Development and analytical characterization of turmeric-enriched coffee beverage.

Coffee, a widely consumed beverage rich in polyphenols, and turmeric (Curcuma
longa), rich in curcuminoids, can be combined to develop a functional beverage that blends
sensory appeal with health benefits. This study investigated the incorporation of turmeric
powder (T) and curcuminoid-rich turmeric extract (CE) into instant coffee at concentrations of
25, 50, 75, and 100 mg, and evaluated the resulting formulations for their physicochemical
characteristics, antioxidant activity, structural properties and sensory attributes.
Physicochemical evaluation showed pH ranging from 5.1–5.2 ± 0.01, titratable acidity 0.7–1.0
± 0.02 mL of 0.1 N NaOH, and total soluble solids 1.4–1.5 °Brix. However, CE showed a
noticeable colour change (L = 38.3 ± 0.02*) and increased turbidity (105.17 ± 3.79%). UPLC
analysis revealed elevated total curcuminoids in CE coffee (0.106 mg/mL) compared to T
coffee (0.0148 mg/mL). However, caffeine (0.37-0.38 mg/ml) and chlorogenic acid (0.57-0.58
mg/ml) contents remained unchanged among plain, T, and CE coffee, indicating that turmeric
addition did not affect the major coffee bioactive compounds. FTIR spectra showed
characteristic protein, carbohydrate, and polyphenol bands in coffee, while turmeric–coffee
blends exhibited increased intensity in curcuminoid-related regions, indicating preserved
structural integrity. Further, ABTS antioxidant activity remained comparable, with values of
5.73 ± 0.25 μmol/mL in T coffee and 7.10 ± 0.50 μmol/mL in CE coffee. GC–MS analysis
showed a richer volatile profile with higher furans (32.5%), pyrazines (18.3%), and phenolic
derivatives (12.7%), while sensory evaluation identified 100 mg of turmeric as the optimal
level, maintaining coffee’s physicochemical and sensory quality. These findings highlight the
potential of turmeric-enriched coffee as a novel nutraceutical beverage with added functional
benefits.