Preparation method of low-sugar fermented red date pulp and low-glycemic red date cake

Abstract

The invention relates to the technical field of food processing, in particular to a preparation method of low-sugar fermented red jujube pulp and low-glycemic red jujube cakes. According to the method disclosed by the invention, the fructosyl transferase and the glucose oxidase are used for carrying out double-stage enzymolysis on the red date primary pulp, so that the conversion rate of sucrose is increased, the content of a byproduct glucose in the sucrose conversion process is reduced, and then the lactobacillus rhamnosus and the lactobacillus plantarum are used for fermenting the red date pulp, so that the eGI value of the red date primary pulp can be reduced through the method.

Description

Technical Field

[0001] The invention relates to the technical field of food processing, and in particular to a preparation method of low-sugar fermented red date pulp and low-glycemic red date cake. Background Art

[0002] Red dates, also known as jujubes, dried dates, etc., are the mature fruit of the genus Ziziphus of the Rhamnaceae family. They have a history of more than 8,000 years in China. Red dates contain a variety of biologically active ingredients, such as polysaccharides, polyphenols, ascorbic acid, triterpene acids, cyclic adenosine monophosphate, etc.

[0003] Modern food and medical research shows that red dates have a variety of health benefits, such as protecting the liver, anti-oxidation, lowering blood sugar and anti-tumor. It is widely used to nourish the stomach and spleen, nourish blood and promote body fluid, and strengthen physical fitness. China is the world's largest producer of red dates. In addition to fresh consumption, red dates are also processed into a variety of products such as dried fruits, candied dates, date slices, date juice, date wine and date vinegar. At present, the research focus is on further processing red dates to better retain their nutrients, improve flavor and quality, and develop their health and pharmacological functions. The glycemic index (GI) refers to the ratio of the blood sugar-raising effect of a certain food to the blood sugar-raising effect of a standard food (usually glucose), which represents how much blood sugar response a certain amount of a certain food will cause in the human body. Traditional red date cakes are relatively sweet and greasy, which does not meet the health requirements of today's human beings. It is extremely unfriendly to people with high blood sugar and people who want to lose weight. This is because the existing red date pulp used to prepare red date cakes has a high glycemic index. In order to meet health requirements, it is necessary to provide a method for preparing low-sugar red date pulp. Summary of the invention

[0004] In order to solve the above problems, the present invention provides a method for preparing low-sugar fermented red date pulp and a method for preparing low-glycemic red date cake.

[0005] A method for preparing low-sugar fermented red date pulp comprises washing, removing pits, rehydrating and softening, and beating to obtain red date pulp, and further comprises the following steps: The first enzymatic hydrolysis: add 15U~25U fructosyltransferase to each gram of red date pulp for the first enzymatic hydrolysis, and inactivate the enzyme after the first enzymatic hydrolysis to obtain the first enzymatic hydrolysis product; The second enzymatic hydrolysis: adding 60U-70U glucose oxidase to each gram of the first enzymatic hydrolysis product for a second enzymatic hydrolysis, and inactivating the enzyme after the second enzymatic hydrolysis to obtain a second enzymatic hydrolysis product; Probiotic fermentation: adding 0.8% to 1% by mass of Lactobacillus plantarum and 0.8% to 1% by mass of Lactobacillus rhamnosus to each gram of the second enzymatic hydrolysis product, and obtaining the low-sugar fermented red date pulp after fermentation.

[0006] Preferably, the temperature of the first enzymatic hydrolysis is 45°C to 55°C.

[0007] Preferably, the first enzymatic hydrolysis time is 3.5h~4.5h.

[0008] Preferably, the temperature of the second enzymatic hydrolysis is 30°C to 35°C.

[0009] Preferably, the second enzymatic hydrolysis time is 2h~2.5h.

[0010] Preferably, the rehydration and softening is specifically to add water to the pitted red dates at a solid-liquid ratio of 1:2-2.5 and soak for 2h-3h.

[0011] A method for preparing a low-glycemic red date cake comprises the following steps: Taking eggs, separating them to obtain egg white and egg yolk, adding L-arabinose to the egg white, and beating the egg white to obtain whipped egg white; Add the low-sugar fermented red date paste and mixed powder described in claim 1 to the egg yolk, and mix well to obtain a batter; the mixed powder consists of 60% to 70% by mass of highland barley flour, 10% to 15% by mass of black whole wheat flour, 5% to 8% by mass of inulin, 5% to 8% by mass of psyllium husk powder, 5% to 14% by mass of oat bran powder, and 0.1% to 0.5% by mass of konjac flour; Take 1 / 3 of the beaten egg white and mix it with the batter to obtain paste 1, and mix paste 1 with the remaining 2 / 3 of the beaten egg white to obtain paste 2; The obtained paste is baked at 140° C. to 150° C. for 70 min to 80 min to obtain the low-glycemic red date cake.

[0012] Preferably, the mass ratio of the low-sugar fermented red date pulp to the mixed powder is 2-2.5:1, and the mass ratio of the low-sugar fermented red date pulp to the L-arabinose is 20-25:1; and the number of eggs is 1 / 15-20 of the weight of the cereal flour.

[0013] Preferably, bake at 140°C to 150°C for 70min to 80min.

[0014] Compared with the prior art, the present invention is beneficial in that: The invention performs low-sugar treatment on red date pulp, uses double-stage enzymolysis to promote the conversion of sucrose into oligosaccharides, reduces the content of byproduct glucose, and further reduces the sucrose content by fermentation. Specifically, fructosyltransferase and glucose oxidase are used to perform double-stage enzymolysis on the red date pulp, so as to improve the conversion rate of sucrose and reduce the content of byproduct glucose in the process of sucrose conversion. The purpose of enzymolysis is to convert sucrose into oligofructose. The enzyme widely used in food with this function is fructosyltransferase, and other enzymes do not have this function. Glucose oxidase can degrade the byproduct glucose. Then, rhamnosus lactobacillus and plantarum lactobacillus are used to ferment the date pulp, so as to improve the nutritional value of food. The GI value of the red date pulp can be reduced by the method, and the blood sugar reduction effect when using rhamnosus lactobacillus, plantarum lactobacillus and other lactobacillus for fermentation, or using a single lactobacillus for fermentation is significantly lower than the blood sugar reduction effect of rhamnosus lactobacillus and plantarum lactobacillus.

[0015] In the preparation of the red date cake, highland barley flour, black whole wheat flour, inulin, oat bran powder, psyllium husk powder, and konjac flour are used, and L-arabinose is used as a seasoning. Although it has a sweet taste, it will not make people fat. No edible oil and baking powder are added in the preparation process. Compared with the traditional red date cake, the prepared red date cake has the characteristics of low GI, zero oil and low sugar, which is in line with the modern health concept.

[0016] Compared with traditional red date cakes, the red date cakes prepared by the present invention have lower sucrose content, more fragrant flavor and lower glycemic index, and can help consumers increase their sense of fullness. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 The figure is a bar graph of the sucrose content of the red date puree at each stage in Example 1, Example 2 and Example 3. In the figure, different letters in each group of examples represent significant differences.

[0018] Figure 2 The figure is a bar graph of the total sugar content of the red date puree at each stage of Example 1, Example 2 and Example 3. In the figure, different letters in each group of examples represent significant differences.

[0019] Figure 3 The figure is a bar graph of the glucose content of the red date puree at each stage in Example 1, Example 2 and Example 3. In the figure, different letters in each group of examples represent significant differences.

[0020] Figure 4 It is a bar graph of the eGI values ​​of the red date cakes of Example 4, Example 5, Comparative Example 1, Comparative Example 2, Comparative Example 3, and Comparative Example 4. In the graph, different letters represent significant differences.

[0021] Figure 5These are the results of glucose content determination of the red date purees in Comparative Examples 5 to 8 after different fermentation treatments. In the figure, * represents P<0.05, and ** represents P<0.01.

[0022] Figure 6 These are the results of total sugar content determination of the red date purees in Comparative Examples 5 to 8 after different fermentation treatments. In the figure, * represents P<0.05. DETAILED DESCRIPTION

[0023] The specific embodiments of the present invention are described in detail below, but it should be understood that the protection scope of the present invention is not limited by the specific embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work belong to the protection scope of the present invention. The experimental methods described in the embodiments of the present invention are conventional methods unless otherwise specified.

[0024] The present invention adopts an in vitro simulation method to simulate the physical and chemical environment of human digestive activities, and can measure the estimated glycemic index (eGI) value of the sample. In the in vitro experiment, by simulating the digestive environment of the sample in the human gastrointestinal tract, the eGI value of the sample is finally calculated. The method is simple to operate, has a short detection cycle, low cost, and can carry out multiple parallel experimental groups. It can be used as a raw material and formula screening in the process of developing low GI foods.

[0025] The invention performs low-sugar treatment on red date pulp, uses double-stage enzymolysis to promote the conversion of sucrose into oligosaccharides, reduces the content of byproduct glucose, and further reduces the sucrose content through fermentation. Specifically, fructosyltransferase and glucose oxidase are used to perform double-stage enzymolysis on the red date pulp, so as to improve the conversion rate of sucrose and reduce the content of byproduct glucose in the process of sucrose conversion. Then, Lactobacillus rhamnosus and Lactobacillus plantarum are used to ferment the jujube pulp to improve the nutritional value. The GI value of the red date pulp can be reduced by the method.

[0026] In the preparation of red date cake, traditional wheat flour has a higher glycemic index and is relatively simple in nutritional value compared with whole grain flour. The present invention uses highland barley flour, black whole wheat flour, inulin, oat bran powder, psyllium husk powder, and konjac flour, and uses L-arabinose as a flavoring agent. Although it has a sweet taste, it will not make people fat. No edible oil and baking powder are added during the preparation process. Compared with traditional red date cake, the prepared red date cake has the characteristics of low GI, zero oil and low sugar, and is in line with modern health concepts.

[0027] The highland barley flour used in the present invention is purchased from Wangu Shimei with a product number of 100022744712; the black whole wheat flour is purchased from Wangu Shimei with a product number of 100006275109; the inulin is purchased from Alande with a product number of 100119929749; the oat bran powder is purchased from Yifang with a product number of 10073895557070; the konjac powder is purified konjac micropowder purchased from Shaanxi Ankang Konjac Biotechnology Co., Ltd., special grade A; the psyllium husk powder is psyllium husk powder purchased from Xi'an Yuankui Biotechnology Co., Ltd., with a specification of 99% and a batch number of YKSW20240314.

[0028] Example 1 A method for preparing low-sugar fermented red date pulp comprises the following steps: (1) Cleaning and pitting: Use bubbling and brushing to remove impurities on the skin of the red dates, drain them, remove the pits from the red dates and weigh them.

[0029] (2) Rehydration and softening: The pitted red dates are rehydrated with a solid-liquid ratio of 1:2 and soaked at room temperature for 2 h to fully soften the red dates and dissolve the soluble solids.

[0030] (3) Beating: Use an ultra-fine grinder to beat the red dates to obtain red date pulp.

[0031] (4) First stage of enzymatic hydrolysis: 15 U of fructosyltransferase was added to each gram of the red date pulp obtained in step (3), and the enzymatic hydrolysis was carried out at a temperature of 45° C. for 4 h. After the reaction, the enzyme activity was inactivated to obtain the first enzymatic hydrolysis product.

[0032] (5) Second stage of enzymatic hydrolysis: add 60 U of glucose oxidase to each gram of the first enzymatic hydrolysis product, and react with oxygen at 30°C for 2 h. After the reaction, inactivate the enzyme to obtain the second enzymatic hydrolysis product.

[0033] (6) Probiotic fermentation: Add 1% by mass of Lactobacillus plantarum and 1% by mass of Lactobacillus rhamnosus to the second enzymatic hydrolysis product, ferment at 35°C for 10 h to obtain low-sugar fermented red date pulp, and store it in a refrigerator at 4°C for 10 h before use.

[0034] Example 2 A method for preparing low-sugar fermented red date pulp comprises the following steps: (1) Cleaning and pitting: Use bubbling and brushing to remove impurities such as loose soil on the surface of the red dates, drain them, remove the pits from the red dates and weigh them.

[0035] (2) Rehydration and softening: The pitted red dates are rehydrated with a solid-liquid ratio of 1:2 and soaked at room temperature for 2 h to fully soften the red dates and dissolve the soluble solids.

[0036] (3) Beating: Use an ultra-fine grinder to beat the red dates to obtain red date pulp.

[0037] (4) First stage of enzymatic hydrolysis: add 20 U of fructosyltransferase to each gram of the red date pulp obtained in step (3), perform enzymatic hydrolysis at 50° C. for 4 h, inactivate the enzyme after the reaction, and obtain the first enzymatic hydrolysis product.

[0038] (5) Second stage of enzymatic hydrolysis: add 65 U of glucose oxidase to each gram of the first enzymatic hydrolysis product, and react with oxygen at 35°C for 2 h. After the reaction, inactivate the enzyme to obtain the second enzymatic hydrolysis product.

[0039] (6) Probiotic fermentation: Add 1% by mass of Lactobacillus plantarum and 1% by mass of Lactobacillus rhamnosus to the second enzymatic hydrolysis product, and ferment at 35°C for 15 h to obtain low-sugar fermented red date pulp, which is then stored in a refrigerator at 4°C for 10 h before use.

[0040] Example 3 A method for preparing low-sugar fermented red date pulp comprises the following steps: (1) Cleaning and pitting: Use bubbling and brushing to remove impurities such as loose soil on the surface of the red dates, drain them, remove the pits from the red dates and weigh them.

[0041] (2) Rehydration and softening: The pitted red dates are rehydrated with a solid-liquid ratio of 1:2 and soaked at room temperature for 2 h to fully soften the red dates and dissolve the soluble solids.

[0042] (3) Beating: Use an ultra-fine grinder to beat the red dates to obtain red date pulp.

[0043] (4) First stage of enzymatic hydrolysis: 25 U of fructosyltransferase was added to each gram of the red date pulp obtained in step (3), and the enzymatic hydrolysis was carried out at a temperature of 55° C. for 4 h. After the reaction, the enzyme activity was inactivated to obtain the first enzymatic hydrolysis product.

[0044] (5) Second stage of enzymatic hydrolysis: add 70 U of glucose oxidase to each gram of the first enzymatic hydrolysis product, and react with oxygen at 35°C for 2 h. After the reaction, inactivate the enzyme to obtain the second enzymatic hydrolysis product.

[0045] (6) Probiotic fermentation: Add 1% by mass of Lactobacillus plantarum and 1% by mass of Lactobacillus rhamnosus to the second enzymatic hydrolysis product, and ferment at 35°C for 15 h to obtain low-sugar fermented red date pulp, which is then stored in a refrigerator at 4°C for 10 h before use.

[0046] Example 4 A method for preparing a low-glycemic red date cake comprises the following steps: (1) Weigh 200 g of the low-sugar fermented red date pulp obtained in Example 1 for later use, and mix 70 g of highland barley flour, 15 g of dark whole wheat flour, 5 g of inulin, 5 g of psyllium husk powder, 3 g of oat bran powder, and 0.5 g of konjac flour to obtain a mixed powder.

[0047] (2) Take 4 eggs, separate the egg whites and egg whites, beat the egg whites into a bowl without water or oil, add 5g of L-arabinose to the egg whites, and beat with a whisk until it is three times the original volume.

[0048] (3) Add the mixed powder and the low-sugar fermented red date paste weighed in step (1) to the egg yolk separated in step (2), and stir evenly to obtain a batter.

[0049] (4) Take 1 / 3 of the whipped egg whites and mix them with the batter to obtain paste 1. Then pour all of paste 1 into the remaining 2 / 3 of the whipped egg whites and stir to obtain paste 2.

[0050] (5) Pour the obtained paste into a baking tray, shake out the bubbles, put the baking tray into the oven, bake at 150℃ for 70 minutes, take it out, cool to room temperature, cut into pieces, and store in bags.

[0051] Example 5 A method for preparing a low-glycemic red date cake comprises the following steps: (1) Weigh 180 g of the low-sugar fermented red date pulp obtained in Example 1 for later use, and mix 60 g of highland barley flour, 10 g of dark whole wheat flour, 8 g of inulin, 8 g of psyllium husk powder, 6 g of oat bran powder, and 0.5 g of konjac flour to obtain a mixed powder.

[0052] (2) Take 4 eggs, separate the egg whites and egg whites, beat the egg whites into a bowl without water or oil, add 4g of L-arabinose to the egg whites, and beat with a whisk until it is three times the original volume.

[0053] (3) Add the mixed powder and the low-sugar fermented red date paste weighed in step (1) to the egg yolk separated in step (2), and stir evenly to obtain a batter.

[0054] (4) Take 1 / 3 of the whipped egg whites and mix them with the batter to obtain paste 1. Then pour all of paste 1 into the remaining 2 / 3 of the whipped egg whites and stir to obtain paste 2.

[0055] (5) Pour the obtained paste into a baking tray, shake out the bubbles, put the baking tray into the oven, bake at 150℃ for 70 minutes, take it out, cool to room temperature, cut into pieces, and store in bags.

[0056] Comparative Example 1 A method for preparing red date cake comprises the following steps: (1) Take 200 g of the low-sugar fermented red date pulp obtained in Example 1 and set aside, and take 100 g of wheat flour.

[0057] (2) Take 4 eggs, separate the egg whites and egg whites, beat the egg whites into a bowl without water or oil, add 5g of white sugar to the egg whites, and stir to get whipped egg whites.

[0058] (3) Add wheat flour, 4 g corn oil and the low-sugar fermented red date paste weighed in step (1) to the egg yolk separated in step (2), and stir evenly to obtain a batter.

[0059] (4) Take 1 / 3 of the whipped egg whites and mix them with the batter to obtain paste 1. Then pour all of paste 1 into the remaining 2 / 3 of the whipped egg whites and stir to obtain paste 2.

[0060] (5) Pour the obtained paste into a baking tray, shake out the bubbles, put the baking tray into the oven, bake at 150℃ for 70 minutes, take it out, cool to room temperature, cut into pieces, and store in bags.

[0061] Comparative Example 2 A method for preparing red date cake comprises the following steps: (1) Weigh 200 g of the low-sugar fermented red date pulp obtained in Example 1 for later use, and mix 70 g of highland barley flour and 30 g of dark whole wheat flour to obtain cereal flour.

[0062] (2) Take 4 eggs, separate the egg whites and egg whites, beat the egg whites into a bowl without water or oil, add 5g of white sugar to the egg whites, and stir to get whipped egg whites.

[0063] (3) Add cereal flour, 5 g corn oil and the low-sugar fermented red date paste weighed in step (1) to the egg yolk separated in step (2), and stir evenly to obtain a batter.

[0064] (4) Take 1 / 3 of the whipped egg whites and mix them with the batter to obtain paste 1. Then pour all of paste 1 into the remaining 2 / 3 of the whipped egg whites and stir to obtain paste 2.

[0065] (5) Pour the obtained paste into a baking tray, shake out the bubbles, put the baking tray into the oven, bake at 150℃ for 70 minutes, take it out, cool to room temperature, cut into pieces, and store in bags.

[0066] Comparative Example 3 A method for preparing red date cake comprises the following steps: (1) Weigh 200 g of the low-sugar fermented red date pulp obtained in Example 1, and mix 70 g of highland barley flour and 30 g of dark whole wheat flour to obtain cereal flour.

[0067] (2) Take 3 eggs, separate the egg whites and egg whites, beat the egg whites into a bowl without water or oil, add 5g of white sugar to the egg whites, and stir to get whipped egg whites.

[0068] (3) Add cereal flour, 4 g corn oil and the low-sugar fermented red date paste weighed in step (1) to the egg yolk separated in step (2), and stir evenly to obtain a batter.

[0069] (4) Take 1 / 3 of the whipped egg whites and mix them with the batter to obtain paste 1. Then pour all of paste 1 into the remaining 2 / 3 of the whipped egg whites and stir to obtain paste 2.

[0070] (5) Pour the obtained paste into a baking tray, shake out the bubbles, put the baking tray into the oven, bake at 150℃ for 70 minutes, take it out, cool to room temperature, cut into pieces, and store in bags.

[0071] Comparative Example 4 A method for preparing a low-glycemic red date cake comprises the following steps: (1) Weigh 200 g of the low-sugar fermented red date pulp obtained in Example 1 for later use, and mix 70 g of highland barley flour and 30 g of dark whole wheat flour to obtain cereal flour.

[0072] (2) Take 4 eggs, separate the egg whites and egg whites, beat the egg whites into a bowl without water or oil, add 5 g of L-arabinose to the egg whites, and stir to obtain whipped egg whites.

[0073] (3) Add cereal flour, 4 g corn oil and the low-sugar fermented red date paste weighed in step (1) to the egg yolk separated in step (2), and stir evenly to obtain a batter.

[0074] (4) Take 1 / 3 of the whipped egg whites and mix them with the batter to obtain paste 1. Then pour all of paste 1 into the remaining 2 / 3 of the whipped egg whites and stir to obtain paste 2.

[0075] (5) Pour the obtained paste into a baking tray, shake out the bubbles, put the baking tray into the oven, bake at 150℃ for 70 minutes, take it out, cool to room temperature, cut into pieces, and store in bags.

[0076] Comparative Example 5 A method for preparing low-sugar fermented red date pulp comprises the following steps: (1) Cleaning and pitting: Use bubbling and brushing to remove impurities such as loose soil on the surface of the red dates, drain them, remove the pits from the red dates and weigh them.

[0077] (2) Rehydration and softening: The pitted red dates are rehydrated with a solid-liquid ratio of 1:2 and soaked at room temperature for 2 h to fully soften the red dates and dissolve the soluble solids.

[0078] (3) Beating: Use an ultra-fine grinder to beat the red dates to obtain red date pulp.

[0079] (4) Probiotic fermentation: Add 1% by mass of Lactobacillus plantarum to the red date pulp and ferment it at 35°C for 15 h to obtain red date pulp. The pulp was then stored in a refrigerator at 4°C for 10 h before use.

[0080] Comparative Example 6 A method for preparing low-sugar fermented red date pulp comprises the following steps: (1) Cleaning and pitting: Use bubbling and brushing to remove impurities such as loose soil on the surface of the red dates, drain them, remove the pits from the red dates and weigh them.

[0081] (2) Rehydration and softening: The pitted red dates are rehydrated with a solid-liquid ratio of 1:2 and soaked at room temperature for 2 h to fully soften the red dates and dissolve the soluble solids.

[0082] (3) Beating: Use an ultra-fine grinder to beat the red dates to obtain red date pulp.

[0083] (4) Probiotic fermentation: Add 1% by mass of Lactobacillus rhamnosus to the red date pulp and ferment at 35°C for 10 h to obtain red date pulp. The pulp was then stored in a refrigerator at 4°C for 10 h before use.

[0084] Comparative Example 7 A method for preparing low-sugar fermented red date pulp comprises the following steps: (1) Cleaning and pitting: Use bubbling and brushing to remove impurities such as loose soil on the surface of the red dates, drain them, remove the pits from the red dates and weigh them.

[0085] (2) Rehydration and softening: The pitted red dates are rehydrated with a solid-liquid ratio of 1:2 and soaked at room temperature for 2 h to fully soften the red dates and dissolve the soluble solids.

[0086] (3) Beating: Use an ultra-fine grinder to beat the red dates to obtain red date pulp.

[0087] (4) Probiotic fermentation: Add 1% by mass of Lactobacillus plantarum and 0.6% by mass of Lactobacillus rhamnosus to the red date pulp, ferment at 35°C for 10 h to obtain red date pulp, and store it in a refrigerator at 4°C for 10 h before use.

[0088] Comparative Example 8 A method for preparing low-sugar fermented red date pulp comprises the following steps: (1) Cleaning and pitting: Use bubbling and brushing to remove impurities such as loose soil on the surface of the red dates, drain them, remove the pits from the red dates and weigh them.

[0089] (2) Rehydration and softening: The pitted red dates are rehydrated with a solid-liquid ratio of 1:2 and soaked at room temperature for 2 h to fully soften the red dates and dissolve the soluble solids.

[0090] (3) Beating: Use an ultra-fine grinder to beat the red dates to obtain red date pulp.

[0091] (4) Probiotic fermentation: Add 0.3% by mass of Lactobacillus plantarum, 0.3% by mass of Lactobacillus rhamnosus and 0.4% by mass of Lactobacillus helveticus to the red date pulp and ferment at 35°C for 15 h to obtain red date pulp. Transfer the pulp to a 4°C refrigerator and store it for 10 h before use.

[0092] The materials of various embodiments and comparative examples were tested, and the results were as follows: Figure 1 The figure is a bar graph of the sucrose content of red date puree at each stage in Example 1, Example 2 and Example 3. It can be seen from the figure that the sucrose content in the red date juice without enzyme conversion and fermentation conversion is the highest, the sucrose content decreases after double-stage enzymatic hydrolysis, and the sucrose content is further reduced after fermentation.

[0093] Figure 2 It is a bar graph of the total sugar content of red date pulp at each stage in Example 1, Example 2, and Example 3.

[0094] Figure 3 The figure is a bar graph of the glucose content of red date puree at each stage in Example 1, Example 2 and Example 3. As can be seen from the figure, during the first stage of enzymatic hydrolysis, glucose byproducts are generated during the sucrose conversion process, and the glucose content decreases after the second stage of enzymatic hydrolysis.

[0095] Figure 4 It is a bar graph of the GI values ​​of different red date cakes prepared in Example 4, Example 5, Comparative Example 1, Comparative Example 2, Comparative Example 3, and Comparative Example 4. As can be seen from the figure, the red date cake prepared from original red date pulp, wheat flour, and white sugar in Comparative Example 1 has the highest GI value, and the red date cake prepared from fermented red date pulp, highland barley flour, black whole wheat flour, inulin, oat bran powder, psyllium husk powder, and L-arabinose has a gradually decreasing eGI value. It can be concluded from Examples 4 and 5 that the red date cake prepared according to the content of the present invention is a low-glycemic date cake.

[0096] Figure 5 The results of glucose content determination of red date pulp in comparative examples 5 to 8 after different fermentation treatments are shown in FIG. Figure 6 These are the results of determining the sucrose content of the red date purees in Examples 5 to 8 after different fermentation treatments. As can be seen from the figure, the hypoglycemic effect of mixed fermentation with Lactobacillus plantarum and Lactobacillus rhamnosus is better than that of fermentation with a single strain.

[0097] It should be noted that when the claims of the present invention involve numerical ranges, it should be understood that the two endpoints of each numerical range and any numerical value between the two endpoints can be selected. In order to avoid redundancy, the present invention describes a preferred embodiment.

[0098] Although the preferred embodiments of the present invention have been described, those skilled in the art may make other changes and modifications to these embodiments once they have learned the basic creative concept. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments and all changes and modifications that fall within the scope of the present invention.

[0099] Obviously, those skilled in the art can make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, if these modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalents, the present invention is also intended to include these modifications and variations.

Claims

1. A method for preparing low-sugar fermented red date pulp, comprising washing and removing pits, rehydrating and softening, and beating to obtain red date pulp, characterized in that: The following steps are also included: The first enzymatic hydrolysis: add 15U~25U fructosyltransferase to each gram of red date pulp for the first enzymatic hydrolysis, and inactivate the enzyme after the first enzymatic hydrolysis to obtain the first enzymatic hydrolysis product; The second enzymatic hydrolysis: adding 60U-70U glucose oxidase to each gram of the first enzymatic hydrolysis product for a second enzymatic hydrolysis, and inactivating the enzyme after the second enzymatic hydrolysis to obtain a second enzymatic hydrolysis product; Probiotic fermentation: adding 0.8% to 1% by mass of Lactobacillus plantarum and 0.8% to 1% by mass of Lactobacillus rhamnosus to each gram of the second enzymatic hydrolysis product, and obtaining the low-sugar fermented red date pulp after fermentation; Wherein, the temperature of the first enzymolysis is higher than the temperature of the second enzymolysis, and the time of the first enzymolysis is longer than the time of the second enzymolysis.

2. The preparation method according to claim 1, characterized in that: The temperature of the first enzymatic hydrolysis is 45°C to 55°C.

3. The preparation method according to claim 1, characterized in that: The time of the first enzymatic hydrolysis is 3.5h~4.5h.

4. The preparation method according to claim 1, characterized in that: The temperature of the second enzymatic hydrolysis is 30°C to 35°C.

5. The preparation method according to claim 1, characterized in that: The second enzymatic hydrolysis time is 2h~2.5h.

6. The preparation method according to claim 1, characterized in that: The rehydration and softening specifically comprises adding water to the pitted red dates at a material-liquid ratio of 1:2-2.5 and soaking for 2h-3h.

7. A method for preparing a low-glycemic red date cake, characterized in that: The following steps are involved: Taking eggs, separating them to obtain egg white and egg yolk, adding L-arabinose to the egg white, and beating the egg white to obtain whipped egg white; Add the low-sugar fermented red date paste and mixed powder according to claim 1 to the egg yolk, and mix well to obtain a batter; The mixed flour is composed of 60% to 70% highland barley flour, 10% to 15% black whole wheat flour, 5% to 8% inulin, 5% to 8% psyllium husk powder, 4.5% to 13.5% oat bran powder and 0.1% to 0.5% konjac flour. Take 1 / 3 of the beaten egg white and mix it with the batter to obtain paste 1, and mix paste 1 with the remaining 2 / 3 of the beaten egg white to obtain paste 2; The obtained paste is baked at 140° C. to 150° C. for 70 min to 80 min to obtain the low-glycemic red date cake.

8. The preparation method according to claim 7, characterized in that: The mass ratio of the low-sugar fermented red date pulp to the mixed powder is 2-2.5:1, and the mass ratio of the low-sugar fermented red date pulp to the L-arabinose is 20-25:1; the number of eggs is 1 / 15-20 of the weight of the cereal flour.

9. The preparation method according to claim 7, characterized in that: Bake at 140℃~150℃ for 70min~80min.

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