Antimicrobial properties of bioactive compounds of Indian spices and herbs in food – Food Science & Technology

Young Scientist, Postgraduate, winning article by Saravjeet Kaur Bajwa, Manchester Metropolitan University

Food safety has increasingly become a fundamental health concern for consumers and a major challenge for food manufacturers due to foodborne diseases outbreaks caused by pathogenic microorganisms ^[1]. In the process of combating the impact of foodborne microorganisms, there has been increased use of synthetic chemical preservatives such as nitrites, nitrates, benzoic acid as antimicrobial agents. Studies showed that nitrites, nitrates when used in processed meat and products causes increased risk of colon cancer^[2],^[3]. The utilisation of sulphites can result in allergic responses in sulphite sensitive persons. The use of synthetic phenolic antioxidants like butylated hydroxyanisole (BHA) and butylated hydroxytoluene (BHT) has been reduced, due to health risks concerns^[4]. Moreover, consumers are increasingly suspicious of synthetic preservatives and have increased desire for ‘CLEAN LABEL’. In the last decades, many research studies have focused on finding alternate antimicrobial agents for use in food to combat both pathogenic and spoilage microorganisms. Some of the studies have looked at potential bioactive compounds from natural plant based materials that could be used in food products, which inhibit growth of microorganisms and provide food safety and preservation effects^2,[5].

Plant sources of natural antimicrobials

A number of spices and herbs contain natural antimicrobial properties and can be used to extend the shelf life of unprocessed and processed foods by reducing microbial growth^[6],^[7],^[8]. Spices and herbs are natural plant materials, that are not only used as flavouring or colouring agents in food, but as standardised extracts for medicinal purposes, such as eugenol (from clove oil), and are also used in small quantities as preservatives in food^[9]. Application in the preservation of foodstuff is mainly through inhibition of lipid oxidation, colour loss and as retardants of microbial activity^2,5. Commonly used Indian spices and herbs are listed in Table 1.

Table 1 Some commonly used Indian spices and herbs

Common name	Biological name	Family	Part used
Bay leaves	Laurus nobilis	Lauraceae	Leaves
Black pepper	Piper nigrum	Piperaceae	Fruit
Cinnamon	Cinnamomum verum	Lauraceae	Bark
Cloves	Syzygim aromaticum	Myrtaceae	Flower buds
Coriander	Coriandrum sativum	Apiaceae	Seeds
Cumin	Cuminum cyminum	Apiaceae	Seeds
Mace	Myristica fragrans	Myristica	Aril (seed covering)
Nutmeg	Myristica fragrans	Myristica	Seed
Saffron	Crocus sativus	Iridaceae	Stigmas with style
Sesame seeds	Sesamum indicum	Pedaliceae	Seeds
Thyme	Thymus vulgaris	Lamiaceae	Leaves with flowering tips
Turmeric	Curcuma longa	Zingiberaceae	Roots

Bioactive components of spices and herbs

Spices and herbs contain secondary metabolites – a variety of bioactive compounds such as phenolic acids, flavonoids, and terpenes, which may be present in various parts of the plants such as flowers (jasmine, rose and lavender), buds (clove), leaves (thyme, bay leaves), fruits (star anise), twigs, bark (cinnamon), seeds (coriander, cardamom), wood (sandal), roots (ginger)^5,[10] imparting antimicrobial and antioxidant properties^2,5,[11]. Cinnamon, cloves, oregano, thyme and rosemary are some common spices with strong antimicrobial activity. The essential oil extracted from spices and herbs has shown antimicrobial activity inhibiting foodborne pathogens such as Listeria monocytogenes, Salmonella typhi, E.coli and Bacillus cereus in food as well as providing longer shelf life^1,3.

Essential oil composition depends on internal and external agents influencing the plant such as genetic structures, ecological situations and agricultural factors[12]. In addition, seasonal variations, developmental stages of collected plant material, methods of harvest, processing of plant material, such as extraction methods and the conditions of analysis, are influenced on the essential oil yield and on the composition of bioactive compounds^12,[13]. The active components including phenols, saponin, thiosulfinates, glucosinolates, alcohols, aldehydes, ketones, ethers and hydrocarbons especially in spices, for example, cinnamon, clove, garlic, mustard and onion show antimicrobial properties in inhibition of Gram-positive and Gram-negative pathogens¹ (Table 2).

Table 2 Bioactive (phenolic) components found in commonly used spices and herbs as a major antimicrobial compounds (Adapted from ^1,[14])

Category	Class	Sub-class	Example of spices and herbs
Polyphenols	Flavonoids	Flavanols (e.g. Catechin)	Cinnamon
		Flavanones	Fennel
		Flavones	Onion, Oregano
		Flavonols (e.g. Quercetin)	Coriander, Cumin, Black pepper, Onion
	Non- Flavonoids	Phenolic acids	Cloves
Terpenes	Limonene		Fenugreek, Mustard
Vanilloids	Curcumin		Turmeric, Ginger
Organosulphur compound	Disulfides, Thiosulfinates		Garlic, Onion

These bioactive components are responsible for antimicrobial action including degradation of the cell wall, disruption of the cytoplasmic membrane, leakage of cellular components, and destruction of protein². Figure 1 shows scanned electron microscopic (SEM) images of the effect of spice extract on Bacillus cereus and E.coli.

Antimicrobial properties of spices and herbs

Numerous studies have shown that cinnamon, which is the world’s most frequently consumed spice and has been granted generally recognised as safe (GRAS) status, is rich in bioactive compound such as cinnamaldehyde that possesses antimicrobial effects^1,14.

Tiwari et al.[15] reported that antimicrobial efficacy of spices extracts depends upon their chemical profile and concentration of bioactive components. Studies have shown that antimicrobial effects of essential oil extracts from spices and herbs have comparable effects to synthetic additives but their applications in the food industry has been limited due to their inherent characteristics, such as strong odour, flavour, aroma and relatively high cost¹. Research on essential oils of spices and herbs over the past few years are listed in Table 3.

Table 3 Research into essential oils of plant antimicrobials (spices and herbs) over 20 years

Spices and herbs	Applications	Effective against	Reference
Oregano, thyme, coriander	Effective antimicrobial components in essential oils (EOs) use in food preservation,	Enterobacteria, lactic acid bacteria, B. cereus, Pseudomonas spp; Bacillus cereus, Pseudomonas aeruginosa, E.coli, Listeria monocytogenes	Almajano et al.^[16] Gutierrez et al.^[17]
Cinnamon, cloves, cumin	EOs showed strong antimicrobial effect, Food flavouring and preservation	Staphylococcus aureus, Klebsiella pneumonia aeruginosa, E. coli; Bacillus cereus, L. monocytogenes, Pseudomonas fluorescens, Salmonella enteritidis	Ceylan and Fung^[18] Agaoglu et al.^[19] Wei et al.⁹
Bay leaves, coriander, cinnamon, thyme	Effective antimicrobial properties for pathogenic spoilage microorganisms	Bacillus subtilis, E.coli, L. monocytogenes, Salmonella typhimurium, Staphylococcus aureus	Burt⁵ Gutierrez et al.¹⁷ Bajpal et al.^[20]
Thyme, cinnamon, clove	Effective essential oil components	Bacillus cereus	Davidson and Naidu^[21]

Future of antimicrobial agents in food

Studies showed that the addition of spice extracts could effectively retard microbial growth, reduce lipid oxidation, maintain or improve sensory attributes and extend the shelf life of food during storage^1,5,[22]. Several studies showed that spice extracts have antimicrobial, antioxidant properties^1,5. The bioactive components in spice extract could be relevant to use as natural antimicrobial alternatives to synthetic chemical preservatives in food safety and preservation.

With thanks to supervisors – Dr Tristan Dew, Dr Nessar Ahmed, Dr Daniel Anang, Department of Health Professions, Manchester Metropolitan University, UK.

References

1. Tajkarimi, M. M., Ibrahima, S.A. and Cliver, D.O. (2010). ‘Antimicrobial herb and spice compounds in food.’ Food Control, 21 pp. 1199–1218.

2. Witkowska, A.M., Hickey, D.K., Gomez, M.A. and Wilkinson, M (2013). ‘Evaluation of antimicrobial activities of commercial herb and spice extracts against selected food-borne bacteria.’ Journal of food research, 2 (4).

3. Weerakkody, N. S., Caffin, N., Turner, M. S. and Dykes, G. A. (2010). ‘In vitro antimicrobial activity of less-utilized spice and herb extracts against selected food-borne bacteria.’ Food Control, 21(10) pp. 1408-1414.

4. Pisoschi, A. M., Pop, A., georgescu, C., Turcus, V., Olah, N. K. and Mathe, E. (2018). ‘An overview of natural antimicrobials role in food – review article.’ European journal of Medicinal Chemistry, 143 pp. 922-935.

5. Burt, S. (2004). ‘Essential oils: Their antibacterial properties and potential applications in foods– A review.’ International Journal of Food Microbiology, 94(3) pp. 223–253.

6. Ahmad M.S., Pischetstrieder M. and Ahmed N (2007). ‘Aged garlic extract and S-allyl cysteine prevent formation of advanced glycation endproducts.’ European Journal of Pharmacology, 561 pp. 32-38.

7. Tiwari, B. K. (2015). ‘Ultrasound: A clean, green extraction technology.’ Trends in Analytical Chemistry, 71 pp. 100–109.

8.Tajkarimi, M. M., Ibrahima, S.A. and Cliver, D.O. (2010). ‘Antimicrobial herb and spice compounds in food.’ Food Control, 21 pp. 1199–1218.

9.Wei, M. C., Xiao, J. and Yand, Y. C. (2016). ‘Extraction of α-humulene-enriched oil from clove using ultrasound-assisted supercritical carbon dioxide extraction and studies of its fictitious solubility.’ Food chemistry, 210 pp. 172-181.

10. Asbahani, A. E., Miladi, K., Badri, W., Sala, M., Addi, E. H. A., Casabianca, H., Mousadik, A. E., Hartmann, D., Jilale, A., Renaud, F. N. R. and Elaissari, A. (2015). ‘Essential oils: From extraction to encapsulation.’ International journal of pharmaceutics, 483 pp. 220-243.

11. Zheng, W. and Wang, S. Y. (2001). ‘Antioxidant activity and phenolic compounds in selected herbs.’ Journal of Agricultural and Food Chemistry, 49 pp. 5165–5170.

12. Moghaddam, M., Miran, S. N. K., Pirabalouti, A. G., Mehdizadeh, L. and Ghaderi, Y. (2015). ‘Variation in essential oil composition and antioxidant activity of cumin (Cuminum cyminum L.) fruits during stages of maturity.’ Industrial crops and products, 70 pp. 163-169.

13. Hussain, A. I., Anwar, F., Sherazi, S. T. H., and Przybylski, R. (2008). ‘Chemical composition, antioxidant and antimicrobial activities of basil (Ocimum basilicum) essential oils depends on seasonal variations.’ Food Chemistry, 108 (3), 986-995.

14. Bi, X., Lim, J. and Henry, C. J. (2017).’Spices in the management of diabetes mellitus – review.’ Food Chemistry, 281-293.

15. Tiwari, B. K., Valdramidis, V., Donnell, C., Muthukumarappan, K., Cullen, P. and Bourke, P. (2009). ‘Application of natural antimicrobials for food preservation.’ Journal Agricultural Food Chemistry, 57 (14) pp. 5987-6000.

16. Almajano, M. P., Carbo, R., Lopez Jimenez, J. A., and Gordon, M. H. (2008). ‘Antioxidant and antimicrobial activities of tea infusions.’ Food Chemistry, 108 (1) pp. 55–63.

17. Gutierrez, J., Barry-Ryan, C., and Bourke, P. (2008a). ‘The antimicrobial efficacy of plant essential oil combinations and interactions with food ingredients.’ International Journal of Food Microbiology, 124(1) pp. 91–97.

18. Ceylan, E., and Fung, D. Y. C. (2004). ‘Antimicrobial activity of spices.’ Journal of Rapid Methods and Automation in Microbiology, 12(1) pp. 1–55.

19. Agaoglu, S., Dostbil, N. and Alemdar, S. (2007). ‘Antimicrobial activity of some spices used in the meat industry.’ Bulletin of the Veterinary Institute in Pulawy, 51, pp. 53–57.

20. Bajpai, V. K., Rahman, A., and Kang, S. C. (2008). ‘Chemical composition and inhibitory parameters of essential oil and extracts of Nandina domestica Thunb. to control food-borne pathogenic and spoilage bacteria.’ International Journal of Food Microbiology, 125(2) pp. 117–122.

21. Davidson, P. M. and Naidu, A. S. (2000). ‘Phytophenols.’ In A. S. Naidu (Ed.), Natural food antimicrobial systems (pp. 265–295). Boca Raton, Florida: CRC Press.

22. Krishnan, K.R., Babuskin, S., Babu, P. A.S., Sasikala, M., Sabina, K., Archana, G., Sivarajan, M., Sukumar, M. (2014). ‘Antimicrobial and antioxidant effects of spice extracts on the shelf life extension of raw chicken meat’. International Journal of food microbiology, 171 pp. 32-40.