Processing method of longan fruit powder
By adding maltodextrin, β-cyclodextrin, and soy protein to longan fruit powder and combining it with an appropriate drying time, the problem of longan fruit powder easily clumping was solved, and its solubility and taste were improved.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- GUANGDONG UNIV OF PETROCHEMICAL TECH
- Filing Date
- 2026-03-19
- Publication Date
- 2026-06-05
AI Technical Summary
Traditional longan fruit powder tends to clump and has poor solubility and taste.
Maltodextrin, β-cyclodextrin, and soy protein are added during the production of longan fruit powder, and the process parameters, such as drying time, are optimized through vacuum freeze-drying.
It effectively prevents longan fruit powder from clumping, improves solubility and fluidity, and maintains the original aroma and taste.
Smart Images
Figure CN122139907A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of food processing technology, and in particular to a method for processing longan fruit powder. Background Technology
[0002] Longan fruit powder is a food ingredient made primarily from longan (also known as dried longan fruit pulp) through a special processing technique. It appears as a brownish-yellow powder, is water-soluble, and is commonly used in beverage preparation and food processing. The main ingredient is fresh longan, which is dried using hot air drying technology to remove moisture, followed by ultra-fine grinding to a fine powder state. Hot air drying uses circulating hot air to evenly heat the raw material, preserving the polysaccharides, vitamins, and other active ingredients in the longan while preventing nutrient loss due to high temperatures. Ultra-fine grinding uses high-speed mechanical grinding to achieve a powder particle size of micrometers, improving solubility and a smooth texture. The entire process does not add pigments or preservatives, meeting the purity requirements for food ingredients.
[0003] However, it's easy to understand that traditional longan fruit powder has a high viscosity, making it prone to clumping. Summary of the Invention
[0004] In view of the shortcomings of the prior art, one of the objectives of the present invention is to provide a method for processing longan fruit powder, and another objective of the present invention is to provide longan fruit powder obtained by the method for processing longan fruit powder.
[0005] One of the objectives of this invention is achieved through the following technical solution: A method for processing longan fruit powder includes the following steps: Maltodextrin was added to the raw material of longan fruit powder to obtain the finished longan fruit powder product.
[0006] Preferably, the amount of maltodextrin added is 20%-30% of the total mass of the longan fruit powder finished product.
[0007] Furthermore, it also includes the following steps: The longan fruit powder is dried to obtain the finished longan fruit powder product.
[0008] Preferably, the drying time is 60-80 hours.
[0009] Furthermore, it also includes the following steps: Soy protein was added to the raw material of longan fruit powder to obtain the finished longan fruit powder product.
[0010] Preferably, the amount of soybean protein added is 3%-5% of the total mass of the longan fruit powder product.
[0011] Furthermore, it also includes the following steps: β-cyclodextrin was added to longan fruit powder raw material to obtain longan fruit powder finished product.
[0012] Preferably, the amount of β-cyclodextrin added is 4%-8% of the total mass of the longan fruit powder product.
[0013] The second objective of this invention is achieved through the following technical solution: A finished product of longan fruit powder obtained by the above processing method.
[0014] Preferably, the amount of maltodextrin added is 25% of the total mass of the longan fruit powder finished product, the drying time is 70 hours, the amount of soybean protein added is 3% of the total mass of the longan fruit powder finished product, and the amount of β-cyclodextrin added is 8% of the total mass of the longan fruit powder finished product.
[0015] The beneficial effects of this invention are as follows: Maltodextrin, as an anti-caking agent, can not only prevent clumping when added to longan fruit powder, but also increase its solubility. However, if the proportion of maltodextrin added during the production of longan fruit powder is too high, it will mask the original aroma of longan. β-Cyclodextrin can play a certain stabilizing role for volatile substances and heat- and light-sensitive substances. At the same time, β-Cyclodextrin can also improve the solubility and flowability of longan fruit powder. Soy protein has good flowability and a high glass transition temperature. When added to longan fruit powder, it can play an anti-caking role. Drying reduces the moisture in longan fruit powder, thereby improving its flowability and solubility. Attached Figure Description
[0016] Figure 1 The effect of maltodextrin addition on the quality of longan fruit powder.
[0017] Figure 2 The effect of β-cyclodextrin addition on the quality of longan fruit powder.
[0018] Figure 3 The effect of soybean protein addition on the quality of longan fruit powder.
[0019] Figure 4 The effect of drying time on the quality of longan fruit powder. Detailed Implementation
[0020] The following is a further explanation with reference to specific implementation methods: Experimental materials description: The raw material of longan fruit powder is the original pulp of fresh longan after being frozen and pulverized with liquid nitrogen, which is in block and granular form; maltodextrin (food grade), soy protein (food grade), β-cyclodextrin (food grade), citric acid (food grade) and sucrose were all purchased from the market.
[0021] The experimental equipment includes: an induction cooker, a deionized pure water system, an electronic analytical balance, a viscometer, a Fevik vacuum freeze dryer, a universal electric furnace, a pulverizer, a high-speed blender, and an ultra-low temperature freezer.
[0022] Single-factor experiment The effect of maltodextrin addition on the quality of longan fruit powder The percentage of β-cyclodextrin added (i.e., the percentage of added amount to the total mass of the longan fruit powder product, the same below) was set at 6%, and the percentage of added soy protein was set at 5%. The effect of the percentage of added maltodextrin on the quality of longan fruit powder was discussed. Maltodextrin was mixed evenly at addition amounts of 15%, 20%, 25%, 30%, and 35%, with a total sample size of 50g. The drying time was set to 70h, and the samples were labeled 1, 2, 3, 4, and 5, respectively, and then subjected to vacuum freeze-drying. After drying, the products were subjected to sensory evaluation and graphs were plotted to determine the appropriate amount of maltodextrin added for making longan fruit powder.
[0023] Effect of β-cyclodextrin addition on the quality of longan fruit powder The effects of β-cyclodextrin addition percentage on the quality of longan fruit powder were investigated, with maltodextrin at 30% and soy protein at 5%. β-cyclodextrin was added at concentrations of 2%, 4%, 6%, 8%, and 10%, mixed thoroughly, and dried for 70 hours. The mixtures were labeled 1, 2, 3, 4, and 5, respectively, and then freeze-dried under vacuum. Sensory evaluation of the dried products was performed, and charts were generated to determine the optimal β-cyclodextrin addition amount for producing longan fruit powder.
[0024] The effect of soybean protein addition on the quality of longan fruit powder The effects of soy protein addition percentages on the quality of longan fruit powder were investigated, with maltodextrin added at 30% and β-cyclodextrin at 6%. Soy protein was added at concentrations of 2%, 3%, 4%, 5%, and 6% respectively, mixed thoroughly, and dried for 70 hours. The mixtures were labeled 1, 2, 3, 4, and 5, and then subjected to vacuum freeze-drying. Sensory evaluation of the products was performed after drying, and charts were generated to determine the optimal soy protein addition amount for producing longan fruit powder.
[0025] The effect of drying time on the quality of longan fruit powder The percentages of maltodextrin, β-cyclodextrin, and soy protein added were set at 30%, 6%, and 5%, respectively. The effect of drying time on the quality of longan fruit powder was discussed. 50g of each of the above ingredients and longan were mixed and placed in a container, and vacuum freeze-drying was initiated. Drying times were set at 40h, 50h, 60h, 70h, and 80h. After drying, sensory evaluation of the products was conducted, and charts were generated to determine the optimal drying time for producing longan fruit powder.
[0026] Food sensory evaluation The longan fruit powder was evaluated using a comprehensive sensory assessment, considering five aspects: aroma, taste, color, texture, and solubility (20 points each, total 100 points). Eight students with prior experience in food sensory evaluation were invited to serve as assessors and conduct the sensory evaluation of the prepared longan fruit powder. Students scored the aroma, taste, color, texture, and solubility of the longan fruit powder according to their personal preferences and taste preferences, with two students forming a group. Specific criteria for the product sensory evaluation are shown in Table 1.
[0027] Before conducting sensory evaluations of food, evaluators should avoid being excessively hungry or full, and should also avoid eating strongly flavored foods, as these could affect the food evaluation scores and lead to significant deviations in the results. In addition, mouthwash can be provided to evaluators to rinse their mouths before each tasting. This is to reduce the influence of taste residue from the previous tasting on the current result, thus making the evaluation more accurate and reliable. The sensory evaluation of longan fruit powder is shown in Table 1.
[0028] Table 1 Sensory Evaluation Table for Longan Fruit Powder Food
[0029] Orthogonal experimental design for longan fruit powder After completing the single-factor level experiments, maltodextrin addition (A), β-cyclodextrin addition (B), soybean protein addition (C), and drying time (D) were selected as factors for the orthogonal experiment, and a four-factor, three-level orthogonal experiment was designed. The orthogonal experiment factor levels are shown in Table 2.
[0030] Table 2. Factor Level Table for Orthogonal Experiment
[0031] Viscosity testing Take 50g each of longan fruit powder (without maltodextrin, β-cyclodextrin, and soy protein) and longan fruit powder (with 20% maltodextrin, 8% β-cyclodextrin, and 3% soy protein added) after vacuum freeze-drying. Add 500g of purified water to each beaker and stir well. Use a viscometer with rotor #1 set to 12 rpm to measure the viscosity of both fruit powders dissolved in water. Perform three parallel tests and take the average value. Investigate the effects of maltodextrin, β-cyclodextrin, and soy protein on reducing the viscosity of fruit powders.
[0032] Results of the effect of maltodextrin addition on the quality of longan fruit powder The results of single-factor experiments show that maltodextrin, as an anti-caking agent, not only prevents clumping in the production of longan fruit powder but also increases its solubility. However, when the proportion of maltodextrin added during the production of longan fruit powder is too high, it can mask the original aroma of longan and make the flavor too sweet. Furthermore, it may reduce the yield of longan fruit powder. Analysis of Table 3 shows that when the maltodextrin addition amount is 25%, the longan fruit powder achieves the highest sensory score, exhibiting not only good solubility but also preserving the original flavor of longan. Therefore, orthogonal experiments were conducted with maltodextrin addition percentages of 20%, 25%, and 30%. The effect of maltodextrin addition amount on the quality of longan fruit powder is shown in Table 3 and [Table data missing]. Figure 1 .
[0033] Table 3. Effect of maltodextrin addition on the quality of longan fruit powder
[0034] Results of the effect of β-cyclodextrin on the quality of longan fruit powder β-Cyclodextrin can play a certain stabilizing role for volatile substances and substances sensitive to heat and light. Meanwhile, β-Cyclodextrin... It can also improve the solubility and flowability of longan fruit powder. Therefore, adding β-cyclodextrin as an auxiliary drying agent during the powdering process, combined with the effect of maltodextrin, can improve the solubility and flowability of longan fruit powder. Table 4 shows that when the maltodextrin addition is 30%, the soy protein addition is 5%, and the drying time is 70 hours, the sensory score of longan fruit powder initially increases with the increase of the percentage of β-cyclodextrin addition. When the percentage reaches 6%, the sensory score reaches its maximum. However, when the percentage of β-cyclodextrin addition continues to increase, the sensory score decreases. This is because the addition of β-cyclodextrin can increase the solubility and flowability of longan fruit powder. However, with increasing amounts, excessive β-cyclodextrin addition can weaken the longan aroma of the longan fruit powder itself, which will affect the quality of the fruit powder. Therefore, orthogonal experiments were conducted with β-cyclodextrin addition percentages of 4%, 6%, and 8% as three levels. The effect of β-cyclodextrin addition on the quality of longan fruit powder is shown in Table 4 and... Figure 2 .
[0035] Table 4. Effect of β-cyclodextrin addition on the quality of longan fruit powder
[0036] Results of the effect of soybean protein on the quality of longan fruit powder Soy protein has good flowability and a high glass transition temperature. Adding it to longan fruit powder production can prevent clumping and improve the flowability of the powder. Table 5 shows that with 30% maltodextrin, 6% β-cyclodextrin, and a drying time of 70 hours, the sensory score of the longan fruit powder initially increased with increasing soy protein content. The highest score of 91 points was reached when the soy protein content was 4%. However, the sensory score decreased as the soy protein content continued to increase. This is because a certain amount of soy protein can reduce the viscosity and improve the flowability of the powder. However, excessive soy protein can affect the original flavor of longan, giving the longan fruit powder a beany taste, which negatively impacts its flavor. Therefore, orthogonal experiments were conducted with soy protein content of 3%, 4%, and 5% as three levels. The effect of soy protein content on the quality of longan fruit powder is shown in Table 5. Figure 3 .
[0037] Table 5. Effects of soybean protein addition on the quality of longan fruit powder
[0038] Results of the effect of drying time on the quality of longan fruit powder The drying time also has a significant impact on longan fruit powder. If the drying time is insufficient, the longan fruit powder will not form a powder and will be too sticky. If the drying time is too long, it will not only affect the service life of the components of the vacuum freeze dryer, but also the moisture content of the fruit powder will be very low in the later stages of drying. Continuing to dry at this point will not only fail to improve the quality of the longan fruit powder, but may even reduce its quality. Table 6 shows that when the addition of maltodextrin is 30%, β-cyclodextrin is 6%, and soy protein is 5%, the sensory score of the product is very low when the drying time is less than 60 hours. This is because the moisture in the fruit powder product is not completely dried at this time. The longan fruit powder at this stage not only has high viscosity but also poor flowability and solubility. When the drying time reaches 60 hours, the sensory score slowly increases because most of the moisture in the sample has been dried, and the drying rate slows down. When the drying time reaches 70 hours, the sensory score reaches its highest point of 85 points. At this point, the longan fruit powder is completely dried, and the moisture content is very low. The flowability and solubility of the longan fruit powder are good. When the drying time continues to increase, the sensory scores become largely indistinguishable because drying is complete at this point. Continuing to dry will not improve the quality of the fruit powder; on the contrary, excessively long drying times will negatively impact its quality. Therefore, drying times of 60h, 70h, and 80h were selected as three levels for orthogonal experiments. The effect of drying time on the quality of longan fruit powder is shown in Table 6 and Figure 4 .
[0039] Table 6. Effects of drying time on the quality of longan fruit powder
[0040] Analysis of the results of the orthogonal experiment on longan fruit powder Analysis of Table 7 shows that, based on the magnitude of R, the order of importance of factors influencing the sensory evaluation of longan fruit powder is A > D > C > B. That is, maltodextrin addition > drying time > soy protein addition > β-cyclodextrin addition. Comparing the average values of the indicators with the relationships between each factor reveals that the optimal combination of processing conditions for producing longan fruit powder is A2B3C1D2. The results of the orthogonal experiment are shown in Table 7; the intersubjectivity effect test is shown in Table 8.
[0041] Table 7 Results of the orthogonal experiment
[0042] Table 8. Inter-subject effects test Dependent variable: sensory rating
[0043] Using the percentage of β-cyclodextrin as a blank group, the results of the above orthogonal experiment were analyzed using SPSS software. Table 8 shows the results. The corrected model's F=32.250, with a significance level of 0.001 < P < 0.05, indicating that the data is significant. This demonstrates that at least one factor has a significant impact on the sensory score. The table shows that the percentage of maltodextrin and drying time significantly affect the sensory score, while the percentage of soy protein has no significant effect. Through orthogonal experimental results and between-subjects effects testing, it can be concluded that under the conditions of this orthogonal experiment, the percentage of maltodextrin and drying time have an impact on the sensory score, while the percentage of soy protein has little effect.
[0044] Verification Experiment The optimal milling process obtained from the orthogonal experiment was repeated three times, and the average value was taken to verify whether this milling process combination was the optimal combination. The verification experimental results are shown in Table 9.
[0045] Table 9 Verification Experiment
[0046] The final experimental result was a sensory score of 90.67, which was higher than all combinations in the orthogonal experiment. Therefore, this experiment can confirm that the optimal conditions for longan flour production are 25% maltodextrin, 8% β-cyclodextrin, 3% soybean protein, and 70 hours of drying time.
[0047] Viscosity test results Longan fruit powder (finished product) with 25% maltodextrin, 8% β-cyclodextrin, and 3% soy protein added showed viscosities of 7.48 cp, 7.47 cp, and 7.49 cp in three parallel viscometer tests, with the average being 7.48 cp. Longan fruit powder (finished product) without these three added materials showed viscosities of 14.95 cp, 14.96 cp, and 14.94 cp in three viscometer tests, with the average being 14.95 cp (all drying times were 70 hours). Furthermore, during the dissolution step, it was observed that the longan fruit powder (finished product) without these three added materials not only dissolved very slowly, but also clumped upon entering the water, further slowing its dissolution. In contrast, the longan fruit powder (finished product) with added maltodextrin, β-cyclodextrin, and soy protein dissolved quickly and did not clump. Analysis shows that adding maltodextrin, β-cyclodextrin, and soy protein not only helps reduce the viscosity of longan fruit powder but also increases its dissolution rate.
[0048] The embodiments and descriptions above are merely illustrative of the principles and preferred embodiments of the present invention. Various changes and modifications may be made to the present invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the present invention as claimed.
Claims
1. A method for processing longan fruit powder, characterized in that, Includes the following steps: Maltodextrin was added to the raw material of longan fruit powder to obtain the finished longan fruit powder product.
2. The method for processing longan fruit powder according to claim 1, characterized in that: The amount of maltodextrin added is 20%-30% of the total mass of the longan fruit powder finished product.
3. The method for processing longan fruit powder according to claim 2, characterized in that: It also includes the following steps: The longan fruit powder is dried to obtain the finished longan fruit powder product.
4. The method for processing longan fruit powder according to claim 3, characterized in that: The drying time is 60-80 hours.
5. The method for processing longan fruit powder according to claim 4, characterized in that: It also includes the following steps: Soy protein was added to the raw material of longan fruit powder to obtain the finished longan fruit powder product.
6. The method for processing longan fruit powder according to claim 5, characterized in that: The amount of soybean protein added is 3%-5% of the total mass of the longan fruit powder finished product.
7. The method for processing longan fruit powder according to claim 6, characterized in that: It also includes the following steps: β-cyclodextrin was added to longan fruit powder raw material to obtain longan fruit powder finished product.
8. The method for processing longan fruit powder according to claim 7, characterized in that: The amount of β-cyclodextrin added is 4%-8% of the total mass of the longan fruit powder finished product.
9. A finished longan fruit powder product obtained by the longan fruit powder processing method described in claim 8.
10. The longan fruit powder product according to claim 9, characterized in that: The amount of maltodextrin added is 25% of the total mass of the longan fruit powder finished product, the drying time is 70 hours, the amount of soybean protein added is 3% of the total mass of the longan fruit powder finished product, and the amount of β-cyclodextrin added is 8% of the total mass of the longan fruit powder finished product.