Antimicrobial Properties and Sensory Evaluation of Bread Enriched with Green Coffee Beans (GCB)

Abstract

Recently, the trend of enhancing daily consumed foods with functional ingredients has been increasing. Bread, being a food product, which is consumed regularly, contains most nutrients but lacks antioxidant rich polyphenolic compounds due to the usage of refined wheat flour. Green coffee beans (GCB) are known for their green colour, which is the colour of coffee beans prior to roasting. The aroma is described as mild, green, and bean-like, which deters many from trying to consume the product. This experiment is conducted to determine antimicrobial properties and the sensory response to study the physiological effect of caffeine in bread incorporated with GCB. The bread was baked with three (3) variable parameters which were: the concentration of GCB powder, baking time, and baking temperature. The effect of concentration of GCB powder, baking time, and baking temperature on bacteria growth were also observed. It is concluded that to control the bacteria growth, the optimum condition of incorporated bread was determined at baking temperature of 180.3°C, baking time of 39.9 minutes, and GCB powder concentration of 4.85 wt%. Sensory evaluation analysis for the optimised bread (enriched with GCB) and control bread (without GCB) were conducted by a series of sensory judges. The sensory evaluation determined the differences in all aspects of appearance, aroma, taste, and texture between the enriched and normal bread. The most significant differences are that the bread incorporated with green coffee bean was darker in colour, has more distinctive wood, caramel, and smoke smell, more pungent and less salty. In addition, it is also more bitter, and harder with a stronger aftertaste when compared to normal bread. In conclusion, bread enriched with GCB exhibits strong antimicrobial properties and acceptable differences in appearance, aroma, taste, and texture compared to normal bread.