A preparation method of smooth and boil-resistant rice noodles and a device for obtaining raw rice for preparing the rice noodles

Abstract

The present invention relates to the technical field of rice noodle processing, and in particular to a method for preparing smooth and resistant rice noodles and a device for obtaining raw rice for preparing the rice noodles. The method first uses a rice mill to mill indica rice to obtain indica rice, then cuts off the germ end of the indica rice to obtain the indica rice after the germ end is cut off, that is, the raw rice, and finally processes the raw rice by squeezing to obtain rice noodles; the present invention also provides a device for processing raw rice. The preparation method breaks the inertial thinking in the industry. Starting from the internal starch structure of indica rice, the quality of the prepared rice noodles can be improved by directly controlling the raw indica rice, and the rice noodles that are chewy, refreshing, and not soupy can be prepared. The rice noodles prepared by the preparation method are of high quality and good taste. By pre-treating the indica rice, they can be mass-produced without adjusting the existing rice noodle production line, which provides a new idea for improving the quality of rice noodles, the production and technical improvement of rice noodles, and is of great significance to the rice noodle industry.

Description

Technical Field

[0001] The present invention relates to the technical field of rice noodle processing, and specifically to a preparation method of smooth and boil-resistant rice noodles and a device for obtaining the raw rice for preparing the rice noodles. Background Art

[0002] Rice noodles are rice products made from rice as the main raw material through steps such as soaking, grinding (pulverizing), gelatinization, aging, and shaping. Indica rice is more suitable for making rice noodles because its amylose content is higher than that of japonica rice. When directly consumed, the taste of indica rice is coarser. And amylose molecules are prone to aging, with greater viscosity, higher water absorption rate, and can quickly form a gel after gelatinization (Du Lianqi et al., 2011; Yu Ping et al., 2011). Currently, most of the rice noodles on the market are made from indica rice.

[0003] However, the rice noodles made from indica rice have a soft and not refreshing taste, and the soup becomes cloudy during the cooking process and is prone to sticking to the pot. Li Xinhua et al. found in the study on the influence of production process conditions on the quality of rice noodles that adding 20 - 25% of corn starch to the rice flour raw material can improve the tensile strength and bonding strength of the rice noodles. In the prior art, in order to provide rice noodles with a Q - elastic texture that are more popular among consumers, additives such as monoglyceride, modified starch, konjac glucomannan, etc. need to be used in the raw rice flour to improve the adhesiveness of the rice noodles, but the improvement effect is still limited.

[0004] According to the local food safety standard of Yunnan Province DBS53 / 017 - 2023, rice noodles should use rice as the main raw material with a proportion of ≥60%, add one or more other grain cereals, edible starches, or other food raw materials with a proportion of ≤10%, and be made according to the corresponding process. According to this standard, some rice noodle products on the market that use additives or corn starch are not strictly suitable for sale as rice noodles.

[0005] Therefore, preparing rice noodles that meet the relevant standards, reduce the use of food additives, and are refreshing and boil - resistant is a technical problem that urgently needs to be solved to improve the quality of rice noodles and the market competitiveness of rice noodle foods, and thus it is urgent to solve. Summary of the Invention

[0006] In order to avoid and overcome the technical problems existing in the prior art, one of the purposes of the present invention is to provide a preparation method of smooth and boil - resistant rice noodles.

[0007] To achieve the above purpose, the present invention provides the following technical solutions:

[0008] A preparation method of smooth and boil - resistant rice noodles, comprising the following steps:

[0009] S1. Use a rice milling machine to mill indica paddy to obtain indica rice;

[0010] S2. Cut off the germ end of the indica rice, where the germ end accounts for 1 / 5 to 1 / 8 of the total length of the indica rice, and the indica rice after cutting off the germ end is called raw material rice;

[0011] S3. Process the raw material rice by means of flour extrusion to obtain the required rice noodles.

[0012] As a further scheme of the present invention: the steps of flour extrusion include: soaking the raw material rice, crushing and grinding, gelatinization, extrusion molding, freezing and drying.

[0013] As a further scheme of the present invention: the steps of gelatinization and extrusion molding are completed in a screw extruder. The raw material rice slurry obtained by grinding is put into the screw extruder. The raw material rice slurry is gelatinized by heating in the screw extruder and sprays out from the perforated panel arranged at the outlet end of the screw extruder to form rice noodles with a circular cross-section.

[0014] As a further scheme of the present invention: the water content in the raw material rice slurry obtained by grinding accounts for 70 - 80 wt%.

[0015] As a further scheme of the present invention: in the freezing process, first freeze in an environment of -18°C for 24 h, and then age in an environment of 4°C for 24 h.

[0016] In the present invention, rice milling and flour extrusion can use existing methods and devices. During the rice milling process, the moisture of the paddy can be conditioned first, and the indica paddy is hulled, separated from brown rice and milled by adjusting the clearance of the whitening chamber.

[0017] The longer the starch molecular chain is, after sufficient soaking and water absorption, and then through high-temperature cooking, the helical structure of the molecular chain is opened to become a linear molecule. After extrusion and spraying out through the perforated panel at the end, cooked rice noodles are formed. At this time, the cooked rice noodles are sent to a cold storage at -18°C for freezing for 24 hours. Water molecules form ice crystals and dehydrate with each other, and the starch molecular chains combine with each other. The longer the molecular chain is, the stronger the interaction is. Then the rice noodles frozen for 24 hours are sent to a cold storage at 4°C for accelerating aging for 24 hours, and then dried in the sun or in a drying room to obtain the finished product.

[0018] The second object of the present invention is to provide a kind of rice noodles prepared by using the above preparation method.

[0019] The third object of the present invention is to provide a device for obtaining raw material rice. This device is applied to the preparation method of a kind of smooth and chewable rice noodles. The device includes a feeding part for storing indica rice and quantitatively providing the indica rice to downstream processing equipment. At the discharge port of the feeding part, there is an orientation cutting part for receiving the indica rice and cutting off the germ end of the indica rice. At the outlet of the orientation cutting part, there is an aggregate part for receiving the indica rice after cutting off the germ end.

[0020] As a further solution of the present invention: The directional cutting part includes a receiving cylinder for receiving the falling indica rice, and only one indica rice with its length direction extending along the axial direction of the receiving cylinder can be accommodated in the cavity of a single receiving cylinder; a baffle plate that can block the lower port of the receiving cylinder is reciprocally slidably arranged along the radial direction of the receiving cylinder on the lower end surface of the receiving cylinder. A blanking hole is penetrated through the baffle plate, and the blanking hole can communicate with or be misaligned with the cavity of the receiving cylinder during the reciprocating sliding of the baffle plate to make the indica rice fall or stay in the receiving cylinder; an observation hole for observing the type of the end of the indica rice from the outside to the inside is opened on the cylinder wall of the receiving cylinder, and a depth camera for collecting an image of the end of the indica rice through the observation hole and identifying the type of the end of the indica rice is arranged outside the observation hole; an airbag that can inflate and squeeze the middle part of the indica rice to squeeze the indica rice against the cylinder wall of the receiving cylinder or deflate to eliminate the squeezed state of the indica rice according to the recognition result of the depth camera is also installed in the receiving cylinder; a cutting hole is also opened on the cylinder wall of the receiving cylinder, a cutting knife is fixedly installed on the baffle plate, and the cutting knife can enter the cutting hole and cut off the germ end of the indica rice when the baffle plate makes a sliding motion that misaligns the blanking hole with the cavity of the receiving cylinder.

[0021] As a further solution of the present invention: The directional cutting part includes a material receiving plate with a downwardly inclined plate surface. A material receiving hole is penetrated through the upper plate surface of the material receiving plate, and the axis of the material receiving hole is perpendicular to the plate surface of the material receiving plate; the receiving cylinder is fixedly installed on the lower plate surface of the material receiving plate, and the receiving cylinder and the material receiving hole are coaxially communicated with each other.

[0022] As a further solution of the present invention: A slide rail inclined in the same direction as the material receiving plate is installed on the support frame. A chute for the slide rail to be embedded and form a sliding fit is opened on the lower plate surface of the baffle plate; above the slide rail, a cutting telescopic rod with a telescopic direction parallel to the inclined direction of the slide rail is also installed on the support frame, and the baffle plate is fixedly installed at the telescopic end of the cutting telescopic rod.

[0023] As a further solution of the present invention: The observation hole and the cutting hole are both opened on the same side of the receiving cylinder, and the observation hole is above and the cutting hole is below; the depth camera is fixedly installed on the lower plate surface of the material receiving plate; the airbag is installed on the cylinder wall of the receiving cylinder between the observation hole and the cutting hole, and the airbag is communicated with an air pump fixedly installed on the lower plate surface of the material receiving plate through an air duct; a single material receiving hole, receiving cylinder, airbag, air pump, depth camera, cutting knife, and blanking hole cooperate to form a set of directional cutting components, and multiple sets of directional cutting components are cooperatively installed between the material receiving plate and the baffle plate.

[0024] As a further solution of the present invention: The feeding part includes a rice hopper installed on the support frame. At the outlet at the bottom of the rice hopper, a discharge pipe is connected and arranged. A guiding hole is opened on the pipe wall of the discharge pipe, and a throttle plate that can change the flow area of the discharge pipe by reciprocating movement is inserted in the guiding hole; A throttle telescopic rod is fixedly installed on the rice hopper through a fixing frame, and the throttle plate is fixedly installed on the telescopic end of the throttle telescopic rod; A guiding plate is fixedly installed below the discharge pipe, which can guide the indica rice falling from the discharge pipe to the material receiving plate.

[0025] As a further solution of the present invention: The collecting part includes a recycling box for receiving the indica rice that slides down from the material receiving plate. The recycling box is arranged below the falling trajectory of the material receiving plate; At the baffle plate, a germ end receiving box, a raw rice receiving box, and an indica rice receiving box that can alternately drive into the lower part of the falling trajectory of the falling hole are arranged; A base is arranged below the baffle plate. A horizontally arranged guide rail is fixedly installed on the base. The germ end receiving box, the raw rice receiving box, and the indica rice receiving box are slidably arranged on the guide rail along the length direction of the guide rail through guiding grooves opened on their box bottoms in sequence; The germ end receiving box, the raw rice receiving box, and the indica rice receiving box are fixedly connected to each other through connecting blocks in sequence, and a receiving telescopic rod that can push the germ end receiving box, the raw rice receiving box, and the indica rice receiving box to slide reciprocally along the guide rail is also arranged on the base. The telescopic end of the receiving telescopic rod is fixedly connected to one side of the germ end receiving box.

[0026] Compared with the prior art, the beneficial effects of the present invention are:

[0027] The starch in the endosperm is generally considered to present a uniform texture. The rice endosperm starch is polygonal starch granules with a uniform texture. These starch granules form large starch aggregates of multiple sizes and finally aggregate into amyloplasts, that is, endosperm cells. And as common general knowledge in this field, gramineous seeds do not have the ability to mobilize various endogenous enzymes for starch at the initial stage of germination. These endogenous enzymes are in an inhibited state. Only when germination starts and as germination progresses, with the mobilization of nutrients, α-amylase (which plays a role in the initial digestion of starch granules, breaking down starch from a granular form into a water-soluble form) is expressed and secreted from the scutellar tissue into the endosperm to initiate starch mobilization (Beck E, 1989).

[0028] As the main raw material for making rice noodles - indica rice, whole grains are currently used in the industry. Factories purchase finished indica rice and produce it according to mature processes such as cleaning - soaking - crushing / grinding → gelatinization → extrusion molding, and add food additives at the crushing / grinding stage as needed. In the prior art, the improvement of the quality of rice noodles mainly focuses on raw material compounding and processing technology improvement. For example, the improvement of the quality of rice noodles by studying the blending of pea starch, mung bean starch, etc. (YADAV B S et al., 2011; Wang Yonghui et al., 2014), or improving the grinding technology and studying the influence of wet grinding, semi - dry grinding and dry grinding processes on the properties of rice flour (Zhu Wenchang et al., 2018; Gao Xiaoxu et al., 2015), or improving the gelatinization temperature and improving the formation properties of starch gelatinization gel through the coordinated regulation of moisture and temperature (Ding Wenping et al., 2005), etc. There are few studies on whole - grain indica rice. Some studies have reported the changes in the physicochemical properties of indica rice during natural fermentation. Fermentation improves the tensile properties of rice flour and improves the texture and taste of rice flour (Li Lite et al., 2001; Lu Zhanhui et al., 2006).

[0029] Through a large number of studies, the inventors of this case first discovered that the starch texture in indica rice is not homogeneous. By performing microscopic structure characterization on indica rice, it was found that the starch molecular structure in the endosperm at the germ end is relatively loose, losing the starch morphology and scattering separately; or forming aggregates, and the surface of the aggregates undergoes enzymatic hydrolysis under the action of endogenous amylase to form a porous structure. After the amylase hydrolysis forms pores, it will cause the starch molecular chain to become shorter, thereby reducing the starch structure strength. Not only the amylose content decreases, but water molecules will also more easily enter the interior of the starch. When used to make rice noodles, it will result in the texture of the made rice noodles being too soft and without elasticity.

[0030] This invention breaks the inertial thinking in the industry. Based on the theory, starting from the internal starch structure of indica rice, by directly controlling the raw material indica rice, removing the loose starch near the germ, it is possible to improve the quality of the prepared rice noodles without adding other powders with high amylopectin content and food additives, and prepare rice noodles with Q - bounce, refreshing taste and non - sticky soup.

[0031] The rice noodles prepared by this preparation method not only have high quality and good taste, but also can be mass - produced without adjusting the existing rice noodle production line through the pre - treatment of indica rice, providing new ideas for the quality improvement, production and technical improvement of rice noodles, and having important significance for the rice noodle industry.

[0032] The device of the present invention can achieve the directional cutting of indica rice, that is, dividing indica rice into the germ end and raw rice, and thus can effectively reduce the influence of the germ end on the taste of rice noodles. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 It is a schematic diagram of the overall structure of the present invention.

[0034] Figure 2 It is a schematic diagram of the assembly structure of the material holding plate and the material blocking plate in the present invention.

[0035] Figure 3 It is a schematic diagram of the structure of the directional cutting component in the present invention.

[0036] Figure 4 It is a side view of the directional cutting portion in the present invention.

[0037] Figure 5 It is a cross-sectional view of the discharge pipe in the present invention.

[0038] Figure 6 It is a schematic structural diagram of the aggregate portion in the present invention.

[0039] Figure 7 It is the morphology of the cross section of the rice grain after long diameter longitudinal cutting, and B in the figure is an enlarged view of A.

[0040] Figure 8 Results of detailed characterization of different regions of the endosperm near the base of the germ in Indica rice.

[0041] Figure 9 Figure 2 is the chain length distribution of endosperm starch at the germ end and the back end of the germ of indica rice. In the figure, A is the relationship between the SEC weight distribution and the weight average molecular weight of starch at the back end of the germ, and B is the relationship between the SEC weight distribution and the weight average molecular weight of starch at the germ end.

[0042] Figure 10 This is a comparison diagram of the rice noodles prepared in Example 3.

[0043] Figure 11 This is a comparison diagram of the rice soup after cooking the rice noodles prepared in Example 3.

[0044] Figure 12 This is the low-field NMR result of the rice noodles prepared in Example 4.

[0045] In the figure: 1, feeding part; 11, rice bucket; 12, discharge pipe; 13, throttling telescopic rod; 131, throttling plate; 14, fixing frame; 15, guide plate; 16, support frame; 2, directional cutting part; 21, material holding plate; 211, material holding hole; 22, containing cylinder; 221, observation hole; 222, feed hole; 23, air pump; 231, air guide tube; 232, air bag; 24, depth phase machine; 25, baffle plate; 251, drop hole; 252, cutter; 253, slide; 26, cut telescopic rod; 27, slide rail; 28, baffle; 3, collection part; 31, recovery box; 32, germ end receiving box; 33, raw rice receiving box; 34, guide groove; 35, guide rail; 36, base; 37, receiving telescopic rod; 38, connecting block; 39, indica rice receiving box; 4, indica rice. DETAILED DESCRIPTION

[0046] The following will clearly and completely describe the technical solutions in the embodiments of the present invention with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0047] Please refer to Figures 1 to 6 , in the embodiments of the present invention, a preparation method of smooth and boil-resistant rice noodles and a device for obtaining raw rice for preparing the rice noodles include a feeding part 1 for storing indica rice and quantitatively providing the indica rice to downstream processing equipment. At the discharge port of the feeding part 1, there is an orientation cutting part 2 for receiving the indica rice and cutting off the germ end of the indica rice. At the outlet of the orientation cutting part 2, there is an aggregate part 3 for receiving the indica rice after the germ end is cut off.

[0048] As Figure 1 and Figure 4 shown, the feeding part 1 includes a support frame 16 fixedly installed on the ground. At the top of the support frame 16, there is a rice hopper 11 for loading rice, and the rice hopper 11 is in the shape of a funnel with a large top and a small bottom. At the outlet at the bottom of the rice hopper 11, there is a discharge pipe 12 connected. The cross-section of the discharge pipe 12 is rectangular. And on the outer pipe wall of the discharge pipe 12, there are guide holes, and a throttle plate 131 whose shape matches that of the discharge pipe 12 to change the flow area of the discharge pipe 12 is inserted into the guide holes. The flow rate of the rice discharged from the rice hopper 11 is controlled by changing the flow area. On the rice hopper 11, there is a throttle telescopic rod 13 fixedly installed through a fixing frame 14. The throttle telescopic rod 13 is a conventional electric telescopic rod, and its telescopic process is controlled by an electric signal. The throttle plate 131 is fixedly installed on the telescopic end of the throttle telescopic rod 13. Thus, under the control of the throttle telescopic rod 13, the throttle plate 131 is pushed to move in the lumen of the discharge pipe 12, so as to achieve the purpose of controlling the discharge flow rate of the rice hopper 11.

[0049] A guide plate 15 for guiding the indica rice falling from the discharge pipe 12 to a receiving plate 21 is fixedly installed below the discharge pipe 12. The guide plate 15 is a U-shaped plate with a flat middle and upturned sides, and the indica rice slides into the receiving plate 21 in the U-shaped groove formed on it.

[0050] As Figures 1 to 4 shown, the orientation cutting part 2 mainly includes a receiving plate 21, a receiving cylinder 22, a cutting knife 252, an airbag 232, a depth camera 24, and a baffle 25.

[0051] The plate surface of the flat material receiving plate 21 is arranged to incline downward, and its high-position end is located below the blanking trajectory of the material guiding plate 15 so as to receive the indica rice sliding down from the material guiding plate 15. A plurality of material receiving holes 211 are penetrated and opened on the upper plate surface of the material receiving plate 21, and the material receiving holes 211 cooperate with each other and are distributed on the material receiving plate 21 in a rectangular array manner. The axes of the material receiving holes 211 are all perpendicular to the plate surface of the material receiving plate 21.

[0052] As Figure 2 and Figure 3 shown, a plurality of receiving cylinders 22 are arranged in sequence on the lower plate surface of the material receiving plate 21, and each receiving cylinder 22 is coaxially communicated with the corresponding material receiving hole 211. The material receiving hole 211 can be set in a converging shape with a larger upper part and a smaller lower part, and its minimum diameter is the same as the inner diameter of the receiving cylinder 22, so that the indica rice can slide into the receiving cylinder 22 more easily. Since the average diameter of the indica rice is about 4 mm and the length is about 7 mm, the depth of the receiving cylinder 22 is set to 9 mm and the inner diameter is set to 6 mm, so that only one indica rice can be accommodated in one receiving cylinder 22 at the same time.

[0053] An observation hole 221 for observing the end type of the indica rice from the outside to the inside is opened on the cylinder wall of the receiving cylinder 22. A depth camera 24 for collecting an image of the end of the indica rice through the observation hole 221 and identifying the end type of the indica rice is arranged outside the observation hole 221. The depth camera 24 is fixedly installed on the lower plate surface of the material receiving plate 21. Before using the device, different indica rices are inserted into the receiving cylinders 22 in sequence, and then the depth camera 24 is used to take pictures of the upper end of the indica rice when it is located in the receiving cylinder 22 through the observation hole 221. A neural network prediction model is trained according to the pictures and the types corresponding to the ends of the indica rice in the pictures, and the trained neural network prediction model is stored in the control terminal. The control terminal controls the inflation and deflation of the airbag 232 according to the recognition result. An airbag 232 for inflating and squeezing the middle part of the indica rice to squeeze the indica rice tightly against the cylinder wall of the receiving cylinder 22 or deflating to eliminate the squeezed state of the indica rice according to the recognition result of the depth camera 24 is also installed in the receiving cylinder 22. The airbag 232 is installed on the cylinder wall of the receiving cylinder 22 between the observation hole 221 and the cutting hole 222, and the airbag 232 is communicated with an air pump 23 fixedly installed on the lower plate surface of the material receiving plate 21 through an air duct 231. A cutting hole 222 is also opened on the cylinder wall of the receiving cylinder 22, and both the observation hole 221 and the cutting hole 222 are opened on the same side of the receiving cylinder 22, with the observation hole 221 above and the cutting hole 222 below.

[0054] A material blocking plate 25 that can block the lower port of the accommodating cylinder 22 is arranged on the lower end surface of the accommodating cylinder 22 in a reciprocating radial sliding manner along the accommodating cylinder 22. A material dropping hole 251 is formed through the material blocking plate 25, and the material dropping hole 251 can communicate with or be misaligned with the cavity of the accommodating cylinder 22 during the reciprocating sliding of the material blocking plate 25, so that the indica rice can fall or stay in the accommodating cylinder 22. A cutting knife 252 is fixedly installed on the material blocking plate 25, and the cutting knife 252 can enter the cutting hole 222 and cut off the germ end of the indica rice when the material blocking plate 25 makes a sliding motion that misaligns the material dropping hole 251 with the cavity of the accommodating cylinder 22. A slide rail 27 that is arranged obliquely in the same direction as the material receiving plate 21 is installed on the support frame 16. A chute 253 that can be embedded with the slide rail 27 and forms a sliding fit with the slide rail 27 is formed on the lower plate surface of the material blocking plate 25. Above the slide rail 27, a cutting telescopic rod 26 with a telescopic direction parallel to the inclined direction of the slide rail 27 is also installed on the support frame 16. The material blocking plate 25 is fixedly installed at the telescopic end of the cutting telescopic rod 26. The cutting telescopic rod 26 is a conventional electric telescopic rod, and its telescopic process is controlled by an electric signal.

[0055] In order to prevent the indica rice on the material receiving plate 21 from splashing due to collision, baffles 28 are arranged around the material receiving plate 21 in the front, back, left, and right directions. An inlet for inserting the guide plate 15 is formed on the baffle 28 at the rear side of the material receiving plate 21, and an outlet for the indica rice to slide out of the material receiving plate 21 is formed on the front side of the material receiving plate 21.

[0056] A single material receiving hole 211, accommodating cylinder 22, air bag 232, air pump 23, depth camera 24, cutting knife 252, and material dropping hole 251 cooperate to form a set of directional cutting components, and multiple sets of directional cutting components are cooperatively installed between the material receiving plate 21 and the material blocking plate 25.

[0057] As Figure 1 and Figure 6 shown, the aggregate part 3 includes a recovery box 31 for receiving the indica rice that slides down from the material receiving plate 21, and the recovery box 31 is fixedly arranged below the falling trajectory of the material receiving plate 21.

[0058] A base 36 is arranged below the material blocking plate 25. A horizontally arranged guide rail 35 is fixedly installed on the base 36. The germ end receiving box 32, raw material rice receiving box 33, and indica rice receiving box 39 are slidably arranged on the guide rail 35 along the length direction of the guide rail 35 in sequence through guide grooves 34 formed in their box bottoms. The germ end receiving box 32, raw material rice receiving box 33, and indica rice receiving box 39 are fixedly connected to each other through connecting blocks 38 in sequence, and a material receiving telescopic rod 37 that can push the germ end receiving box 32, raw material rice receiving box 33, and indica rice receiving box 39 to slide reciprocally along the guide rail 35 is also arranged on the base 36. The telescopic end of the material receiving telescopic rod 37 is fixedly connected to one side of the germ end receiving box 32. The material receiving telescopic rod 37 is a conventional electric telescopic rod, and its telescopic process is controlled by an electric signal.

[0059] When the device of the present invention is used, firstly, a certain amount of two indica rice is loaded into the rice bucket 11, and then an electric signal is transmitted to the throttling telescopic rod 13 through the control terminal, and the throttling telescopic rod 13 is started, driving the throttling plate 131 to gradually move outward to open the discharge pipe 12. The indica rice falls onto the guide plate 15 along the discharge pipe 12, and slides onto the material holding plate 21 along the guide plate 15. At this time, the accommodating tube 22 and the drop hole 251 are misaligned with each other under the control of the cut-off telescopic rod 26. The indica rice slides on the material holding plate 21 and gradually slides into the accommodating tube 22, and the excess indica rice slides into the recovery box 31 for subsequent use. When the throttling plate 131 is opened for a set time, the control terminal controls the throttling telescopic rod 13 to extend and close the discharge pipe 12. Then, the ends of the indica rice in each accommodating tube 22 are photographed by the corresponding depth cameras 24, and the photographed photos are uploaded to the control terminal, and the control terminal issues corresponding instructions according to the recognition results. When the recognition result is a non-germ end, it indicates that the end located in the cutter hole 222 is a germ end, which needs to be cut off. At this time, the air bag 232 in the corresponding accommodating tube 22 is inflated, and the air bag 232 is pressed against the middle of the indica rice, thereby squeezing the indica rice into the accommodating tube 22. When the recognition result is a germ end or no indica rice, the indica rice is small or the current accommodating tube 22 does not insert indica rice, and the air bag 232 in the current accommodating tube 22 is not inflated at this time, so that the air bag 232 remains in a shrunken state. Then the control terminal controls the material receiving telescopic rod 37 to work, and pushes the indica rice receiving box 39 to the bottom of the material dropping track of the blanking hole 251, and then the control terminal controls the extension of the cutting telescopic rod 26 to make the accommodating tube 22 and the blanking hole 251 communicate with each other, and at this time, the indica rice without the squeezing effect of the air bag 232 will fall into the indica rice receiving box 39. Afterwards, the control terminal controls the cutting telescopic rod 26 to shorten, so that the cutter 252 enters the barrel cavity of the accommodating tube 22 through the knife feed hole 222, and cuts off the germ end of the indica rice. Then the control terminal controls the material receiving telescopic rod 37 to work, pushes the germ end receiving box 32 to the bottom of the material dropping track of the drop hole 251, and then controls the cutting telescopic rod 26 to extend. At this time, since the germ end is larger than the diameter of the knife feed hole 222, the cut germ end will remain in the accommodating tube 22. When the accommodating tube 22 and the drop hole 251 are connected to each other again, the germ end falls from the drop hole 251 to the germ end receiving box. Then the control terminal controls the material receiving telescopic rod 37 to work, pushes the raw material rice receiving box 33 to the bottom of the material dropping track of the dropping hole 251, and then controls all the air pumps 23 to extract the gas in the corresponding airbags 232, so that each airbag 232 is in a deflated state, and the remaining raw material rice in the accommodating cylinder 22 will fall into the raw material rice receiving box 33, so that the raw material rice of the current round is prepared. According to the above steps, a sufficient amount of raw material rice can be obtained in a cycle.

[0060] Example 1

[0061] Characterization of Indica Rice Microstructure

[0062] The indica rice selected for the experiment was the certified variety Shuangyahei No. 1, an indica glutinous rice.

[0063] Indica rice is the caryopsis of indica rice after removing the glumes (inner glume, outer glume) and lemma. The indica rice is 9.20 mm long and 3.12 mm wide. The black rice grains are 6.15 mm long and 2.51 mm wide.

[0064] Under a stereomicroscope, it can be clearly seen that the embryo is located at the base of the ventral side of the rice grain, oval in shape, with a complete structural morphology, and is protected by the lemma.

[0065] Analysis was performed on the mm-um-nm scale using a cold field emission ultra-high resolution electron microscope HITACHI SU8600 and a laser confocal microscope Olympus FV1000.

[0066] Longitudinally cut along the major axis of the rice grain, and the morphological structure is as Figure 7 shown. Fine characterization of different regions of the endosperm near the bottom of the germ was carried out, and the results are as Figure 8 shown.

[0067] It can be seen that the starch structure near the germ end is more porous. The starch in the endosperm cells in this region has two morphological characteristics:

[0068] 1) Central endosperm cells ( Figure 8 in A) are scattered individually; losing the complete starch morphology and undergoing a sufficient enzymatic reaction;

[0069] 2) Large starch granules in the outer endosperm cells. Those near the bottom end ( Figure 8 in B) still retain the starch granule morphology, but are relatively loose, and at the same time, enzymatic reaction occurs on the surface to form porous starch granules. The starch granules at the far end of the embryo ( Figure 8 in C) are smooth and compact on the surface.

[0070] Example 2

[0071] The tested indica rice variety was Liangyou 6176 (LY6176). An appropriate amount of indica rice was taken, and the endosperm near the germ part of each indica rice grain (accounting for 1 / 3 - 1 / 5 of the grain length) was cut off, collected, and denoted as sample LY6176-g. The remaining endosperm was collected and denoted as sample LY6176. They were respectively ground and purified to obtain starch, and biological analysis was performed on the starch.

[0072] 1. Molecular weight detection

[0073] Weigh 5 mg of purified starch, add 5 mL of mobile phase DMSO, heat and dissolve at 80 °C for 3 h, and then inject it into the instrument. The chromatographic system uses a gel permeation chromatography - differential refractive index - multi - angle laser light scattering system. The liquid phase system is U3000 (Thermo, USA), the differential refractive index detector is Optilab T - rEX (Wyatt technology, CA, USA), the laser light scattering detector is DAWN HELEOSⅡ (Wyatt technology, CA, USA), and λ = 663.7 nm.

[0074] According to the properties of the compound, use gel exclusion chromatography columns with appropriate molecular weight ranges (Ohpak SB - 805HQ(300×8 mm), Ohpak SB - 804HQ(300×8 mm), Ohpak SB - 803HQ(300×8 mm)); the column temperature is 60 °C; the injection volume is 200 μl; the mobile phase A (0.5% LiBr, DMSO); the flow rate is 0.3 ml / min; the elution gradient: isocratic for 120 min; DMSO solution: dn / dc value is 0.07 mL / g.

[0075] The molecular weight results are shown in Table 1. In the table, Mn is the number - average molecular weight, Mp is the peak molecular weight, Mz is the Z - average molecular weight, and Mw is the weight - average molecular weight. It can be seen that the molecular weight of the starch at the germ end is less than that of the endosperm starch at the rear end of the germ.

[0076] Table 1 Molecular weight results

[0077]

[0078] 2. Degree of branching detection

[0079] Weigh an appropriate amount of purified starch (about 5 mg) into an imported EP tube, add 1 mL of D6 - DMSO, heat overnight at 80 °C; centrifuge at 12000 rpm for 10 min, take the supernatant and add it to the NMR tube for on - machine detection. Use the 1H nuclear magnetic resonance analysis method to detect the degree of branching distribution of the sample. The instrument used is Bruker BioSpin GmbH, the number of scans is 32, the resonance radio frequency is 500.23 MHz, and the NMR spectrum is 1H.

[0080] Use MestReNova software to analyze the data. According to the peak emergence time of the sample, select the peak emergence range to obtain the final result. Calculate using the following formula:

[0081]

[0082] DB: Degree of branching; A: Peak area of α - 1,6 bond; B: Peak area of α - 1,4 bond.

[0083] The results are shown in Table 2. It can be seen that the degree of starch branching at the germinal end is higher than that of the endosperm starch at the posterior end of the germ.

[0084] Table 2 Results of the degree of branching

[0085]

[0086] 3. Chain length distribution

[0087] Preparation of standard: Weigh 5 mg each of DP4 - DP7 from the oligosaccharide standard set (Sigma) and resuspend in 5 mL of double-distilled water. Boil in a water bath for 60 min, vortexing intermittently for mixing; add 50 μL of sodium acetate (0.6 M, pH 4.4), NaN3 (10 μL, 2% w / v) and 10 μL of isoamylase (1400 U), incubate at 37 °C for 24 h. Add 0.5% (w / v) sodium borohydride solution, vortex and let stand for 20 h. Take 600 μL and place in a centrifuge tube, dry under nitrogen at room temperature. Dissolve in 30 μL of 1 M NaOH for 60 min, then add 570 μL of water for dilution, centrifuge at 12000 rpm for 5 min, and take the supernatant for sample loading.

[0088] Weigh an appropriate amount of purified starch (about 10 mg), resuspend in 5 mL of water, boil in a water bath for 60 min, vortexing intermittently for mixing; add 50 μL of sodium acetate (0.6 M, pH 4.4), NaN3 (10 μL, 2% w / v) and 10 μL of isoamylase (1400 U), incubate at 37 °C for 24 h. Add 0.5% (w / v) sodium borohydride solution, vortex and let stand for 20 h. Take 600 μL and place in a centrifuge tube, dry under nitrogen at room temperature. Dissolve in 30 μL of 1 M NaOH for 60 min, then add 570 μL of water for dilution, centrifuge at 12000 rpm for 5 min, and take the supernatant for sample loading.

[0089] The chromatographic system used is the Thermo ICS5000 ion chromatography system (ICS5000 +, Thermo Fisher Scientific, USA), and an electrochemical detector is used to analyze and detect starch. Using Dionex TM CarboPac TMPA200 (250 * 4.0 mm, 10 um) liquid chromatography column, with an injection volume of 5 μL. Mobile phase A: 0.2 M NaOH; Mobile phase B: 0.2 M NaOH / 0.2 M NaAC, column temperature is 30 °C, and an electrochemical detector is used to analyze and detect components. Flow rate is 0.4 mL / min; Elution gradient: 0 min A / B (90:10 V / V), 10 min A / B (90:10 V / V), 30 min A / B (40:60 V / V), 50 min A / B (40:60 V / V); 50.1 min A / B (90:10 V / V); 60 min A / B (90:10 V / V).

[0090] The results are shown in Table 3 and Figure 9 , Figure 9 where A is the chain length distribution of LY6176, and B is the chain length distribution of LY6176-g.

[0091] Table 3 Chain length distribution data (ICS)

[0092]

[0093] It can be seen that the amylose content (peak3_area%) of the starch near the germ end is higher than that of the endosperm starch at the back end of the germ.

[0094] Example 3

[0095] Use intact indica rice and indica rice with the endosperm near the germ part removed respectively to make rice noodles according to the same process.

[0096] The preparation process is as follows:

[0097] First, take 50 g of each of the two types of indica rice flour and mix it with 50 mL of boiling water to knead into a dough. After sealing and standing the formed dough for 30 minutes, steam it with boiling water for 20 min. Finally, extrude it into cylindrical rice noodles using a noodle press M2-MS180 with a 2.6 mm hole mold.

[0098] The morphology of the prepared rice noodles is as Figure 10 shown. It can be seen that the difference between the two is significant. For the rice noodles prepared by this method (B in the figure), due to the denser starch in the endosperm part, the crystallinity of the extruded rice noodles is higher. While for the ordinary rice noodles (A in the figure), due to the existence of more starch with short molecular chains and low crystallinity, the structure of the formed rice noodles is loose, and they are softer and lighter in color visually.

[0099] Take 100 g of the pre-soaked rice noodles respectively and put them into 400 mL of boiling water and cook for 3 min. The comparison diagram of the rice soup can be seen in Figure 11The rice noodles prepared by this method (right in the picture) have a higher degree of crystallinity because the starch molecular chains in the endosperm are longer and more complete, making the rice noodles more resistant to cooking, not mushy in the soup, and chewy (Q-elastic). The soup of ordinary rice noodles (left in the picture) is turbid after cooking because the starch molecules with short molecular chains are not easy to recrystallize, resulting in a loose structure of the formed rice noodles.

[0100] Example 4

[0101] Based on Example 3, rice noodles were prepared according to different moisture ratios (water-W, germ end rice flour-RF), and the viscosity, chewiness, hardness and other data of the rice noodles were measured using a texture analyzer, as shown in Table 4 below.

[0102] Table 4 Properties of rice noodles prepared with different moisture ratios

[0103]

[0104] In the process of making rice noodles, moisture content is an important process parameter, which directly affects the texture characteristics of rice noodles. The results in Table 4 show that moisture content affects the texture characteristics of rice noodles, and its hardness, elasticity, adhesiveness and chewiness gradually decrease with the increase of water addition. This may be because moisture content can affect the gelatinization degree of starch, thereby affecting the texture characteristics of rice noodles. Specifically, there is a close relationship between moisture content and the texture characteristics of rice noodles, such as hardness, elasticity, and adhesiveness. Appropriate moisture content can make rice noodles form a tighter network structure during the cooking process, thereby improving the texture characteristics of rice noodles. On the contrary, if the moisture content is too low or too high, it may cause the rice noodles to break or become too soft during the cooking process, thereby affecting its texture characteristics and taste. In summary, moisture content is one of the key factors affecting the texture characteristics of rice noodles. By adjusting the moisture content between 7:10 and 8:10 (i.e., 70-80wt%), the texture characteristics of rice noodles can be effectively improved and their edible quality can be improved.

[0105] Figure 12 The low-field NMR results of rice noodles were obtained by low-frequency NMR (LF-NMR) experiment to obtain the signal for measuring the transverse relaxation time (T2). The relaxation spectrum is shown in Figure 12 This spectrum provides information about the proton distribution and is mainly used to measure the T2 relaxation time, which is related to the water distribution in the sample. Based on the relaxation time, it can be divided into two groups of water: one is the lower T2 range of ~50ms (labeled as T 21 ) is classified as tightly bound water, and the other is in the higher range of ~800 ms (labeled as T 22 ) is classified as weakly bound water. Figure 12 It can be seen that the T2 signal is mainly concentrated in the range of ~100ms, which is mainly tightly bound water. As the water content increases, T 21The proportion gradually decreases, T 22 The proportion gradually increases, indicating that the mobility of water in the rice noodle sample system prepared with a low water content is poor, and it interacts tightly with macromolecular substances (such as starch, protein, etc.) in the non-aqueous components. As the water content increases, the ordered structure inside the starch granules is destroyed, more long-chain starches break into short-chain starches, the degree of freedom of the starch segments increases, the effective entanglement decreases, the mobility of water molecules increases, and they interact with molecules such as starch in the form of weakly bound water. Therefore, there is a tendency for the signal to shift to the right.

[0106] As described above, it is only the preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art within the technical scope disclosed by the present invention, according to the technical solution and inventive concept of the present invention, makes equivalent substitutions or changes, and should be covered within the protection scope of the present invention.

Claims

1. A method for preparing smooth and resistant rice noodles, characterized in that: The following steps are involved: S1, using a rice milling machine to mill indica rice to obtain indica rice; S2, removing the endosperm at the embryo end of the indica rice, wherein the endosperm at the embryo end accounts for 1 / 5 to 1 / 8 of the total length of the indica rice, and the indica rice after the endosperm at the embryo end is removed is called raw rice; S3, processing the raw rice by squeezing powder to obtain the required rice noodles.

2. The method for preparing the smooth and boiling-resistant rice noodles according to claim 1, characterized in that: The steps of squeezing out the rice powder include soaking the raw rice, crushing and grinding, gelatinization, extrusion molding, freezing and drying.

3. The method for preparing the smooth and boiling-resistant rice noodles according to claim 2, characterized in that: The gelatinization and extrusion molding steps are completed in a screw extruder. The raw rice slurry obtained by grinding is put into the screw extruder. The raw rice slurry is heated and gelatinized in the screw extruder, and is sprayed out from a perforated panel arranged at the outlet end of the screw extruder to form rice noodles with a circular cross-section.

4. A device for obtaining raw rice, the device being applied to the method for preparing a smooth and resistant rice noodle as claimed in claim 1, 2 or 3, characterized in that: The device comprises a feeding part (1) for storing indica rice and providing the indica rice to downstream processing equipment in a quantitative manner; a directional cutting part (2) for receiving the indica rice and cutting off the endosperm at the germ end of the indica rice is arranged at the discharge port of the feeding part (1); and a collecting part (3) for receiving the indica rice after the endosperm at the germ end is cut off is installed at the outlet of the directional cutting part (2); The directional cutting portion (2) comprises a receiving tube (22) for receiving the falling indica rice, and the tube cavity of a single receiving tube (22) can only accommodate one indica rice whose length direction extends along the axial direction of the receiving tube (22); A material blocking plate (25) capable of blocking a lower end of the accommodating tube (22) is arranged on the lower end surface of the accommodating tube (22) in a radially reciprocating manner along the accommodating tube (22), and the material blocking plate (25) is provided with a material dropping hole (251) which can be communicated with or displaced with the tube cavity of the accommodating tube (22) during the reciprocating sliding of the material blocking plate (25) so that the indica rice falls or is retained in the accommodating tube (22); an observation hole (221) capable of observing the end of the indica rice from the outside to the inside is provided on the tube wall of the accommodating tube (22), and a material receiving hole (221) capable of collecting an image of the end of the indica rice and identifying the end of the indica rice is arranged outside the observation hole (221). a depth camera (24) of the type used for the rice; an air bag (232) is also installed in the accommodating tube (22), which can be inflated and squeezed to squeeze the middle part of the indica rice on the tube wall of the accommodating tube (22) or deflated to eliminate the squeezed state of the indica rice according to the recognition result of the depth camera (24); a knife feed hole (222) is also opened on the tube wall of the accommodating tube (22); a cutter (252) is fixedly installed on the baffle plate (25); the cutter (252) can enter the knife feed hole (222) and cut off the endosperm of the germ end of the indica rice when the baffle plate (25) slides to make the drop hole (251) and the tube cavity of the accommodating tube (22) misaligned with each other; The directional cutting portion (2) comprises a material receiving plate (21) arranged with its plate surface tilted downward, a material receiving hole (211) penetrating through the upper plate surface of the material receiving plate (21), and the axis of the material receiving hole (211) and the plate surface of the material receiving plate (21) are perpendicular to each other; a containing cylinder (22) is fixedly mounted on the lower plate surface of the material receiving plate (21), and the containing cylinder (22) and the material receiving hole (211) are coaxially connected and arranged with each other; A slide rail (27) is installed on the support frame (16) and is arranged in an inclined direction in the same direction as the material receiving plate (21). A slide groove (253) is provided on the lower plate surface of the material blocking plate (25) for the slide rail (27) to be embedded and to form a sliding fit with the slide rail (27). A cutting telescopic rod (26) whose telescopic direction is parallel to the inclination direction of the slide rail (27) is also installed on the support frame (16) on the upper side of the slide rail (27). The material blocking plate (25) is fixedly installed on the telescopic end of the cutting telescopic rod (26). The observation hole (221) and the knife feed hole (222) are both opened on the same side of the accommodating tube (22), and the observation hole (221) is at the top and the knife feed hole (222) is at the bottom; the depth camera (24) is fixedly mounted on the lower plate surface of the material holding plate (21); the air bag (232) is mounted on the wall of the accommodating tube (22) between the observation hole (221) and the knife feed hole (222), and the air bag (232) is connected to the air pump (23) fixedly mounted on the lower plate surface of the material holding plate (21) through the air guide tube (231); the single material holding hole (211), the accommodating tube (22), the air bag (232), the air pump (23), the depth camera (24), the cutter (252), and the blanking hole (251) cooperate to form a set of directional cutting components, and multiple sets of directional cutting components are cooperatively mounted between the material holding plate (21) and the material blocking plate (25).

5. The device for obtaining raw rice according to claim 4, characterized in that: The feeding part (1) comprises a rice hopper (11) mounted on a support frame (16); a discharge pipe (12) is arranged at an outlet at the bottom of the rice hopper (11); a guide hole is provided on the wall of the discharge pipe (12); a throttle plate (131) is inserted into the guide hole and can change the flow area of ​​the discharge pipe (12) by reciprocating movement; a throttle telescopic rod (13) is fixedly mounted on the rice hopper (11) via a fixing frame (14); the throttle plate (131) is fixedly mounted on the telescopic end of the throttle telescopic rod (13); and a guide plate (15) is fixedly mounted below the discharge pipe (12) and can guide the indica rice dropped from the discharge pipe (12) to a material receiving plate (21).

6. The device for obtaining raw rice according to claim 5, characterized in that: The material collecting section (3) comprises a recovery box (31) for receiving the indica rice that slides down from the material receiving plate (21), and the recovery box (31) is arranged below the material dropping track of the material receiving plate (21); a germ end endosperm receiving box (32), a raw material rice receiving box (33) and an indica rice receiving box (39) are arranged at the material blocking plate (25) and can alternately enter the material dropping hole (251) below the material dropping track; a base (36) is arranged below the material blocking plate (25), and a horizontally arranged guide rail (35) is fixedly mounted on the base (36), and the germ endosperm receiving box (32), the raw material rice receiving box (33) and the indica rice receiving box (39) are arranged below the material blocking plate (25). The boxes (39) are slidably arranged on the guide rail (35) in sequence along the length direction of the guide rail (35) through guide grooves (34) provided on the bottom of the boxes; the germ end endosperm receiving box (32), the raw material rice receiving box (33) and the indica rice receiving box (39) are fixedly connected to each other in sequence through connecting blocks (38); and a material receiving telescopic rod (37) is further arranged on the base (36) for pushing the germ end endosperm receiving box (32), the raw material rice receiving box (33) and the indica rice receiving box (39) to reciprocate along the guide rail (35); the telescopic end of the material receiving telescopic rod (37) is fixedly connected to one side of the germ end endosperm receiving box (32).

Images