LU602012B1

LU602012B1 - Spirulina-potato composite fermented yogurt

Info

Publication number: LU602012B1
Application number: LU602012A
Authority: LU
Inventors: Haiyan Liu; Yang Jiao; Xingyan Li; Xiaoxue He; Lijuan Wang; Guanghong Luo; Shenghui Yang; Nanbin Wang
Original assignee: Univ Hexi; Gansu Kaiyuan Biotechnology Development Center Llc
Priority date: 2025-06-11
Filing date: 2025-06-11
Publication date: 2025-12-11

Abstract

The present invention relates to the field of food processing technology. A Spirulina-potato composite fermented yogurt is provied. By incorporating fresh Spirulina paste into the fermented yogurt product, whey separation is completely prevented during 15-day storage at 4 °C, while significantly enhanced scavenging effects on both 2,2-diphenyl-1-picrylhydrazyl (DPPH) and 2,2'- Azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) radicals are achieved, thereby effectively mitigating whey separation in yogurt under low-temperature cold chain storage conditions.

Description

BL-5966

SPIRULINA-POTATO COMPOSITE FERMENTED YOGURT LU602012

TECHNICAL FIELD

The present invention relates to the technical field of food processing, and particularly to a

Spirulina-potato composite fermented yogurt.

BACKGROUND

Spirulina contains abundant physiologically active substances and nutritional components, demonstrating significant value in nutritional healthcare and preventive medical applications.

Multiple research studies have confirmed that Spirulina proteins/polypeptides constitute an excellent source of high-quality bioactive peptides.

With the advancement of science and the progress of society, fermented yogurt has gained widespread consumer preference due to distinctive flavor characteristics, rich nutritional content, and beneficial physiological functions. However, conventional preparation methods of fresh spirulina-fermented yogurt frequently exhibit technical defects during product transportation and commercialization, including excessive acidity, whey separation, stratified curd suspension, and gas formation in coagulated milk masses. Such technical defects lead to product reputation impairment in minor cases and cause substantial financial losses to enterprises in severe instances.

SUMMARY

An objective of the present invention is to provide a Spirulina-potato composite fermented yogurt.

To solve the foregoing objective of the invention, the present invention adopts the following technical solutions.

The present invention provides a Spirulina-potato composite fermented yogurt, and the

Spirulina-potato composite fermented yogurt comprises the following components in percentage by weight: 60%-80% fresh milk, 6%-20% fresh Spirulina paste, 0.05%-0.15% potato hydroxypropyl starch, 0.15%-0.45% starter culture, 2%-5% xylitol, 1%-2% sucrose, with the balance being softened water.

The present invention significantly mitigates acidification-induced flavor deterioration and whey syneresis occurring during product distribution and storage by incorporating potato hydroxypropyl starch into fermented milk containing fresh Spirulina paste.

Further, the Spirulina-potato composite fermented yogurt further comprises fresh potato mash in an amount of from 0.75% to 2% by weight.

The present invention alleviates post-acidification in fermented yogurt by incorporating fresh potato mash into the fermented yogurt. 1

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Further, the Spirulina-potato composite fermented yogurt comprises the followirg602012 components in percentage by weight: 74.12% fresh milk, 10.00% fresh Spirulina paste, 0.05% potato hydroxypropyl starch, 1.25% fresh potato mash, 0.32% starter culture, 2.47% xylitol, 1.15% sucrose, with the balance being softened water.

Further, a preparation method of the fresh Spirulina paste is as follows: mixing fresh

Spirulina liquid with softened water at a 1:1 volume ratio to obatin a mixture, followed by subjecting the mixture to pulsed ultrasonication comprising 10-second ultrasonication intervals alternating with 2-second pauses, with a total ultrasonication duration of 20 to 30 seconds, heating the mixture to 90 °C-95 °C and maintaining the temperature for 30 minutes, then cooling the mixture under airtight conditions to 40 °C, and obtaining the fresh Spirulina paste.

Further, a preparation method of the fresh Spirulina liquid is as follows: collecting Spirulina algal bodies and performing liquid suspension culture, removing impurities from the culture solution followed by washing with water, adjusting the algal biomass to 10% +5%, and obtaining the fresh Spirulina liquid.

The fresh Spirulina paste obtained through the processing method of the present invention not only substantially preserves the original nutritional components of fresh Spirulina, but also reduces unit operations required in the production process. Furthermore, the fermentation treatment effectively mitigates the characteristic fishy odor associated with Spirulina.

Further, a preparation method of the fresh potato mash is as follows: taking fresh potatoes, steaming over water for 30 minutes, removing peels while hot, continuously beating until a paste- like consistency is achieved, and obtaining fresh potato mash.

Wherein the potatoes are selected from starch-rich processing varieties suitable for potato flour production, such as Solanum tuberosum 'Atlantic' and Solanum tuberosum "Kexin'; and the present invention addresses the issue of post-acidification in yogurt by incorporating fresh potato mash into the yogurt.

Further, the fresh milk complies with the requirements specified in NY/T1172-2006 Quality

Management Standard for Raw Cow Milk.

Wherein the starter culture may be in the form of a direct vat set (DVS) powder or a slant- preserved culture.

The present invention further provides a preparation method of the Spirulina-potato composite fermented yogurt, including the following steps: 1) pretreatment of fresh Spirulina paste: mixing fresh Spirulina liquid with softened water at a 1:1 volume ratio to obatin a mixture, followed by subjecting the mixture to pulsed ultrasonication comprising 10-second ultrasonication intervals alternating with 2-second pauses, with a total 2

BL-5966 ultrasonication duration of 20 to 30 seconds, heating the ultrasonic extract to 90 °C-95 °C ahd602012 maintaining the temperature for 30 minutes, then cooling the mixture to 40 °C by cooling in a closed system, and obtaining the fresh Spirulina paste; 2) pretreatment of fresh potato mash: taking fresh potatoes, steaming over water for 30 minutes, removing peels while hot, continuously beating until achieving a paste-like consistency is achieved, and obtaining the fresh potato mash; 3) pretreatment of starter culture: mixing a direct vat set (DVS) lactic acid bacterial powder with a 5% sugar solution prepared in softened water at a mass ratio of 1:10, followed by incubating the mixture under shaking conditions at 40 °C for 30 minutes; or mixing a DVS bacterial powder with skimmed milk powder and water in a mass ratio of 1:12, then shake- culturing the mixture at 37°C-41 °C under 100 r/min for 8-12 hours, and obtaining the starter culture; 4) preheating and homogenizing: mixing a specified amount of fresh milk, fresh potato mash, xylitol, sucrose, and potato hydroxypropyl starch, adding a specified amount of softened water and uniformly mixing to obtain a mixed solution, preheating the mixed solution to 60°C+5 °C, either homogenizing by high-speed shear at 800-1000 r/min for 2-5 minutes, or pressure homogenizing at 150 bar and 300 bar, respectively followed by mixing, and obtaining a homogenized liquid; 5) sterilizing: heating the homogenized liquid to 90 °C-95 °C and maintaining the temperature for 20-30 minutes; 6) inoculating and pre-fermenting: cooling the sterilized homogenized liquid to 40 °C- °Cby cooling in a closed system, mixing uniformly with a specified amount of fresh

Spirulina paste, adding a specified amount of starter culture, fermenting at 38 °C-43 °C for 5-9 hours, and obtaining curd, 7) demulsifying: demulsifying the curd using a demulsification machine at 150-250 r/min for 30-60 seconds; and 8) post-fermentation: rapidly cooling the curd to 0 °C-4°C, followed by fermenting the cooled curd for 8-12 hours, and obtaining fresh Spirulina-potato composite fermented yogurt.

By adopting the aforementioned technical solution, the present invention has the following beneficial effects:

According to the present invention, fresh Spirulina is utilized in fermented yogurt products, which diversifies the edible forms of spirulina, and the obtained yogurt exhibits no whey syneresis under 4 °C storage for 15 days and demonstrates significant scavenging effects on 2,2-Diphenyl- 1-picrylhydrazyl (DPPH) and 2,2'-Azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) free 3

BL-5966 radicals, thereby addressing the issue of whey syneresis in low-temperature cold-chain yogurt/602012 products.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates a bar chart showing pH changes of the fermented yogurt across experimental groups;

FIG. 2 illustrates a bar chart showing acidity changes of the fermented yogurt across experimental groups;

FIG. 3 illustrates a bar chart depicting the moisture release variations of the fermented yogurt across experimental groups;

FIG. 4 illustrates a bar chart showing the DPPH radical scavenging efficiency of the fermented yogurt across experimental group; and

FIG. 5 illustrates a bar chart presenting the ABTS radical scavenging efficiency of the fermented yogurt across experimental groups.

DETAILED DESCRIPTION OF THE EMBODIMENTS

The direct-vat-set (DVS) starter cultures described in the present invention are purchased from Yikeshangyuan Co., Ltd. under the brand Danix. The DVS lactic acid bacteria powder is mixed with a mixture of skim milk powder and water (or emulsified aqueous sugar solution) in a mass ratio of 1:100.

Example 1

A Spirulina-potato composite fermented yogurt, comprising the following components by weight: 720 g of fresh milk, 85 g of fresh Spirulina paste, 1 g of potato hydroxypropyl starch, 3 g of starter culture, 139 g of softened water, 25 g of xylitol, 12 g of sucrose, and 15 g of fresh potato mash.

The Spirulina-potato composite fermented yogurt was prepared by the following method, as described below: 1) pretreatment of fresh Spirulina paste: Spirulina biomass was subjected to liquid suspension culture; the culture medium was clarified and rinsed; the biomass content was adjusted to 10% by weight; and a fresh Spirulina liquid was obtained; the fresh Spirulina liquid and softened water were mixed at a volume ratio of 1:1 to form a mixture, then the mixture was subjected to ultrasonic treatment in an intermittent mode comprising 10-second intervals of sonication followed by 2- second intervals of pause, with the total ultrasonic duration being controlled to 20 seconds, thereby preparing an ultrasonically treated extract. The ultrasonically treated extract was heated to 90 °C and maintained at the temperature for 30 minutes. Subsequently, the heated extract was cooled to 40 °C by cooling in a closed system, whereby the fresh Spirulina paste was obtained; 4

BL-5966 2) pretreatment of fresh potato mash: fresh potatoes were selected and steamed over boilirkg/602012 water for 30 minutes, then the steamed potatoes were peeled while still hot and continuously beaten until a paste-like consistency was achieved, whereby the fresh potato mash was obtained; 3) pretreatment of starter culture: the direct vat set lactic acid bacteria powder and 5% softened water sugar solution were mixed at a mass ratio of 1:10, followed by incubation under thermostatic shaking conditions at 40 °C for 30 minutes, whereby the starter culture was obtained; 4) preheating and homogenizing: the fresh milk, fresh potato mash, xylitol, sucrose, softened water, and potato hydroxypropyl starch were uniformly mixed to obtain a mixture, the mixture was preheated 60 °C, followed by homogenization through high-speed shear at 800 r/min for 5 minutes; 5) sterilizing: the homogenized liquid was heated to 90 °C and the temperature was maintained for 30 minutes; 6) inoculating and pre-fermenting: the sterilized homogenized liquid was cooled to 40 °C by cooling in a closed system, and then uniformly mixed with fresh Spirulina paste, a specified amount of the starter culture was added, followed by fermentation at 40 °C for 5 hours, whereby curd was obtained; 7) demulsifying: the curd was subjected to demulsification treatment in a demulsifier at 100 r/min for 30 seconds; and 8) post-fermentation: the curd was rapidly cooled to 4 °C, and then fermented for 8 hours, whereby the Spirulina-potato composite fermented yogurt was obtained.

Example 2

The present example provided a Spirulina-potato composite fermented yogurt, and the

Spirulina-potato composite fermented yogurt comprised the following components by weight: 7412 g of fresh milk, 1000 g of fresh Spirulina paste, 5 g of potato hydroxypropyl starch, 125 g of fresh potato mash, 32 g of starter culture, 1064 g of softened water, 247 g of xylitol, and 115 g of sucrose. The Spirulina-potato composite fermented yogurt was prepared by the following method, as described below: 1) pretreatment of fresh Spirulina paste: Spirulina biomass was subjected to liquid suspension culture, the culture medium was clarified and rinsed, the biomass content was adjusted to 10% by weight, and a fresh Spirulina liquid was obtained; the fresh Spirulina liquid and softened water were mixed at a volume ratio of 1:1 to form a mixture, then the mixture was subjected to ultrasonic treatment in an intermittent mode comprising 10-second intervals of sonication followed by 2- second intervals of pause, with the total ultrasonic duration being controlled to 40 seconds, thereby preparing an ultrasonically treated extract. The ultrasonically treated extract was heated to 90 °C

BL-5966 and maintained at the temperature for 30 minutes. Subsequently, the heated extract was cooled t&/692012 °C by cooling in a closed system, whereby fresh spirulina paste was obtained, 2) pretreatment of fresh potato mash: fresh potatoes were selected and steamed over boiling water for 30 minutes, and then the steamed potatoes were peeled while still hot and continuously beaten until a paste-like consistency was achieved, whereby the fresh potato mash was obtained; 3) pretreatment of starter culture: the direct vat set lactic acid bacteria powder and 5% softened water sugar solution were mixed at a mass ratio of 1:10, followed by incubation under thermostatic shaking conditions at 40 °C for 30 minutes, whereby the starter culture was obtained; 4) preheating and homogenizing: fresh milk, fresh potato mash, xylitol, sucrose, and potato hydroxypropyl starch were mixed, and softened water was added to obtain a homogeneous mixture, then the mixture was preheated to 60 °C and homogenized at a pressure of 300 bar for 5 minutes; 5) sterilizing: the homogenized liquid was heated to 95 °C and the temperature was maintained for 30 minutes; 6) inoculating and pre-fermenting: the sterilized homogenate was cooled to 45 °C by cooling in a closed system, and then uniformly mixed with fresh Spirulina paste, a specified amount of the starter culture was added, followed by fermentation at 45 °C for 6 hours, whereby curd was obtained; 7) demulsifying: the curd was subjected to demulsification treatment in a demulsifier at 100 r/min for 30 seconds; and 8) post-fermentation: the curd was rapidly cooled to 4 °C, and fermented for 8 hours, whereby the Spirulina-potato composite fermented yogurt was obtained.

Comparative Example 1

Plain fermented yogurt, the fermented yogurt comprises the following components by weight: 700 g of fresh milk, 4.9 g of corn starch, 3 g of starter culture, 210 g of softened water, 25 g of xylitol, and 12 g of sucrose.

A preparation method of the plain fermented yogurt was as follows: 1) pretreatment of starter culture: the direct vat set (DVS) lactic acid bacteria powder was mixed with a 5% softened water-based sugar solution, and the resulting mixture was incubated under thermostatic shaking conditions at 40 °C for 30 minutes; 2) preheating and homogenizing: fresh milk, corn starch, xylitol, and sucrose were mixed with 190 g of softened water to obtain a mixture, then the mixture was preheated to 60°C and homogenized at a high-speed shear rate of 800 r/min for 5 minutes; 3) sterilizing: the homogenized liquid was heated to 95 °C and the temperature was maintained for 30 minutes; 6

BL-5966 4) inoculating and pre-fermenting: the sterilized homogenate was cooled to 40 °C by coolirt$/602012 in a closed system, a specified amount of the starter culture was added, followed by fermentation at 40 °C for 5 hours, whereby curd was obtained; 5) demulsifying: the curd was subjected to demulsification treatment in a demulsifier at 150 r/min for 30 seconds; and 6) post-fermentation: the curd was rapidly cooled to 4 °C, and fermented for 8 hours, whereby the plain fermented yogurt was obtained.

Experimental Example 1

The fresh Spirulina-potato composite fermented yogurts of Examples 1-2 of the present invention and the plain fermented yogurt provided in Comparative Example 1 were subjected to a 15-day evaluation of yogurt quality indicators and DPPH/ABTS radical scavenging activity tests, where the yogurt quality indicators included pH measurement, acidity determination, and syneresis measurement. Wherein, the water content was determined by a centrifugation method, which was specifically operated as follows: a sample of 10 g was weighed and placed in a centrifuge tube, and the sample was centrifuged at 6000 r/min for 10 minutes under a temperature of 4 °C; after centrifugation, the supernatant was decanted and the remaining sample was weighed, the water release rate (%) was calculated by the formula: [(W2 - W1)/W2] x 100%, wherein W1 represented a weight of the centrifuge tube before centrifugation, and W2 represented a weight after centrifugation and removal of the supernatant; the acidity was determined according to the

National Food Safety Standard GB5413.34-2010 (Method for Determination of Acidity in Milk and Dairy Products); for the DPPH and ABTS radical scavenging rate assays, the samples were extracted with a yogurt-to-buffer solution at a volumetric ratio of 1:5, followed by centrifugation to obtain the supernatant for measurement; and the pH value was measured using a pH meter method.

As demonstrated in FIG. 1 ('Algae-Potato Yogurt 1' is the Spirulina-potato composite fermented yogurt provided by Example 1; 'Algae-Potato Yogurt 2' is the Spirulina-potato composite fermented yogurt provided by Example 2; and 'Plain Yogurt' is the plain fermented yogurt provided by Comparative Example 1). The pH values of the Example 1 and 2 groups are measured to be above 4.2, exceeding the values recorded for the Comparative Example 1. As shown in FIG. 2, the acidity of the algae-potato yogurt on day 15 in the Example 1-2 groups is measured to range between 80-100 °T, which is lower than the acidity of the Comparative Example 1. Thus, it is demonstrated that the problem of excessively sour taste encountered during transportation and sales of conventional fermented yogurt is effectively resolved by the product disclosed in the present invention. 7

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As demonstrated by FIG. 3, the syneresis rates of Examples 1-2 are maintained at 26-32%#602012 with no significant variation observed within 15 days. In contrast, the syneresis rate of

Comparative Example 1 reaches approximately 45% within 15 days, demonstrating that Examples 1-2 demonstrate superior moisture retention capability and whey separation prevention effect compared to Comparative Example 1.

As demonstrated in FIG. 4 and FIG. 5, Examples 1-2 exhibit significantly higher scavenging rates against both DPPH and ABTS radicals compared to Comparative Example 1. These results demonstrate that the product of the present invention possesses comprehensive nutritional value, remarkable antioxidant effects, and lower production costs, thereby enhancing the market competitiveness of the fermented yogurt. 8

Claims

BL-5966 CLAIMS LU602012

1. A Spirulina-potato composite fermented yogurt, comprising the following components in percentage by weight: 60%-80% fresh milk, 6%-20% fresh Spirulina paste, 0.05%-0.15% potato hydroxypropyl starch, 0.15%-0.45% starter culture, 2%-5% xylitol, 1%-2% sucrose, with the balance being softened water.

2. The Spirulina-potato composite fermented yogurt according to claim 1, wherein the Spirulina-potato composite fermented yogurt further comprises fresh potato mash in an amount of from 0.75% to 2% by weight.

3. The Spirulina-potato composite fermented yogurt according to claim 2, wherein the Spirulina-potato composite fermented yogurt comprises the following components in percentage by weight: 74.12% fresh milk, 10.00% fresh Spirulina paste, 0.05% potato hydroxypropyl starch,

1.25% fresh potato mash, 0.32% starter culture, 2.47% xylitol, 1.15% sucrose, with the balance being softened water.

4. The Spirulina-potato composite fermented yogurt according to claim 1, wherein a preparation method of the fresh Spirulina paste is as follows: mixing fresh Spirulina liquid with softened water at a 1:1 volume ratio to obatin a mixture, followed by subjecting the mixture to pulsed ultrasonication comprising 10-second ultrasonication intervals alternating with 2-second pauses, with a total ultrasonication duration of 20 to 30 seconds, heating the mixture to 90 °C-95 °C and maintaining the temperature for 30 minutes, then cooling the mixture under airtight conditions to 40 °C, and obtaining the fresh Spirulina paste.

5. The Spirulina-potato composite fermented yogurt according to claim 4, wherein a preparation method of the fresh Spirulina liquid is as follows: collecting Spirulina algal bodies and performing liquid suspension culture thereof, removing impurities from the culture solution followed by washing with water, adjusting the algal biomass to 10% +5%, and obtaining the fresh Spirulina liquid.

6. The Spirulina-potato composite fermented yogurt according to claim 2, wherein a preparation method of the fresh potato mash is as follows: taking fresh potatoes, steaming over water for 30 minutes, removing peels while hot, continuously beating until a paste-like consistency is achieved, and obtaining the fresh potato mash.

7. The Spirulina-potato composite fermented yogurt according to claim 1, wherein the fresh milk complies with the requirements specified in NY/T1172-2006 Quality Management Standard for Raw Cow Milk.

8. A preparation method of the Spirulina-potato composite fermented yogurt according to any one of claims 1-7, comprising the following steps: 9

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1) pretreatment of fresh Spirulina paste: mixing fresh Spirulina liquid with softened water a/602012 a 1:1 volume ratio to obatin a mixture, followed by subjecting the mixture to pulsed ultrasonication comprising 10-second ultrasonication intervals alternating with 2-second pauses, with a total ultrasonication duration of 20 to 30 seconds, heating the ultrasonic extract to 90 °C-95 °C and maintaining the temperature for 30 minutes, then cooling the mixture to 40 °C by cooling in a closed system, and obtaining the fresh Spirulina paste;

2) pretreatment of fresh potato mash: taking fresh potatoes, steaming over water for 30 minutes, removing peels while hot, continuously beating until a paste-like consistency is achieved, and obtaining the fresh potato mash;

3) pretreatment of starter culture: mixing a direct vat set (DVS) lactic acid bacterial powder with a 5% sugar solution prepared in softened water at a mass ratio of 1:10, followed by incubating the mixture under shaking conditions at 40 °C for 30 minutes; or mixing a DVS bacterial powder with skimmed milk powder and water in a mass ratio of 1:12, then shake- culturing the mixture at 37°C-41 °C under 100 r/min for 8-12 hours, and obtaining the starter culture;

4) preheating and homogenizing: mixing a specified amount of fresh milk, fresh potato mash, xylitol, sucrose, and potato hydroxypropyl starch, adding a specified amount of softened water and uniformly mixing to obtain a mixed solution, preheating the mixed solution to 60°C+5 °C, either homogenizing by high-speed shear at 800-1000 r/min for 2-5 minutes, or pressure homogenizing at 150 bar and 300 bar, respectively followed by mixing, and obtaining a homogenized liquid;

5) sterilizing: heating the homogenized liquid to 90-95 °C and maintaining the temperature for 20-30 minutes;

6) inoculating and pre-fermenting: cooling the sterilized homogenized liquid to 40°C-45°C by cooling in a closed system, mixing uniformly with a specified amount of fresh Spirulina paste, adding a specified amount of starter culture, fermenting at 38°C-43°C for 5-9 hours, and obtaining curd;

7) demulsifying: demulsifying the curd using a demulsification machine at 150-250 r/min for 30-60 seconds; and

8) post-fermentation: rapidly cooling the curd to 0°C-4°C, followed by fermenting the cooled curd for 8-12 hours, and obtaining the fresh Spirulina-potato composite fermented yogurt.