Bioactivities of Spices and The
Effects of Different Cooking Methods
Assist. Prof. Eric Chan Wei Chiang
Spices
With a history as long as human
civilization, spices have inspired war,
exploration and trade
Many spices used in traditional
medicine have been shown to have
bioactive properties
The effects of cooking on these
bioactivities have not been
investigated and there is little on
the anti-tyrosinase and anti-quorum
sensing properties of spices
Sun drying and thermal
treatment
Traditionally, spices are sun dried as a
means of preservation
However, sun drying is very dependent
on the weather and slow drying may
result in losses from the growth of mold
This has led to the use of various
thermal drying techniques. Our study
examines the effect of heat on the
bioactive properties of spices
Spices studied Twelve spices were screened for phenolic contents
and antioxidant activities.
The spices were basil, black pepper, cardamom,
cinnamon, clove, coriander, cumin, fennel,
fenugreek, mustard, poppy and star anise
Antioxidant content
Total phenolic content (TPC)
Total flavonoid content (TFC)
Caffeoylquinic acid content (CQAC)
Antioxidant activity
DPPH Radical Scavenging (AEAC)
Ferric reducing power (FRP)
Ferrous ion chelating (FIC)
Antibacteria, anti-tyrosinase
and anti-QS inhibition
Disc diffusion assay
DOPA chrome method
Violacein inhibition
Cooking methods
Microwave
Boiling and blanching
Best antioxidant properties
Out of the twelve spices studied, the five
shown above had the highest phenolic
content and primary antioxidant activity
Ferrous ion chelating as indicated by the
CEC50 is a secondary antioxidant activity
that does not correlate with phenolic
content
Effect of cooking on
antioxidant properties
Clove and cardamom
showed an increase in total
phenolic content and
radical scavenging after
thermal treatment
Phenolics were leached by
water used by boiling and
blanching to different
degrees in different herbs
Heat treatment releases
bound phenolics but is
offset by thermal
degradation and leaching
Effect of cooking on
tyrosinase inhibition
Cinnamon and cumin had the highest tyrosinase
inhibition with potential to be applied in skin-
whitening
In most cases, heating does not affect tyrosinase
inhibition
Tyrosinase inhibition often attributed to phenolic
compounds but the type of phenols is more
important than quantity
Effect of cooking on
antibacterial properties
Clove showed broad-spectrum antibacterial activity
against all six bacteria
Cooking had a variable effect on antibacterial activity
Interestingly, cinnamon only inhibited Gram-negative E.
coli after cooking
Effect of cooking on quorum
sensing inhibition
Of all the herbs studied, only clove and cinnamon
showed anti-QS activity that is not affected by cooking
Anti-QS compounds inhibit the bacteria cell to cell
communication and could inhibit virulence genes in
some pathogens
This could be developed into a non-bactericidal therapy,
thus negating antibiotic resistance
Summary
Cooking and by extension, thermal
treatments could release addition
phenolic compounds
This increase antioxidant activity and in
some cases, anti-tyrosinase and
antibacterial activity
What about non-thermal drying methods?
How do they affect phenolic compounds?
Freeze-drying enhanced the
AOP of leaves of E. elatior
The antioxidants within the
leaves were not heat stable
The HPLC chromatogram of
freeze-dried leaves of E.
elatior showed greater
amounts of minor compounds
than fresh leaves
Etligera elatior
Overlay of chromatograms
showed greater amounts of
minor compounds in freeze-
dried than fresh leaves.
BUT: Freeze-drying does not inactivate polyphenol oxidase in
leaves and phenols may be oxidised upon rehydration
Relevant articles
Effects of different cooking methods on the bioactivities of
some spices
http://dx.doi.org/10.9755/ejfa.2015.04.069
Antioxidant properties of herbs with enhancement effects of
drying treatments: A synopsis
http://dx.doi.org/10.1016/j.fra.2013.02.001
Potent quorum sensing inhibition by methyl gallate isolated
from leaves of Anacardium occidentale L. (cashew)
http://it.science.cmu.ac.th/ejournal/dl.php?journal_id=5952
Thank youSlides can be downloaded here:
www.slideshare.net/ChanEWC