Determining the contents of protein and amino acids in peanuts using near-infrared reflectance spectroscopy

Background: The protein and amino acid contents of peanuts play a key role in determining their quality and value. Therefore, accurate, nondestructive, quick, and automated measurement of these components would be valuable in a commercial environment. This study explored the feasibility of determining the contents of protein and amino acids in peanuts using near infrared-reflectance spectroscopy (NIRS).

Results: 141 peanut samples were collected from 12 provinces in China. The spectra were scanned and obtained with an NIRS system. The determination coefficient and the ratio of the standard deviation in the validation set to the standard error of validation corresponded to 0.99 and 6.53 for protein, 0.88 and 2.52 for Asp, 0.83 and 3.00 for Thr, 0.86 and 2.40 for Ser, 0.87 and 2.57 for Glu, 0.88 and 2.36 for Gly, 0.88 and 3.00 for Leu, 0.89 and 2.88 for Arg, and 0.96 and 7.50 for Cys.

Conclusions: NIRS combined with multivariate calibration has significant potential in determining the protein and amino acid contents of peanuts. This method is suitable for use in an industrial setting owing to its ease of use as well as the relatively low cost of obtaining and running the necessary equipment.