Natural Antimicrobials from Cloudberry (Rubus chamaemorus) Seeds by Sanding and Hydrothermal Extraction

Riitta Puupponen-Pimiä,Tuulikki Seppänen-Laakso,Kirsi-Marja Oksman-Caldentey,Juha Tähtiharju,Juha-Pekka Salminen,Jussi Suvanto,Kaisu Honkapää,Liisa Nohynek

doi:10.1021/acsfoodscitech.0c00109

Riitta Puupponen-Pimiä, Tuulikki Seppänen-Laakso + Show 6 more

Open Access

https://doi.org/10.1021/acsfoodscitech.0c00109

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Abstract

We have developed an organic solvent-free process to enrich natural antimicrobials from the important Nordic Rubus berry species, especially from cloudberry. The process utilizes industrial berry byproducts as raw-material, and it is based on seed sanding technology and water-based extraction. The extracts showed strong antimicrobial activity against Gram-positive Staphylococcus aureus and methicillin-resistant Staphylococcus aureus (MRSA). A concentration of 5 mg/mL totally eliminated these bacteria in 24 h. Effects against Gram-negative bacteria were modest. Polyphenol analysis of the hydrothermal extracts showed that the antimicrobial activity is correlated to ellagitannins, mainly dimeric sanguiin H-6 and sanguiin H-10 isomers. Sanguiin H-10 is not commonly found in intact cloudberry seeds, but it is formed from the dimeric and trimeric ellagitannins, during the extraction. Surprisingly hydrothermal extracts had no or minor effects on beneficial bacteria, Lactobacillus rhamnosus. This interesting finding might offer an application potential in controlling skin microbial pathogens, for example, in wound healing.

Highlights

Cloudberry (Rubus chamaemorus) is a perennial herb with boreal distribution
We describe here the seed sanding technology, in which antimicrobially active ellagitannins can be recovered from the outer layer of the cloudberry seeds by sanding technology, followed by gentle extraction
In this study we show that the cloudberry seed fractions, rich in ellagitannins, possess strong antimicrobial activity against

Summary

Introduction

Cloudberry (Rubus chamaemorus) is a perennial herb with boreal distribution. In Finland, cloudberries grow especially in the undrained wetlands in Northern Finland, where they produce the highest yield. The annual crop of cloudberries in Finland is estimated to be a few million kilograms. Cloudberry fruit is of economic importance in Nordic countries, and it is a desired raw material for the food, beverage, and cosmetic industries. The juice is used by the food and beverage industry for liqueurs, jams, and jellies. After juice pressing the remaining press cake, cloudberry pomace, which largely contains seeds, is mainly used for seed oil extraction for the cosmetic industry. We recently developed a dry fractionation method for cloudberry pomace based on dry fractionation using milling and sieving technologies in order to obtain bioactive fine and coarse fractions.[1]

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