Analysis of nutrients of lupines by near-infrared reflectance spectroscopy (NIRS)

• Christiane Jatsch
• A. Sundrum
• P. Tillmann

The project was supported by the federal Ministry of food, Agriculture and Consumer Protection.

The ban on feeding animal meal has given lupin greater importance as a protein supplement feed. In order to achieve a targeted use in ration design, sound knowledge of the nutrient composition is required.
In recent years, near-infrared reflectance spectroscopy (NIRS) has established itself as a reliable analytical method. This method has its advantages in the greatly reduced analysis time, the simultaneous investigation of several raw nutrients, the avoidance of environmental pollution by chemicals and the associated lower operating costs.
The aim of the project was to develop a calibration for the individual raw nutrients of the various botanical species of lupin.

For the development of the NIRS calibration a broad sample base is necessary. After intensive efforts at seed breeding companies, chambers of agriculture, organic farming associations and agricultural institutes, the targeted number of samples of 50 blue (Fig.1), yellow and white lupins each for the reference analysis could be achieved. The lupin samples analyzed came from the cultivation years 2000 - 2003 from 29 different locations and cover 24 different varieties.
The lupin samples used were analyzed for dry matter (DM), crude ash (XA), crude protein (XP), crude fat (XL), and crude fiber (XF) using the appropriate methods of the Weender Root Nutrient Analysis (VDLUFA, 1997). Starch was determined polarimetrically according to the method of Ewers. Total sugars were analyzed according to the inversion-reduction method of Luff-Schoorl.
A NIRS instrument (FOSS 6500) and rectangular cells (window 56*47 mm) were used to record the spectra. WinISI, version 1.04 software was used to generate a calibration equation.
For the calibration the wave range 1108-2500 nm was chosen, for the spectral transformation the option "SNV and detrend" from the ISI software and for the mathematical data transformation the common variant 2,4,4,1.
40 lupine samples of each of the 3 botanical species were introduced for the calibration set and 10 samples in each of the validation set. The calibration was developed by relating the samples from the reference analysis to the NIRS spectra via multiple linear regression. The calculations resulted in a regression equation that was used to perform cross-validation.

• FOSS (1999): ISI Windows Near-Infrared Softwae. The Complete Software Solution for Routine-Analysis, Robust Calibrations and Networking. animals.
• VDLUFA (1997): Method book III. the chemical analysis of feed. VDLUFA-Verlag, Darmstadt

The project was funded by the Federal Ministry of Consumer Protection, Food and Agriculture via the Federal Agency for Agriculture and Food (BLE), Food and Agriculture via the Federal Agency for Agriculture and Food (BLE).

• Christiane Jatsch
• A. Sundrum
• P. Tillmann