Effect of banana peel flour substitution on physicochemical properties, shelf life and sensory acceptance of wholemeal bread

Abstract

Banana fruits are highly consumed in Malaysia. Nevertheless, an issue of enormous disposal of banana peels should never be underestimated. Previous studies have shown that banana peels have high potential as functional ingredients to be added in a food product. This study was aimed to investigate the effect of different enrichment percentages of banana peel flour (BPF) on the properties of whole meal bread (WMB). Six different formulations of bread in total (3.5%, 7.0%, 10.5%, 14.0%, and 17.5%), along with control sample (0% BPF) were prepared. Physical properties including specific volume, color of crust and crumb and texture profile analyses were evaluated. Sensory acceptance test of the samples on several attributes such as color of crust and crumb, odor, porosity, taste, texture and overall acceptance was carried out. The nutritional properties were also assessed. Results showed that incorporation of BPF in WMB were significantly affecting (p<0.05) the color characteristics, specific volume and texture quality of WMB. BPF could be incorporated up to 7% without significantly affecting (p<0.05) the acceptance of crumb color, odor, and taste as well as overall acceptance of WMB. Meanwhile, there were significant changes (p<0.05) in terms of moisture, ash, protein, fat, crude fiber, total available carbohydrate and calorie content of WMB with increasing BPF substitution. Comparative study was done on control WMB and 7% BPF substituted WMB. Both were analyzed for their microstructure, total dietary fiber, antioxidant activity and microbiological shelf life. Sample with 7% BPF gave significantly lower (p<0.05) pore size, which resulted in denser structure. No significant difference (p>0.05) was observed on the inhibition activity of lipid peroxidation in both formulations after seven days of storage. The total dietary fiber content was higher (14.4%) in 7% BPF compared to control sample (11.3%). Similarly, the phenolic content was improved from 19.16±1.59 mgGAE/g in control sample to 36.06±1.90 mgGAE/g in sample with 7% BPF. However, incorporation of BPF could not give WMB a significantly longer shelf life. This study shows that banana peels have potentials to be added into healthy food products such as WMB, since it could improve the nutritional quality of WMB with satisfying sensory acceptance.