# 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 the Ripening and Shelf Life of Fruits
Electrostatic treatment is a low energy, nonheated treatment technology and may be influenced to maintain a specific respiration rate for specific fruits and vegetables. Expanding the shelf life of the fruit is possible through curtailment and lag of the respiration of fruits resulting off the containment of ethylene generation [102]. [PERSON] et al. (2008) found that a negative high-level treatment electrostatic field (\(-2\) kV/cm) treating, with its capability to upgrade respiration and ethylene out-turn, can daff tomato fruit maturation and prolong postharvest life during storage for about 7-10 days [102]. [PERSON] and [PERSON] (1996) stated that a high-voltage electric field (430 kV/m) treatment of pears, plums, and bananas in the preclimacter period suppressed the respiration rate during the climacteric period. Similarly, little effect on the respiration rate was also observed in apples treated by HVEF in a postclimacteric period [98]. The physicochemical properties (i.e., Brix, pH, hardness, and Hunter \"Lab\" values) of bananas 17 days after HVEF treatment indicated that HVEF treatment retarded ripening (1.5-2 days) as compared to the control. However, the ethylene production rate in apples and bananas was not affected by a HVEF. The ripening of mature green bananas and sweet peppers was delayed by the exposure of HVEF [98]. [PERSON] et al., 2018 found that the climacteric peak for tomatoes was delayed for 3 days in all HVEF pre-treatments at 2 kV/cm applied for 2 h [99]. [PERSON] et al. (2008) assumed that treatment of a \(-2\) kV/cm electrostatic field can efficiently avoid the decrease in firmness and colour progression in tomato fruit, while similar effects were not monitored in fruit treated with a positive electrostatic field. The pitch of respiration as well as ethylene generation of tomato fruit during storage were lagged by 6 days [102]. [PERSON] at al. (2008) and [PERSON] et al. (2011) confirmed the earlier observations that ethylene output of tomato fruits treated from HVEF was lower before that of the control fruits and that a negative HVEF treatment can inhibit the production of ethylene more efficiently than a positive HVEF treatment [102; 103]. However, [PERSON] et al. (2004) demonstrated that a positive high-voltage electrical field (1.5 kV/cm) pre-treatment had an effect on the respiration and antioxidant capability of mango fruit, though did not have some prominent effect on firmness and rind colour of mango fruit. HVEF can also affect the inhibition rate of carbon dioxide, indicating that it has the ability to inhibit metabolism and delay organisational deterioration [119]. [PERSON] et al. (2004) found that, after 21 and 39 days in storage, apples treated with 36 and 48 kV showed a lower amount of CO\({}_{2}\) than samples in a non-reversed electric field [97]. In another study, it was shown that 1- or 2-h treatment periods at 10 and 20 kV reduced respiration in apples [96]. Other research showed that an uncompensated geomagnetic field may have an effect on the inhibition rate of carbon dioxide during storage of Jonagold apples. The difference between treated and control samples was 20 mg per kg of fruit in storage [97]. The literature reports that a magnetic field of appropriate intensity accelerates the rate of fruit ripening. The magnetic field accelerates the synthesis of carotenoids, beta-carotene and lycopene. The ripening of the fruit in a magnetic field accelerates the characteristic changes in acids and sugars. PM increases the firmness of the fruit, extending its shelf life [91, 92, 93, 107]. Many studies confirm that the electric field extends the shelf life of the fruit. HVEF slows down the respiration rate, affects the production of ethylene, and slows down the ripening of the fruit. The electric field prolongs the shelf life and freshness of the fruit by inhibiting the activity of enzymes and the inhibition of microbial action [97, 102, 109, 119].