Pineapple leaf juice characterization and evaluation of factors affecting microbial growth inhibition

Abstract

Pineapple leaves were used in this study to characterize and investigate the factors influencing the inhibition of microbial growth using its juice. Ultra-performance liquid chromatography to quadrupole time-of-flight mass spectrometry was used to study the phenolic compounds present in pineapple leaf juice. Methyl-5-O-caffeoylquinate, octahydrocurcumin, meliadanoside A, stilbostemin D, feralolide, agrimol C and kukoamine A were found to be the most prominent phenolic in pineapple leaf juice. The four factors of 0.5–5 h of microbial inhibition time, 0.2563–0.5127 mg GAE/mL of total phenolic content concentration in pineapple leaf juice, 26–37 °C of temperature and 1:1 and 1:3 of pineapple leaf juice-to-microbe ratio were investigated using a factorial analysis. The microbial inhibition growth up to 21.74% were obtained under inhibition time of 0.5 h, 0.5127 mg GAE/mL of total phenolic content concentration in pineapple leaf juice, temperature of 37 °C and 1:1 pineapple leaf juice-to-microbe ratio. Temperature was the greatest contributor (1.56%) to inhibit microbial growth, accompanied by total phenolic content concentration in pineapple leaf juice with 1.27%, microbial inhibition time with 1.07% and pineapple leaf juice-to-microbe with 0.29%. This study demonstrated the potentials of pineapple leaf as a valuable source of natural products with microbial inhibitor properties, making it one of the greener and more cost-effective alternatives to expensive synthetic agents for controlling microbial growth.