Journal: |
Ultrasonics Sonochemistry
Elsevier
|
Volume: |
|
Abstract: |
To study the impacts of thermosonication (TS), the spinach juice treated with TS (200 W, 400 W, and 600 W, 30
kHz, at 60 ±1
◦
C for 20 mint) were investigated for bioactive compounds, antioxidant activities, color properties, particle size, rheological behavior, suspension stability, enzymatic and microbial loads. As a result, TS
processing significantly improved the bioactive compounds (total flavonols, total flavonoids, total phenolic,
carotenoids, chlorophyll, and anthocyanins), antioxidant activities (DPPH and FRAP assay) in spinach juice.
Also, TS treatments had higher b*,L*, hue angle (h
0
), and chroma (C) values, while minimuma* value as
compared to untreated and pasteurized samples. TS processing significantly reduced the particle size, improved
the suspension stability and rheological properties (shear stress, apparent viscosity, and shear rate) of spinach
juice as compared to the untreated and pasteurized sample. TS plays a synergistic part in microbial reduction and
gained maximum microbial safety. Moreover, TS treatments inactivated the polyphenol oxidase and peroxidase
from 0.97 and 0.034 Abs min
1
(untreated) to 0.31 and 0.018 Abs min
1
, respectively. The spinach juice sample
treated at a high intensity (600 W, 30 kHz, at 60 ±1
◦
C for 20 mint, TS3) exhibited complete inactivation of
microbial loads (<1 log CFU/ml), the highest reduction in enzymatic activities, better suspension stability, color
properties, and highest bioactive compounds. Collectively, the verdicts proposed that TS processing could be a
worthwhile option to pasteurize the spinach juice to enhance the overall quality.
|
|
|