Chinese yam and oat biscuits and preparation method thereof

Abstract

The invention relates to the technical field of food processing, in particular to Chinese yam and oat biscuits and a preparation method thereof. The Chinese yam and oat biscuits comprise 73 parts of low-gluten flour, 27 parts of oat flour, 13.5-18 parts of Chinese yam homogenate, 30-40 parts of coconut oil, 40.9 parts of powdered sugar, 5 parts of whole milk powder, 10 parts of egg liquid and 3 parts of a compound leavening agent. The preparation method of the Chinese yam and oat biscuits comprises the following steps: pretreating raw materials; pre-mixing dry and wet materials; preparing dough; tabletting and forming; performing baking; cooling is performed; by adding a proper amount of oat powder, the crispness and flavor of the biscuit can be remarkably improved, and the sensory score is increased; the fresh Chinese yam is high in moisture, can provide moderate moisture for a dough system, and is beneficial to starch gelatinization and cross-linking among macromolecules during baking, so that the hardness and chewiness of the product are improved; the coconut oil and the mixed powder can form a uniform grease wrapping system, and finally a good crisp feeling is provided for the biscuit; the hydrolysis effect of digestive enzymes on starch can be partially inhibited after a proper amount of Chinese yam homogenate and oat are added.

Description

Technical Field

[0001] The invention relates to the technical field of food processing, in particular to a yam and oatmeal biscuit and a preparation method thereof. Background Art

[0002] Biscuits are a typical baked good, typically containing three main ingredients (flour, sugar, and fat) and a low water content. With changing social environments, cardiovascular and metabolic diseases are becoming increasingly prevalent, placing significant pressure on the health care system. In recent years, replacing some of the traditional flour and fat with ingredients rich in nutrients and possessing health benefits has become a hot topic in formulation innovation research. For example, a Chinese patent discloses a yam and oatmeal biscuit (CN201510824072), which is made from the following raw materials in parts by weight: 80 parts flour, 20-50 parts yam flesh, 20 parts oatmeal, 0.5-3 parts leavening agent, 15-30 parts sweetener, 20-50 parts fat, and 20-50 parts water. The beneficial effects of this invention are: using yam flesh to make biscuits combines the sweet taste of yam with the crispness of biscuits, while reducing the amount of sugar and calories in the biscuits. The addition of yam flesh makes the biscuits rich in dietary fiber, which facilitates digestion and prevents constipation, making them very suitable for obese people. The fat includes coconut oil.

[0003] Through practice, it was found that the above technical solution needs to be improved in terms of sensory score, and the starch hydrolysis rate is relatively high (not resistant to digestion). Summary of the Invention

[0004] In view of the shortcomings of the prior art, the present invention provides a yam oatmeal biscuit, which has excellent sensory scores and a low starch hydrolysis rate (digestion resistance). In addition, the present invention also provides a preparation method of the product.

[0005] The technical solution of the present invention is:

[0006] A yam oatmeal biscuit comprising the following raw materials in parts by weight:

[0007] 73 parts of low-gluten flour, 27 parts of oat flour, 13.5-18 parts of yam slurry, 30-40 parts of coconut oil, 40.9 parts of powdered sugar, 5 parts of whole milk powder, 10 parts of egg liquid and 3 parts of compound leavening agent.

[0008] In a preferred embodiment, the raw materials include the following parts by weight:

[0009] 73 parts of low-gluten flour, 27 parts of oat flour, 14.9 parts of yam slurry, 37.5 parts of coconut oil, 40.9 parts of powdered sugar, 5 parts of whole milk powder, 10 parts of egg liquid and 3 parts of compound leavening agent.

[0010] A method for preparing yam oatmeal biscuits comprises the following steps:

[0011] Step 1, weigh the raw materials of the formula;

[0012] Step 2: pretreatment of raw materials;

[0013] Step 3: Pre-mixing of dry and wet materials;

[0014] Step 4: dough preparation;

[0015] Step five, tableting;

[0016] Step 6: Bake;

[0017] Step seven, cooling;

[0018] Step 8: Packaging.

[0019] In a preferred embodiment, the raw material pretreatment includes pretreatment of coconut oil and preparation of yam homogenate.

[0020] Specifically, the pretreatment of the coconut oil includes: placing the coconut oil in a water bath at 30-99° C., heating and melting the coconut oil into a liquid state for later use.

[0021] Specifically, the preparation of the yam homogenate includes: peeling the fresh yam, putting it into a food processor and blending it until it is smooth and free of particles.

[0022] In a preferred embodiment, the sheeting includes: pressing the dough into a sheet with a thickness of 5.00 mm, and then pressing it into shape using a biscuit mold.

[0023] In a preferred embodiment, the baking includes: upper heat 165°C, lower heat 150°C, and baking for 14 minutes.

[0024] The beneficial effects of the present invention are as follows: adding an appropriate amount of oat flour can significantly improve the crispness and flavor of the biscuits, the oat aroma becomes more intense, the biscuit structure becomes crispy and porous, and the sensory score is improved; fresh yam has high moisture content, and adding yam homogenate to the formula can provide appropriate moisture to the dough system, which is beneficial to starch gelatinization and cross-linking between macromolecules during baking, thereby improving the hardness and chewiness of the product; coconut oil and mixed flour (low-gluten flour and oat flour) can form a uniform oil-coated system, and ultimately provide the biscuits with a good crisp feeling; and adding an appropriate amount of yam homogenate and oats can partially inhibit the hydrolysis of starch by digestive enzymes. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 Create a process flow chart for cookies;

[0026] Figure 2 The influence of various factors on biscuit quality;

[0027] Figure 3This is the response surface analysis diagram of the interaction effect of various factors on sensory scores;

[0028] Figure 4 Comparison of starch hydrolysis rates of biscuits with different recipes. DETAILED DESCRIPTION

[0029] The following is further explained in conjunction with specific implementation methods:

[0030] 1 Materials and Methods

[0031] 1.1 Raw materials and reagents

[0032] Fresh Chinese yam, harvested from Pimen Town, Yangjiang, Guangdong; oat flour (80 mesh, Dongguan Rilong Food Co., Ltd.); low-gluten wheat flour (Shanghai Fengwei Industrial Co., Ltd.); cold-pressed coconut oil (Hainan Hengcheng Xuguang Food Co., Ltd.); edible blending oil, commercially available; white sugar powder (Chengdu Taikoo Sugar Co., Ltd.); biscuit-specific compound leavening agent (Henan Honest Food Co., Ltd.); whole milk powder (Fonterra Group, New Zealand); anhydrous glucose (Guangdong Guanghua Technology Co., Ltd.); pepsin (30,000 U / g, Shanghai Yuanye Biotechnology Co., Ltd.); pancreatin (≥4,000 U / g, Shandong Keyuan Biochemical Co., Ltd.); α-amylase (3,000-5,000 U / g, Tianjin Huasheng Chemical Reagent Co., Ltd.); anhydrous ethanol (analytical grade, Sinopharm Chemical Reagent Co., Ltd.); 3,5-dinitrosalicylic acid (analytical grade, Shanghai MacLean Biochemical Technology Co., Ltd.).

[0033] 1.2 Main instruments

[0034] LA204E analytical balance (precision 0.0001 g, Mettler Toledo); X100-FTA texture analyzer (Weifang Dezhao Machinery Technology Co., Ltd.); THZ-103B constant temperature incubation shaker (Shanghai Yiheng Scientific Instrument Co., Ltd.); pH meter (Mettler Toledo); TU-1901 double-beam UV-visible spectrophotometer (Beijing Puxi General Instrument Co., Ltd.); MA600R centrifuge (Shanghai Fengbo Biotechnology Co., Ltd.).

[0035] 1.3 Basic biscuit recipe and production process

[0036] according to Figure 1 The process flow shown is used to make biscuits.

[0037] 1.4 Experimental Design

[0038] 1.4.1 Single-factor experiment

[0039] According to the preliminary experimental results of the basic formula of yam oatmeal cookies and the dosage range of key raw materials, a single-factor experiment was conducted. As shown in Table 1, the total mass of the mixed flour (low-gluten flour and oat flour) in each group was fixed at 200g, and the addition amount of each factor was based on the mixed flour. The effects of the factors on the sensory score and texture hardness of the cookies were explored.

[0040] Table 1 Single-factor settings

[0041]

[0042] 1.4.2 Response surface optimization experiment

[0043] Based on the single factor experiment, the addition amount of yam homogenate, oatmeal flour, coconut oil and powdered sugar was proposed as the independent variables, and the comprehensive sensory score was used as the response value. According to the Box-Benhnken central combination principle, a four-factor three-level experiment was designed to screen the optimal process formula of yam oatmeal cookies, as shown in Table 2.

[0044] Table 2 Factor and level design

[0045]

[0046] 1.4.3 Sensory Evaluation Standards

[0047] The evaluation team, comprised of 12 food science students, evaluated the quality of the yam oatmeal cookies after they were baked and cooled, based on four aspects: color, form, internal structure, and taste. The total score was 100 points. Each individual's score for each item was tallied and averaged. The sensory scoring criteria, developed with reference to GB / T 20980-2021, "General Rules for Biscuit Quality," are shown in Table 3.

[0048] Table 3 Sensory evaluation criteria for biscuits

[0049]

[0050]

[0051] 1.4.4 Biscuit hardness determination

[0052] The biscuits cooled for 30 minutes were tested for hardness using an X100-FTA texture analyzer with a P / 2 probe in TPA mode. The test parameters were: pre-test speed 2.0 mm / s, test speed 1.0 mm / s, post-test speed 2.0 mm / s, test displacement 2 mm, and trigger force 5.0 g. The test method is based on the results of He Zedong, Feng Hui, Wang Lingyan, et al. Effect of white ginseng powder addition on biscuit quality and starch digestibility [J]. Food Industry Science and Technology, 2025, 46(09): 85-92.

[0053] 1.4.5 In vitro simulated digestion experiment

[0054] Artificial saliva (650 U / mL), artificial gastric juice, and artificial small intestinal fluid were prepared according to the Pharmacopoeia of the People's Republic of China and the literature (He Ruiqi, Xu Xiaofei. Development of a low-GI multi-grain noodle [J]. Agricultural Products Processing, 2023, (11): 1-4+8.) and refrigerated for later use. Optimized formula biscuits: Prepared according to the optimized formula using response surface methodology. Control Example 1 (biscuits): No oatmeal was added but Chinese yam homogenate was added; Control Example 2 (biscuits): Biscuits without oatmeal and Chinese yam homogenate.

[0055] Example 1: 73g low-gluten flour, 27g oat flour, 14.9g yam homogenate, 37.5g coconut oil, 40.9g powdered sugar, 5g whole milk powder, 10g egg liquid, and 3g compound leavening agent.

[0056] Example 2: 73g low-gluten flour, 27g oat flour, 18.0g yam homogenate, 30.0g coconut oil, 40.9g powdered sugar, 5g whole milk powder, 10g egg liquid, and 3g compound leavening agent.

[0057] Example 3: 73g low-gluten flour, 27g oat flour, 13.5g yam homogenate, 40.0g coconut oil, 40.9g powdered sugar, 5g whole milk powder, 10g egg liquid, and 3g compound leavening agent.

[0058] Control Example 1: 100g low-gluten flour, 14.9g yam slurry, 37.5g coconut oil, 40.9g powdered sugar, 5g whole milk powder, 10g egg liquid, and 3g compound leavening agent.

[0059] Control Example 2: 100g low-gluten flour, 37.5g coconut oil, 40.9g powdered sugar, 5g whole milk powder, 10g egg liquid, and 3g compound leavening agent.

[0060] Control example 3: 60g low-gluten flour, 40g oatmeal flour, 50g yam paste, 40g xylitol, 40g blending oil, 4g whole milk powder, 4g egg liquid, 0.3g salt, 1.5g baking soda, 0.8g monoglyceride, 0.2g citric acid (prepared according to the literature: Yuan Guiying, Wang Yanping, Ji Changxin, et al. Effects of purple yam and oatmeal flour on the quality and nutritional characteristics of crispy biscuits [J]. Food Research and Development, 2022, 43(17): 100-106).

[0061] Control Example 4: 80g low-gluten flour, 20g oatmeal flour, 30g yam granules, 30g powdered sugar, 50g blending oil, 30g water, 3g compound leavening agent (the proportion of raw materials refers to invention patent 201510824072.2, a yam oatmeal biscuit).

[0062] References for in vitro simulated digestion (He Ruiqi, Xu Xiaofei. Development of a low-GI multi-grain noodle[J]. Agricultural Products Processing, 2023, (11): 1-4+8.; MINEKUS M, ALMINGER M, ALVITO P, et al. A standardised static in vitro digestion method suitable for food-an international consensus[J].Food&Function.2014,5(6):1113-24.), 3 biscuits were ground in a mortar to a particle size of about 0.5-2 mm, passed through a 20-mesh sieve, 5 g of the sample was weighed and mixed with 5 mL of artificial saliva (preheated at 37 ° C) for 2 min, 4 g of the above mixture was added to 40 mL of simulated gastric fluid and shaken at 37 ° C in a constant temperature shaking incubator at 120 r / min for 2 h, and immediately after simulated gastric digestion, 1 mol / L sodium hydroxide was used to adjust the pH to 6.9, and then 40 mL of intestinal fluid was added, mixed and placed in a constant temperature shaking incubator at 37 ° C and 120 r / min for enzymatic hydrolysis, respectively at 0, 15, 30, 60, 90, 120, 150, and 180 min, 2 mL of the supernatant was taken into a centrifuge tube, and 2 mL of anhydrous ethanol was added to inactivate the enzyme. Centrifuge at 8000 r / min for 5 min, and determine the amount of reducing sugar produced by the 3,5-dinitrosalicylic acid method (for the determination method, refer to Deng Kaibo, Huang Yaping, Tu Yingjing, et al. Process optimization and digestibility evaluation of Tremella crispy biscuits [J]. Food Research and Development, 2018, 39(19): 79-85.). The starch hydrolysis rate (HR) in the biscuits was calculated according to formula (1):

[0063]

[0064] Wherein, HR is the hydrolysis rate, %; G is the reducing sugar content after hydrolysis at different times, mg; W is the mass of starch in the sample, mg;

[0065] 1.5 Statistics

[0066] The values ​​are expressed as mean ± standard deviation. Each group of samples was measured at least 3 times in parallel. OriginPro 2024 was used for data processing and graphing.

[0067] 2 Results and Analysis

[0068] 2.1 Single-factor experimental results

[0069] 2.1.1 Effect of oat flour addition on quality

[0070] Adding an appropriate amount of oat flour can significantly improve the crispness and flavor of the biscuits. As the amount added increases, the oat aroma becomes richer, the biscuit structure becomes crisper and more porous, and the sensory score gradually increases. Figure 2 It can be seen that when the oat flour addition amount is 30%, the sensory score of the biscuits reaches the highest value. When the addition amount exceeds 40%, the gluten network formation of the dough will be destroyed, the biscuits will be difficult to shape, the taste will deteriorate, and the hardness value and sensory score will decrease.

[0071] 2.1.2 Effect of the amount of yam homogenate added on quality

[0072] Fresh yam has high moisture content. Adding yam homogenate to the formula can provide appropriate moisture to the dough system, which is beneficial to starch gelatinization and cross-linking between macromolecules during baking, thereby improving the hardness and chewiness of the product. Figure 2 b It can be seen that when the addition amount of yam homogenate is 15%, the sensory score of the biscuits reaches the highest value. Continuing to increase the addition amount of yam homogenate will cause the dough to be too wet and difficult to shape. The baked biscuits will collapse inside and have a sticky taste. The hardness and sensory score will drop sharply.

[0073] 2.1.3 Effect of coconut oil addition on quality

[0074] Crisp biscuits are W / O type biscuits. The fat in the dough is stretched into a thin film and covers the surface of the particles. On the one hand, it can carry air into the dough, and on the other hand, it can block the connection between starch particles through the hydrogen bonds of water molecules, making the biscuits loose due to the expansion of air due to heat during baking. Figure 2 As shown in Figure 3, when the addition level is 40%, coconut oil and the mixed flour form a uniform oil-coating system, ultimately providing the cookies with a good crispness. However, when the addition level exceeds 40%, the excessive oil reduces the stickiness of the dough and causes oil leakage, resulting in loose cookies that are difficult to shape and have poor crack resistance. The morphology score differs significantly from other groups. When the addition level is below 35%, the product becomes dry and hard, with reduced crispness, and the sensory score decreases.

[0075] 2.1.4 Effect of powdered sugar addition on quality

[0076] Depend on Figure 2 As can be seen from the figure, at a 50% addition, the natural flavors of yam and coconut oil were less pronounced in the cookies, and the excessive sweetness even caused a cloying sensation. At a 30% addition, the sweetness was insufficient, resulting in a lower sensory score. Adding 40% powdered sugar resulted in a uniform, attractive browning reaction and the production of good flavor compounds. Further increases in the addition level resulted in a cloyingly sweet taste and increased hardness, leading to a decrease in acceptance. During baking, powdered sugar imparts a golden color and a burnt aroma to the cookies through Maillard and caramelization reactions.

[0077] 2.2 Response surface formulation optimization

[0078] On the basis of the results of the single-factor experiment, four factors were used as independent variables and the sensory evaluation score (Y) was used as the response value. A total of 29 test points were conducted. The response surface design and evaluation results are shown in Table 4.

[0079] Table 4 Response surface design and the corresponding results

[0080]

[0081]

[0082] The quadratic polynomial regression fitting was performed on the experimental data in Table 4 to obtain the quadratic multiple regression equation: Y = 86.19-5.07A-1.55B+1.97C-1.66D-2.09AB+6.05AC+0.5762AD-0.9307BC+0.9398BD+0.9062CD-8.69A 2 -2.25B 2 -7.35C 2 -5.31D 2 The variance analysis of the model fitted by the test results is shown in Table 5.

[0083] Table 5 Analysis of variance of quadratic multiple regression equation

[0084] Table 5Variance analysis of regression equation

[0085]

[0086]

[0087] Note: “*” indicates significant difference (P<0.05); “**” indicates extremely significant difference (P<0.01)

[0088] Table 5 shows that the sensory evaluation regression model for yam and oatmeal cookies had a P value less than 0.01, and the lack-of-fit term (P = 0.5587) was greater than 0.05, indicating that the quadratic regression equation is acceptable. Since the model reached an extremely significant level, with a goodness-of-fit of 0.9981 and a corrected goodness-of-fit of 0.9913, it demonstrated that the model fitted the sensory optimization test well. The linear relationship between the independent variables and the response values ​​was significant, indicating that it could be used to determine the optimal cookie recipe. The linear terms A, B, C, and D had P values ​​less than 0.01, indicating that the amount of yam homogenate, coconut oil, powdered sugar, and oat flour added had a highly significant effect on the sensory scores. The interaction terms AB, AC, BC, BD, and CD had P values ​​less than 0.01, indicating that the interactions between the factors were highly significant. The F-values ​​indicate that the order of influence of the factors on the sensory scores of the cookies was: yam homogenate amount (A) > powdered sugar amount (C) > oat flour amount (D) > coconut oil amount (B).

[0089] The sensory score response surface diagram and contour map of the interaction of various factors are shown in Figure 3 .Depend on Figure 3 As shown in the figure, the response surfaces of the interaction of each factor all show a convex opening downward shape, indicating that the sensory score (Y) has a maximum value and the optimal process parameters are within the experimental design range. Among them, the amount of yam homogenate and coconut oil added (AB) ( Figure 3 a) Yam homogenate and sugar powder addition (AC) Figure 3 The interaction effect of b) is the most significant, which is manifested by the steep slope of the response surface and the obvious elliptical contour line.

[0090] 2.3 Formulation Optimization Verification

[0091] According to the response surface model, the optimal formula parameters of biscuits are obtained: the mass ratio of cake flour and oat flour is 73:27 as the base number, the yam homogenate is 14.94%, coconut oil is 37.52%, and icing sugar is 40.89%, and the final sensory score is 86.75. Based on actual operation feasibility, the optimal conditions are revised to cake flour 73g, oat flour 27g, yam homogenate consumption 14.9g, coconut oil consumption 37.5g, and icing sugar consumption 40.9g. Carry out 3 verification tests, the sensory score mean value of the obtained yam biscuits is 86.79 points, and the actual value is consistent with the theoretical value, which shows that the mathematical model obtained by the response surface experiment is reliable and has practical value. Sensory evaluation is carried out to other embodiments and reference examples samples at the same time, and the results are shown in Table 6.

[0092] Table 6 Sensory evaluation results of biscuit samples

[0093]

[0094]

[0095] 2.4 Digestive properties of biscuits

[0096] Depend on Figure 4 As can be seen, during the first 60 minutes of simulated digestion, the starch hydrolysis rate in the biscuits climbed rapidly. After 60 minutes, the rate slowed significantly. By 180 minutes, the starch hydrolysis rates of the optimized biscuits (Examples 1-3) were between 79.23% and 81.11%, while the starch hydrolysis rates of the biscuits in the control groups 1-4 reached 84.58% to 90.71%, respectively, with statistically significant differences (p < 0.05). Clearly, throughout the entire digestion process, the hydrolysis rates of the optimized formulas were lower than those of the four control formulas. These results demonstrate that the biscuits in the examples possess excellent digestibility and are healthy biscuits suitable for modern consumers.

Claims

1. A yam oatmeal biscuit, characterized in that: The following raw materials are included in parts by weight: 73 parts of low-gluten flour, 27 parts of oat flour, 13.5-18 parts of yam slurry, 30-40 parts of coconut oil, 40.9 parts of powdered sugar, 5 parts of whole milk powder, 10 parts of egg liquid and 3 parts of compound leavening agent.

2. The yam oatmeal biscuit according to claim 1, characterized in that: The following raw materials are included in parts by weight: 73 parts of low-gluten flour, 27 parts of oat flour, 14.9 parts of yam slurry, 37.5 parts of coconut oil, 40.9 parts of powdered sugar, 5 parts of whole milk powder, 10 parts of egg liquid and 3 parts of compound leavening agent.

3. A method for preparing the yam oatmeal biscuits according to claim 1, comprising the following steps: Step 1, weigh the raw materials of the formula; Step 2: pretreatment of raw materials; Step 3: Pre-mixing of dry and wet materials; Step 4: dough preparation; Step five, tableting; Step 6: Bake; Step seven, cooling; Step 8: Packaging.

4. The method for preparing yam oatmeal biscuits according to claim 3, wherein: The raw material pretreatment includes the pretreatment of coconut oil and the preparation of yam homogenate.

5. The method for preparing yam oatmeal biscuits according to claim 4, characterized in that: The coconut oil pretreatment comprises: placing the coconut oil in a water bath at 30-99° C. and heating and melting the coconut oil into a liquid state for later use.

6. The method for preparing yam oatmeal biscuits according to claim 4, characterized in that: The preparation of the yam homogenate comprises the following steps: peeling the fresh yam, putting the yam into a food processor and blending the yam until the yam is smooth and free of particles.

7. The method for preparing yam oatmeal biscuits according to claim 3, characterized in that: The sheeting process comprises: pressing the dough into sheets with a thickness of 5.00 mm, and then pressing the sheets into shape using a biscuit mold.

8. The method for preparing yam oatmeal biscuits according to claim 3, characterized in that: The baking comprises: upper heat 165° C., lower heat 150° C., and baking for 14 minutes.

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