For blood vessel sprouting, see Angiogenesis#Sprouting angiogenesis.
Sprouting is the practice of germinating seeds to be eaten either raw or cooked. They are a convenient way to have fresh vegetables for salads, or otherwise, in any season and can be germinated at home or produced industrially. Sprouts are believed to be highly nutritious and rich in enzymes which promote good health. They are a prominent ingredient of the raw food diet and common in Eastern Asian cuisine. Sprouting is also applied on a large scale to barley as a part of the malting process. A downside to consuming raw sprouts is that the process of germinating seeds is conducive to bacterial growth, resulting in dozens of outbreaks of lethal infection with Salmonella and E. coli over the past few decades.
Seeds suitable for sprouting
Many seeds can be sprouted, but some sprouts cannot be eaten raw. The most commonly sprouted seeds include:
- Pulses (pea family):
- Vegetables and herbs:
- broccoli, carrot, spinach, cabbage, celery, fennel, onion, parsley, radish, turnip, leek, watercress, mustard, rocket (arugula), lemon grass, lettuce, clover, mizuna, milk thistle, tatsoi.
Although whole oats can be sprouted, oat groats sold in stores, which are dehulled and require steaming or roasting to prevent rancidity, will not sprout. Whole oats may have an indigestible hull which makes them unfit for human consumption.
All the sprouts of the solanaceae (tomato, potato, paprika, aubergine or eggplant) and rhubarb cannot be eaten as sprouts, either cooked or raw, as they can be poisonous. Some sprouts can be cooked to remove the toxin, while others cannot.
With all seeds, care should be taken that they are intended for sprouting or human consumption rather than sowing. Seeds intended for sowing may be treated with chemical dressings. Several countries, such as New Zealand, also require that some varieties of edible seed be heat-treated, thus making them impossible to sprout. Quinoa in its natural state is very easy to sprout but when pre-cleaned of its saponin coating (becoming whiter), loses its power to germinate.
The germination process
The germination process that lasts few days, can be done at home manually, as semi-automated process or industrially when done on a large scale for commercial use.
The seeds are normally first soaked and depending on the type of seed this process can take anything from 20 minutes up to 12 hours. Sometime before the soaking seeds are rinsed to remove soil and dirt and mucilaginous substances produced by some seeds when they come in contact with water. The soaking increases the water content in the seeds and bring them out of quiescence.
It follows draining and then rinsing seeds at regular intervals until they germinate, or sprout.
To sprout seeds, the seeds are moistened, then left at room temperature (between 13 and 21 °C or 55 and 70 °F) in a sprouting vessel. Many different types of vessels can be used. One type is a simple glass jar with a piece of cloth secured over its rim. ‘Tiered’ clear plastic sprouters are commercially available, allowing a number of "crops" to be grown simultaneously. By staggering sowings, a constant supply of young sprouts can be ensured. Any vessel used for sprouting must allow water to drain from it, because sprouts that sit in water will rot quickly. The seeds will swell and begin germinating within a day or two.
Sprouts are rinsed between twice a day and three or four times a day accordingly with climate and type of seed, to prevent them from souring and providing them with moisture. Each seed has its own ideal sprouting time. Depending on which seed is used, after three to five days they will have grown to 5 to 8 centimetres (2–3 in) in length and will be suitable for consumption. If left longer they will begin to develop leaves, and are then known as baby greens. A popular baby green is sunflower after 7–10 days. The growth process of any sprout can be slowed or halted by refrigerating until needed.
Common causes for sprouts to become inedible:
- Seeds are allowed to dry out
- Seeds are left in standing water
- Temperature is high or too low
- Insufficient rinsing
- Dirty equipment
- Insufficient air flow
- Contaminated source of water
- Poor rate of germination of seed
Mung beans can be sprouted either in light or dark conditions. Those sprouted in the dark will be crisper in texture and whiter, as in the case of commercially available Chinese Bean Sprouts, but these have less nutritional content than those grown in partial sunlight. Growing in full sunlight is not recommended, because it can cause the beans to overheat or dry out. Subjecting the sprouts to pressure, for example, by placing a weight on top of them in their sprouting container, will result in larger, crunchier sprouts similar to those sold in Polish grocery stores.
A very effective way to sprout beans like lentils or azuki is in colanders. Soak the beans in water for about 8 hours then place in the colander. Wash twice a day. The sprouted beans can be eaten raw or cooked.
Sprouting is also applied on a large scale to barley as a part of the malting process. Malted barley is an important ingredient in beer and is used in huge quantities. Most malted barley is distributed among wide retail sellers in North American regions.
Many varieties of nuts, such as almonds and peanuts, can also be started in their growth cycle by soaking and sprouting, although because the sprouts are generally still very small when eaten, they are usually called "soaks".
Sprouts are said to be rich in digestible energy, bioavailable vitamins, minerals, amino acids, proteins, and phytochemicals, as these are necessary for a germinating plant to grow. These nutrients are essential for human health. To clarify, the nutritional changes upon germination & sprouting have been summarized below. Chavan and Kadam (1989) concluded that - “The desirable nutritional changes that occur during sprouting are mainly due to the breakdown of complex compounds into a more simple form, transformation into essential constituents and breakdown of nutritionally undesirable constituents.”
“The metabolic activity of resting seeds increases as soon as they are hydrated during soaking. Complex biochemical changes occur during hydration and subsequent sprouting. The reserve chemical constituents, such as protein, starch and lipids, are broken down by enzymes into simple compounds that are used to make new compounds.”
“Sprouting grains causes increased activities of hydrolytic enzymes, improvements in the contents of total proteins, fat, certain essential amino acids, total sugars, B-group vitamins, and a decrease in dry matter, starch and anti-nutrients. The increased contents of protein, fat, fibre and total ash are only apparent and attributable to the disappearance of starch. However, improvements in amino acid composition, B-group vitamins, sugars, protein and starch digestibilities, and decrease in phytates and protease inhibitors are the metabolic effects of the sprouting process.”
Increases in Protein Quality Chavan and Kadam (1989) stated - “Very complex qualitative changes are reported to occur during soaking and sprouting of seeds. The conversion of storage proteins of cereal grains into albumins and globulins during sprouting may improve the quality of cereal proteins. Many studies have shown an increase in the content of the amino acid Lysine with sprouting.”
“An increase in proteolytic activity during sprouting is desirable for nutritional improvement of cereals because it leads to hydrolysis of prolamins and the liberated amino acids such as glutamic and proline are converted to limiting amino acids such as lysine.”
Increases in Crude Fibre content Cuddeford (1989), based on data obtained by Peer and Leeson (1985), stated - “In sprouted barley, crude fibre, a major constituent of cell walls, increases both in percentage and real terms, with the synthesis of structural carbohydrates, such as cellulose and hemicellulose”. Chung et al. (1989) found that the fibre content increased from 3.75% in unsprouted barley seed to 6% in 5-day sprouts.”
Crude Protein and Crude Fibre changes in Barley Sprouted over a 7-day period
Crude Protein Crude Fibre (% of DM) (% of DM)
Original seed 12.7% 5.4% Day 1 12.7% 5.6% Day 2 13.0% 5.9% Day 3 13.6% 5.8% Day 4 13.4% 7.4% Day 5 13.9% 9.7% Day 6 14.0% 10.8% Day 7 15.5% 14.1%
Source: Cuddeford (1989), based on data obtained by Peer and Leeson (1985).
Increases in Essential Fatty Acids
An increase in lipase activity has been reported in barley by MacLeod and White (1962) , as cited by Chavan and Kadam (1989) . Increased lipolytic activity during germination and sprouting causes hydrolysis of triacylglycerols to glycerol and constituent fatty acids.
Increases in Vitamin content According to Chavan and Kadam (1989) , most reports agree that sprouting treatment of cereal grains generally improves their vitamin value, especially the B-group vitamins. Certain vitamins such as α-tocopherol (Vitamin-E) and β-carotene (Vitamin-A precursor) are produced during the growth process (Cuddeford, 1989) .
According to Shipard (2005) - “Sprouts provide a good supply of Vitamins A, E & C plus B complex. Like enzymes, vitamins serve as bioactive catalysts to assist in the digestion and metabolism of feeds and the release of energy. They are also essential for the healing and repair of cells. However, vitamins are very perishable, and in general, the fresher the feeds eaten, the higher the vitamin content. The vitamin content of some seeds can increase by up to 20 times their original value within several days of sprouting. Mung Bean sprouts have B vitamin increases, compared to the dry seeds, of - B1 up 285%, B2 up 515%, B3 up 256%. Even soaking seeds overnight in water yields greatly increased amounts of B vitamins, as well as Vitamin C. Compared with mature plants, sprouts can yield vitamin contents 30 times higher.”
Chelation of Minerals Shipard (2005) claims that - “When seeds are sprouted, minerals chelate or merge with protein, in a way that increases their function.”
It is important to note that while these changes may sound impressive, the comparisons are of dormant, non-sprouted seed to sprouted seed rather than comparisons of sprouts to normal sized vegetables.
Commercially grown sprouts are associated with multiple outbreaks of harmful bacteria like salmonella or the toxic forms of Escherichia coli. Such infections, which are so frequent in the United States that investigators call them "sproutbreaks", may be a result of contaminated seeds or of unhygienic production with high microbial counts. Sprout seeds can become contaminated in the fields where they are grown, and sanitizing steps may be unable to kill bacteria hidden in damaged seeds. A single surviving bacterium in a kilogram of seed can be enough to contaminate a whole batch of sprouts, according to the FDA.
To minimize the impact of the incidents and maintain public health, both the U.S. Food and Drug Administration (FDA) and Health Canada issued industry guidance on the safe manufacturing of edible sprouts and public education on their safe consumption. There are also publications for hobby farmers on safely growing and consuming sprouts at home. The recommendations include development and implementation of good agricultural practices and good manufacturing practices in the production and handling of seeds and sprouts, seed disinfection treatments, and microbial testing before the product enters the food supply.
In June 2011, contaminated bean sprouts in Germany were identified as the source of the 2011 E. coli O104:H4 outbreak. In addition to Germany, where 3,792 cases and 42 deaths had been reported as of 22 June, a handful of cases have been reported in several countries including Switzerland, Poland, the Netherlands, Sweden, Denmark, the UK, Canada and the USA. Essentially all affected people had been in Germany shortly before becoming ill.
Some legumes, including sprouts, can contain toxins or antinutritional factors, which can be reduced by soaking, sprouting and cooking (e.g., stir frying). Joy Larkcom advises that to be on the safe side “one shouldn’t eat large quantities of raw legume sprouts on a regular basis, no more than about 550g (20oz) daily”.
Phytic acid, an antinutritional factor, occurs primarily in the seed coats and germ tissue of plant seeds. It forms insoluble or nearly insoluble compounds with many metal ions, including those of calcium, iron, magnesium and zinc, reducing their dietary availability. Diets high in phytic acid content and poor in these minerals produce mineral deficiency in experimental animals (Gontzea and Sutzescu, 1958, as cited in Chavan and Kadam, 1989). The latter authors state that the sprouting of cereals has been reported to decrease levels of phytic acid. Similarly, Shipard (2005) states that enzymes of germination and sprouting can eliminate detrimental substances such as phytic acid.
- Whole grains
- ^ Donald G. Barceloux MD. "Potatoes, Tomatoes, and Solanine Toxicity (Solanum tuberosum L., Solanum lycopersicum L.)". http://www.sciencedirect.com/science/article/pii/S0011502909000340. Retrieved 7 August 2011. Paid subscription required to access article.
- ^ "The Vegetarian Society - Information Sheet - pulses". Vegetarian Society. http://www.vegsoc.org/info/pulses.html. Retrieved 2009-11-16.
- ^ "Plant-based nutrition". Spring 2002. http://www.plantbased.org/PLANT_BASED_NUTRITION_2002-02.doc. Retrieved 2007-11-14.
- ^ a b c d e Neuman, William (10 June 2011). "The Poster Plant of Health Food Can Pack Disease Risks". New York Times. http://www.nytimes.com/2011/06/11/business/11sprouts.html?ref=global-home&gwh=2954AC55431292D8F5723F90E3DFD672. Retrieved 11 June 2011.
- ^ Breuer, Thomas et al.. "A Multistate Outbreak of Escherichia coli O157:H7 Infections Linked to Alfalfa Sprouts Grown from Contaminated Seeds". http://www.cdc.gov/ncidod/eid/vol7no6/breuer.htm. Retrieved 19 November 2007.
- ^ Gabriel, Alonzo A. et al.; Berja, M; Estrada, A; Lopez, M; Nery, J; Villaflor, E (2007). "Microbiology of retail mung bean sprouts vended in public markets of National Capital Region, Philippines". Food Control 18 (10): 1307–1313. doi:10.1016/j.foodcont.2006.09.004.
- ^ Food and Drug Administration (May 17, 2005). "Transcript of Proceedings of Public Meeting on Sprout Safety". http://www.fda.gov/Food/FoodSafety/Product-SpecificInformation/FruitsVegetablesJuices/ucm078701.htm. Retrieved 19 November 2007.
- ^ Health Canada. "Sprouted Beans and Seeds". http://www.hc-sc.gc.ca/fn-an/securit/ill-intox/info/sprouts-pousses_e.html. Retrieved 19 November 2007.
- ^ Harrison, H. C.. "Growing Edible Sprouts at Home" (PDF). http://learningstore.uwex.edu/pdf/A3385.PDF. Retrieved 23 November 2007.
- ^ Suslow, Trevor V.; Linda J. Harris. "Growing Seed Sprouts at Home" (PDF). http://postharvest.ucdavis.edu/datastorefiles/234-412.pdf. Retrieved 23 November 2007.
- ^ a b c d e f g h "Outbreak of Shiga toxin-producing E. coli in Germany (22 June 2011, 11:00)". ECDC. 22 June 2011. http://ecdc.europa.eu/en/activities/sciadvice/Lists/ECDC%20Reviews/ECDC_DispForm.aspx?List=512ff74f%2D77d4%2D4ad8%2Db6d6%2Dbf0f23083f30&ID=1120&RootFolder=%2Fen%2Factivities%2Fsciadvice%2FLists%2FECDC%20Reviews. Retrieved 22 June 2011.
- ^ "E. coli cucumber scare: Russia announces import ban". BBC News Online. 30 May 2011. Archived from the original on 30 May 2011. http://www.webcitation.org/5z4jXeT1m. Retrieved 30 May 2011.
- ^ "E. Two in U.S. infected in German E. coli outbreak". MSNBC Online. 31 May 2011. http://www.msnbc.msn.com/id/43227702/ns/health-infectious_diseases/. Retrieved 2 June 2011.
- ^ Larkcom, Joy ‘Salads For Small Gardens’, p.98 Hamlyn 1995 ISBN 0-600-58509-3
- The Raw Truth by Jeremy A Safron, (Celestial Arts, Toronto, 2003) ISBN 1-58761-172-4 (pbk.)
- "The Complete Guide to Successful Sprouting for Parrots" by Leslie Moran, (Critter Connection, US, 2007) ISBN 978-1-4196-8479-1 (110 pgs, pbk.)
- Title: Hydroponic grass. Source: In Practice. (Cuddeford, D., 1989). (Relates to Animal Nutrition)
- Title: NUTRITIONAL IMPROVEMENT OF CEREALS BY FERMENTATION. Source: CRITICAL REVIEWS IN FOOD SCIENCE AND NUTRITION (CHAVAN, JK; KADAM, SS, 1989)
- Title: How can I grow and use Sprouts as living food. (Shipard 2008) ISBN 9780975825204
- Sprout Recipes Sprout recipes for every lifestyle and palate
- Sprout links
- Sprout People
- Ch. 4 Microbiological safety of sprouted seed production - in Code of Practice for Food Safety in the Fresh Produce Supply Chain in Ireland
- Annex I - Proposed Draft Annex for Sprout Production - in Appendix II - Proposed Draft Code of Hygienic Practice for the Primary Production, Harvesting and Packing of Fresh Fruits and Vegetables (at Step 5 of the Procedure) of Report of the Thirty Third Session of the Codex Committee on Food Hygiene
- Horticulture and gardening
- Raw foodism
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