Pomegranate Byproduct Extracts as Ingredients for Producing Experimental Cheese with Enhanced Microbiological, Functional, and Physical Characteristics

Lucia Parafati,Cristina Restuccia,Biagio Fallico,Rosa Palmeri,Laura Siracusa,Fabiola Pesce

doi:10.3390/foods10112669

Lucia Parafati, Cristina Restuccia + Show 4 more

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https://doi.org/10.3390/foods10112669

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Abstract

Pomegranate peel and mesocarp, considered as wastes of fruit processing, are rich sources of beneficial phytochemicals, including hydrolyzable tannins and flavonoids, with proven antimicrobial and antioxidant activity, which can be employed for improving the overall quality of food products. In the present study, extracts from pomegranate peel (PPW) and mesocarp (PMW) were obtained through a water extraction method and evaluated for in vitro antimicrobial activity and polyphenol content. The two extracts were then added during the cheese-making process in order to create a new functional cheese with improved microbiological and physico-chemical characteristics. Antimicrobial in vitro assays evidenced a substantial efficacy of both extracts against Staphylococcus aureus, which often causes staphylococcal food poisoning outbreaks linked to the consumption of raw milk cheeses and artisanal cheeses. For this reason, a simulated cheese contamination was carried out in order to assess if pomegranate extracts can exert antimicrobial activity towards this pathogen even when incorporated into the cheese matrix. Milk enriched with pomegranate extracts (PPW and PMW) was used to produce two different experimental cheeses, which were then evaluated for yield, polyphenol content, and microbiological as well as physico-chemical traits throughout the refrigerated storage. Despite the low concentration of the extracts, the treated cheeses showed an increase in firmness and a slight decrease in S. aureus counts, of more than one log unit in comparison to the control cheese, for up to 12 d of cold storage. Such results support the reuse of agro-food byproducts, in substitution to chemical food preservatives, as the key to a circular economy.

Highlights

Artisanal cheese is often produced using raw milk, which could represent a vehicle of a broad spectrum of food pathogens such as Listeria monocytogenes, Escherichia coli, Salmonella spp., and Staphylococcus aureus
According to the European Commission Regulation (EC) No 1333/2008 [3] on food additives, preservatives are defined as “substances which prolong the shelf-life of foods by protecting them against deterioration caused by micro-organisms and/or which protect against growth of pathogenic micro-organisms”
The present work evaluated the suitability of two extracts obtained from pomegranate peel and mesocarp to be used as natural food preservatives, which are the most quantitatively representative byproducts of pomegranate processing

Summary

Introduction

Artisanal cheese is often produced using raw milk, which could represent a vehicle of a broad spectrum of food pathogens such as Listeria monocytogenes, Escherichia coli, Salmonella spp., and Staphylococcus aureus The latter, in particular, is considered one of the most hazardous, since several staphylococcal food poisoning outbreaks have been associated with the consumption of raw milk cheeses and artisanal cheese production [1]. The Commission Regulation (EU) No 1129/2011 [4], amending Annex II to Regulation (EC) No 1333/2008, establishes a Union list of food additives for unripened and ripened cheese These preservatives are considered safe for human health in the allowed dosage, but they are largely used in the food industry, increasing their real daily consumption and causing health problems [5]. Worry about the safety of some chemical additives and consumers’ distrust towards them has steered to a rising interest in natural preservatives, such as plant-based compounds

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