Evaluating the Efficacy of tannins from Psidium guineense Sw. leaves, Cinnamaldehyde, Eugenol, and Coconut Pairing Residue in Controlling Food Spoilage Fungal Growth

Abstract

There is a lot of interest in using natural alternatives for synthetic food additives including food preservatives. Research has been conducted to explore the antioxidant and antimicrobial properties of tannins from Psidium guineense Sw. leaves (PGSLT), the major components in cinnamon bark and leaf, namely cinnamaldehyde and eugenol, and the ethanolic extract of coconut pairing residue (CPRE). However, no studies have been conducted to evaluate their contribution to controlling fungal growth in food products. This study attempts to fill this gap by assessing the efficacy of PGSLT, Cinnamaldehyde(95%), Eugenol(95%), and CPRE in controlling the growth of fungi commonly involved in spoilage of baked foods. As test organisms, Rhizopus stolonifer, Mucor Sp, Aspergillus niger, and Fusarium Sp that are frequently found in baked foods were used. The Folin-Ciocalteu assay was used in this study to evaluate the total phenolic content of PGSLT and CPRE. For PGSLT, the concentration of tannin was 106.270.1 mg gallic acid eqv.g-1, whereas total phenol content of CPRE was 18.920.1 mg gallic acid eqv.g-1. The disc diffusion assay was employed to assess the inhibitory effect of PGSLT, Cinnamaldehyde, Eugenol, and CPRE against the fungal strains. For cinnamaldehyde(9.56 mmol/L, 10l) the diameters of inhibition zones of R.stolonifer, Mucor, A.niger, Fusarium were 14.00.1mm, 32.00.1mm, 13.00.1mm, 52.00.1mm respectively. For Eugenol(6.49mmol/L,10l) the diameters of inhibition zones of R.stolonifer, Mucor, A.niger, Fusarium cultures were 10.00.1mm, 12.00.1mm, 13.00.1mm, 16.00.1mm respectively. PGSLT and CPRE did not show any inhibitory activity. Interestingly, when cinnamaldehyde was combined with PGSLT or CPRE there was an enhancement of the inhibitory activity by approximately 30% (p<0.05). When eugenol was combined with PGSLT or CPRE there was an enhancement of the inhibitory activity by approximately 10% (p<0.05). The results of this study suggest that cinnamaldehyde and eugenol or combinations of cinnamaldehyde and eugenol with PGSLT or CPRE may be used to improve the shelf life of baked foods. Further studies will be carried out on synergistic enhancement of inhibitory activity and application of these natural substances in baked foods.