GB2508946A - Method of producing bean sprouts - Google Patents

Abstract

A method for producing bean sprouts comprises loading a batch of beans into a container, locating the container in a dark growing chamber, adding water to the container at a temperature of between 33°C and 36°C and soaking the beans for approximately 8 hours. The method further comprises removing a plug to open an outlet and thereby allowing the water to drain from the container. Subsequently the method comprises, for a period of between 5 and 6 days, periodically rinsing the beans with water, wherein the temperature of the water used to rinse the beans is gradually reduced from a maximum of approximately 25°C to a temperature of no less than 18°C, and periodically reducing the concentration of oxygen present in the growing chamber from a maximum of approximately 21% by volume to no less than 16% by volume.

Description

BEAN SPROUT PRODUCTION

The present invention relates to methods and apparatus for producing bean sprouts.

Bean sprouts are produced by germination of seeds such as mung beans or soybeans. The germination process typically takes around 7 to 10 days to produce a sprouted bean, and involves a sequence of operations in which the beans are soaked and/or rinsed with water at temperatures of between 21°C and 23°C in the absence of light.

Whilst it is possible to speed up the germination process simply by using higher temperatures, the resulting sprouts are undesirable, as they are relatively long, thin, lacking in crunch and have a shorter shelf-life. In addition, the resulting sprouts have relatively long roots, which make them difficult to process. Furthermore, the use of higher temperatures increases the risk of rot that occurs due to the growth of bacteria that may be present in the beans.

It is therefore desirable to provide methods and apparatus for growing bean sprouts that allow for a quicker and more efficient growing process than conventional methods and apparatus but is that do not compromise the quality or lifetime of the resulting bean sprouts.

Therefore, according to a first aspect there is provided a method of producing bean sprouts.

The method comprises loading a batch of beans into a container, the container being provided with an outlet that is temporarily sealed by a plug and a filter plate located above the outlet that supports the beans, locating the container in a dark growing chamber, adding water to the container at a temperature of between 33°C and 36°C and soaking the beans for approximately 8 hours. The method further comprises removing the plug to open the outlet and thereby allowing the water to drain from the container. Subsequently, for a period of between 5 and 6 days, periodically rinsing the beans with water, wherein the temperature of the water used to rinse the beans is gradually reduced from a maximum of approximately 25°C to a temperature of no less than 18°C, and periodically reducing the concentration of oxygen present in the growing chamber from a maximum of approximately 21% by volume to no less than 16% by volume. Typically, the water added to the container for soaking the beans is at a temperature of approximately 35°C.

The container may be approximately 1.4 metres in height, 1.3 metres in length and 0.9 metres in width, and the outlet may be approximately 6.3 centimetres in diameter.

The filter plate may be approximately 25cm above the bottom of the container. The filter plate may be provided with a grid of through-holes, wherein each of the through-holes is between 0.8 and 1 centimetre in length and 0.3 centimetres in width. The through-holes may make-up at least 30% of the total surface area of the filter plate.

S The concentration of oxygen present in the growing chamber can be reduced by extracting air from the growing chamber. The method may further comprise, following the soaking of the beans, periodically introducing ethylene into the growing chamber. The volume of ethylene introduced into the growing chamber may be proportional to a volume of air that has been extracted from the growing chamber.

According to a second aspect there is provided a method of producing bean sprouts substantially as described and illustrated in the accompanying drawings.

According to a third aspect there is provided a bean sprout produced according to the method of the first or second aspects.

According to a fourth aspect there is provided an apparatus for producing bean sprouts substantially as described and illustrated in the accompanying drawings.

The present invention will now be more particularly described by way of example only with reference to the accompanying drawings, in which: Figure la illustrates schematically a sideways cross-section through a bean sprout growing apparatus as described herein; Figure lb illustrates schematically a top-down view of a container of the apparatus of Figure 1 a; Figure lc illustrates schematically a top-down view of a filter plate of the apparatus of Figure la; Figure 2 is a flow diagram illustrating a process for growing bean sprouts that can be implemented using the apparatus described herein; Figure 3a illustrates schematically a sideways cross-section through the apparatus of Figure la during an initial stage of the process describe herein; and Figure 3b illustrates schematically a sideways cross-section through the apparatus of Figure la during a further stage of the process describe herein.

The rate of growth of a bean sprout during a conventional germination process is exponential.

In other words, the rate of growth gradually increases throughout the process. One reason for this is the metabolic heat produced by the beans during the germination process leads to a continual increase in the local environmental temperature around the beans, and this increasing temperature increases the rate of growth of the sprout.

The present inventors have determined that by maintaining an approximately linear rate of growth throughout the germination process, it is possible to accelerate the germination process so as to produce bean sprouts within 5 to 6 days, without compromising the quality or lifetime of the resulting bean sprouts. In particular, the present inventors have determined that an approximately linear rate of growth can be maintained by proactively optimising the environmental conditions throughout the duration of the germination process, and have developed a germination apparatus that allows for optimisation of the environmental conditions within the apparatus.

Referring now to Figures 1 a, lb and 1 c, there is shown an embodiment of an apparatus for use in growing bean sprouts that allows for optimisation of the local environmental conditions within the apparatus. The apparatus thereby provides for a quicker and more efficient growing process than conventional methods and apparatus, without compromising the quality or lifetime of the resulting bean sprouts.

Figure la illustrates schematically a sideways cross-section through the apparatus 10. In the embodiment of Figure 1 the apparatus 10 comprises a container/tank 11 mounted on wheels/castors 12 and a plate/tray 13 that sits within the interior recess/hollow of the container 11. Figure lb illustrates schematically a top-down view of the container 11 with the plate 13 removed, whilst Figure lc illustrates schematically a top-down view of the plate 13.

The container 11 has four side walls and a base/bottom ha such that the general shape of container 11 is that of an open box/cube. The approximate dimensions of the container 11 are: height (H) 1.4m, length (L) 1.3m, width (W) 0.9m. The container 11 is provided with a shelf/lip 11 b that projects from the inner surface of the side walls, and a number of projections 11 c that extend upwards from the base ha of the container ii. The top surface of the lip lib and the top surface of the projections 1 ic are coplanar, and provide a platform upon which the plate 13 is supported within the container 11. Preferably! the shelf ii b and the projections 11 c have an approximate height of 25cm.

The container 11 is further provided with an outlet/drain lid that extends through one of the side walls of the container 11 just above the base (and below the plane in which the plate 13 is supported). The outlet lid is approximately 6.3cm (2.5 inches) in diameter and can be sealed using a corresponding plug/bung ile. The outlet lid is sized so as to optimise both the rate at which water drains out of the container and the rate of gas exchange between the container ii and a room/chamber in which the container 11 is located during the germination process.

The plate 13 is provided with a grid/matrix of through-holes/slots 13a (i.e. long, narrow apertures) that are each around 0.8 to 1cm long and 0.3cm wide. The slots 13a are narrow enough to ensure that beans will not fall through and are long enough to ensure that the beans will not block the holes. The distribution of the slots 13a over the filter plate 13 should be optimised so as to ensure that the plate has sufficient strength and rigidity to support the beans that are loaded onto it and to maximise the rate at which water drains through the filter plate 13.

In this regard, depending upon the material from which the filter plate 13 is manufactured, at least 30% of the total surface area of the plate should be provided with slots 13.Figure 2 is a flow diagram illustrating a process for growing bean sprouts that can be implemented using the apparatus described above. The stages performed are as follows: Si. Loading: At the start of the process, the plate 13 is located inside the container ii where it is supported by the top surfaces of the lip llb and the projections llc, and the plug lie is fitted within the outlet lid to seal the outlet. A batch of un-germinated beans 14 are then loaded/placed onto the top surface of the plate 13 within the container ii, and the container ii is placed in a dark (i.e. absent of light) growing room/chamber. For example, approximately 50kg of seeds will typically be loaded into the container.

S2. Soaking: A volume of water 15 at a temperature of between 33°C and 36°C is then added to the container 11 (e.g. using a shower/sprinkler system 16), as illustrated in Figure 3a. The volume of water is sufficient to cover the beans and to thereby allow the beans to soak. . This water is left in the container ii for approximately 8 hours in order to bring the beans out of dormancy and initiate the germination of the beans. Chlorine may also be added to the soaking water in order to disinfect the bean.

53. Draining: The plug lie is then removed from the outlet lid so that the soaking water is allowed to flow out/drain from the container ii.

54a: Rinsing: Throughout the remainder of the germination process that follows the soaking stage, the beans are periodically (i.e. regularly or intermittently) rinsed with water, at an interval of between 2 to 4 hours. In this regard, the interval used will typically be 3 hours; however, this may be varied to accommodate variations in different batches of seeds. For example, if the container is initially loaded with 50kg of seeds, approximately 250 litres of water would be used during each rinsing step.

The temperature of the water used to rinse the beans is gradually reduced from a maximum of approximately 25°C to a temperature of no less than 18°C. In other words, from the start of the rinsing stage, the temperature of the water added to the container 11 is progressively reduced throughout the remainder of the germination process. By way of example, starting an initial value of 25°C, the temperature of water used during each rinsing step can be reduced by 1°C on a daily basis. The temperature sequence of the rinsing water used during each day would then be: 25°C, 24°C, 23°C, 22°C, 21°C.

The sequence/profile of temperatures used to rinse the beans throughout the germination process is determined by the growth rate required.

As the plug lie has been removed from the outlet lid, such that the outlet lid is open, the rinsing water is allowed to flow through the beans, filter through the holes 13a in the plate 13 into the bottom of the container 11, and drain out through the outlet lid under the force of gravity.

S4b: Oxygen Concentration Control: In addition, throughout the remainder of the germination process following the soaking stage, the concentration of oxygen within the growing chamber is varied intermittently by venting/extracting air from the growing chamber (e.g. using an extraction system 17), as illustrated in Figure 3b. The volume of oxygen within the growing chamber is thereby reduced from a maximum of approximately 21% by volume to no less than 16% by volume. In other words, from the start of the extraction stage, the volume of oxygen in the growing chamber is progressively reduced throughout the remainder of the germination process. By way of example, during the first and second days of the germination process, the concentration of oxygen in the growing chamber can be maintained at approximately 20% by volume (compared with approximately 21% in air), which can then be reduced by around 0.5% on each subsequent day such that the final concentration of oxygen is approximately 18% by volume.

S4c: Ethylene Addition: Preferably, throughout the remainder of the germination process following the soaking stage, the growth of the sprouts is stimulated by introducing ethylene into the growing chamber (e.g. via a pipe or duct 18), as illustrated in Figure 3b.

Ethylene (C2H4) is a gaseous plant hormone and functions as a natural growth regulator that promotes the ripening of fruit and stimulates shoot growth.

Ethylene is introduced into the growing chamber (e.g. via a pipe/duct 18) intermittently, and the amount of ethylene introduced is proportional to the volume of air extracted as part of the oxygen concentration control. The volume/concentration of ethylene in the growing chamber is therefore approximately constant throughout the process.

S5: The germination process is considered complete when the cotyledons of the beans have shrunk. In this regard, when the germination process is complete! the weight of the bean sprouts within the container will be approximately ten times that of the initial seeds.

For example, 50kg of seed will typically result in 500kg of germinated bean sprouts.

S The shape, size and distribution of the slots 1 3a in the filtering plate 13 and the outlet lid allow for optimised water and gas exchange between the beans and the growing room throughout the process. In this regard, oxygen (02) promotes growth of the beans, whilst carbon dioxide (GO2) that is given off by the beans as a waste product of respiration inhibits growth. However, the greater the oxygen concentration during the germination process, the greater the length of the root on the resulting bean sprout. The size of the outlet lid relative to the container ii therefore optimises the rate of gas exchange between the container 11 and the growing chamber, so as to minimise the root length without detrimentally impacting upon the germination process. In particular, oxygen present in the growing chamber can enter the container ii through the outlet lid and pass up through the beans in order to promote growth, whilst carbon dioxide is flushed down and out through the outlet 11 d together with the rinsing water.

In addition, by gradually reducing both the temperature of the water that is used to rinse the beans and the concentration of oxygen present in the growing chamber, the process described above proactively maintains an approximately linear rate of growth for the bean sprouts.

Furthermore, the gradual reduction of the temperature throughout the process allows for the use of higher initials temperature of around 25°C, thereby accelerating the germination process so as to produce bean sprouts within 5 to 6 days.

By reducing the time taken to produce bean sprouts from between 7 and 10 days to between 5 and 6 days, the methods described above also reduces the amount of water used, as the total number of rinsing steps will be fewer. In addition, the method described above also makes use of a longer interval between rinses than prior art methods (i.e. lower frequency rinsing)! which further reduces the number of rinsing steps required, and therefore enhances the reduction in water usage. In this regard, the method describe above typically requires around 35 litres of water for every kilogram of bean sprouts produced, whilst conventional method use between 50 and 85 litres of water for every kilogram of bean sprouts.

Furthermore, the methods and apparatus described above produce a bean sprout that is approximately 20% shorter and fatter than a bean sprout grown using conventional methods, and that has roots that are approximately 20% shorter than those of a bean sprout grown using conventional methods. Moreover, individual batches of bean sprouts grown according to the methods and apparatus described above have significantly less variance than batches of bean sprouts grown using conventional methods. In this regard, when grown using conventional methods, the longest bean sprouts within a batch can typically be up to 100% longer than the shortest bean sprouts. For this reason, it is not uncommon for a commercial producer of bean sprouts to throw away the top layer of sprouts because they are too long. In contrast, the longest bean sprouts within a batch grown according to the methods and apparatus described above will typically be no more than 50% longer than the shortest bean sprouts in the batch.

It will be appreciated that individual items described above may be used on their own or in combination with other items shown in the drawings or described in the description and that items mentioned in the same passage as each other or the same drawing as each other need not be used in combination with each other. In addition, the expression means" may be replaced by actuator or system or device as may be desirable. In addition, any reference to "comprising" or "consisting" is not intended to be limiting in any way whatsoever and the reader should interpret the description and claims accordingly.

Furthermore, although the invention has been described in terms of preferred embodiments as set forth above, it should be understood that these embodiments are illustrative only. Those skilled in the art will be able to make modifications and alternatives in view of the disclosure which are contemplated as falling within the scope of the appended claims.

Claims (12)

1. CLAIMS1. A method of producing bean sprouts comprising: loading a batch of beans into a container, the container being provided with an outlet that is temporarily sealed by a plug and a filter plate located above the outlet that supports the beans; locating the container in a dark growing chamber; adding water to the container at a temperature of between 33°C and 36°C and soaking the beans for approximately 8 hours; removing the plug to open the outlet and thereby allowing the water to drain from the container; and subsequently, for a period of between 5 and 6 days, periodically rinsing the beans with water, wherein the temperature of the water used to rinse the beans is gradually reduced from a maximum of approximately 25°C to a temperature of no less than 18°C, and periodically reducing the concentration of oxygen present in the growing chamber from a maximum of approximately 21% by volume to no less than 16% by volume.
2. 2. A method as claimed in claim 1, wherein the water added to the container for soaking the beans is at a temperature of approximately 35°C.
3. 3. A method as claimed in any of claims 1 and 2, wherein the container is approximately 1.4 metres in height, 1.3 metres in length and 0.9 metres in width, and the outlet is approximately 6.3 centimetres in diameter.
4. 4. A method as claimed in claim 3, wherein the filter plate is approximately 25cm above the bottom of the container.
5. 5. A method as claimed in any preceding claim, wherein the filter plate is provided with a grid of through-holes, wherein each of the through-holes is between 0.8 and 1 centimetre in length and 0.3 centimetres in width.
6. 6. A method as claimed in any preceding claim, wherein at least 30% of the total surface area of the plate is provided with through-holes.
7. 7. A method as claimed in any preceding claim, wherein the concentration of oxygen present in the growing chamber is reduced by extracting air from the growing chamber.
8. 8. A method as claimed in any preceding claim, and further comprising: following the soaking of the beans, periodically introducing ethylene into the growing chamber.
9. 9. A method as claimed in claim 8 when dependent on claim 7, wherein the volume of ethylene introduced into the growing chamber is proportional to a volume of air that has been extracted from the growing chamber.
10. 10. A method of producing bean sprouts substantially as described and illustrated in the accompanying drawings.
11. 11. A bean sprout produced according to the method of any of the preceding claims.
12. 12. An apparatus for producing bean sprouts substantially as described and illustrated in the accompanying drawings.Amendments to the claims have been filed as follows.CLAIMS1. A method of producing bean sprouts comprising: loading a batch of beans into a container, the container being provided with an outlet that is temporarily sealed by a plug and a filter plate located above the outlet that supports the beans; locating the container in a dark growing chamber; adding water to the container at a temperature of between 33°C and 36°C and soaking the beans for 8 hours; removing the plug to open the outlet and thereby allowing the water to drain from the container; and subsequently, for a period of between 5 and 6 days, periodically rinsing the beans with water, wherein the temperature of the water used to rinse the beans is gradually reduced from a maximum of 25°C to a temperature of no less than 18°C, and periodically reducing the concentration of oxygen present in the growing chamber from a maximum of 21% by volume to no less than 16% by volume.2. A method as claimed in claim 1, wherein the water added to the container for soaking the beans is at a temperature of 35°C.3. A method as claimed in any of claims 1 and 2, wherein the container is 1.4 metres in height, 1.3 metres in length and 0.9 metres in width, and the outlet is 6.3 centimetres in diameter.4. A method as claimed in claim 3, wherein the filter plate is 25cm above the bottom of the container.5. A method as claimed in any preceding claim, wherein the filter plate is provided with a grid of through-holes, wherein each of the through-holes is between 0.8 and 1 centimetre in length and 0.3 centimetres in width.6. A method as claimed in any preceding claim, wherein at least 30% of the total surface area of the plate is provided with through-holes.7. A method as claimed in any preceding claim, wherein the concentration of oxygen present in the growing chamber is reduced by extracting air from the growing chamber.8. A method as claimed in any preceding claim, and further comprising: following the soaking of the beans, periodically introducing ethylene into the growing chamber.9. A method as claimed in claim 8 when dependent on claim 7, wherein the volume of ethylene introduced into the growing chamber is proportional to a volume of air that has been extracted from the growing chamber.10. A method of producing bean sprouts substantially as described and illustrated in the accompanying drawings. C?) (4