Chapters 8.26: Difference between revisions

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(Created page with "<div> <div class="title"><h3>8.26-Sweet Potato Value Addition</h3><br><h3 class="ch-owner">Alex Roberts, University of Guelph, Canada </h3></div> <div class="hero-img-2"> 300px <p>Suggested citation for this chapter.</p> <p>Roberts,A. (2022) Sweet Potato Value Addition,In Farmpedia, The Encyclopedia for Small Scale Farmers. Editor, M.N. Raizada, University of Guelph, Canada. http://www.farmpedia.org</p> <h3 class="title-bg">Introduction</h3>...")
 
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  <div class="title"><h3>8.26-Sweet Potato Value Addition</h3><br><h3 class="ch-owner">Alex Roberts, University of Guelph, Canada </h3></div>
  <div class="title"><h3>8.26-Using Maize (Corn) Silk as a Source of Profits and Improved Human Health</h3><br><h3 class="ch-owner">Lianna van der Zalm , University of Guelph, Canada </h3></div>
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<p>Suggested citation for this chapter.</p>
<p>Suggested citation for this chapter.</p>
<p>Roberts,A. (2022) Sweet Potato Value Addition,In Farmpedia, The Encyclopedia for Small Scale Farmers. Editor, M.N. Raizada, University of Guelph, Canada. http://www.farmpedia.org</p>
<p>van der Zalm,L. (2022) Using Maize (Corn) Silk as a Source of Profits and Improved Human Health,In Farmpedia, The Encyclopedia for Small Scale Farmers. Editor, M.N. Raizada, University of Guelph, Canada. http://www.farmpedia.org</p>
       <h3 class="title-bg">Introduction</h3>
       <h3 class="title-bg">Background of Corn and Corn Silk</h3>
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           <P>Sweet potato is a widely grown root crop ( Business Diary, 2017); its large, starchy, sweet-tasting, tuberous roots compose a nutritious vegetable. The young leaves and shoots are sometimes eaten as greens (ActionAid, 2015). Over 95% of the global sweet potato crop is produced in developing countries. More than 130 million tons are produced per year, with China producing about 80% of it (ActionAid, 2015). Sweet potato is rich in carbohydrates, phosphorus, and an excellent source of Vitamins A, B and C (Business Diary, 2017). It is known to lower cholesterol with curative effects for constipation and stomach stress. Value addition from sweet potatoes has become an increasing topic in the food world today as it has endless uses and all of the plant can be used as food for humans or feed for livestock (Business Diary, 2017). Sweet potatoes are widely becoming a novel root vegetable for functional foods, as it is nutritious and widely accessible (Sweet Potato Knowledge Portal, 2018). Functional foods are described as foods that contribute to an overall healthy body (Sweet Potato Knowledge Portal, 2018).</p>
           <P>In 94 developing countries across the world, 4.5 billion people get at least 30% of their calories from corn making it a staple for many (International Maize and Wheat Improvement Centre, 2016). Corn is wind-pollinated: the pollen is caught by corn silks at the tip of each ear and they travel down corn silks where they reach and fertilize eggs to give rise to kernels (IPBO, 2017). Corn silks are usually discarded, but they represent a simple opportunity for smallholder maize farmers to obtain extra income from a product they are already producing. </p>
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       <h3 class="title-bg">Wrapping</h3>
       <h3 class="title-bg">Health Benefits of Corn Silk</h3>
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<p>The simplest value addition ideas would be to wrap sweet potatoes in newspaper in order to limit their exposure to light. Light can accelerate the autooxidation of fats and oils. This is imperative to increase shelf life, as well it can be more attractive to buyers; this can be advertised as offering a longer shelf life then other competitors (FoodSafetySite, 2012). Not wrapping each in their own individual package can lead to mold and harmful bacteria that can age sweet potatoes (FoodSafetySite, 2012). And wrapping each in an individual package would prevent pathogen cross-contamination (Lerner, B. Rosie, 2018). This process can be done extremely fast by hand and would result in a prolonged shelf life. Wrapping may be more expensive and time consuming, however, buying used newspaper or books can be inexpensive. Recycling can also lead to a cleaner environment; this can benefit smallholder farmers who sell what they produce (Knott, S., 2018). However, there is insufficient data on the price difference for wrapped compared to unwrapped sweet potatoes.</p>
<p>Corn silk has been used for thousands of years as a traditional cure for a multitude of health issues by the Chinese and Native Americans (Hasanudin et al., 2012). Today, it is used in many parts of the world as a traditional medicine such as in Turkey, the United States and France (Hasanudin et al., 2012). There are many proposed health benefits such as a variety of nutrients and natural cures including urinary infections, cystitis, edema, prostate disorders, antioxidant, hyperglycemia, depression and fatigue (Hasanudin et al., 2012).</p>
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<p>Mature corn silk contains a variety of nutrients, minerals and antioxidants. The chart below shows the approximate compositions of these components.</p>
<p><i>Table 1: Nutrient and mineral composition on mature corn silk (Rahman & Rosli, 2014).</i></p>
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<p>For urinary infections, cystitis, edema and prostate disorders, corn silk has been used as an anti-inflammatory (Steenkamp, 2003). When the bladder and urethral walls are irritated it makes it more difficult to urinate (Steenkamp, 2003). When corn silk is consumed, it relieves the lining of the urinary system reducing irritation (Steenkamp, 2003).</p>
<p>When oxidation occurs in the body it can cause damage to cells which can eventually lead to diseases such as cancers, diabetes, atherosclerosis and aging (Hasanudin et al., 2012). Corn silk has been studied as a potential antioxidant to prevent the occurrence of oxidation reducing the probability of the above diseases or reducing their advancement (Hasanudin et al., 2012).</p> 
<p>Hyperglycemia is a condition characterized with diabetes as it indicates an elevated level of blood glucose when the body is not utilizing insulin properly (American Diabetes Association, 2018). A test done on mice showed that corn silk reduced hyperglycemia by increasing insulin levels and recovering injured cells (Guo et al., 2009).</p> 
<p>Corn silk has also been tested in its effectiveness as an anti-depressant and anti-fatigue supplement. The anti-depressant is based on the high levels of phenol and flavonoids and showed similar results as an anti-depressant drug (Mahmoudi & Ehteshami, 2010). For anti-fatigue, a test was done on mice showing that there was an inhibitory factor for blood lactic acid increasing hepatic glycogen concentration increasing the drive of the mice (Hu et al., 2010).</p>
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      <h3 class="title-bg">Making Corn Silk Powder</h3>
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<p>For corn silk products, the silk can be either dried or left as is but drying the silk will extend the shelf life. To begin, the silk should be washed to make sure no pests are present (Alterman, 2013). Once washed, pat dry with a towel and then place them in a drying rack. The drying area needs to be between 25°C-30°C for optimal conditions with minimal humidity and with no sunlight so that the nutrients do not get lost (Alterman, 2013). Link 1 in the Helpful Hints section leads to an option for a drying rack which is black, so the material will absorb more sunlight than the silk if it cannot be placed in the dark. After drying is complete (silk no longer has moisture), the silk can be chopped finely for easier use. This can be done with a knife or the device found in link 2 in Helpful Hints. After chopping, the silk should be put in an air tight container until use (Ness, 2018).</p>
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      <h3 class="title-bg">Value Addition as a Tea</h3>
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<p>Corn silk tea is the way Chinese people have been utilizing corn silk’s benefits for thousands of years (TCM World Foundation, 2015). The tea can be prepared either in tea bags to sell, or directly in a steeper to sell directly to the consumer. If tea bags are being made, place 2 teaspoons of dried corn silk into a bag such as the ones found in link 3 in Helpful Hints (Gale Encyclopedia of Alternative Medicine, 2018). To make the tea, the tea bag should be placed in boiling water and steeped for 15-20 minutes (Gale Encyclopedia of Alternative Medicine,2018). To be effective, the mixture should be drunk 3 times a day (Gale Encyclopedia of Alternative Medicine, 2018). If the fresh corn silk is being used, 1 tablespoon should be added to 1 cup of boiling water and left to steep for 20 minutes (Radhakrishnan, 2017). The tea should then be strained and sold for drinking (Radhakrishnan, 2017). Honey, agave or any natural sweetener can be added to add sweetness (Radhakrishnan, 2017). Other herbs can be added to the teas to increase their value such as dandelion leaves, nettle leaves and uva ursi for a bladder helper tea (Sun and Moon Dispensary, 2017).</p>
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      <h3 class="title-bg">Value Addition as a Tincture</h3>
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<p>A tincture is a higher concentration of an extract of an herb or plant (Wong, 2018). The herb is soaked in alcohol to extract the nutrients for a few weeks where it is then strained and bottled (Wong, 2018). To make a corn silk tincture, a mason jar or something similar should be filled ¼ full with chopped fresh corn silk and the rest filled with a high proof alcohol such as vodka (Radhakrishnan, 2017). After 4-6 weeks in a cool dark place the mixture can be strained (Radhakrishnan, 2017). ¼ to ½ a teaspoon can be taken 3 times a day (Radhakrishnan, 2017).</p>
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       <h3 class="title-bg">Labeling</h3>
       <h3 class="title-bg">Value Addition as a Powder for Soups/Stew Type Meals</h3>
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<p>Value addition could be achieved simply by noting the nutrient benefits of processed sweet potato on packaging. For example, baking the potatoes instead of frying or boiling allows for more nutrients to be kept (Dincer, Cuneyt, et al., 2011). Baking a potato only requires cutting then placing onto a sheet in an oven. Labeling can improve sale value/rate, while adding a quick recipe (like baked fries) could add further value. Also, including the nutritional value of sweet potatoes can be beneficial (Sustain, 2007). A study from Miller & Cassady (2015) supports the claim that including nutritious information helps increase the sale of products by increasing the rate of sales, since ‘knowledge-is-power’. This would be best sold to tourists or at markets.</p>  
<p>Since corn silk has a light taste, if added to meals the benefits would be present without a flavor change (Ness, 2018). Dried corn silk can be used directly in meals and sold as a spice (Ness, 2018). Even fresh corn silk can be added to meals after being chopped if it is used within a couple of days after harvesting.</p>
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       <h3 class="title-bg">Flour</h3>
       <h3 class="title-bg">Cost Analysis</h3>
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<p>Sweet potato root can be used to produce a variety of flours, which would be subsequently used to make breads, pastries and noodles (CIP, 2018). The process of producing flour from sweet potato root is described in full below. The following diagram shows an overview of the process:</p> 
<p>The typical post harvest stages for corn involves husking the corn before storing it so instead of throwing the husks out, the corn silk can simply be separated from the husks in this step adding only seconds to the process (Shepherd, 1999). To rinse the corn silk, the cost of labour to get the water and containers for water need to be considered. To dry, the drying net in link 1 costs between $2-$15 depending on the location. The labour only needs to be considered for chopping unless the food chopper in link 2 is used which costs $4-$10. If tea bags are being created, then the cost of the bags range from $0.06-$0.11 per bag found in link 3. For the tincture, alcohol would most likely be sold at local markets. The only other unknown costs would be the type of packaging it would be sold in and the transport.</p>
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<p>The process requires a knife for cutting as well as a mill; mills can be priced as low as $60. A visual step by step process of making flour can be found at https://www.youtube.com/watch?v=GLEbnNnXqMA. This video is particularly useful because it describes the process in Kenya.  Sweet potato flour can be used to fortify other flours or to make bread itself. Fortifying other flours with sweet potato flour yielded the best results compared to other white breads made from wheat flour alone (Shan, Shan, et al., 2012). Hence the packaging could advertise that sweet potato fortified bread is healthier and contains more nutrients than traditional flours. Sweet potato flour is sold in Canada at Walmart (https://www.walmart.com/c/kp/potato-flour) for $17.86/Kg, thus a smallholder farmer can mill the roots and sell for a profit.</p>  
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       <h3 class="title-bg">Jam</h3>
       <h3 class="title-bg">Market Analysis</h3>
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<p>Sweet potato today can be used to make jams with only a blender (Business Diary, 2017), which the online retailer “Alibaba.com” sells for as little as $11. Blended sweet potato can also lead to value added products such as smoothies, drinks and catsup (Business Diary, 2017). This would help improve sales at road sides and markets.</p>
<p>As prices for produce and products change everyday and not a lot of information is available on where the best places to sell products is, connecting with an organization is probably the best opportunity for subsistence farmers. One organization called Farm Africa (a link can be found in link 4 in Helpful Hints) assists farmers in optimizing their growing and selling strategies (Farm Africa, 2018). They assist in increasing yields and quality and connect farmers together to sell in bulk and aid in marketing efficiency (Farm Africa, 2018). This organization knows local markets the best, making them a valuable connection to create. Some other potential selling areas would be at local markets, to local doctors or physicians to give as a treatment for the ailments discussed above or at grocery stores as a health product.  By using the health benefit information provided, packaging and marketing can be created to promote the use of the products for health concerns.</p>
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       <h3 class="title-bg">Sweet potato skins</h3>
       <h3 class="title-bg">Potential Issues</h3>
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<p>Farmers and consumers can use the whole tuber to maximize profits. As already noted, the root can be used to create flour for human consumption or can be sold as livestock feed ( CIP, 2018). The outer layer of the tuber, instead of being thrown away, contains many useful nutrients and protein which could be added to smoothies, jams, or drinks (Allrecipes, 2018). As stated before a blender can cost as low as $11 on Alibaba.com. Additionally, sweet potato skins can also be baked (Allrecipes, 2018).</p>
<p>For the tincture, it should be made apparent on the bottle that it does contain alcohol so pregnant women should not consume it. To reach toxicity levels of corn silk, one would have to consume more than 500 mg/kg of corn silk to body weight, which is a very high concentration (Ha et al., 2018). If the weather is poor, the corn silk can be dried in an oven or dehydrator as the moisture would be too high otherwise. One other issue could be that the corn silks may not form properly during drought or other types of stress (Nielsen, 2016).</p>
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       <h3 class="title-bg">Baked sweet potatoes</h3>
       <h3 class="title-bg">Helpful Hints</h3>
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<p>There is another popular value addition from sweet potatoes which serves as a healthy alternative to white fleshed potatoes. Sweet potatoes (baked, fried, boiled) are considered as a novel source for natural health promoting compounds (beta-carotene and anthocyanins) for the functional food market (Bovell et al., 2017). Boiling sweet potatoes result in a loss in carotenoids and other important vitamins and minerals (Gehse, Saskia, et al.), hence baking is an alternative. Baking is done in an oven, which can cost as little as $60 on Alibaba, or using rocks or clay. For the latter, a tutorial can be found at https://www.youtube.com/watch?v=z_OUaJVHnF0. Baking opens up new markets, such as to tourists or at local markets.</p>
<p>Link 1: Source for herb drying device
 
https://www.alibaba.com/product-detail/factory-price-hot-sale-black-herb_60778736385.html?spm=a2700.galleryofferlist.normalList.33.42184e57dqM5IU</p>
<p>In conclusion, there is an abundance of value addition ideas for sweet potato smallholder farmers, and there are still more to be discovered with research. Most of these products are realistic for smallholder farmers to implement.</p>
<p>Link 2: Source for food processor
https://www.alibaba.com/product-detail/2017-Creative-Kitchen-Pulling-Food-Chopper_60760225664.html?spm=a2700.galleryofferlist.normalList.294.62b73777Taidco</p>
<p>Link 3: Source for tea bags
https://www.alibaba.com/product-detail/Transparency-PLA-Biodegradable-Folding-Corn-Fiber_60787347001.html?spm=a2700.7724838.2017115.215.2bb17c60t1nap6</p>
<p>Link 4: Organization for crop and marketing aid
https://www.farmafrica.org/agriculture/agriculture-1</p>
<p>Link 5: YouTube video on how to make corn silk tea
https://www.youtube.com/watch?v=h5uiheCH01c</p>
<p>Link 6: Link for a variety of corn silk recipes
https://thenerdyfarmwife.com/uses-for-corn-silk/</p>
<p>Link 7: YouTube video on what corn silk can help health wise and how
https://www.youtube.com/watch?v=MV5kZUFbSEs</p>
<p>Link 8: How to make corn silk spice
https://delishably.com/spices-seasonings/Making-Homemade-Corn-Silk-Spice</p>
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       <h3 class="title-bg">References </h3>
       <h3 class="title-bg">References </h3>
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  <p>1. ActionAid. (2015). What is a small holder farmer? Retrieved from http://actionaid.org/australia/2015/06/smallholderfarmers101</p>
  <p>1. Alterman, T. (2013, February). Drying Herbs: Easier Than You Think - Real Food. Retrieved from https://www.motherearthnews.com/real-food/drying/drying-herbs-zm0z13fmzmat</p>
 
<p>2. American Diabetes Association (2018). Hyperglycemia (High Blood Glucose). Retrieved November 10, 2018, from http://www.diabetes.org/living-with-diabetes/treatment-and-care/blood-glucose-control/hyperglycemia.html</p>
<p>2. Bovell, B. Adelia C. (2007) Sweet Potato: A Review of Its Past, Present, and Future Role in Human Nutrition. Advances in Food and Nutrition Research, 7, 1–59, doi:10.1016/s1043-4526(06)52001-7.</p>
<p>3. Farm Africa (2018). Agriculture. Farmafrica.org. Retrieved from: https://www.farmafrica.org/agriculture/agriculture-1</p>
 
<p>4. Gale Encyclopedia of Alternative Medicine (2018). Cornsilk.  Encyclopedia.com.  Retrieved from https://www.encyclopedia.com/medicine/encyclopedias-almanacs-transcripts-and-maps/cornsilk</p>
<p>3. Describe the different ways that food spoils. (2012). Retrieved from http://www.foodsafetysite.com/educators/competencies/general/microbiology/mic6.html</p>
<p>5. Guo, J., Liu, T., Han, L., & Liu, Y. (2009). The effects of corn silk on glycaemic metabolism. Nutrition & Metabolism,6(1), 47. Retrieved from https://nutritionandmetabolism.biomedcentral.com/articles/10.1186/1743-7075-6-47.</p>
 
<p>6. Ha, A. W., Kang, H. J., Kim, S. L., Kim, M. H., & Kim, W. K. (2018). Acute and Subacute Toxicity Evaluation of Corn Silk Extract. Preventive Nutrition and Food Science,23(1), 70-76. Retrieved from https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5894788/.</p>
<p>4. Dincer, Cuneyt, et al. (2011) Effects of Baking and Boiling on the Nutritional and Antioxidant Properties of Sweet Potato [Ipomoea Batatas (L.) Lam.] Cultivars. Plant Foods for Human Nutrition, 66 (4), 341-347. doi:10.1007/s11130-011-0262-0.</p>
<p>7. Hasanudin, K., Hashim, P., & Mustafa, S. (2012). Corn Silk (Stigma Maydis) in Healthcare: A Phytochemical and Pharmacological Review. Molecules,17(8), 9697-9715. Retrieved from https://www.researchgate.net/publication/230665731_Corn_Silk_Stigma_Maydis_in_Healthcare_A_Phytochemical_and_Pharmacological_Review.</p>
 
<p>8. Hu, Q., Zhang, L., Li, Y., Ding, Y., & Li, F. (2010). Purification and anti-fatigue activity of flavonoids from corn silk. International Journal of Physical Sciences,5(4), 321-326. Retrieved from http://www.academicjournals.org/app/webroot/article/article1380726309_Hu et al.pdf</p>
<p>5. Gehse, Saskia, et al. (2018) Determination of the Effect of Boiling on the Bioavailability of Carotenoids in Vegetables Using Resonance Raman Spectroscopy. Laser Physics, 28(10), 105602. doi:10.1088/1555-6611/aad1b4.</p>
<p>9. International Maize and Wheat Improvement Centre (2016). Why Maize. CGIAR. Retrieved November 29, 2018, from https://maize.org/why-maize/</p>
 
<p>10. IPBO. (2017). Maize in Africa. International Plant Biotechnology Outreach. Retrieved from http://www.vib.be/en/about-vib/Documents/VIB_MaizeInAfrica_EN_2017.pdf</p>
<p>6. Knott, S. (2018, March 22). One of Africa's most promising cities has a trash problem. Retrieved from https://qz.com/africa/1229079/ghana-the-worlds-fastest-growing-economy-has-a-trash-problem/</p>
<p>11. Mahmoudi, M., & Ehteshami, S. (2010). P.2.d.002 Antidepressant activity of Iranian Corn Silk. European Neuropsychopharmacology,20(3), 392. Retrieved from https://www.sciencedirect.com/science/article/pii/S0924977X10705563.</p>
 
<p>12. Nielsen, B. (2016). Silk Development and Emergence in Corn. Purdue University. Retrieved from https://www.agry.purdue.edu/ext/corn/news/timeless/silks.html</p>
<p>7. Sweet Potato Knowledge Portal, www.sweetpotatoknowledge.org/files/presentation-12-low-cost-technologies-value-addition-orange-fleshed-sweetpotato-smallholder-farmers-western-kenya/.</p>  
<p>13. Ness, V. V. (2018, August 04). Making Homemade Corn Silk Spice. Delishably.com Retrieved from https://delishably.com/spices-seasonings/Making-Homemade-Corn-Silk-Spice</p>  
 
<p>14. Radhakrishnan, M. (2017, September 19). 10 Amazing Health Benefits of Corn Silk Tea. Stylecraze.com. Retrieved from https://www.stylecraze.com/articles/health-benefits-of-corn-silk-tea/#gref </p>
<p>8. Lerner, B. Rosie. “Time to Harvest Sweet Potatoes.” Purdue Extension - Purdue University, 21 Sept. 2018, http://extension.purdue.edu/article/30787.</p>
<p>15. Rahman, N. A., & Rosli, W. I. (2014). Nutritional compositions and antioxidative capacity of the silk obtained from immature and mature corn. Journal of King Saud University - Science,26(2), 119-127. Retrieved from https://www.sciencedirect.com/science/article/pii/S1018364713000773.</p>
 
<p>16. Shepherd, A.W. (1999) A guide to maize marketing for extension officers. Drying and storage. FAO, Rome. Retrieved from http://www.fao.org/docrep/005/x0530e/X0530E05.htm</p>
<p>9. Miller, L. M., & Cassady, D. L. (2015). The effects of nutrition knowledge on food label use. A review of the literature. Appetite, 92, 207-216. doi:10.1016/j.appet.2015.05.029</p>
<p>17. Steenkamp, V. (2003). Phytomedicines for the prostate. Fitoterapia,74(6), 545-552. Retrieved from https://www.sciencedirect.com/science/article/pii/S0367326X03001552?via=ihub.</p>
 
<p>18. (2017, August 15). Summer Harvest: Corn Silk.  Sunandmoondispensary.com. Retrieved from https://www.sunandmoondispensary.com/single-post/2017/08/15/Summer-Harvest-Corn-Silk</p>
<p>10. Obi, L. “15 Ways You Can Add Value to Potatoes for More Money.” Daily Nation, 30 Sept. 2016, www.nation.co.ke/business/seedsofgold/ways-you-can-add-value-to-potatoes-for-more-money/2301238-3400418-e4g4ul/index.html. (cite as Obi, 2016)</p>
<p>19. TCM World Foundation. (2015, August 24). Corn Silk Tea. TCMworld.org. Retrieved from https://www.tcmworld.org/recipes/corn-silk-tea/ </p>
 
<p>20. Wong, C. (2018, August 1). What you Need to Know About Herbal Tinctures. Verywellhealth.com. Retrieved from https://www.verywellhealth.com/herbal-tinctures-8939</p>
<p>11. Old Farmer's Almanac. (2018). Growing Sweet Potatoes. Retrieved November 29, 2018, from https://www.almanac.com/plant/sweet-potatoes</p>
 
<p>12. Shan, S., et al. (2012) Physicochemical Properties And Salted Noodle-Making Quality Of Purple Sweet Potato Flour And Wheat Flour Blends. Journal of Food Processing and Preservation, 37 (5) 709-716, doi:10.1111/j.1745-4549.2012.00686.x.</p>
 
<p>13. Sustain (2007). How can improved food labelling contribute to a healthy and sustainable food system? Retrieved from https://www.sustainweb.org/publications/how_can_improved_food_labelling_contribute/</p>
 
<p>14. “Sweet Potato Recipes.” Allrecipes, www.allrecipes.com/recipes/1094/fruits-and-vegetables/vegetables/sweet-potato/.</p>  
 
<p>15. “Sweet Potato Processing and Uses.” International Potato Center (CIP), cipotato.org/crops/sweetpotato/sweet-potato-processing-and-uses/.</p>
 
<p>16. “Value-Added Products from Sweet Potato.” Business Diary PH, Business Diary Ph, 8 Dec. 2017, businessdiary.com.ph/6427/value-added-products-sweet-potato/.</p>  
 
<p>17. Victoria Grain Mill - Corona Style. (n.d.). Retrieved from https://torontobrewing.ca/products/victoria-grain-mill-corona-style?variant=32012717379&utm_campaign=gs-2018-10-07&utm_source=google&utm_medium=smart_campaign&gclid=Cj0KCQiA8_PfBRC3ARIsAOzJ2uofbhQoD5PPMrJmemx2diMDGAHWGcxHijD9bGs-mKJ4GkNSNI9sHm8aAkNGEALw_wcB</p>

Revision as of 12:12, 6 July 2022

8.26-Using Maize (Corn) Silk as a Source of Profits and Improved Human Health


Lianna van der Zalm , University of Guelph, Canada

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Suggested citation for this chapter.

van der Zalm,L. (2022) Using Maize (Corn) Silk as a Source of Profits and Improved Human Health,In Farmpedia, The Encyclopedia for Small Scale Farmers. Editor, M.N. Raizada, University of Guelph, Canada. http://www.farmpedia.org

Background of Corn and Corn Silk

In 94 developing countries across the world, 4.5 billion people get at least 30% of their calories from corn making it a staple for many (International Maize and Wheat Improvement Centre, 2016). Corn is wind-pollinated: the pollen is caught by corn silks at the tip of each ear and they travel down corn silks where they reach and fertilize eggs to give rise to kernels (IPBO, 2017). Corn silks are usually discarded, but they represent a simple opportunity for smallholder maize farmers to obtain extra income from a product they are already producing.

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Health Benefits of Corn Silk

Corn silk has been used for thousands of years as a traditional cure for a multitude of health issues by the Chinese and Native Americans (Hasanudin et al., 2012). Today, it is used in many parts of the world as a traditional medicine such as in Turkey, the United States and France (Hasanudin et al., 2012). There are many proposed health benefits such as a variety of nutrients and natural cures including urinary infections, cystitis, edema, prostate disorders, antioxidant, hyperglycemia, depression and fatigue (Hasanudin et al., 2012).

Mature corn silk contains a variety of nutrients, minerals and antioxidants. The chart below shows the approximate compositions of these components.

Table 1: Nutrient and mineral composition on mature corn silk (Rahman & Rosli, 2014).

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For urinary infections, cystitis, edema and prostate disorders, corn silk has been used as an anti-inflammatory (Steenkamp, 2003). When the bladder and urethral walls are irritated it makes it more difficult to urinate (Steenkamp, 2003). When corn silk is consumed, it relieves the lining of the urinary system reducing irritation (Steenkamp, 2003).

When oxidation occurs in the body it can cause damage to cells which can eventually lead to diseases such as cancers, diabetes, atherosclerosis and aging (Hasanudin et al., 2012). Corn silk has been studied as a potential antioxidant to prevent the occurrence of oxidation reducing the probability of the above diseases or reducing their advancement (Hasanudin et al., 2012).

Hyperglycemia is a condition characterized with diabetes as it indicates an elevated level of blood glucose when the body is not utilizing insulin properly (American Diabetes Association, 2018). A test done on mice showed that corn silk reduced hyperglycemia by increasing insulin levels and recovering injured cells (Guo et al., 2009).

Corn silk has also been tested in its effectiveness as an anti-depressant and anti-fatigue supplement. The anti-depressant is based on the high levels of phenol and flavonoids and showed similar results as an anti-depressant drug (Mahmoudi & Ehteshami, 2010). For anti-fatigue, a test was done on mice showing that there was an inhibitory factor for blood lactic acid increasing hepatic glycogen concentration increasing the drive of the mice (Hu et al., 2010).

Making Corn Silk Powder

For corn silk products, the silk can be either dried or left as is but drying the silk will extend the shelf life. To begin, the silk should be washed to make sure no pests are present (Alterman, 2013). Once washed, pat dry with a towel and then place them in a drying rack. The drying area needs to be between 25°C-30°C for optimal conditions with minimal humidity and with no sunlight so that the nutrients do not get lost (Alterman, 2013). Link 1 in the Helpful Hints section leads to an option for a drying rack which is black, so the material will absorb more sunlight than the silk if it cannot be placed in the dark. After drying is complete (silk no longer has moisture), the silk can be chopped finely for easier use. This can be done with a knife or the device found in link 2 in Helpful Hints. After chopping, the silk should be put in an air tight container until use (Ness, 2018).

Value Addition as a Tea

Corn silk tea is the way Chinese people have been utilizing corn silk’s benefits for thousands of years (TCM World Foundation, 2015). The tea can be prepared either in tea bags to sell, or directly in a steeper to sell directly to the consumer. If tea bags are being made, place 2 teaspoons of dried corn silk into a bag such as the ones found in link 3 in Helpful Hints (Gale Encyclopedia of Alternative Medicine, 2018). To make the tea, the tea bag should be placed in boiling water and steeped for 15-20 minutes (Gale Encyclopedia of Alternative Medicine,2018). To be effective, the mixture should be drunk 3 times a day (Gale Encyclopedia of Alternative Medicine, 2018). If the fresh corn silk is being used, 1 tablespoon should be added to 1 cup of boiling water and left to steep for 20 minutes (Radhakrishnan, 2017). The tea should then be strained and sold for drinking (Radhakrishnan, 2017). Honey, agave or any natural sweetener can be added to add sweetness (Radhakrishnan, 2017). Other herbs can be added to the teas to increase their value such as dandelion leaves, nettle leaves and uva ursi for a bladder helper tea (Sun and Moon Dispensary, 2017).

Value Addition as a Tincture

A tincture is a higher concentration of an extract of an herb or plant (Wong, 2018). The herb is soaked in alcohol to extract the nutrients for a few weeks where it is then strained and bottled (Wong, 2018). To make a corn silk tincture, a mason jar or something similar should be filled ¼ full with chopped fresh corn silk and the rest filled with a high proof alcohol such as vodka (Radhakrishnan, 2017). After 4-6 weeks in a cool dark place the mixture can be strained (Radhakrishnan, 2017). ¼ to ½ a teaspoon can be taken 3 times a day (Radhakrishnan, 2017).

Value Addition as a Powder for Soups/Stew Type Meals

Since corn silk has a light taste, if added to meals the benefits would be present without a flavor change (Ness, 2018). Dried corn silk can be used directly in meals and sold as a spice (Ness, 2018). Even fresh corn silk can be added to meals after being chopped if it is used within a couple of days after harvesting.

Cost Analysis

The typical post harvest stages for corn involves husking the corn before storing it so instead of throwing the husks out, the corn silk can simply be separated from the husks in this step adding only seconds to the process (Shepherd, 1999). To rinse the corn silk, the cost of labour to get the water and containers for water need to be considered. To dry, the drying net in link 1 costs between $2-$15 depending on the location. The labour only needs to be considered for chopping unless the food chopper in link 2 is used which costs $4-$10. If tea bags are being created, then the cost of the bags range from $0.06-$0.11 per bag found in link 3. For the tincture, alcohol would most likely be sold at local markets. The only other unknown costs would be the type of packaging it would be sold in and the transport.

Market Analysis

As prices for produce and products change everyday and not a lot of information is available on where the best places to sell products is, connecting with an organization is probably the best opportunity for subsistence farmers. One organization called Farm Africa (a link can be found in link 4 in Helpful Hints) assists farmers in optimizing their growing and selling strategies (Farm Africa, 2018). They assist in increasing yields and quality and connect farmers together to sell in bulk and aid in marketing efficiency (Farm Africa, 2018). This organization knows local markets the best, making them a valuable connection to create. Some other potential selling areas would be at local markets, to local doctors or physicians to give as a treatment for the ailments discussed above or at grocery stores as a health product. By using the health benefit information provided, packaging and marketing can be created to promote the use of the products for health concerns.

Potential Issues

For the tincture, it should be made apparent on the bottle that it does contain alcohol so pregnant women should not consume it. To reach toxicity levels of corn silk, one would have to consume more than 500 mg/kg of corn silk to body weight, which is a very high concentration (Ha et al., 2018). If the weather is poor, the corn silk can be dried in an oven or dehydrator as the moisture would be too high otherwise. One other issue could be that the corn silks may not form properly during drought or other types of stress (Nielsen, 2016).

Helpful Hints

Link 1: Source for herb drying device https://www.alibaba.com/product-detail/factory-price-hot-sale-black-herb_60778736385.html?spm=a2700.galleryofferlist.normalList.33.42184e57dqM5IU

Link 2: Source for food processor https://www.alibaba.com/product-detail/2017-Creative-Kitchen-Pulling-Food-Chopper_60760225664.html?spm=a2700.galleryofferlist.normalList.294.62b73777Taidco

Link 3: Source for tea bags https://www.alibaba.com/product-detail/Transparency-PLA-Biodegradable-Folding-Corn-Fiber_60787347001.html?spm=a2700.7724838.2017115.215.2bb17c60t1nap6

Link 4: Organization for crop and marketing aid https://www.farmafrica.org/agriculture/agriculture-1

Link 5: YouTube video on how to make corn silk tea https://www.youtube.com/watch?v=h5uiheCH01c

Link 6: Link for a variety of corn silk recipes https://thenerdyfarmwife.com/uses-for-corn-silk/

Link 7: YouTube video on what corn silk can help health wise and how https://www.youtube.com/watch?v=MV5kZUFbSEs

Link 8: How to make corn silk spice https://delishably.com/spices-seasonings/Making-Homemade-Corn-Silk-Spice

References

1. Alterman, T. (2013, February). Drying Herbs: Easier Than You Think - Real Food. Retrieved from https://www.motherearthnews.com/real-food/drying/drying-herbs-zm0z13fmzmat

2. American Diabetes Association (2018). Hyperglycemia (High Blood Glucose). Retrieved November 10, 2018, from http://www.diabetes.org/living-with-diabetes/treatment-and-care/blood-glucose-control/hyperglycemia.html

3. Farm Africa (2018). Agriculture. Farmafrica.org. Retrieved from: https://www.farmafrica.org/agriculture/agriculture-1

4. Gale Encyclopedia of Alternative Medicine (2018). Cornsilk. Encyclopedia.com. Retrieved from https://www.encyclopedia.com/medicine/encyclopedias-almanacs-transcripts-and-maps/cornsilk

5. Guo, J., Liu, T., Han, L., & Liu, Y. (2009). The effects of corn silk on glycaemic metabolism. Nutrition & Metabolism,6(1), 47. Retrieved from https://nutritionandmetabolism.biomedcentral.com/articles/10.1186/1743-7075-6-47.

6. Ha, A. W., Kang, H. J., Kim, S. L., Kim, M. H., & Kim, W. K. (2018). Acute and Subacute Toxicity Evaluation of Corn Silk Extract. Preventive Nutrition and Food Science,23(1), 70-76. Retrieved from https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5894788/.

7. Hasanudin, K., Hashim, P., & Mustafa, S. (2012). Corn Silk (Stigma Maydis) in Healthcare: A Phytochemical and Pharmacological Review. Molecules,17(8), 9697-9715. Retrieved from https://www.researchgate.net/publication/230665731_Corn_Silk_Stigma_Maydis_in_Healthcare_A_Phytochemical_and_Pharmacological_Review.

8. Hu, Q., Zhang, L., Li, Y., Ding, Y., & Li, F. (2010). Purification and anti-fatigue activity of flavonoids from corn silk. International Journal of Physical Sciences,5(4), 321-326. Retrieved from http://www.academicjournals.org/app/webroot/article/article1380726309_Hu et al.pdf

9. International Maize and Wheat Improvement Centre (2016). Why Maize. CGIAR. Retrieved November 29, 2018, from https://maize.org/why-maize/

10. IPBO. (2017). Maize in Africa. International Plant Biotechnology Outreach. Retrieved from http://www.vib.be/en/about-vib/Documents/VIB_MaizeInAfrica_EN_2017.pdf

11. Mahmoudi, M., & Ehteshami, S. (2010). P.2.d.002 Antidepressant activity of Iranian Corn Silk. European Neuropsychopharmacology,20(3), 392. Retrieved from https://www.sciencedirect.com/science/article/pii/S0924977X10705563.

12. Nielsen, B. (2016). Silk Development and Emergence in Corn. Purdue University. Retrieved from https://www.agry.purdue.edu/ext/corn/news/timeless/silks.html

13. Ness, V. V. (2018, August 04). Making Homemade Corn Silk Spice. Delishably.com Retrieved from https://delishably.com/spices-seasonings/Making-Homemade-Corn-Silk-Spice

14. Radhakrishnan, M. (2017, September 19). 10 Amazing Health Benefits of Corn Silk Tea. Stylecraze.com. Retrieved from https://www.stylecraze.com/articles/health-benefits-of-corn-silk-tea/#gref

15. Rahman, N. A., & Rosli, W. I. (2014). Nutritional compositions and antioxidative capacity of the silk obtained from immature and mature corn. Journal of King Saud University - Science,26(2), 119-127. Retrieved from https://www.sciencedirect.com/science/article/pii/S1018364713000773.

16. Shepherd, A.W. (1999) A guide to maize marketing for extension officers. Drying and storage. FAO, Rome. Retrieved from http://www.fao.org/docrep/005/x0530e/X0530E05.htm

17. Steenkamp, V. (2003). Phytomedicines for the prostate. Fitoterapia,74(6), 545-552. Retrieved from https://www.sciencedirect.com/science/article/pii/S0367326X03001552?via=ihub.

18. (2017, August 15). Summer Harvest: Corn Silk. Sunandmoondispensary.com. Retrieved from https://www.sunandmoondispensary.com/single-post/2017/08/15/Summer-Harvest-Corn-Silk

19. TCM World Foundation. (2015, August 24). Corn Silk Tea. TCMworld.org. Retrieved from https://www.tcmworld.org/recipes/corn-silk-tea/

20. Wong, C. (2018, August 1). What you Need to Know About Herbal Tinctures. Verywellhealth.com. Retrieved from https://www.verywellhealth.com/herbal-tinctures-8939

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