Assessment of Essential Oils as Biopreservative Agents for Artisanal Pineapple (Ananas comosus) Juice

Abstract

Background: The pineapple juice sold on the streets of Abidjan is a very popular drink among consumers. However, its physico-chemical and microbiological properties deteriorate rapidly after production, significantly limiting its shelf life. Aim: This study aimed to extend the shelf life of artisanal pineapple juice through the use of essential oils. Methodology: Samples of pineapple juice were collected from street vendors in Cocody (Côte d’Ivoire). Concentrations of 0.625 µL/mL, 1.25 µL/mL, 2.5 µL/mL and 5 µL/mL of the essential oils of lemongrass (Cymbopogon citratus), cinnamon (Cinnamomum verum), oregano (Origanum vulgare), savory (Satureja montana) and clove (Syzygium aromaticum) were added to the juices. The samples were stored at room temperature for seven days. The titratable acidity, total soluble solids (TSS) and the counts of mesophilic aerobic bacteria, yeasts, lactic acid bacteria, staphylococci and acetic acid bacteria were assessed. Results: Fresh pineapple juice had high initial microbial counts, with 7.57 log CFU/mL of mesophilic aerobic bacteria (MAB), 6.44 log CFU/mL of yeasts, 5.26 log CFU/mL of lactic acid bacteria, 5.18 log CFU/mL of acetic acid bacteria and 5.02 log CFU/mL of staphylococci. In the absence of a preservative, the yeast and lactic acid bacteria counts remained broadly stable during storage, whilst the acetic acid bacteria count increased significantly, reaching 8.41 log CFU/mL on the seventh day. Oregano essential oil proved particularly effective against lactic and acetic acid bacteria, whilst cinnamon and clove essential oils showed the greatest activity against yeasts. With the exception of 0.625 µL/mL of lemongrass, cinnamon, clove and 1.25 µL/mL of lemongrass, all other concentrations of the essential oils used were effective in maintaining the physico-chemical stability of pineapple juice during storage. Conclusion: These essential oils could therefore be used for the preservation of artisanal pineapple juice.