Investigation of the impact of cold plasma pretreatments, long term storage and drying on physicochemical properties, bioactive contents and microbial quality of 'Keitt' mango

Abstract

There is heightened demand for dried mango fruits with desired nutritional and physicochemical qualities, microbiologically stable and chemical residue free. This has led to the exploration of innovative preservation technologies for the extension of storability prior to processing. This study investigated the impact of cold plasma (CP) treatment on physicochemical properties and microbial stability in fresh and dried 'Keitt' mango during long term storage. Freshly harvested 'Keitt' mangoes were subjected to: CP treatment (for 5 min (CP5) and 10 min, CP10), dipping in “Chronos Prochloraz” for 30 s (industry practice), and untreated group (control). All samples were stored at 11 °C for 30 days, prior to minimal processing and hot air drying at 60 °C. Results after 30 days of storage demonstrated that untreated samples (control) had the highest TSS (15.06 ± 0.32 °Brix), while CP10 pretreated samples had the lowest TSS (13.80 ± 0.06 °Brix) value (p ≤ 0.05). In comparison to the fresh samples post storage, all pretreated dried mango slices retained lower total flavanols with CP5 (13.49 ± 1.64 mg GAE 100/g), CP10 (20.12 ± 1.42 mg GAE 100/g) and SMB (23.89 ± 3.35 mg GAE 100/g), but higher than the dried untreated samples (6.68 ± 0.53 mg GAE 100/g). Yellowness (b∗) of the fresh pulp (38.53 ± 1.73) increased significantly (p ≤ 0.05) with the long-term storage (39.88–46.74) and drying (55.01–64.90). CP pre-treatment combined with drying resulted in ≥2 Log reduction in microbial count. This study shows the potential of cold plasma as a pretreatment for extending storability and maintaining the quality of 'Keitt' mangoes.

Keywords

• Fruit colour
• Antioxidant capacity
• Total phenols
• Sustainable development goals