Pediococcus pentosaceus for improving quality of cider and application thereof

Abstract

The invention provides pediococcus pentosaceus capable of improving the quality of cider and application of the pediococcus pentosaceus, and relates to the technical field of microorganisms and food processing, the pediococcus pentosaceus capable of improving the quality of cider is pediococcus pentosaceus SCFF125, and is preserved in Guangdong Microbial Culture Collection Center, and the preservation number is GDMCC No: 67168. Experimental data show that the efficiency of converting the L-malic acid in the apple juice into the L-lactic acid by the pediococcus pentosaceus SCFF125 is higher, the acidity balance of the cider is improved, the acerbity of the cider is effectively reduced, and the roundness of the taste and the product stability of the cider are improved. Besides, the pediococcus pentosaceus SCFF125 effectively improves the oxidation resistance of the cider, further, the strain optimizes the flavor characteristics of the cider through metabolic activity, the content of esters and higher alcohols is increased, the total amount of volatile substances is increased by 53% compared with that of a control group, and the cider is endowed with richer and more harmonious fruity flavor and mellowness.

Description

Technical Field

[0001] This invention relates to the fields of microbiology and food processing technology, and in particular to a Pediococcus pentosaccharis species for improving the quality of cider and its application. Background Technology

[0002] As a traditional fermented beverage, the metabolic activity of microorganisms during fermentation is crucial to the quality of cider. For a long time, brewer's yeast (Saccharomyces cerevisiae) has been a key factor in this process. Saccharomyces cerevisiae Yeast (or malic acid) is the core microbial strain in cider fermentation, responsible for converting sugars into ethanol and producing basic flavor compounds. However, single-strain fermentation has significant limitations: cider has a high content of organic acids (especially malic acid), resulting in a sharp sour taste and an unbalanced flavor profile; at the same time, its antioxidant capacity is weak, and it produces fewer types of flavor compounds, making it difficult to meet the demands of modern consumers for high-quality cider.

[0003] Lactic acid bacteria have attracted attention due to their unique metabolic characteristics, and the malic-lactic fermentation (MLF) they stimulate is considered a key pathway to reduce acidity and enhance flavor complexity in fruit wines. During MLF, lactic acid bacteria convert dicarboxylic acid (malic acid) into monocarboxylic acid (lactic acid), significantly improving the wine's body and mouthfeel. Currently, the main lactic acid bacteria used for fruit wine fermentation include *Lactobacillus* (*Lactobacillus* spp.). Lactobacillus ), genus *Sacchariformis* Oenococcus ), Pediococcus ( Pediococcus ) and Leuconostoc genus ( Leuconostoc Studies have shown that different strains exhibit significant differences in metabolic characteristics; for example, *Lactobacillus paracasei* (…). Lactobacillus paracasei ) and fermenting lactobacillus ( Limosilactobacillus fermentum Although it can adapt to the fermentation environment, its effects on flavor building and antioxidant enhancement are limited.

[0004] Cider fermentation is characterized by high acidity, high osmotic pressure, and ethanol stress. Under these conditions, the activity of many lactic acid bacteria is limited, leading to slow or incomplete MLF initiation. Specifically, the metabolic activity of some Lactobacillus strains decreases significantly below pH 3.5, making it difficult to effectively complete acidity conversion. Although some lactic acid bacteria have provided direction for improving cider quality through MLF, some problems remain. For example, the lactic acid bacteria strains used often only focus on improving one aspect, such as Lactobacillus brevis. Lactobacillus brevis While it can effectively degrade malic acid, it contributes little to flavor compounds; whereas other strains, such as *Lactobacillus plantarum*... Lactiplantibacillus plantarum While it can enhance antioxidant properties, it may also affect the balance of flavor due to excessive acid production. Therefore, this invention proposes a Pediococcus pentosaccharis species for improving cider quality and its application to solve the problems existing in the prior art. Summary of the Invention

[0005] To address the aforementioned problems, the present invention aims to propose a Pediococcus pentosaccharis strain for improving the quality of cider and its application. The present invention has the advantages of being highly targeted, comprehensive in function, and highly adaptable, and can solve the problems existing in the prior art.

[0006] To achieve the objective of this invention, the invention is implemented through the following technical solution: a Pediococcus pentosaccharis strain for improving the quality of cider, wherein the strain number of Pediococcus pentosaccharis is SCFF125, and it is deposited at the Guangdong Provincial Center for Microbial Culture Collection with accession number GDMCC No: 67168.

[0007] Application of Pediococcus pentosaceus in cider fermentation.

[0008] Further improvements are made in that: the Pediococcus pentosaceus SCFF125 improves the acidity balance, enhances antioxidant properties, and optimizes flavor characteristics of cider during the fermentation process.

[0009] A further improvement is that the Pediococcus pentosaceus SCFF125 is mixed with the brewer's yeast of cider during fermentation, wherein the inoculation ratio of Pediococcus pentosaceus SCFF125 to brewer's yeast is 1:1.

[0010] Further improvements are made by using Pediococcus pentosaceus SCFF125 to convert L-malic acid into L-lactic acid through malolactic fermentation, thereby stabilizing the pH of the cider in the range of 4.0 to 4.5.

[0011] Further improvements are made in the following aspects: the improvement of antioxidant performance refers to promoting the synthesis of polyphenols by Pediococcus pentosaceus SCFF125, so that the total phenol content of cider reaches 400-500 mg / L, the hydroxyl radical scavenging rate is not less than 80%, and the total antioxidant capacity is not less than 150 mmol / L.

[0012] A further improvement is that the optimized flavor characteristics refer to increasing the content of esters and higher alcohols by Pediococcus pentosaceus SCFF125, wherein the esters include ethyl octanoate, ethyl hexanoate, and ethyl phenylacetate, and the higher alcohols include phenylethanol and isoamyl alcohol, etc.

[0013] The beneficial effects of this invention are as follows: (1) The *Pediococcus pentosaceus* SCFF125 provided by this invention can efficiently catalyze malolactic fermentation, converting L-malic acid into L-lactic acid and improving the acidity balance of cider. Experimental data show that the L-malic acid content in the *Pediococcus pentosaceus* SCFF125 treatment group decreased to 3.89 g / L, while the L-lactic acid content increased to 6.45 g / L. This process stabilized the pH value of the *Pediococcus pentosaceus* SCFF125 treatment group within the range of 4.0-4.5, effectively reducing the astringency of cider, improving the roundness of the cider's taste and product stability, and serving as a potential malolactic fermentation agent.

[0014] (2) This invention significantly enhances the antioxidant capacity of cider through metabolic activity. Experimental results show that the total phenol content of the Pediococcus pentosaceus SCFF125 treatment group reached 477.06 mg / L, the hydroxyl radical scavenging rate was not less than 84.50%, and the total antioxidant capacity was not less than 158.47 mmol / L, which provides a basis for enhancing the body's antioxidant capacity.

[0015] (3) This invention enriches the volatile compounds in cider, especially esters and alcohols, thereby not only achieving multi-dimensional improvement in cider quality, but also providing a reliable microbial solution for industrial production. Its benefits are reflected in improved taste, enhanced functionality and strengthened market competitiveness. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of the bacterial cell morphology provided by the present invention. Detailed Implementation

[0017] To enhance understanding of the present invention, the present invention will be further described in detail below with reference to embodiments. These embodiments are only used to explain the present invention and do not constitute a limitation on the scope of protection of the present invention.

[0018] according to Figure 1 As shown, this embodiment provides a Pediococcus pentosaceus strain for improving the quality of cider. The strain number of Pediococcus pentosaceus is SCFF125, which was deposited at the Guangdong Provincial Center for Microbial Culture Collection on January 27, 2025, with the accession number GDMCC No: 67168.

[0019] In this embodiment, the core technology involves using *Pediococcus pentosaceus* SCFF125 to ferment cider. Specifically, a mixed fermentation strategy is employed in the cider fermentation application: *Pediococcus pentosaceus* SCFF125 and *Saccharomyces cerevisiae* (strain SCFFFF228) are co-inoculated at a ratio of 1:1 (*Pediococcus pentosaceus*: *Saccharomyces cerevisiae*). The fermentation process is carried out at a constant temperature of 20°C for 12 days.

[0020] Therefore, this embodiment aims to comprehensively evaluate the improvement effect of this strain in the following three aspects: (1) Improve acidity balance: By catalyzing malic-lactic acid fermentation, L-malic acid is converted into L-lactic acid, so that the pH value of the product is stabilized in the ideal range of 4.0 to 4.5. This strain is a potential malic-lactic acid fermentation agent; (2) Improve antioxidant properties: promote the synthesis of polyphenols, aiming to make the total phenol content of cider reach 400-500 mg / L, and significantly improve its free radical scavenging ability and total antioxidant capacity. In this embodiment, the total phenol content of cider reaches 477.06 mg / L, the hydroxyl radical scavenging rate is not less than 84.50%, and the total antioxidant capacity is not less than 158.47 mmol / L; (3) Optimize flavor characteristics: Increase the content of esters (such as ethyl octanoate, ethyl hexanoate, ethyl phenylacetate) and higher alcohols (such as phenylethanol, isoamyl alcohol) to enrich the aroma.

[0021] Regarding the three functions mentioned above, we conducted corresponding experiments, as follows: We selected Fuji apples from Yanyuan as raw materials. After sorting and washing, the apples were juiced. The apple juice was then pretreated by adding 0.8% ascorbic acid as a color protectant and 100 mg / L potassium metabisulfite as a stabilizer, followed by enzymatic pretreatment using 0.02% pectinase and 0.05% cellulase at 50°C for 1 hour to optimize the fermentation substrate.

[0022] To ensure scientific comparison, this embodiment includes five experimental groups: *Lactobacillus paracasei* SCFF101, *Lactobacillus brevis* SCFF90, and *Lactobacillus fermentum* SCFF168 are used as controls for other lactic acid bacteria, and *Saccharomyces cerevisiae* SCFFF228 is used as a single-strain fermentation control group, ensuring comprehensiveness of the comparison. The five experimental groups are as follows: The experimental group PP125 was inoculated with Pediococcus pentosaceus SCFF125 and Saccharomyces cerevisiae SSCFFF228 in a ratio of 1:1 (i.e., lactic acid bacteria: yeast). The control group, LP101, was inoculated with Lactobacillus paracasei SCFF101 and Saccharomyces cerevisiae SCFFF228 in a 1:1 ratio. The control group LE90 was inoculated with Lactobacillus brevis SCFF90 and Saccharomyces cerevisiae SSCFFF228 in a 1:1 ratio. The control group LF168 was inoculated with Lactobacillus fermentum SCFF168 and Saccharomyces cerevisiae SCFFF228 in a 1:1 ratio. The control group SC228 was inoculated with only Saccharomyces cerevisiae SCFFF228 (without any added lactic acid bacteria) and served as the baseline control group for single-strain fermentation.

[0023] The inoculation concentration for all five groups was no less than 10. ^ The concentration was 7 CFU / mL, and fermentation was carried out at 20℃ for 12 days. After fermentation, the physicochemical properties and sensory quality of each group were measured, and the results are as follows: To assess the effectiveness of acidity balance improvement, the measured indicators were L-malic acid content, L-lactic acid content, and pH value. The comparison results are shown in Table 1. Table 1

[0024] As shown in Table 1, the most prominent advantage of the PP125 group lies in its highly efficient malolactic fermentation (MLF) capacity. Its L-malic acid residue was significantly lower than all control groups, while its L-lactic acid production was the highest, indicating that the *Pediococcus pentosaceus* SCFF125 strain's pathway for converting malic acid to lactic acid is highly efficient. This efficient conversion directly resulted in the ideal pH value (4.41), at the upper limit of the target range (4.0-4.5), meaning the acidity of the wine becomes more mellow and harmonious, rather than simply reduced. Compared to the LP101 and LE90 groups, the PP125 group achieved a higher degree of MLF completion, especially compared to the LF168 group and the SC228 group using only yeast, thus highlighting the superior survival and metabolic activity of *Pediococcus pentosaceus* SCFF125 under the cider fermentation environment (acidity, alcohol stress). In contrast, the LE90 group (*Lactobacillus brevis*) had a lower pH value (4.03), which may have produced other acidic substances, potentially hindering the balance of flavors. Therefore, Pediococcus pentosaceus SCFF125 is a potentially good malolactic starter. To improve antioxidant performance, the indicators used were total phenol content (mg / L), hydroxyl radical scavenging rate (%), and total antioxidant capacity (mmol / L). The comparison results are shown in Table 2. Table 2

[0025] As shown in Table 2, total phenolic content was positively correlated with antioxidant capacity (hydroxyl radical scavenging rate and total antioxidant capacity). The PP125 group had the highest total phenolic content (477.06 mg / L), which was 30% higher than the single-strain fermentation group of Saccharomyces cerevisiae (SC228 group). Phenolic compounds are important natural antioxidants in cider; their increased content not only enhances the ability to scavenge free radicals and delays the oxidation and deterioration of the cider, but also potentially improves the health value of the product. Furthermore, the antioxidant performance of the PP125 group was comprehensively superior to that of other lactic acid bacteria control groups, especially compared to the LP101 group, with a total phenolic content more than 100 mg / L higher. This indicates that Pediococcus pentosaceus SCFF125 can better promote the synthesis or transformation of phenolic compounds and release more bound phenols, which is one of its core advantages that distinguishes it from other strains.

[0026] For optimizing flavor characteristics, the determination indicators were total volatile matter (μg / L), ester content (μg / L), and key flavor compounds (ethyl octanoate and isoamyl alcohol). The comparison results are shown in Table 3. Table 3

[0027] As shown in Table 3, compared to the control group SC228, the total amount of volatile flavor compounds in the PP125 group increased by 53%, indicating that the addition of Pediococcus pentosaceus SCFF125 greatly enriched the aroma framework of cider. This richness mainly comes from the significant increase in flavor compounds such as esters and higher alcohols. The total ester content in the PP125 group (3122.68 μg / L) was significantly higher than other groups, especially ethyl caprylate. Ethyl caprylate has a pleasant fruity sweetness and aromas of pineapple and apple, and is a key component of the typical fruity aroma of cider. At the same time, the content of higher alcohols such as isoamyl alcohol (which has an alcoholic aroma and a slightly sweet taste) was also the highest. These, along with the esters, worked synergistically to construct a rich, complex, and harmonious aroma profile, providing a solid material basis for the excellent performance in subsequent sensory evaluations.

[0028] For sensory evaluation, the evaluation indicators are aroma, acidity, and overall acceptability, with a maximum score of ten. The comparison results are shown in Table 4: Table 4

[0029] As shown in Table 4, the sensory evaluation results are highly consistent with the aforementioned physicochemical indicators. The PP125 group achieved the highest scores in aroma (8.9 points), acidity balance (8.7 points), and overall acceptability (9.1 points), directly confirming its absolute advantage in flavor compound generation and acidity regulation. In particular, its overall acceptability far exceeded other groups, demonstrating that its comprehensive quality was clearly favored by the tasters. This clearly indicates that a rich aroma (high ester and alcohol content) and a smooth, harmonious acidity (suitable pH value) are the two pillars of a high sensory evaluation. The SC228 group (yeast only) lagged behind in all indicators, demonstrating the limitations of single-yeast fermentation. While other lactic acid bacteria control groups showed improvement in some aspects, the effects were uneven, failing to achieve the comprehensive and significant improvement in taste and flavor seen in the PP125 group.

[0030] Therefore, the above experimental data fully demonstrates that *Pediococcus pentosaceus* SCFF125, in co-fermentation with *Saccharomyces cerevisiae*, can efficiently improve the acidity balance of cider, significantly enhance antioxidant properties, and greatly enrich flavor compounds, ultimately yielding a cider product with excellent sensory quality. This invention provides a practical and effective solution to the problems in traditional cider fermentation.

[0031] The basic principles, main features, and advantages of this invention have been described above. Those skilled in the art should understand that this invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of the invention. Various changes and modifications can be made to this invention without departing from its framework and scope, and all such changes and modifications fall within the scope of the invention as claimed. The scope of protection of this invention is defined by the appended claims and their equivalents.

Claims

1. A Pediococcus pentosaceus for improving the quality of cider, characterized by: The strain number of the Pediococcus pentosaceus is SCFF125, which is preserved in Guangdong Microbial Culture Collection Center with the preservation number of GDMCC No: 67168.

2. The Pediococcus pentosaceus according to claim 1 is used in the fermentation of cider.

3. Use of P. pentosaceus according to claim 2 in the fermentation of cider, characterized in that: The Pediococcus pentosaceus SCFF125 improves the acidity balance, enhances the antioxidant performance and optimizes the flavor characteristics of cider during the fermentation process.

4. Use of P. pentosaceus according to claim 2 in the fermentation of cider, characterized in that: The Pediococcus pentosaceus SCFF125 is mixed with Saccharomyces cerevisiae for fermentation, wherein the inoculation ratio of the Pediococcus pentosaceus SCFF125 and Saccharomyces cerevisiae is 1:

1.

5. Use of P. pentosaceus according to claim 3 in the fermentation of cider, characterized in that: The improvement of the acidity balance of cider refers to the catalysis of the Pediococcus pentosaceus SCFF125 on the malolactic fermentation, which converts L-malic acid into L-lactic acid, so that the pH value of cider is stabilized in the range of 4.0-4.

5.

6. Use of a P. pentosaceus according to claim 3 in the fermentation of cider, characterised in that: The enhancement of the antioxidant performance refers to the promotion of the synthesis of polyphenols by the Pediococcus pentosaceus SCFF125, so that the total phenol content of cider reaches 400-500 mg / L, the hydroxyl radical clearance rate is not less than 80%, and the total antioxidant capacity is not less than 150 mmol / L.

7. Use of P. pentosus according to claim 3 in the fermentation of cider, characterised in that: The optimization of the flavor characteristics refers to the increase of the content of ester substances and high alcohols by the Pediococcus pentosaceus SCFF125, wherein the ester substances include ethyl octanoate, ethyl hexanoate and ethyl phenylacetate, and the high alcohols include isoamyl alcohol and phenethyl alcohol.

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