Sprouting

For blood vessel sprouting, see Angiogenesis § Sprouting angiogenesis.

Mixed bean sprouts

Soybean sprouts

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.

Seeds that can be sprouted

Many seeds can be sprouted, but some sprouts, like kidney beans can not be eaten raw.

Here a list of the most common used:

• Pulses (pea family):

alfalfa, fenugreek, mung bean, lentil, pea, chickpea, soybean.

• Cereals:

oat, wheat, maize (corn), rice, barley, rye, kamut and then quinoa, amaranth and buckwheat (these last three are used as cereal even if botanically are they not.

• Oilseeds:

sesam, sunflower, almond, hazelnut, linseed.

• 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.

Safety by home-made sprouting

Some sprouts can be cooked to remove the toxin, while others cannot.

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!

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.

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.

Sprouting mung beans in a glass sprouter jar with a plastic sieve-lid

To sprout seeds, the seeds are moistened, then left at room temperature (between Template:C to F and Template:C to 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 two or three inches 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."

Nutritional information

Fresh Sprouts

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.

Health concerns

Risks and Antinutritional factors

FDA Health Warning

Public attention has been drawn to the safety of commercial sprouts. There have been outbreaks of Escherichia coli infection from alfalfa sprouts grown from contaminated seeds or unhygienic production with high microbial counts. 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.

SproutPeople.com[1] has called the July 9, 1999 press release by FDA Commissioner Jane Henney a, "muckraking piece of garbage," and their page condemned, "a media which does not examine the facts," as well as noting that, relative to other foodstuffs, the safety record of sprouts is excellent.

Commercially produced raw sprouts have been associated with foodborne illness. FDA and other public health officials are working with industry to identify and implement production practices that will assure that seed and sprouted seed are produced under safe conditions. While these efforts have improved food safety awareness within the industry and have led to a significantly better understanding of the microbial ecology of sprout-associated foodborne illness, not all industry segments have been reached and outbreaks continue to occur. Consequently, FDA released a guidance document, entitled "Guidance for Industry: Reducing Microbial Food Safety Hazards for Sprouted Seed" (the "sprout guidance"). The sprout guidance identifies a number of areas, from the farm to the sprout facility, where FDA believes immediate steps should be taken to reduce the risk of sprouts serving as a vehicle for foodborne illness and to ensure that sprouts are not adulterated under the Food, Drug, and Cosmetic Act (the act). Specific recommendations in the sprout guidance 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 product enters the food supply.

The agency will closely monitor the safety of commercially produced sprouts and the adoption of enhanced prevention practices as set out in the sprout guidance. FDA plans to send investigators to sprouting facilities to test water used to grow sprouts (i.e., spent irrigation water) and assess the adoption of preventive controls. Failure to adopt effective preventive controls can be considered insanitary conditions which may render food injurious to health. Food produced under such conditions is adulterated under the act (21 U.S.C. 342(a)(4)). FDA will consider enforcement actions against any party who does not have effective preventive controls in place, in particular, effective microbial testing.

Salmonella and Escherichia coli O157:H7 have been the major causes of contamination of commercially sold sprouts.

Seeds disinfected with contrast water resulted in better disinfection combined with better germination rate.

Some legumes can contain toxins or antinutritional factors, which can be reduced by soaking, sprouting and cooking (eg, 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”. However not all legume sprouts contain these antinutritional factors and many have beneficial properties so it is recommended that the advice of a qualified nutritionist is sought before making any decisions about what to include or eliminate from a diet.

Reduction of Anti-Nutritional Factors

Phytic acid 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.

Sprouting and the Living foods diet

Advocates of a raw food diet promote the use of sprouting as an effective way to increase vitamin content and digestibility. Some people believe sprouts to be the most nutrient-rich food on earth. Others feel this is a misinterpretation stemming from the way nutritional content is presented, with companies that sell seeds and sprouting products comparing the vitamin content of the seeds to that of the sprouts. When sprouts are compared to commonly eaten vegetables the overall vitamin content of sprouts has been shown to be substantially lower. This is not to say that eating sprouts is not nutritious or healthy, but rather, to show that there is no scientific evidence that sprouts are superior to other edible plants.

Many raw food dietitians recommend avoiding unsprouted grains, nuts and seeds as they the believe the raw unsprouted grains, nuts and seeds contain enzyme deactivators that harm the stomach.

Unlike most cooked foods, there are very few commercial avenues for purchasing sprouted foods. Most "raw foods bars" are raw but not sprouted (and therefore do not have active enzymes) because the bars would not keep as long on the shelf. The same is true of most nut and seed butters. The fact that sprouts have a limited shelf-life is seen as a nutritional asset, as it shows that the nutrients in sprouts are easily assimilated by the digestive system.

See also

• Aeroponics
• Hydroponics
• Whole grains

References

Bibliography

• 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

External links

• 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