Estimation of Alanine and Glycine in Cane Juice Using Near Infrared Spectroscopy

The ICUMSA or AOAC (Association of Official Agricultural Chemists) traditional test methods for testing individual constituents, pol and brix, are time consuming, operator dependent and involve the use of hazardous chemicals. The increased awareness of environmental and health topics makes it desirable to avoid the clarification of cane juice with basic lead acetate. Widely used in the food and agricultural industries, Near Infrared Spectroscopy NIR has now made considerable inroads into the more lengthy and wet chemistry procedures. Near Infrared is the region of combination bands and overtones due to interatomic forces. Hydrogenic atoms being the lightest vibrate within the near infrared region due to N-H, O-H and C-H groups. These are common atoms present within most food products. As near infrared wavelengths are specific, individual components can be identified so it can be used for quantitative analysis of phosphates, silicates and amino acids in cane juice. Amino acids are important as they, along with other nitrogenous bodies, react with reducing sugars to form colored compounds. Analyzing amino acids in a sample can help solve color problem in sugar. Alanine and glycine are commonly found amino acids in sugarcane. In the present research the online estimation of alanine and glycine is done in cane juice using Near-Infrared spectroscopy. Near Infrared Spectrophotometer of Elico (India) range (600-2500nm) has been used in its transmittance mode in conjunction with two multivariate calibration procedures, i.e., Partial Least Square Regression analysis (PLSR) and Stepwise Multivariate Linear Regression analysis (SMLR) for the analysis of alanine and glycine in cane juice. Multi linear regression analysis was also carried out to find out the most correlating wavelengths along with the standard deviation.