Jacobs Journal of Food and Nutrition

Preserving Quality and Nutrient Value of Blackberries by Essential Oil Wash and Vapor Treatments

*Tony Z Jin
Department Of Agricultural Sciences, Eastern Regional Research Center, Agricultural Research Service, USDA, 600 East Mermaid Lane, Wyndmoor, PA 19038, United States

*Corresponding Author:
Tony Z Jin
Department Of Agricultural Sciences, Eastern Regional Research Center, Agricultural Research Service, USDA, 600 East Mermaid Lane, Wyndmoor, PA 19038, United States
Email:tony.jin@ars.usda.gov

Published on: 2019-07-29

Abstract

Blackberries have a short life as they are highly susceptible to contamination of spoilage microorganisms. In this study, two essential oils were used to treat fresh blackberries for the extension of shelf-life. The application methods of essential oils on blackberries that were evaluated included: (1) Carvacrol (COL) used as a wash solution, (2) ally isothiocyanate (AIT) used as a vapor, and (3) COL wash followed by AIT vapor treatment (COL+AIT) was also investigated. The survival of total bacterial populations, yeast and mold populations, respiration rate, and quality and nutrient changes were determined during 12 d storage at 10° C. The washing treatment reduced microbial loads by 2 logs initially but could not inhibit their outgrowth during storage, while AIT vapor treatment and the combination of COL wash and AIT vapor treatment completely inhibited the growth of bacteria and mold and yeast. AIT vapor alone or in combination with COL wash significantly reduced the respiration rate of blackberries, hence, maintaining the quality and nutritional values through 12 d storage. The results suggest that the combination of COL washing and AIT vapor is not necessary and AIT vapor treatment alone appears to be very promising for extending the shelf-life of blackberries.

Keywords

Blackberries; Quality; Nutrition; Essential oils; Wash; Vapor

Introduction

Blackberries have a sweet, tart flavor, and are also rich in vitamins and antioxidants. They are consumed in foods such as salads, fruit smoothies, juices and yogurt. However, blackberries are highly perishable, and up to 40% of blackberries are lost from the post-harvest stage to the time they appear on the market due to improper handling. Most blackberries destined for sale on the fresh market become unmarketable after two to three days due to decay. In addition, possible pathogenic contamination is also a food safety concern since they are eaten fresh. Standard small fruit production practices discourage growers from washing these fruits during the post-harvest stage. The presence of water on the sur-face of small fruits may promote the growth of pathogenic bacteria, increasing the risk of foodborne disease. It is necessary to develop an intervention method which inactivates populations of undesirable microorganisms and preserves the nutritional attributes of blackberries.