, the best part, of course, being able to ingest the oil in the form of fresh hazelnuts or as cold pressed oil. We were amazed at the amount of research being done on Omega-3 fatty acid, Omega-6 fatty acid, and Omega-9 fatty acid internationally. The uses that our body makes of each of these are pretty incredible and it is notable that we can only get Omega-3 and Omega-6 within our diet. Our body is able to manufacture a limited amount of Omega-9 but most of what we need must still come from within our diet.
And finally, aside from the fact that hazelnut oil has super health giving properties, it also has a terrific aroma and taste. It is an excellent replacement for butter on potatoes and vegetables and is perfect for use in baking where an oil is called for.
DW & BL Null, Nutt Ranch Products, Marlborough, New Zealand