Preparation method of cooked peeled and denucleated jujubes

Abstract

The preparation method comprises the following steps: (1) peeling and denucleating red dates, (2) putting the peeled and denucleated red dates into a constant temperature and humidity chamber, setting the temperature to be 65-85 DEG C and the humidity to be 65-85%, and controlling the cooking time to be 60-75 hours; and (3) putting the cooked red dates into a kang room, controlling the temperature at 60-65 DEG C, and drying for 12-18 hours. The product is low in fat, rich in dietary fiber, extremely low in sodium and low in GI. The sucrose content of the cooked peeled and pitted jujubes is 4.5 g / 100g, and is reduced by 80% or above compared with that of uncooked jujubes.

Description

Technical Field

[0001] The invention relates to the technical field of food processing, in particular to a method for preparing cooked peeled and pitted dates. Background Art

[0002] As a food with extremely high nutritional value, red dates are rich in protein, sugar, organic acid, vitamin A, vitamin C, and a variety of trace elements and amino acids. However, the traditional preparation method of red dates has many problems, such as uneven color, poor taste, short shelf life, and easy loss of nutrients during processing.

[0003] At present, the processing technology of cooked jujube is mainly divided into traditional process and modern fermentation process. The traditional process usually includes steps such as washing, boiling jujube and smoking. Although the process is simple, it has defects such as unsatisfactory color and taste and short shelf life. Modern fermentation technology improves the color, taste and nutritional value of cooked peeled and pitted jujube through solid-state fermentation or solid-liquid step-by-step fermentation. For example, the solid-state micro-fermentation method significantly improves the fermentation rate and cooking efficiency of red dates through high temperature and high humidity environment and ultrasonic treatment. The cooked peeled and pitted jujube has better flavor and is rich in polyphenols, flavonoids and other bioactive substances.

[0004] In addition, some innovative technologies, such as the application of Maillard reaction treatment liquid, further improved the color and flavor of cooked peeled and pitted dates, while reducing the loss of amino acids. However, the existing technology still has some shortcomings, such as high requirements for fermentation equipment, complex processes, and high production costs. Summary of the invention

[0005] The invention aims to provide a method for preparing cooked peeled and pitted dates, which can produce cooked peeled and pitted dates products with uniform color, full taste and long shelf life, and has high production efficiency and quality stability.

[0006] The technical solution of the present invention is as follows: A method for preparing cooked peeled and pitted dates, comprising the following steps: (1) Peel and remove the core of the red dates. (2) Place the peeled and pitted red dates in a constant temperature and humidity chamber, set the temperature to 65-85°C, the humidity to 65-85%, and control the cooking time to 60-75 hours; (3) Place the cooked red dates in a heated room, control the temperature at 60-65°C, and dry for 12-18 hours.

[0007] In the step (1), the red dates are peeled in a peeling machine, with a peeling rate of ≥80%, and then the peeled red dates are poured into a pitting machine for pitting, with a pitting rate of ≥98%.

[0008] In step (2), the temperature is set at 70-80°C and the humidity is set at 70-80%.

[0009] In step (2), the temperature is set to 75°C and the humidity is set to 75%.

[0010] During the cooking process of step (2), the red dates are turned over every 4-6 hours, and the temperature and humidity are measured every 4-6 hours.

[0011] The moisture content of the cooked red dates after drying in step (3) is 10-14%.

[0012] Beneficial effects of the present invention: The present invention is a low-fat, dietary fiber-rich, extremely low-sodium, low-GI product. During the cooking process, sucrose in red dates is converted into glucose and fructose, and the total acid and dietary fiber content increases. Dietary fiber is a low-energy substance that helps maintain normal intestinal function; the reduction in sucrose content and the increase in total acid content promote the sweet and sour taste of cooked peeled and pitted dates. The sucrose content of cooked peeled and pitted dates is 4.5g / 100g, which is more than 80% lower than that of unripened red dates.

[0013] During the ripening process of red dates, the content of glucose and fructose changes, and the aroma components also change significantly, giving the ripe peeled and pitted dates a unique flavor. The ripening process of red dates involves the Maillard reaction, enzymatic browning, and the reaction of endogenous microorganisms. These processes work together to make the red dates darker and improve their antioxidant capacity and functionality. The antioxidant capacity of ripened red dates is significantly enhanced, reaching an increase of 30% to 50% or more due to the increase in the content of reducing sugars, organic acids, and polyphenols. DETAILED DESCRIPTION

[0014] Example 1 Raw material selection: 75 kg of special grade Ruoqiang grey dates, with thick flesh, the color of red dates, no peculiar smell, 25% moisture, 0.1% impurities, and 1% defective fruit. Record the batch number of the raw materials.

[0015] Pretreatment of red dates: Peel the red dates in a peeling machine, with a peeling rate of 80%; pour the peeled dates into a pitting machine to remove the pits, with a pitting rate of 98%. After peeling and pitting, each tray weighs 1.5 kg, each cart can hold 60 trays, and each cart can bear 90 kg when fully loaded.

[0016] Red date processing: Put the peeled and pitted red dates into a constant temperature and humidity chamber, set the temperature to 75℃, the humidity to 75%, and control the processing time to 72 hours. Shake the plate every 4 hours to ensure that the material is evenly colored; measure the temperature and humidity every 4 hours to ensure a stable processing environment.

[0017] Drying of cooked peeled and pitted dates: Put the cooked red dates into a kang room, control the temperature at 60℃, and dry for 12 hours. During this period, the moisture content of the material is tested every 6 hours to ensure that the moisture content of the cooked peeled and pitted dates is controlled at about 10%. The drying process must ensure that the moisture content of the cooked peeled and pitted dates meets the standard. The length and width of the cooked peeled and pitted dates are 3.5*2.5 cm.

[0018] Selection: After drying, the cooked peeled and pitted dates are selected, and those with soft and falling skin, incomplete fruit shape or unqualified moisture are discarded.

[0019] Sterilization: The selected cooked peeled and pitted dates are sterilized with ozone at an ozone concentration of 50 mg / cubic meter for 60 minutes.

[0020] The results of the test of Example 1 are as follows: 1. Analysis of the nutrient element test results is shown in Table 1. According to the "National Food Safety Standard General Rules for Nutrition Labeling of Prepackaged Foods" (GB 28050), the fat content is 1.0g / 100g≤3g / 100g, which is low in fat; dietary fiber helps maintain normal intestinal function, and the dietary fiber content is 9.13g / 100g≥6g / 100g. According to the GB 28050 example, the product is rich in dietary fiber; the sodium content is 26 mg / 100g≤40mg / 100g, which is very low in sodium.

[0021] Table 1 Detection data analysis Test items Test results result energy 1403 kJ / 100g — protein 3.84 g / 100g — Fat 1.0 g / 100g Low in fat carbohydrate 72.2 g / 100g — Dietary fiber 9.13 g / 100g Rich in dietary fiber Total Sugar 56.7 g / 100g — glucose 24.1 g / 100g — fructose 27.9 g / 100g — sucrose 4.5 g / 100g — lactose Not detected — maltose 0.16 g / 100g — sodium 26 mg / 100g Very Low Sodium According to the health industry standard WS / T652-2019 of the People's Republic of China "Method for Determination of Glycemic Index of Food", the changes in blood sugar of volunteers after consuming the test substances were studied and tested, and their GI values ​​were obtained.

[0022] A total of 13 volunteers, 7 males and 6 females, were included. The products of Example 1 were consumed respectively, and blood glucose was measured 3 times independently. The results are shown in Table 2. The results show that, with glucose as a reference (GI is 100), the GI value of the product of Example 1 is 41. According to the food GI grading standard, the cooked peeled and pitted jujube (cooked peeled and pitted jujube) has a GI <55, which is a low GI food.

[0023] Table 2 GI value test Serial number 1 2 3 4 5 6 7 8 9 10 11 12 13 average GI value 58.82 45.94 39.65 26.05 62.30 39.49 22.35 33.28 26.86 38.74 35.54 34.48 65.44 41 2. Analysis of nutritional differences between red dates and the product of Example 1 The comparison of various indicators of red dates and Example 1 products is shown in Table 3. After the red dates are cooked at high temperature and high humidity, the sucrose value decreases from 36.3g / 100g to 4.5g / 100g, the glucose value increases from 13.5g / 100g to 24.1g / 100g, and the fructose value increases from 11.8g / 100g to 27.9g / 100g. This may be that sucrose is converted into reducing sugars such as glucose and fructose during the cooking process. The dietary fiber content increases from 7.20g / 100g to 9.13g / 100g, indicating that carbohydrates are partially converted during the cooking process. The total acid value increases from 5.28g / kg to 11.96g / kg, which may be due to the fact that the product of the accompanying Maillard reaction can decompose to produce acid, resulting in an increase in the total acid content. The cooked peeled and pitted dates of Example 1 present a sweet and sour taste.

[0024] Table 3 Comparison of carbohydrates, dietary fiber and total acid data between Example 1 and red dates project red dates Example 1 Total Sugar 61.6g / 100g 56.7 sucrose 36.3g / 100g 4.5 glucose 13.5g / 100g 24.1 fructose 11.8g / 100g 27.9 Dietary fiber 7.20g / 100g 9.13 Total acid (calculated as malic acid) 5.28g / kg 11.96 Example 2 1. A method for preparing cooked peeled and pitted dates, comprising the following steps: (1) Peel the red dates in a peeling machine, with a peeling rate of ≥80%, and then pour the peeled red dates into a pitting machine to remove the pits, with a pitting rate of ≥98%; (2) Place the peeled and pitted red dates in a constant temperature and humidity chamber, set the temperature to 65°C, the humidity to 65%, and the cooking time to 60 hours. During the cooking process, turn the red dates over every 4 hours, and measure the temperature and humidity every 4 hours. (3) Place the cooked red dates in a kang room, control the temperature at 60°C, and dry them for 12 hours. The moisture content of the cooked red dates after drying is 10-14%.

[0025] Example 3 1. A method for preparing cooked peeled and pitted dates, comprising the following steps: (1) Peel the red dates in a peeling machine, with a peeling rate of ≥80%, and then pour the peeled red dates into a pitting machine to remove the pits, with a pitting rate of ≥98%; (2) Place the peeled and pitted red dates in a constant temperature and humidity chamber, set the temperature to 85°C, the humidity to 85%, and the cooking time to 75 hours. During the cooking process, turn the red dates over every 6 hours, and measure the temperature and humidity every 6 hours. (3) Place the cooked red dates in a kang room, control the temperature at 65°C, and dry them for 18 hours. The moisture content of the cooked red dates after drying is 14%.

[0026] Example 4 1. A method for preparing cooked peeled and pitted dates, comprising the following steps: (1) Peel the red dates in a peeling machine, with a peeling rate of ≥80%, and then pour the peeled red dates into a pitting machine to remove the pits, with a pitting rate of ≥98%; (2) Place the peeled and pitted red dates in a constant temperature and humidity chamber, set the temperature to 75°C, the humidity to 75%, and the cooking time to 75 hours. During the cooking process, turn the red dates over every 5 hours, and measure the temperature and humidity every 5 hours. (3) The cooked red dates are placed in a kang room, the temperature is controlled at 62°C, and dried for 15 hours. The moisture content of the cooked red dates after drying is 12%.

[0027] Example 5 1. A method for preparing cooked peeled and pitted dates, comprising the following steps: (1) Peel the red dates in a peeling machine, with a peeling rate of ≥80%, and then pour the peeled red dates into a pitting machine to remove the pits, with a pitting rate of ≥98%; (2) Place the peeled and pitted red dates in a constant temperature and humidity chamber, set the temperature to 65°C and the humidity to 85%, and control the cooking time to 72 hours. During the cooking process, turn the red dates every 6 hours, and measure the temperature and humidity every 4 hours. (3) Place the cooked red dates in a kang room, control the temperature at 65°C, and dry them for 12 hours. The moisture content of the cooked red dates after drying is 10-14%.

[0028] Example 6 1. A method for preparing cooked peeled and pitted dates, comprising the following steps: (1) Peel the red dates in a peeling machine, with a peeling rate of ≥80%, and then pour the peeled red dates into a pitting machine to remove the pits, with a pitting rate of ≥98%; (2) Place the peeled and pitted red dates in a constant temperature and humidity chamber, set the temperature to 80°C, the humidity to 80%, and the cooking time to 75 hours. During the cooking process, turn the red dates over every 4 hours, and measure the temperature and humidity every 4 hours. (3) Place the cooked red dates in a kang room, control the temperature at 60°C, and dry them for 18 hours. The moisture content of the cooked red dates after drying is 10-14%.

Claims

1. A method for preparing cooked peeled and pitted dates, characterized in that: Here are the steps: (1) Peel and remove the core of the red dates. (2) Place the peeled and pitted red dates in a constant temperature and humidity chamber, set the temperature to 65-85°C, the humidity to 65-85%, and control the cooking time to 60-75 hours; (3) Place the cooked red dates in a heated room, control the temperature at 60-65°C, and dry for 12-18 hours.

2. The method for preparing cooked peeled and pitted dates according to claim 1, characterized in that: In the step (1), the red dates are peeled in a peeling machine, with a peeling rate of ≥80%, and then the peeled red dates are poured into a pitting machine for pitting, with a pitting rate of ≥98%.

3. The method for preparing cooked peeled and pitted dates according to claim 1, characterized in that: In step (2), the temperature is set at 70-80°C and the humidity is set at 70-80%.

4. The method for preparing cooked peeled and pitted dates according to claim 1, characterized in that: In step (2), the temperature is set to 75°C and the humidity is set to 75%.

5. The method for preparing cooked peeled and pitted dates according to claim 1, characterized in that: During the cooking process of step (2), the red dates are turned over every 4-6 hours, and the temperature and humidity are measured every 4-6 hours.

6. The method for preparing cooked peeled and pitted dates according to claim 1, characterized in that: The moisture content of the cooked red dates after drying in step (3) is 10-14%.