Shelf Stability, Microbiological and Physicochemical Studies of ‘Zobo’ Drink Pasteurized and Treated with Preservative

Abstract

Background: The combined effect of pasteurization, improved hygiene and varied concentrations of sodium benzoate on the shelf stability and physicochemical attributes of ‘Zobo’ drink, a nutritious non-alcoholic indigenous beverage was evaluated. Objectives: To evaluate the combined effects of pasteurization, improved hygiene and food preservatives on the shelf stability of ‘Zobo’ drink. Methods: Freshly prepared ‘Zobo’ samples were aseptically dispensed in 100 mL capacity Polyethylene terephthalate (PET) bottles containing various concentrations of sodium benzoate (0.05%, 0.25%, 0.50%, 0.75% and 1.00%). Six ‘Zobo’ samples were produced from the fresh ‘Zobo’ using a modified method that combined Hurdle Technology and Hazard Analysis and Critical Control Points (HACCP) for preservation and stored for eight weeks on the shelf. Analyses were carried out weekly on loss in vitamin C content, microbial quality and physicochemical properties of the beverage for eight weeks. Results: Parameters analysed significantly (p<0.05) changed considering the methods of treatment and storage period. Pasteurization at 68^oC for 20 minutes eliminated successfully all pathogenic organisms and coliforms as none was isolated from the drink throughout the eight weeks of shelf study. Saccharomyces cerevisiae and Lactobacillus fermentum isolated from the samples during storage were responsible for the deterioration and spoilage of the beverage. Conclusion: Although the five different concentrations of the preservative used in combination with pasteurization were effective in extending the shelf life of the beverage, sample Bz 0.05% preserved better than all others without impacting negatively on the vitamin C content and other physicochemical properties of the drink.

Keywords: Zobo, Hibiscus sabdariffa, Sodium Benzoate, Pasteurization, shelf life