Carrot puree processing method capable of increasing polyphenol content

Abstract

The invention discloses a carrot puree processing method capable of increasing polyphenol content, which comprises the following steps: step (1) selecting fresh carrots without plant diseases and insect pests and pesticide residues, washing, and drying in the shade; (2) putting the raw materials into a solid-state fermentation bin for closed variable-temperature solid fermentation; (3) grinding the carrots subjected to solid-state fermentation to obtain carrot homogenate; and (4) putting the carrot homogenate into a liquid state fermentation bin for closed variable-temperature liquid state fermentation. Different from a traditional fruit and vegetable puree making method, the carrot puree is prepared through the solid-liquid state combined variable-temperature fermentation technology for the first time, the polyphenol content and the antioxidant activity can be greatly improved, wide market prospects are achieved, a new thought is provided for deep processing of carrots, and the carrot puree is worthy of popularization and application. And beneficial reference is provided for potential application of the high-antioxidant mashed carrot as a relatively good antioxidant health-preserving product in the aspect of food, and certain guiding significance is provided for promoting the development of the carrot industry.

Description

Technical Field

[0001] The invention belongs to the field of food processing and relates to a carrot puree processing method, in particular to a carrot puree processing method for increasing the polyphenol content. Background Art

[0002] Elderly people generally have problems with chewing, gastrointestinal motility, digestion and absorption, and their abilities are weak. Therefore, there is a huge market prospect for developing a fruit puree product that is low in sugar and additives and suitable for the elderly, which can promote gastrointestinal motility, is easy to absorb, has strong antioxidant properties and can slow down aging.

[0003] Carrots (Daucus carota L.) are rich in nutrients and are widely grown around the world. They are one of the world's top ten vegetable crops. Fresh carrots have a high water content of about 86-92%, are easily spoiled, and have poor flavor. Deep processing of carrots can extend their shelf life and increase their added value. At present, the most common deep-processed carrot products that are more suitable for elderly people with weak chewing ability are carrot juice, carrot jam and carrot puree.

[0004] During the production process of carrot juice, a large amount of residue will be left, the main components of which are cellulose and some insoluble dietary fiber. Cellulose is a complex carbohydrate and one of the main components of plant cell walls. It promotes intestinal peristalsis and aids digestion. Insoluble dietary fiber is also important for maintaining intestinal health. It can absorb water and increase stool volume, thereby promoting defecation and avoiding constipation. However, the current methods of making jams and purees generally have the problem of high added sugar. Excessive sugar intake can easily cause a series of diseases, which does not conform to the "three reductions" principle of reducing oil, salt, and sugar intake advocated by the Healthy China Action. Moreover, high-sugar processing methods may cause the loss of nutrients, especially polyphenols.

[0005] Polyphenols are secondary metabolites of plants, which have antioxidant, anti-aging and gastrointestinal motility-promoting effects. They can provide hydrogen atoms or electrons to prevent or remove reactive oxygen and reactive nitrogen in cells. In addition, polyphenol compounds can also regulate various cell signaling pathways, thereby enhancing the content of endogenous antioxidant enzymes in the human body, such as superoxide dismutase (SOD), glutathione peroxidase (GPx) and catalase (CAT). Polyphenols can delay cell aging during replication and extend the cell life cycle, which is essential for maintaining tissue and organ function. Polyphenols reduce inflammatory responses by inhibiting the production of inflammatory factors such as tumor necrosis factor-α (TNF-α) and interleukin-6 (IL-6); and can induce cell autophagy, helping cells to remove abnormally folded proteins and dysfunctional mitochondria, thereby slowing down the aging process. Polyphenols improve the intestinal microenvironment by promoting the growth of beneficial bacteria and inhibiting the reproduction of harmful bacteria, thus helping to maintain intestinal health. For example, polyphenols can increase the number of bifidobacteria and lactic acid bacteria, which are very important for maintaining intestinal barrier integrity and promoting intestinal motility. Polyphenols can stimulate the secretion of gastrointestinal hormones such as motilin and glucagon-like peptide-1 (GLP-1), which can enhance intestinal motility and promote intestinal peristalsis. Summary of the invention

[0006] Based on the shortcomings of existing carrot products, the present invention provides a method for processing carrot puree with high polyphenol content and strong antioxidant properties. The method uses fresh carrots as raw materials, does not require any addition, and uses a variable temperature fermentation technology combining solid and liquid to prepare carrot puree, which is brown in color, delicate in taste, sweet and sour in taste, and has a floral and fruity aftertaste. In addition, during the high temperature and high humidity fermentation process, some phenolic compounds will be released from the complex esterification and glycosylation structure and exist in a free state, which is mainly manifested in a substantial increase in total phenol content and antioxidant activity. At the same time, in order to meet actual production needs, a solid-liquid combined variable temperature fermentation carrot puree processing equipment is designed, and its total phenol content and antioxidant activity are measured, laying a theoretical foundation for its market launch.

[0007] The objective of the present invention is achieved through the following technical solutions:

[0008] A method for processing carrot puree to increase polyphenol content comprises the following steps:

[0009] Step (1) Select fresh carrots that are free of pests and diseases and pesticide residues, wash them, and dry them in the shade;

[0010] Step (2) putting the raw materials into a solid fermentation chamber for closed variable temperature solid fermentation: from room temperature for 3 to 6 hours, the temperature is raised to 85 to 95° C., and the humidity is raised to 100% RH; 85 to 95° C. is maintained for 2 to 5 hours; the temperature is lowered to 75 to 85° C. after 0.5 to 2 hours, and maintained for 8 to 18 hours; the temperature is lowered to 65 to 78° C. after 0.5 to 2 hours, and maintained for 18 to 36 hours; the humidity is maintained at 100% RH throughout the process;

[0011] Step (3) grinding the carrots after solid-state fermentation to obtain carrot homogenate;

[0012] Step (4) putting the carrot homogenate into a liquid fermentation bin for closed variable temperature liquid fermentation: the temperature and humidity are respectively raised to 65-75° C. and 100% RH, and maintained for 18-36 hours; after 0.5-2 hours, the temperature is reduced to 55-68° C. and the humidity is 70%-100% RH; the temperature is maintained at 55-68° C., and the humidity is reduced and maintained at 40%-90% RH for 18-36 hours.

[0013] A solid-liquid combined temperature-variable fermentation carrot puree processing device for realizing the above method comprises a solid fermentation chamber, a grinder, a liquid fermentation chamber, a fan, a heating chamber, an annular air duct, a homogenizing blade, a homogenizing motor, and a finished product pipeline, wherein:

[0014] The discharge port of the solid-state fermentation bin is connected to the feed port of the grinder;

[0015] The discharge port of the grinder is connected to the feed port of the liquid fermentation bin;

[0016] The discharge port of the liquid fermentation bin is connected to the finished product pipeline;

[0017] The liquid fermentation tank is provided with a homogenizing blade inside, and the homogenizing blade is provided with kinetic energy by a homogenizing motor;

[0018] The solid fermentation tank and the liquid fermentation tank are provided with an annular air duct outside;

[0019] The heating chamber is connected to the annular air duct, and the fan blows out the heat in the heating chamber and circulates the heat in the annular air duct to control the temperature of the solid fermentation chamber and the liquid fermentation chamber.

[0020] Compared with the prior art, the present invention has the following advantages:

[0021] 1. Different from the traditional method for making fruit and vegetable puree, the present invention prepares carrot puree by solid-liquid state combined with variable temperature fermentation technology for the first time, which can greatly improve the polyphenol content and antioxidant activity, has broad market prospects, provides new ideas for the deep processing of carrots, and provides a useful reference for the potential application of high antioxidant carrot puree as a better antioxidant health product in food, which has certain guiding significance for promoting the development of the carrot industry.

[0022] 2. After fresh carrots were prepared into carrot puree by solid-liquid state combined with temperature-variable fermentation technology, the total phenol content increased by about 721.1%; for DPPH, ABTS· + , PTIO, and ·OH radical scavenging abilities were increased by approximately 6.6, 2, 4.6, and 2.2 times, respectively.

[0023] 3. The special equipment designed by the present invention and matched with the process is simpler to operate, ensures the stability of fermentation, and improves production efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 It is a structural schematic diagram of a solid-liquid combined temperature-variable fermentation carrot puree processing device;

[0025] Figure 2 It is a top view of a solid-liquid combined temperature-variable fermentation carrot puree processing device;

[0026] In the figure, 1-solid fermentation chamber, 2-grinder, 3-liquid fermentation chamber, 4-fan, 5-heating chamber, 6-annular air duct, 7-homogenization motor (bevel gear + motor), 8-support frame, 9-grinder wiring box, 10-spoiler, 11-finished product pipeline. DETAILED DESCRIPTION

[0027] The technical solution of the present invention is further described below in conjunction with the accompanying drawings, but is not limited thereto. Any modification or equivalent replacement of the technical solution of the present invention without departing from the spirit and scope of the technical solution of the present invention should be included in the protection scope of the present invention.

[0028] The test materials used in the examples of the present invention are all conventional test materials in the art and can be purchased through commercial channels.

[0029] In the following implementation case, a VFD-6000 series vacuum freeze dryer produced by Beijing Boyikang Laboratory Instrument Co., Ltd. was used for freeze drying. After drying, the product was ground into powder for use in polyphenol extraction and antioxidant testing.

[0030] Polyphenol content detection: GB / T 8313-2018 method is used for determination.

[0031] Antioxidant activity assay:

[0032] DPPH free radical scavenging rate determination: Prepare 0.1mmol / L DPPH solution with anhydrous ethanol. Add 100μL of sample (according to the concentration gradient of 4, 6, 10, 15, 20, 40, 60mg / mL), then add 100μL of DPPH solution, shake well, react in the dark for 30min, and measure the absorbance at a wavelength of 517nm as A. Add 100μL sample and 100μL anhydrous ethanol in sequence, and measure the absorbance at a wavelength of 517nm as A. 对照 100 μL of 70% ethanol solution was taken and added to 100 μL of DPPH solution. The absorbance at a wavelength of 517 nm was measured as A0. The DPPH free radical scavenging rate was calculated according to formula (1).

[0033]

[0034] ABTS + Clearance determination: ABTS solution (7 mmol / L) and potassium persulfate solution (2.45 mmol / L) were mixed in equal proportions and placed in the dark at room temperature overnight. The next day, the mixed solution was diluted with anhydrous ethanol until the absorbance at 734 nm was 0.7 ± 0.02 to obtain ABTS· + Working solution. Add 200 μL of sample (according to the concentration gradient of 4, 6, 10, 15, 20, 40, 60 mg / mL), then add 4 mL of working solution, shake well, react at 30°C in the dark for 20 minutes, and measure the absorbance at a wavelength of 734 nm as A. Replace the working solution with anhydrous ethanol and measure the absorbance at a wavelength of 734 nm as A. 对照 . Replace the sample with 70% ethanol solution and measure the absorbance value A0 at a wavelength of 734nm. + The clearance rate was calculated according to formula (1).

[0035] PTIO free radical scavenging rate determination: accurately weigh 75 mg of PTIO powder into a conical flask, add 500 mL of deionized water, and dissolve by ultrasonic for 5 minutes to obtain a PTIO solution. Add 1 mL of sample (according to the concentration gradient of 4, 6, 10, 15, 20, 40, 60 mg / mL), then add 2 mL of PTIO solution, shake well, and place in a light-proof water bath at 37°C for 3 hours. The absorbance value at a wavelength of 557 nm is A. Replace the PTIO solution with deionized water, and the absorbance value at a wavelength of 557 nm is A. 对照 , the sample solution was replaced by 70% ethanol solution, and the absorbance value was measured at a wavelength of 557nm as A0. The PTIO free radical scavenging rate was calculated according to formula (1).

[0036] Determination of hydroxyl radical (·OH) scavenging rate: add 1 mL of sample (according to the concentration gradient of 4, 6, 10, 15, 20, 40, 60 mg / mL), then add 1 mL of ferrous sulfate solution (10 mmol / L), 1 mL of salicylic acid solution (10 mmol / L), and finally add 1 mL of hydrogen peroxide solution (8.8 mmol / L). Incubate in a 37°C water bath for 30 min. The absorbance at a wavelength of 510 nm is A. Replace H2O2 solution with deionized water. The absorbance at a wavelength of 510 nm is A. 对照 , the sample solution was replaced by 70% ethanol solution, and the absorbance at a wavelength of 510 nm was measured as A0. ·OH removal rate was calculated according to formula (1).

[0037] Embodiment 1:

[0038] (1) Raw material processing: Select fresh carrots without pests and diseases and pesticide residues, wash them, dry them in the shade, and put them into Figure 1 The solid-state fermentation chamber shown in the figure performs closed variable temperature solid fermentation, and its temperature control is provided by the heating chamber (heated by electric heating rods inside), and the heat is blown out by the fan and circulated in the annular air duct for heating.

[0039] (2) Solid-state fermentation: from room temperature, the temperature was raised to 90°C after 5 h, and the humidity was raised to 100% RH; 90°C was maintained for 5 h; the temperature was lowered to 80°C after 1 h and maintained for 12 h; the temperature was lowered to 72°C after 1 h and maintained for 24 h; the humidity was maintained at 100% RH throughout the process.

[0040] (3) After the solid-state fermentation is completed, the feed port of the grinder is opened and the carrots after the solid-state fermentation are ground to obtain carrot slurry, which is then discharged into a liquid fermentation bin for liquid variable temperature fermentation. A homogenizing blade is arranged in the liquid fermentation bin, and kinetic energy is provided by a homogenizing motor. The temperature is controlled by a heating bin (which is heated by an electric heating rod) providing heat, and the heat is blown out by a fan, and circulated and heated in an annular air duct.

[0041] (4) Liquid fermentation: Keep the temperature at 72°C and humidity at 100%RH for 24 hours; lower the temperature to 65°C and humidity to 90%RH for 1 hour; keep 65°C, lower the humidity and keep 70%RH for 23 hours. After fermentation is completed, pump it out through the finished product pipeline.

[0042] (5) Detection method: After processing, the puree was freeze-dried and the total phenol content and antioxidant activity were detected. The results are shown in Table 1.

[0043] Comparative Example 1:

[0044] (1) Raw material processing: fresh carrots without pests and diseases and pesticide residues were selected, washed, dried in the shade, cut into 2.5 cm segments, put into sealed plastic bags, sealed the bags tightly, and sent to a programmable constant temperature test box (BOS-150L, ​​Xiamen Boshi Testing Equipment Co., Ltd.) for variable temperature solid-state fermentation.

[0045] (2) Solid-state fermentation: From room temperature, the temperature was raised to 93°C over 5 hours. The temperature was maintained at 93°C for 3 hours. The temperature was lowered to 85°C over 1 hour and maintained for 12 hours. The temperature was lowered to 75°C over 1 hour and maintained for 24 hours.

[0046] (3) Puree homogenization: Under sterile conditions, the solid-state fermented carrots and their drain are homogenized using a colloid mill, and then put into a sealed bag again. The bag is sealed tightly and then sent to a programmable constant temperature test chamber for liquid fermentation.

[0047] (4) Liquid fermentation: Continue to maintain 72°C for 24 hours; after 1 hour, reduce the temperature to 65°C and maintain for 23 hours.

[0048] (5) Detection method: After processing, the puree was freeze-dried and the total phenol content and antioxidant activity were detected. The results are shown in Table 1.

[0049] Comparative Example 2: (Constant Temperature Solid State)

[0050] (1) Raw material processing: fresh carrots without pests and diseases and pesticide residues were selected, washed, dried in the shade, cut into 2.5 cm segments, put into sealed plastic bags, sealed the bags tightly, and sent to a programmable constant temperature test box (BOS-150L, ​​Xiamen Boshi Testing Equipment Co., Ltd.) for constant temperature solid-state fermentation.

[0051] (2) Solid-state fermentation: Solid-state fermentation was carried out at a constant temperature of 75°C for 5 days.

[0052] (3) Puree homogenization: Under sterile conditions, solid-state fermented carrots and their drain are homogenized using a colloid mill.

[0053] (4) Detection method: After processing, the puree was freeze-dried and the total phenolic content and antioxidant activity were detected. The results are shown in Table 1.

[0054] Comparative Example 3: (Constant Temperature Solid-Liquid)

[0055] (1) Raw material processing: fresh carrots without pests and diseases and pesticide residues were selected, washed, dried in the shade, cut into 2.5 cm segments, put into sealed plastic bags, sealed the bags tightly, and sent to a programmable constant temperature test box (BOS-150L, ​​Xiamen Boshi Testing Equipment Co., Ltd.) for constant temperature solid-state fermentation.

[0056] (2) Solid-state fermentation: Solid-state fermentation was carried out at a constant temperature of 75°C for 2 days.

[0057] (3) Puree homogenization: Under sterile conditions, the solid-state fermented carrots and their drain are homogenized using a colloid mill, and then put into a sealed bag again. The bag is sealed tightly and then sent to a programmable constant temperature test chamber for liquid fermentation.

[0058] (4) Liquid fermentation: Continue to maintain 75°C for 2 days.

[0059] (5) Detection method: After processing, the puree was freeze-dried and the total phenol content and antioxidant activity were detected. The results are shown in Table 1.

[0060] Comparative Example 4: (Variable Temperature Solidification)

[0061] (1) Raw material processing: Select fresh carrots that are free of pests and diseases and pesticide residues, wash them, dry them in the shade, and put them into special fermentation equipment for closed temperature-variable fermentation.

[0062] (2) Solid-state fermentation: from room temperature, the temperature was raised to 90°C after 5 hours, and the humidity was 100% RH; 90°C was maintained for 5 hours; the temperature was lowered to 80°C after 1 hour and maintained for 12 hours; the temperature was lowered to 72°C after 1 hour and maintained for 48 hours; the temperature was further maintained at 72°C; the temperature was lowered to 65°C after 1 hour and maintained for 23 hours. The humidity was maintained at 100% RH throughout the process.

[0063] (3) Fruit puree homogenization: Start the internal homogenization mechanism of the fermentation equipment.

[0064] (4) Detection method: After processing, the puree was freeze-dried and the total phenolic content and antioxidant activity were detected. The results are shown in Table 1.

[0065] Comparative Example 5: (Constant Temperature Liquid)

[0066] (1) Raw material processing: fresh carrots without pests and diseases and pesticide residues were selected, washed, dried in the shade, homogenized, put into sealed plastic bags, sealed the bags tightly, and sent to a programmable constant temperature test box (BOS-150L, ​​Xiamen Boshi Testing Equipment Co., Ltd.) for constant temperature liquid fermentation.

[0067] (2) Liquid fermentation: Solid-state fermentation was carried out at a constant temperature of 75°C for 5 days.

[0068] (3) Detection method: After processing, the puree was freeze-dried and the total phenolic content and antioxidant activity were detected. The results are shown in Table 1.

[0069] Table 1 Physical and chemical properties and taste changes of carrot puree in six processing methods

[0070]

Claims

1. A method for processing carrot puree to increase polyphenol content, characterized in that The method comprises the following steps: Step (1) Select fresh carrots that are free of pests and diseases and pesticide residues, wash them, and dry them in the shade; Step (2) putting the raw materials into a solid fermentation chamber for closed variable temperature solid fermentation: from room temperature for 3 to 6 hours, the temperature is raised to 85 to 95° C., and the humidity is raised to 100% RH; 85 to 95° C. is maintained for 2 to 5 hours; the temperature is lowered to 75 to 85° C. after 0.5 to 2 hours, and maintained for 8 to 18 hours; the temperature is lowered to 65 to 78° C. after 0.5 to 2 hours, and maintained for 18 to 36 hours; the humidity is maintained at 100% RH throughout the process; Step (3) grinding the carrots after solid-state fermentation to obtain carrot homogenate; Step (4) putting the carrot homogenate into a liquid fermentation bin for closed variable temperature liquid fermentation: the temperature and humidity are respectively raised to 65-75° C. and 100% RH, and maintained for 18-36 hours; after 0.5-2 hours, the temperature is reduced to 55-68° C. and the humidity is 70%-100% RH; the temperature is maintained at 55-68° C., and the humidity is reduced and maintained at 40%-90% RH for 18-36 hours.

2. The method for processing carrot puree to increase polyphenol content according to claim 1, characterized in that In the step (2), the variable temperature solid fermentation conditions are preferably: from room temperature to 90°C after 5 hours, the humidity is increased to 100% RH; 90°C is maintained for 5 hours; the temperature is lowered to 80°C after 1 hour and maintained for 12 hours; the temperature is lowered to 72°C after 1 hour and maintained for 24 hours; the humidity is maintained at 100% RH throughout the process.

3. The method for processing carrot puree with increased polyphenol content according to claim 1, characterized in that In the step (3), the variable temperature liquid fermentation conditions are preferably: the temperature and humidity are raised to 72°C and 100% RH respectively, and maintained for 24 hours; the temperature is reduced to 65°C and the humidity is 90% RH for 1 hour; the temperature is maintained at 65°C, the humidity is reduced and maintained at 70% RH for 23 hours.

4. A solid-liquid combined temperature-variable fermentation carrot puree processing device for implementing the method described in any one of claims 1 to 3, characterized in that The device comprises a solid fermentation chamber, a grinder, a liquid fermentation chamber, a fan, a heating chamber, an annular air duct, homogenizing blades, a homogenizing motor, and a finished product pipeline, wherein: The discharge port of the solid-state fermentation bin is connected to the feed port of the grinder; The discharge port of the grinder is connected to the feed port of the liquid fermentation bin; The discharge port of the liquid fermentation bin is connected to the finished product pipeline; The liquid fermentation tank is provided with a homogenizing blade inside, and the homogenizing blade is provided with kinetic energy by a homogenizing motor; The solid fermentation tank and the liquid fermentation tank are provided with an annular air duct outside; The heating chamber is connected to the annular air duct, and the fan blows out the heat in the heating chamber and circulates the heat in the annular air duct to control the temperature of the solid fermentation chamber and the liquid fermentation chamber.

5. The solid-liquid combined temperature-variable fermentation carrot puree processing device according to claim 4, characterized in that The heating chamber is provided with an electric heating rod for heating.

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