Effect of fermentation modification using tempeh starter on the physical, functional, and pasting properties of sorghum flour (<i>Sorghum bicolor</i> L.)

Abstract Sorghum flour is currently popular in various food products, however, its usage remains limited. This is primarily due to its lack of gluten, high levels of amylose and fiber, darker color, unique taste and aroma, and rough, sandy texture. The objective of this study was to assess the physical, functional, and pasting properties of modified sorghum flour by fermentation with tempeh starter. The study involved four starter concentration treatments: 0%, 2%, 4%, and 6%. The resulting sorghum flour was then assessed for color, fineness modulus, water absorption, solubility, swelling power, syneresis, and starch gelatinization characterization. The findings demonstrated that the addition of tempeh starter concentration significantly influenced (P&lt;0.05) the physical characteristics of sorghum flour. The color of sorghum flour became brighter, with the highest L* value recorded at 80.40 and a whiteness index of 78.80. Additionally, the texture of modified sorghum flour became smoother, with a low fineness modulus of 0.25. Moreover, the water absorption capacity increased until it reached 283.03% with a solubility of 90%. Fermentation also has a significant effect on the characteristics of starch gelatinization, except for breakdown viscosity and peak time. It is hoped that the results of this research will lead to the replacement of wheat in various food product applications, particularly in noodle and bakery products.