Cereal Chem 64:418-422   |  VIEW ARTICLE

Analysis of Protein in Ground and Whole Field Peas by Near-Infrared Reflectance.

R. Tkachuk, F. D. Kuzina, and R. D. Reichert. Copyright 1987 by the American Association of Cereal Chemists, Inc. 

Protein content of ground and whole field peas (Pisum sativum L. cv. Trapper) was determined by near- infrared reflectance spectroscopy. Optimal wavelengths for prediction of protein were selected using a stepwise multiple linear regression program. Five mathematical treatments of log (1/R) data (smoothed, first derivative, second derivative, lamda x - lamda y, and [lambda x - lambda y]/lambda y) were investigated. Calibration equations developed for each of these parameters were used to predict protein content in an independent set of pea samples. Protein content was predicted more accurately in ground than in whole field peas for all data treatments examined. For ground field peas, the calibration equation developed from smoothed data and incorporating four wavelengths (2,162, 2,126, 1,774, and 2,292 nm) gave a multiple correlation coefficient (R) of 0.996 and a standard error of estimate of 0.34%. Protein prediction for whole field peas was much poorer when smoothed data was analyzed (R = 0.919, standard error of estimate = 1.34%), but improved noticeably when first derivative data was used for calibration.