Browsing by Author "Caleb, Oluwafemi James"

Now showing 1 - 2 of 2
  • Thumbnail Image
    Item
    Effects of acidic and alkaline electrolyzed water treatments on the volatilomics and proteomics changes in fresh-cut apple during storage
    (Royal Society of Chemistry, 2025) Caleb, Oluwafemi James; Belay, Zinash A.; Nkomo, Mbukeni
    Electrolyzed water (EW) has shown potential to decontaminate and maintain the quality of fresh-cut apple; however, the underlying response of the product to this treatment remains unclear. Thus, this study aims to identify the possible quality regulation mechanisms of acidic electrolyzed water (AEW) and alkaline electrolyzed water (ALEW) treatments on fresh-cut ‘Granny Smith’ apples via volatile organic compound (VOC) and qualitative proteomics analysis during storage at 2 °C for 10 days. The results identified 43 VOCs, including 10 esters, 9 alcohols, 9 alkanes, 8 carboxylic acids, 6 ketones, and 1 aldehyde. The distribution of VOCs was significantly affected by the pretreatment conditions; fresh-cut apple treated with AEW was characterised by the highest number of esters, alcohols, and carboxylic acids, whereas samples treated with ALEW exhibited predominantly carboxylic acids, alcohols, and alkanes in comparison to control (untreated) samples. Ethyl dodecanoate, which was identified only in the ALEW samples on each sampling day, had the highest concentration among all the individual VOCs. The proteomics results showed that a total of 3434, 3401, and 3313 proteins were identified on day 3, 6, and 10, respectively, across all samples. Until day 6 of storage, no significant differences were observed among the samples. Notably, on day 6, “M16C_associated domain-containing protein” was shown to be unique to the control samples. KH type-2 domain-containing protein, methylenetetrahydrofolate reductase (MTHFR), and 1,4-alpha-glucan branching enzyme were unique proteins identified after AEW treatment at day 6 and 10 of storage. No unique protein was identified for the ALEW samples. These results provide the first report of the proteomic and volatilomic changes associated with EW-treated fresh-cut apple during storage. Data are available via ProteomeXchange with identifier PXD056621. © 2025 RSC.
  • Thumbnail Image
    Item
    Enzymatic and proteomic exploration into the inhibitory activities of lemongrass and lemon essential oils against botrytis cinerea (causative pathogen of gray mold)
    (Front. Microbiol, 2023) Klein, Ashwil; Kgang, Itumeleng Eugenia; Mohamed, Gadija G.; Mathabe, Patricia M. K.; Belay, Zinash A; Caleb, Oluwafemi James
    Introduction: Essential oils (EOs) have been demonstrated as efficacious against B. cinerea. However, the underpinning enzymatic and proteomic mechanism for these inhibitory effects is not entirely clear. Methods: Thus, this study examined the effects of lemon (Le) and lemongrass (Lg) EOs (individually and in combination) against B. cinerea based on enzymatic and proteomic analyses. Proteomics data are available via ProteomeXchange with identifier PXD038894. Results and discussion: Both EOs (individually and in combination) displayed abilities to induce scavenging as observed with the reduction of H2O2. Measured malondialdehyde (MDA) and superoxide dismutase (SOD) activity were increased in all EOs treated B. cinerea mycelia compared to the control. Ascorbate peroxidase (APX) activity was highest in Lg treated B. cinerea (206% increase), followed by combined (Le + Lg) treatment with 73% compared to the untreated control. Based on GC-MS analysis, the number of volatile compounds identified in lemon and lemongrass EOs were 7 and 10, respectively. Major chemical constituent of lemon EO was d-limonene (71%), while lemongrass EO was a-citral (50.1%). Based on the interrogated LC-MS data, 42 distinct proteins were identified, and 13 of these proteins were unique with 1, 8, and 4 found in Le-, Lg-, and (Le + Lg) EOs treated B. cinerea, respectively, and none in control. Overall, 72% of identified proteins were localized within cellular anatomical entity, and 28% in protein-complexes. Proteins involved in translation initiation, antioxidant activity, protein macromolecule adaptor activity and microtubule motor activity were only identified in the Lg and (Le + Lg) EOs treated B. cinerea mycelia, which was consistent with their APX activities.