Technical field

The present invention relates to an apparatus and method for producing food pearls, also known as “popping boba”.

Background art

“Popping boba” pearls appear as small pearls consisting of a thin gel-like film that surrounds and contains juice inside, and when crushed they burst releasing the contained juice.

“Popping boba” pearls are known to be used as a flavoring in drinks, for example tea (“bubble tea”), milkshakes, slushies, or as decorations for cakes.

Apparatuses for the production of “popping boba” are known in the industry. In particular, there are known automated production lines with a series of devices for each production step. In fact, the production line includes devices for preparing and mixing foodstuff, tanks containing reagent solutions, devices with moving heads for releasing doses of foodstuff into the tanks for forming food pearls, roller systems for transporting the pearls and tanks for washing them.

However, current industrial “popping boba” production lines are expensive and require the use of machinery with complex handling mechanisms that do not always guarantee the geometric regularity of the produced pearls or prevent the agglomeration of several pearls.

In the prior art, compact apparatus for the production of “popping boba” according to both an “inverse spherification” mode and an “direct spherification” mode are known.

Patent publications CN 108967808 A and KR 20180095297 A disclose an apparatus for “reverse spherification” comprising a reservoir for holding a mixture of foodstuff and calcium lactate, a collecting tank for holding a sodium alginate solution, a feed pump connected to the reservoir to pump the mixture of foodstuff and calcium lactate from the reservoir to the collecting tank, and a drip nozzle connected to the reservoir to drip the mixture into the collecting tank to obtain pearls of product. Patent publication CN 108967808 A provides for the formed pearls to be extracted by means of a conveyor.

Patent publication EP 3560584 Al discloses an apparatus for “reverse spherification” comprising a first tank for containing a mixture of foodstuff and calcium salts, a second tank for containing a sodium alginate solution, and a third collecting tank. A pump and a gravity valve are configured to respectively convey the contents of the first and second tanks to a drip nozzle and then into the third tank to form pearls of product. The formed pearls are extracted by means of a worm screw.

Patent application FR 2645439 Al discloses an apparatus for “direct spherification” comprising a collecting tank for containing a salt solution, a reservoir for containing an alginate solution, a pump for drawing the alginate solution from the reservoir and supplying it to a drip nozzle arranged to drip the alginate solution into the tank, resulting in pearls. A transport device, partially immersed in the tank, is arranged to transport the pearls out of the tank.

Patent publication KR 20200025230 A discloses an apparatus for “reverse spherification” comprising a closed tank for containing an alginate solution and is arranged to be kept under pressure by means of a supply tube and an air suction tube. The tank has also a feed tube arranged on the top wall of the tank for the solution containing a calcium salt and a siphon tube arranged on the base of the tank for the extraction of the pearls produced.

Summary of the invention

A general object of the present invention is to provide an apparatus and a method for producing food pearls more simply, effectively and economically.

Another object of the present invention is to prevent agglomeration of the pearls during production. The above and other objects and advantages, which will be better understood herein after, are achieved according to an aspect of the present invention by apparatus having the features set forth in independent claim 1. Preferred embodiments of the invention and a method for making pearls are set forth in the dependent claims.

In summary, according to a first aspect, the present invention proposes an apparatus for producing foodstuff pearls comprising at least one reservoir arranged to contain a foodstuff solution, a collecting tank arranged to contain a reagent liquid bath, a vertical tube having a first height, a lower end open and arranged to be immersed in the reagent liquid bath and a closed top end having a drip nozzle in fluid communication with the reservoir, and a vacuum pump communicating with the top end of the vertical tube. The vacuum pump is arranged to generate a vacuum in the proximal end of the vertical tube to draw the foodstuff solution from the reservoir to the drip nozzle and to also draw a column of reagent liquid into the vertical tube to a second predetermined height, vertically distanced from the drip nozzle and having a free surface.

A second aspect of the present invention provides a method for producing foodstuff pearls using the apparatus defined in the appended claims.

Brief description of the drawings

The features and advantages of the invention will be apparent from the following detailed description of a few embodiments thereof, made with reference to the accompanying drawing, which is a schematic view of the apparatus for the production of foodstuff pearls.

Detailed description

As shown in the drawing, an apparatus 10 for the production of food pearls known as “popping boba” comprises a reservoir 12 arranged to contain a foodstuff solution 14 of a substantially liquid consistency, a collecting tank 16 arranged to contain a reagent liquid bath 18, a vertical tube 20 and a vacuum pump 28. Throughout this description and in the claims, terms and expressions indicating positions and orientations such as "top", "bottom", "high" and "low" shall be construed as referring to a condition of normal use of the apparatus 10 for producing pearls.

The vertical tube 20 has an open lower end 22 arranged to be immersed in the reagent liquid bath 18 contained in the collecting tank 16. The vertical tube 20 has also a closed top end 24, closed for example by means of a cap, which is equipped with a drip nozzle 26 in fluid communication with the reservoir 12.

In an alternative embodiment (not illustrated), the apparatus 10 may also comprise a plurality of vertical tubes, each of which has the open lower end 22 arranged to be immersed in the reagent liquid bath 18 and the closed top end 24 provided with a respective drip nozzle 26 in fluid communication with the reservoir 12.

In one embodiment, when several vertical tubes are present, there may also be a plurality of reservoirs arranged to contain one or more foodstuff solutions 14. For example, the reservoirs may contain foodstuff solutions with different flavors for the simultaneous production of pearls flavored with different flavors.

Alternative embodiments to that illustrated in the figure may provide, for the or each vertical tube 20, several drip nozzles 26, suitably spaced horizontally to avoid collisions and agglomeration of droplets. Each drip nozzle 26 is connected to a reservoir 12 by means of a respective supply conduit 34.

According to a particular embodiment, there may be two or more reservoir 12, arranged to contain identical or different foodstuff solutions, and to be connected to two or more drip nozzles 26 of the same vertical tube 20 by means of respective supply conduits 34.

Preferably, the vertical tube 20 may have a circular cross-section, and have a height, referred to herein as the "first" height hl, varying from a few centimeters up to several meters, depending on production requirements. The diameter, or transverse dimension of the vertical tube 20, may vary from a few millimeters to more than 1 meter. It will be clear to those skilled in the art that the vertical tube 20 may also have a different cross-sectional shape, i.e. it may have a polygonal crosssection.

The apparatus 10 further comprises a vacuum pump 28 communicating with the top end 24 of the vertical tube 20; when operated, the vacuum pump 28 generates a vacuum d in the top end 24 of the vertical tube 20.

By way of indication, the vacuum pump's suction capacity may be in the range of about -0.1 kPa to about -100 kPa, with suitable flow rates to compensate for the drip flow, which may vary according to production requirements, from 0.01 liters/minute to 220 liters/minute, depending on the diameter of the tube and the number of drip nozzles. For example, with a vertical tube 20 having a diameter of 34 mm, an 8 mm drip nozzle can produce a flow rate of 0.05 liters/minute or 3 liter s/h.

The suction or depression d generated by the vacuum pump 28 allows the foodstuff solution 14 to be drawn from the reservoir 12 towards the drip nozzle 26 in a dosed manner. In addition, the depression d at the top end allows a column 30 of reagent liquid 18 to be drawn from the collecting tank 16 within the vertical tube 20 to a second predetermined height h2, vertically spaced from the drip nozzle 26, and forming a free surface 32 of reagent liquid 18.

In particular, the first height hl of the vertical tube 20 is greater than the second height h2 of the column 30 of reagent liquid 18 drawn inside the vertical tube 20 by the vacuum d generated by the vacuum pump 28.

The collecting tank 16 may be open on top, while the reservoir 12 may be open on top or closed.

The reservoir 12, arranged to contain the foodstuff solution 14, may be fluidically connected to the one or more drip nozzles of each vertical tube 20 by means of a respective supply conduit 34. The supply conduit 34 may be, for example, a flexible hose.

In order to allow a dosed extraction of material from the reservoir 12 under the action of the vacuum pump 28, the supply conduit 34 may vary in diameter between a minimum of 1 mm up to 100 mm, depending on the desired droplet diameter.

The reservoir 12 may be positioned relative to the drip nozzle 26 at an adjustable height by means of a height adjustment device 13. The height adjustment of the reservoir 12 allows to set the rate of flow of foodstuff solution 14 from the reservoir 12 towards the drip nozzle 26.

The reservoir 12 may be arranged at a lower height than the drip nozzle 26. By appropriately adjusting the difference in height between the reservoir 12 and the drip nozzle 26, i.e. by reducing the difference in height, it is advantageously possible to limit the vacuum d which must be exerted by the vacuum pump 28 in order to draw the foodstuff solution 14 towards the drip nozzle 26. By increasing the height difference between the reservoir 12 and the drip nozzle 26, i.e. by lowering the reservoir 12, it is advantageously possible to reduce or stop the flow of foodstuff solution 14 towards the drip nozzle 26.

In an embodiment, the reservoir 12 may be pressurized to assist in sending the foodstuff solution 14 towards the drip nozzle 26. In such an embodiment the vacuum pump 28 may be advantageously arranged to exert a lower vacuum d to draw the foodstuff solution 14 from the reservoir 12 towards the drip nozzle 26.

Alternative embodiments may provide for the reservoir 12 to be placed at essentially the same level as the drip nozzle 26.

Further embodiments may provide for the reservoir 12 to be placed at a higher level than the drip nozzle 26, thereby promoting by gravity the flow of the foodstuff solution 14 through the supply conduit 34. The supply conduit 34 is to be dimensioned in such a way that the foodstuff solution 14 flows out of the drip nozzle 26 in the form of single drops, and not as a continuous trickle. According to some embodiments, droplet formation 36 may take place in a manner known as “direct spherification”, whereby the foodstuff solution 14 also contains a thickener, while the reagent liquid 18 includes a calcium salt in solution.

In an embodiment, the foodstuff solution 14 contained in the reservoir 12 may comprise a liquid, for example a fruit juice or extract, and sodium alginate to thicken the liquid, resulting in a more viscous, for example gel-like, solution. In particular, in such an embodiment, sodium alginate may be added to the foodstuff solution 14 in a percentage, for example between 1% and 5%, to obtain a desired viscosity of the solution and preferably in the range between 20 and 200 centipoise (cP), with a density preferably between 1.13 and 1.18. In such an embodiment, i.e. when the foodstuff solution 14 contained in the reservoir 12 comprises sodium alginate, the reagent liquid 18 may comprise a calcium salt chosen from calcium lactate, calcium chloride and calcium gluconate, in percentages between about 1% and about 3%.

According to other embodiments, the formation of the droplets 36 may take place in a manner known as “reverse spherification”, whereby the foodstuff solution 14 also contains a calcium salt, while the reagent liquid 18 comprises a thickener, for example sodium alginate. In a particular embodiment, the foodstuff solution 14 placeable in the reservoir 12 may comprise a liquid to which an appropriate amount of calcium salt is added, chosen from calcium lactate, calcium chloride and calcium gluconate. In particular, in such an embodiment, calcium salt may be added to the foodstuff solution 14 in a percentage between about 1% and about 4%. In such an embodiment, i.e., wherein the foodstuff solution 14 comprises a calcium salt, the reagent liquid 18 may comprise sodium alginate in a percentage between about 1% and about 5%.

The apparatus 10 described herein above may be used for the production of food pearls. Essentially, the vacuum pump 28 is actuated to generate a vacuum d at the top end of the vertical tube 20 and draw in a dosed manner the foodstuff solution 14 contained in the reservoir 12 and also draw the column 30 of reagent liquid 18 within the vertical tube 20 to the second predetermined height h2. The column 30 of reagent liquid 18 within the vertical tube 20 forms the free surface 32, as described above. By appropriately adjusting the vacuum d caused by the vacuum pump 28, it is possible to adjust the height of the free surface 32 so that it is spaced vertically and inferiorly with respect to the drip nozzle 26. That is, that the free surface 32 of the column 30 is lower than the drip nozzle 26 arranged at the top of the vertical tube 20.

The vertical distance between the free surface of the column 30 of reagent liquid 18 and the drip nozzle 26 may be in the range from 3 cm to 30 cm, and in any case sufficient to allow the drop leaving the drip nozzle 26 to take a spherical shape.

The drawn foodstuff solution 14 is dispensed from the drip nozzle 26 in the form of single drops 36.

The flow rate of foodstuff solution delivered by the drip nozzle 26 can be determined based on the vacuum d exerted by the vacuum pump 28, the cross-sectional area of the supply conduit 34 and the viscosity of the foodstuff solution. These parameters may be varied and chosen such that the flow rate of foodstuff solution 14 arriving at the drip nozzle 26 allows the foodstuff solution 14 to be delivered discontinuously, i.e. in the form of single droplets 36.

Once dispensed from the drip nozzle 26, the single drops 36 of foodstuff solution 14 fall by a predetermined free fall height h3 so that they take a substantially spherical shape while they fall.

The predetermined free fall height h3 corresponds to the vertical offset between the first height hl of the vertical tube 20 and the second height h2 of the column 30 of reagent liquid 18, i.e. the vertical offset between the drip nozzle 26 and the free surface 32 of the column 30 of reagent liquid 18.

When the single drops or pearls 36 come in contact with the reagent liquid 18, they precipitate therein along the vertical tube 20 for a predetermined precipitation time t such that the single drops 36 in spherical shape each form a superficial film 38 before coming in contact with other drops or pearls 36. The superficial film, which progressively thickens and hardens, prevents the pearls from agglomerating if they come in contact with each other.

By appropriately sizing the second height h2 of the column 30 of the reagent liquid 18, it is possible to determine the predetermined precipitation time t of the single drops 36 of foodstuff solution 14 in the reagent liquid 18 so that the superficial film 38 is formed.

The predetermined precipitation time t for the formation of the superficial film 38 of the droplets 36 may also be defined according to the concentration of calcium alginate contained in the foodstuff solution 14. For example, for 1% calcium alginate concentrations, a solidification time of about 90 s can be expected, for 2% calcium alginate concentrations, a solidification time of about 60 s can be expected.

The pearls 36 containing foodstuff solution 14 and confined by a superficial film 38, for example a thin substantially solid or gelatinous film, may vary in diameter, typically between 1 mm and 20 mm, and preferably about 8-9 mm in diameter. The pearls 36 can accumulate and settle in the collecting tank, from where they can then be picked up.

While specific embodiments of the invention have been described, it must be understood that this disclosure is provided purely for illustrative purposes and that the invention is not to be limited in any way by it. Various modifications will become apparent to those skilled in the art in the light of the above examples. The scope of the invention is limited only by the appended claims.