Tempeh-Derived Savory Powders as Ingredients to Compensate Sodium Reduction in Vegetable Broth

Excessive sodium intake remains a major public health concern, yet reducing salt in savory foods often decreases consumer acceptance. This study evaluated tempeh-derived powders as natural flavor-enhancing ingredients for sodium reduction in vegetable broth. Four powder variants were prepared from laboratory-made tempeh: fresh tempeh powder (TP), overripe tempeh powder (OTP), roasted tempeh powder (RTP), and fried tempeh powder (FTP). These powders were incorporated into broth formulations with 20% and 30% sodium reduction, alongside full-salt and reduced-salt controls. Physicochemical analyses were conducted, and sensory evaluation was performed with 282 consumer panelists using consumer acceptance testing, perceived saltiness assessment, Rate-All-That-Apply (RATA), Just-About-Right (JAR), penalty analysis, and principal component analysis (PCA). Calculated added sodium decreased from 314.7 mg/100 mL in the full-salt control to 251.8 and 220.3 mg/100 mL in the 20% and 30% reduced-sodium controls, respectively. Tempeh powder addition significantly modified broth color and viscosity, while pH remained stable at 6.19-6.25. Total free amino-compound values increased markedly in tempeh-containing broths, with OTP showing the highest values at 245.6 and 242.2 mg glutamic acid equivalents/L in OTP_80 and OTP_70, respectively. Sensory results showed that OTP_80 achieved the highest overall hedonic score among reduced-sodium formulations and was significantly higher than CON_80 and CON_70 (p < 0.05). OTP_70 also maintained high overall liking and was not significantly different from the full-salt control. RATA and PCA indicated distinct sensory profiles among powder variants. These findings suggest that overripe tempeh powder may serve as a promising clean-label ingredient for sodium compensation in reduced-sodium savory broth.