Comparison of Viscoelastic Properties of Set and Stirred Yogurts Made from High Pressure and Thermally Treated Milks

Figures & data

FIGURE 1 Dynamic moduli and tan δ of stirred yogurts as a function of strain amplitude.

FIGURE 2 Dynamic moduli and tan δ of set yogurts as a function of strain amplitude.

TABLE 1 Regression coefficients and Duncan’s multiple range tests of strain dependent for G′, G″, and tanδ in set and stirred yogurts subjected to different treatments

	G′ = b0+ b1 *(γ–0.9)			G″ = b0+ b1 *(γ–0.9)			tanδ = A*exp(Bγ)
Regression models coefficients	b0	b1	R^2	b0	b1	R^2	A	B	R^2
Yogurt Treatment Stirred
HP 400	265.98^a	−30.71^a	0.97	83.07^a	−3.135^a	0.95	0.243^a	0.251^a	0.93
HP 300	227.46^b	−29.80^a	0.98	81.48^ab	−3.086^a	0.97	0.251^a	0.257^a	0.86
Heating	168.49^c	−28.34^a	0.97	75.75^b	−3.451^a	0.96	0.286^b	0.310^b	0.95
Control	157.58^c	−27.53^a	0.97	74.36^b	−3.342^a	0.96	0.282^b	0.330^b	0.95
Set
HP 400	860.92^a	−94.72^a	0.97	189.82^a	−10.92^a	0.98	0.211^a	0.105^a	0.91
HP 300	811.21^b	−95.23^a	0.99	174.09^ab	−10.58^a	0.98	0.218^a	0.108^a	0.89
Heating	732.17^c	−96.21^a	0.96	153.36^b	−9.97^a	0.97	0.232^b	0.127^b	0.90
Control	712.23^c	−96.56^a	0.96	148.26^b	−9.97^a	0.97	0.234^b	0.131^b	0.90

^abcMeans within columns for the same parameter having the same letter are not significantly different at P > 0.05.

TABLE 2 Regression coefficients and Duncan’s multiple range tests of frequency dependency for G′, G″, and tanδ in set and stirred yogurts subjected to different treatments

	G′ = mγ^n			G″ = mγ^n			tanδ = A + B*log(ω)
Regression models coefficients	M	n	R^2	m	n	R^2	A	B	R^2
Stirred yogurts
HP 400	151.92^a	0.203^a	0.97	31.49^a	0.233^a	0.95	0.378^a	−0.042^a	0.95
HP300	121.21^b	0.252^b	0.98	45.12^b	0.199^b	0.97	0.399^b	−0.044^a	0.92
Heating	75.22^c	0.281^c	0.97	53.39^c	0.147^c	0.96	0.447^c	−0.052^b	0.93
Control	70.24^c	0.285^c	0.97	52.55^c	0.142^c	0.96	0.447^c	−0.052^b	0.93
Set yogurts
HP 400	401.28^a	0.362^a	0.97	84.27^a	0.337^a	0.98	0.288^a	−0.045^a	0.93
HP 300	352.12^b	0.371^b	0.98	98.09^b	0.295^b	0.98	0.304^b	−0.046^a	0.92
Heating	255.13^c	0.401^c	0.97^a	104.06^c	0.279^c	0.97	0.354^c	−0.049^b	0.94
Control	235.32^c	0.393^c	0.97^a	108.24^c	0.271^c	0.97	0.349^c	−0.050^b	0.94

^abcMeans within columns for the same parameter having the same letter are not significantly different at p > 0.05.

FIGURE 3 Dynamic moduli and tan δ of stirred yogurts as a function of frequency.

TABLE 3 Regression coefficients and Duncan’s multiple range tests for time dependency of G′, G″, and tan δ in set and stirred yogurts subjected to different treatments

	G′ = A+B*log(t/tm)			G″ = A+B*log(t/tm)			tanδ = A+B*log(t/tm)
Regression models coefficients	A	B	R^2	A	B	R^2	A	B	R^2
Stirred Yogurts
HP 400	193.52^a	−20.13^a	0.96	66.64^a	−15.23^a	0.95	0.348^a	−0.053^a	0.97
HP300	154.69^b	−20.56^a	0.96	63.46^a	−14.53^a	0.97	0.402^b	0.050^a	0.99
Heating	102.34^c	−19.22^a	0.95	55.28^b	−14.14^a	0.96	0.546^c	0.052^a	0.94
Control	95.34^c	−19.01^a	0.95	52.34^b	−13.42^a	0.96	0.551^c	0.051^a	0.94
set yogurts
HP 400	1078.79^a	−51.22^a	0.99	277.68^a	−38.02^a	0.98	0.258^a	−0.026^a	0.95
HP 300	912.91^b	−50.21^a	0.98	273.04^a	−39.23^a	0.98	0.300^b	−0.027^a	0.97
Heating	734.67^c	−49.34^a	0.99	235.86^b	−39.89^a	0.97	0.323^c	0.028^a	0.98
Control	730.33^C	−48.55^a	0.99	230.32^b	−39.10^a	0.96	0.321^c	0.028^a	0.97

^abcMeans within columns for the same parameter having the same letter are not significantly different at p > 0.05.

FIGURE 4 Dynamic moduli and tan δ of stirred yogurts as a function of time.