Table 2. Change of free amino acids after fermentation with and without peptide supplementation

Amino acids	FAA contents before fermentation (mg kg^–1)			FAA contents after fermentation (mg kg^–1)
Amino acids	FM	NPMP_20%	FPMP_20%	FM	NPMP_20%	FPMP_20%
Aspartic acid	0.03±0.01^a	0.03±0.01^a	0.70±0.05^c	0.35±0.04^b	0.74±0.05^c	3.15±0.2^d
Threonine	0.13±0.02^a	0.14±0.02^a	1.21±0.05^c	0.21±0.03^b	1.78±0.13^d	3.06±0.12^e
Serine	0.12±0.03^a	0.12±0.02^a	0.71±0.06 ^b	1.42±0.12^c	1.81±0.11^d	2.31±0.15^e
Glutamic acid	0.14±0.03^a	0.15±0.03^a	0.52±0.03^b	1.76±0.11^c	13.31±0.25^d	15.14±0.3^e
Proline	0.28±0.03^a	0.27±0.03^a	1.13±0.03^b	13.98±0.35^c	27.34±0.64^d	36.22±0.82^e
Glycine	0.14±0.02^a	0.14±0.03^a	0.33±0.02^b	0.71±0.04^c	1.53±0.05^d	2.95±0.08^e
Alanine	0.36±0.04^a	0.34±0.05^a	2.14±0.07^b	3.21±0.09^c	10.79±0.55^d	14.26±0.86^e
Cystine	0.45±0.02^b	0.46±0.03^b	2.61±0.08^c	0.35±0.03^a	2.51±0.21^c	2.57±0.06^c
Valine	1.36±0.06^a	1.32±0.04^a	4.31±0.12^b	15.19±0.43^c	33.31±0.68^d	39.84±0.86^e
Methionine	0.02±0.01^a	0.04±0.01^b	11.16±0.32^d	0.04±0.02^b	2.19±0.24^c	11.73±0.42^e
Isoleucine	0.64±0.06^a	0.63±0.07^a	3.18±0.26^b	12.61±0.7^c	19.02±0.85^d	31.62±0.98^e
Leucine	0.12±0.02^a	0.41±0.02^b	22.83±0.82^d	6.46±0.48^c	50.28±1.13^e	131.17±2.4^f
Tyrosine	0.62±0.06^b	0.59±0.07^b	3.41±0.23^c	0.49±0.05^a	16.62±0.35^d	35.87±1.5^e
Phenylalanine	0.27±0.01^b	0.25±0.02^b	2.58±0.21^c	0.22±0.01^a	15.57±0.57^d	32.24±1.25^e
Lysine	0.06±0.01^a	0.12±0.02^b	6.62±0.32^d	1.69±0.42^c	23.05±0.89^e	32.83±2.6^f
Histidine	2.03±0.14^a	1.98±0.22^a	4.42±0.34^b	2.16±0.24^a	5.03±0.56^c	11.02±0.81^d
Arginine	0.78±0.07^a	0.80±0.08^a	1.04±0.12^b	1.63±0.15^c	1.46±0.13^c	3.98±0.32^d
Total amino acids	7.55±0.28^a	7.79±0.33^a	68.90±0.96^c	62.48±0.84^b	226.34±2.25^d	409.96±3.18^e

The starter strain was Lacticaseibacillus casei 01.
All values are mean±SD (n=3).
Different superscript letters in the same row indicate significant differences between different samples at p<0.05.
FAA, free amino acid; FM, fermented milk without supplementation; NPMP_20%, fermented milk containing 20% NPMP; FPMP_20%, fermented milk containing 20% FPMP.