Measurement and Modeling of Respiration Rate of Guava (CV. Baruipur) for Modified Atmosphere Packaging

Figures & data

Table 1 Physicochemical properties of guava fruits cv. Baruipur

Parameter	Value*
Physical properties
Fruit weight, g	250 ± 25
Fruit volume, ml	228 ± 12
True density, kg/m^3	1097 ± 43
Specific gravity	1.1 ± 0.15
Physical dimension
Major diameter, mm	72 ± 5
Intermediate diameter, mm	66 ± 2
Minor diameter, mm	65 ± 5
Sphericity	0.94 ± 0.02
Firmness, g	9527 ± 1011
Puncture strength, g	759 ± 142
Hunter Color parameters:
L*	58 ± 5
a*	−18 ± 3
b*	39 ± 3
Hue angle	114 ± 3
Chroma	43 ± 3
Chemical properties
Titrable acidity,% malic acid	0.67 ± 0.06
Ascorbic acid, mg/100 ml of juice	284 ± 8
Total soluble solids, °Brix	8.5 ± 1.2
*Values presented are average of 10 representative guava fruits and ± indicates the standard deviation.

Table 2 Free volume of respirometer and weight of guava taken for generating the respiration data

Storage temperature °C	Weight of fruits (W), kg	Free volume of respirometer (), ml
0	1.311	4892.47
5	1.397	4800.28
10	1.308	4895.82
15	1.377	4820.36
20	1.384	4814.65
25	1.325	4878.37
30	1.314	4888.52

Figure 1 Schematic sketch for the closed system method for generation of respiration data.

Figure 2 Experimental data for O₂ consumption and CO₂ evolution at different temperatures; ▴ is Y_O2, in%; ▪ is Z_CO2, in%.

Table 3 Values of regression coefficients for regression model

		Regression coefficients
Storage temperature of guava, °C	Respiration expression in terms of	A	b	r^2
0	O2 consumption	2.595	341.579	0.999
	CO2 evolution	2.622	368.065	0.998
5	O2 consumption	2.615	290.991	0.998
	CO2 evolution	2.432	332.881	0.997
10	O2 consumption	2.965	204.228	0.998
	CO2 evolution	3.071	211.820	0.999
15	O2 consumption	2.678	174.790	0.998
	CO2 evolution	2.716	185.263	0.998
20	O2 consumption	3.366	79.790	0.999
	CO2 evolution	3.483	82.354	0.998
25	O2 consumption	2.555	80.342	0.997
	CO2 evolution	2.468	88.221	0.998
30	O2 consumption	2.875	51.486	0.999
	CO2 evolution	2.482	53.928	0.998

Table 4 Analysis of variance of effect of temperature on regression coefficients

Factor	DF	MSS	F value	MSS	F value	MSS	F value	MSS	F value
Replication	2	0.006	0.496	0.001	0.120	0.086	0.175	540.599	1.105
Temperature	6	0.240	18.844**	0.449	39.978**	37582.787	7677.572**	40752.578**	83.315
Error	12	0.013	—	0.011	—	4.895	—	489.139	—
**Significant at 1% level.

Table 5 Model parameters for uncompetitive inhibition enzyme kinetics for different storage temperatures

Storage Temperature, °C	Respiration expressed in terms of	Vm, ml/kg h	Km,% O2	Ki,% CO2	R^2
0	O2	15.62	9.37	11.27	0.992
	CO2	12.65	4.89	9.29	0.995
5	O2	18.54	10.24	9.46	0.985
	CO2	15.38	6.10	8.16	0.980
10	O2	21.78	11.33	8.22	0.990
	CO2	18.82	7.43	7.23	0.985
15	O2	28.43	12.76	7.15	0.985
	CO2	25.16	8.56	6.35	0.975
20	O2	37.25	13.92	6.42	0.991
	CO2	34.83	9.38	5.67	0.990
25	O2	48.37	14.74	5.80	0.975
	CO2	44.25	10.15	5.10	0.980
30	O2	63.59	15.62	5.17	0.992
	CO2	60.47	10.86	4.53	0.990

Table 6 Analysis of variance of effect of temperature on model parameters of Enzyme kinetics model

Factor	DF	MSS	F value	MSS	F value	MSS	F value	MSS	F value	MSS	F value	MSS	F value
Replication	2	0.14	0.12	0.14	0.12	0.14	0.12	0.07	0.31	0.09	0.35	0.01	0.02
Temperature	6	923.51	808.07**	908.82	795.22**	16.53	14.47**	13.86	64.65**	14.10	51.90**	8.83	106.08**
Error	12	1.14	—	1.14	—	1.14	—	0.21	—	0.27	—	0.08	—
**Significant at 1% level.

Table 7 Slope (−E_a/R) and Y axis intercept (ln R_p) of Arrhenius relation for different model parameters of enzyme kinetics

	Vm		Km		Ki
	O2	CO2	O2	CO2	O2	CO2
Slope	−3927.0	−4375.6	−1461.9	−2168.1	2110.6	1973.2
Y axis intercept	17.044	18.479	7.597	9.603	−5.336	−4.998
r^2	0.984	0.988	0.990	0.960	0.995	0.990

Table 8 Activation energy and pre-exponential factor of Arrhenius type equation for different model parameters of uncompetitive inhibition

	Vm		Km		Ki
Parameters for Arrhenius equation	O2	CO2	O2	CO2	O2	CO2
Ea (kJ/g-mole)	32.64	36.37	12.15	18.02	−17.54	−16.40
Rp	2.5 × 10^7	1.0 × 10^8	1.9 × 10^3	1.4 × 10^4	5.0 × 10^−3	7.0 × 10^−3

Figure 3 Arrhenius relation for different model parameters of enzyme kinetics; ▴ is ; ▪ ; ♦ is ; о is ; Δ is ; □ is .

Table 9 Model parameters of uncompetitive inhibition enzyme kinetics at 12°C storage temperature

Respiration expression in terms of	Maximum respiration rate (Vm), ml kg^−1h^−1	Michaelis-Menten constant (Km), % O2	Inhibition constant (Ki), % CO2
O2 consumption	26.18	11.79	7.92
CO2 evolution	22.78	7.35	6.85

Figure 4 Experimentally estimated and predicted respiration rates for guava at 12°C ‐‐◊‐‐ is for experimental respiration rate; ‐‐□‐‐ is for respiration rate predicted by regression model; ‐‐Δ‐‐ is for respiration rate predicted by enzyme kinetics model.