In vitro immuno-modulatory ability of tryptic caseinate hydrolysate affected by prior caseinate glycation using the Maillard reaction or transglutaminase

Figures & data

Table 1. Saccharide and 10 amino acid contents (g/kg protein) of the tryptic hydrolysates from caseinate, GC-I, and GC-II.

Indices	Tryptic hydrolysates			Indices	Tryptic hydrolysates
	Caseinate	GC-I	GC-II		Caseinate	GC-I	GC-II
Glucosamine	ND	ND	5.7	Met	32.9	37.6	48.5
Lactose	ND	10.6	ND	Phe	61.2	58.8	61.2
Cys	7.1	7.1	7.7	Thr	47.1	42.4	43.4
His	32.9	28.2	30.6	Lys	89.4	77.6	84.2
Leu	101.2	96.5	96.9	Tyr	63.5	58.8	61.2
Ile	61.2	56.5	56.1	Val	70.6	68.2	71.4

Note: GC-I is glycated caseinates prepared from caseinate and lactose via the Maillard reaction, while GC-II is glycated caseinate prepared from caseinate and oligochitosan via TGase catalysis. ND, not detectable.

Table 2. Effects of the tryptic hydrolysates of caseinate, GC-I, and GC-II at three doses on three immune cells.

Hydrolysate samples	Doses (μg/mL)	Lymphocyte proliferation		Macrophage phagocytosis		NK cell activity
		24 h	48 h	24 h	48 h	24 h	48 h
Caseinate hydrolysate	25	1.257 ± 0.016^b	1.293 ± 0.015^b	1.133 ± 0.014^b	1.224 ± 0.010^b	31.5 ± 2.3^b	37.3 ± 1.8^b
	50	1.314 ± 0.012^d	1.349 ± 0.011^c	1.226 ± 0.019^e	1.302 ± 0.014^c	38.3 ± 2.2^de	44.9 ± 1.9^de
	100	1.402 ± 0.019^f	1.496 ± 0.012^e	1.380 ± 0.012^h	1.480 ± 0.017^e	45.1 ± 2.3^f	53.8 ± 2.8^g
GC-I hydrolysate	25	1.193 ± 0.012^a	1.224 ± 0.016^a	1.079 ± 0.014^a	1.145 ± 0.019^a	25.7 ± 1.7^a	30.0 ± 2.1^a
	50	1.251 ± 0.012^b	1.281 ± 0.012^b	1.207 ± 0.019^d	1.275 ± 0.015^c	32.7 ± 2.9^bc	38.6 ± 2.1^bc
	100	1.309 ± 0.019^d	1.334 ± 0.015^c	1.310 ± 0.012^g	1.401 ± 0.017^de	41.4 ± 2.1^ef	48.4 ± 2.5^ef
GC-II hydrolysate	25	1.293 ± 0.012^c	1.337 ± 0.014^c	1.189 ± 0.011^c	1.280 ± 0.016^c	35.8 ± 2.5^cd	41.7 ± 1.8^cd
	50	1.365 ± 0.015^e	1.406 ± 0.012^d	1.267 ± 0.019^f	1.370 ± 0.019^d	42.2 ± 2.3^ef	49.5 ± 2.6^f
	100	1.456 ± 0.016^g	1.520 ± 0.014^f	1.477 ± 0.019^i	1.565 ± 0.018^f	52.9 ± 2.1^g	58.4 ± 1.9^h

Note: GC-I is glycated caseinates prepared from caseinate and lactose via the Maillard reaction, while GC-II is glycated caseinate prepared from caseinate and oligochitosan via TGase catalysis. Different lowercase letters after the values as the superscripts in same column indicate that one-way ANOVA of the mean values is different significantly (P < .05).

Table 3. Effects of the tryptic hydrolysates of caseinate, GC-I, and GC-II on the secretion of three cytokines in splenocytes.

Hydrolysate samples	Doses (μg/mL)	IL-2 (pg/mL)		IL-4 (pg/mL)		IFN-γ (pg/mL)
		24 h	48 h	24 h	48 h	24 h	48 h
Caseinate hydrolysate	25	42.3 ± 1.6^b	48.6 ± 1.4^b	25.6 ± 1.5^cd	23.3 ± 1.2^e	30.0 ± 1.5^b	37.4 ± 1.6^b
	50	47.6 ± 1.2^c	52.6 ± 1.2^c	23.9 ± 1.6^c	21.9 ± 1.3^de	39.6 ± 1.1^d	43.1 ± 1.2^c
	100	52.2 ± 1.8^d	57.2 ± 1.1^d	20.1 ± 1.1^ab	18.5 ± 1.2^ab	46.8 ± 1.8^f	51.6 ± 1.8^e
GC-I hydrolysate	25	38.9 ± 1.1^a	45.3 ± 1.6^a	28.2 ± 1.6^e	26.4 ± 1.1^f	26.9 ± 1.1^a	32.7 ± 1.1^a
	50	42.6 ± 2.1^b	48.5 ± 1.5^b	26.9 ± 1.1^de	23.6 ± 1.3^e	35.5 ± 1.6^c	39.8 ± 1.6^b
	100	47.3 ± 1.6^c	52.0 ± 1.4^c	24.1 ± 1.2^c	20.1 ± 1.1^bcd	42.4 ± 1.8^e	47.5 ± 1.5^d
GC-II hydrolysate	25	46.5 ± 1.6^c	50.4 ± 1.1^bc	23.8 ± 1.1^c	20.9 ± 1.5^cd	38.6 ± 1.6^d	43.9 ± 1.4^c
	50	51.4 ± 1.1^d	56.1 ± 1.7^d	21.4 ± 1.6^b	18.9 ± 1.1^abc	42.8 ± 1.4^e	50.8 ± 1.8^e
	100	56.6 ± 1.8^f	60.2 ± 1.5^e	18.1 ± 1.4^a	16.7 ± 1.4^a	50.9 ± 1.8^g	58.4 ± 1.4^f

Note: GC-I is glycated caseinates prepared from caseinate and lactose via the Maillard reaction, while GC-II is glycated caseinate prepared from caseinate and oligochitosan via TGase catalysis. Different lowercase letters after the values as the superscripts in same row indicate that one-way ANOVA of the mean values is different significantly (P < .05).

Table 4. Effects of the tryptic hydrolysates of caseinate, GC-I, and GC-II on the secretion of five cytokines in RAW 264.7 murine macrophages.

Hydrolysate samples	Doses (μg/mL)	IL-1β (pg/mL)		IL-6 (pg/mL)		TNF-α (pg/mL)		iNOS (pg/mL)		LZM (ng/mL)
		24 h	48 h	24 h	48 h	24 h	48 h	24 h	48 h	24 h	48 h
Caseinate hydrolysate	25	77.1 ± 1.1^ab	87.6 ± 1.6^b	25.2 ± 1.3^a	29.9 ± 1.1^ab	39.2 ± 1.4^b	55.6 ± 1.3^b	138.5 ± 2.1^b	167.2 ± 2.9^b	15.6 ± 1.1^b	22.1 ± 1.3^b
	50	92.3 ± 3.1^d	104.8 ± 2.1^d	31.3 ± 1.5^c	36.4 ± 1.4^d	78.4 ± 1.1^e	99.7 ± 1.6^e	218.6 ± 4.3^d	282.8 ± 3.8^e	22.1 ± 0.9^c	25.2 ± 2.1^c
	100	108.4 ± 2.2^f	116.5 ± 2.8^f	38.2 ± 1.2^e	45.6 ± 1.9^g	102.9 ± 1.8^g	128.0 ± 1.9^h	329.9 ± 7.5^g	426.9 ± 4.1^h	28.6 ± 1.6^e	31.1 ± 1.6^e
GC-I hydrolysate	25	73.8 ± 1.6^a	82.9 ± 1.2^a	23.6 ± 0.9^a	27.7 ± 1.2^a	30.1 ± 1.5^a	47.1 ± 0.9^a	106.9 ± 2.2^a	124.9 ± 2.1^a	12.1 ± 0.9^a	18.5 ± 1.2^a
	50	82.9 ± 2.1^bc	95.3 ± 1.6^c	28.9 ± 1.1^b	33.5 ± 1.3^c	59.2 ± 1.4^d	75.8 ± 1.3^d	179.6 ± 4.1^c	234.8 ± 3.9^d	16.9 ± 1.1^b	20.5 ± 1.3^ab
	100	102.4 ± 2.8^e	108.9 ± 2.1^e	34.8 ± 1.4^d	42.5 ± 1.4^f	89.4 ± 1.3^f	105.8 ± 1.5^f	261.3 ± 5.6^e	374.2 ± 4.1^g	23.2 ± 1.2^c	25.9 ± 1.4^cd
GC-II hydrolysate	25	84.8 ± 2.2^c	92.6 ± 2.1^c	27.6 ± 1.2^b	31.6 ± 1.1^bc	46.8 ± 1.2^c	69.6 ± 1.2^c	179.3 ± 3.9^c	209.5 ± 2.1^c	22.6 ± 1.1^c	26.9 ± 1.5^cd
	50	99.4 ± 2.1^e	105.9 ± 2.6^de	32.8 ± 1.4^cd	39.9 ± 1.3^e	92.1 ± 1.6^f	111.5 ± 1.4^g	269.9 ± 5.8^f	311.5 ± 2.6^f	25.9 ± 1.2^d	28.5 ± 1.3^de
	100	116.2 ± 2.8^f	123.7 ± 3.1^g	44.2 ± 1.5^f	49.6 ± 1.2^h	121.2 ± 1.9^h	142.8 ± 2.1^i	363.1 ± 6.4^h	449.2 ± 5.3^i	32.8 ± 1.3^f	36.2 ± 1.9^f

Note: GC-I is glycated caseinates prepared from caseinate and lactose via the Maillard reaction, while GC-II is glycated caseinate prepared from caseinate and oligochitosan via TGase catalysis. Different lowercase letters after the values as the superscripts in same row indicate that one-way ANOVA of the mean values is different significantly (P < .05).