Clean-label alternatives for food preservation: An emerging trend

Consumer demand for natural or 'clean-label' food ingredients has risen over the past 50 years and continues growing. Consumers have become more aware of their health and, therefore, insist on transparency in the list of ingredients. Preservatives are the most crucial food additives, ensuring food safety and security. Despite tremendous technological advancements, food preservation remains a significant challenge worldwide, primarily because most are synthetic and non-biodegradable. As a result, the food industry is placing more value on microbiota and other natural sources for bio-preservation, leading to the substitution of conventional processing and chemical preservatives with natural alternatives to ensure 'clean-label.' General Standard for Food Additives (GSFA) includes some of these 'clean-label' options in its list of additives. However, they are very rarely capable of replacing a synthetic preservative on a 'one-for-one' basis, putting pressure on researchers to decipher newer, cleaner, and more economical alternatives. Academic and scientific research has led to the discovery of several plant, animal, and microbial metabolites that may function as effective bio-preservatives. However, most have not yet been put in the market or are under trial. Hence, the present review aims to summarise such relevant and potential metabolites with bio-preservative properties comprehensively. This article will help readers comprehend recent innovations in the 'clean-label' era, provide informed choices to consumers, and improve the business of regulatory approvals.

Relationship between volatile components, antimicrobial and antioxidant properties of the essential oil, hydrosol and extracts of Citrus aurantium L. flowers

INTRODUCTION

In the Mediterranean Region, essential oil, hydrosol, and ethanol extract of C. aurantium flowers have a long history of usage in different products such as a flavoring agent and an ingredient of many traditional anti-infectious and skin care products. The present study was undertaken to compare the antimicrobial activity, antioxidant activity and phytochemical composition of essential oil (EO), hydrosol and ethanol extract of Cyprus Citrus aurantium L. flowers.

METHOD

The chemical composition of samples was determined by GC/MS. The total phenolic and flavonoid contents were determined by Folin-Ciocalteu colorimetric method and aluminum chloride colorimetric assay, respectively. Antioxidant activity was evaluated by 1,1-diphenyl-2-picrylhydrazyl (DPPH) and hydrogen peroxide (H₂O₂). The antimicrobial activity of the samples was determined by disc diffusion and broth microdilution methods against five foodborne pathogenic bacteria.

RESULT

The EO and ethanol extract showed significant antimicrobial activity against all tested pathogens which were attributed to the presence of important phytochemical classes such as polyphenols, flavonoids, alkaloids, and terpenes. The EO showed higher antimicrobial activity followed by ethanol extract with minimum inhibitory concentrations ≤1562mg/l and ≤6250mg/l, respectively, against Amoxycillin resistant Bacillus cereus and other test organisms. Significantly (p≤0.05) the higher total phenolic (81.37mg GAE/g) and flavonoid contents (20.34mg QE/g) were obtained in the ethanol extract with the higher antioxidant activity as compared to EO and hydrosol with half maximal inhibitory concentration (IC₅₀) values of 96.07μg/ml in the DPPH and 66.50μg/ml in the H₂O₂ assay. A significant correlation (R²≥0.94) was found between phenolic content and IC₅₀ values for DPPH and H₂O₂ assays. β-Cholesta-5,22-dien-3-ol, herboxide isomer and isochiapin-B are reported for the first time for essential oil.

CONCLUSION

Citrus aurantium L. flowers have strong potential for the isolation of antimicrobial and antioxidant agents for further use in food and medicine industries as natural preservatives.