Hyperspectral monitoring and preparation method of eurotium cristatum fermented gastrodia elata, fermented gastrodia elata product and application

Abstract

The invention belongs to the technical field of hyperspectral intelligent detection, and discloses a hyperspectral monitoring and preparation method of eurotium cristatum fermented gastrodia elata, which comprises the following steps: adjusting the water content of dried gastrodia elata or cutting fresh gastrodia elata into square blocks, placing in a fermentation bottle, sterilizing, inoculating eurotium cristatum spore suspension, uniformly mixing, placing in a constant-temperature incubator, and culturing for 0-12 days; regularly sampling and collecting a hyperspectral image, screening characteristic wavelengths by using a CARS-MLR algorithm, establishing a PLS-DA model, and performing pixel-level prediction and visual mapping on indexes such as gastrodin and p-hydroxybenzyl alcohol; gC-MS (gas chromatography-mass spectrometry) volatile substance analysis and sensory evaluation verify that the horse urine smell is remarkably reduced after fermentation, and pleasant fragrances such as mushroom flower fragrance and mint fragrance are enhanced. According to the method, the content of active ingredients such as polysaccharides and polyphenols is remarkably increased, the flavor of the gastrodia elata is improved, online nondestructive testing and intelligent control in the gastrodia elata fermentation process are achieved, and the fermented gastrodia elata product with low peculiar smell, high activity and enhanced functions is obtained.

Description

Technical Field

[0001] This invention belongs to, but is not limited to, the field of hyperspectral intelligent detection technology, and particularly relates to a hyperspectral monitoring and preparation method of *Gastrodia elata* fermented with *Aspergillus cristatus*, fermented *Gastrodia elata* products and applications. Background Technology

[0002] Gastrodia elata ( Gastrodia elata Gastrodia elata is a traditional and precious Chinese medicinal herb with various physiological functions, including sedation, anti-epileptic effects, memory improvement, antioxidant properties, and blood sugar reduction. It was officially included in the "Food and Drug Substances" list in 2023, indicating its broad application prospects. However, its strong, unpleasant odor, resembling "horse urine," severely limits its acceptance in food and health products.

[0003] Coronavirus ( Eurotium cristatum *Aspergillus cristatus* is a beneficial fungus and a major component of the "golden flower" in Fu brick tea. It possesses the ability to secrete various extracellular enzymes (such as cellulase, protease, and amylase), which can transform the active ingredients in medicinal materials, improving their bioavailability and pharmacological activity. Currently, research on *Aspergillus cristatus* fermentation of *Gastrodia elata* is still in the exploratory stage, and effective monitoring methods for the fermentation process are lacking. Traditional methods mainly rely on offline sampling and biochemical analysis (such as determining polysaccharide and polyphenol content), which suffer from problems such as lag, sample destruction, and inability to reflect the spatial heterogeneity within the fermentation system, leading to unstable quality between fermentation batches and poor process controllability.

[0004] Hyperspectral imaging technology can simultaneously acquire image information and continuous spectral information of the object under test, achieving "image-spectrum integration," which has unique advantages in rapid and non-destructive testing. However, its application to solid-state fermentation processes with complex compositions and dynamic changes in state, especially the online monitoring and control of *Aspergillus cristatus* fermentation of *Gastrodia elata* using hyperspectral imaging technology, has not yet been publicly reported. Summary of the Invention

[0005] The core objective of this invention is to construct a hyperspectral-driven precise control system for solid-state fermentation of *Aspergillus cristatus* and *Gastrodia elata*. By collecting instantaneous spectral data of the surface layer of *Gastrodia elata* in the 400–1000 nm band, the spatial distribution and temporal changes of key indicators such as polysaccharides, reducing sugars, polyphenols, and flavonoids within the matrix are monitored in real time. This achieves non-destructive and non-contact online monitoring, thereby intelligently determining the fermentation endpoint. This maximizes the preservation of the original morphology and microenvironment of *Gastrodia elata*, significantly improving the conversion rate of active ingredients and the consistency of flavor quality.

[0006] The present invention is achieved through the following technical solution: a hyperspectral monitoring and preparation method for fermented Gastrodia elata using Aspergillus cristatus, characterized in that the method uses Aspergillus cristatus as a fungal agent for solid-state fermentation of Gastrodia elata, thereby improving the unpleasant odor of Gastrodia elata and obtaining edible products of fermented Gastrodia elata, including medicinal and edible beverages or meal replacement powders.

[0007] Another objective of this invention is to provide a method for preparing fermented Gastrodia elata products, comprising the following steps: (1) Preparation of *Eurotium cristatum* inoculum; (2) Gastrodia elata fermentation: Gastrodia elata is cut into cubes of about 1 cm, sterilized by high temperature and high pressure, and then added to the suspension of Aspergillus cristatus inoculum under sterile conditions. The mixture is shaken well and placed in a constant temperature incubator for a certain period of time to obtain fermented Gastrodia elata product.

[0008] (3) During the fermentation process, samples are taken regularly to collect spectral image information, extract characteristic wavelengths, and establish a predictive model of active ingredients and functional activities.

[0009] (4) Combine GC-MS analysis of changes in volatile compounds to verify the flavor improvement effect.

[0010] Furthermore, in step (1), the *Aurotriarcha* strain is classified as *Aurotriarcha*, which was obtained from the Flavor Experiment Group of this college and has been identified as this strain, with accession number: M 2022211.

[0011] Further, step (1) involves inoculating the *Eurotium cristatum* strain onto potato dextrose agar medium and purifying it at 28 ℃ for 8-10 days. After maturation, a sample is taken and mixed with bran sterilized at 121 ℃ for 20 min, with a mixing ratio of 10 mycelial cakes per 100 g of bran. The mixture is then cultured at 28 ℃ for 8 days, and subsequently dried in a 45 ℃ oven for 8 h. The powder is then ground into powder, and the spore count concentration is determined using a hemocytometer to be 3.6-4.3 × 10⁻⁶. 6 CFU / mL, store at −20 ℃ for later use.

[0012] Furthermore, the gastrodia tuber is made by soaking fresh or dried gastrodia in water and cutting it into tubers about 1cm in size, with a water content of 70%-90%.

[0013] Furthermore, in step (2), the amount of *Aspergillus cristatus* inoculant added is 1‰ to 2‰ of the total mass of the *Gastrodia elata* tuber, calculated in v / m.

[0014] Furthermore, in step (2), the solid-state fermentation culture conditions are: 28 ℃, constant temperature culture for 2 to 12 days.

[0015] Furthermore, the spectral range is 400–1000 nm, the characteristic wavelengths are selected using the CARS-SPA algorithm, the modeling method is PLSR, and the prediction indicators include polysaccharides, reducing sugars, polyphenols, flavonoids, gastrodin, p-hydroxybenzyl alcohol, and ABTS. +DPPH·, FRAP, α-amylase inhibition rate, α-glucosidase inhibition rate.

[0016] Application of *Aspergillus cristatus* or *Aspergillus cristatus* inoculum in any of the following aspects: A: Removes the unpleasant odor of Gastrodia elata and increases its aromatic components; B: Increase the content of Gastrodia elata polysaccharides, reducing sugars, total flavonoids and / or total polyphenols; C: Enhances the in vitro antioxidant and / or hypoglycemic inhibitory activities of Gastrodia elata; The aforementioned *Aurogonium cristatum* is classified as *Aurogonium cristatum*. Eurotium cristatum Collection number: M2022211.

[0017] Based on the above technical solutions and the technical problems solved, the advantages and positive effects of the technical solution to be protected by this invention are as follows: This invention utilizes solid-state fermentation of Gastrodia elata by *Aspergillus cristatus* for preliminary experiments. After solid-state fermentation, the surface of Gastrodia elata is covered with "golden flowers," the mycelium flowers grow vigorously, the particles are large and plump, and the mycelium flowers have a distinct aroma.

[0018] In this invention, the "horse urine smell" of Gastrodia elata is significantly improved after fermentation with Eurotium cristatum, and it has a special "fungus flower" aroma, a mellow taste, and a unique flavor, which improves its edibility and applicability.

[0019] This invention, through fermentation with *Aspergillus cristatus*, increases the content of total polysaccharides, reducing sugars, total flavonoids, and total polyphenols in *Gastrodia elata*; and enhances the in vitro antioxidant properties of *Gastrodia elata* (DPPH· free radical scavenging rate, ABTS). + Inhibitory activity of free radical scavenging rate and ferric reducing power) and / or in vitro hypoglycemic agents (α-glucosidase and α-amylase).

[0020] This invention provides a method for hyperspectral online guidance of *Aspergillus cristatus* fermentation of *Gastrodia elata*.

[0021] This invention uses *Aspergillus cristatus* as the fermentation strain to obtain a fermented *Gastrodia elata* product, which significantly improves the nutritional value of *Gastrodia elata* and is expected to expand the application of *Gastrodia elata* in food, pharmaceuticals, cosmetics, health products, and other fields.

[0022] The expected benefits and commercial value of the technical solution of this invention after transformation are as follows: This technical solution achieves precise control of the fermentation process of Gastrodia elata and significant improvement of product flavor through solid-state fermentation of Eurotium cristatum combined with hyperspectral intelligent monitoring, and has clear commercialization potential and diversified revenue prospects.

[0023] Gastrodia elata was included in the "Food and Drug Substances" list in 2023, and its market demand in functional foods, health products, and food-medicine homology products continues to grow. However, the inherent "horse urine smell" of Gastrodia elata severely restricts its public acceptance and application scope. This invention significantly improves its flavor, enhances its taste and aroma through fermentation, making it easier to integrate into daily foods, meal replacement powders, solid beverages, tea drinks, and other consumption scenarios, and is expected to open up a multi-billion-dollar functional food and health product market.

[0024] Fermentation not only improves the flavor but also simultaneously increases the content of active ingredients such as polysaccharides, polyphenols, and flavonoids in Gastrodia elata, and enhances its antioxidant and hypoglycemic activities. This gives fermented Gastrodia elata products stronger functional claims and differentiated competitiveness among similar deep-processed Chinese medicinal materials, which can drive the product towards high-end and functional directions and improve its premium pricing power.

[0025] Traditional fermentation relies on manual experience and offline testing, resulting in poor batch consistency. This invention introduces hyperspectral imaging technology to achieve real-time, non-destructive, and spatially visualized monitoring of the key components (such as polysaccharides, polyphenols, and flavonoids) during fermentation, and can intelligently determine the fermentation endpoint based on predictive models. This technology greatly improves process controllability, stability, and automation, providing reliable technical support for large-scale, standardized production, reducing quality control costs, and increasing capacity utilization.

[0026] This system integrates hyperspectral hardware, algorithm models, and fermentation process parameters, and can be packaged as a "Smart Fermentation Process Monitoring Solution" for technology licensing or monitoring services to relevant food and pharmaceutical companies. Furthermore, the *Aspergillus cristatus* inoculum (accession number M 2022211) can also be sold as a dedicated fermentation agent, generating a sustainable revenue stream.

[0027] Fermented Gastrodia elata can be further developed into various end products, such as functional beverages, oral liquids, capsules, and cosmetic additives, extending to the entire health industry chain and creating multi-stage value-added.

[0028] (2) The technical solution of this invention fills a technical gap in the industry both domestically and internationally: The core innovation of this invention lies in the first systematic application of hyperspectral imaging technology to the whole-process monitoring and quality control of *Gastrodia elata* fermented with *Aspergillus cristatus*, filling gaps in existing technologies in multiple dimensions: In the field of fermentation process monitoring, current monitoring of solid-state fermentation processes largely relies on offline sampling and destructive chemical analysis, which cannot achieve real-time, in-situ, and holistic monitoring, nor can it reflect the spatial heterogeneity within the fermentation material. This invention utilizes the "image-spectrum integration" characteristic of hyperspectral imaging to achieve non-destructive, rapid, and spatially visualized monitoring of multiple active ingredients and functional indicators in fermented Gastrodia elata. It is the first time that a hyperspectral-based online monitoring and prediction system has been constructed in the *Aspergillus cristatus*-Gastrodia elata fermentation system, representing a pioneering achievement both domestically and internationally.

[0029] In the field of *Aspergillus cristatus* application research: Although its application in the fermentation of Fu brick tea is mature, its application in the solid-state fermentation of *Gastrodia elata* is still in its early stages. In particular, systematic methods for improving flavor and enhancing activity through process control have not yet been reported. This invention not only clarifies the specific improving effects of this strain on the flavor and components of *Gastrodia elata* (providing detailed data support), but also establishes a complete technical system from inoculant preparation and fermentation process to online monitoring, providing a new technical paradigm for the expanded application of this strain in the deep processing of medicinal and edible homologous substances.

[0030] In the field of intelligent fermentation control, existing fermentation control methods are mostly based on physical parameters such as temperature, humidity, and time, or a few offline biochemical indicators, lacking the ability to respond in real time to dynamic changes in complex component systems. This invention uses the CARS-SPA algorithm to screen characteristic wavelengths and combines them with modeling methods such as PLSR to achieve simultaneous prediction of up to 11 key indicators (including polysaccharides, polyphenols, flavonoids, gastrodin, and various activity indicators). This prediction is then applied to fermentation endpoint determination and process optimization, promoting the intelligent upgrade of solid-state fermentation from "experience-driven" to "data-driven + model prediction," filling the technological gap in multi-indicator fusion prediction and visual control in this field.

[0031] (3) The technical solution of the present invention solves a technical problem that people have long wanted to solve but have never been able to solve successfully: The technical solution provided by this invention successfully overcomes the technical bottleneck of removing the unpleasant flavor of Gastrodia elata: its "horse urine smell" and other unpleasant odors are major obstacles to its edibility and widespread adoption. Traditional physical or chemical deodorization methods easily lead to the loss of active ingredients or introduce safety hazards. Through fermentation with *Aspergillus cristatus*, this invention achieves the biotransformation and optimization of flavor without damaging the overall structure of Gastrodia elata. GC-MS analysis confirms that pleasant "floral" and "minty" aromas are produced after fermentation, while some irritating aldehydes and ketones are reduced or transformed. Sensory evaluation also clearly shows a significant improvement in flavor acceptability. This provides a crucial taste guarantee for Gastrodia elata to transition from a medicinal material to an everyday food, solving a long-standing flavor improvement problem that the industry has been eager to overcome.

[0032] The technical solution provided by this invention addresses a common industry challenge: real-time, non-destructive, and multi-indicator monitoring of solid-state fermentation processes. Solid-state fermentation systems are complex and non-uniform; traditional monitoring methods are lagging, incomplete, and destructive to samples, failing to guide precise control and leading to significant fluctuations in product quality. The industry has long sought technologies capable of reflecting internal changes in the fermentation process in real time. This invention successfully adapts hyperspectral imaging technology to this complex system. By establishing a quantitative relationship model between spectra and various chemical components and functional activities, it achieves, for the first time, multi-dimensional, visualized, and non-invasive online monitoring of the solid-state fermentation process of Gastrodia elata. This allows producers to "see" the fermentation degree and quality distribution in real time, adjust processes promptly, and fundamentally solve the industry-wide problems of "black box" operation and difficult quality control in solid-state fermentation processes.

[0033] (4) The technical solution of the present invention overcomes technical bias: The technical solution provided by this invention overcomes the prejudice that "hyperspectral technology is only suitable for samples with homogeneous surfaces": it is generally believed that hyperspectral imaging is ineffective and noisy in monitoring solid fermentation materials with complex composition, heterogeneous structure, and moist surface. This invention, through innovative spectral preprocessing, a characteristic wavelength screening algorithm (CARS-SPA), and a robust modeling method (PLSR), effectively extracts valid spectral information reflecting changes in internal chemical composition, demonstrating that hyperspectral technology also possesses strong quantitative analysis potential in heterogeneous and dynamically changing solid fermentation systems, thus broadening the application boundaries of this technology.

[0034] The technical solution provided by this invention overcomes the prejudice that "microbial fermentation reduces the content of medicinal materials' unique components": traditional views worry that fermentation may degrade gastrodin, a hallmark component of Gastrodia elata. Data from this invention shows that although the gastrodin content changes during fermentation, the overall spectrum of active ingredients is optimized: the content of components with broad biological activities, such as polysaccharides, polyphenols, flavonoids, and p-hydroxybenzyl alcohol, is significantly increased, while in vitro antioxidant and hypoglycemic functions are enhanced overall. This indicates that *Aspergillus cristatus* fermentation achieves targeted transformation and functional enhancement of components, rather than simple degradation, reversing the one-sided understanding that fermentation may lead to the loss of medicinal components.

[0035] The technical solution provided by this invention overcomes the prejudice that "flavor improvement and functional enhancement are difficult to achieve simultaneously": in food processing, deodorization often results in the loss of functional components. This invention, through a specific strain of *Aspergillus cristatus* and its metabolic characteristics, simultaneously achieves significant flavor improvement and synergistic enhancement of multiple functional activities, demonstrating that through scientific microbial fermentation processes, both flavor and function can be optimized, providing a new approach for the high-value development of food-medicine homologous substances. Attached Figure Description

[0036] Figure 1The images show the state and growth curves of Gastrodia elata at different stages of fermentation by the candidate *Aspergillus cristatus*. A represents the surface morphological characteristics of Gastrodia elata at different fermentation stages, and B represents the growth curves of different isolated strains.

[0037] Figure 2 A standard curve for determining the polysaccharide concentration of glucose.

[0038] Figure 3 A standard curve for determining the reducing sugar concentration in glucose assays.

[0039] Figure 4 This is a standard curve for the determination of rutin concentration.

[0040] Figure 5 This is the standard curve for the determination of gallic acid concentration.

[0041] Figure 6 This is a graph showing the antioxidant activity curves of Gastrodia elata before and after fermentation.

[0042] Figure 7 The graph shows the hypoglycemic activity curves of Gastrodia elata before and after fermentation.

[0043] Figure 8 The spectral reflectance curves of samples pretreated at different stages of fermentation are shown.

[0044] Figure 9 Regression lines were used to predict the polysaccharide content and DPPH· free radical scavenging rate of Gastrodia elata samples at different fermentation stages.

[0045] Figure 10 Based on the orthogonal experimental results of the process based on the PLS-DA model, the overall scores of four active ingredients—polysaccharides, reducing sugars, polyphenols, and flavonoids—were comprehensively evaluated and visualized according to three score ranges: 40–50, 60, and 70–80.

[0046] Figure 11 Visualization of polysaccharide content at three fermentation stages: 0d, 6d, and 12d.

[0047] Figure 12 The graph shows the types and percentage contents of volatile substances in *Gastrodia elata* fermented by *Aspergillus cristatus*, as determined by HS-SPME-GC-MS.

[0048] Figure 13 Sensory evaluation diagram of the aroma of Gastrodia elata fermentation liquid. Detailed Implementation

[0049] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0050] This invention provides a hyperspectral monitoring and preparation method for fermented Gastrodia elata using *Aspergillus cristatus*. The method uses *Aspergillus cristatus* as the inoculum for solid-state fermentation of Gastrodia elata, thereby improving the unpleasant odor of the fermented Gastrodia elata and obtaining edible products from it, including medicinal and edible beverages or meal replacement powders.

[0051] Another objective of this invention is to provide a method for preparing fermented Gastrodia elata products, comprising the following steps: (1) Preparation of *Eurotium cristatum* inoculum; (2) Gastrodia elata fermentation: Gastrodia elata is cut into cubes of about 1 cm, sterilized by high temperature and high pressure, and then added to the suspension of Aspergillus cristatus inoculum under sterile conditions. The mixture is shaken well and placed in a constant temperature incubator for a certain period of time to obtain fermented Gastrodia elata product.

[0052] (3) During the fermentation process, samples are taken regularly to collect spectral image information, extract characteristic wavelengths, and establish a predictive model of active ingredients and functional activities.

[0053] (4) Combine GC-MS analysis of changes in volatile compounds to verify the flavor improvement effect.

[0054] Furthermore, in step (1), the *Aurorus cristatus* strain is classified and named *Aurorus cristatus*. This strain was obtained from the Flavor Experiment Group of this college and has been identified as this strain. Its accession number is M 2022211, its depositary institution is the China Center for Type Culture Collection, and its deposit date is March 7, 2022. Its classification name is *Aurorus cristatus* GY, *Ecgy*. Eurotium cristatum GY, Ecgy, Address of the Preservation Unit: No. 299, Bayi Road, Wuchang District, Wuhan City, Hubei Province.

[0055] Further, step (1) involves inoculating the *Eurotium cristatum* strain onto potato dextrose agar medium and purifying it at 28 ℃ for 8-10 days. After maturation, a sample is taken and mixed with bran sterilized at 121 ℃ for 20 min, with a mixing ratio of 10 mycelial cakes per 100 g of bran. The mixture is then cultured at 28 ℃ for 8 days, and subsequently dried in a 45 ℃ oven for 8 h. The powder is then ground into powder, and the spore count concentration is determined using a hemocytometer to be 3.6-4.3 × 10⁻⁶. 6 CFU / mL, store at −20 ℃ for later use.

[0056] Furthermore, the gastrodia tuber is made by soaking fresh or dried gastrodia in water and cutting it into tubers about 1cm in size, with a water content of 70%-90%.

[0057] Furthermore, in step (2), the amount of *Aspergillus cristatus* inoculant added is 1‰ to 2‰ of the total mass of the *Gastrodia elata* tuber, calculated in v / m.

[0058] Furthermore, in step (2), the solid-state fermentation culture conditions are: 28 ℃, constant temperature culture for 2 to 12 days.

[0059] Furthermore, the spectral range is 400–1000 nm, the characteristic wavelengths are selected using the CARS-SPA algorithm, the modeling method is PLSR, and the prediction indicators include polysaccharides, reducing sugars, polyphenols, flavonoids, gastrodin, p-hydroxybenzyl alcohol, and ABTS. + DPPH·, FRAP, α-amylase inhibition rate, α-glucosidase inhibition rate.

[0060] Application of *Aspergillus cristatus* or *Aspergillus cristatus* inoculum in any of the following aspects: A: Removes the unpleasant odor of Gastrodia elata and increases its aromatic components; B: Increase the content of Gastrodia elata polysaccharides, reducing sugars, total flavonoids and / or total polyphenols; C: Enhances the in vitro antioxidant and / or hypoglycemic inhibitory activities of Gastrodia elata; The *Eocybe* species was classified as *Eocybe* GY. Eurotium cristatum GY, Ecgy, Accession No.: M 2022211, Depository Institution: China Center for Type Culture Collection, Deposit Date: March 7, 2022, Address of Depository Institution: No. 299, Bayi Road, Wuchang District, Wuhan City, Hubei Province.

[0061] This invention first addresses the biotransformation mechanism by utilizing *Aspergillus cristatus*, a fungus with established applications in the food and fermentation fields. Under solid-state fermentation conditions, it secretes a variety of hydrolytic and redox-related enzyme systems, such as polysaccharide-degrading enzymes, phenolic invertases, and enzymes related to amino acid and lipid metabolism. These enzymes act on the polysaccharides, phenols, and aromatic precursors in *Gastrodia elata* tubers. On one hand, they promote the release and structural modification of macromolecular active ingredients, improving the bioavailability of polysaccharides, polyphenols, flavonoids, and characteristic components such as gastrodin and p-hydroxybenzyl alcohol. On the other hand, by regulating volatile metabolic pathways, they reduce or transform aldehydes, ketones, and irritating small molecules that cause unpleasant odors, thereby improving the flavor and enhancing the functional properties of *Gastrodia elata*.

[0062] Secondly, in terms of process monitoring principles, the physicochemical composition, structural state, and metabolite distribution of the Gastrodia elata matrix continuously change with cultivation time during fermentation. These changes are reflected in the absorption, reflection, and scattering characteristics of the sample in the visible-near-infrared range (400–1000 nm). Hyperspectral imaging technology achieves holistic and non-destructive detection of fermented Gastrodia elata by simultaneously acquiring spatial and continuous spectral information. Competitive adaptive reweighted sampling (CARS) and continuous projection algorithm (SPA) are used to screen characteristic wavelengths highly correlated with key chemical components, effectively eliminating redundant information and noise interference, and highlighting spectral features related to active ingredients and antioxidant and hypoglycemic functions.

[0063] Furthermore, in terms of quantitative modeling and prediction mechanisms, partial least squares regression (PLSR) is employed to correlate the selected characteristic spectral variables with physicochemical detection and functional activity data. This model can extract latent factors under multivariate and collinear conditions, enabling the analysis of polysaccharides, reducing sugars, polyphenols, flavonoids, and ABTS. + The simultaneous prediction of the antioxidant capacity of DPPH· and FRAP and the inhibitory activities of α-amylase and α-glucosidase reveals the intrinsic relationship between spectral response and fermentation quality evolution.

[0064] Finally, GC-MS was used to verify the changes in the composition of volatile compounds before and after fermentation, providing chemical support for the hyperspectral prediction results and forming a closed-loop technology system of mutual verification between microbial regulation, spectroscopic characterization, and chemical verification. Overall, this invention combines bio-fermentation modification with intelligent hyperspectral monitoring to achieve visualized, predictable, and optimizable control of the Gastrodia elata fermentation process, providing reliable scientific support for the industrial-scale preparation of high-quality fermented Gastrodia elata functional foods.

[0065] Evidence related to the technical effects and significant technical advancements achieved by the embodiments of the present invention: The growth curve of *Aurogonium cristatum* provided in this embodiment of the invention is plotted as follows: 2g of *Aurogonium cristatum* fermentation agent (M fermentation agent: M water = 1:10) is weighed in a sterile laminar flow hood. 1 mL of the bacterial culture is inoculated into 100 mL of PDB medium and cultured in a 28 ℃ constant temperature shaker for 12 days. Figure 1The growth curve of *Aspergillus cristatus* in PDB medium (expressed as dry weight) shows the following: Initial growth (2-4 days): During the first 4 days of the experiment, the wet weight of the mycelium increased slowly, possibly due to the bacteria adapting to the culture environment and undergoing initial cell division and growth. Logarithmic growth phase (4-8 days): From day 4 to day 8, the wet weight of the mycelium increased significantly, indicating that the bacteria entered the logarithmic growth phase, the fastest growth stage of the microorganism, with rapid cell division and rapid biomass accumulation. Stationary phase (8-12 days): After day 8, although the growth rate slowed down, the wet weight of the mycelium continued to increase, indicating that the bacteria may have entered the stationary phase. At this time, the growth rate began to decline because nutrients may have begun to be depleted or metabolic waste may have begun to accumulate. The growth curve shows that the *Aspergillus cristatus* strain exhibited good activity during the fermentation of *Gastrodia elata* in this invention, indicating that *Aspergillus cristatus* can quickly adapt to and utilize the nutrients in *Gastrodia elata* during fermentation, promoting its growth and metabolic processes.

[0066] (1) Inoculation of Gastrodia elata with Eurotium cristatum: Gastrodia elata with a moisture content of 70% was cut into pieces of about 1 cm, and 10 g was weighed and placed into a 100 mL Erlenmeyer flask. After autoclaving at 121 °C for 20 min and cooling, 100 μL of the bacterial suspension from Example 1 (spore count concentration of 3.6-4.3 × 10⁻⁶) was inoculated in a clean bench. 6 The bacterial suspension (CFU / mL) and Gastrodia elata were mixed and placed in a 28℃ biochemical incubator for solid-state fermentation for 8 days.

[0067] (2) Inoculation of Gastrodia elata with *Aspergillus cristatus*: Gastrodia elata with a moisture content of 80% was cut into pieces approximately 1 cm in size, and 10 g was weighed and placed into a 100 mL Erlenmeyer flask. After autoclaving at 121 °C for 20 min and cooling, 100 μL of the bacterial suspension from Example 1 (spore count concentration of 3.6-4.3 × 10⁻⁶) was inoculated in a clean bench. 6 The bacterial suspension (CFU / mL) and Gastrodia elata were mixed and placed in a 28 ℃ biochemical incubator for solid-state fermentation for 8 days.

[0068] (3) Inoculation of Gastrodia elata with *Aspergillus cristatus*: Gastrodia elata with a water content of 90% was cut into pieces of about 1 cm, and 10 g was weighed and placed into a 100 mL Erlenmeyer flask. After autoclaving at 121 °C for 20 min and cooling, 100 μL of the bacterial suspension from Example 1 (spore count concentration of 3.6-4.3 × 10⁻⁶) was inoculated in a clean bench. 6 The bacterial suspension (CFU / mL) and Gastrodia elata were mixed and placed in a 28℃ biochemical incubator for solid-state fermentation for 8 days.

[0069] (4) Inoculation of Gastrodia elata with *Aspergillus cristatus*: Cut Gastrodia elata with a moisture content of 80% into pieces of about 1 cm, and weigh 10 g and put them into a 100 mL Erlenmeyer flask. After autoclaving at 121 °C for 20 min, and cooling, inoculate 200 μL of the bacterial suspension from Example 1 (spore count concentration of 3.6-4.3 × 10⁻⁶) in a clean bench. 6 The bacterial suspension (CFU / mL) and Gastrodia elata were mixed and placed in a 28 ℃ biochemical incubator for solid-state fermentation for 8 days.

[0070] (5) Inoculation of Gastrodia elata with *Aspergillus cristatus*: Cut Gastrodia elata with a moisture content of 80% into pieces of about 1 cm, and weigh 10 g and put them into a 100 mL Erlenmeyer flask. After autoclaving at 121 °C for 20 min, and cooling, inoculate 200 μL of the bacterial suspension from Example 1 (spore count concentration of 3.6-4.3 × 10⁻⁶) in a clean bench. 6 The bacterial suspension (CFU / mL) and Gastrodia elata were mixed and placed in a 28℃ biochemical incubator for solid-state fermentation for 10 days.

[0071] Inoculation of Gastrodia elata with *Aspergillus cristatus*: Gastrodia elata with a moisture content of 80% was cut into pieces approximately 1 cm in size, and 10 g was weighed and placed into a 100 mL Erlenmeyer flask. After autoclaving at 121 °C for 20 min and cooling, 200 μL of the bacterial suspension from Example 1 (spore count concentration of 3.6-4.3 × 10⁻⁶) was inoculated in a clean bench. 6 The bacterial suspension (CFU / mL) and Gastrodia elata were mixed and placed in a 28 ℃ biochemical incubator for solid-state fermentation for 12 days.

[0072] The prepared Gastrodia elata samples were subjected to the following measurements: 1. Determination of total polysaccharide content of *Aspergillus cristatus* before and after fermentation The total polysaccharide content was determined using the phenol-sulfuric acid colorimetric method. 2. Determination of reducing sugar content before and after fermentation of *Aspergillus cristatus* The reducing sugar content was determined using the DNS (3,5-dinitrosalicylic acid) colorimetric method. 3. Determination of total polyphenol content before and after *Aspergillus cristatus* fermentation The total polyphenol content was determined using the Folin-Ciocalteu colorimetric method. 4. Determination of total flavonoid content before and after fermentation of *Aspergillus cristatus* The total polyphenol content was determined using the sodium nitrite-aluminum nitrate-sodium hydroxide complexation colorimetric method. 5. In vitro antioxidant activity assay Determination of DPPH· free radical scavenging rate and ABTS of Gastrodia elata before and after fermentation with *Aspergillus cristatus* + Free radical scavenging rate and iron reducing power 6. Determination of in vitro blood glucose lowering Determining the inhibition rate of Gastrodia elata on α-amylase and α-glucosidase activities before and after fermentation with *Aspergillus cristatus*. 7. Determination of volatile components Volatile components of Gastrodia elata before and after fermentation with *Aspergillus cristatus* were determined by HS-SPME-GC-MS. Sample preparation of Gastrodia elata: After fermentation, Gastrodia elata was dried in a constant temperature incubator at 50 ℃, crushed with a pulverizer, and passed through a 60-mesh sieve. 0.10 g of Gastrodia elata powder sample was accurately weighed, and 10 mL of distilled water was added. Extraction was performed using ultrasonic extraction with parameters set at a frequency of 40 kHz and a power of 800 W at 30 ℃ for 30 min. The extract was centrifuged at 4000 rpm for 10 min, and the supernatant was collected and brought to a final volume of 10 mL for analysis. For flavonoid determination, 10 mL of 70% ethanol solution was used for extraction.

[0073] Based on the measured values ​​of polysaccharides, reducing sugars, polyphenols, flavonoids, gastrodin, p-hydroxybenzyl alcohol, and three antioxidant indicators, as well as two blood sugar-lowering indicators, a PLS-DA model was established to predict the various indicators at different stages.

[0074] Twenty sensory evaluators were invited to evaluate and score the tea soup made from Gastrodia elata at different stages of fermentation. The samples with different scores were then visualized and analyzed using the collected hyperspectral images.

[0075] Table 1. Verification of active ingredients and functions before and after fermentation.

[0076] index Before fermentation (0d) After fermentation (10 days) Increase multiplier Polysaccharides (mg / g) 330.02±8.55 542.24±5.5 ↑1.64 Reducing sugar (mg / g) 202.65±5.56 344.01±7.82 ↑1.70 Polyphenols (mg / g) 12.17±2.24 49.21±3.75 ↑4.04 Flavonoids (mg / 10g) 15.5±2.99 119.36±5.96 ↑7.70 Gastrodin (mg / g) 2.62±0.07 1.55±0.08 ↓0.59 p-Hydroxybenzyl alcohol (mg / g) 0.26±0.01 1.07±0.02 ↑4.12 DPPH clearance rate (%) 26.31±1.32 69.3±3.88 ↑2.63 <![CDATA[ABTS + Clearance rate (%) 64.53±2.9 98.24±4.22 ↑1.52 <![CDATA[Ferric reducing antioxidant power ( µ mol Fe 2+ / mL)]]> 19.26±1.44 52.94±3.97 ↑2.74 α-Amylase inhibition rate (%) 41.25±2.76 60.67±4.85 ↑1.47 α-glucosidase inhibition rate (%) 24.45±1.81 39.87±2.95 ↑1.63 Table 2 shows a comparison of volatile substances with OAV>1 before and after fermentation.

[0077]

[0078] Example 1 Fresh Gastrodia elata was selected, washed, and soaked until the moisture content was 80%. It was then cut into tubers with a side length of 1 cm, sterilized under high temperature and high pressure, and cooled for later use. A suspension of *Aspergillus cristatus* (preservation number M 2022211) was prepared and added to the treated tubers at a ratio of 1‰ of the total mass of Gastrodia elata. After shaking well, the mixture was placed in a constant temperature incubation environment and solid-state fermentation was carried out at 28 degrees Celsius for 6 days to obtain fermented Gastrodia elata samples.

[0079] During fermentation, samples were subjected to hyperspectral imaging once daily, with the spectral range set from 400 to 1000 nanometers. After preprocessing the acquired spectral data, characteristic wavelengths related to polysaccharide and polyphenol content were extracted, and a predictive model was constructed to achieve real-time monitoring of changes in active ingredients during fermentation. The results showed that this method can stably predict the increasing trend of polysaccharide and polyphenol content in fermented Gastrodia elata.

[0080] Example 2 Dried Gastrodia elata was selected as raw material and soaked in water to restore its moisture content to 75%. The cutting method was the same as in Example 1, and sterilization was completed. *Aspergillus cristatus* inoculant was added at a ratio of 2‰ of the total mass of Gastrodia elata, and then the mixture was placed under constant temperature incubation conditions for solid-state fermentation. The fermentation temperature was maintained at 28 degrees Celsius, and the incubation time was set to 10 days, resulting in a deeply fermented Gastrodia elata sample.

[0081] Throughout the fermentation cycle, spectral images of the samples were acquired on days 2, 5, and 10. Key spectral variables were extracted using a characteristic wavelength screening algorithm, and predictive models for reducing sugar and flavonoid content were established. Comparison with physicochemical test results showed good consistency between the model predictions and measured values, validating the applicability of the hyperspectral monitoring method at different fermentation stages.

[0082] Example 3 Based on Example 1, the preparation process of *Aspergillus cristatus* inoculant was applied and verified. The purified and mature strain was mixed with sterilized wheat bran, cultured, and then dried to produce a powdered inoculant for solid-state fermentation of *Gastrodia elata*. The powder was inoculated into sterilized *Gastrodia elata* tubers at a dosage of 1‰ and cultured at 28°C for 8 days to obtain fermented *Gastrodia elata* samples.

[0083] Hyperspectral imaging technology was used to monitor samples on day 4 and day 8 of fermentation, and the contents of gastrodin and p-hydroxybenzyl alcohol were measured simultaneously. The results showed that the trend of the model prediction values ​​and the actual measured values ​​was consistent, indicating that the inoculant prepared based on wheat bran carrier is also suitable for hyperspectral monitoring and quality control.

[0084] Example 4 The volatile components of the Gastrodia elata samples obtained from fermentation in Example 1 were analyzed. Samples were taken before and after fermentation, and the composition of volatile compounds in the samples was determined by gas chromatography-mass spectrometry to obtain flavor characteristic spectra.

[0085] The analysis results showed that the content of some pungent odor-related compounds decreased after fermentation, while the relative content of aroma-characteristic alcohols and esters increased. These changes are consistent with the fermentation process reflected by hyperspectral monitoring, indicating that *Aspergillus cristatus* fermentation has a clear effect on improving the flavor of *Gastrodia elata*.

[0086] Example 5 Using the fermented Gastrodia elata obtained in Example 2 as an example, the functional activity was further verified. The fermented Gastrodia elata sample was dried and pulverized to prepare sample powder for testing, and compared with the unfermented Gastrodia elata sample.

[0087] ABTS levels in the samples were determined by in vitro antioxidant assay. + The antioxidant capacity of fermented Gastrodia elata samples was significantly higher than that of unfermented samples, and the hyperspectral prediction model could also reflect the enhancing trend of this functional activity.

[0088] Example 6 The fermented Gastrodia elata sample obtained in Example 1 was used to further test its hypoglycemic activities. The sample extract was used to determine the in vitro activity of amylase and glucosidase inhibitors, and compared with the unfermented Gastrodia elata sample.

[0089] Experimental results showed that fermented Gastrodia elata had a significantly higher inhibitory capacity against the two enzymes mentioned above than unfermented Gastrodia elata, and the inhibition rate had a good correlation with the output of the hyperspectral prediction model, verifying the correlation between fermentation and functional activity enhancement.

[0090] Example 7 The fermented Gastrodia elata obtained in Example 1 was further processed into a meal replacement powder product. After being dried at low temperature and pulverized, the fermented Gastrodia elata was directly made into a powder product for use in instant food preparation.

[0091] Sensory evaluation and physicochemical analysis of the meal replacement powder product showed that its odor irritation was significantly reduced, and it had a milder fermented aroma, while retaining a high level of active ingredients, indicating that the fermentation method is suitable for functional food processing.

[0092] Example 8 The fermented Gastrodia elata sample obtained in Example 2 was prepared as a beverage ingredient. It was then pulverized, dissolved, and subjected to simple filtration to form a drinkable product.

[0093] The test results show that the flavor of the beverage raw material is stable during storage, and the hyperspectral monitoring model can be used to guide the selection of the optimal fermentation endpoint, providing a basis for the large-scale preparation of beverage products.

[0094] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any modifications, equivalent substitutions, and improvements made by those skilled in the art within the scope of the technology disclosed in the present invention, and within the spirit and principles of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A method for hyperspectral monitoring and preparation of *Gastrodia elata* fermented with *Aspergillus cristatus*, characterized in that, This method uses *Aspergillus cristatus* as an inoculum for solid-state fermentation of *Gastrodia elata*, thereby improving the unpleasant odor of *Gastrodia elata* and obtaining fermented *Gastrodia elata* edible products, including medicinal and edible beverages or meal replacement powders.

2. A method for preparing a fermented Gastrodia elata product, characterized in that, Includes the following steps: (1) Preparation of *Eurotium cristatum* inoculum; (2) Gastrodia elata fermentation: Gastrodia elata is cut into cubes of about 1 cm, sterilized by high temperature and high pressure, and then added to the suspension of Aspergillus cristatus inoculum under sterile conditions. The mixture is shaken well and placed in a constant temperature incubator for a certain period of time to obtain fermented Gastrodia elata product. (3) During the fermentation process, samples are taken regularly to collect spectral image information, extract characteristic wavelengths, and establish a predictive model of active ingredients and functional activities; (4) Combine GC-MS analysis of changes in volatile compounds to verify the flavor improvement effect.

3. The method for preparing fermented Gastrodia elata product according to claim 2, characterized in that, In step (1), the *Aurotriarcha* strain is classified as *Aurotriarcha*. This strain was obtained from the Flavor Experiment Group of this college and has been identified as this strain. Its accession number is M 2022211.

4. The method for preparing fermented Gastrodia elata product according to claim 2, characterized in that, Step (1) involves inoculating *Eurotium cristatum* strain onto potato dextrose agar medium and purifying it at 28 ℃ for 8-10 days. After maturation, samples are taken and mixed with bran sterilized at 121 ℃ for 20 min, with a mixing ratio of 10 mycelial cakes per 100 g of bran. The mixture is then cultured at 28 ℃ for 8 days, and subsequently dried in a 45 ℃ oven for 8 hours. The powder is then ground, and the spore count concentration is determined using a hemocytometer to be 3.6-4.3 × 10⁻⁶. 6 CFU / mL, store at −20 ℃ for later use.

5. The method for preparing fermented Gastrodia elata product according to claim 2, in step (2), the Gastrodia elata tuber is made by soaking fresh or dried Gastrodia elata in water and cutting it into tubers of about 1 cm, wherein the water content of the Gastrodia elata is 70%-90%.

6. The method for preparing fermented Gastrodia elata product according to claim 2, characterized in that, In step (2), the amount of *Aspergillus cristatus* inoculant added is 1‰ to 2‰ of the total mass of the *Gastrodia elata* tuber, calculated in v / m.

7. The method for preparing fermented Gastrodia elata product according to claim 1, characterized in that, In step (2), the solid-state fermentation culture conditions are: 28 ℃, constant temperature culture for 2 to 12 days.

8. The method for preparing fermented Gastrodia elata product according to claim 3, characterized in that, The spectral range is 400–1000 nm, and the characteristic wavelengths are selected using the CARS-SPA algorithm. The modeling method is PLSR, and the prediction indicators include polysaccharides, reducing sugars, polyphenols, flavonoids, gastrodin, p-hydroxybenzyl alcohol, and ABTS. + DPPH·, FRAP, α-amylase inhibition rate, α-glucosidase inhibition rate.

9. The fermented Gastrodia elata product prepared by the preparation method according to any one of claims 6-9.

10. Application of *Aspergillus cristatus* or *Aspergillus cristatus* inoculants in any of the following aspects: A: Removes the unpleasant odor of Gastrodia elata and increases its aromatic components; B: Increase the content of Gastrodia elata polysaccharides, reducing sugars, total flavonoids and / or total polyphenols; C: Enhances the in vitro antioxidant and / or hypoglycemic inhibitory activities of Gastrodia elata; The aforementioned *Aurogonium cristatum* is classified as *Aurogonium cristatum*. Eurotium cristatum Collection number: M2022211.

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