Table 8
Free amino acids of seasonal Opuntia humifusa cladodes (unit: mg%)

	Spring	Summer	Winter
Aspartic acid	97.05±2.09^1)b2)	24.37±0.35^c	108.81±1.17^a
Glutamic acid	16.84±0.36^a	16.14±0.20^a	5.92±0.12^b
Asparagine	23.95±0.50^c	4.94±0.02^b	32.34±0.21^a
Serine	50.11±0.54^b	12.81±0.01^c	82.19±0.65^a
Glutamine	170.00±1.27^b	34.07±0.06^c	220.57±1.24^a
Histidine	5.71±0.21^b	1.95±0.29^c	8.14±0.11^a
Glycine	21.06±0.17^b	2.95±0.02^c	28.73±0.51^a
Threonine	57.06±0.28^a	13.06±0.05^c	46.27±0.90^b
Arginine	29.83±0.66^b	6.04±0.23^c	32.58±0.28^a
Alanine	50.32±0.60^b	11.62±0.07^c	58.55±0.46^a
Taurine	ND³⁾	ND	1.17±0.00
γ-aminobutyric acid	124.91±2.04^b	25.13±0.01^c	220.78±2.63^a
Tyrosine	37.70±0.66^b	7.75±0.12^c	41.92±0.41^a
Valine	52.77±1.01^b	20.18±0.04^c	73.86±0.20^a
Methionine	0.46±0.14^b	0.30±0.08^b	28.18±0.21^a
Tryptophane	7.12±0.89^b	2.81±0.15^c	30.34±0.41^a
Phenylalanine	45.88±1.16^b	12.31±0.10^c	55.83±0.70^a
Isoleucine	26.41±0.64^b	7.91±0.08^c	44.31±0.83^a
Leucine	77.22±1.52^b	15.31±0.21^c	84.70±0.49^a
Lysine	27.37±0.66^a	6.78±0.22^c	22.29±0.03^b
Proline	126.17±4.01^b	11.68±0.13^c	212.36±7.75^a
TAA⁴⁾	1,047.94	238.12	1,439.85
EAA⁵⁾	292.87	77.81	363.58
EAA/TAA(%)	27.95	32.68	25.25

All results are expressed as mean±SD for three replicates.
Different superscripts in the same row are significantly different at p<0.05 by Duncan’s multiple range test.
ND, Not detected.
Total free amino acid.
Total essential amino acid.