Essential oils and other natural products for the preservation of shredded carrots

Abstract

A great interest on the investigation of natural products (i.e., essential oils-EOs, organic acids, and edible coatings) as postharvest sanitizers has been noticed in an attempt to minimize the use of chemical synthetic compounds (i.e., chlorine) in the food industry. This work aims to present the outcomes of natural products application (essential oils, hydrosols and ascorbic acid) on shredded carrots quality with two separate experiments. The application of mint EO, mint hydrosol (Hyd) and pomegranate juice on shredded carrots inoculated with human foodborne pathogens (Escherichia coli, Listeria monocytogenes) decreased both bacterial populations. Mint EO was found to decrease polyphenols and antioxidants, whereas an increase was observed with pomegranate juice and mint Hyd. In another experiment, marjoram EO (1:1500 v/v), marjoram Hyd (1:15 v/v), ascorbic acid (AA, 1% w/v) and their combinations when applied on shredded carrots revealed that EO and AA were able to preserve the product (acceptable aroma and bright orange color), while marjoram Hyd resulted in darker (brown) color. Moreover, the combinations of AA with marjoram EO and hydrosol (EO+AA, Hyd+AA) were found to increase shredded carrot's total carotenoid content. All applied single or combined treatments decreased the microbial load, while AA increased total phenols and antioxidants of shredded carrots. Single and/or combined natural products can be considered as promising alternative sanitizing agents used in the food industry, as long as the optimum scenarios (concentration, time and method of application) are investigated for each produce.