Effect of Temperature and Concentration on the Density of Clarified Pineapple Juice

Figures & data

Table 1 Physical and chemical characteristics of depectinised and clarified pineapple juice concentrate

pH	4.86
Acidity (g/l citric acid)	13.7
Soluble solids (°Brix)	64.1
Total moisture content (%)	33.2
Formol index (ml 0.1 N NaOH/100 ml)	37
Glucose (g/l)	135.23
Fructose (g/l)	127.85
Sucrose (g/l)	361.92

Table 2 Experimental values for density (in g/cm³) at different concentration and temperature for a depectinised and clarified pineapple juice

	Density (g/cm^3)
Temperature (°C)	64.1 Brix	60 Brix	50 Brix	40 Brix	30 Brix	20 Brix	10 Brix
10	1.320	1.296	1.240	1.185	1.135	1.086	1.042
20	1.317	1.292	1.237	1.181	1.132	1.085	1.040
30	1.307	1.285	1.233	1.177	1.129	1.081	1.036
40	1.301	1.279	1.228	1.172	1.125	1.077	1.033
50	1.294	1.272	1.222	1.167	1.120	1.072	1.028
60	1.285	1.264	1.215	1.160	1.113	1.066	1.022
70	1.277	1.256	1.208	1.153	1.107	1.060	1.017

Figure 1 Density of depectinised and clarified pineapple juice at different soluble solids content as a function of temperature, together with the linear fitting.

Figure 2 Density of depectinised and clarified pineapple juice at different temperatures as a function of concentration, together with the linear fitting.

Table 3 Fitting parameters for equations to predict the variation of density of depectinised and clarified pineapple juice with temperature and soluble solids concentration

Equation model	A	−b·10^4	c·10^3	d·10^6	R^2
ρ = a + bT + cC + dC ^2	1.010±0.004	5.41±0.9	4.1±0.2	11±3	0.9982
ρ = (a + bT)exp(cC + dC ^2)	1.006±0.003	4.6±0.3	4.3±0.1	0.4±2.1	0.9988
ρ = (a + cC + dC ^2)exp(bT)	1.007±0.003	4.7±0.3	4.2±0.1	12±3	0.9988
ρ = a exp(bT + cC + dC ^2)	1.006±0.003	4.7±0.3	4.3±0.1	0.4±2.1	0.9988

Figure 3 Combined effect of temperature and soluble solids content on density of pineapple juice represented as a response surface, as predicted by Eq. (9).