Identification of Geographical Origin of Milk by Amino Acid Profile Coupled with Chemometric Analysis

Table 1

Amino acid ratios (mean values ± SD, %) of milk samples from different regions.

Amino acids	Hebei	Inner Mongolia	Ningxia	Heilongjiang
Asp (%)	9.11 ± 0.24^b	7.80 ± 0.76^d	9.58 ± 0.21^a	8.50 ± 0.30^c
Glu (%)	22.78 ± 0.73^b	20.94 ± 1.61^c	23.83 ± 0.46^a	21.04 ± 0.94^c
His (%)	2.60 ± 0.24^a	2.67 ± 0.23^a	2.50 ± 0.19^b	2.17 ± 0.14^c
Ser (%)	5.66 ± 0.47^bc	5.82 ± 0.63^ab	5.95 ± 0.34^a	5.47 ± 0.52^c
Arg (%)	3.84 ± 0.38^a	3.52 ± 0.33^b	3.79 ± 0.43^a	3.53 ± 0.52^b
Gly (%)	1.96 ± 0.22^a	2.05 ± 0.27^a	1.73 ± 0.23^b	1.74 ± 0.20^b
Thr (%)	4.66 ± 0.32^a	4.66 ± 0.43^a	4.60 ± 0.10^ab	4.38 ± 0.42^b
Pro (%)	8.53 ± 0.62^b	10.31 ± 1.20^a	7.78 ± 0.32^c	8.17 ± 0.78^bc
Ala (%)	3.59 ± 0.11^b	3.15 ± 0.21^d	3.68 ± 0.09^a	3.47 ± 0.15^c
Val (%)	6.05 ± 0.24^b	6.59 ± 0.44^a	6.02 ± 0.17^bc	5.89 ± 0.21^c
Met (%)	2.11 ± 0.18^a	1.91 ± 0.23^b	2.13 ± 0.18^a	2.18 ± 0.14^a
Cys (%)	0.65 ± 0.07^d	0.81 ± 0.13^a	0.70 ± 0.08^c	0.74 ± 0.06^b
Ile (%)	4.75 ± 0.23^b	5.10 ± 0.32^a	4.73 ± 0.15^b	4.78 ± 0.19^b
Leu (%)	8.94 ± 0.24^b	10.12 ± 0.55^a	8.80 ± 0.27^bc	8.73 ± 0.25^c
Phe (%)	4.42 ± 0.21^ab	4.51 ± 0.31^a	4.46 ± 0.20^a	4.35 ± 0.15^b
Lys (%)	7.61 ± 1.69^b	6.58 ± 3.39^b	7.25 ± 1.37^b	10.32 ± 1.57^a
Tyr (%)	2.73 ± 0.94^bc	3.45 ± 2.24^b	2.47 ± 0.72^c	4.54 ± 1.43^a

Mean values in a row with different superscript letters are significantly different by post hoc Duncan’s test .