Abstract:
Background: Plant-based milk including soy milk, is a fast-growing trend in the dairy industry.
The global instant tea powder (ITP) market is getting recognized as a convenient beverage
solution. However, ITP with plant-based milk has not evolved considerably.
Objective: To compare the physiochemical, techno and bio-functional, sensory properties, and
microbial quality of freshly prepared soy milk ITP with full cream milk and skim milk ITP using
standard methods
Methods: Soy milk was prepared using soybeans. Homogeniser was employed in the fat
standardization of cow milk. Proximate composition (moisture, fat, protein, % total carbohydrate),
other physiochemical properties (solid non-fat content, color, pH, titratable acidity, water activity,
viscosity, specific gravity), techno-functional properties (bulk density, tapped density, flowability,
wettability, insoluble index, solubility), total phenolic contents and microbial quality of spray
dried ITPs were evaluated by standard methods. The Fourier transform infrared spectroscopy
(FTIR) was performed to determine compositional variations among samples. Sensory analysis
was performed using 30 untrained panelists.
Results: The results demonstrated the protein percentage was highest in soy milk ITP
(57.12±0.02) followed by skim milk ITP (21.34±0.03) and full cream ITP (13.64±0.03). The fat
percentage of soy milk ITP (3.22±0.01) was significantly lower compared to full cream ITP
(13.19±0.11). Soy milk ITP had the highest viscosity (11.53±0.13 cP), highest titratable acidity
(0.13±0.01), and lowest pH (6.11±0.11) values. Among the three samples, overall sensory
acceptability was highest in skim milk ITP, and remain samples did not show a significant
difference. Soy milk ITP showed the least preference for aroma, taste, and aftertaste. FTIR
analysis showed the main compounds of all three samples are almost similar. The total phenolic
content of soy milk ITP was the highest (25±0.59 GAE mg/100g). Best rehydration properties
were observed in full cream milk ITP followed by soy milk ITP. These properties were improved
by mixing whole milk powder with soy milk powder. The microbial counts of the powders were
within acceptable limits.
Conclusions: Soy milk can be utilized to formulate ITP as a healthy alternative to full cream and
skim milk ITP. The techno-functional properties can be enhanced by mixing soy milk with full
cream milk powders.
