Method for measuring starch swelling volume and its application in predicting stability of yoghurt

Abstract

The present application relates to yogurt performance prediction, in particular to a starch swelling volume detection method and application in predicting yogurt stability. The starch swelling volume detection method comprises: subjecting starch paste obtained by gelatinization reaction of the to-be-detected starch in a solvent system to cold storage and standing, and then observing the volume of starch precipitation; the solvent system is selected from one or more of a water system, an emulsion system and a plant-based system. The method of the present application has wide application range, and can objectively and accurately evaluate the gelatinization degree of starch, directly observe the swelling degree of starch, and thus indirectly evaluate the stability system of yogurt.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of yogurt performance prediction, and particularly relates to a starch swelling volume detection method and application thereof in predicting yogurt stability. BACKGROUND

[0002] Starch, as one of the important raw materials of yogurt, can provide different properties and textures after being heated and gelatinized, and can make the yogurt thick, increase the smooth feeling of the beverage, and make the beverage non-sticky and rigid. The gelatinization degree of starch can directly affect the stability, viscosity and water holding capacity of the product, and is crucial to the quality of yogurt.

[0003] There are three common methods for detecting the gelatinization degree of starch. Two of the methods are based on water system, in which starch and water are mixed into a certain proportion of starch milk, heated and gelatinized, and the gelatinization degree is calculated by centrifugal precipitation. Although this method has a fast detection time, it is not suitable for milk system, because the centrifugation will make the fat in the milk float and the protein sink, resulting in inaccurate detection results. The third method is to directly use a microscope to observe the staining of starch particles. This method can directly observe the condition of starch particles, but the difference between different visual fields is large, the repeatability is poor, and the protein and fat in the milk system will affect the results. For example, Li Yang (Research on Physical Treatment and Physicochemical Properties of Millet Starch[D]. Tianjin University of Science and Technology, 2019.) used millet starch as raw material, applied ultrasonic and microwave technology to treat millet starch, and compared the viscosity properties, thermal properties, swelling power, transparency, particle size and crystal structure of starch paste under the two modification methods. Wang Lin (Study on Gelatinization and Gel Properties of Starch and Food Quality[J]. Preservation and Processing, 2021, 21(02): 67-73.) used various starch raw materials commonly used in the market as test materials to explore the basic components, solubility, swelling degree, gelatinization properties, gel properties and sensory scores of cereal starch (wheat starch, corn starch), potato starch (potato starch, sweet potato starch, cassava starch), and legume starch (pea starch, mung bean starch). Zhao Yongqing et al. (Effect of Heat-alcohol Treatment on Polarization Properties of Corn Starch Particles[J]. Grain and Feed Industry, 2010(06): 21-23.) used corn starch as raw material, observed by optical microscope and polarizing microscope, studied the influence of different conditions of ethanol and heating on the morphology and polarization properties of corn starch particles and the law of its change with these factors; when the heating temperature is 85℃, the ethanol mass fraction is 40%, and the starch milk mass fraction is 20%, a non-crystalline starch sample with completely disappeared cross-polarization and still maintaining the integrity of the particles can be prepared. Some of the existing methods cannot obtain the swelling degree of starch as a whole, or cannot be applied to water system, emulsion system, plant-based system, etc. At present, how to provide a detection method that can objectively and accurately evaluate the gelatinization and swelling degree of starch and is suitable for multiple systems, and can evaluate the stability system of yogurt, is an important topic to be solved in the field. SUMMARY

[0004] To solve the above technical problems, the present application provides a method for detecting starch swelling volume and its application in predicting the stability of yogurt. The method provided by the present application has a wide range of applications, and can objectively and accurately evaluate the gelatinization degree of starch, and can directly observe the swelling degree of starch, thereby indirectly evaluating the stability system of yogurt.

[0005] Specifically, the present application first provides a method for detecting starch swelling volume, comprising:

[0006] subjecting the starch to be tested to gelatinization reaction in a solvent system to obtain starch paste;

[0007] subjecting the starch paste to cold storage and standing, and then measuring the volume of starch precipitation;

[0008] The solvent system is selected from one or more of water system, emulsion system and plant-based system.

[0009] The present application finds that the method of the present application simulates the standing process of the product, does not use external force, and can directly observe the starch swelling volume, evaluate the gelatinization degree of starch, and thus predict the stability of yogurt, which is suitable for water system, emulsion system and plant-based system, has a wide range of applications, and the detection method of the present application can cover the main base system of current yogurt production; can indirectly predict the stability of yogurt system; does not introduce foreign substances, and does not destroy the original system; the result can be directly read, and the repeatability is high.

[0010] According to the method for detecting starch swelling volume provided by the present application, the cold storage standing time is 60-90h.

[0011] According to the method for detecting starch swelling volume provided by the present application, the cold storage standing is carried out at-1-8℃; preferably, the cold storage temperature is 2-4℃. The present application selects the above cold storage temperature and time, which is beneficial to the sedimentation of starch particles, and the result reading is more accurate.

[0012] According to the method for detecting starch swelling volume provided by the present application, the gelatinization reaction is carried out under stirring condition for 5-10min, and then carried out for 15-20min without stirring.

[0013] According to the method for detecting starch swelling volume provided by the present application, the stirring is carried out at a rotation speed of 300-500r / min. The present application finds that the effect is optimal under the above stirring condition and rotation speed.

[0014] According to the method for detecting starch swelling volume provided by the present application, the gelatinization reaction is carried out under water bath condition, and the temperature is 90-95℃.

[0015] According to the starch swelling volume detection method provided by the application, in the gelatinization reaction, the dry weight of the starch to be detected and the weight of the solvent system are in a ratio of 2-8:100.

[0016] According to the starch swelling volume detection method provided by the application, in the gelatinization reaction, the dry weight of the starch to be detected and the weight of the solvent system are in a ratio of 2-8:100.

[0017] According to the starch swelling volume detection method provided by the application, in the gelatinization reaction, the dry weight of the starch to be detected and the weight of the solvent system are in a ratio of 2-8:100.

[0018] According to the starch swelling volume detection method provided by the application, in the gelatinization reaction, the dry weight of the starch to be detected and the weight of the solvent system are in a ratio of 2-8:100.

[0019] 1) The starch to be detected is mixed with a solvent system to obtain a mixed solution; the content of the starch to be detected in the mixed solution is 2-8 wt% based on the dry weight of the starch to be detected, and the dry weight of the starch to be detected is at least 1 g;

[0020] 2) The mixed solution is heated in a water bath at 90-95 DEG C under stirring for 5-10 min, then heated in a water bath without stirring for 15-20 min, and then cooled to room temperature in a water bath at 20-25 DEG C to obtain a starch paste;

[0021] 3) A part of the starch paste is taken and placed in a measuring cylinder, so that the dry weight of the starch to be detected in the taken starch paste is 1 g, the solvent system is added to 100 mL, and the mixture is stored in a refrigerator for 60-90 h; then, independent light source irradiation is performed in a dark environment, and the volume of the starch precipitate is observed.

[0022] The application further provides application of the starch swelling volume detection method in any of the following aspects:

[0023] (1) preliminary screening of yogurt raw material starch;

[0024] (2) determination of starch gelatinization temperature in the development process of a yogurt product;

[0025] (3) evaluation of yogurt stability.

[0026] The application has at least the following beneficial effects:

[0027] 1) The method is suitable for different sources and processing methods of starch, and is also suitable for observation of starch swelling volume in different systems.

[0028] 2) The swelling volume measured by the method of the present application can indirectly predict the stability of the yogurt;

[0029] 3) The method of the present application does not introduce foreign substances, does not exert any external force on the system, and does not cause any damage to the system;

[0030] 4) The method of the present application can directly observe the results, quantify the swelling degree of starch particles, and has universality. BRIEF DESCRIPTION OF DRAWINGS

[0031] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the drawings needed to be used in the embodiments or prior art description will be briefly introduced below. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can also be obtained by those skilled in the art without creative labor on the basis of these drawings.

[0032] Figure 1 The detection process schematic diagram provided for the embodiments of the present application;

[0033] Figure 2 The starch swelling volume schematic diagram in the water system in the embodiments of the present application;

[0034] Figure 3 The starch swelling volume schematic diagram in the milk system in the embodiments of the present application;

[0035] Figure 4 The starch swelling particle observation schematic diagram under the microscope in different fields of view in Comparative Example 3 of the present application;

[0036] Figure 5 The starch swelling particle observation schematic diagram under the microscope in Comparative Example 7 (left) and Example 1 (right) of the present application. DETAILED DESCRIPTION

[0037] In order to make the purpose, technical solutions and advantages of the embodiments of the present application more clear, the technical solutions in the embodiments of the present application will be described clearly and completely below in combination with the drawings in the embodiments of the present application. The following embodiments are used to illustrate the present application, but not to limit the scope of the present application. If the specific technology or condition is not specified in the embodiments, it is carried out according to the technology or condition described in the literature in the art, or according to the product instruction. If the reagent or instrument is not specified by the manufacturer, it is a conventional product that can be purchased through a regular channel.

[0038] Example 1 (direct observation method for measuring the swelling volume of starch in water system)

[0039] As Figure 1As shown, the embodiment provides a method for detecting the swelling volume of starch in a water system, which specifically comprises the following steps:

[0040] (1) The moisture content of waxy corn starch was measured by Mettler-Toledo moisture meter to be 11.5%, and the amount of waxy corn starch at 5% dry basis was calculated.

[0041] (2) 100g of water was weighed in a beaker, 5.61g of waxy corn starch was added and evenly dispersed, and then placed in a water bath for heating.

[0042] (3) The water bath was heated to 95℃, and the stirring speed was set to 300r / min for 10min. The beaker was taken out, covered with plastic wrap, and placed back in the 95℃ water bath for 20min without stirring.

[0043] (4) After the starch was completely gelatinized, it was cooled to room temperature in a 20℃ water bath, and distilled water was added to make up for the water evaporated.

[0044] (5) 20g of starch paste was taken in a 100mL measuring cylinder, distilled water was added to 100mL, so that the concentration of the prepared starch was 1g dry basis net weight per 100mL water, and the mixture was placed in a 4℃ refrigerator for 72h before observation.

[0045] (6) In a dark environment, the precipitate corresponding to the number of marks was the swelling volume under the illumination of an independent light source.

[0046] (7) The swelling volume V value was recorded as 18.5.

[0047] Comparative Example 1

[0048] This comparative example provides a direct observation method for measuring the swelling volume of starch in a water system (different gelatinization temperature intervals are set), which comprises the following steps:

[0049] (1) The moisture content of the starch was measured by Mettler-Toledo moisture meter, and the amount of modified starch at 5% dry basis was calculated.

[0050] (2) 100g of water was weighed in a beaker, 5.61g of waxy corn starch was added and evenly dispersed, and then placed in a water bath for heating.

[0051] (3) Different temperature intervals for starch gelatinization were set, 65-70℃ (70℃ was taken), 70-75℃ (75℃ was taken), 75-80℃ (80℃ was taken), 80-85℃ (85℃ was taken), 85-90℃ (90℃ was taken), 90-95℃ (95℃ was taken), 95-100℃ (100℃ was taken), and the stirring speed was set to 300r / min for 10min. The beaker was taken out, covered with plastic wrap, and placed back in the water bath for 20min without stirring.

[0052] (4) After the starch was completely gelatinized, it was cooled to room temperature in a 20℃ water bath, and distilled water was added to make up for the water evaporated.

[0053] (5) Take 20 g of starch paste in a 100 mL graduated cylinder, add distilled water to 100 mL, so that the concentration prepared is 1 g of starch dry basis net weight per 100 mL of water, and observe after 72 h of cold storage at 4°C.

[0054] (6) Under dark environment, independent light source irradiation, record the V value of starch at different pasting temperature gradient.

[0055] Measure the modified starch under different starch sources and different treatment methods, and the results show that: at 90-95°C (95°C), the degree of starch pasting is best, and the swelling volume V value is maximum, therefore, 90-95°C (95°C) is selected as the pasting temperature interval.

[0056] Table 1 Swelling volume V value of starch at different pasting temperature gradient

[0057]

[0058]

[0059] Comparative Example 2

[0060] This comparative example provides a method for measuring the swelling volume of starch in water system by centrifugal observation method (without 72 h storage, direct centrifugal observation), including the following steps:

[0061] (1) The moisture content of waxy corn starch is 11.5% measured by Mettler-Toledo moisture meter, and the amount of denatured starch of 5% dry basis is calculated.

[0062] (2) Weigh 100 g of water in a beaker, add 5.61 g of starch, and disperse uniformly, and place in a water bath for heating.

[0063] (3) Heat the water bath to 95°C, continuously stir at 300 r / min for 10 min. Take out the beaker, cover it with plastic wrap, and put it back in the 95°C water bath, and hold the temperature for 20 min without stirring.

[0064] (4) After the starch is completely pasted, cool it in a 20°C water bath to room temperature, and supplement the evaporated water with distilled water.

[0065] (5) Take 20 g of starch paste, add it to a centrifuge tube, and add distilled water to 50 mL, so that the concentration prepared is 1 g of starch dry basis net weight per 100 mL of water.

[0066] (6) Centrifuge with a Thermo centrifuge at 3500 r / min for 20 min.

[0067] The results show that after centrifugation, the sediment volume is obviously smaller than the swelling volume obtained in Example 1, because after starch gelatinization, starch particles swell and break under the action of external force, resulting in inaccurate detection.

[0068] Comparative Example 3

[0069] This comparative example provides a method for measuring the swelling volume of starch in a water system by microscope observation (without using light source irradiation, direct microscope observation), including the following steps:

[0070] Step 1: starch gelatinization, this step is the same as steps (1)-(5) of Example 1.

[0071] Step 2: microscope observation.

[0072] A small amount of starch sample is placed on a glass slide, diluted uniformly, and a drop of 0.1N iodine solution is added, mixed uniformly with a toothpick, mainly without generating bubbles, covered with a cover glass, and the excess liquid is removed with filter paper. Adjust the field of view with a low-power microscope and observe the shape with a 200x microscope to observe the size of the starch particles.

[0073] The results show that, as Figure 4 In the left and right images, the gelatinization degree of starch particles under different fields of view is different, and the swelling degree is different, which cannot reflect the whole and cannot evaluate the starch gelatinization as a whole. The swelling degree of starch cannot be quantified.

[0074] Comparative Example 4

[0075] This comparative example adds a color reagent to measure the swelling volume of starch in a water system by observation (without using light source irradiation, directly adding a color reagent to observe), including the following steps:

[0076] (1) The moisture content of waxy corn starch is measured by Mettler-Toledo moisture meter to be 11.5%, and the denatured starch is calculated at 5% dry basis.

[0077] (2) 100g of water is weighed in a beaker, 5.61g of starch is added and dispersed uniformly, and placed in a water bath.

[0078] (3) The water bath is heated to 95℃, and continuously stirred at 300r / min for 10min. The beaker is taken out, covered with plastic wrap, and placed back in the 95℃ water bath for 20min without stirring.

[0079] (4) After the starch is completely gelatinized, it is cooled to room temperature in a 20℃ water bath, and distilled water is added to make up for the water evaporated.

[0080] (5) Prepare a 1‰ concentration of water-soluble carmine solution.

[0081] (6) Take 20 g of starch paste in a centrifuge tube, add the prepared carmine aqueous solution to 100 mL, so that the prepared concentration is 1 g of starch dry basis net weight per 100 mL of solvent.

[0082] (7) After 72 h of standing in a 4°C refrigerator, observe.

[0083] The results show that in the system with added carmine, no precipitate interface is observed, and the starch swelling volume cannot be obtained.

[0084] Comparative Example 5

[0085] This comparative example provides a starch swelling degree detection method, including the following steps: accurately measure a certain mass (m1) of starch sample, prepare a 2% starch milk, heat in a 90°C environment for 30 min, then centrifuge at 3500 r / min for 20 min at 4°C, and weigh the precipitate (m2). The swelling degree (B) is calculated according to the following formula:

[0086] Swelling degree (g / g) = m2 / [m1(1-S)] x 100

[0087] Results: After starch milk gelatinization, starch particles are heated and expanded, and are very easy to break under external force, resulting in inaccurate evaluation results; and starch gelatinization temperature ranges of different sources and treatments are different, so the application range of this method is small.

[0088] Comparative Example 6

[0089] This comparative example provides a starch transparency detection method, including the following steps: accurately weigh 1.00 g of starch sample, put it into a 200 mL glass beaker, add distilled water to 100 g, stir uniformly, prepare a 1% starch milk, heat and gelatinize in a boiling water bath for 20 min, continuously stir at 300 r / min for the first 5 min of the starch gelatinization process to prevent starch clumping, and after the starch is completely gelatinized, naturally cool to room temperature for standby. At a wavelength of 650 nm, use distilled water as a blank, use a spectrophotometer to measure the light transmittance, measure each sample 3 times, and finally take the average value as the transparency of the sample. The application range of this method is small, and it is only suitable for comparison before and after gelatinization of a single sample, and is not suitable for comparison of gelatinization degree of different starches and systems. Starches of different sources and systems themselves have different colors and transparencies, which will affect the accuracy of the results.

[0090] Comparative Example 7

[0091] This comparative example provides a detection method for swelling volume (using light source irradiation + direct microscope observation) in a starch salted buffer solution system, including the following steps:

[0092] (1) Mettler-Toledo moisture meter to measure the moisture content of waxy corn starch is 11.5%, calculate the amount of 5% dry basis waxy corn starch.

[0093] (2) Weigh 100g of salted buffer solution in a beaker, add 5.61g of waxy corn starch, disperse evenly, and place in a water bath.

[0094] (3) Heat the water bath to 95℃, continuously stir at 300r / min for 10min. Take out the beaker, cover it with plastic wrap, and put it back in the 95℃ water bath. Hold the temperature for 20min without stirring.

[0095] (4) After the starch is completely gelatinized, cool it in a 20℃ water bath to room temperature, and supplement the water evaporated with distilled water.

[0096] (5) Take a small amount of starch sample on a glass slide, dilute it evenly, add a drop of 0.1N iodine solution, mix it evenly with a toothpick, and make sure there are no bubbles. Cover it with a cover glass, remove the excess liquid with filter paper, adjust the field of view with a low power microscope, and observe the shape with a 200x microscope.

[0097] (6) At the same time, take 20g of starch paste in a 100mL measuring cylinder, add salted buffer solution to 100mL, so that the concentration of the prepared starch is 1g dry basis net weight per 100mL water. After standing at room temperature for 24h, observe the results.

[0098] (7) In a dark environment, use independent light source to illuminate, and the corresponding number of precipitates is the swelling volume.

[0099] (8) Record the swelling volume V value as 18.

[0100] As Figure 4 The microscope results show that the gelatinization degree of the starch measured in Comparative Example 7 (right) and Example 1 (left) is not significantly different, and the swelling size of the starch particles is not significantly different. The swelling volume results show that the swelling volume measured by the comparative example method is significantly smaller than the measurement results of Example 1, which is mainly because the standing time of the example is long and the cold storage temperature is low, the molecular motion is slow, and the molecular sedimentation is more complete, so the results are more accurate.

[0101] Example 2 (Swelling Volume Observation of Starch in Milk System)

[0102] This example provides a method for detecting the swelling volume of starch in a milk system, which includes the following steps:

[0103] (1) Mettler-Toledo moisture meter to measure the moisture content of starch, calculate the amount of 2% dry basis denatured starch.

[0104] (2) Weigh 100g of milk in a beaker, add starch, disperse evenly, and place in a water bath.

[0105] (3) Water bath heating to 90℃, 300r / min continuous stirring for 5 min. Take out the beaker cover with plastic wrap, put back in 90℃ water bath, in the case of no stirring temperature 20 min.

[0106] (4) After starch gelatinization completely in 20℃ water bath cooling to room temperature, with milk to make up the water evaporation.

[0107] (5) Take 50g starch paste in 100mL measuring cylinder, add milk to 100mL, so that the concentration of 1g starch dry basis net weight / 100mL milk, 2℃ cold storage for 90h observation.

[0108] (6) In the dark environment, independent light source irradiation, precipitation corresponding to the number of scores is the swelling volume V value.

[0109] Example 3-5: Starch in plant-based system swelling volume observation and yogurt stability evaluation

[0110] Example 3 (starch in soybean system swelling volume observation)

[0111] This example provides a method for detecting the swelling volume of starch in a soybean system, comprising the following steps:

[0112] First step: preparation of soybean juice system

[0113] According to the ratio of 1:3 of soybean milk and distilled water, the soybean juice system is prepared, 60℃, stirring for 10 min.

[0114] Second step: observation of the swelling volume of starch in the soybean juice system.

[0115] (1) Mettler-Toledo moisture meter to determine the moisture content of starch, calculate the 4% dry basis amount of modified starch.

[0116] (2) Use a beaker to weigh 100g of soybean juice, add starch, disperse evenly, and place in a water bath.

[0117] (3) Water bath heating to 90℃, 300r / min continuous stirring for 10 min. Take out the beaker cover with plastic wrap, put back in 90℃ water bath, in the case of no stirring temperature 15 min.

[0118] (4) After starch gelatinization completely in 20℃ water bath cooling to room temperature, with soybean juice to make up the water evaporation.

[0119] (5) Take 25g starch paste in 100mL measuring cylinder, add soybean juice to 100mL, so that the concentration of 1g starch dry basis net weight / 100mL soybean juice, 4℃ cold storage for 90h observation.

[0120] (6) In a dark environment, independent light source irradiation, the corresponding number of precipitated marks is the swelling volume V value.

[0121] (7) Record the swelling volume V value as 30.

[0122] Example 4 (Observation of Swelling Volume of Starch in Coconut System)

[0123] The present example provides a method for detecting the swelling volume of starch in a coconut system, comprising the following steps:

[0124] First step: preparation of coconut system

[0125] Prepare the coconut juice system according to the ratio of 1:2 of coconut and distilled water, stir at 60°C for 10 min.

[0126] Second step: observation of swelling volume of starch in coconut juice system

[0127] (1) Measure the moisture content of starch with Mettler-Toledo moisture meter, and calculate the amount of modified starch with 8% dry basis.

[0128] (2) Weigh 100g of coconut juice in a beaker, add starch and disperse evenly, and place in a water bath for heating.

[0129] (3) Heat the water bath to 90°C, continuously stir at 300r / min for 10 min. Take out the beaker, cover it with plastic wrap, and put it back in the 90°C water bath. Hold the temperature for 20 min without stirring.

[0130] (4) After the starch is completely gelatinized, cool it in a 20°C water bath to room temperature, and supplement the water evaporated with coconut juice.

[0131] (5) Take 12.5g of starch paste in a 100mL measuring cylinder, add coconut juice to 100mL, so that the prepared concentration is 1g of starch dry basis net weight per 100mL of coconut juice. After 4°C cold storage for 72h, observe.

[0132] (6) In a dark environment, independent light source irradiation, the corresponding number of precipitated marks is the swelling volume V value.

[0133] (7) Record the swelling volume V value as 40.

[0134] Example 5 (Observation of Swelling Volume of Starch in Almond Juice System)

[0135] The present example provides a method for detecting the swelling volume of starch in an almond juice system, comprising the following steps:

[0136] First step: preparation of almond juice system

[0137] Prepare the almond juice system according to the ratio of 1:4 of almond juice and distilled water, stir at 60°C for 10 min.

[0138] Second step: Swelling volume observation of starch in almond milk system.

[0139] (1) The moisture content of starch was determined by Mettler-Toledo moisture analyzer, and the modified starch was calculated at 5% dry basis.

[0140] (2) 100g of almond milk was weighed in a beaker, starch was added and evenly dispersed, and heated in a water bath.

[0141] (3) The water bath was heated to 90°C, and continuous stirring was carried out at 300 r / min for 10 min. The beaker was taken out and covered with plastic wrap, and placed back in the 90°C water bath for 20 min without stirring.

[0142] (4) After the starch was completely gelatinized, it was cooled to room temperature in a 25°C water bath, and the evaporated water was supplemented with almond milk.

[0143] (5) 20g of starch paste was taken in a 100mL measuring cylinder, and almond milk was added to 100mL, so that the concentration of the prepared starch was 1g dry basis net weight per 100mL almond milk. After 4°C cold storage for 90h, it was observed.

[0144] (6) In a dark environment, an independent light source was used for illumination, and the corresponding number of precipitates was the swelling volume V value.

[0145] (7) The swelling volume V value was recorded as 35.

[0146] Examples 6-8: Swelling volume observation of starch in plant-based and milk mixed system

[0147] Example 6 (Swelling volume observation of starch in soy milk system)

[0148] The present example provides a method for detecting the swelling volume of starch in a soy milk system, comprising the following steps:

[0149] First step: Preparation of soy milk system

[0150] The soy milk system was prepared according to the ratio of soy milk to milk 1:5, 60°C, stirring for 10 min.

[0151] Second step: Swelling volume observation of starch in soy milk system.

[0152] (1) The moisture content of starch was determined by Mettler-Toledo moisture analyzer, and the modified starch was calculated at 5% dry basis.

[0153] (2) 100g of almond milk was weighed in a beaker, starch was added and evenly dispersed, and heated in a water bath.

[0154] (3) Water bath heating to 95℃, 400r / min continuous stirring for 10 min. Take out the beaker cover with fresh-keeping film, put back in 95℃ water bath, in the case of no stirring temperature 20 min.

[0155] (4) After starch gelatinization, cool to room temperature at 25℃ water bath, supplement the water loss with soy milk.

[0156] (5) Take 20g starch paste in 100mL measuring cylinder, supplement with soy milk to 100mL, so that the concentration prepared is 1g starch dry basis net weight / 100mL soy milk, observe after 4℃ refrigeration for 90h.

[0157] (6) In a dark environment, independent light source irradiation, the corresponding scale number of sediment is the swelling volume V value.

[0158] (7) Record the swelling volume V value as 28.

[0159] Example 7 (swelling volume observation of starch in coconut milk system)

[0160] The present example provides a method for detecting the swelling volume of starch in a coconut milk system, comprising the following steps:

[0161] First step: preparation of coconut milk system

[0162] Prepare the coconut juice system according to the ratio of 1:5 of coconut and milk, 60℃, stirring for 10 min.

[0163] Second step: swelling volume observation of starch in coconut milk system.

[0164] (1) Mettler-Toledo moisture meter to determine the moisture content of starch, calculate the 5% dry basis amount of modified starch.

[0165] (2) Weigh 100g of coconut milk in a beaker, add starch and disperse evenly, and place in a water bath.

[0166] (3) Water bath heating to 95℃, 400r / min continuous stirring for 10 min. Take out the beaker cover with fresh-keeping film, put back in 95℃ water bath, in the case of no stirring temperature 15 min.

[0167] (4) After starch gelatinization, cool to room temperature at 25℃ water bath, supplement the water loss with soy milk.

[0168] (5) Take 20g starch paste in 100mL measuring cylinder, supplement with soy milk to 100mL, so that the concentration prepared is 1g starch dry basis net weight / 100mL soy milk, observe after 4℃ refrigeration for 90h.

[0169] (6) In a dark environment, independent light source irradiation, the corresponding scale number of sediment is the swelling volume V value.

[0170] (7)Record the swelling volume V value as 35.

[0171] Example 8 (Swelling volume observation of starch in almond milk system)

[0172] The present example provides a method for detecting the swelling volume of starch in an almond milk system, comprising the following steps:

[0173] Step 1: Preparation of almond milk system

[0174] Prepare the almond milk system according to the ratio of 1:5 of almond juice to milk, 60℃, stir for 10 min.

[0175] Step 2: Swelling volume observation of starch in almond milk system

[0176] (1) Measure the moisture content of starch using a Mettler-Toledo moisture analyzer, and calculate the amount of modified starch at 5% dry basis.

[0177] (2) Weigh 100g of prepared almond milk in a beaker, add starch and disperse evenly, and place in a water bath for heating.

[0178] (3) Heat to 95℃ (water bath), continuously stir at 500 r / min for 10 min.

[0179] (4) Gelatinize the starch, take out the beaker and cover it with plastic wrap, and put it back in the 95℃ water bath for 20 min without stirring.

[0180] (5) After the starch is completely gelatinized, cool it in a 25℃ water bath to room temperature, and supplement the water evaporated with almond milk.

[0181] (6) Take 20g of starch paste (corresponding to 1g of dry starch) in a graduated cylinder, add almond milk to 100mL, so that the concentration of the prepared starch is 1g dry starch per 100mL almond milk, and observe after 90h of cold storage at 4℃.

[0182] (7) In a dark environment, use independent light source to illuminate, and the corresponding scale number of the precipitate is the swelling volume V value.

[0183] (8) Record the swelling volume V value as 35.

[0184] The method provided by the present application can be applied to the swelling volume observation of starch in various different systems, covering the main base systems of current yogurt production, including milk system, plant-based system and plant milk mixed system, etc., making the prediction of yogurt stability more comprehensive.

[0185] Example 9

[0186] This example provides cassava-derived starch swelling volume observation and stability evaluation in milk system, including the following steps:

[0187] First step, detection of cassava starch swelling volume in milk system.

[0188] (1) Mettler Toledo moisture meter to determine the moisture content of cassava starch, and calculate the amount of modified starch at 8% dry basis.

[0189] (2) Weigh 100g of milk in a beaker, add cassava starch (starch A), disperse evenly, and place in a water bath.

[0190] (3) Heat to 90°C (water bath), continuously stir at 300 r / min for 10 min.

[0191] (4) Make the starch paste, take out the beaker and cover it with plastic wrap, and put it back in the 90°C water bath. Hold the temperature for 15 min without stirring.

[0192] (5) After the starch is completely gelatinized, cool it to room temperature in a 5°C water bath, and supplement the water lost by evaporation with milk.

[0193] (6) Take 12.5g of starch paste in a graduated cylinder, add milk to 100mL, so that the concentration of the prepared starch is 1g dry basis per 100mL milk. After 4°C cold storage for 72h, observe.

[0194] (7) In a dark environment, use independent light source to illuminate, and the corresponding number of precipitates is the swelling volume V value.

[0195] (8) Record the swelling volume V value of cassava starch as 21.

[0196] Second step, yogurt fermentation.

[0197] Take 1L of milk, add 70g of sugar and 10g of starch, heat to 60°C, stir at 500rpm, and gelatinize for 15min. Homogenize at 60°C, control the secondary pressure at 30bar, and the total pressure at 170bar. Then, perform a pasteurization at 85°C for 10min at a speed of 400rpm. Cool down to 42°C, inoculate, ferment for 4h, measure the acidity, and break the emulsion when the acidity is above 70. Perform a second pasteurization, and immediately take out when the temperature rises to 85°C.

[0198] Third step, stability evaluation of yogurt.

[0199] (1) Yogurt viscosity detection: Under the condition of 25°C, use Brookfifield viscometer to test the viscosity value of yogurt. Record the viscosity value of yogurt as 10340.5cp.

[0200] (2) Yoghurt rheological detection (kinematic viscosity): The dynamic viscosity of the demulsified yoghurt was determined by using an Anton Paar rheometer. The yoghurt was sterilized and cooled to 25°C, and then poured into a sample cell and left to stand for 15 min. The CC27 clamp was used to perform the up-down speed experiment, the shear rate interval was set to 0-150 s -1 , the number of points was 24, the shear rate was 150 s -1 when reaching the maximum speed, and the shear rate interval was set to 150-0 s -1 , the number of points was 24, and the hysteresis loop formed by the up-down process was the thixotropic loop. The instrument was fitted with Hershel-Bulkley mode software for fitting analysis. The rheological viscosity of the yoghurt at 75 s -1 was recorded as 442.17 Pa.s; and the thixotropic loop area was 321.03 Pa / s.

[0201] (3) Yoghurt texture detection

[0202] The TA.XT plus texture analyzer was used to detect the consistency and hardness of the yoghurt. At 25°C, the yoghurt was poured into a cylindrical sample cup with a diameter of 50 mm, and left to stand for 15 min. The amount of each sample was 100-110 g (about 3 / 4 of the sample cup), the probe was AB / E (diameter 35 mm disc), the yoghurt consistency test module, the pre-test speed and test speed were both 1.00 mm / s, the return speed was 10 mm / s, the test down distance was 30.00 mm, and the preset homogeneity threshold was 0.52 g. The consistency of the yoghurt was recorded as 788.5; and the hardness of the yoghurt was 29.9.

[0203] Example 10

[0204] This example provides the observation of the swelling volume of the waxy rice-derived starch in the milk system and the stability evaluation, including the following steps:

[0205] Step 1: Detection of the swelling volume of waxy rice starch in the milk system.

[0206] (1) The Mettler-Toledo moisture meter was used to determine the moisture content of the waxy rice starch, and the modified starch was calculated at a dosage of 8% dry basis.

[0207] (2) 100 g of milk was weighed in a beaker, waxy rice starch (starch B) was added and dispersed uniformly, and then placed in a water bath for heating.

[0208] (3) Heat to 95°C (water bath), continuously stir at 500 r / min for 10 min.

[0209] (4) Gelatinize the starch, take out the beaker, cover it with plastic wrap, and put it back in the 95°C water bath for 20 min without stirring.

[0210] (5) After the starch paste is completely gelatinized, it is cooled to room temperature in a water bath at 25°C, and milk is added to make up for the water evaporated.

[0211] (6) Take 12.5 g of starch paste in a measuring cylinder, add milk to 100 mL, so that the concentration prepared is 1 g of starch dry basis net weight per 100 mL of milk, and observe after 90 h of standing at 4°C.

[0212] (7) In a dark environment, an independent light source is irradiated, and the corresponding number of precipitates is the swelling volume V value.

[0213] (8) Record the swelling volume V value of waxy rice starch as 30.

[0214] Second step, yogurt fermentation. (For specific test parameters and steps, refer to Example 9)

[0215] Third step, evaluation of yogurt stability. (For specific test parameters and steps, refer to Example 9)

[0216] (1) Yogurt viscosity detection: Under the condition of 25°C, Brookfifield viscometer is used to test the viscosity value of yogurt. Record the viscosity value of yogurt as 11465 cp.

[0217] (2) Yogurt rheological detection (kinematic viscosity): Anton Paar rheometer is used to determine the dynamic viscosity of the demulsified yogurt. Record the rheological viscosity of yogurt at 75 s -1 as 507.27 Pa.s; Thixotropic ring area is 744.57 Pa / s.

[0218] (3) Yogurt texture detection: Record the consistency of yogurt as 1138.036; the hardness of yogurt is 41.715.

[0219] Example 11

[0220] This example provides observation of the swelling volume of waxy corn-derived starch in a milk system and stability evaluation, including the following steps:

[0221] First step, detection of the swelling volume of corn starch in a milk system.

[0222] (1) Mettler-Toledo moisture meter is used to determine the moisture content of corn starch, and 8% dry basis of modified starch is calculated.

[0223] (2) Weigh 100 g of milk in a beaker, add corn starch (starch C), disperse uniformly, and place in a water bath.

[0224] (3) Heat to 95°C (water bath), continuously stir at 400 r / min for 10 min.

[0225] (4) Make starch gelatinization, take out the beaker cover with plastic wrap, put back in 95°C water bath, hold temperature for 20 min without stirring.

[0226] (5) After starch gelatinization, cool to room temperature in 25°C water bath, and supplement evaporated water with milk.

[0227] (6) Take 12.5 g of starch paste in a graduated cylinder, add milk to 100 mL, so that the concentration prepared is 1 g of starch dry basis net weight per 100 mL of milk, and observe after 72 h of cold storage at 4°C.

[0228] (7) In a dark environment, independent light source irradiation, the corresponding number of precipitates is the swelling volume V value.

[0229] (8) Record the swelling volume V value of waxy rice starch as 31.

[0230] Second step, yogurt fermentation. (Specific test parameters and steps refer to Example 9)

[0231] Third step, yogurt stability evaluation. (Specific test parameters and steps refer to Example 9)

[0232] (1) Yogurt viscosity detection: record the yogurt viscosity value as 17255 cp.

[0233] (2) Yogurt rheological detection (kinematic viscosity): record the yogurt rheological viscosity at 75 s -1 516.28 Pa.s; thixotropic ring area is 1346.3 Pa / s.

[0234] (3) Yogurt texture detection: use TAXT plus texture analyzer to detect yogurt consistency and hardness. Record the yogurt consistency as 1306.446; and the yogurt hardness as 48.594.

[0235] The test results of Examples 9-11 are as follows:

[0236] Table 2 Swelling volume and yogurt stability results of starches from different sources

[0237]

[0238] The results prove that the starch swelling volume detection method is suitable for the measurement of starches from different sources in the milk system, and the swelling volume size can indirectly predict the stability of yogurt. The swelling volumes of the three sources of starches are different, with waxy corn starch being greater than waxy rice starch and greater than cassava starch, and the static viscosity, rheological viscosity, hysteresis area, consistency, and hardness of the yogurt also show the same pattern. This is because starch plays a role in thickening and viscosity in yogurt. With the increase of swelling volume, the degree of starch gelatinization is better, the water absorption and swelling are better, the thickening and viscosity effects are better, and the structure support is stronger, so the hardness also shows the same trend as the swelling volume. The hysteresis area represents the degree of recovery of the yogurt structure after shearing. The greater the hysteresis area, the slower the recovery of the yogurt structure. The hysteresis areas of the three starches conform to the change trend of the swelling volume, which is mainly because the larger the starch swelling volume, the greater the water absorption and swelling of the particles, the more easily broken by shearing, the stronger the destructiveness to the yogurt structure, and the more difficult the structure recovery. The detection data of the three different sources of starches conform to the change trend of the starch swelling volume, which can indirectly reflect the stability of the yogurt. Therefore, it can be seen that the detection method of the present application has high accuracy, simple measurement, and wide adaptability.

[0239] Example 12

[0240] This example provides observation of the swelling volume of hydroxypropyl starch in the milk system and stability evaluation, including the following steps:

[0241] First, detection of the swelling volume of hydroxypropyl starch in the milk system

[0242] (1) Measure the moisture content of hydroxypropyl starch with a Mettler-Toledo moisture meter, and calculate the amount of modified starch at 2% dry basis.

[0243] (2) Weigh 100g of milk in a beaker, add hydroxypropyl starch (starch D), disperse uniformly, and place in a water bath.

[0244] (3) Heat to 95℃ (water bath), continuously stir at 500r / min for 10min.

[0245] (4) Gelatinize the starch, take out the beaker, cover with plastic wrap, and place back in the 95℃ water bath for 20min without stirring.

[0246] (5) After the starch is completely gelatinized, cool it to room temperature in a 25℃ water bath, and supplement the water loss with milk.

[0247] (6) Take 50g of starch paste in a graduated cylinder, add milk to 100mL, so that the concentration of the prepared starch is 1g dry basis net weight per 100mL milk, and observe after 90h of cold storage at 4℃.

[0248] (7) In the dark environment, the corresponding number of precipitates is the swelling volume V value under the irradiation of independent light source.

[0249] (8) The swelling volume V value of hydroxypropyl starch is recorded as 16.

[0250] Second step, yogurt fermentation.

[0251] Take 1L of milk, add 70g of sugar and 10g of starch, heat to 60℃, stir at 500rpm, and melt for 15min. Homogenize at 60℃, control the secondary pressure at 30bar, and the total pressure at 170bar. Then, perform 85℃ pasteurization for 10min at 400rpm. Cool to 42℃, inoculate, ferment for 4h, measure the acidity, and break the emulsion when the acidity is above 70. Perform secondary pasteurization, and immediately take out when the temperature rises to 85℃.

[0252] Third step, yogurt stability evaluation.

[0253] (1) Yogurt water holding rate detection: accurately weigh 10g of yogurt sample and put it into a 15mL centrifuge tube. Centrifuge at 6000r / min for 15min at room temperature. Pour out the supernatant and absorb the residual moisture with a water absorption paper. Weigh and calculate the mass of the precipitate and the centrifuge tube to finally calculate the value of the water holding capacity WHC. WHC(%)=(mass of precipitate in centrifuge tube / sample mass)×100. Record the yogurt water holding rate as 74.29%.

[0254] (2) Yogurt texture detection

[0255] Use TAXT plus texture analyzer to detect the viscoelasticity of yogurt. At 25℃, pour the yogurt into a cylindrical sample cup with a diameter of 50mm, and let it stand for 15min. Each time the sample amount is 100-110g (about 3 / 4 of the sample cup), the probe is AB / E (diameter 35mm disc), the yogurt consistency test module, the pre-test speed and test speed are both 1.00mm / s, the return speed is 10mm / s, the test compression distance is 30.00mm, and the preset homogeneity threshold is 0.52g. Record the yogurt consistency as 910.55; the yogurt viscoelasticity as -35.67.

[0256] Example 13

[0257] This example provides the swelling volume observation and stability evaluation of acetylated starch in a milk system, including the following steps:

[0258] (Specific test steps are the same as in Example 5)

[0259] First step, detection of the swelling volume of acetylated starch in a milk system.

[0260] (1) The moisture content of acetylated starch was determined by a Mettler-Toledo moisture analyzer, and the amount of modified starch was calculated at 2% dry basis.

[0261] (2) 100 g of milk was weighed in a beaker, acetylated starch (starch E) was added and evenly dispersed, and then placed in a water bath for heating.

[0262] (3) Heat to 95°C (water bath), continuously stir at 500 r / min for 5 min.

[0263] (4) Gelatinize the starch, take out the beaker, cover it with plastic wrap, and put it back in the 95°C water bath. Hold the temperature for 15 min without stirring.

[0264] (5) After the starch is completely gelatinized, cool it to room temperature in a 20°C water bath, and supplement the evaporated water with milk.

[0265] (6) Take 50 g of starch paste in a graduated cylinder, add milk to 100 mL, so that the concentration of the prepared starch is 1 g dry basis net weight per 100 mL of milk. After 4°C refrigeration for 90 h, observe.

[0266] (7) In a dark environment, use an independent light source to illuminate, and the corresponding number of precipitates is the swelling volume V value.

[0267] (8) Record the swelling volume V value of acetylated starch as 22.

[0268] Second step, yogurt fermentation. (For specific test parameters and steps, refer to Example 12)

[0269] Third step, evaluation of yogurt stability. (For specific test parameters and steps, refer to Example 12)

[0270] (1) Yogurt water holding capacity detection. Record the yogurt water holding capacity as 75.66%.

[0271] (2) Yogurt texture detection

[0272] Use TAXT plus texture analyzer to detect the viscoelasticity and consistency of yogurt. Record the yogurt consistency as 1145.90; and the yogurt viscoelasticity as -46.

[0273] Example 14

[0274] This example provides the observation of the swelling volume of physical starch in a milk system and the evaluation of its stability, including the following steps:

[0275] First step, detection of the swelling volume of physical starch in a milk system.

[0276] (1) The moisture content of physical modified starch was determined by a Mettler-Toledo moisture analyzer, and the amount of modified starch was calculated at 5% dry basis.

[0277] (2) Use a beaker to weigh 100 g of milk, add physically modified starch (starch F), disperse evenly, and place in a water bath for heating.

[0278] (3) Heat to 95°C (water bath), continuously stir at 500 r / min for 10 min.

[0279] (4) Gelatinize the starch, take out the beaker, cover with plastic wrap, and put back in the 95°C water bath. Hold the temperature for 20 min without stirring.

[0280] (5) After the starch is completely gelatinized, cool to room temperature in a 25°C water bath, and supplement the water lost by evaporation with milk.

[0281] (6) Take 20 g of starch paste in a graduated cylinder, add milk to 100 mL, so that the concentration prepared is 1 g of starch dry basis net weight per 100 mL of milk, and observe after 90 h of cold storage at 4°C.

[0282] (7) In a dark environment, use an independent light source to irradiate, and the corresponding number of precipitates is the swelling volume V value.

[0283] (8) Record the physical starch swelling volume V value as 29.

[0284] Second step, yogurt fermentation. (Refer to Example 12 for specific test parameters and steps)

[0285] Third step, evaluation of yogurt stability. (Refer to Example 12 for specific test parameters and steps)

[0286] (1) Yogurt water holding capacity detection. Record the yogurt water holding capacity as 77.71%.

[0287] (2) Yogurt texture detection

[0288] Use TAXT plus texture analyzer to detect the viscoelasticity and consistency of yogurt. Record the yogurt consistency as 1078.639; and the yogurt viscoelasticity as -51.128.

[0289] The test results of Examples 12-14 are as follows:

[0290] Table 3 Swelling volume of starch and yogurt stability results under different treatment methods

[0291]

[0292] The results prove that the starch swelling volume detection method is suitable for the measurement of different treated (chemically and physically modified) starches in milk system, and the swelling volume size can indirectly predict the stability of yogurt. The swelling volumes of three different treated starches are different, and the swelling volume of physically modified starch is larger than that of acetylated starch, which is larger than that of hydroxypropylated starch. The water holding rate, consistency and viscoelasticity of yogurt also show the same rule, because after heating, the starch absorbs water and swells, the swelling volume increases, and the water holding rate increases. The better the starch gelatinization degree, the better the thickening and viscosity effect, and the higher the consistency. The stronger the gelatinization degree, the stronger the viscoelasticity of yogurt texture. The detection data of three different treated starches are consistent with the change trend of starch swelling volume. And the change trend of starch swelling volume and the detection indexes of yogurt also show corresponding change rule. Therefore, it can be seen that the detection method of the present application can detect the gelatinization degree of starch, thereby indirectly predicting the stability of yogurt, and has the characteristics of high accuracy, simple measurement, wide adaptability and the like.

[0293] Although the present application has been described in detail above with general description and specific embodiments, some modifications or improvements can be made on the basis of the present application, which is obvious to those skilled in the art. Therefore, these modifications or improvements made on the basis of not deviating from the spirit of the present application, all belong to the scope of protection claimed by the present application.

Claims

1. A method for the detection of starch swelling volume simultaneously applicable in aqueous, emulsion, plant-based systems, characterized in that, The method comprises: (1) mixing the to-be-tested starch with a solvent system to obtain a mixed solution; the content of the to-be-tested starch in the mixed solution is 2-8 wt% based on the dry basis of the to-be-tested starch; (2) performing a gelatinization reaction on the to-be-tested starch in the solvent system to obtain a starch paste; the gelatinization reaction comprises: performing a gelatinization reaction for 5-10 min under stirring, and then performing a gelatinization reaction for 15-20 min without stirring; the stirring is performed at a rotation speed of 300-500 r / min; the gelatinization reaction is performed under water bath conditions at a temperature of 90-95 ℃; (3) performing cold storage and standing on the starch paste, and then measuring the volume of the starch precipitate; the cold storage and standing is performed at a temperature of-1-8 ℃. The starch is a starch used as a raw material of yogurt.

2. The method for detecting the swelling volume of starch according to claim 1, characterized in that, The cold storage and standing is performed for 60-90 h.

3. The method of claim 1 or 2, wherein The cold storage and standing is performed at a temperature of 2-4 ℃.

4. The method of claim 1 or 2, wherein The starch is selected from cassava starch, waxy corn starch, or acetylated starch, hydroxypropylated starch, and combinations thereof.

5. The method of claim 1 or 2, wherein After the gelatinization reaction, a portion of the starch paste is taken into a measuring cylinder, so that the dry basis mass of the to-be-tested starch in the taken starch paste is 1 g, and then the solvent system is supplemented to 100 mL for cold storage and standing.

6. The method of claim 1 or 2, wherein The volume of the starch precipitate is observed under independent light source irradiation in a dark environment.

7. Use of the method for detecting the swelling volume of starch according to any one of claims 1-6 in any one of the following aspects: (1) preliminary screening of starch as a raw material of yogurt; (2) determination of the gelatinization temperature of starch in the development process of yogurt products; (3) evaluation of the stability of yogurt.

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