TW201813526A - Preparation method of puffed dried rice as instant food product characterized by having advantages of good rehydration, perfect rice grain and good mouthfeel - Google Patents

Abstract

The present invention relates to a preparation method of puffed dried rice, comprising: performing a first drying to the rice; adding a liquid modification agent and performing a stirring and mixing process to make the surface of rice coated with liquid modification agent; then, performing a second drying; and finally, using hot air to perform a puffing and drying process, so as to obtain instant rice with bulk density of 0.2-0.6g/mL after cooling down.

Description

   Bulky dry rice as instant food and preparation method thereof   

The invention relates to a method for preparing bulging dry rice as a fast food product.

Taiwan Patent Application Publication No. 201446151 A (equivalent to JP2014-158423 A and CN105050424A) discloses a kind of instant food placed in a container, which can be eaten by injecting only hot water or injecting hot water or water and then heating it in a microwave oven. It is characterized in that the swollen and dry rice submerged in water is contained in a container. The instant food in the previous case can be used to visually inspect the water surface in the container by sinking the used dry rice into the water. The preferred pseudo-density of the swollen dry rice sunk into the water is 0.55 g / mL or more. The method for preparing the expanded dry rice disclosed in the previous case, as described in Comparative Example 1, includes washing and draining 700 g of white rice, adding the following ratios to refined white rice (emulsified fat 14 g / kg, sucrose fatty acid ester 3 g / kg, polymerization Phosphate 0.3g / kg), and mix uniformly. It was boiled for 15 minutes using a rice cooker (Rinai, gas cooker RR-10KS) with a water content of 85% of rice mass. After steaming for 20 minutes, you can get cooked rice with 50% moisture after cooking. Let it air cool and loosen. The loosened cooked rice was stored in a drying room, and was dried at 25 ° C. and a wind speed of 3 to 4 m / s for 25 minutes until the moisture content became 26% by mass. Leave it for 30 minutes after one drying, and then place it on the screen to remove the tangled serious part. Thereafter, it was flattened by passing between rollers having a roller interval of 0.35 mm. The flattened pressed rice was stored in a drying room, and was subjected to secondary drying at 80 ° C and a wind speed of 3 to 4 m / s for 15 minutes until the moisture content was 16%. It was left for 30 minutes after the secondary drying, and then the secondary dried rice was stored in a high-temperature air-drying machine capable of high-temperature air jetting at high speed, and subjected to bulging drying at 190 ° C and a wind speed of 50 m / s for 30 seconds. By this expansion and drying, the rice is expanded, and an expanded rice with a moisture content of about 8% is obtained. This expanded dry rice was placed on a sieve to remove broken rice and unexpanded rice. The remaining expanded rice was measured to have a false density of 0.43 g / mL. In addition to the method for preparing the expanded dry rice disclosed in the previous example 1, in addition to adding more water during cooking, the moisture after cooking is increased, and the temperature during the expansion and drying is reduced to less than 160 ° C The same operation as in Comparative Example 1 was carried out except that the secondary dried rice was bulged and dried while steam was blown in to obtain a flared dried rice having a false density of 0.60 g / mL.

In the previous method, the first dried rice had to be flattened through the drum interval, which increased its fixed cost and took time and labor.

A main object of the present invention is to provide a method for preparing expanded dry rice, which does not require a flattening step in the prior art.

Another object of the present invention is to provide a method for preparing expanded dry rice. The prepared expanded rice has the advantages of good rehydration, complete rice grains and good taste.

Yet another object of the present invention is to provide a dry and expanded rice, which has the advantages of good rehydration, complete rice grains and good taste.

A method for preparing bulky dried rice completed in accordance with the present invention includes the following steps: first drying the cooked rice to a moisture content of 25-40% by weight; changing the first dried rice to a liquid Stir and mix the agents so that the surface of the rice is coated with the liquid modifier; dry the rice coated with the liquid modifier for a second time to a moisture content of 3-12 wt%; and dry the rice for the second time Hot air expansion is performed to obtain expanded dry rice with a water content of 0.9-2.9% by weight after cooling, wherein 2.5-20 mL of the liquid modifier is added to each 100 grams of the first dried rice. The liquid modifier contains: 0.5-5 grams of polysaccharide; 0.5-10 grams of emulsifier; 1-5 grams of edible oil; and the balance of water, wherein when the emulsifier is fatty acid glyceride, the liquid modifier The modifier may not contain the edible oil.

Preferably, the polysaccharide is a plant polysaccharide.

Preferably, the polysaccharide is pullulan.

Preferably, the polysaccharide is carboxymethyl cellulose-sodium.

Preferably, the polysaccharide is modified starch.

Preferably, the emulsifier is an emulsifier having an HLB value of 3-6.

Preferably, the emulsifier is a sucrose ester, a fatty acid glyceride, a fatty acid sorbose ester, or a fatty acid propylene glycol ester.

Preferably, the emulsifier is a sucrose ester.

Preferably, the emulsifier is a fatty acid glyceride.

Preferably, the edible oil is soybean oil.

Preferably, 5-10 mL of the liquid modifier is added to every 100 grams of the first dried rice.

Preferably, the first drying is performed with hot air at about 40 ° C.

Preferably, the second drying is performed with unheated air or cold air.

Preferably, the hot air expansion is performed with hot air at an outlet temperature of 300-550 ° C, and the temperature of the hot air when it contacts the second dried rice is 150-200 ° C.

Preferably, the duration of the hot air expansion is 6-12 seconds.

The present invention provides a bulky dry rice, which has a false density of 0.2-0.6 g / mL and a porosity of 45-90%.

Preferably, the puffed dry rice has a whiteness of 75-80.

Preferably, the surface of the bulged dry rice has a plurality of channels, and the inside of the bulged dry rice has a porous structure.

Preferably, the puffed dry rice has a moisture content of 0.9 to 7.7%.

R101‧‧‧ polished white rice

R103‧‧‧Cleaning

R105‧‧‧Immersion

R107‧‧‧drain

R109‧‧‧Steam cook

R111‧‧‧ dispersed rice

R113‧‧‧hot air drying

R115‧‧‧ The first dried rice

R117‧‧‧ Spraying or pouring conditioner

R119‧‧‧cold air drying

R121‧‧‧ Second dried rice

R123‧‧‧Hot air

R125‧‧‧Swelled Dry Rice

FIG. 1 is a flow block diagram of a method for preparing expanded dry rice according to a preferred embodiment of the present invention.

Figures 2 (A) and 2 (B) respectively show the bulging dry rice (R125) (A) prepared according to Example 4 of the present invention and the scanning formula of the surface before bulging (R121) (B) Scanning electron microscope (SEM) photograph, magnification 35X.

3 (A) and 3 (B) are scanning electron microscopes showing the cross section of the expanded dry rice (R125) (A) prepared in Example 4 and before the expansion (R121) (B). (scanning electron microscope, SEM) photograph, magnification 35X.

The invention discloses a novel method for preparing bulging dry rice, which comprises mixing and mixing the liquid modifier with the first dried rice to uniformly apply the liquid modifier on the surface of the rice grains; The moisture content of the previously dried rice was relatively low. In the present invention, the surface of the rice particles is modified to stabilize the structure of the rice particles at the time of swelling, so that the water inside the rice particles is blocked at the initial stage of hot air swelling and quickly absorbs heat to form water vapor swelling. Therefore, the method of the invention can use low water The second dried rice is hot-air-expanded to shorten the time of expansion, and the obtained dried-expanded rice has a completely gelatinized surface layer and a partially gelatinized core with a porous structure, and has good rehydration. And the rice grains are complete and taste good.

The present invention provides a dry and expanded rice, which has a false density of 0.2 to 0.6 g / mL and a whiteness of 75 to 80. The specific embodiment is that after the polished white rice is washed, it is soaked with water to absorb 0.1 to 0.4 times the weight of water, preferably 0.2 to 0.3 times the weight; the water-absorbing rice grains drain the excess water. The cooked rice is spread evenly on a stainless steel plate, and the first drying is performed with hot air at 40 ° C, the wind speed is 50 ~ 250m / min, and the time is 20 ~ 30 minutes, until the moisture content of the rice is about 25 ~ 40%, and sprayed Add 2.5 to 20 mL of a liquid modifier to every 100 grams of the first-dried rice. The liquid modifier contains: 0.5 to 5 grams of polysaccharide; 0.5 to 10 grams of emulsifier; and 1 to 5 Grams of edible oil; and the balance of water, wherein when the emulsifier is a fatty acid glyceride, the liquid modifier may not include the edible oil, and then dried by cold air at 25-35 ° C, preferably 30 ° C, At this time, the processed rice grains can be obtained with a moisture content of about 3 ~ 12%, preferably 3 ~ 5%. The low-moisture rice grains are subjected to hot air expansion, and the hot air outlet temperature is 300 ~ 550 ° C. The temperature is 130 ~ 220 ° C, preferably 150 ~ 200 ° C, the wind speed is 100 ~ 1000m / min, preferably 300m / min, and the swelling time is 5 ~ 15 seconds, preferably 6 ~ 12 seconds. The puffed and dried rice of the present invention can be obtained, and its moisture content is 0.9 ~ 7.7%, preferably 0.9 ~ 3%, its porosity is 45 ~ 90%, preferably 60 ~ 85%, and its false density is 0.2 ~ 0.6 g / mL, preferably 0.2 to 0.4 g / mL. The rice of the present invention may be white rice or colored rice, such as purple rice, brown rice, and the like.

    Examples 1-8 and Comparative Example 1:    

After washing (R103) 1kg of raw white rice (R101) and soaking (R105) for 20 minutes, drain off the excess water (R107), put it in a steam box and cook at 100 ° C (R109) for 20 minutes to obtain about 2 ~ 2.3kg rice . After the rice has cooled slightly, place it on a flat plate in a hot-air drying box, and dry it for the first time (R113) with hot air at 40 ° C. The wind speed is 50m / min, and the time is 20 ~ 30 minutes, until the water content of the rice is about 25 ~ 40. %.

Modifiers were formulated according to the formula in Table 1.

Turn the first dried rice (R115) loose, spray or sprinkle the modifier (R117) in Table 1, and immediately stir to make the surface of the rice grains evenly apply the modifier, and maintain it for 5-10 minutes, so that The modifier is fully absorbed into the surface of the rice. The amount of the modifier (mL modifier / 100 g of first-dried rice) is shown in Table 1.

Take about 1.3 to 1.5 kg of rice with the modifier attached and place it in a dryer for cold air drying (R119) with a wind speed of 50 m / min and a time of 8 to 12 hours. The dried rice is the second dried rice (R121), and its water content is 3 ~ 5%. The surface of the dried rice with the modifier attached under these conditions is intact and free of cracks.

Put the second dried rice (R121) into the expander for hot air expansion (R123), where the amount of rice input is 50 ~ 150g / batch, and the hot air outlet temperature is 300 ~ 550 ℃, preferably 450 ℃ When in contact with materials, the preferred temperature is 150 ~ 200 ° C, the wind speed is 300m / min, and the swelling time is 5 ~ 15 seconds / batch, preferably 6 ~ 12 seconds / batch. The more rice is added, the higher the hot air temperature is; the expansion time is adjusted according to the water content of the rice. The higher the water content, the longer the expansion time.

The properties before rehydration are listed in Table 2.1 and the time required for rehydration is listed in Table 2.2. As can be seen from Table 2.1, the water content of the rice dried from 3 to 12% of the second dried rice (R121) was reduced to 0.9 to 7.7%.

The scorched surface of the expanded dry rice (R125) to be cooled taken out from the hot-air expander was not charred, that is, Examples 1 to 8 and Comparative Example 1.

Pullulan polysaccharide in Table 1 is manufactured by Meihua Biotechnology Group Co., Ltd .; sucrose stearate S-370F is manufactured by Mitsubishi Chemical Foods Co., Ltd .; sucrose stearate S-570 is manufactured by Mitsubishi Chemical Foods Co., Ltd .; Sodium carboxymethyl cellulose is manufactured by CP KELCO; fatty acid glyceride is manufactured by KAO CORPORATION; sodium octenyl succinate starch is manufactured by National Starch and Chemical Co.

The expanded rice after cooling is the instant rice of the present invention (Example 1-8). The properties before rehydration and the quality of the expanded rice are listed in Table 2.1 and the time required for rehydration is listed in Table 2.2.

From Table 2.1, it can be seen that the expanded dry rice of the present invention has a lower false density than that of Comparative Example 1, which ranges from 0.22 to 0.53, which means that the volume after expansion is larger; and in terms of porosity, Example 1 The porosity range of ~ 8 is 60.2% ~ 83.5%, which is higher than that of the control. It is shown that the expanded dry rice of the present invention has a porous structure and can reduce rehydration time. It can also be seen from Table 2.2 that the time required for rehydration of the expanded dry rice of the present invention is shorter than that of Comparative Example 1.

In Examples 1 to 3, less bubbles were generated during the brewing, and the whiteness of the rice was high. Examples 4 to 6 produced more air bubbles during brewing, and the whiteness of the rice was slightly lower than that of Examples 1 to 3. In Examples 7 to 8, the bubbles were medium when brewed, and the whiteness of rice was lower than those of Examples 1 to 3. The aforementioned whiteness (WI) is obtained by measuring the L value, a value, and b value according to a spectrophotometric method, and then calculating the following formula:

The expanded dry rice of Examples 1-8 and Comparative Example 1 were rehydrated for 3 minutes, and then the hardness and viscosity were measured with a texture analyzer (TA-XT2). The measured hardnesses are listed in Table 3. The hardness of Example 2 is similar to that of white rice, the taste is less sticky, and the rice grains are easier to be cut off, while the hardness of Examples 1, 3, 4, and 5 is higher; in addition, the appearance of the rice of Examples 1 to 8 is relatively contrasted Example 1 is uniform.

The false density of the expanded dry rice prepared according to Example 4 is shown in Table 2.1, and the range is 0.22g / mL, but the false density before the hot air expansion in the expander is 0.63 ~ 0.67g / mL, The false density of the white rice raw material used is 0.80 to 0.84 g / mL. Furthermore, the expanded dry rice prepared according to Example 4 has a whiteness of 76.48. The result is close to the whiteness of the white rice raw material used. The whiteness of the dried rice is 72.19, and the second dried rice is expanded in a hot-air expander. The front whiteness is only 63.91.

FIG. 2 shows a scanning electron microscope (SEM) photograph of the expanded dry rice (R125) (A) prepared according to Example 4 and its surface before the expansion (R121) (B). 35X magnification. 3 shows a scanning electron microscope (SEM) photograph of the expanded dry rice (R125) (A) and its cross section before (R121) (B) prepared in Example 4, 35X magnification. It can be seen from FIG. 2 that the dry rice (R121) (B) before bulging has a smoother surface and fewer channels than the bulging dry rice (R125) (A); and the bulging dry rice (R125) ( The surface of A) has many channels, and liquid can enter smoothly when rehydrating. It can be seen from FIG. 3 that the internal structure of the dried rice (R121) (B) before the expansion is relatively solid compared to that of the dried rice (R125) (A); and the expansion of the dried rice (R125) (A) of the present invention Rough surface and porous structure inside. The SEM photographs of FIGS. 2 and 3 show that the expanded dry rice (R125) prepared by the method of the present invention has a structure in which liquid can enter smoothly and rehydration is easy.

Claims (19)

    A method for preparing bulging dry rice, which comprises drying the cooked rice for the first time to a moisture content of 25-40% by weight; stirring and mixing the first dried rice with a liquid modifier to make the surface of the rice coated The liquid modifier is applied; the rice coated with the liquid modifier is dried a second time to a moisture content of 3-12% by weight; the second dried rice is subjected to hot air expansion and obtained after cooling. Bulky dry rice with a water content of 0.9-2.9% by weight, wherein 2.5-20 mL of the liquid modifier is added per 100 grams of the first dried rice, and the liquid modifier contains 0.5- 5 grams of polysaccharide; 0.5-10 grams of emulsifier; 1-5 grams of edible oil; and the balance of water, wherein when the emulsifier is a fatty acid glyceride, the liquid modifier may not include the edible oil.         The method of claim 1, wherein the polysaccharide is a plant polysaccharide.         The method of claim 2, wherein the polysaccharide is pullulan.         The method of claim 2, wherein the polysaccharide is carboxymethyl cellulose-sodium.         The method of claim 1, wherein the polysaccharide is modified starch.         The method according to any one of claims 1 to 5, wherein the emulsifier is an emulsifier having an HLB value of 3-6.         The method according to claim 6, wherein the emulsifier is a sucrose ester, a fatty acid glyceride, a fatty acid sorbate, or a fatty acid propylene glycol ester.         The method of claim 7, wherein the emulsifier is a sucrose ester.         The method of claim 7, wherein the emulsifier is a fatty acid glyceride.         The method of claim 8, wherein the edible oil is soybean oil.         The method of claim 6, wherein 5-10 mL of the liquid modifier is added relative to every 100 grams of the first dried rice.         The method of claim 6, wherein the first drying is performed with hot air at about 40 ° C.         The method of claim 6, wherein the second drying is performed with unheated air or cold air.         The method of claim 6, wherein the hot air expansion is performed with hot air at an outlet temperature of 300-550 ° C, and the temperature of the hot air when it contacts the second dried rice is 150-200 ° C.         The method as claimed in item 14, wherein the hot air eruption is performed for a period of 6-12 seconds.         An expanded dry rice with a pseudo-density of 0.2-0.6 g / mL and a porosity of 45-90%.         Bulky dry rice as claimed in item 16, which has a whiteness of 75-80.         For example, the expanded dry rice of claim 16 has a plurality of channels on its surface and a porous structure inside.         For example, the expanded dry rice of claim 16 has a moisture content of 0.9 to 7.7%.