Method for preparing rice bread by using south japonica rice as raw material

Abstract

The invention discloses a method for preparing rice bread by using southern japonica rice as a raw material, which comprises the following steps of: crushing and sieving the southern japonica rice as the raw material, mixing polished round-grained rice powder and hydroxypropyl methyl cellulose (HPMC), co-extruding to obtain co-extruded powder, and mixing the polished round-grained rice powder and the co-extruded powder according to a certain mass ratio to prepare a rice bread product. The defect that the rice bread is difficult to form a stable structure due to lack of gluten (namely wheat gluten protein) is overcome, pores of the obtained rice bread product are uniform and compact, the texture and taste of the rice bread are improved, and the rice bread with high specific volume and good quality can be prepared. Meanwhile, the method is quick and efficient in process, suitable for mass production, also suitable for people with autoimmune diseases caused by food allergy, celiac disease, gluten sensitivity and the like, and has practical value.

Description

Technical Field

[0001] The invention belongs to the technical field of food processing, relates to the production field of gluten-free food, and specifically relates to a method for preparing rice bread by using southern gluten series rice as a raw material. Background Art

[0002] Rice bread is a gluten-free baked product with a unique taste and complete nutrition. Rice bread is easy to digest and absorb, and is effectively suitable for people with autoimmune diseases such as food allergies, celiac disease and gluten sensitivity. Therefore, in the context of the increasing attention paid to healthy eating, rice bread is gradually attracting the attention of consumers, and the market is showing a trend of sustained growth. However, due to the lack of gluten (i.e., wheat gluten protein) in rice, it is difficult for the prepared rice bread to form a viscoelastic network structure, and the product is difficult to be fluffy, and the specific volume and texture of the bread are seriously affected.

[0003] In recent years, the production formula and production process of rice bread are becoming a research hotspot. "Rice Bread Production and Sensory Quality Research" published in "Food Science and Technology" in 2015 prepared rice bread with rice flour, wheat flour and gluten (i.e. gluten protein extracted from wheat flour) as the basic raw materials. However, its rice bread formula contains bread flour and gluten, which is not suitable for people with gluten sensitivity. "A Rice Bread and Its Preparation Method" with patent publication number CN105901061A prepared rice bread with high-gluten flour and rice flour as the basic raw materials. The above studies all used wheat flour in the formula. Almost all rice bread premixes on the market have wheat flour added. However, there are still very few breads made with pure rice flour. Therefore, it is more valuable to prepare rice bread using only rice as the basic raw material.

[0004] Other studies have found that the amylose content in rice has an important influence on the quality of rice bread. When studying pure rice flour bread, researcher Aoki published a paper titled "Crucial role of amylose in the rising of gluten-and additive-free rice bread" in the Journal of Cereal Science. The results showed that amylose played an important role in the production of rice bread. Rice with an amylose content of up to 22.3% can produce rice bread with high specific volume and stable structure, while rice with an amylose content of 9.6% has a low specific volume and poor texture. Similarly, the paper "Research Progress in Gluten-Free Rice Bread Processing Technology" published in the Journal of the Chinese Cereals and Oils Association in 2022 also demonstrated this point. Therefore, the rice bread premixes currently on the market are all made from indica rice with a high amylose content.

[0005] The Nanjing rice series has a rich aroma and a soft and sticky taste. It is a high-end high-quality rice that is deeply loved by consumers and is also the "most delicious rice in Jiangsu." Researcher Zhu Dawei published "Analysis of the Differences in Physical and Chemical Properties and Taste Quality of China's High Taste Northern Japonica Rice and Southern Semi-Glutinous Japonica Rice Varieties" in "Chinese Agricultural Science" and reported that the taste value of Nanjing rice is over 80 points, which is a high-quality rice. However, there are very few rice products made from Nanjing rice series, and rice bread products made from it have not yet been seen. This is because the content of amylose in Nanjing rice series is very low. The papers "Analysis of the Quality of Japonica Rice in Jiangsu Province and Study on Its Starch Properties" and "Physical and Chemical Properties of Japonica Rice in Jiangsu and Northeast China and Sequence Analysis of Wx and OsSSIIa Genes" reported that the amylose content of Nanjing 2728 was 5.59%, the amylose content of Nanjing 5055 was 5.89%, and the amylose content of Nanjing 46 was 8.49%. Therefore, the use of Nanjing rice series to prepare rice bread can expand the industrial application of Nanjing rice and provide more raw material options for the preparation of rice bread. However, Nanjing rice lacks gluten protein and has a low amylose content, so it is impossible to prepare rice bread with high specific volume and good quality. Therefore, it is also urgent to process it and further prepare it into high-quality rice bread. Summary of the invention

[0006] Purpose of the invention: The technical problem to be solved by the present invention is to provide a method for preparing high-specific volume and good-quality rice bread using Nanjing series rice as raw material.

[0007] Technical solution: In order to solve the above technical problems, the present invention provides a method for preparing rice bread using southern japonica rice as raw material, comprising the following steps: mixing japonica rice flour with HPMC and co-extruding them to obtain co-extruded powder, then mixing the japonica rice flour with the co-extruded powder to obtain mixed powder, and then preparing rice bread products according to conventional methods in the baking industry.

[0008] The co-extrusion conditions are as follows: mixing polished rice flour and HPMC and adjusting the water content to 12-15%, and preparing the co-extrusion powder through an extrusion process.

[0009] Wherein, based on the total mass of the polished rice flour, the content of the HPMC is 20% to 36%.

[0010] Wherein, the mass ratio of the polished round-grained rice flour to the co-extruded powder is 4:1 to 8:1.

[0011] The method specifically comprises the following steps:

[0012] 1) grinding and sieving the southern polished rice to obtain polished rice flour;

[0013] 2) Based on the total mass of the polished rice flour, the polished rice flour and HPMC are mixed and the water content is adjusted to 12-15%, and a co-extruded powder is prepared by an extrusion process;

[0014] 3) mixing the polished rice flour and the co-extruded powder to obtain a mixed powder;

[0015] 4) The mixed flour is used to prepare rice bread products according to conventional methods in the baking industry.

[0016] Wherein, the polished round-grained rice flour in step 1) is passed through a 100-mesh sieve.

[0017] The present invention also includes a rice bread product prepared by the method.

[0018] The method of the invention can be used for preparing fermented rice products by taking rice with low content of amylose as raw material.

[0019] The method of the present invention includes but is not limited to preparing rice bread or rice cake, and other similar foods are within the protection scope of the present invention.

[0020] Beneficial effects: Compared with the prior art, the present invention has the following advantages: the preparation method of the present invention improves the defect that rice bread is difficult to form a stable structure due to the lack of gluten (i.e., wheat gluten protein), the pores of the obtained rice bread product are uniform and dense, the texture and taste of the rice bread are improved, and high specific volume and good quality rice bread can be prepared. At the same time, the method is fast and efficient, suitable for large-scale rapid production, and its formula does not contain additives such as exogenous proteins and enzyme preparations, low cost, and no protein allergens are added, and no gluten protein is added, which is suitable for people with autoimmune diseases such as food allergies, celiac disease and gluten sensitivity, and has practical value. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 is the rheological properties diagram;

[0022] Figure 2 This is a cross-sectional diagram and internal structure diagram of rice bread. DETAILED DESCRIPTION

[0023] The technical solution of the present invention is further described below in conjunction with the accompanying drawings.

[0024] Example 1 Preparation of rice bread using rice of the Nanjing series as raw material

[0025] 1. Buy 46 Nanjing rice in the market, grind it into japonica rice flour, and pass it through a 100-mesh sieve;

[0026] 2. Based on the total mass of polished rice flour, polished rice flour and 20% hydroxypropyl methylcellulose (HPMC) were mixed and the total water content was adjusted to 13%, and a co-extruded powder was prepared by an extrusion process;

[0027] 3. Mixing the polished rice flour and the co-extruded powder in a ratio of 4:1 to prepare a mixed powder;

[0028] 4. Stir and evenly mix 100 parts of the above-mentioned mixed powder, 1.5 parts of salt, 20 parts of white sugar, 5 parts of butter, 2 parts of Angel yeast purchased from the market and 90 parts of drinking water, and shape and ferment the glutinous rice paste at a temperature of 35°C and a humidity of 85°C for 1 hour. Finally, bake the fermented glutinous rice paste at 150°C for upper heat and 180°C for lower heat for 30 minutes to obtain a rice bread product.

[0029] Example 2

[0030] 1. Crush Nanjing 46 rice to obtain rice flour, and pass through a 100-mesh sieve;

[0031] 2. Based on the total mass of polished rice flour, polished rice flour and 28% HPMC were mixed and the water content was adjusted to 13%, and co-extruded powder was prepared by extrusion process;

[0032] 3. Mixing the polished rice flour and the co-extruded powder in a ratio of 6:1 to prepare a mixed powder;

[0033] 4. Stir and evenly mix 100 parts of the above-mentioned mixed powder, 1.5 parts of salt, 20 parts of white sugar, 5 parts of butter, 2 parts of Angel yeast purchased from the market and 90 parts of drinking water, and shape and ferment the glutinous rice paste at a temperature of 35°C and a humidity of 85°C for 1 hour. Finally, bake the fermented glutinous rice paste at 150°C for upper heat and 180°C for lower heat for 30 minutes to obtain a rice bread product.

[0034] Example 3

[0035] 1. Grind Nanjing 46 rice to obtain japonica rice flour, and pass it through a 100-mesh sieve;

[0036] 2. Based on the total mass of polished rice flour, polished rice flour and 36% HPMC were mixed and the water content was adjusted to 13%, and co-extruded powder was prepared by extrusion process;

[0037] 3. Mixing the polished rice flour and the co-extruded powder in a ratio of 8:1 to prepare a mixed powder;

[0038] 4. Stir and evenly mix 100 parts of the above-mentioned mixed powder, 1.5 parts of salt, 20 parts of white sugar, 5 parts of butter, 2 parts of Angel yeast purchased from the market and 90 parts of drinking water, and shape and ferment the glutinous rice paste at a temperature of 35°C and a humidity of 85°C for 1 hour. Finally, bake the fermented glutinous rice paste at 150°C for upper heat and 180°C for lower heat for 30 minutes to obtain a rice bread product.

[0039] Comparative Example 1

[0040] 1. Grind Nanjing 46 rice to obtain japonica rice flour, and pass it through a 100-mesh sieve;

[0041] 2. Stir and evenly mix 100 parts of the above-mentioned rice flour, 1.5 parts of salt, 20 parts of white sugar, 5 parts of butter, 2 parts of Angel yeast purchased from the market and 90 parts of drinking water, shape and ferment the rice paste at a temperature of 35°C and a humidity of 85°C for 1 hour, finally, bake the fermented rice paste at 150°C for upper heat and 180°C for lower heat for 30 minutes, and obtain a rice bread product after baking.

[0042] Comparative Example 2

[0043] 1. Grind Nanjing 46 rice to obtain japonica rice flour, and pass it through a 100-mesh sieve;

[0044] 2. Based on the total mass of polished rice flour, polished rice flour and 4% HPMC were mixed to prepare mixed powder;

[0045] 3. Stir and evenly mix 100 parts of the above-mentioned mixed powder, 1.5 parts of salt, 20 parts of white sugar, 5 parts of butter, 2 parts of Angel yeast purchased from the market and 90 parts of drinking water, and shape and ferment the glutinous rice paste at a temperature of 35°C and a humidity of 85°C for 1 hour. Finally, bake the fermented glutinous rice paste at 150°C for upper heat and 180°C for lower heat for 30 minutes to obtain a rice bread product.

[0046] Comparative Example 3

[0047] 1. Grind Nanjing 46 rice to obtain japonica rice flour, and pass it through a 100-mesh sieve;

[0048] 2. Based on the total mass of polished rice flour, the water content of polished rice flour is adjusted to 13%, and extruded powder is prepared by extrusion process;

[0049] 3. Based on the total mass of polished rice flour, polished rice flour and extruded powder are mixed in a ratio of 6:1 to prepare mixed powder;

[0050] 4. Stir and evenly mix 100 parts of the above-mentioned mixed powder, 1.5 parts of salt, 20 parts of white sugar, 5 parts of butter, 2 parts of Angel yeast purchased from the market and 90 parts of drinking water, and shape and ferment the glutinous rice paste at a temperature of 35°C and a humidity of 85°C for 1 hour. Finally, bake the fermented glutinous rice paste at 150°C for upper heat and 180°C for lower heat for 30 minutes to obtain a rice bread product.

[0051] Comparative Example 4

[0052] 1. Grind Nanjing 46 rice to obtain japonica rice flour, and pass it through a 100-mesh sieve;

[0053] 2. Based on the total mass of polished rice flour, the water content of polished rice flour is adjusted to 13%, and extruded powder is prepared by extrusion process;

[0054] 3. Mix the polished rice flour and extruded powder in a ratio of 6:1, and then add 4% HPMC based on the total mass of the mixed rice flour;

[0055] 4. Stir and evenly mix 100 parts of the above-mentioned mixed powder, 1.5 parts of salt, 20 parts of white sugar, 5 parts of butter, 2 parts of Angel yeast purchased from the market and 90 parts of drinking water, and shape and ferment the glutinous rice paste at a temperature of 35°C and a humidity of 85°C for 1 hour. Finally, bake the fermented glutinous rice paste at 150°C for upper heat and 180°C for lower heat for 30 minutes to obtain a rice bread product.

[0056] The following series of indicators are used to evaluate and compare the quality of the products in each embodiment and comparative example.

[0057] Indicator 1: Hydration capacity

[0058] Water absorption index (WAI) and water solubility index (WS) represent the hydration capacity of rice flour. Rice flour has a strong hydration capacity and is easy to prepare high-quality rice bread.

[0059] Experimental method: First, 2 g of japonica rice flour was dispersed in 40 mL of distilled water and stirred in a water bath at 30 ° C for 30 min. Then, the suspension was centrifuged at 4500 r / min for 30 min. The wet precipitate was weighed and the supernatant was dried at 105 ° C until a constant mass was obtained. Wherein, WAI = m1 / m; WS (%) = m2 / m × 100%, where: m1 represents the weight of the wet precipitate, g; m2 represents the weight of the dry solid supernatant, g; m represents the weight of the dry japonica rice flour, g.

[0060] Indicator 2: Fermentation capacity

[0061] The two important factors that affect the fermentation of rice bread are the gas production of yeast and the gas retention of rice paste. High gas production and good gas retention make it easier to prepare high-quality rice bread.

[0062] Experimental method: The fermentation capacity of japonica rice paste is determined by placing 5g of rice paste with yeast added into a square tube, sealing both ends of the square tube, and observing the fermentation capacity of the japonica rice paste. The fermentation length (cm) of the japonica rice paste is measured before and after fermentation for 30 minutes.

[0063] Indicator 3: Rheological properties

[0064] Rheological properties are mainly evaluated by elastic modulus (G') and viscous modulus (G"), etc. G' refers to the elasticity of rice paste, and G" refers to the viscosity of rice paste. Changes in hydration capacity in rice flour will affect its rheological properties. Generally speaking, rice flour with high viscoelasticity can retain gas during mixing and stirring into rice paste, thereby making the rheological properties of rice paste better and making it easier to prepare rice bread with high specific volume.

[0065] Experimental method: The rheological properties of rice paste samples were measured using a rheometer.

[0066] Indicator 4: Specific volume of rice bread

[0067] The specific volume of rice bread is one of the main parameters to describe the quality of rice bread. The larger the specific volume, the better the fluffiness of the rice bread.

[0068] Experimental method: The specific volume of rice bread was determined by the rapeseed displacement method. The mass of rice bread was measured by a balance, the volume of rice bread was determined by the rapeseed displacement method, and the specific volume of rice bread was calculated by dividing the volume of rice bread (mL) by the weight of rice bread (g).

[0069] Indicator 5: Hardness and resilience of rice bread

[0070] The hardness of rice bread is the maximum force value when the probe is compressed for the first time. The smaller the hardness, the better the fluffiness of rice bread. Resilience is an indicator that describes the elasticity of rice bread. The better the resilience, the better the taste of rice bread during chewing, and the easier it is for consumers to accept rice bread.

[0071] Experimental method: The texture was determined using a texture analyzer.

[0072] Indicator 6: Sensory evaluation of rice bread

[0073] Sensory evaluation is the most direct and effective method to judge the quality of rice bread. The higher the sensory evaluation score, the better the quality of the rice bread.

[0074] Experimental method: The sensory evaluation of rice bread was conducted by 6 tasters on the shape, aroma, color, organizational structure and taste of each group of rice bread. The scoring standard was based on a 9-point system (1-4 represents poor, 5 represents medium, 6-9 represents good, and the higher the score, the better the sensory quality of the bread). The scores of each group of samples were then statistically analyzed to obtain the final results.

[0075] The effects of each embodiment and comparative example are as follows:

[0076] 1. Hydration capacity

[0077] As shown in Table 1, Comparative Example 1 is the original glutinous rice flour bread, which has not been extruded and has no HPMC added, and its WAI and WS are the smallest. Comparative Example 2 is the bread with HPMC added to glutinous rice flour, and Comparative Example 3 is the mixed flour raw material bread, and its WAI and WS increase, but are significantly lower than those of the examples. Comparative Example 4 is the one in which HPMC is added to the mixed flour, and its WAI value is higher than that of the examples, but its WS value is lower than that of the examples, but there is no statistical difference.

[0078] Table 1 Hydration capacity

[0079] sample WAI(g / g) WS(%) Comparative Example 1 <![CDATA[3.13±0.02 c ]]> <![CDATA[3.67±0.67 b ]]> Comparative Example 2 <![CDATA[3.38±0.07 bc ]]> <![CDATA[10.00±0.58 b ]]> Comparative Example 3 <![CDATA[3.91±0.14 ab ]]> <![CDATA[10.00±2.08 b ]]> Comparative Example 4 <![CDATA[4.32±0.11 a ]]> <![CDATA[17.67±2.03 a ]]> Example 1 <![CDATA[4.04±0.28 a ]]> <![CDATA[20.01±2.64 a ]]> Example 2 <![CDATA[4.09±0.09 a ]]> <![CDATA[20.00±2.65 a ]]> Example 3 <![CDATA[4.06±0.28 a ]]> <![CDATA[20.07±2.61 a ]]>

[0080] Note: Different lowercase letters in the same column indicate significant differences (P<0.05)

[0081] 2. Fermentation capacity

[0082] It can be seen from Table 2 that the initial states of each group are the same, but after 30 minutes of fermentation, the gas production and gas retention of the embodiment group are significantly better than those of the comparative example group. After 30 minutes of fermentation of the japonica rice paste, the fermentation capacity of comparative example 1 is not obvious; comparative examples 2 to 4 have a certain fermentation capacity, but are significantly lower than the embodiment group; the fermentation capacity of the three groups of embodiments is good. Among them, the fermentation capacity of embodiment 2 is the best, and the fermentation length is increased by 2.98 cm. This shows that the method of the embodiment can make the japonica rice paste produce more gas and have better gas retention.

[0083] Table 2 Fermentation capacity

[0084] sample Fermentation 0min / (cm) Fermentation 30min / (cm) Comparative Example 1 <![CDATA[2.81±0.03 a ]]> <![CDATA[3.35±0.03 d <!-- 5 -->]]> Comparative Example 2 <![CDATA[2.82±0.04 a ]]> <![CDATA[4.33±0.08 c ]]> Comparative Example 3 <![CDATA[2.80±0.06 a ]]> <![CDATA[4.35±0.04 c ]]> Comparative Example 4 <![CDATA[2.80±0.06 a ]]> <![CDATA[4.45±0.02 c ]]> Example 1 <![CDATA[2.83±0.04 a ]]> <![CDATA[5.49±0.04 b ]]> Example 2 <![CDATA[2.86±0.02 a ]]> <![CDATA[5.84±0.07 a ]]> Example 3 <![CDATA[2.82±0.05 a ]]> <![CDATA[5.69±0.05 a ]]>

[0085] Note: Different lowercase letters in the same column indicate significant differences (P<0.05)

[0086] 3. Rheological properties

[0087] Depend on Figure 1 It can be seen that G' and G" of all groups increase with the continuous increase of frequency, and G' of each group is greater than G", which means that the elasticity of each group of polished rice paste is greater than the viscosity. The G' and G" of Comparative Example 1 are smaller, and the G' and G" of Examples 1 to 3 are larger, among which the G' and G" of Example 2 are significantly increased, and the change trends of G' and G" of Comparative Examples 2 to 4 are between Comparative Example 1 and Examples 1 to 3. It means that the rheological properties of polished rice paste of Comparative Examples 2 to 4 are better than those of Comparative Example 1, but not as good as those of the three groups of Examples. Therefore, by adopting the method of the embodiment, the polished rice paste has better viscoelasticity and better rheological properties, and the prepared rice bread has a higher specific volume.

[0088] 4. Quality evaluation of rice bread

[0089] The quality of rice bread is mainly evaluated from the aspects of specific volume, hardness, resilience and sensory evaluation of the product. As shown in Table 3, the specific volume of the rice bread prepared according to the method of the embodiment of the present invention is significantly higher than that of the comparative example group, and the hardness is significantly lower than that of the comparative example group, indicating that the rice bread of the embodiment group has a good fluffy effect and a soft taste. Figure 2 ), which together reflect that the bread product of the embodiment group forms a fluffy, uniform and dense network structure.

[0090] Table 3 Quality evaluation of rice bread

[0091]

[0092]

[0093] Note: Different lowercase letters in the same column indicate significant differences (P<0.05)

[0094] Therefore, the quality of the rice bread prepared by the method of the embodiment is better, and the quality of Example 2 is the best.

Claims

1. A method for preparing rice bread using rice of the Nanjing series as raw material, characterized in that: The following steps are involved: The polished rice flour and HPMC are mixed and co-extruded to obtain co-extruded powder, and then the polished rice flour and the co-extruded powder are mixed to obtain mixed powder, and then the rice bread product is prepared according to the conventional method of the baking industry.

2. The method for preparing rice bread using rice of the Nanjing series as raw material according to claim 1, characterized in that: The co-extrusion conditions are as follows: mixing polished rice flour and HPMC and adjusting the water content to 12-15%, and preparing co-extruded powder by extrusion process.

3. The method for preparing rice bread using rice of the Nanjing series as raw material according to claim 2, characterized in that: Based on the total mass of the polished rice flour, the content of HPMC is 20% to 36%.

4. The method for preparing rice bread using rice of the Nanjing series as raw material according to claim 1, characterized in that: The mass ratio of the polished round-grained rice flour to the co-extruded flour is 4:1-8:

1.

5. A method for preparing rice bread using rice of the Nanjing series as raw material according to any one of claims 1 to 5, characterized in that: The specific steps include: 1) Take the Nanjing rice, grind it and sieve it to obtain the japonica rice flour; 2) Based on the total mass of japonica rice flour, japonica rice flour and HPMC were mixed and the water content was adjusted to 12-15%, and a co-extruded powder was prepared by extrusion process; 3) mixing the polished rice flour and the co-extruded powder to obtain a mixed powder; 4) The mixed flour is used to prepare rice bread products according to conventional methods in the baking industry.

6. The method for preparing rice bread using rice of the Nanjing series as raw material according to claim 5, characterized in that: The japonica rice flour in step 1) is passed through a 100-mesh sieve.

7. The rice bread product prepared by the method according to any one of claims 1 to 6.

Images