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CN-122017141-A - Multidimensional analysis and evaluation method for distiller's yeast quality

CN122017141ACN 122017141 ACN122017141 ACN 122017141ACN-122017141-A

Abstract

The invention discloses a multi-dimensional analysis and evaluation method for distiller's yeast quality, which comprises the following steps of S1, carrying out sensory evaluation on distiller's yeast, calculating the sensory evaluation total score of the distiller's yeast, S2, carrying out physicochemical property measurement on the distiller's yeast, measuring two core physicochemical indexes of moisture content, volatile component content and color level of the distiller's yeast, S3, carrying out biochemical property measurement on the distiller's yeast, measuring the liquefaction force of the distiller's yeast, quantifying the biochemical catalysis performance of the distiller's yeast, S4, screening through GC-MS analysis and a principal component analysis method, determining the characteristic markers of the distiller's yeast quality, optimizing the extraction process of the characteristic markers by adopting a Box-Behnken response surface method, determining the optimal extraction process condition, S5, extracting flavor compounds in the distiller's yeast under the optimal extraction condition, carrying out qualitative and quantitative analysis on the flavor compounds in the distiller's yeast, calculating the relative proportion and content of the characteristic markers and the compounds, and S6, calculating the comprehensive weight score of the distiller's yeast by adopting a scoring algorithm.

Inventors

  • LING XU
  • JIN ZHIXIONG
  • GE ZHENKAI
  • CHEN QIANQIAN

Assignees

  • 湖北医药学院

Dates

Publication Date
20260512
Application Date
20260211

Claims (10)

  1. 1. A multidimensional analysis and evaluation method for distiller's yeast quality is characterized by comprising the following steps: s1, carrying out sensory evaluation on distiller's yeast, and calculating the sensory evaluation total score of the distiller's yeast; s2, measuring physicochemical properties of the distiller's yeast, and measuring two core physicochemical indexes of moisture, volatile component content and color level of the distiller's yeast; S3, measuring biochemical properties of the distiller's yeast, measuring liquefaction force of the distiller's yeast, and quantifying biochemical catalytic properties of the distiller's yeast; S4, screening by a GC-MS analysis and principal component analysis method, determining characteristic markers of distiller's yeast quality, optimizing the extraction process of the characteristic markers by a Box-Behnken response surface method, and determining optimal extraction process conditions; S5, extracting flavor compounds in the distiller's yeast under the optimal extraction condition, carrying out qualitative and quantitative analysis on the flavor compounds in the distiller's yeast, and calculating the relative proportion and content of the characteristic markers and the flavor compounds; and S6, calculating the comprehensive quality score of the distiller's yeast by adopting a weight scoring algorithm.
  2. 2. The multidimensional analysis and evaluation method for distiller 'S yeast quality as recited in claim 1, wherein the distiller' S yeast is yellow wine small yeast, and step S1 comprises the following steps: S101, collecting original descriptors of distiller's yeast, calculating the frequency F and the intensity I of each descriptor by adopting an approximate estimation method, calculating a contribution index M= v (F multiplied by I), screening the descriptors with M values larger than a preset threshold, and establishing a special sensory description word stock of distiller's yeast with three dimensions of appearance, aroma and texture after merging and arrangement; S102, observing the color and luster of hypha on the surface of distiller's yeast, the uniformity of hypha coverage and the condition of surface cracks, and quantitatively evaluating the appearance by adopting a 0-10 score evaluation method; s103, after longitudinal cutting along the distiller's yeast center, observing the mycelium form, the color and the pore condition of the section, and quantitatively evaluating the section form by adopting a 0-10 score method; S104, randomly selecting a plurality of detection points by using a vernier caliper, measuring the thickness of an unfermented raw starch layer on the surface layer of the distiller's yeast, taking an average value as a yeast thickness evaluation basis, and quantitatively evaluating the thickness of the yeast by adopting a 0-10 score evaluation method S105, smelling the aroma of the section of the distiller's yeast, distinguishing the purity of the aroma, the intensity of the aroma and the existence of foreign flavor according to a sensory description word stock special for the distiller's yeast, and quantitatively evaluating the aroma characteristics by adopting a 0-10 score evaluation method; and S106, adding the four dimension scores, and checking consistency among the evaluators by adopting a consistency ratio CR, wherein the evaluation result is considered to be reliable when CR is less than 0.1.
  3. 3. The method for multidimensional analysis and evaluation of distiller' S yeast quality according to claim 1, wherein in step S2, the measurement of moisture and volatile component content specifically includes the steps of: S201, taking a clean and dried glass dish with constant weight, weighing the glass dish and marking the mass as m 0 ; s202, accurately adding a distiller's yeast sample, weighing the total mass of a glass dish and the sample, and recording as m 1 ; s203, placing the glass dish filled with the distiller's yeast sample in a drying oven at 100+/-5 ℃, drying to constant weight, weighing the total mass of the glass dish and the dried sample at the moment, and recording as m 2 ; S204, calculating the content of moisture and volatile components according to a formula W= (m 1 - m 2 ) / (m 1 - m 0 ) multiplied by 100%, wherein W is the content of the moisture and the volatile components, m 0 is the mass of the glass dish, m 1 is the total mass of the sample and the glass dish before drying, and m 2 is the total mass of the sample and the glass dish after drying; And S205, weighing the distiller's yeast samples with the accuracy of 0.0001 g, setting 3 parallel samples for each distiller's yeast sample, taking the average value as a final measurement result, and ensuring the reliability of measurement data.
  4. 4. The method for multidimensional analysis and evaluation of distiller' S yeast quality according to claim 1, wherein in step S2, the measurement of the color level specifically includes the steps of: s211, precisely weighing a distiller's yeast powder sample m, adding 70% ethanol as an extraction solvent, and fixing the volume to V after extraction; s212, placing the extracting solution in a water bath at 60 ℃ for constant temperature extraction for 2h, cooling to room temperature, centrifuging to obtain supernatant, and diluting F times as required; S213, taking 70% ethanol as a blank control, and measuring absorbance A of the diluted supernatant at the maximum absorption wavelength of an ultraviolet-visible spectrophotometer; S214, calculating a color level according to a formula L= (FxA x V)/m, wherein L is an absorbance value of a unit mass sample, F is a dilution multiple of supernatant fluid, V is a constant volume of an extracting solution, and m is the mass of a distiller's yeast powder sample; And S215, setting 3 parallel samples for each sample, taking an average value as a final color level result, and reducing detection errors.
  5. 5. The multi-dimensional analysis and evaluation method of distiller' S yeast quality according to claim 1, wherein step S3 specifically comprises the steps of: S301, calculating and weighing a distiller's yeast sample corresponding to a certain weight of absolute dry distiller's yeast according to the measured moisture and volatile component content W of the distiller's yeast, adding the distiller's yeast sample into distilled water and acetic acid-sodium acetate buffer with pH of 4.6, soaking for 3h under the constant temperature condition of 40 ℃, filtering after soaking is completed, and collecting filtrate as enzyme solution for later use; s302, taking 2% soluble starch solution, placing the soluble starch solution in a constant-temperature water bath at 35 ℃ to be preheated to constant temperature, adding the enzyme solution into the preheated starch solution, immediately starting the reaction in a timing way, sampling at regular time in the reaction process, dripping dilute iodine solution to observe the color change of the solution, and recording the reaction time T when the color of the solution is close to the color of the dilute iodine solution; s303, calculating the liquefying force according to a formula Lq=24/T, wherein the liquefying force unit is g/(g.h), T is the reaction time, and 24 is a conversion coefficient; S304, determining saccharification rate and alcohol generation rate of different liquefaction force distiller's yeast in the process of fermenting the yellow wine, and establishing an association equation of the liquefaction force Lq and the fermentation efficiency eta of the yellow wine, wherein eta=alpha×ln (Lq) +beta, alpha and beta are regression coefficients, and the association coefficient R2 is more than or equal to 0.90, so as to predict the brewing performance of the distiller's yeast.
  6. 6. The method for multi-dimensional analysis and evaluation of distiller ' S yeast quality according to claim 1, wherein in step S4, yellow wine small yeast with different quality grades which is primarily divided by sensory and core physicochemical indexes is taken as a research object, the volatile component spectrums of the yellow wine small yeast with different quality grades are analyzed by GC-MS, characteristic variables are extracted by adopting a principal component analysis method, the correlation coefficient r of each compound and the distiller ' S yeast quality grade is calculated, the compound with the correlation coefficient |r| being more than or equal to 0.85 and the variation coefficient CV between different quality grades being more than or equal to 30% is selected as a candidate index, and palmitic acid is determined to be a characteristic marker of distiller ' S yeast quality by comparison.
  7. 7. The method for multidimensional analysis and evaluation of distiller' S yeast quality according to claim 1, wherein in step S4, a Box-Behnken response surface design method is adopted to optimize the extraction process of palmitic acid, extraction time, extraction temperature and feed liquid ratio are selected as three key investigation factors, the extraction rate of the palmitic acid is taken as a response value, and a quadratic regression equation aiming at the characteristic of a starch matrix of yellow wine small Qu Gao is established through three-factor three-level experimental design: ; Wherein Y is the extraction rate of palmitic acid, A is the extraction time, B is the extraction temperature, C is the feed-liquid ratio, Is a constant term which is used to determine the degree of freedom, ~ The method is characterized in that the method is used for obtaining regression coefficients, the significance of a regression equation is verified through variance analysis, P is less than 0.01, the fitting degree, R2 is more than or equal to 0.95, insignificant factors are removed, P is more than 0.05, and the optimal extraction process condition is optimized and determined.
  8. 8. The multi-dimensional analysis and evaluation method of distiller' S yeast quality according to claim 1, wherein step S5 specifically comprises the steps of: S501, adopting an HP-5 MS elastic quartz capillary column with the specification of 30m multiplied by 0.25 mm and the specification of 0.25 mu m, setting the temperature of a sample inlet to 250 ℃, adopting a programmed heating process, namely, setting the initial column temperature to 60 ℃, keeping 1 min, then heating to 220 ℃ at the heating rate of 20 ℃ per minute, keeping 1 min, heating to 300 ℃ at the heating rate of 5 ℃ per minute, keeping 7 min, adopting high-purity helium as carrier gas, setting the purity to be more than or equal to 99.999%, setting the flow rate of the carrier gas to 1 mL per minute, and adopting an undivided sample injection mode, wherein the sample injection volume is 1 mu L; S502, setting the temperature of a chromatographic-mass spectrometry interface to 280 ℃, setting the ionization energy to 70 eV by adopting an electron bombardment source, setting the temperature of an ion source to 230 ℃, adopting a full-scan mode for qualitative analysis, wherein the scanning range covers characteristic ions of a target flavor compound, adopting a selective ion monitoring mode for quantitative analysis, specifically monitoring characteristic ions of palmitic acid and an internal standard, and setting the solvent delay time to 7 min so as to avoid interference of a solvent peak to the target peak; and S503, quantitatively analyzing by adopting an internal standard method, taking the peak area of an internal standard methyl nineteen-ate as a reference, calculating a correction factor f by using the peak area ratio of palmitic acid to the internal standard, wherein the calculation formula of the correction factor is f= (C_s multiplied by A_i)/(C_i multiplied by A_s), C_s is the concentration of a palmitic acid reference substance, A_i is the peak area of the internal standard, C_i is the concentration of the internal standard, A_s is the peak area of the palmitic acid, and calculating the specific content of the palmitic acid by combining the correction factor, namely C_sample= (A_sample multiplied by C_i multiplied by f)/A_i.
  9. 9. The method for multi-dimensional analysis and evaluation of distiller' S yeast quality according to claim 1, wherein in step S6, the method specifically comprises the steps of: S601, distributing weights, namely, a sensory index total score accounts for 30%, a liquefying force accounts for 25%, an acid ester ratio accounts for 20%, a2, 4-di-tert-butylphenol safety index accounts for 15%, moisture and color gradation accounts for 5%, and palmitic acid and ketone accounts for 5%; S602, grading rules, namely, grading all distiller's yeast samples to be evaluated, wherein the samples with the best grading are ranked inside each evaluation index, the samples with the worst grading are 1/4 of the weight corresponding to the index, and the samples in the middle of the grading are calculated to obtain scores according to a linear interpolation method, wherein 2, 4-di-tert-butylphenol is used as a safety index, if the content of the 2, 4-di-tert-butylphenol exceeds a preset safety threshold, all the weight of the index is deducted, and palmitic acid is used as an index component, and if the content of the palmitic acid exceeds a preset reasonable range, part or all the weight of the index is deducted according to an exceeding proportion; Step S603, defining the term, namely, the alkyd ester proportion, specifically refers to the sum of chromatographic peak areas of alcohols, esters and organic acid compounds in a distiller's yeast sample, and is used for quantifying the coordination of the distiller's yeast flavor relative to the percentage of the total peak area of all detectable flavor compounds in the distiller's yeast.
  10. 10. The method for multi-dimensional analysis and evaluation of distiller' S yeast quality according to claim 9, wherein in step S6, yellow wine small yeast is classified into three classes according to the composite score, Primary distiller's yeast: the comprehensive score is more than or equal to 85 points; the secondary distiller's yeast has a comprehensive score of less than or equal to 70 and less than or equal to 85; Three-stage distiller's yeast, wherein the comprehensive score is less than 70; if the content of the 2, 4-di-tert-butylphenol exceeds a safety threshold, the method directly judges that the distiller's yeast is unqualified and does not participate in grading.

Description

Multidimensional analysis and evaluation method for distiller's yeast quality Technical Field The invention relates to the technical fields of food analytical chemistry and food processing, in particular to a multidimensional analytical evaluation method for distiller's yeast quality. Background Yellow wine is one of three ancient wines in the world and contains a deep Chinese brewing culture, wherein a geographical mark product represented by the yellow wine in the county of China is brewed by adopting a small yeast fermentation process, the quality of the product is closely related to the quality of small yeast of the yellow wine, and the quality of the small yeast directly determines the final flavor, taste and quality grade of the yellow wine. The distiller's yeast is used as a core saccharification starter in the process of brewing the yellow wine, is rich in various microorganisms (such as mould, saccharomycetes and bacteria) and enzyme systems (such as liquefying enzyme and saccharifying enzyme), is a soul for brewing the yellow wine, and has quality advantages and disadvantages which directly influence the fermentation efficiency and the wine yield of the yellow wine and obviously influence the chemical composition, the flavor characteristics and the product stability of the yellow wine. However, the current yellow wine industry is faced with various problems of complicated distiller's yeast sources, uneven distiller's yeast quality of different production places and different batches, unstable distiller's yeast quality caused by lack of uniform standardized flow in the distiller's yeast production process and large fluctuation of production process parameters, and more importantly, the traditional distiller's yeast quality control mainly depends on the personal experience of a winemaker, and is evaluated by observing subjective indexes such as appearance, smell or growth condition of hyphae of the distiller's yeast, or the distiller's yeast quality is reversely estimated according to the measurement result of the yellow wine quality generated after fermentation, and the evaluation mode has extremely strong subjectivity, uncertainty and hysteresis, so that the uniformity and stability of the distiller's yeast quality of different batches and different production places are difficult to ensure, and the requirements of standardized and large-scale development of the yellow wine industry are also not met. In recent years, although some local standards are issued for standardizing the production technology of small yellow rice wine yeast, the manufacturing process of the yellow rice wine yeast involves various raw materials and a plurality of process links, and the factor variation (such as raw material proportion, fermentation temperature and fermentation time) of any link can obviously influence the chemical component content, enzyme activity level and flavor characteristics of the finished product of the yellow rice wine yeast, and the existing local standards still do not solve the core problems of quantitative evaluation of the quality of the yellow rice wine yeast. Meanwhile, the prior art has less researches on the aspects of accurate quantitative analysis, index component screening and extraction process optimization of distiller's yeast flavor substances, and fails to establish a multidimensional evaluation system covering sensory, physicochemical, biochemical and chemical compositions, and cannot comprehensively and objectively reflect the quality level of distiller's yeast. In the prior art, the evaluation of distiller's yeast quality is mostly focused on the Daqu of white spirit or the sensory of white spirit, for example, research is conducted on screening sensory descriptors through principal component analysis and drawing a flavor profile to evaluate the quality of white spirit, or the Daqu grade is divided by establishing a comprehensive evaluation model (F value) containing a plurality of physicochemical and biochemical indexes. However, none of the methods involves a specific object of yellow wine starter, and the characteristic components with indicating significance cannot be screened from the chemical fingerprint, and the safety early warning indexes are not systematically included in the evaluation system. Therefore, developing a multidimensional quantitative evaluation method specific to yellow wine small starter is important. Disclosure of Invention Aiming at the defects existing in the prior art, the invention aims to provide a multidimensional analysis and evaluation method for the quality of the distiller's yeast, which starts from four core dimensions of sensory attributes, physical and chemical properties, biochemical functions and chemical components, carries out comprehensive, objective and systematic quantitative evaluation on the quality of the distiller's yeast, fills the blank of the prior art, and provides technical support for standardized production and quality cont