The Antimicrobial Efficacy and Quality Changes in Pineapple Juice Treated with Natural Preservatives
Theresa Onyeka Obe *
Department of Food Science and Technology, College of Food Technology, University of Agriculture, Makurdi, Benue State, Nigeria.
Julius Amove
Department of Food Science and Technology, College of Food Science and Human Ecology, Joseph Sarwuan Tarka University, Makurdi, Benue State, Nigeria.
Mike Ojotu Eke
Department of Food Science and Technology, College of Food Science and Human Ecology, Joseph Sarwuan Tarka University, Makurdi, Benue State, Nigeria.
*Author to whom correspondence should be addressed.
Abstract
The study investigated effects of natural preservatives on the quality of fresh pineapple fruit juice. The natural preservatives used are ginger, garlic, moringa seed and cloves and were processed into powder. The treatment of pineapple with the natural preservatives was at a concentration of 20% with 3 minutes dipping time. The enumeration and identification of microorganisms on the fresh pineapple fruit, shows that the total bacteria count was 1.8×105 colony forming unit per gram (CFU/g) and 4.6×103 CFU/g respectively. The identified bacteria are staphylococcus aureus and streptococcus spp and identified fungi were Aspergillus Niger, penicillin spp and Aspergillus perfrigens respectively. Moringa seed extract exhibited moderate antibacterial activity, with zones of inhibitions (ZOIs) of 16 mm against Staphylococcus aureus and 15 mm against Streptococcus spp. Garlic (GL) showed the least antibacterial activity among the natural preservative samples, with 9mm zones of inhibition against Staphylococcus aureus and 4 mm against Streptococcus spp. Clove extract displayed significant antibacterial activity, with 14 mm zones of inhibition against Staphylococcus aureus and 19 mm against Streptococcus spp. Ginger extract exhibited slight antibacterial activity, with zones of inhibition of 4 mm against both bacterial strains. Chemical composition of the treated pineapple juice result ranges from 0.77-0.865% TTA, 64.12-63.10 Vit C, 26.50-25.06 Brix Content,3.20-3.39 pH and 13.23-13.17 TSS respectively. The control (100% pineapple Juice) displayed balanced properties serving as an effective baseline3. Storage studies, ambient stored samples were analyzed at 0 day and 21 days intervals. All samples were subjected to standard analytical methods. Results showed increase in number of bacteria and fungi with increase in the number of days. The use of cloves, garlic, ginger, and moringa seeds as natural antimicrobial agents in pineapple juice is effective in controlling microbial growth, thus enhancing the safety and shelf life of the juice. These treatments also influence the chemical and sensory properties of the juice, contributing to consumer acceptability.
Keywords: Pineapple, antimicrobial, storage stability, zones of inhibition