Investigating the Effect of Magnetic Field, Fennel (Foeniculum vulgare) Essential Oil and Aloe vera Gel on the Browning of Fresh-cut Apples

there is a growing request for healthy fresh-cut products globally. However, due to the higher respiration of this kind of products and their suseptability to bacterial and fungal pathogenes, they spoil immediately after processing. These microbial activities usually cause a decrease in the quality and marketability of the product, including changes in its aroma, taste and appearance. The fresh-cut fruit and vegetable industry is one of the relatively new sectors and while the industry is growing, it is producing new products. Tissue rupture and cell rupture in these products leads to a decrease in their shelf life. On the other hand, these products need serious attention due to increased enzymatic activity, respiratory factors and microbiological considerations.In recent years, there has been growing evidence of consumption of minimally processed fruits and vegetable for the prevention of many chronic diseases. Some chemicals like chlorine, calcium chloride, etc., are used for sanitization purpose in fruit and vegetable industry, but these chemicals form carcinogenic chlorinated compounds, which have adverse human health impacts. Therefore, advanced alternative sanitization techniques, processing methods and improved packaging materials may be implemented for ensuring safety and extending the shelf life of fresh-cut fruit and vegetables. Application of edible coatings showed acceptable results on microbial load reduction and better preservation of processed products from the fruit to vegetables. Apple with proper nutritional value as a healthy snack have been considered in the diet of schools, public consumption and families. Finding a safe treatment to increase shelf life of freshly cut apples without harmful effets on environment and consumer is the main goal to this reaserch.   In this study, the effect of fennel essential oil (Foeniculum vulgare L.) with Aloe vera gel (in 3 levels of zero, 10 and 25 ml / l) and two magnetic field intensity (0 and 60 ml Tesla) in 3 replications during 7 days and in two storage  temperatures (8 and 25 ° C) were observed. All treatments except the control were coated with Aloe vera gel. It was done in factorial format with a completely randomized design. In which traits such as color quality, SSC, pH, physiological weight loss, and browning rate were studied.   Discussion and The results showed that the presence of the magnetic field in all samples treated with Aloe vera gel reduced the degradation, decrease oxidation and increase preservation of the appearance indices of apple slices. The presence of Aloe vera gel in all cases reduced water content reduction and weight loss. In the samples treated with different levels of fennel essential oil, fungal and bacterial growth was prevented, but in terms of appearance indices, it had a great decrease in quality and increased browning. No mold and fungal growth was observed in the samples at 8 and 25 ° C. Apparently, apples treated with 25 ml of essential oil lost their marketability. The use of Aloe vera treatment alone and without essential oil with a 60 ml Tesla magnetic field was found to be the best treatment. In general according to the results of this study, the application of fennel essential oil, which has antioxidant properties in lower concentrations, is useful to prevent the prevent fungal and bacterial growth, but is not suitable in terms of maintaining the appearance and reducing tissue destruction and causes faster and higher oxidation. Apple slices treated with high essential oil concentration became completely brown and lost their marketability even more than the control samples. Finally, it could be said that Aloe vera gel treatments in which a magnetic field was applied, in addition to water retention, had the best appearance and less oxidation. However, the use of Aloe vera gel and magnetic field to maintain the appearance is very useful and can be used in this industry.