Application of near infrared (NIR) for analysis of food products

Introduction The near-infrared spectroscopy (NIR) is part of the electromagnetic spectrum with a wavelength range of 780 nm to 2500 nm. It propagates in simple harmonic motion specifically based on the chemical bonds and molecules present in the product. The frequency of vibrations appears in the NIR of the spectrum. They are specifically associated with overtones and fundamental vibrations. NIR spectroscopy is used for both qualitative and quantitative analysis of agriculture and food products. It requires minimal sample preparation and is non-destructive. Nir spectrometer is classified as a sequential instrument that is equipped with a monochromator or filter that collects the absorbance of samples sequentially, Fourier transforms, or multiplex instrument where the frequency is determined using interferogram and multichannel instruments where the absorbance of wavelengths are detected.

- Supreetha. S*

The spectral modes like reflectance, transmission, interacting, and transfectants of the NIR can be changed to determine the external and internal properties of the samples. The composition of products like moisture, protein, carbohydrate, fat, sugars, soluble solids and internal damages, bruises, adulteration, and several functional properties is determined.

Application for food analysis Milk and milk products

NIR spectroscopy plays a key role in the analysis and process control of milk and milk products. It is majorly used in the determination of moisture, fat, and lactose in liquid milk, whole milk powder (WMP), skim milk powder (SMP), whey powder, cream, butter, cheese, etc., majority of the milk-based products are emulsions which changes their physical characteristics during the preparation of samples. NIR can be effectively used in the online analysis of samples which reduces the sampling error by continuous instantaneous measurements. On-line analysis of milk powder helps in controlling the moisture content of the product. Fiber-optic probes are used as sensors for on- line quality determination due to the advantage over the absence of moving parts, robustness to high temperature and pressure, inertness, and ease of operation during clean in place procedure involving different acids and alkali. It is mainly used in on- line determination for moisture control of cheese especially cream cheese, cottage cheese, cheddar cheese, processed cheese, etc., It helps in obtaining uniform product quality in different batches.

Cereal and cereal products