Cow and camel milk-derived whey and casein protein hydrolysates demonstrated effective antifungal properties against selected Candida species

Priti Mudgil,May Almazroui,Ali Ali Redha,Bhanu Priya Kilari,Shabarinath Srikumar,Sajid Maqsood

doi:10.3168/jds.2021-20944

Priti Mudgil, May Almazroui + Show 4 more

Open Access

https://doi.org/10.3168/jds.2021-20944

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Abstract

Bioactive peptides derived from milk proteins are widely known to possess antibacterial activities. Even though the antibacterial effects of milk-derived peptides are widely characterized, not much focus is given to their antifungal characterization. Therefore, in this study, we investigated the antifungal properties of camel and cow whey and casein hydrolysates against various species of pathogenic Candida. The hydrolysates were produced using 2 enzymes (alcalase and protease) at differing hydrolysis durations (2, 4, and 6 h) and tested for their antifungal properties. The results showed that intact cow whey and casein proteins did not display any anti-Candida albicans properties, whereas the alcalase-derived 2 h camel casein hydrolysate (CA-C-A2) displayed a higher percentage of inhibition against Candida albicans (93.69 ± 0.26%) followed by the cow casein hydrolysate generated by protease-6 h (Co-C-P6; 81.66 ± 0.99%), which were significantly higher than that of fluconazole, a conventional antifungal agent (76.92 ± 4.72%). Interestingly, when tested again Candida krusei, camel casein alcalase 2 and 4 h (CA-C-A2 and CA-C-A4), and cow whey alcalase-6 h (CO-W-A6) hydrolysates showed higher antifungal potency than fluconazole. However, for Candida parapsilosis only camel casein alcalase-4 h (Ca-C-A4) and cow casein protease-6 h (Co-C-P6) hydrolysates were able to inhibit the growth of C. parapsilosis by 19.31 ± 0.84% and 23.82 ± 4.14%, respectively, which was lower than that shown by fluconazole (29.86 ± 1.11%). Overall, hydrolysis of milk proteins from both cow and camel enhanced their antifungal properties. Camel milk protein hydrolysates were more potent in inhibiting pathogenic Candida species as compared with cow milk protein hydrolysates. This is the first study that highlights the antifungal properties of camel milk protein hydrolysates.

Highlights

Fungal infections are a major problem for immunocompromised patients
The degree of hydrolysis (DH) for each hydrolysate produced with each enzyme and hydrolysis time was determined by measuring the soluble peptide released during hydrolysis, and the results reported as percentages are shown in Figure 1 (A–D)
For camel casein hydrolysates obtained via protease and alcalase hydrolysis, DH values were observed to be 38.22%, 49.08%, 83.47% and 42.03%, 70.77%, 97.79% for casein hydrolysates generated with alcalase-2 h (Ca-C-A2), casein alcalase-4 h (Ca-C-A4), Ca-C-A6 and Ca-C-P2, Ca-C-P4, and Ca-C-P6, respectively

Summary

Introduction

Fungal infections are a major problem for immunocompromised patients. Candida albicans is the most infective among 17 Candida species that can cause human infections (Dadar et al, 2018). A commensal fungus usually observed infecting the human oral cavity and gastrointestinal tract, is one of the main causes of mucosal and systemic infections (Mayer et al, 2013; Nobile and Johnson, 2015). These fungal infections are linked with high mortality rates among people with compromised immune systems (Li et al, 2016). The development of parallel antifungal therapeutic strategies for candidiasis patients, especially, is very important (de Oliveira Santos et al, 2018)

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