Encapsulation of wild oregano, Plectranthus amboinicus (Lour.) Spreng, phenolic extract in baker's yeast for the postharvest control of anthracnose in papaya

Abstract

BACKGROUND Anthracnose caused by Colletotrichum gloeosporioides is considered as a major postharvest disease affecting many fruits. This plant disease is traditionally managed with synthetic fungicides, which are generally toxic and are linked to pathogen resistance. Recently, microencapsulated bioactives have been developed as potential alternative strategies to these methods, while utilizing natural fungicides and other phytochemicals. Wild oregano, Plectranthus amboinicus (Lour.) Spreng, contains potent antimicrobial phenolics, but these compounds are volatile and relatively unstable, which limits their efficacy during application. Herein, a baker's yeast microencapsulation system was applied to improve the stability of wild oregano phenolic extract (WOPE) and enhance its antifungal activity against anthracnose. RESULTS Encapsulation of WOPE in plasmolyzed yeast cells afforded a high encapsulation efficiency (93%) and yielded WOPE‐loaded yeast microcapsules (WLYMs) with an average diameter of 2.65 μm. Storage stability studies showed WLYMs are stable for at least 4 months. A 24 ‐h in vitro release experiment showed that WLYMs had an initial burst release upon redispersion in water, followed by a controlled release to about 80% of the loaded WOPE. Upon application as a spray‐type postharvest treatment for papaya, WLYMs exhibited a significantly improved mycelial inhibitory action against C. gloeosporioides and greatly reduced the anthracnose symptoms in papaya fruits. CONCLUSION This study presented a yeast microencapsulation system that can effectively stabilize WOPE and enhance its antifungal activity, making this microparticle formulation a promising environmentally safe postharvest treatment option to combat anthracnose symptoms in papaya fruits. © 2022 Society of Chemical Industry.

Microencapsulation of olive mill wastewater in Saccharomyces cerevisiae cells by spray drying and in vitro bioaccessibility of phenolic compounds

“…There have been methods for the utilization of this byproduct including the extraction of OMW phenolics and encapsulation of this extract into ethylcellulose particles, 3,4 calcium-alginate, 5 maltodextrin/acacia fiber, 6 and whey protein/maltodextrin microparticles, 7 or converting the pretreated OMW (centrifugated, ultra-and nanofiltered) directly into spray-dried powders by using different carriers such as skimmed-milk and/or maltodextrin. [8][9][10][11][12][13] Recently, there is also an increasing interest in the use of yeast cells (YCs) as an encapsulation agent for both hydrophilic and lipophilic compounds such as gallic acid, 14 chlorogenic acid, 15 anthocyaninrich hibiscus extract, 16 curcumin, 17,18 essential oil, 19,20 wildoregano phenolic extract, 21 and krill oil. 22 Baker's yeast cells can be considered effective encapsulation agents due to their low cost, non-toxicity, nutritional benefits, and resistance to temperature applied during spray-drying.…”