Effect of species on the distribution and oxidative stability of milk added of lead and cadmium

Figures & data

Table 1. The pH value and chemical properties (g/100 g) of cow, buffalo and goat milk.

	Cow		Buffalo		Goat
	Mean	SD1	Mean	SD	Mean	SD
pH	6.60^a	0.01	6.72^b	0.02	6.52^c	0.06
Fat	3.94^a	0.01	5.80^b	0.11	3.20^c	0.09
Protein	3.39^a	0.11	4.36^b	0.12	3.15^c	0.05
casein	2.42^a	0.18	3.26^b	0.32	2.15^c	0.13
Lactose	4.64^a	0.1	4.52^b	0.09	4.01^c	0.10
Ash	0.80^a	0.06	0.80^a	0.06	0.83^a	0.04
Total solids	12.78^a	0.31	15.07^b	0.70	11.20^c	0.12

¹ SD: standard deviation;.

^a,b,c Means within a row with different superscripts differ (p < 0.01).

Table 2. Distribution of added Cd and Pb in the milk fractions (fat, casein, and whey), regardless of the analysed species.

	% Pb	% Cd
Skimmed milk	96.74	94.21
Fat	3.26	5.79
Enzymatic coagulation (Skimmed milk)
Casein	94.77	90.54
Whey	1.97	3.67
Skimmed milk	96.74	94.21
Fat	3.26	5.79
Enzymatic coagulation (Skimmed milk)
Casein	94.77	90.54
Whey	1.97	3.67

Figure 1. Percentage distribution of Cd and Pb in casein and fat fractions regardless of species.

Table 3. Oxidative status of control, Cd and Pb-milk.

	Control		Cd		Pb
	Mean	SD^d	Mean	SD	Mean	SD
MDA^e (µg/g of milk)	0.198^a	0.016	0.253^b	0.015	0.299^c	0.025
Dithyrosines (µM)	60.09^a	14.48	76.92^b	8.21	79.45^b	7.54
AOPPs (mM)	1.53^a	0.22	2.19^b	0.24	2.41^b	0.29
Thiols (µM)	392.14^c	24.99	310.34^a	20.17	330.83^b	14.00

^a,b,c Means within a row with different superscripts differ (p < 0.05).

^d SD: standard deviation;

^e MDA: malondialdehyde.

Table 4. MDA content (ng/g of milk) in control, Cd- and Pb-milk of cow, goat and buffalo.

	Cow		Goat		Buffalo
	Mean	SD1	Mean	SD	Mean	SD
Control	0.195^a	0.025	0.193^a	0.008	0.205^a	0.016
Cd	0.267^b	0.007	0.236^c	0.007	0.257^c	0.007
Pb	0.323^d	0.011	0.272^e	0.016	0.302^f	0.015

¹ SD: standard deviation;.

^a,.f Means within a column and row with different superscripts differ (p < 0.05).

Table 5. Content in dithyrosines and advanced protein products for oxidation (AOPPS) of control and contaminated milk, distinctly by species.

	Dithyrosines (µM)
	Cow		Buffalo		Goat
	Mean	SD1	Mean	SD	Mean	SD
Control	72.51^a,A	5.35	66.03^a,B	3.32	42.01^a,C	2.16
Cd	90.02^b,A	3.27	80.96^b,B	4.12	50.68^b,C	3.91
Pb	94.41^c,A	5.27	83.35^c,B	6.23	52.95^b,C	4.36
	AOPPs (mM)
Control	1.72^a,A	0.1	1.61^a,B	0.03	1.25^a,C	0.076
Cd	2.49^b,A	0.02	2.15^b,B	0.02	1.61^b,C	0.08
Pb	2.66^c,A	0.07	2.52^c,B	0.08	1.84^c,C	0.08

¹ SD: standard deviation;.

^a,b,c Means within a column with different superscripts differ (p < 0.05).

^A,B,C Means within a row with different superscripts differ (p < 0.05).

Table 6. Content in free thiol groups (µM/L) in control and contaminated milk, distinctly by species.

		Free thiol group (µM/L)
	Cow		Buffalo		Goat
	Mean	SD^j	Mean	SD	Mean	SD
Control	334.86^a	7.06	457.92^b	15.37	384.23^c	17.37
Cd	266.9^d	11.61	357.18^e	11.99	307.23^f	6.39
Pb	288.9^g	10.99	362.67^h	12.17	341.24^i	5.98

^{a,b,c,d,e,f,g,h,i} Means within a column and row with different superscripts differ (p < 0.01).

^j SD: standard deviation.

Data availability statement

The data that support the findings of this study are available from the corresponding author, upon reasonable request.