# Effect of Magnetic and Electrical Fields on Yield, Shelf Life and Quality of Fruits
## 2 Effect of Magnetic Fields and Electrical Fields on the Growth, Development, and Yield of Fruit
### Effect of Magnetic Fields and Electrical Fields on Fruit Quality
The same results were obtained by [PERSON] et al. (2020) with an electric field (7 kV/cm), showing that, after 15 d of storage, firmness of treated persimmons was higher than the control [127]. Other researchers pointed out that the application of HVEF can effectively reduce deterioration of apple colour postharvest and weight loss during storage [96; 97; 102; 131]. Use of high-voltage electrical field treatment may also maintain the content of ascorbic acid, caroten, antioxidant capacity, taste, fruit colour, and a high level of soluble solids in mango fruits (_Mangifera indica_) for up to 20 days in storage at 5 \({}^{\circ}\)C when compared with a control [119]. [PERSON] et al. (2011) also showed that the content of non-enzyme antioxidants, such as GSH, ascorbic acid, and polyphenols, and the activities of antioxidant enzymes containing catalase, superoxide dismutase, ascorbate peroxidase, as well as peroxidase, in \(-\)2 kV/cm HVEF-treated tomato fruit were pointedly higher before those in the control during storage at 13 \({}^{\circ}\)C [103]. [PERSON] et al. (2011) confirmed that direct current (DC 500 mA for 15 min) treatment of harvested tomatoes affected the secondary metabolism of fruits, which showed a high content of total phenol, lycopene, \(\beta\)-carotene, and antioxidant activity [129]. However, [PERSON] et al. (2008) indicated that the lycopene content in tomato fruit treated with an electrical field was invariably lower before that in control fruit amid the entire storage period [102]. The study of [PERSON] et al. (2017) also showed the benefits of the application of an electrical field in maintaining the physicochemical properties of persimmon fruits. However, they are different according to structure, physiological metabolism, and electric properties from other products [101]. Persimmons treated with 600 kV/m for different lengths of time (0, 30, 60, 90, or 120 min) in samples stored at 25 \({}^{\circ}\)C showed almost 2.5-fold lower pectinesterase (PE) activity after 12 days of storage in comparison with the control [101]. These changes involved the action of cell wall hydrolysis enzymes, such as pectinesterase (PE) and polygalacturonase (PG) [132; 133]. Pectin degradation plays an important role in the ripening of fruit via the disassembly of cellulose that contributes to fruit firmness. [PERSON] et al. (2020) explained the effect of phenolic content on cell membrane integrity [134]. [PERSON] et al. (2021) reported that alternating current electric field (ACEF) with 125 kV/m of intensity for 60 min reduced malondialdehydedehyde (MDA) production and chlorophyll degradation and increased total phenolic content (TPC) of sea grapes during nine days of storage in comparison with the control [128]. The observation by [PERSON] and [PERSON] (1997) that alternant high-voltage electric field treatment could hold up the comedown of chlorophyll and flavonoids in mandarin fruit was confirmed [115]. Delaying the degradation of chlorophyll and malondialdehydedehyde (MDA) production under the effect of an electrical field was also demonstrated by [PERSON] et al. (2008) and [PERSON] et al. (2017) by comparison with the control [101; 102]. [PERSON] et al. (2020) showed increased total phenolic content and enhanced antioxidant activity in persimmon fruits by application of electric field treatment and comparison with a control [127]. This is consistent with the results obtained by [PERSON] al. (2018) for grape extract and [PERSON] et al. (2015) for blueberry, showing the response of plants to induced stress and the inactivation of the enzymes involved in phenolic compound oxidation by an electric field [135; 136; 137]. [PERSON] et al. (2010) stated that the presence of phenolic compounds helps to contribute to the sensory attributes (taste, colour, texture, and aroma) [138]. The mechanism of HVEF is to interfere with the fruit's physiological biochemical metabolism by a high-voltage electrostatic field and, thus, affect the molecules' interaction and dynamics in cells. From the study of [PERSON] et al.