Impacts of alkaline‐electrolyzed water treatment on physicochemical, phytochemical, antioxidant properties and natural microbial load on ‘Granny Smith’ apples during storage

Abstract

Providing consumers with fresh and safe fruit can greatly increase their access to recommended daily intake of phytonutrients. Thus, this study investigated the impact of dipping in alkaline electrolyzed water (AEW) and dipping duration on the physicochemical, phytonutrients and microbial load on 'Granny Smith' apples. Apples treated with AEW (200 and 300 mg L À1 ) were compared to sodium hypochlorite (NaOCl, 200 mg L À1 ) and to non-treated (control) under dipping durations of 10 and 15 min. Apples treated with AEW maintained titratable acidity (TA) and total soluble solids (TSS) compared to other treatments (P > 0.05). Interaction of treatments and storage duration had a significant impact (P ≤ 0.05) on total phenolics and flavonoids contents. Apples treated with AEW better maintained antioxidant capacity compared to control. Treatments with AEW resulted in %2 Log reduction in total aerobic mesophilic bacteria (4.1 Log CFU cm À2 to 2.2 Log CFU cm À2 ) and < 1 Log reduction for yeasts and moulds (3.9 Log CFU cm À2 to 2.7 Log CFU cm À2 ). This study demonstrated the efficacy of electrolyzed water treatment as an alternative to conventional pack-house practices for apple fruit.

Effect of hydroxyl radical water treatment on functional components, volatile compounds and preservation of four different fruits and vegetables

“…After 21 days of storage, both L* values of the control group and the HRW-treated group decreased, indicating that the color of fruits and vegetables became dark, which might be due to the pigmentation (Orsi et al, 2021) and enzymatic browning (Zheng et al, 2019). The a* and b* values were not significantly affected by the duration of storage (p > 0.05), which is consistent with some studies (Nyamende et al, 2022;Wu et al, 2021). index both changed more slightly in the treated groups than that in the control, indicating that HRW treatment could effectively slow down the color change and decay of fruits and vegetables, which might be caused by the effectiveness of HRW in removal of organic contaminants and microorganisms (Wojnárovits et al, 2022;Liao et al, 2021).…”

“…2c, the reduction percentages in phenolic content of the four groups were 1.65%, 3.91%, 9.18%, and 17.95%, the decrease in ascorbic acid content was less pronounced, at 0.79%, 0.63%, 4.81%, and 13.01%, respectively. Similar observations were reported by Nyamende et al (2022) and Puligundla et al (2018). We speculate that since the proportionality of weight/area or volume/area of vegetables was generally smaller than that of fruits, this might lead to more severe losses of phenolics and ascorbic acid, but no significant effect on sugars (p > 0.05).…”

“…It was found that reducing sugars and total phenols were lost up to 9.83%, while a significant decrease in the sensory evaluation was observed after treatment of 60 s (Puligundla et al, 2018). Also, EW could make volatile substances change in persimmon wine (Zhu et al, 2016), and had undesirable effects on the sensory quality of food (Rahman et al, 2011;Nyamende et al, 2022;Yang et al, 2009;Yang et al, 2020). To our best knowledge, the effects of HRW treatment on the quality of fruits and vegetables have never been reported.…”

“…Electrolyzed water (EW) has been widely reported as the most efficient washing alternative (Nyamende et al, 2022;Jia et al, 2022). It is generated by electrolysis of a saline solution such as sodium chloride (Huang et al, 2008), accordingly, the chloride produced in this process can alter the taste of fruits and vegetables (Hassenberg et al, 2008).…”

Impact of electrolyzed water as pre-treatments on drying properties and total colour difference of fresh-cut ‘Tommy Atkins’ mangoes

“…Electrolyzed water was generated in-house as described by Nyamende et al [ 19 ] and Belay et al [ 20 ]. Fresh-cut mango slices were divided into four batches based on the total dipping pre-treatment steps before drying and corresponding to the following treatments: (a) slices were dipped for 10 min, in acidic electrolyzed water (AEW, using KCl) solution (200 mg/mL); (b) slices were dipped for 10 min, in alkaline electrolyzed water (AIEW, using NaCl) solution (200 mg/mL); (c) slices were dipped, in 1% SMB (10 g/kg) solution for 2 min (to mimic stand industry practice); and (d) non-treated samples as control.…”