Table 4. The changes in pH of stirred yoghurts fortified with tomato peel powder (TPP) during refrigerated (4°C±2°C) storage

Storage period (d)	Level of tomato peel powder
	Before fermentation					After fermentation
	0%	2%	4%	6%	8%	0%	2%	4%	6%	8%
1	4.46±0.03^Ap	4.15±0.02^Aq	4.77±0.02^Ar	4.89±0.02^As	5.15±0.02^At	4.46±0.01^Ap	4.12±0.01^Aq	4.34±0.01^Ar	4.39±0.02^As	4.50±0.02^At
7	4.32±0.02^Bp	4.05±0.01^Bq	4.72±0.03^Ar	4.84±0.04^Bs	5.05±0.03^Bt	4.32±0.02^Bp	4.09±0.01^ABq	4.23±0.02^Br	4.30±0.01^Br	4.40±0.01^Bs
14	4.31±0.03^Bp	4.01±0.02^BCq	4.65±0.02^Br	4.78±0.02^Cs	4.99±0.01^Bt	4.31±0.03^Bpq	4.08±0.01^BCs	4.16±0.03^Br	4.23±0.02^Cqr	4.32±0.01^Cp
21	4.22±0.02^Cp	3.99±0.03^Cq	4.55±0.03^Cr	4.68±0.03^Ds	4.86±0.04^Ct	4.22±0.02^Cp	4.04±0.02^Cq	4.06±0.02^Cq	4.15±0.01^Dp	4.22±0.01^Dp

Data represented as mean±SD (n=3).
Mean values with different upper case letters in the same column are significantly different at p<0.05.
Mean values with different lower case letters in the same row (within one incubation type) are significantly different at p<0.05.