Table 5 Regression equations of ice cream stored at –18℃, –6℃, –1℃, and 4℃

Characteristics indicator		Temperature (T)	Reaction order	Regression equation	Ea (kal/mol)1)	K2)	A03)-At4)	Shelf-life (month)
I1	Total aerobic counts (CFU/mL)	255	Zero	LnK=–19025x+66.498	37.80	0.0003	4.00	433.61
		267				0.0086	4.00	15.51
		272				0.0319	4.00	4.19
		277				0.1126	4.00	1.18
	pH	255	Zero	LnK=–6566.8x+18.456	13.05	0.0007	0.49	24.27
		267				0.0022	0.27	4.17
		272				0.0034	0.10	0.98
		277				0.0052	0.30	1.88
	Sensory	255	Zero	LnK=–26860x+96.878	53.37	0.0002	4.00	626.68
		267				0.0242	4.00	5.51
		272				0.1538	4.00	0.87
		277				0.9144	4.00	0.15
I2	Total aerobic counts (CFU/mL)	255	Zero	LnK=–9664.8x+32.428	19.20	0.0042	3.52	27.98
		267				0.0231	3.52	5.09
		272				0.0449	3.52	2.62
		277				0.0852	3.52	1.38
	pH	255	First	LnK=–10770x+33.175	21.40	–9.0603	0.13	36.32
		267				–7.1621	0.05	2.29
		272				–6.4206	0.02	0.39
		277				–5.7059	0.04	0.44
	Sensory	255	First	LnK=–18664x+64.971	37.09	–8.2212	0.59	72.86
		267				–4.9316	0.59	2.72
		272				–3.6467	0.59	0.75
		277				–2.4081	0.59	0.22

¹⁾ Activation energy in kJ/mol.
²⁾ Rate constant.
³⁾ Initial data of index characteristics attribute.
⁴⁾ Data of index characteristics attribute as t time passes.