Question
I am a wildlife technician working on a research project on using the bioelectrical impedance to predicted fat mass in fish. We are know searching for availables methods to calculate fat mass in our samples. I wanted to understand how your Distell Fish Fatmeter works, what does it calculate to give the fat mass of a fish? Is it precise or really approximate, because we need really precise data?
Answer
Firstly… Principles of the Fatmeter…
The Fatmeter utilises low power microwave technology. The sensor transmits a microwave signal through the skin of the fish into the flesh. The microwave signal is attenuated by the amount of water present in the sample. Depth of penetration of the microwave signal is dependent upon the Water Content. In a healthy living organism there is this natural relationship between the amount of… Water, Fat & Total Body Solids. The main two variables are Fat and Water, with an inverse relationship between the two, with just a small change in the body solids (Protein, Minerals, Carbohydrate, fibre, etc). Using this relationship, we can create calibration algorithms to calculate the Fat Content of the sample. You can view the Science Publication on both Fish & Meat Fatmeters on our Website, under Product Information. Also on Website is details of AQIS Accreditation.
Secondly… Accuracy of Fatmeters….
My first reaction was that… as you are using bioelectrical impedance equipment to predict the fat mass in fish, then you should be going back to Chemical Laboratory Method for your comparative measurement. However, I realise that this can work out to be very expensive, especially if you intend to measure a large number of samples.
You can certainly use the Fish Fatmeter for your comparative measurement. Our Fatmeters are used around the world to measure Fat Content of Meat & Fish products. However, the main use of the Fish Fatmeter is to provide a rapid, non-destructive representative assessment of the fat content of … Whole Fish carcass, Trimmed Fish Fillets, Selected Sections, or directly on Fish Flesh. Our Meat Fatmeters are AQIS accredited to Chemical Lean (CL ) Standard. Overall… Distell’s Fish Fatmeter level of accuracy can be fairly stated, as that shown in the table below.
Accuracy of results
The accuracy of the FATMETER depends upon the fat/oil content of the sample being measured and ranges from an uncertainty in the fat content of (+/-) 1% (95% confidence interval) at low levels to (+/-) 4% at very high levels (greater than 45%). Therefore it is advisable that the operator follows the measurement methodology rigorously, and always takes readings as described in wall charts supplied.
Accuracy Guide
| Fat/Oil Reading |
Accuracy |
| 2 to 15% |
from.. ± 0.5%, rising to.. ± 1.0% ( 13 -15% at 14%) |
| 16 to 30% |
from.. ± 1.0%, rising to.. ± 2.0% (28-32% at 30%) |
| 31% and above |
from.. > ± 2%, rising to.. ± 4.0% (46-54% at 50%) |
The results gained will allow the operator to take swift decisions regarding feeding or processing of the fish species being measured.
Other methods currently in use for determining the lipid content of fish samples are destructive and slow, eg. In fish, a section or fillet of the fish is taken and analysed for fat/oil content by weighing, and using solvents to extract the fat, or, by driving off the water content by heating. These methods, unlike the DISTELL FATMETER, obviously cannot be used on LIVE fish.
If you do not wish to use direct chemical analysis of samples as your comparsion for every sample, then my recommendation would be to trial / evaluate the Fish Fatmeter by rental for a period of … ONE Month. This would allow you test Fatmeter performance, and also carry out some comparative laboratory analysis. The advantage of the Fish Fatmeter being that you can create a custom calibration setting for your specific product, based upon your own measurement data, and then program the Fatmeter accordingly. If you have many samples to measure then the Fatmeter would be very cost effective.
|
