Method for increasing content of synanthrin in jerusalem artichoke based on solid state fermentation technology

Abstract

The invention relates to a method for increasing the content of synanthrin in jerusalem artichoke based on a solid-state fermentation technology. The fermented jerusalem artichoke product is obtained through the steps of cleaning and slicing fresh jerusalem artichoke, air-drying, spraying wine, adding salt, uniformly stirring, filling into a pottery jar, compacting and sealing an opening of the jar, fermenting and the like. According to the technology for increasing the content of the synanthrin in the jerusalem artichoke based on the solid state fermentation, the production cost and the process complexity are remarkably reduced, and the yield of the synanthrin is increased. The method for increasing the synanthrin content is simple in used equipment, low in energy consumption, green and environment-friendly in the whole process and low in environmental load, the obtained product is flexible and controllable in form, and the industrial application scene of the jerusalem artichoke synanthrin can be greatly expanded.

Description

Technical Field

[0001] This invention relates to the field of fermentation technology, and in particular to a method for increasing the inulin content of Jerusalem artichoke based on solid-state fermentation technology. Background Technology

[0002] Jerusalem artichoke is a plant rich in inulin, an excellent natural prebiotic widely used in the food, health product, and pharmaceutical industries. Drying Jerusalem artichoke and then pulverizing it at low temperatures yields unpurified inulin, which can be used as a dietary supplement. However, this directly pulverized product is limited by the composition of the raw material itself. Not only is the inulin content insufficient to meet the purity requirements of industrial production, but its inherent bitter flavor also restricts its application in high-end foods and health products. To fully realize the prebiotic value of inulin and improve product quality and applicability, further extraction of inulin from Jerusalem artichoke is necessary. Currently, the main extraction methods for inulin include water extraction, acid-base extraction, and other methods. Hot water extraction involves immersing fresh or dried Jerusalem artichoke slices or pulp in hot water for extraction, followed by multiple processing steps to obtain inulin powder. This method is widely used, but high temperatures can easily cause inulin degradation, resulting in low extraction efficiency. Acid-base extraction / enzymatic methods utilize acids, alkalis, or inulin endopeptidase to break down the cell walls of the raw materials to increase the inulin dissolution rate, resulting in a higher extraction rate. However, these methods are costly and can easily introduce chemical or enzyme residues, making them unsuitable for "clean label" products.

[0003] Pickling is a common method for making kimchi, fermented ginger slices, and other foods. Pickling Jerusalem artichoke slices mainly involves two methods: one is to add salt, vinegar, chili powder, and other seasonings, marinate for a period of time, and eat immediately; the other involves washing, cutting, adding salt (sometimes sugar or spices), packing into containers, and sealing, relying on the natural microorganisms attached to the surface of the raw materials for room-temperature fermentation. The main purpose is to utilize lactic acid bacteria and other microorganisms to produce a sour taste, extend shelf life, and develop a unique flavor, rather than to efficiently produce or convert specific functional components (such as inulin). Traditional fermentation technology relies on the microbial community in the natural environment, which is complex. The unstable fermentation process leads to large quality differences between batches of products. Furthermore, it lacks scientific design and precise control over key process parameters such as initial moisture content, salinity, fermentation aids, temperature, and time, making it impossible to achieve high-yield inulin production. Summary of the Invention

[0004] To address the shortcomings of existing technologies, this invention proposes a Jerusalem artichoke solid-state fermentation technology.

[0005] This invention provides a solid-state fermentation technology for Jerusalem artichoke. Jerusalem artichoke slices are air-dried, then seasonings are sprayed on, mixed well, and sealed in a ceramic container. Fermentation is carried out at 10-25℃ for 30-45 days to obtain the fermented product. The container can also be any type of glass jar or food-grade stainless steel container. Selecting fresh, unrotten Jerusalem artichokes and slicing them increases the surface area, facilitating moisture evaporation and contact between microorganisms and the material during subsequent fermentation.

[0006] Fermentation temperature controlled between 10-25℃ is unfavorable for the rapid reproduction of spoilage bacteria at room temperature, but suitable for the slow growth of lactic acid bacteria and certain yeasts. The long fermentation time ensures that microorganisms have sufficient time to secrete pectinase, cellulase, etc., gradually breaking down the cell wall structure of Jerusalem artichoke, maximizing the dissolution of inulin within the cells. Simultaneously, slow fermentation is beneficial for flavor optimization and reduces the generation of off-flavors.

[0007] Furthermore, the moisture content after air drying is 40-60%, preferably 45%-55%. This water activity (Aw) can meet the water requirements for the growth and reproduction of most beneficial microorganisms, while avoiding excessive growth of soft and rotten bacteria due to excessive moisture content, thus providing the best basic physical conditions for solid-state fermentation.

[0008] Furthermore, the seasoning is an alcoholic beverage with an alcohol content of 50%-55% vol, including any one of sake, rice wine, or fermented rice wine. Spraying alcohol can inhibit some miscellaneous bacteria, purify the fermentation system, provide an initial carbon source for the fermentation strains, and its trace components can also promote the formation of flavor substances.

[0009] Furthermore, the seasoning is edible salt, and the amount of salt added is 4%-6% of the weight of Jerusalem artichoke. Adding salt can maintain the osmotic pressure for fermentation bacteria, further inhibit the growth of Gram-negative bacteria, screen out salt-tolerant beneficial bacteria, and also help water seep out, making the flavor more penetrating and the texture more supple.

[0010] Furthermore, when the fermentation environment temperature is below 15℃, the fermentation time is greater than 40 days. Extending the fermentation time is to ensure that beneficial microorganisms fully complete the degradation of inulin and the accumulation of metabolites under low temperature conditions, so as to ultimately achieve the quality standards and functional enrichment of the fermentation products, while ensuring the stability and safety of the fermentation process.

[0011] Furthermore, the air-drying method can be any one of natural air drying, low-temperature drying, or vacuum drying.

[0012] Furthermore, the Jerusalem artichoke can be cut into any of the following forms: shredded or diced.

[0013] Jerusalem artichoke slices, after being sealed and fermented with wine and salt, have a slightly sweet or slightly salty taste, but are not sour. If the fermentation time is too long, especially after being exposed to the high temperatures of the summer, the taste will become slightly sweet and slightly sour because the sugar source is consumed. The food mentioned includes any one of ordinary food and health food.

[0014] The present invention also provides a fermented Jerusalem artichoke product prepared by the aforementioned Jerusalem artichoke solid-state fermentation technology.

[0015] Furthermore, the Jerusalem artichoke product can be used as a raw material for food processing and inulin extraction. In some embodiments, the flavored food can be Jerusalem artichoke inulin tablets, which can be used as a snack or condiment, with a slightly sweet, slightly spicy and slightly salty taste, and has the function of stabilizing blood sugar.

[0016] Furthermore, the inulin extraction raw material needs to be dried and pulverized at a low temperature below 60°C before inulin extraction.

[0017] The fermented Jerusalem artichoke product obtained by this invention can be used as a food ingredient, utilizing the improved flavor, nutrition, and texture brought about by fermentation, and can be used as a basic raw material for the development of various common foods, including flavored snacks; as a functional ingredient, its enriched inulin, dietary fiber, vitamins, and minerals make it suitable as a core ingredient in the manufacture of health foods or dietary supplements; and as an extraction raw material, it can serve as a high-quality starting material for the subsequent extraction of high-purity inulin and other components.

[0018] In summary, compared with the prior art, the present invention achieves the following technical effects: 1. Minimalist equipment and low energy consumption threshold: No expensive and complicated extraction and purification equipment is required. Fermentation is completed by relying on natural temperature, which can significantly reduce the initial equipment investment and energy consumption in the production process, and precisely meet the industrialization needs of small and medium-sized enterprises.

[0019] 2. Clean label and green environmental protection advantages: The product is natural and rich in original flavor, realizing the high-value utilization of all components of Jerusalem artichoke tuber; the production process has no waste residue and no wastewater discharge, especially eliminating the generation of high-concentration organic wastewater, which not only meets the trend of healthy food consumption, but also significantly reduces the pressure of environmental treatment.

[0020] 3. Simplified process and flexible product form: Based on the aforementioned diverse application pathways, the fermented Jerusalem artichoke semi-finished product provided by this technology exhibits extremely high industrialization flexibility. It can be directly marketed to end-product foods, or used as a functional ingredient or raw material for deep processing, thus opening up the entire industry chain from basic agricultural products to ordinary foods, health foods, and even high-value-added extracts, thereby greatly expanding application scenarios and shortening the downstream product development cycle.

[0021] 4. Balanced cost-effectiveness: With a significant reduction in production costs and process complexity, the polysaccharide yield of this technology is comparable to that of high-efficiency extraction technologies, giving it outstanding market competitiveness. Attached Figure Description

[0022] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present invention and should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0023] Figure 1 This is a schematic diagram of the solid-state fermentation process of Jerusalem artichoke according to the present invention. Detailed Implementation

[0024] To enable those skilled in the art to better understand the present invention, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of the present invention.

[0025] Test method of this invention 1. Sensory Evaluation: The sensory evaluation criteria established using quantitative descriptive analysis are shown in Table 1. Sensory evaluations of the fermented Jerusalem artichokes were conducted according to the scoring criteria. The evaluation team consisted of 10 members, with a male-to-female ratio of 1:1. Members evaluated the solid-state fermented Jerusalem artichoke products under different conditions from four aspects: color, texture, aroma, and taste.

[0026] Table 1 Sensory Evaluation Standards for Jerusalem Artichoke Fermented Products

[0027] 2. The determination of total polysaccharide content in fermented Jerusalem artichoke using ultraviolet-visible absorption spectroscopy (UV) includes the following steps: (1) Preparation of standard: Weigh 5 mg of glucose standard and dilute it to 50 mL with distilled water to obtain a 0.1 mg / mL standard solution; (2) Preparation of sample solution: Weigh 80g of fermented Jerusalem artichoke product, add 500ml of water to extract for 1.5h, filter, concentrate the filtrate to 100ml, add anhydrous ethanol to the alcohol content to 80%, refrigerate at 4℃ overnight, centrifuge at 5000rpm for 10min, take the precipitate, wash with ethanol 3 times, combine the washing liquid and supernatant, take the precipitate, dissolve in water and make up to 50mL in a volumetric flask, dissolve in hot water by sonication, and then take an appropriate volume for dilution.

[0028] (3) Color development method: The phenol-sulfuric acid method is used for color development. Take 0.5 ml of sample, add distilled water to 1 ml, add 1 mL of 5% phenol solution and 5 mL of concentrated sulfuric acid, shake well, let stand for 10 min, keep warm in boiling water bath for 15 min, take it out, cool to room temperature, and measure the absorbance within 60 minutes.

[0029] (4) Wavelength determination: According to the UV-Vis spectrophotometry method of the General Chapter (0401) of Part IV of the 2020 edition of the Chinese Pharmacopoeia, take the reference solution and the test solution respectively, and scan them in the wavelength range of 200-800 nm after color development. Finally, select the wavelength of 487 nm.

[0030] (5) Standard curve plotting: Take 0.1, 0.3, 0.5, 0.7, 0.9, and 1.0 mL of the control samples respectively, place them in 10 mL stoppered test tubes, and add distilled water to 1 mL. Use the corresponding reagents as blank controls, develop the color according to the method described in step (3), and measure the absorbance. Plot a standard curve with glucose concentration as the abscissa and absorbance as the ordinate. The standard curve equation for glucose concentration versus absorbance is Y = 0.7589X + 0.0307(R) 2 = 0.9977, where X is the sugar concentration and Y is the absorbance value.

[0031] (6) Determination of polysaccharide content: The absorbance of the sample to be tested is determined according to the display method in step (3), and the polysaccharide content is calculated based on the obtained standard curve.

[0032] Example 1: Solid-state fermentation of Jerusalem artichoke chips with different moisture contents (1) Select fresh Jerusalem artichokes, wash and slice them, and air-dry the Jerusalem artichoke slices until the moisture content is 30%, 40%, 45%, 50%, 55%, 60%, or 70%.

[0033] (2) Spray the dried Jerusalem artichoke slices with 50% alcohol content, add salt to a concentration of 3%, and stir thoroughly.

[0034] (3) Pack the mixed Jerusalem artichoke slices into a ceramic container, press them down, seal the container opening, and create an anaerobic or facultative anaerobic fermentation environment.

[0035] (4) Place the sealed container in an environment of 20℃ for fermentation. The fermentation time is 40 days. The solid-state fermentation process of Jerusalem artichoke is as follows: Figure 1 As shown.

[0036] (5) After fermentation, the appearance, smell and taste of the fermented Jerusalem artichoke product were evaluated and the content of fermented Jerusalem artichoke polysaccharide was determined by UV method. The test results are shown in Table 2.

[0037] Table 2 Evaluation results of Jerusalem artichoke chips with different moisture contents after fermentation

[0038] As shown in Table 2, the inulin content of fermented Jerusalem artichoke first increased and then decreased with increasing moisture content, reaching its highest level of 76.0 mg / g at 50% moisture content. Inulin dissolution was insufficient below 50% moisture content, while inulin loss increased above 50% due to moisture loss. Sensory evaluation results showed that the color, aroma, appearance, and taste of Jerusalem artichoke products were optimal at 50% moisture content. When the moisture content was above 60% or below 40%, the scores for each sensory indicator decreased to 2.1-3.7 points, manifested as darker color, weaker aroma, irregular appearance, and poorer taste.

[0039] Example 2 Solid-state fermentation of Jerusalem artichoke at different temperatures The difference from Example 1 is that the water content is 50%. The sealed container was placed at 5℃, 10℃, 15℃, 20℃, 25℃ and 30℃. The evaluation results are shown in Table 3.

[0040] Table 3 Evaluation results of solid-state fermented Jerusalem artichoke at different temperatures

[0041] As shown in Table 3, the inulin content of Jerusalem artichoke products first increased and then decreased with rising fermentation temperature, reaching a peak of 76.0 mg / g at 20℃. Below 20℃, microbial metabolism was weak, resulting in insufficient inulin decomposition; above 20℃, microbial metabolism was enhanced, leading to increased inulin decomposition. Sensory evaluation results showed that the color, aroma, appearance, and taste of Jerusalem artichoke products were optimal at 20℃. Below 10℃ or above 25℃, the scores for each sensory indicator dropped to 2.1-3.7, exhibiting characteristics of dull color, weak aroma, irregular appearance, and poor taste.

[0042] In summary, 20℃ is the optimal temperature for solid-state fermentation of Jerusalem artichoke, under which the inulin content and sensory quality are optimal.

[0043] Example 3 Solid-state fermentation of Jerusalem artichoke at different fermentation times The difference from Example 1 is that the water content is 50%, and the fermentation days after sealing are 25, 30, 35, 40, 45, and 50 days. The evaluation results are shown in Table 4.

[0044] Table 4 Evaluation results of solid-state fermented Jerusalem artichoke at different number of days

[0045] As shown in Table 4, the inulin content of fermented Jerusalem artichoke first increased and then decreased with the increase of fermentation days, reaching the highest value at 40 days; fermentation was insufficient at 25 days, resulting in low inulin content; the inulin content remained at a high level from 40 to 45 days; and fermentation was excessive at 50 days, with inulin being further metabolized and decomposed. According to the sensory evaluation results, the color, aroma, appearance, and taste of Jerusalem artichoke products scored 4.3-4.9 points in the 30-45 day range, with the best scores for each indicator at 40 days; the sensory scores dropped to 3.0-3.5 points at 25 and 50 days, indicating dull color, weak aroma, and poor taste.

[0046] In summary, 30-45 days is the suitable period for solid-state fermentation of Jerusalem artichoke, and the inulin content and overall sensory quality are best around 40 days.

[0047] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A Jerusalem artichoke solid-state fermentation technology, characterized in that, After slicing Jerusalem artichokes and air-drying them, spray them with seasonings, mix them well, seal them in a ceramic container, and ferment them at 10-25℃ for 30-45 days to obtain the fermented product; the container can also be any of glass jars or food-grade stainless steel jars.

2. The Jerusalem artichoke solid-state fermentation technology according to claim 1, characterized in that, The moisture content of the dried Jerusalem artichoke is 40-60%, preferably 45%-55%.

3. The Jerusalem artichoke solid-state fermentation technology according to claim 1, characterized in that, The seasoning is an edible wine with an alcohol content of 50%-55% vol.

4. The Jerusalem artichoke solid-state fermentation technology according to claim 1, characterized in that, The seasoning is edible salt, and the amount of salt added is 4%-6% of the weight of Jerusalem artichoke.

5. The Jerusalem artichoke solid-state fermentation technology according to claim 1, characterized in that, When the fermentation environment temperature is below 15℃, the fermentation time is greater than 40 days.

6. The Jerusalem artichoke solid-state fermentation technology according to claim 1, characterized in that, The Jerusalem artichoke drying method can be any one of natural air drying, low-temperature drying, or vacuum drying.

7. The Jerusalem artichoke solid-state fermentation technology according to claim 1, characterized in that, The Jerusalem artichoke can also be cut into shreds or cubes.

8. The fermented Jerusalem artichoke product prepared by the Jerusalem artichoke solid-state fermentation technology according to any one of claims 1-7.

9. The Jerusalem artichoke product according to claim 8, characterized in that, The Jerusalem artichoke product can be used as a raw material for food processing and inulin extraction, and the food includes any one of ordinary food and health food.

10. The Jerusalem artichoke product according to claim 9, characterized in that, The inulin extraction raw materials need to be dried and pulverized at a low temperature below 60℃ before inulin extraction.

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