Discrimination of Defective (Full Black, Full Sour and Immature) and Nondefective Coffee Beans by Their Physical Properties

Abstract

AbstractIn this research the physical properties of defective and nondefective coffee beans were investigated. The study results show that there are highly significant differences (P < 0.001) in the physical properties (true and bulk volume, true and bulk density, mass) and (P < 0.05) in sphericity and porosity of green coffee beans, respectively. Higher and lower values of mass and dimensional parameters were obtained in full sour and full black coffee beans, respectively. On the other hand, the physical properties of the beans investigated as the function of moisture content (%db) were found to be a linear relation with volume, mass and equivalent diameter, and an inverse relation with density of the beans. Generally, the moisture content (% dry basis [d.b.]) of defective beans (full sour 12.87%, immature 11.34%, full black 10.41%) is higher than nondefective beans (10.22%) for sample kept at oven temperature (105C) for 48 h. The results of the study indicated that the physical properties alone can successfully separate defective and nondefective beans prior and after roasting.Practical ApplicationsThe physical properties of defective and nondefective coffee beans were investigated. The determined physical properties of beans have useful applications in coffee quality control. In addition, these properties have significant importance for machinery and process equipment design. The methods are simple, fast and inexpensive as compared with the chemical methods that need high‐cost equipment and solvents.