HEAT AND MASS TRANSFER PROPERTIES OF PIZZA DURING BAKING

Figures & data

Figure 1. Heat and mass transfer mechanisms in scenario 1.

Figure 2. Pizza crust, tomato paste and cheese layers with the locations of nodes for finite difference equations.

Table 1. Heat Transfer Coefficients at Different Processing Conditions During Pizza Baking

Baking Conditions
Process	Temperature °C	H s	Velocity m/s	h rc W/(m^2 K)
Forced convection+Radiation baking	218	0.078	1	800
	204	0.072	1	785
	191	0.068	1	780
Natural convection+Radiation baking	218	0.078	0	780
	204	0.072	0	690
	191	0.068	0	675

H _s =surface humidity ratio.

H _a =ambient humidity ratio=0.08.

velocity=convective air velocity.

Table 2. Summary of Parameters Used in the Simulation for Two Banking Processes

Total pizza height, m	L=0.014
Latent heat of vaporisation, J/kg	L V =2256.9×10^3
Crust	Tomato paste	Cheese (Mozzarella)
Height, m	L p =0.01	L t =0.002	L c =0.002
Initial moisture content, db	m po =0.47 to 0.55	m t0 =3.73	m c0 =0.826
Density, kg/m^3	ρ p =862	ρ t =1073	ρ c =1140
Specific heat, J/(kg K)	c pp =3770	c pt =2930	C pc =2864
Thermal diffusivity, m^2/s	α p =0.128 × 10^−6	α t =1.737 × 10^−7	α c =1.164 × 10^−7
Thermal conductivity, W/(m K)	K p =0.416	K t =0.546	K c =0.380

Table 3. Moisture Diffusivities and Surface Mass Transfer Coefficient During Pizza Baking

Moisture Diffusivity, m^2/s			RMS Moisture, db/T(°C)
Temperature(°C)	Crust	Tomato		Cheese	Mass Transfer Coefficient, kg/(m^2 s)
Forced convection+radiation baking	218	0.15×10^−8	0.29×10^−9	0.70×10^−10	1.28	0.042/1.37
	204	0.13×10^−8	0.28×10^−9	0.70×10^−10	1.22	0.047/1.82
	191	0.12×10^−8	0.27×10^−9	0.70×10^−10	1.07	0.019/2.73
Natural convection+ radiation baking	218	0.62×10^−9	0.15×10^−10	0.70×10^−10	1.21	0.021/1.81
	204	0.60×10^−9	0.14×10^−10	0.70×10^−10	1.06	0.052/4.36
	191	0.59×10^−9	0.13×10^−10	0.70×10^−10	1.00	0.035/4.81

RMS=root mean square of deviations between experimental and predicted moisture histories.

Figure 3. Observed and predicted temperature histories of pizza crust at different oven temperatures during forced convection baking.

Figure 4. Observed and predicted temperature histories of pizza crust at different oven temperatures during natural convection baking.

Figure 5. Observed and predicted moisture histories of pizza crust at different oven temperatures during forced convection baking.