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#4. On Spices

Herbs and spices have seen a significant increase in their use during the 21st century. People have always been searching for new ways to spice up their lives, looking for new experiences, products, flavors, and spices. This trend increased during the pandemic, as people needed to hunker down at home and then cook food and introduce variety, color, and new flavors through spicing. 

As people botanists, our best way to improve people’s experiences is to link that desire for new things with the remarkable plant diversity.

My passion is to study the chemistry and quality of new, forgotten spices, especially from Africa.

In 2012, I led an ethnobotanical project entitled “An Ethnobotanical Survey and Value Chain Study” to survey the plants used by Liberians, with the idea to contribute to their commercialization and provide income to Liberian communities. The West African people used many of these spices, including West African black pepper, grains of paradise, and Xylopia.  

Grains of paradise

Grains of paradise (Aframomum melegueta) is a member of the ginger family (Zingiberaceae), originated from West Africa, specifically, the countries of the Guinea forest, Ghana, and Liberia. 

Grains of paradise are a seed spice, like cardamom, while ginger is an underground rhizome and not a root! They are monocots, with the characteristic palmated leaves and red fruits sprouting from the ground. When mature, they are harvested, dried, and pounded to remove the seeds within the fruit. The seeds are tiny, around 4mm round, with brown-reddish tints. When the seeds are crushed, the white endosperm is revealed, and they release a spicy aroma, resembling that of black pepper. Compared with black pepper, the flavor of grains of paradise is mild.

I conducted a chemical analysis of the seeds to learn more about the flavor components. 

The non-volatile components are similar to ginger’s, with a different volatile profile. 

The sesquiterpene alpha humulene dominates the aroma profile. 

Gingerols compose the non-volatile fraction of the seed that gives the spice its flavor. 

Gingerols, antioxidant polyphenols, are also found in ginger.  When I started the research in the 2000s, this spice was almost unknown I led a publication of the article “Chemistry, quality and functional properties of Grains of Paradise (Aframomum melegueta), a rediscovered spice” where I describe the chemistry and develop trade standards to contribute to its commercialization. This year (2022), we just published a new paper on grains of paradise, as its extracts are bioactive against COVID. This research was an opportunity to study in more detail the profile of the non-volatile components, the gingerols, that confirm its presence in grains of paradise. 

This spice is now becoming common in online stores, such as eBay, Etsy, Amazon, and others, where they can be purchased. I used the spice in the kitchen, and its mild spiciness and aroma make it a perfect match for red meats.

Xylopia aethiopica

Another West African spice is Xylopia aethiopica, a small tree that bears the fruit similar to a bean. It is a pod with a string of seeds with a hardened cover (Fig. 1). When mature, the pods are green, turning dark brown, almost black, when dried. 

Figure 1. The pods of Xylopia (Xylopia aethiopica).

Essential oils dominate the flavor profile, the main component is 1,8 cineole or eucalyptol, which gives the spice a fresh, somewhat minty aroma. I also led the publication of an article, to study chemistry and develop trade, quality standards. Recently, with the help of graduate and undergraduate students, we published an article on finding new uses for the spices, as the seeds can be separated from the pods, and the seeds can be the actual product of commerce. Then the seeds can be used alone or as part of spice medleys.

We ground the pods into a powder and added them to coffee before brewing. The results were surprising, a coffee with a unique woody and fresh aroma.

West African black pepper (Piper guinensee)

The West African black pepper is another example of a forgotten and really interesting new spice. Piper guinensee, a relative to the common black/white pepper P. nigrum, grows in the Guinea forest of Liberia, its peppercorns are smaller than the regular pepper, the amount of the active principle piperine is lower. The aroma of the spices is unique as it has floral notes, and mild flavor. We have yet to see this spice in the marketplace. The research and purpose of my blog have been to highlight the benefits of these new natural products, I am contributing to generate interest in their commercialization. Hopefully, they will be available in the following years. CORRECTION! This spice is available on the internet!

Spice Medleys and South American Spices

Talking about spice medleys, some companies are selling mixtures of several spices in containers with a grinder, and such mixtures can contain whole seed spices and other parts coming from, among many others, black pepper, white pepper, red pepper, allspice, coriander, and tree pepper (Fig. 2). 

The tree pepper caught my attention as it reflects the need for new flavors. The pepper tree is a South American tree. There are many species, some of the species used in commerce include Schinus molle and S. terebinthifolia. The tree bears small, round, red fruits produced from multiple flowers or inflorescences. The seeds are harvested, dried, and then ground and used as a spice to add flavor to any food, such as soups, meats, and salads.

Figure 2. Spice peppercorn medley, containing different types, such as black, white and green peppercorns (Piper nigrum), pink peppercorns (Schinus sp.), coriander seeds (Coriandrum sativum) and allspice.

Mexican Oregano

The Mexican Oregano, Lippia graveolens, a member of the Verbenaceae family,  is a spice that grows wild in northern Mexico and the southern US. As the regular oregano (Origanum vulgare), the ground leaves are used as a spice. The essential oils give foods a unique flavor, a sort of blend between oregano and thyme (Thymus vulgaris). The chemical profile of the Mexican oregano is closer to thyme than oregano. This is how this Mexican spice got its name.  

This is an ongoing topic, with more coming later. 

References

2020. Adolfina R. Koroch, H. Rodolfo Juliani. Biological activities and chemistry of secondary metabolites of grains of paradise (Aframomum melegueta).  In: African Natural Plant Products Volume III: Innovation in Chemistry, Health and Nutrition applications. American Chemical Society (ACS) Symposium Series. ACS, Washington D.C. Chapter 6, 139-151 DOI: 10.1021/bk-2020-1361.ch006

2020.  Larry Hwang, Laura Merja Merja, Jim Simon, and Hector R. Juliani. Developing New Natural Plant Products from the Spice Xylopia aethiopica from Ghana and Liberia. Journal of Medicinally Active Plants 9, (1). DOI: https://doi.org/10.7275/dyvk-nz78

2013. H. R. Juliani, J. E. Simon, L. Amekuse, J. Asante-Dartey, P. Man-Yeboah, A. B. Okrah. Non-Timber Forest Products Value Chain Study. In PROSPER communities of Nimba and Grand Bassa, Liberia. Technical Report Prepared for USAID/PROSPER. Monrovia. Liberia.

2013. Juliani, H. R., A.R. Koroch, L. Giordano, L. Amekuse, S. Koffa, D. Acquaye and J.E. Simon. Piper guineense (Piperaceae): Chemistry, Traditional Uses and Functional Properties of an “African Black Pepper”. In: African Natural Plant Products Volume II: New Discoveries in Chemistry, Health and Nutrition. American Chemical Society (ACS) Symposium Series 1127. ACS, Washington D.C. Chapter 3, pp 33-48.

2008. H.R. Juliani, C. WelchG, J. Asante-Dartey, M. Wang, J.E. Simon. Chemistry, quality and functional properties of Grains of Paradise (Aframomum melegueta), a rediscovered spice. In: Dietary Supplements. C.T. Ho, J.E. Simon, F. Shahidi, Y. Shao (Eds.). American Chemical Society (ACS) Symposium Series 987. ACS, Washington D.C. pp 100-113.

2008. H.R. Juliani, T. Kwon, A.R. Koroch, J. Asante-Dartey, D. Acquaye, J. E. Simon. Xylopia aethiopia (Annonaceae): Chemistry, Traditional uses and Functional Properties of An “African Pepper”.  In: Dietary Supplements. C.T. Ho, J.E. Simon, F. Shahidi, Y. Shao (Eds.). American Chemical Society (ACS) Symposium Series 987. ACS, Washington D.C. pp 114-128.

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