Soy Yogurt Research Articles

Formulations and evaluations of structural and physico-chemical properties of soy yogurts: Effect of incorporating soy protein isolate/chitosan complexed microgels

Novel complexed microgels with enhanced pH and ion stability were constructed using heat-denatured soy protein isolate (SPI) and Chitosan (CS). Their characteristics and their effects on the textural, rheological, and tribological properties of soy yogurt were investigated. The complexed microgels showed larger particle sizes, lower surface hydrophobicity, and higher turbidity than pure SPI microgels. Incorporating the SPI-CS complexed microgels into the yogurts increased their protein content from 3.94% to 5.07% and reduced their fat content from 2.17% to 1.99%. Additionally, incorporating the microgels enhanced the texture of the yogurts, including increased firmness, elasticity, and viscosity, alongside improved water holding capacity (WHC). The incorporation of 0.8% SPI-CS microgels led to the optimum physicochemical characteristics. Rheological analyses demonstrated that incorporating SPI-CS microgels led to an increase in apparent viscosity and shear modulus. Furthermore, the presence of the SPI-CS microgels significantly improved the lubrication properties. Microstructural analysis showed subtle differences in the gel structure of the yogurts after microgel addition. The three-dimensional network structure within the microgel-fortified yogurts was more compact than that in the control. Thus, SPI-CS microgels potentially improve the nutritional profile and quality attributes of plant-based yogurt products.

Fortification of local fruit parijoto on soy yogurt drink and economy analysis

Background: The food and beverage industry is a leading industry that is the government's focus in the Industrial Revolution 4.0. Culinary is the most popular economic sub-sector.. As a food product from biotechnology, yoghurt always manages to occupy a global market share. Yoghurt is proven to maintain the digestive system. Therefore innovation is needed, especially regarding materials, to boost product competitiveness. Animal milk substrate can be substituted with soy milk which is cheap but rich in protein. The addition of natural fortification is projected to improve product quality. Parijoto fruit (Medinilla speciosa) typical of the slopes of Mount Muria, Colo Village, Kab. Kudus was chosen as a fortificant because it is rich in antioxidants and antibacterial pathogens. At the same time, this adds to the usability and economic value of Parijoto, which is still low so far. Method: The research was conducted experimentally, referring to previous research methods. The formulation design was varied regarding adding Parijoto fruit extract to 100 ml of the product. Findings: From the results of the organoleptic test, the F1 formula (addition of 5 ml of Parijoto fruit extract) received the best acceptance from the panellists, with a preference level of 4.89. The product characteristics are liquid texture, alcoholic sweet taste, cream colour, and the aroma of Parijoto fruit tends to be faint. Conclusion:Parijoto Yogurt has advantages in terms of locality, price and nutrition. However, further research is needed based more collaboration to increase this product's health and economic impact local society. Novelty/Originality of this article: This study creates new functional food products and opens up opportunities to revitalize local economies and conserve biodiversity.

Nutritional and sensory evaluation of home-made soy yogurt

Nutritional and sensory evaluation of home-made soy yogurt

Effect of different strains on quality characteristics of soy yogurt: Physicochemical, nutritional, safety features, sensory, and formation mechanism

The purpose of the study was to explore effect of four different strains on quality characteristics of soy yogurt. The results showed that four strains were all related to the genus Lactobacillus and N1 was Lacticaseibacillus rhamnosus, N2 was Lacticaseibacillus paracasei, N3 was Lacticaseibacillus plantarum, and N4 was Lacticaseibacillus acidophilus. The result analysis of biochemical, sensory, nutritional, functional and safety properties of fermentation process and end products showed that the soy yogurt fermented with L. rhamnosus N1 had the highest isoflavone content and the lowest phytic acid content; the soy yogurt fermented with L. paracasei N2 had the highest content of free amino acids and oligosaccharides, the lowest content of trypsin inhibitors; the soy yogurt fermented with L. plantarum N3 had the lowest oil content; the soy yogurt fermented with L. acidophilus N4 had optimal functional properties. In summary, N4 was suitable as a fermentation strain for soymilk.

Physicochemical and sensory evaluation of lemon grass leaves extracts enriched soy yoghurt from soybeans (Glycine max) milk

AbstractThere are challenges in the utilization of soybean‐based foods due to undesirable associated flavors. This study aimed to prepare soybean based yoghurt with different amounts of lemon grass extract in the ratios of 0, 25, 50, 75, and 100 µL/L of soy yoghurt as shown by Figure 1. The Table 1 and 2 summarized results of different treatments of Soybeans based yoghurt analyzed for protein by Kjedhal method, fats by Soxhlet method, total ash by muffle furnace method. Soluble crude fiber was determined by dry oven method, pH, titratable acidity, syneresis and viscosity, by AOAC method, total phenolic compounds by spectrophotometric method. Sensory analysis was done by effective tests with 10 panelists using five hedonic scale tools. From the study, the results indicate that moisture content range from (89.3 to 89.6%); protein content (5.5−6.8%); fat (2.7−3.6%); total ash (0.43−0.53%); crude fiber (0.06−0.33%) and carbohydrate (0.59−0.93%). The level of pH range from 4.30 to 5.59; viscosity (2.85−3.17 pa.s); titratable acidity, (0.01−0.07 g\L) and synersis (6.44−7.56) and total phenolic compound (8.59−18.40 mg/g). Most of the parameters did not show any significant variations while the pH and total phenolic compounds varied significantly between the treatments. In addition, Figure 2 detailed sensory evaluation results of treatments and that the treatment with highest level of lemon grass extract was the most liked. In conclusion, incorporation of lemon grass extract can help improved the level of phenolic compounds and sensory properties of yoghurt.

A novel approach has been developed to produce pure plant-based gel soy yogurt by combining soy proteins (7S/11S), high pressure homogenization, and glycation reaction

This research sought to examine how the physicochemical characteristics of soy globulins and different processing techniques influence the gel properties of soy yogurt. The goal was to improve these gel properties and rectify any texture issues in soy yogurt, ultimately aiming to produce premium-quality plant-based soy yogurt. In this research study, the investigation focused on examining the impact of 7S/11S, homogenization pressure, and glycation modified with glucose on the gel properties of soy yogurt. A plant-based soy yogurt with superior gel and texture properties was successfully developed using a 7S/11S globulin-glucose conjugate at a 1:3 ratio and a homogenization pressure of 110 MPa. Compared to soy yogurt supplemented with pectin or gelatin, this yogurt demonstrated enhanced characteristics. These findings provide valuable insights into advancing plant protein gels and serve as a reference for cultivating new soybean varieties by soybean breeding experts.

The enhancement effect of mungbean on the physical, functional, and sensory characteristics of soy yoghurt

Vegetable drinks offer a convenient way to increase the daily intake of vegetables containing vitamins, antioxidants, and fiber. In this study, we discovered that mungbean milk serves as a carbohydrate source during fermentation using lactic acid bacteria (LAB) and enhances the nutritional value of vegetable yoghurt. Mungbean milk reduces pH while titratable acidity increases faster than soybean milk during fermentation. M0S, Soybean milk 100% with added sucrose exhibited the highest titratable acidity after 16 h of fermentation. The acetic acid content of all samples did not show significant changes during fermentation, but the lactic acid content increased. Proximate analysis showed no significant change during fermentation, regardless of the fermentation time and mixing ratio of mungbean to soybean milk. The sucrose content of samples except M0S decreased after 16 h of fermentation. Mungbean milk exhibited high antioxidant activity both before and after fermentation, while M0S showed the lowest antioxidant activity. The results of this study demonstrated the potential application of mungbean milk to improve fermented vegetable drinks using LAB functionally. Fermented mungbean milk yoghurt can be a valuable addition to a healthy and balanced diet for those who consume plant-based diets.

Effect of kefir and soy yogurt consumption on serum IGF-1 levels in young healthy women

Background:Milk and dairy product intake are associated with higher IGF-1 concentrations, a well-known factor promoting adverse events such as carcinogenesis. Different associations with high levels of IGF-I were found for dairy protein such as milk and derivatives, and soy protein. In this contest, fermented milk product (kefir)exhibits a growing number of health-promoting effects including stimulation of the immune system, and antimutagenic and anticarcinogenic activity, but there is a lack of data on healthy humans. Objectives: We aimed to determine the serum IGF-1 profiles of young healthy volunteers of the female sex after kefir or soy yogurt consumption during a Mediterranean diet.Materials and Methods: The study was conducted by monitoring the serum IGF-1 levels of female participants, following a normocaloric and normoproteic Mediterranean Diet, at the baseline (T0) and after 40 days of which the first 20 days (T1) consuming 125g of kefir, and the last 20 days (T2) consuming 125g of soy yogurt. Results: A total of 10 female participants were enrolled in the study (age=26.1± 2.9). The IGF-1 level was in the range of normality for all the participants except for one participant (T0=245 ± 61, T1=227 ± 58, T2= 239 ± 55). The mixed-model analysis revealed statistically significant differences in IGF-1 levels by diet (p=0.014; η2p=0.49). In particular, post-hoc analysis revealed a lower value after 20 days of kefir diet compared to both baseline (p= 0.014) and 40 days of diet (p=0.163). Conclusion: Caloric and protein intake have been suggested to influence circulating IGF-I, promoting carcinogenesis. Kefir consumption could improve the IGF-1 levels. Our data suggest that the inclusion of whole milk kefir in a normocaloric and normoprotein diet promotes blood IGF-1 levels in healthy young women as compared to soy yogurt consumption, reinforcing the beneficial effect of fermented milk on metabolic disorders. The interpretation of this result will need to be better investigated in further studies on large sample sizes.Keywords: IGF-1, Kefir, normocaloric diet, soy yogurt

Functional Properties of Soy Yoghurt with Red Dragon Fruit Substitution

This study investigated the antioxidant activity and lactic acid bacteria content of soy yoghurt with red dragon fruit substitution. Analysis included sensory evaluation, proximate analysis, quantification of antioxidant activity and estimation of total Lactic Acid Bacteria (LAB). Formula 3 with 35% red dragon fruit substitution was selected as the optimal formula. Proximate analysis showed water content of 92.75%, ash content of 0.23%, protein content of 0.48%, fat content of 3.08%, and carbohydrate content of 3.46%. The selected product had an increased antioxidant activity. In conclusion, soyghurt with red dragon fruit can increase the antioxidant activity of the product.

Response surface optimization of thermo-sonication conditions and taro mucilage concentrations for the preparation of soy yogurt

The present study embarked on developing soy yogurt utilizing soybean and taro mucilage. Box-Behnken Design (BBD) of Response Surface Methodology (RSM) was executed to optimize the ingredient and thermo-sonication conditions such as temperature (A: 40–60 °C), time (B: 5–15 min), and mucilage concentrations (0.1–0.3 g/100 mL) on the responses such as pH, acidity, syneresis, water holding capacity, viscosity, texture profile (firmness, adhesiveness, gumminess), and overall acceptability. The analyses showed that the soy yogurts have a titratable acidity (0.73 ± 0.43 % - 0.85 ± 0.58 %), pH (4.7 ± 0.40–4.93 ± 0.68), total soluble solid (26 ± 3.2 °Brix - 42.2 ± 4 °Brix), syneresis (26 ± 3.2 % - 39.98 ± 3.7 %), water holding capacity (36.33 ± 4.91 % - 55.7 ± 2.27 %), viscosity (1367.3 ± 2.98 mPa s - 2306.13 ± 3.21 mPa s), whitening index (76.1 ± 3.22–82.33 ± 2.18), firmness (14 ± 5 g - 26 ± 2 g), cohesiveness (13 ± 3.74 g s - 23.2 ± 2.88 g s), gumminess (0.7 ± 0.01 g - 1.8 ± 0.03 g), and overall acceptability (3.96 ± 0.16–4.54 ± 0.32). From the variance analysis, the R2 of eleven response variables is more than 0.85, which indicates the model explained a high proportion of variability. At 60 °C thermo-sonication temperature, 13 min thermo-sonication time, and 0.3 g/100 mL mucilage concentration, the optimal conditions recorded for 0.780 ± 0.21 % (titratable acidity), 4.701 ± 0.51 (pH), 10.986 ± 0.76 °Brix (total soluble solid), 27.886 ± 0.49 % (syneresis), 54.687 ± 0.38 % (water holding capacity), 1810.541 ± 5.75 mPa s (viscosity), 23.126 ± 0.45 (firmness), 16.945 ± 0.21 (cohesiveness), 1.485 ± 0.48 (gumminess), 81.764 ± 0.32 (whitening index), and 4.365 ± 0.42 (overall acceptability). Furthermore, the developed models' actual response and predicted values correlated with each other as the Residual Standard Error (RSE) values were ≤5 %. This suggests that our model can reliably guide the selection of optimal parameters for any combination of factors. Ultimately, the insights garnered from this study hold promise for the large-scale production of taro mucilage-based soy yogurt, offering a versatile and nutritious addition to the repertoire of dairy alternatives.

Formulations and assessments of structure, physical properties, and sensory attributes of soy yogurts: Effect of carboxymethyl cellulose content and degree of substitution

Soy yogurts present challenges, including absence of tender and slipperiness mouthfeel, and poor stability. This study aimed to investigate the impacts of carboxymethyl cellulose (CMC) with degrees of substitution of 0.7 (CMC0.7) and 1.2 (CMC1.2) at concentrations ranging from 0 % to 1.1 % on the stability, microstructure, rheology, tribology, and mouthfeel of soy yogurts. As the CMC concentration increased from 0 % to 0.3 %, soy yogurts displayed a coarser microstructure, decreased stability, and increased gel strength. As the concentration of CMC further increased from 0.5 % to 1.1 %, soy yogurts exhibited trends of a smoother microstructure, increased stability, and softer gel strength. Notably, soy yogurts with CMC0.7 demonstrated a superior water holding capacity (WHC) than soy yogurts with CMC1.2. Tribological measurements indicated that soy yogurts with CMC0.7 at a 0.7 % concentration had the lowest coefficient of friction (COF) value among most sliding speeds, showing a 23 % reduction compared to soy yogurts without CMC at a sliding speed of 10 mm/s. Moreover, sensory evaluation showed that soy yogurts with CMC0.7 at a 0.7 % concentration had the highest total score in mouthfeel evaluation. Therefore, the addition of CMC0.7 within the concentration range of 0.5 % to 1.1 % may produce stable and delicate yogurts.

Effects of co‐fermentation of Lactobacillus plantarum and inulin on beany flavor and physicochemical quality of soy yogurt in a multiple lactic acid bacteria fermentation system

AbstractBackground and ObjectivesSoybean yogurt is a nutritious, healthy, and environmentally friendly plant‐based beverage. However, the product's beany flavor and coarse texture have reduced consumer acceptance. The aim of this work was to investigate the effect of cofermentation of Lactobacillus plantarum and inulin on beany flavor and physicochemical quality of soy yogurt in a multilactic acid bacteria fermentation system.FindingsThe cofermentation of L. plantarum and inulin could effectively reduce the beany flavor compounds. With the increase of fermentation time, the lactic acid bacteria number gradually increased, the pH value decreased significantly (p < .05) from about 6.8 to 4.5, and the titratable acidity eventually reached about 50°T. When adding 0.04% (wt/vol) L. plantarum, as the rise of inulin from 3% to 9%, the color of soy yogurts showed golden yellow, the values of L*, a*, b*, and ∆E changed nonsignificantly (p > .05), and the viscosity, hardness, gumminess, cohesiveness, and adhesiveness significantly (p < .05) increased. When inulin was incorporated at 6% (wt/vol), the soy yogurt had the most outstanding water‐holding capacity (72.46%), dense and uniform protein gel microstructure, suitable adhesiveness (−37.55 g s), and optimal overall acceptance.ConclusionsSoy yogurt prepared from soymilk by adding 6% (wt/vol) inulin and inoculating 3% (wt/vol) lactic acid bacteria mixture (Lactobacillus bulgaricus:Streptococcus thermophilus = 1:4, wt/wt) and 0.04% (wt/vol) L. plantarum had the optimal overall acceptance.Significance and NoveltyThe results would provide a new reference method for the industrial production of low‐beany flavor and high‐quality soy yogurt.

Effect of lactic acid bacteria fermentation on extractable and non-extractable polyphenols of soybean milk: Influence of β-glucosidase and okara

Polyphenols and isoflavones are the main bioactive components of soybean. During traditional processing, many active compounds are lost because of filtration and discard of okara. However, reports on changes in phenolic compounds, especially bound phenolic compounds (BPC), during the fermentation of whole soybean milk (WSM) are few. In this paper, three lactic acid bacterias (LABs) with different β-glucosidase activities were used to evaluate the effect of β-glucosidase and different okara contents in soybean milk on the conversion of extractable and non-extractable polyphenols during fermentation. The results showed that the action of β-glucosidase improved the release of BPC and isoflavones. During WSM fermentation, the β-glucosidase-producing capacity of LABs strongly correlated with both the decrease in conjugated phenolic compounds and isoflavone glycosides, and the increase in free phenolic compounds and isoflavone aglycones. With the increase of okara content, the acid tolerance of Lactobacillus delbrueckii b8 was enhanced and the viability increased. During L. delbrueckii b8-mediated fermentation, the β-glucosidase activity of soy milk with high okara content (59.07 ± 1.48 U/mL) was 1.62 times that of soy milk with low okara content (36.43 ± 1.38 U/mL). As the okara concentration increased, the release of soybean polyphenols increased. Moreover, high okara content and high β-glucosidase activity mutually promote polyphenol conversion in soy yogurt. Therefore, WSM fermentation by β-glucosidase-producing LAB is a method for increasing the phenolic compound content in soymilk. This approach can offer a theoretical guide for efficiently utilizing soybean polyphenols and developing phenolic compound-rich soymilk.

Effect of fermentation of Danisco mixed lactic acid bacteria and single Bifidobacterium lactis HCS04-001 on metabolites of soy yogurt

Abstract In this study, the effects of Danisco mixed lactic acid bacteria and single Bifidobacterium lactis HCS04-001 fermentation on metabolites in soy yogurt were investigated. The main volatile metabolites in sample D fermented by Danisco mixed lactic acid bacteria were aldehydes, followed by alcohols and ketones. In contrast, the main flavor substances in sample SQ fermented by single Bifidobacterium lactis HCS04-001 were alcohols followed by aldehydes. L-Arginine, S-Adenosylhomocysteine, Glutamyltyrosine, Gly-Trp, Ser-Trp, Ile-Ser-Leu, Pro-Val-Leu etc. and D-Ornithine, Citrulline, Glutamylproline, organic acid were the main non-volatile differential metabolites that distinguished the soy yogurt samples. Arginine biosynthesis and glutathione metabolism were important pathways leading to differences in metabolic profiles. This study provides detailed insight into the metabolic properties of commercial Danisco mixed lactic acid bacteria and single Bifidobacterium lactis HCS04-001 fermentations, which will contribute to the development of soy yogurt with good nutritional and sensory qualities.

Evaluation of nutritional and physicochemical characteristics of soy yogurt by Lactobacillus plantarum KU985432 and Saccharomyces boulardii CNCMI-745

Nutritional yeast-produced soy yogurt has grown in demand, because of its unique nutritional and health benefits. It has low cholesterol, no lactose, and high levels of protein, probiotic yeast, vitamins, and minerals. In this work, Soymilk (12.5%) was prepared and fermented to produce soy yogurt. Growth curves, probiotic characteristics of Saccharomyces boulardii CNCMI-745 and Lactobacillus plantarum KU985432 were determined. The nutritional value of both yogurts was evaluated, including viable cell count, protein, vitamin B-complex, sugars, phenolic acids, and fatty acids, mineral content, stability, and storage. Analysis of the physicochemical composition of the yogurts included assessment of titratable acidity, antioxidant potential, viscosity, and moisture content. The probiotic viable count of the produced yogurts met the standards for commercial yogurts. S. boulardii CNCMI-745 displayed safety characteristics and high tolerance to heat, acid, and alkaline stress. The produced B vitamins increased in both yogurts. The total saturated fatty acids in Saccharomyces-yogurt decreased, while the unsaturated fatty acids increased. Saccharomyces-yogurt showed high antioxidant activity, phenolic acids, and crude protein content. Both yogurts demonstrated the same tendency for stability during 16 day-storage. In conclusion, using nutritional yeast in the production of soy yogurt increased its nutritional content more than probiotic lactic acid bacteria.

Development and Quality Evaluation of Non-Dairy Yogurts

Development of fermented vegetarian milk based food will be important to fulfill nutritional value of both elderly and individuals that require more energy intake. Objective: To develop non-dairy vegan yogurts from soy milk, oat milk and coconut milk in conjunction with lactic acid fermentation. Methods: Soy yogurt, oat yogurt and coconut yogurt was analyzed for crude protein, crude fat, crude fiber, carbohydrates, ash contents, moisture contents, titratable acidity, total soluble solids and pH analysis and to check its quality and acceptability by sensory evaluation for color, aroma, taste, consistency and acidity. Results: The mean values of crude protein of yogurts showed that soy yogurt contain more protein contents than other yogurts that was 6.0±0.1. The mean values for crude fat contents showed that maximum value 8.5±0.65 was noticed in the coconut yogurt and lowest value 3.1±0.1 was observed in soy yogurt. Mean values of crude fiber showed that fiber contents are present in more amount in soy yogurt (1.93±0.152). The mean maximum value for moisture contents was 84.43±4.007 that was noticed in soy yogurt and lowest value 66.69±0.164 was observed in oat yogurt. Mean values for carbohydrate in soy, oat and coconut yogurt was 9.28±0.01, 20.76±0.659 and 16.16±1.258. Mean results of overall acceptability of soy yogurt, oat yogurt and coconut yogurt was 7±0.35, 7.25±0.36 and 8±0.4 respectively. Conclusions: The study's findings demonstrated that it is possible to make plant-based yoghurt to meet the organoleptic needs of consumers, particularly those who are lactose intolerant or follow a vegan diet.

Texturing of Soy Yoghurt Alternatives: Pectin Microgel Particles Serve as Inactive Fillers and Weaken the Soy Protein Gel Structure.

Soy-based yoghurt alternatives were highly requested by consumers over the last few years. However, their texture does not always fulfil consumers' demands as such yoghurt alternatives are often perceived as too firm or too soft, sandy, or fibrous. In order to improve the texture, fibres, for example, in the form of microgel particles (MGP), can be added to the soy matrix. MGP are expected to interact with soy proteins, creating different microstructures and, thus, different gel properties after fermentation. In this study, pectin-based MGP were added in different sizes and concentrations, and the soy gel properties after fermentation were characterised. It was found that the addition of 1 wt.% MGP influenced neither the flow behaviour nor the tribological/lubrication properties of the soy matrix, regardless of the MGP size. However, at higher MGP concentrations (3 and 5 wt.%), the viscosity and yield stress were reduced, the gel strength and cross-linking density decreased, and the water-holding capacity was reduced. At 5 wt.%, strong and visible phase separation occurred. Thus, it can be concluded that apple pectin-based MGP serve as inactive fillers in fermented soy protein matrices. They can, therefore, be used to weaken the gel matrix purposely to create novel microstructures.

Soy-Ipoghurt as an antidiabetic on hiperglicemic animal modelling Rattus norvegicus

Treatment of Diabetes Mellitus (DM) is generally through optimizing a balanced diet. Soybeans and sweet potatoes have good antioxidants and can be developed as healthy foods for people with diabetes. Soybeans and sweet potatoes are processed into Soy-yoghurt. This study aims to determine the potential of soy yogurt as an antidiabetic in experimental animals, Rattus norvegicus induced by hyperglycemia, using Streptozotocin. This study used a experiment design with a total of 40 experimental animals. The research was conducted at the Medica Farma Husada Polytechnic Laboratory, Mataram, in 2022. The experimental animals that Streptozotocin (STZ) induced were then given Soy-yogurt orally at 3 ml and 3.5 ml doses. Experimental animals' Fasting Blood Glucose (FBG) levels were measured weekly using a Glucometer, while body weight (BW) was measured every three days. The results obtained were then analyzed statistically using the ANOVA test. The test results showed that there was a significant difference in blood sugar levels (p<0,05) in fasting given soy but no difference in BW (p>0,05). This study concludes that the provision of soybeans can affect the level of FBG of the experimental animals but does not affect the BW of the experimental animals.

Effects of cold storage time on the quality and active probiotics of yogurt fermented by Bifidobacterium lactis and commercial bacteria Danisco.

In this study, the commercial bacteria Danisco and Bifidobacterium lactis were used to ferment soy yogurt, and then the quality of yogurt and the number of active probiotics in yogurt during storage were investigated. The results showed that the total number of viable bacteria in soy yogurt increased first and then decreased, but all of them met the standard for the number of viable bacteria in probiotic foods. The content of protein, lipid, and total sugar in soy yogurt decreased gradually with the extension of storage time. The texture, water holding capacity, and rheological properties of soy yogurt were improved within 0-10 days, and there was no significant change after 15 days. However, brightness and whiteness of yogurt were significantly reduced. Based on realizing the reuse of soy whey, this study provided a theoretical basis for the research of the shelf life of soy yogurt. PRACTICAL APPLICATION: This study developed a soy yogurt with good quality and provided a theoretical basis for the study of the shelf life of soy yogurt. In addition, some technical support was provided for the reuse of soy whey.

Soy yoghurts produced with efficient GABA (γ-aminobutyric acid)-producing Lactiplantibacillus plantarum ameliorate hyperglycaemia and re-establish gut microbiota in streptozotocin (STZ)-induced diabetic mice.

Soy yogurt has been gaining popularity as a vegan food produced simply by soymilk fermentation with proper microbial manipulation. It is well known that soy containing rich isoflavones is beneficial for ameliorating hyperglycaemic disorders. Soy fermentation can improve the bioavailability of these precious nutrients. Lactiplantibacillus plantarum is one of the most abundant and frequently isolated species in soymilk manufacturing. Soy yogurts produced with efficient GABA (γ-aminobutyric acid)-producing L. plantarum and the deglycosylating activity of L. plantarum were functionally assessed in a STZ-induced hyperglycaemic mouse model. Hyperglycaemic mice were assigned into groups and treated with daily gavage of either dH2O, soymilk, soy yoghurts produced with high GABA-producing L. plantarum GA30 (LPGA30), low GABA-producing L. plantarum PV30 (LPPV30) or the soy yoghurts fortified with additional 30 mg g-1 GABA counterparts (GA + GABA and PV + GABA groups). Except the dH2O group, all soy yoghurt groups retained body weight with improved glucose homeostasis, glucose tolerance test results and renal tissue integrity, while the soymilk group shows partial benefits. Plasma GABA concentrations in the daily soy yoghurt-supplemented groups (LPGA30 and LPPV30) plateaued at 5 times higher than the average 0.5 μM in dH2O and soymilk groups, and their GABA-fortified soy yoghurt counterparts (GA + GABA and PV + GABA) groups were accountable for the restored plasma insulin levels. Gut microbiome analysis revealed dysbiosis in STZ-induced hyperglycemic mice of the dH2O group with breached out facultative anaerobic Proteobacteria over the normal phyla Firmicutes and Bacteroidetes. Restored gut microbiota with transitionally populated Actinobacteria was demonstrated in the LPGA30 group but not in the LPPV30 group. Soy yoghurts produced with efficient GABA-producing L. plantarum GA30 showed exceptional benefits in modulating gut microbiota with dominant genera of Enterococcus, Lactobacillus and Bifidobacterium, and the presence of some minor beneficial microbial communities including Akkermansia muciniphila, Butyricicoccus pullicaecorum, Corynebacterium spp. and Adlercreutzia spp. Efficient GABA-producing L. plantarum GA30 fermented soymilk to produce soy yoghurts that exhibit profound synergistic protections over rich soy isoflavones to restore pancreatic β-cell functions for insulin production in STZ-induced hyperglycaemic mice. Additionally, the probiotic role of GABA-producing L. plantarum in re-establishing healthy gut microbiota in hyperglycaemic mice implies a possible symbiotic relationship, awaiting further exploration.