Study on the Inhibitory Activity of a Synthetic Defensin Derived from Barley Endosperm against Common Food Spoilage Yeast.

Laila N Shwaiki,Elke K Arendt,Aylin W Sahin

doi:10.3390/molecules26010165

Laila N Shwaiki, Elke K Arendt + Show 1 more

Open Access

https://doi.org/10.3390/molecules26010165

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Abstract

In the food industry, food spoilage is a real issue that can lead to a significant amount of waste. Although current preservation techniques are being applied to reduce the occurrence of spoilage microorganisms, the problem persists. Food spoilage yeast are part of this dilemma, with common spoilers such as Zygosaccharomyces, Kluyveromyces, Debaryomyces and Saccharomyces frequently encountered. Antimicrobial peptides derived from plants have risen in popularity due to their ability to reduce spoilage. This study examines the potential application of a synthetic defensin peptide derived from barley endosperm. Its inhibitory effect against common spoilage yeasts, its mechanisms of action (membrane permeabilisation and overproduction of reactive oxygen species), and its stability in different conditions were characterised. The safety of the peptide was evaluated through a haemolysis and cytotoxicity assay, and no adverse effects were found. Both assays were performed to understand the effect of the peptide if it were to be consumed. Its ability to be degraded by a digestive enzyme was also examined for its safety. Finally, the peptide was successfully applied to different beverages and maintained the same inhibitory effects in apple juice as was observed in the antiyeast assays, providing further support for its application in food preservation.

Highlights

Saccharomyces cerevisiae and Zygosaccharomyces rouxii were only inhibited at the highest concentration of 400 μg/mL (MFC and minimum inhibitory concentration (MIC) range of 200−400 μg/mL, respectively)
The fungicidal activity of the peptide was observed at all inhibitory concentrations against Z. bailii and S. cerevisiae, while only at 200 and 400 μg/mL
The current study examined the effect of a synthetic peptide derived from the barley endosperm, referred to here as defensin-like protein 1 (D-lp1), on the growth of common food spoilage yeast

Summary

Introduction

The development of physical traits such as thorns and spines is a tool that can deter herbivores [1] Amongst these complex mechanisms is the production of antimicrobial peptides (AMPs), which are known to challenge the presence of microbial and fungal infections. They are part of the innate immune system of a plant and can differ based on their structure and their selective nature [2]. Their cationic and cysteine-rich sequences make them effective agents against microbial and fungal cells, but less so towards mammalian cells due to their weaker affinity to neutrally/positively charged membranes [3]. Snakins/GASA, hevein- and knottin-type peptides, and cyclotides are other well-recognised plant AMPs known for their impact on plant defence systems [5]

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