Study on enzymatic browning in suspension cultures of licorice cells

Figures & data

Figure 1. Changes of the membrane permeability observed with Evans blue staining of licorice cells in liquid and solid cultures.

Figure 2. Change of cell viability in liquid and in solid cultures by using the TTC method.

Figure 3. Effect of suspension culture on intracellular and extracellular PPO activity.

Figure 4. Elevated production of intracellular + extracellular polyphenols in licorice cell culture after solid–liquid transfer.

Table 1. Degree of suspension cultures' relative browning under series of initial sucrose concentrations (OD_{420 nm} × 10⁻²).

	Sucrose concentrations*
Culture time	10 (g/L)	20 (g/L)	30 (g/L)	40 (g/L)
0 d	22.3 ± 0.42	22.3 ± 0.42	22.3 ± 0.19	22.3 ± 0.42
2 d	27.4 ± 0.17	29.3 ± 0.56	52.3 ± 0.64	58.8 ± 0.62
4 d	29.6 ± 0.92	31.5 ± 0.73	58.8 ± 0.47	67.6 ± 0.84
6 d	28.5 ± 0.35	38.1 ± 0.64	60.4 ± 0.62	72.4 ± 0.67

Note: The results are represented as values ± standard deviations based on three replicates; optical density (OD).

*The values in the table represent the degree of suspension cultures' relative browning (OD_{420 nm} × 10⁻²).

Table 2. Degree of suspension cultures' relative browning under a series of initial agitation speeds (OD_{420 nm} × 10⁻²).

	Agitation speed*
Culture time	80 (rpm)	100 (rpm)	120 (rpm)	140 (rpm)	160 (rpm)
0 d	22.3 ± 0.42	22.3 ± 0.42	22.3 ± 0.19	22.3 ± 0.42	22.3 ± 0.42
2 d	27.6 ± 0.02	33.2 ± 0.05	52.3 ± 0.64	53.9 ± 0.06	56.7 ± 0.14
4 d	31.5 ± 0.47	37.1 ± 0.50	58.8 ± 0.47	60.7 ± 0.19	63.4 ± 0.23
6 d	36.9 ± 0.31	40.8 ± 0.07	60.4 ± 0.62	64.8 ± 0.21	65.2 ± 0.05

Note: The results are represented as values ± standard deviations based on three replicates; optical density (OD).

*The values in the table represent the degree of suspension cultures' relative browning (OD_{420 nm} × 10⁻²).

Figure 5. Effects of modulation agents on PPO activity.

Table 3. Inhibitory effects of two inhibitors (ascorbic acid and L-cysteine).

	Degree of browning (OD420 nm × 10^−2)				Biomass (g Fw/80 mL)
Inhibitors	0 d	2 d	4 d	6 d	0 d	2 d	4 d	6 d	21 d
Ascorbic acid	22.3	36.9 ± 0.42	31.8 ± 0.29	26.7 ± 0.78	3.00	3.53 ± 0.07	4.58 ± 0.10	5.38 ± 0.22	17.3 ± 0.77
L-cysteine		42.2 ± 0.56	32.2 ± 0.64	28.9 ± 1.09		3.32 ± 0.05	3.81 ± 0.10	4.39 ± 0.06	16.7 ± 0.54
Control		52.3 ± 0.64	58.8 ± 0.62	60.4 ± 0.67		3.31 ± 0.07	3.42 ± 0.12	3.98 ± 0.11	13. 2± 0.35

Note: The obtained fresh weight values were the mean of three replicates ± standard deviations; Fresh weight (Fw).