阅读说明：本技术 一种酸奶用乙酰化二淀粉磷酸酯及其制备方法 (Acetylated distarch phosphate for yoghourt and preparation method thereof ) 是由 佟毅 李义 朱雯雯 洪雁 张秀荣 张连慧 顾娟 惠滢 邹迪 于 2020-06-09 设计创作，主要内容包括：本发明涉及一种酸奶用乙酰化二淀粉磷酸酯及其制备方法,属于变性淀粉制备领域。将淀粉加水配制为淀粉乳,调节淀粉乳液pH值,搅拌升温,加入三偏磷酸钠,交联反应1～3h,待交联反应结束后,调节淀粉乳的pH值,水浴温度为20～30℃,滴加乙酸酐,酯化总时长为3～5h,用酸性溶液对反应液进行中和,洗涤、干燥、粉碎筛分。有益效果在于：通过交联和酯化两种变性手段,使其具有较高的黏度、较好的膨润力、较佳的冻融稳定性和耐酸稳定性,较强的抗剪切能力,以上性质使其最适应用于酸奶中,能够显著增加酸奶的表观黏度、持水力以及储藏稳定性,改良酸奶的感官品质,明显改善酸奶产品的流变学特性,降低温度及频率变化对凝胶强度的影响。(The invention relates to acetylated distarch phosphate for yoghourt and a preparation method thereof, belonging to the field of modified starch preparation. Adding water into starch to prepare starch milk, adjusting the pH value of the starch milk, stirring and heating, adding sodium trimetaphosphate, carrying out crosslinking reaction for 1-3 h, adjusting the pH value of the starch milk after the crosslinking reaction is finished, controlling the water bath temperature to be 20-30 ℃, dropwise adding acetic anhydride, carrying out esterification for 3-5 h, neutralizing the reaction solution with an acid solution, washing, drying, crushing and screening. Has the advantages that: the yogurt has the advantages that the yogurt has high viscosity, high swelling power, high freeze-thaw stability, high acid resistance and high shear resistance through two denaturation means of crosslinking and esterification, is most suitable for yogurt due to the properties, can remarkably increase the apparent viscosity, water holding capacity and storage stability of yogurt, improves the sensory quality of yogurt, obviously improves the rheological property of yogurt products, and reduces the influence of temperature and frequency change on gel strength.)

1. An acetylated distarch phosphate for yoghurt, which is characterized by being obtained by the following steps:

adding water into starch to prepare 30-50% (w/w, d.b) of starch milk, adjusting the pH value of the starch milk to 10.0-11.0, stirring and heating to 40-50 ℃, adding sodium trimetaphosphate accounting for 0.6-1.4% of the dry mass of the starch, carrying out crosslinking reaction for 1-3 h, adjusting the pH value of the starch milk to 8.0-8.5 after the crosslinking reaction is finished, carrying out water bath at 20-30 ℃, dropwise adding acetic anhydride accounting for 5.0-6.0% of the dry mass of the starch, carrying out esterification for 3-5 h, neutralizing the reaction solution with an acid solution after the reaction is finished, washing, drying, crushing and screening to obtain the acetylated distarch phosphate for the yogurt.

2. The acetylated distarch phosphate according to claim 1, wherein the acetylated distarch phosphate comprises: the content range of acetyl of the acetylated distarch phosphate for the yoghourt is 1.65-1.75%, and the sedimentation volume range is 2-4 mL.

3. The acetylated distarch phosphate according to claim 1, wherein the acetylated distarch phosphate comprises: the viscosity of the acetylated distarch phosphate for the yoghourt is reduced by less than 10% or increased to some extent in a neutral system with the pH value of 7 and an acid system with the pH value of 3.

4. The acetylated distarch phosphate according to claim 1, wherein the acetylated distarch phosphate comprises: the acetylated distarch phosphate for the yoghourt has the consistency coefficient K ranging from 25 Pa s to 35Pa s and the fluid index n less than 0.5.

5. The acetylated distarch phosphate according to claim 1, wherein the acetylated distarch phosphate comprises: the homogenization temperature of the acetylated distarch phosphate for the yoghourt in the yoghourt preparation process is 60 ℃, namely the gelatinization temperature is in the range of 60-70 ℃; in a neutral system with the pH value of 7, the highest viscosity of the starch paste in the temperature rise stage is the peak viscosity, and the final viscosity in the heat preservation process at 50 ℃ is the final viscosity.

6. The acetylated distarch phosphate according to claim 1, wherein the acetylated distarch phosphate comprises: the acetylated distarch phosphate for the yoghourt has better freeze-thaw stability, and the water precipitation rate after 5 times of freeze-thaw cycles is within the range of 10-25%.

7. A preparation method of acetylated distarch phosphate for yoghourt is characterized in that: comprises the following steps:

adding water into starch to prepare 30-50% (w/w, d.b) of starch milk, adjusting the pH value of the starch milk to 10.0-11.0, stirring and heating to 40-50 ℃, adding sodium trimetaphosphate accounting for 0.6-1.4% of the dry mass of the starch, carrying out crosslinking reaction for 1-3 h, adjusting the pH value of the starch milk to 8.0-8.5 after the crosslinking reaction is finished, carrying out water bath at 20-30 ℃, dropwise adding acetic anhydride accounting for 5.0-6.0% of the dry mass of the starch, carrying out esterification for 3-5 h, neutralizing the reaction solution with an acid solution after the reaction is finished, washing, drying, crushing and screening to obtain the acetylated distarch phosphate for the yogurt.

Technical Field

The invention belongs to the technical field of modified starch preparation and application, and particularly relates to characteristics, modification degree and a preparation method of acetylated distarch phosphate modified starch for yoghourt.

Background

The yoghourt is more and more favored by consumers due to the unique flavor and health value, particularly, in recent years, the consumption of the stirring type yoghourt is increased, the market competition is strong, and therefore, the improvement of the thickness, the texture, the stability and the mouthfeel of the product is the aim pursued by various yoghourt manufacturers.

In the process of fermenting and curding the yogurt, the denatured whey protein is filled in the casein matrix and forms a complex spatial structure with milk fat spheres, and the arrangement of the spatial structure macroscopically influences the milk fat feeling, so that the sensory experience is influenced. When the space structure is damaged by external factors such as temperature change, shear enhancement, pH value reduction and the like, the system has quality defects such as phase separation, whey precipitation, viscosity reduction and the like, so that the stability of the yogurt structure is very important for quality improvement. Within a certain range, the influence of the viscosity on the sensory quality of the yoghourt is positively correlated. Therefore, thickening stabilizers are often added to the yogurt to increase the yogurt consistency, improve the product texture, and increase the total solid content and stability of the system, thereby improving the yogurt consumption quality and consumer acceptance.

Starch is a carbohydrate with wide source and low price. During the curd process, starch is embedded in the casein network as an inactive filler and increases the milk protein concentration by absorbing water swelling in the continuous phase, thereby increasing the gel strength. The natural starch is subjected to appropriate physical, chemical or biological modification, so that the thickening property of the starch can be improved, and the acid resistance, heat resistance, shear resistance and other properties of the starch can be improved, so that the starch has more excellent application performance in the yogurt.

Disclosure of Invention

The invention provides acetylated distarch phosphate for yoghourt and a preparation method thereof, aiming at enhancing the curd structure of the yoghourt, increasing the viscosity and improving the water holding capacity of the yoghourt.

The technical scheme adopted by the invention is as follows: is obtained by the following steps:

adding water into starch to prepare 30-50% (w/w, d.b) of starch milk, adjusting the pH value of the starch milk to 10.0-11.0, stirring and heating to 40-50 ℃, adding sodium trimetaphosphate accounting for 0.6-1.4% of the dry mass of the starch, carrying out crosslinking reaction for 1-3 h, adjusting the pH value of the starch milk to 8.0-8.5 after the crosslinking reaction is finished, carrying out water bath at 20-30 ℃, dropwise adding acetic anhydride accounting for 5.0-6.0% of the dry mass of the starch, carrying out esterification for 3-5 h, neutralizing the reaction solution with an acid solution after the reaction is finished, washing, drying, crushing and screening to obtain the acetylated distarch phosphate for the yogurt.

The acetyl content range of the acetylated distarch phosphate for the yoghourt is 1.65-1.75%, and the sedimentation volume range is 2-4 mL.

The viscosity of the acetylated distarch phosphate for the yoghourt is reduced by less than 10% or increased to some extent in a neutral system with the pH value of 7 and an acid system with the pH value of 3.

The acetylated distarch phosphate for the yoghourt has the consistency coefficient K ranging from 25 Pa s to 35Pa s and the fluid index n less than 0.5.

The homogenization temperature of the acetylated distarch phosphate for the yoghourt in the yoghourt preparation process is 60 ℃, namely the gelatinization temperature is in the range of 60-70 ℃; in a neutral system with the pH value of 7, the highest viscosity of the starch paste in the temperature rise stage is the peak viscosity, and the final viscosity in the heat preservation process at 50 ℃ is the final viscosity.

The acetylated distarch phosphate for the yoghourt has better freeze-thaw stability, and the water precipitation rate after 5 times of freeze-thaw cycles is within the range of 10-25%.

A preparation method of acetylated distarch phosphate for yoghourt comprises the following steps:

adding water into starch to prepare 30-50% (w/w, d.b) of starch milk, adjusting the pH value of the starch milk to 10.0-11.0, stirring and heating to 40-50 ℃, adding sodium trimetaphosphate accounting for 0.6-1.4% of the dry mass of the starch, carrying out crosslinking reaction for 1-3 h, adjusting the pH value of the starch milk to 8.0-8.5 after the crosslinking reaction is finished, carrying out water bath at 20-30 ℃, dropwise adding acetic anhydride accounting for 5.0-6.0% of the dry mass of the starch, carrying out esterification for 3-5 h, neutralizing the reaction solution with an acid solution after the reaction is finished, washing, drying, crushing and screening to obtain the acetylated distarch phosphate for the yogurt.

The invention provides the requirements on the properties of the acetylated distarch phosphate composite modified starch for the yoghourt and the modification degree thereof. The crosslinking denaturation promoting particles have stable structure and good heat resistance stability, shear resistance and the like, the acetylation denaturation increases the viscosity and water holding capacity of the starch paste, and the composite denaturation can integrate the advantages of crosslinking and esterification and make up for the disadvantage of single modification. Therefore, the acetylated distarch phosphate is added into the yoghourt as the esterified cross-linked composite modified starch, which can enhance the curd structure of the yoghourt, increase the viscosity and improve the water holding capacity of the yoghourt. Meanwhile, due to the unique structure, the flavor substances can be contained in the yogurt, so that the thick feeling and aftertaste of the yogurt are increased.

The invention has the beneficial effects that: provides the requirements of the property and the modification degree of the acetylated distarch phosphate for the yoghourt and provides the preparation method thereof. The composite modified starch has high viscosity, high swelling power, high freeze-thaw stability, high acid resistance and high shear resistance through two modification means of crosslinking and esterification, is most suitable for being applied to the yoghourt due to the properties, can obviously increase the apparent viscosity, water holding capacity and storage stability of the yoghourt, improves the sensory quality of the yoghourt, obviously improves the rheological property of the yoghourt product, and reduces the influence of temperature and frequency change on the gel strength.

Drawings

FIG. 1 is a graph of the effect of pH on the viscosity of acetylated distarch phosphate for yogurt.

Detailed Description

Embodiments of the present invention will be described in detail below with reference to examples, but those skilled in the art will appreciate that the following examples are only illustrative of the present invention and should not be construed as limiting the scope of the present invention.