Differentiation of Organic Cocoa Beans and Conventional Ones by Using Handheld NIR Spectroscopy and Multivariate Classification Techniques

Table 2

NIR wavelength band assignments.

Wavelength (nm)	Functional group	Band assignments
958	OH	O-H 2^nd overtone stretch of carbohydrate [54]
973, 1005	NH3	N-H 2^nd overtone stretch associated with fat (Chu [53])
986	O-H	O-H 1^st and 2^nd overtones stretch of absorption peak of starch [54]
1200	C-H	C-H 1^st overtones stretch related to proteins and starch [50]
1280	C-H	C-H 1^st overtone bond stretching corresponding to fats and aromatic compounds [52]
1483	O-H	O-H 2^nd overtone stretch corresponding moisture (Zhang et al. [53])
1417	O-H	H2O band groups corresponding to weakly bounded water and aromatic compounds [43]
1440, 1460	O-H	O-H stretch 1st overtone of starch, water band, and sugars ([13]; Zhang et al. [46])
1608	C=O	C-O from COOH typical of amines and acidity [55]