Antioxidant Benefits and Potential Mechanisms of Slightly Acidic Electrolyzed Water Germination in Sesame

Abstract

Slightly acidic electrolytic water (SAEW) treatment for seed germination is a promising technique for sustainable agriculture. This study investigated the antioxidant activity of germinated sesame seeds treated with SAEW for the first time. Specifically, the impact and correlation of SAEW on the activities of total phenols, total flavonoids, and antioxidant oxidase in sesame seeds were examined. The results showed that SAEW with low ACC inhibited sesame germination, SAEW with high ACC promoted sesame germination, and sesame buds treated with SAEW with 30 mg/L and 50 mg/L ACC showed lower antioxidant activity and total phenolic and flavone content compared to tap water. In contrast, SAEW with 30 mg/L ACC had no significant effect on sesame growth but positively influenced the antioxidant activity of sesame seed germination by promoting phenolic compound synthesis through increased phenylalanine ammonia-lyase (PAL) activity and enhancing antioxidant activity by boosting PAL, polyphenol oxidase (PPO), and peroxidase (POD) activities. Generally, antioxidant ability was the most prominent in SAEW with 30 mg/L ACC, and positive correlations between antioxidation and total phenols and flavonoids content were found in sesame. These findings provide valuable insights into the mechanisms underlying the enhanced antioxidant capacity observed in germinated sesame seeds under SAEW stress.

Keywords: antioxidant activity; antioxidant enzymes; sesame; slightly acidic electrolytic water.

Figure 1

The changes in (a) shoot length at 48 h, (b) germination rate, (c) fresh weight, and (d) dry weight of 100 grains during germination of sesame treated by slightly acidic electrolyzed water (SAEW) during germination. The pH and available chlorine concentration (ACC) of SAEW used in the experiment were 5.9 ± 0.1 and 10, 20, 30, 40, 50 mg/L, respectively; the tap water (TW) as control was the local drinking water. Samples were taken at 0, 12, 24, 36, 48 h of germination. Each value is expressed as the mean ± standard deviation of three replicates. Different superscripts (a–f) show significant difference in duration of germination (p < 0.05). SAEW is significantly different from the control and is indicated by * (p < 0.05) and ** (p < 0.01).

Figure 2

The changes in (a) DPPH, (b) ABTS, (c) hydroxyl radical scavenging ability, and (d) Fe³⁺ reducing ability of sesame treated by slightly acidic electrolyzed water (SAEW) during germination. The pH and available chlorine concentration (ACC) of SAEW used in the experiment were 5.9 ± 0.1 and 10, 20, 30, 40, 50 mg/L, respectively; the tap water (TW) as control was the local drinking water. Samples were taken at 0, 12, 24, 36, 48 h of germination. Each value is expressed as the mean ± standard deviation of three replicates. Different superscripts (a–e) show significant difference in duration of germination (p < 0.05). SAEW is significantly different from the control and is indicated by * (p < 0.05) and ** (p < 0.01).

Figure 2

The changes in (a) DPPH, (b) ABTS, (c) hydroxyl radical scavenging ability, and (d) Fe³⁺ reducing ability of sesame treated by slightly acidic electrolyzed water (SAEW) during germination. The pH and available chlorine concentration (ACC) of SAEW used in the experiment were 5.9 ± 0.1 and 10, 20, 30, 40, 50 mg/L, respectively; the tap water (TW) as control was the local drinking water. Samples were taken at 0, 12, 24, 36, 48 h of germination. Each value is expressed as the mean ± standard deviation of three replicates. Different superscripts (a–e) show significant difference in duration of germination (p < 0.05). SAEW is significantly different from the control and is indicated by * (p < 0.05) and ** (p < 0.01).

Figure 3

The changes in (a) total phenolic contents (TPC) and (b) total flavonoid contents (TFC) of sesame treated by slightly acidic electrolyzed water (SAEW) during germination. The pH and available chlorine concentration (ACC) of SAEW used in the experiment were 5.9 ± 0.1 and 20, 30, 40 mg/L, respectively; the tap water (TW) as control was the local drinking water. Samples were taken at 0, 12, 24, 36, 48 h of germination. Each value is expressed as the mean ± standard deviation of three replicates. Different superscripts (a–e) show significant difference in duration of germination (p < 0.05). SAEW is significantly different from the control and is indicated by * (p < 0.05) and ** (p < 0.01).

Figure 4

The changes in (a) SOD, (b) POD, (c) CAT (d) APX, (e) PAL, (f) PPO activities of different antioxidant enzymes of sesame treated by slightly acidic electrolyzed water (SAEW) during germination. The pH and available chlorine concentration (ACC) of SAEW used in the experiment were 5.9 ± 0.1 and 20, 30, 40 mg/L, respectively; the tap water (TW) as control was the local drinking water. Samples were taken at 0, 12, 24, 36, 48 h of germination. Each value is expressed as the mean ± standard deviation of three replicates. Different superscripts (a–e) show significant difference in duration of germination (p < 0.05). SAEW is significantly different from the control and is indicated by * (p < 0.05) and ** (p < 0.01).

Figure 5

The Pearson correlation coefficient changes in antioxidant activities, the total phenolic, flavonoid, and activity of antioxidant enzyme of sesame seeds during germination under (a) the tap water (TW) and (b) slightly acidic electrolyzed water (SAEW). The pH and available chlorine concentration (ACC) of SAEW used in the experiment were 5.9 ± 0.1 and 30 mg/L.