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