Biodegradable film development by nisin Z addition into hydroxypropylmethylcellulose matrix for mozzarella cheese preservation

Pedro A V Freitas,Nilda F F Soares,Taíla V De Oliveira,Rafael R A Silva,Raquel R A Soares

doi:10.7455/ijfs/9.2.2020.a8

Pedro A V Freitas, Nilda F F Soares + Show 3 more

Open Access

https://doi.org/10.7455/ijfs/9.2.2020.a8

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Abstract

Currently, improvement of food preservation has been a substantial challenge for industries to increase shelf-life of products and to maintain food quality during storage. These goals are often tied to the sustainable tendency for use of eco-friendly packaging to store these products without loss of the packaging features. Therefore, the aim of this study was to produce biodegradable antimicrobial films by the incorporation of nisin Z peptide under different concentrations (0 %, 5 %, 10 %, 15 % and 20 % wt.) into hydroxypropylmethylcellulose (HPMC) matrices. The active film properties were evaluated in terms of their antimicrobial capacity in vitro, mechanical performance and microscopic characteristics. Hence, active films containing 10 % (wt.) of nisin Z and control films were placed in contact with sliced mozzarella cheese for eight days, and microbiological growth was monitored during storage. Nisin Z’s antimicrobial effects were observed against the Gram-positive microorganisms such as Staphylococcus aureus and Listeria innocua, regardless if the compound was free as a suspension or incorporated into HPMC matrices. However, the expected low action of nisin Z against Gram-negative bacteria, as reported in literature, was not observed since Salmonella enterica Choleraesuis’s growth was inhibited. Moreover, active films with added nisin Z (10 % wt.) were more effective than the control film to inhibit mesophilic microorganisms in mozzarella cheese during 8 days of storage. The mechanical properties of the films were not influenced by nisin Z incorporation, since the addition of the compound enhanced the active function without the loss of mechanical properties required for a good food packaging. These results suggest that biodegradable films produced by nisin Z addition into HPMC matrix are an excellent biomaterial for mozzarella cheese preservation.

Highlights

Food packaging is a great strategy to differentiate products in the market under consumers’ attention
The Minimum Inhibitory Concentration of nisin Z (MIC) for the bacteria L. innocua and S. aureus were in agreement with inhibition concentrations reported by other authors (Niaz et al, 2018; Ramos et al, 2012; Sadiq et al, 2016; Yoneyama, Fukao, Zendo, Nakayama & Sonomoto, 2008)
HPMC-based film can be developed for several applications, where one of them is to act as an antimicrobial packaging by nisin Z incorporation

Summary

Introduction

Food packaging is a great strategy to differentiate products in the market under consumers’ attention. There has been a noticeable increase in research on antimicrobial packaging to assure or improve the food quality These researchers have tended to study natural antimicrobials, such as bioactive compounds of vegetables and fruits; essential oils; and bacteriocins that are not adverse to consumers’ health (Mlalila, Hilonga, Swai, Devlieghere & Ragaert, 2018; Mulla et al, 2017; Niu, Liu, Song, Han & Pan, 2018; Pola et al, 2016; Sarwar, Niazi, Jahan, Ahmad & Hussain, 2018; Woraprayote et al, 2018). Nisin is a peptide composed by 34 amino acid units, presenting a cationic and hydrophobic character, and it is considered a lantibiotic. This bacteriocin is produced by species of Lactococcus lactis subsp. According to the active packaging concept, this work sets out to develop active films, incorporated with peptide nisin Z into HPMC matrix, to come up with a novel material that provides anti-

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