Table 2.

Processing parameters and kibble traits of dog diets formulated with different carbohydrate sources

	Treatment1
Item	AG	GF	SEM	P-value
Raw material
Feed rate, kg/h	166	82	2.24	<0.0001
Preconditioner
Temperature, °C	91.6	71.8	2.56	<0.0001
Steam injection, kg/h	14.46	5.5	0.61	<0.0001
Water injection, kg/h	5.06	4.98	0.04	0.242
Extruder
Water injection, kg/h	12.68	12.04	0.36	0.189
Extruder screw speed, RPM	442	637	0.84	<0.0001
Knife speed, RPM	2,382	1,905	73.84	0.002
Motor load	49	41	0.55	<0.0001
Cone head pressure, PSI	460	188	16.59	<0.0001
Mass flow, kg/h	0.046	0.024	0.002	0.002
Bulk density, g/L	418	427	6.04	0.346
Other data
Specific mechanical energy, kJ/kg	115	141	7.37	0.038
In-barrel moisture %	30.3	38.2	0.54	<0.0001
Kibble traits
Bulk density, g/L	389	367	3.84	0.004
Weight, g	0.16	0.1	0.01	0.004
Piece density, g/cm3	0.6	0.54	0.01	0.009
Specific length, cm/g	4.41	4.24	0.08	0.174
Sectional expansion index	3.03	3.5	0.073	0.005
Hardness, kg	3.12	6.36	0.22	<0.0001
Toughness, kg * mm	2,427	1,778	220	0.070

¹AG = ancient grain; GF = grain-free.