Lotus root texture analysis and evaluation method

Abstract

The invention belongs to the field of fruit and vegetable quality analysis and detection, and discloses a lotus root texture analysis and evaluation method. The method comprises the following steps: collecting lotus root samples of different varieties; washing the sample, removing lotus root skin and nodes, and slicing to obtain slices; putting a piece of weighing paper under the thin sheet, and putting the thin sheet into a microwave oven for heating; taking out the heated slices, cooling to room temperature, and cutting into blocks; measuring the block by using a TPA mode of a texture analyzer to obtain texture data of the block; organizing and standardizing the texture data of the blocks, and performing fitting by using a first-level dynamic model to obtain first-level dynamic fitting parameter data; carrying out secondary fitting on the primary dynamic fitting parameter data to obtain secondary fitting parameter data; and judging the texture of the lotus root according to the quadratic fitting parameter data. The method provided by the invention is constructed based on a texture feature change kinetic model in a microwave field, and provides reference for edible quality identification and precise processing of typical crisp lotus roots.

Description

Technical Field

[0001] The invention belongs to the field of fruit and vegetable quality analysis and detection, and more specifically, relates to a lotus root texture analysis and evaluation method. Background Art

[0002] Lotus root (Nelumbo nucifera Gaertn.) is an aquatic vegetable, the main components of which are carbohydrates (including starch and dietary fiber), protein, minerals, vitamins, etc. Among them, dietary fiber has the functions of lowering cholesterol, preventing and treating constipation, diabetes and cancer. Lotus root contains a large number of medicinal ingredients. At present, alkaloids, triterpenes, flavonoids, polysaccharides and polyphenols have been separated from various parts of lotus root, which have antioxidant, anti-cancer, anti-viral, weight loss, lowering blood lipids, lowering blood sugar, lowering cholesterol, clearing away heat and detoxification, and antibacterial and anti-inflammatory effects. It has a delicious flavor and a sweet taste, and is deeply loved by consumers.

[0003] As the specialty aquatic vegetable with the largest planting area in my country, the annual output of lotus root exceeds 10 million tons, among which Hubei Province ranks first in the country in terms of cultivation area. There are many varieties of lotus roots, including local varieties, artificially cultivated varieties and wild varieties. There are great differences in the cultivation conditions, appearance, texture, taste and other aspects of each variety of lotus root. The texture of the same variety of lotus root at different harvesting periods also varies. According to the taste and texture after cooking, lotus roots can be divided into powdery type and crispy type. The two types of lotus roots with different textures are different in fresh consumption and food processing, such as stir-frying crisp lotus roots and making soup with powdery lotus roots. Therefore, there is a need for texture analysis and identification of lotus roots in all aspects of cultivation, scientific research, processing and consumption.

[0004] At present, the crispy texture of lotus root is often judged by sensory experience or distinguished by measuring the physicochemical composition and texture characteristics of fresh lotus root. However, in modern processing, empirical methods often cannot accurately sort lotus root raw materials of different textures, sensory evaluation is subjective, and the determination of physicochemical components is cumbersome and complicated. The texture characteristics of fresh lotus root cannot well reflect the texture characteristics after processing, resulting in unstable product quality. At present, there is still a lack of methods to distinguish and quantify the crispy texture of lotus root. Therefore, it is of great significance to construct a new analytical evaluation method for lotus root texture. Summary of the invention

[0005] The purpose of the present invention is to propose a method for analyzing and evaluating the texture of lotus root in view of the deficiencies of the prior art. The method of the present invention is based on a dynamic model of texture characteristic changes in a microwave field, and provides a reference for the edible quality identification and precise processing of typical crunchy lotus roots.

[0006] In order to achieve the above object, the present invention provides a method for analyzing and evaluating lotus root texture, the method comprising the following steps:

[0007] S1: Collect lotus root samples of different varieties;

[0008] S2: washing the sample of step S1, removing the lotus root skin and nodes, and slicing to obtain thin slices;

[0009] S3: Place a weighing paper under the sheet and heat it in a microwave oven;

[0010] S4: After the slice is heated, it is taken out and cooled to room temperature (in the present invention, the room temperature is 15-35° C.), and cut into blocks;

[0011] S5: measuring the block using a texture analyzer TPA mode to obtain texture data of the block;

[0012] S6: sorting and standardizing the texture data of the block, and fitting it using a first-order kinetic model to obtain first-order kinetic fitting parameter data;

[0013] S7: performing a second-order fitting on the first-order kinetic fitting parameter data by formula (1) to obtain second-order fitting parameter data; and determining the texture of the lotus root according to the second-order fitting parameter data;

[0014] The formula (1) is ln(-k1)=ax+b, where:

[0015] k1 is the first-order kinetic fitting parameter data;

[0016] x is the firepower value of the microwave oven corresponding to the heating power of the microwave oven.

[0017] According to the present invention, preferably, in step S2, the middle section of the lotus root 1.5-2.5 cm away from the lotus root node is selected for slicing.

[0018] According to the present invention, preferably, the thickness of the sheet is 4.5-5.5 mm.

[0019] According to the present invention, preferably, in step S3, the heating power of the microwave oven is 200-600w, and the heating time is 0-85s.

[0020] According to the present invention, preferably, in step S3, one slice is placed in the microwave oven for heating at a time. In the present invention, it should be noted that there will be residual heat after heating in the microwave oven, and subsequent slice samples should be heated after the microwave oven cools down to room temperature.

[0021] In the present invention, as a preferred embodiment, one slice is placed in the middle area of ​​the microwave oven for heating.

[0022] In the present invention, 240w corresponds to the microwave oven p30 firepower; 320w corresponds to the microwave oven p40 firepower; 400w corresponds to the microwave oven p50 firepower; 480w corresponds to the microwave oven p60 firepower; 560w corresponds to the microwave oven p70 firepower.

[0023] According to the present invention, preferably, in the step S4, the lotus root flesh at the edge of the lotus root with holes is taken and cut into the blocks.

[0024] According to the present invention, preferably, the size of the block is (0.8-1.2) cm×(0.8-1.2) cm×(0.45-0.55) cm.

[0025] According to the present invention, preferably, in step S5, the operating parameters of the texture analyzer include: 900-1000N sensing element, P36R probe, test speed 55-65mm / min, test distance 0.8-1.2cm, trigger force 0.4-0.6N, deformation amount 30-40%.

[0026] According to the present invention, preferably, the texture data of the block includes: measurement time and hardness of the block.

[0027] According to the present invention, preferably, the quadratic fitting parameter data is k2;

[0028] When k2<0.020, the lotus root is defined as a brittle lotus root;

[0029] When 0.020<k2<0.025, the lotus root is defined as both soft and crispy;

[0030] When k2>0.025, the lotus root is defined as pink lotus root.

[0031] The beneficial effects of the technical solution of the present invention are as follows:

[0032] The lotus root texture analysis and evaluation method of the present invention is constructed based on a dynamic model of texture characteristic changes in a microwave field. The present invention can scientifically, objectively, quickly and conveniently evaluate the texture of different varieties of lotus roots based on a microwave dynamic model, provide quantifiable standards, and is suitable for evaluating the texture changes of different varieties of lotus roots and different varieties of lotus roots in a variety of conventional processing processes and predicting the texture of their finished products, forming a lotus root powder and crispness characteristic evaluation method, and providing a reference for the edible quality identification and precise processing of lotus roots with typical powder and crispness characteristics.

[0033] The method of the present invention can be widely used to evaluate the texture differences of fruits and vegetables at different harvesting periods and storage and processing conditions, explore the range of processing conditions suitable for different varieties of fruits and vegetables, reasonably predict product texture, and provide a reference for fruit and vegetable breeding, cultivation, harvesting, storage, processing, etc.

[0034] Other features and advantages of the present invention will be described in detail in the following detailed description. DETAILED DESCRIPTION

[0035] The preferred embodiments of the present invention will be described in more detail below. Although the preferred embodiments of the present invention are described below, it should be understood that the present invention can be implemented in various forms and should not be limited by the embodiments set forth herein. On the contrary, these embodiments are provided to make the present invention more thorough and complete, and to fully convey the scope of the present invention to those skilled in the art.

[0036] Example 1

[0037] This embodiment provides a method for analyzing and evaluating lotus root texture, the method comprising the following steps:

[0038] S1: Collect lotus root samples of six varieties, namely, E-Lian No. 5, E-Lian No. 6, Wuzhi No. 2, Xinsanwu, Huaqilian, and Mianchengou (select those with complete structure, similar thickness, freshness and no damage);

[0039] S2: Wash the samples in step S1 with running water, remove the lotus root skin and lotus root nodes, and then select the middle part of the lotus root 2 cm away from the lotus root node for slicing to obtain six varieties of thin slices with a uniform thickness of 5 mm;

[0040] S3: Place a weighing paper under the slices, and heat the slices one at a time in the middle of the microwave oven; set the heating power and time of the microwave oven to p30 (240w), p40 (320w), p50 (400w), p60 (480w), p70 (560w) and 0, 20s, 40s, 60s, 80s respectively;

[0041] S4: After the slice is heated, take it out and cool it to room temperature, take the lotus root meat at the edge of the slice with holes, and cut it into blocks with a size of 1 cm×1 cm×0.5 cm;

[0042] S5: measuring the block using a texture analyzer TPA mode to obtain texture data of the block;

[0043] The operating parameters of the texture analyzer include: 1000N induction element, P36R probe, test speed 60mm / min, test distance 1cm, trigger force 0.5N, deformation amount 35%.

[0044] The texture data of the block include: measurement time and hardness of the block.

[0045] S6: sorting and standardizing the texture data of the block, with the abscissa being the measurement time and the ordinate being the hardness of the block, and fitting using a first-order kinetic model to obtain first-order kinetic fitting parameter data, as shown in Table 1;

[0046] Table 1 First-order kinetic fitting parameters of hardness change of lotus root slices under different microwave powers

[0047]

[0048]

[0049] As shown in Table 1, the dynamic characteristic parameters k1, R1 of the hardness of six varieties of lotus roots under different microwave powers 2 All of them were greater than 0.93, indicating that the first-order kinetic model fitted well.

[0050] S7: The first-order kinetic fitting parameters k of each variety of lotus root under five groups of microwave powers 1-1 , k 1-2 , k 1-3 , k 1-4 , k 1-5 (For example: for Elian No. 5, k 1-1 =-0.00862, k 1-2 =-0.01093, k 1-3 =-0.01215, k 1-4 =-0.01309, k 1-5 =-0.02010) perform quadratic fitting through formula (1) to obtain quadratic fitting parameter data; determine the texture of lotus root according to the quadratic fitting parameter data;

[0051] The formula (1) is ln(-k1)=ax+b, where:

[0052] k1 is the first-order kinetic fitting parameter k for each variety of lotus root under five groups of microwave powers 1-1 , k 1-2 , k 1-3 , k 1-4 , k 1-5 ;

[0053] x is the fire value of the microwave oven corresponding to the heating power of the microwave oven, which can be simply taken as 30, 40, 50, 60, 70.

[0054] The quadratic fitting results are shown in Table 2.

[0055] Table 2 Quadratic fitting parameters of hardness change of lotus root slices under different microwave powers

[0056] variety <![CDATA[k2]]> <![CDATA[R2 2 ]]> Elian No.5 0.019 0.88 Elian No.6 0.018 0.94 Wuzhi No.2 0.024 0.97 New Three Five 0.023 0.99 Ceteardia 0.029 0.93 Miancheng Lotus Root 0.030 0.95

[0057] As shown in Table 2, the quadratic fitting parameters k2, R2 and 2 All of them are greater than 0.88, indicating that the quadratic fitting effect is good. Among them, the k2 values ​​of Elian No. 5 and Elian No. 6 are close, about 0.020, the k2 values ​​of Wuzhi No. 2 and Xinsanwu are close, about 0.025, and the k2 values ​​of Huaqilian and Miancheng Lotus are close, about 0.030. Therefore,

[0058] The quadratic fitting parameter k2 of hardness is less than 0.020, which is defined as brittle lotus root;

[0059] The quadratic fitting parameter k2 of hardness is greater than 0.020 and less than 0.025, which is defined as both powdery and brittle;

[0060] The quadratic fitting parameter k2 of hardness is greater than 0.025, which is defined as pink lotus root.

[0061] The embodiments of the present invention have been described above, and the above description is exemplary, not exhaustive, and is not limited to the disclosed embodiments. Many modifications and changes will be apparent to those skilled in the art without departing from the scope and spirit of the described embodiments.

Claims

1. A method for analyzing and evaluating lotus root texture, characterized in that: The method comprises the following steps: S1: Collect lotus root samples of different varieties; S2: washing the sample of step S1, removing the lotus root skin and nodes, and slicing to obtain thin slices; S3: Place a weighing paper under the sheet and heat it in a microwave oven; S4: after the slice is heated, take it out, cool it to room temperature, and cut it into blocks; S5: measuring the block using a texture analyzer TPA mode to obtain texture data of the block; S6: sorting and standardizing the texture data of the block, and fitting it using a first-order kinetic model to obtain first-order kinetic fitting parameter data; S7: performing a second-order fitting on the first-order kinetic fitting parameter data by formula (1) to obtain second-order fitting parameter data; and determining the texture of the lotus root according to the second-order fitting parameter data; The formula (1) is ln(-k1)=ax+b, where: k1 is the first-order kinetic fitting parameter data; x is the firepower value of the microwave oven corresponding to the heating power of the microwave oven.

2. The lotus root texture analysis and evaluation method according to claim 1, wherein: In step S2, the middle section of the lotus root 1.5-2.5 cm away from the lotus root node is selected for slicing.

3. The method for analyzing and evaluating lotus root texture according to claim 1 or 2, wherein: The thickness of the sheet is 4.5-5.5 mm.

4. The method for analyzing and evaluating the texture of lotus root according to claim 1, wherein: In step S3, the heating power of the microwave oven is 200-600w, and the heating time is 0-85s.

5. The lotus root texture analysis and evaluation method according to claim 1 or 4, wherein: In step S3, the slices are placed in a microwave oven one at a time for heating.

6. The method for analyzing and evaluating the texture of lotus root according to claim 1, wherein: In the step S4, the lotus root flesh with holes on the edge of the lotus root is taken and cut into the blocks.

7. The lotus root texture analysis and evaluation method according to claim 1 or 6, wherein: The size of the block is (0.8-1.2) cm×(0.8-1.2) cm×(0.45-0.55) cm.

8. The method for analyzing and evaluating the texture of lotus root according to claim 1, wherein: In step S5, the operating parameters of the texture analyzer include: 900-1000N sensing element, P36R probe, test speed 55-65mm / min, test distance 0.8-1.2cm, trigger force 0.4-0.6N, and deformation amount 30-40%.

9. The method for analyzing and evaluating the texture of lotus root according to claim 1 or 8, wherein: The texture data of the block include: measurement time and hardness of the block.

10. The lotus root texture analysis and evaluation method according to claim 1, wherein: The quadratic fitting parameter data is k2; When k2<0.020, the lotus root is defined as a brittle lotus root; When 0.020<k2<0.025, the lotus root is defined as both soft and crispy; When k2>0.025, the lotus root is defined as pink lotus root.

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