NIR Interactance And The Human Body Analysis

Near infrared interactance is a process that has long been used in the food industry to measure the fat contents of meat. However, lately, it has become more and more popularly used to measure the content of the human body. But is near infrared interactance really that reliable for human body analysis?

In meat analysis, light absorption and reflection utilizing near infrared spectrometry is conducted to analyze the composition of the meat being examined in a near infrared interactance process. Infrared light at frequencies of 938nm and 948nm are emitted through the inner fat and muscle tissues. Fat absorbs the light; while lean meat reflects it. By comparing the ratio between absorbed light and reflected light, we can determine the volumes of both the fat and muscle tissues.

Then, with the use of a UV VIS NIR spectrophotometer, we can measure the direct transmissivity of the fats in the meat. Since a UV VIS NIR spectrophotometer is used to measure the radiometric properties of tra nsparent and opaque materials in the solar and in the long infra-red wavelength range, radiometric properties of can be measured and evaluated.

By measuring the transmisivity of the fats in the meat, we can determine if the water content of the meat and determine how fresh it is. The UV VIS NIR spectrophotometer, however, does not form part of the near infrared interactance process; but it may be used as a valid support to the use of a near infrared spectrometry machine in the near infrared interactance process.

Since the process of near infrared interactance is quick and non-evasive; and since UV VIS NIR spectrophotometers and near infrared spectrometry machines (used in the near infrared interactance process) are easy to use and understand, this may seem perfect for analyzing the fat and muscle content of the human body. However, near infrared interactance has proven to be quite unreliable with an error margin of about 5%. This is not a favorable error margin when examining human beings.

At this point in time, the process of near infrared interactance still has a long way to go before it can be used accurately on the human body.