# 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  
A summary of the effect of MF and EF on the ripening and shelf life of fruits is presented in Table 2. \begin{table}
\begin{tabular}{c c c c c} \hline \hline
**Variety** & **Method** & **MF Parameter** & **Effect** & **References** \\ \hline \multirow{3}{*}{Apples _Melrose_, _Champion_, _Corland_} & Fruit & SPMF 200 mT & Change in firmness depending on variety, increase in _Melrose_ & \multirow{3}{*}{[PERSON] 2001} \\  & & treatment & within storage & decrease in _Champion_, no change in _Corland_ & [91] \\ \cline{3-5}  & & exposure time 5 \(\times\) 30 & in _Corland_ & \\ \cline{3-5}  & & MF & Increase in ripening rate, beta caroten and lycopene, sugar concentration and decrease in acidity and respiration rate & [92] \\ \cline{3-5}  & & & Low MF did not influence & [PERSON] et al., 2012 \\ \cline{3-5}  & & storage period & in colour, firmness, lycopene concentration & [93] \\ \hline \hline \end{tabular}
\end{table} 
Table 2: Summary of the total effect of magnetic fields and electrical fields on the ripening and shelf life of fruits. \begin{table}
\begin{tabular}{c c c c c} \hline \hline
**Variety** & **Method** & **MF Parameter** & **Effect** & **References** \\ \hline Strawberries & & SPMF 5–100 mT, & & & \\ _Bogota, Elkat,_ & Fruit treatment & AMF 50–150 uT & Increase in firmness with AMF for & [PERSON] et al., 2010 \\ _Ventana,_ & during vegetative & and 5–100 mT & 50–150 uT up to 30\% & [94] \\ _Honeye, Salut_ & period on plants & for 5 replicates each 5 days & Increase in storage time by slowing down the process of enzymatic decomposition of starch and intensity of respiration. Lower content of simple sugars, ash and greater calorific value, volatile compounds and water content were recorded & [PERSON] et al., 2020 \\ Apple & Fruit treatment & & Increase in soluble sugar concentration, and decrease in CO\({}_{2}\) production, it becomes & [PERSON] et al., 2003 \\ _[PERSON]  
The effect of magnetic and electrical fields on the postharvest physiology of fruits is a new and a not yet exhausted area of research. Metabolic activity continues after harvest of fruits, thus making most types of fruit highly perishable commodities. As the fruit ripens, respiration increases and their flesh begins to soften and will reach senescence [24; 107; 108; 109]. [PERSON] and [PERSON] (1963, 1968) reported that a magnetic field exerted a positive effect on the ripening of fruits [92]. MF brought forward the ripening rate of tomato fruit. This acceleration was manifested in increased colour development. The increase in colour development was due to accelerated synthesis of carotenoids, beta caroten, and lycopene. The fruit ripened in the magnetic field also showed characteristic changes in acids and sugars that accompany ripening [92]. However, [PERSON] et al. (2012) showed that MF, at the low doses used in these experiments, did not influence the ripening of tomato fruit during storage at 16 \({}^{\circ}\)C. No significant difference was observed in colour change and weight loss between control and magnetic-field-exposed fruit. Lycopene concentration, firmness, and membrane permeability were also no different between the control and exposed fruit. It was concluded that a higher intensity of magnetic field may be necessary to have an impact on the ripening behaviour of tomatoes [93]. [PERSON] (2001) stated that a strong magnetic field of 200 mT boosts the firmness of Melrose apples and, as a result, the storage period was extended by 20 days. However, in the case of the Champion variety, a field of this value was destructive [91]. [PERSON] (1964) stated that magnetic fields could be inhibitory in nature because of the reduced incidence of molecular collisions due to the orientation of paramagnetic molecules [107].