Synergistic Effect of Metagenome-Derived Starch-Degrading Enzymes on Quality of Functional Bread with Antioxidant Activity

Starch-degrading enzymes have gained particular importance in recent decades due to their crucial role in numerous industrial applications especially, in the bakery industry. In this study, a novel thermostable pullulanase (PersiPul1) is screened from the metagenomic data for improving the quality of functional bread. The novel PersiPul1 is active over a wide range of temperature (30-80 degrees C) and pH (4-9) and exhibits high thermal stability, retaining 58.70% of activity at 80 degrees C. A cocktail of thermostable pullulanase and alpha-amylase (PersiPul1and PersiAmy2) is developed to be used in bread fortified with quinoa protein (Chenopodium quinoa Willd). The bread fortified with 7% quinoa protein isolate possess the highest reducing power and ABTS (73.64%) and DPPH (72.27%) radical scavenging activities. The addition of the enzyme mixture decreases the hardness and chewiness of the bread. The porosity, specific volume, and browning index of bread with pullulanase and alpha-amylase are higher than control. Also, sensory analysis of the functional bread reveals higher scores in the presence of enzymes. Based on the results, the novel starch-degrading enzyme cocktail is a promising alternative for improving the physical and sensory characteristics of the antioxidant bread enriched with quinoa protein isolate to be used in the bakery industry as a potential bio-additive.

Automated summary

This study screened a novel thermostable pullulanase from metagenomic data to improve the quality of functional bread. A cocktail of thermostable pullulanase and alpha-amylase was developed to enhance the antioxidant properties and texture of quinoa protein-enriched bread, showing promising results in terms of physical and sensory characteristics.