Yogurt Dairy Research Articles

Preparation of fermented oat milk and evaluation of its modulatory effect on antigen-specific immune responses in ovalbumin-sensitized mice

ABSTRACT A growing number of people choose plant-based milk products to replace dairy for health reasons or veganism. Since fermentation is a promising method to improve the nutritional value of plant-based milk, this study aimed to establish the process of oat milk fermentation and to evaluate the effect of fermented oat milk (FOM) on modulating antigen-specific immune response in ovalbumin (OVA)-sensitized mice. The FOM was prepared by fermentation of oat milk with Streptococcus thermophilus, Lactobacillus bulgaricus and proteolytic L. rhamnosus. Addition of 1% glucose improved the process of fermentation. FOM was stable while stored at 4°C within seven days. Oral administration with FOM (0.4 and 2 g/kg body weight) did not alter the serum level of OVA-specific IgG and spleen index. However, FOM had comparable potency with commercial dairy yogurt to lower stimulation index, IL-2, IFN-γ and IL-4 production and to promote TGF-β and IL-10 secretion by OVA-stimulated splenocytes.

Physicochemical and rheological properties of commercial almond-based yoghurt alternatives to dairy and soy yoghurts

• The microstructure of almond yoghurts differed to soy and dairy yoghurts. • The protein in almond yoghurts formed a flocculated, particulate network. • Almond yoghurt viscoelasticity and lubrication were distinct from dairy yoghurts. • Two almond yoghurts displayed synaeresis, lower viscosity and higher recovery. • Almond yoghurt with fat from cashew and coconut behaved more like dairy yoghurt.

Effects of the substitution of cow’s milk with soymilk on the micronutrients, microbial, and sensory qualities of yoghurt

The consumption of imported dairy products is high especially in developing countries including Nigeria where little or no milk is produced locally which makes the products expensive, out of reach to common consumers and also inconvenient for lactose intolerance and vegans. Soymilk, as plant-based milk was substituted for cow’s milk in parts and in whole for the production of yoghurt and the effect of substitution was evaluated on the minerals, vitamins, microbial, and sensory properties of the products using the established methods. Significant differences (p < 0.05) exits among the yoghurt samples in the micronutrient contents. The soymilk substitution produced yoghurts with trace/macro mineral contents’ range of 0.14–28.50 mg/100 g and vitamin contents (ranged 0.02–0.43 mg/100 g) that were of comparable range of values with the yoghurt made with 100% cow’s milk (0.21–29.60 mg/100 g minerals and 0.05–0.58 mg/100 g vitamins). Generally, no significant difference (p < 0.05) was observed in most of the sensory attributes evaluated (range 8.00–8.01) in the entire samples (except in the 100% soymilk yoghurt). The microbial analysis proved the safety of the entire products for consumption. These showed the positive effect of substituting soymilk for cow’s milk at all the levels used, thus, the lactose intolerance and vegans can find alternative to dairy yoghurt in the 100% soymilk substitution and enjoy the functional health benefits of yoghurt. Also, the total dependence on importation of dairy milk and cost of production of composited milk yoghurt could be reduced to improve the nation’s economy and make the product economically accessible to common man.Graphical abstract

Moringa oleifera Seeds Characterization and Potential Uses as Food.

Despite the fact Moringa oleifera (MO)-based foods present a very good and nutritionally well-balanced composition, they face some issues related to seed bitterness, which is the most challenging barrier to consumer acceptance. Different processing methods were tested to produce MO toasted seeds, MO-based beverage, and yoghurt-like products which were chemically and rheologically analyzed. The protein content ranged from 3.68% in the beverage, to 14.73% in the yoghurt and 40.21% in MO toasted seeds. A totally debittered beverage could not be accomplished, but the MO yoghurt-like showed a very nice flavor. Nutrition claims for minerals in toasted seeds could be considered for magnesium, phosphorus, iron, copper, zinc, and manganese, which confirms the M. oleifera seed richness in several minerals. The MO beverage presented less extended shear-thinning behavior (17.4 Pa·s) than commercial vegetable beverages and two pulse-based beverages developed in a previous study. The MO yoghurt-like product showed a gel structure similar to the dairy yoghurt, making it a promising new plant-based alternative. Further work must be performed in the future to debitter more efficiently the raw seeds to achieve a more pleasant MO-based beverage. The developed MO seed-based products may settle another font of high protein plant-based food.

Rheological, structural, and water-immobilizing properties of mung bean protein-based fermentation-induced gels: Effect of pH-shifting and oil imbedment

The objective of this study was to investigate the impact of pH-shifting and oil inclusion on the textural properties of plant protein-based fermentation-induced gels resembling dairy yogurt in consistency. Gels were formed by pH12-treated or native mung bean protein (MBP) with or without emulsified coconut oil (3% w/v) and transglutaminase (0.1% w/w protein) during fermentation at 43 °C for 8 h. Quinoa flour hydrolysate was used to modulate the MBP gel network. Creep-recovery and viscoelasticity (Gʹ/Gʹʹ) tests showed that gels prepared with pH12 treated MBP were less deformable and stiffer than native MBP gels. The pH12 treated MBP gels also exhibited superior hardness and water-holding capacity over the native MBP gels. Consistently, the pH12 gels displayed more compact and denser network structures, and oil emulsion droplets as well as transglutaminase further contributed to such packing effect. 1H-LF-NMR confirmed less mobility of bulk water in pH12 gels compared with native gels.

Production and Characterization of Yogurt-Like Fermented Beverage Based on Camelina (Camelina sativa L.) Seed Press Cake

Plant-based fermented beverages are growing in popularity due to the rise in vegetarianism, health trends and ethical concerns. In this study, camelina (Camelina sativa L.) seed press cake (CPC, 15% and 20% w/w) was fermented using yogurt starter culture. The physicochemical properties of the samples, including pH, total acidity, color, viscosity, texture and rheological properties were investigated. Moreover, the lactic acid bacteria (LAB) viability, bioactive compounds and antioxidant activity were determined. During fermentation and 28-day refrigerated storage, the samples achieved a mean viable bacterial count of at least 1010 CFU/g, which is higher than the recommended bacteria level for traditional dairy yogurt (106 CFU/g). A significant acidification, consumption of reducing sugars, increase in free amino acids and polyphenolics was observed. In addition, CPC-based fermented samples showed good antioxidant potential. Textural and rheological characteristics were similar to dairy yogurt. Moreover, fermentation improved the sensory attributes of CPC, meeting consumers’ acceptance criteria. Thus, the study indicated that fermentation had a marked effect on the physicochemical, microbiological and functional properties of CPC. Therefore, the fermented CPC-based beverage has the potential to be a valid, value-added and novel alternative to dairy-based yogurt.

Novel Millet-Based Flavored Yogurt Enriched With Superoxide Dismutase.

Superoxide dismutase (SOD) is an important antioxidant enzyme with different physiological functions, which can be used as a nutritional fortifier in food. Cereal-based fermented products are becoming popular worldwide. In this study, novel millet-based flavored yogurt enriched with SOD was developed. Lactiplantibacillus plantarum subsp. plantarum was screened, which manufactured SOD activity of 2476.21 ± 1.52 U g−1. The SOD content of millet yogurt was 19.827 ± 0.323 U mL−1, which was 63.01, 50.11, and 146.79% higher than that of Bright Dairy Yogurt 1911, Junlebao and Nanjing Weigang, respectively. Fifty-four volatile flavor substances and 22,571 non-volatile flavor substances were found in yogurt. Compared to traditional fermented yogurt, 37 non-volatile metabolites in yogurt with millet enzymatic fermentation broth were significantly upregulated, including 2-phenyl ethanol, hesperidin, N-acetylornithine and L-methionine, which were upregulated by 3169.6, 228.36, 271.22, and 55.67 times, respectively, thereby enriching the sensory and nutritional value of yogurt. Moreover, the manufacture of unpleasant volatile flavor substances was masked, making the product more compatible with consumers' tastes.

Altering almond protein function through partial enzymatic hydrolysis for creating gel structures in acidic environment

Protein inadequacy is the major problem for most plant-based dairy yoghurt substitutes. This study investigated three limited degree of hydrolysis (DH: 1%, 5%, and 9%) of almond protein and the combined effect of DH and hydrolysed almond protein (HP) to non-hydrolysed almond protein (NP) ratios (HP/NP: 40:60, 20:80, 10:90 and 5:95) on the physicochemical properties of resulting fermentation induced almond-based gel (yoghurt). The gel microstructure, particle size, firmness, pH, water holding capacity (WHC), lubrication, flow, and gelation characteristics were measured and associated with the DH, composition, and SDS-PAGE results. The results show significant differences in gel samples with the same HP/NP (40:60) ratio of protein but different protein DH. A higher DH (9%) resulted in samples with lower hardness (6.03 g), viscosity (0.11 Pa s at 50 s-1), cohesiveness (0.63) and higher friction (0.203 at 10 mm/s) compared to sample with 1% DH with higher hardness - 7.34 g, viscosity at 50 s−1 - 0.16 Pa s, cohesiveness - 0.86 and friction at 10 mm/s - 0.194. Comparing samples with the same DH (5%) but different HP/NP ratios showed smaller coarse microgel particles (21.36 μm) and lower hardness (7.17 g), viscosity (0.14 Pa s at 50 s−1) and friction value (0.189 at 10 mm/s) in samples with high HP/NP (40:60) compared to sample with low HP/NP (5:95) that contained significantly large coarse microgel particles (34.61 μm) with the gel being very hard (9.38 g), highly viscous (0.32 Pa s at 50 s−1), and less lubricating (0.220 at 10 mm/s).

Chemically acidified, live and heat-inactivated fermented dairy yoghurt show distinct bioactive peptides, free amino acids and small compounds profiles

Previous studies found variations in the health-promoting effects of consuming different dairy products. This study aims at investigating the chemical composition of microbial fermented yogurt, chemically acidified yogurt and whole milk to understand the differences in the effects these products exert on human health. For this purpose, peptides and small compounds present in the products were examined using a combination of liquid chromatography mass spectrometry and nuclear magnetic resonance spectroscopic techniques. Results revealed that each product had its own characteristic peptide, free amino acid and small compound profile, and database search for bioactivity disclosed that fermented yogurt manufactured using a starter culture is associated with a higher bioactivity potential than chemically acidified yogurt or whole milk. Additional cold storage (14 days) further enhances the bioactivity potential of fermented yogurt while heat-inactivation, ensuring long shelf-life, modulates the proteins available for proteolysis and thereby the peptide profile generated.

Vegan Alternatives to Processed Cheese and Yogurt Launched in the European Market during 2020: A Nutritional Challenge?

Vegan alternatives to cheese (VAC) and yogurt (VAY) are fast-growing markets in Europe due to the increasing interest in plant-based alternatives to dairy products. This study aimed to take a closer look at the year 2020 and accordingly retrieved the nutritional information of dairy cheese and yogurt and their vegan counterparts for comparison. It was found that VAY (n = 182) provide more energy, total fats, and carbohydrates than dairy yogurt (n = 86), while saturated fatty acids (SFAs), sugars, and salt were not different between the two categories. Compared to dairy products (25.6%), 72.9% of the alternative products were declared low/no/reduced allergen, hence providing a larger spectrum of products to respond to consumers’ requirements. VAC (n = 114) showed high versatility of form compared to dairy (n = 115). Nutritionally, VAC have higher total fats, SFAs, and carbohydrates, but lower protein, salt, and sugar than dairy cheese. Food developers will continue to look for clean label solutions to improve the nutritional values of vegan products through the incorporation of natural ingredients, besides enhancing their taste and texture to appeal to flexitarians.

Comparison of the Effects of Native and Commercial Probiotic on Gluten Degradation

Background and Objectives: The main treatment for celiac disease is a gluten-free diet. Gluten infection occurs in 55%-32% of these patients, which can cause symptoms in these patients. Many patients with celiac disease are dissatisfied with a gluten-free diet and are interested in a non-dietary alternative treatment. Methods: In this study, probiotic samples of local dairy (milk, yogurt, and cheese) from Iran were collected in sterile conditions and after enzymatic extraction using a lysis buffer and a sonication method for enzyme activity of prolyl endopeptidase and aminopeptidase N were evaluated. Results: The highest absorption rate for Z-Gly-Pro-4-nitroanilide substrate that performs the evaluation of prolyl endopeptidase enzyme, respectively, for strains C10-1 (L. pentosus), B6-1 (L. fermentum), C5-2 (L.paracasei), Y5 (L.paracasei) and C11-1 (L. pentosus) and in relation to Leu-p-NA which assesses aminopeptidase N The highest uptake was observed for strains K1 (L. helveticus), B8-2 (L. plantarum), Y5 (L.paracasei), P2-3 and P35 (L. plantarum), respectively. All of the above strains showed significantly different uptake than the negative control containing buffer and substrate (P&lt;0.05). Finally, the 16s rRNA sequence of the isolated strains was registered in NCBI database. Conclusion: The results of the present study showed that number of native Iranian probiotics have effective activity of prolyl endopeptidase and aminopeptidase N which can be used as a selective combination for gluten degradation and to help celiac patients.

Cinnamomum zeylanicum and Curcuma longa incorporated dairy yoghurts with hindered glycaemic properties for healthy people

This study mainly compare glycaemic responses of a control yoghurt (typical dairy yoghurt) against two novel yoghurt products with added spices oleoresins (Cinnamon yoghurt - Cinnamomum zeylanicum , turmeric yoghurt - Curcuma longa ) using 16 healthy volunteers in a randomized crossover study. Blood glucose concentrations were measured at fasting state and 30, 45, 60, 90, 120 min following the ingestion, using a Blood Glucose Monitoring System and blood glucose response curves were plotted. Nutritional and physicochemical properties were also compared and no significant differences ( P > 0.05) were observed between novel yoghurts and the control within the storage period. Significant reductions in peak blood glucose concentration and area under the curve (AUC) ( P < 0.05) for both novel products compared to standard dairy yoghurt was observed; revealing the reduction of glycaemic impact by spice ingredients. Peak reductions of glucose concentration for cinnamon yoghurt was 9.61%, for turmeric yoghurt was 9.26%; they were considerably lower compared to the control. Mean peak serum glucose concentration for control, cinnamon yoghurt and turmeric yoghurt were (113.38 ± 6.39), (102.50 ± 6.00), (102.88 ± 5.38) mg/dL respectively and mean AUC were (11 951 ± 523), (11 012 ± 611), (10 941 ± 530) ((mg/dL)*min) respectively. Hence novel yoghurt products are proven to be excellent sources in reducing postprandial blood glucose responses.

Development of a yoghurt alternative, based on plant-adapted lactic acid bacteria, soy drink and the liquid fraction of brewers' spent grain.

With consumers becoming more aware of sustainability, healthier lifestyles and animal welfare, plant-based food products as alternatives to dairy products have become a fast-growing industry in the last decade, and an increasing number of plant-based products are showing up on the markets. With over 88 million tons of food wasted in Europe annually, a sustainable alternative to dairy could be to use side streams for new products. Here, we tried to develop a plant-based yogurt alternative based on three ingredients: commercial soy drink and a liquid fraction of brewers' spent grain fermented with plant-adapted lactic acid bacteria. Analysis of the content and properties of the fermented product were compared to a commercial plant-based yoghurt-like product and a commercial dairy yoghurt. Results from the project show that fermentation of a commercial soy drink containing 20% of the liquid fraction of brewers' spent grain results in a product with texture and sensory characteristics that mimics a dairy yogurt.

Nutritional and Rheological Features of Lentil Protein Isolate for Yoghurt-Like Application.

The substitution of animal protein with proteins of plant origin is a viable way to decrease the negative impact caused by animal husbandry on the environment. Pulse consumption has been widely promoted as a nutritious contribution to protein supplementation. In this study, an emulsion of lentil (Lens culinaris) protein isolate is fermented with lactic acid bacteria (LAB) to manufacture a yoghurt alternative and the techno-functional properties compared to a dairy- and a soy-based product with similar protein contents. The yoghurt-like products are subjected to large and small deformation analysis, quantification of fermentable oligosaccharides, disaccharides, monosaccharides and polyols (FODMAP), water holding capacity tests, protein profile analysis and the gel structure is visualised by confocal laser scanning microscopy (CLSM). The lentil yoghurt alternative shows good water holding capacity, high firmness and consistency values in large deformation analysis, with cohesiveness and viscosity not significantly different from that of dairy yoghurt. The high gel strength and rigidity of the lentil yoghurt gels measured by small deformation analysis is well-reflected in the dense protein matrix in the CLSM graphs. FODMAP content of the lentil yoghurt is very low, making it suitable for consumption by irritable bowel syndrome (IBS) patients. Our results show that lentil protein isolate is an excellent base material for producing a plant-based yoghurt alternative.

Nutritional properties and health aspects of pulses and their use in plant-based yogurt alternatives.

Plant-based yogurt alternatives are increasing in market value, while dairy yogurt sales are stagnating or even declining. The plant-based yogurt alternatives market is currently dominated by products based on coconut or soy. Coconut-based products especially are often low in protein and high in saturated fat, while soy products raise consumer concerns regarding genetically modified soybeans, and soy allergies are common. Pulses are ideally suited as a base for plant-based yogurt alternatives due to their high protein content and beneficial amino acid composition. This review provides an overview of pulse nutrients, pro-nutritional and anti-nutritional compounds, how their composition can be altered by fermentation, and the chemistry behind pulse protein coagulation by acid or salt denaturation. An extensive market review on plant-based yogurt alternatives provides an overview of the current worldwide market situation. It shows that pulses are ideal base ingredients for yogurt alternatives due to their high protein content, amino acid composition, and gelling behavior when fermented with lactic acid bacteria. Additionally, fermentation can be used to reduce anti-nutrients such as α-galactosides and vicine or trypsin inhibitors, further increasing the nutritional value of pulse-based yogurt alternatives.

A Cross-Sectional Audit of Nutrition and Health Claims on Dairy Yoghurts in Supermarkets of the Illawarra Region of New South Wales, Australia.

Health and nutrition claims are used by consumers to guide purchasing decisions. In consequence, monitoring and evaluation of such claims to ensure they are accurate and transparent is required. The aim of this study was to investigate the use of nutrition and health claims on dairy-yoghurt products within select Australian supermarkets and assess their compliance with the revised Food Standards Code (FSC). Nutrition, health, and related claims on yoghurt products were assessed in a cross-sectional audit of five supermarkets in the Illawarra region of New South Wales. Claim prevalence, type, and compliance were assessed and products were compared against current rating measures. A total of n = 340 dairy yoghurt products were identified. Most products (97.9%) carried at least one nutrition and/or health claim, with nutrition-content claims (93.9%) the most prevalent. Most products (n = 277) met the nutrient profiling scoring criterion; while 87.9% of products did not carry the health star rating. Almost all claims surveyed (97.4%) were compliant with the FSC. Health and nutrition claims are highly prevalent across yoghurt categories, with the majority of these compliant with regulations. The ambiguity surrounding the wording and context of claims challenges researchers to investigate consumers’ interpretations of health messaging within the food environment.

Probiotic enriched fermented soy‐gel as a vegan substitute for dairy yoghurt

Probiotic enriched fermented soy‐gel as a vegan substitute for dairy yoghurt

Microbiological, Physicochemical, and Immunological Analysis of a Commercial Cashew Nut-Based Yogurt.

Nut-based milks and yogurts are gaining popularity, but may not offer the same benefits as dairy yogurts to consumers. Cashew nuts often cause severe allergic reactions, and cashew nut allergens are stable to several types of processing. To compare its characteristics to dairy yogurt and characterize the effects of fermentation on the Ana o 1–3 cashew nut allergens, a commercial yogurt made from cashew nuts (Cashewgurt) was evaluated for microbiological, physiochemical, and immunological properties. Average counts for lactobacilli and Streptococcus thermophilus were greater than 10 million colony forming units per milliliter, indicating the capacity to provide a health benefit. Cashewgurt pH and viscosity values were comparable to cow milk yogurts, and it was off white in color. SDS-PAGE analysis indicated a clear reduction in Ana o 1 and 2, and immuno-assay with polyclonal anti-cashew IgG antibody and cashew-allergic IgE indicated an overall reduction in allergen content. In contrast, SDS-PAGE, mass spectrometry, immunoblot, and ELISA all revealed that Ana o 3 was relatively unaffected by the fermentation process. In conclusion, Ana o 1 and Ana o 2 are sensitive to degradation, while Ana o 3 survives lactic acid bacterial fermentation during yogurt production. The analysis presented here indicates that cashew nut yogurt is not suitable for those with cashew nut allergy.

A Novel Approach to Structure Plant-Based Yogurts Using High Pressure Processing.

Current plant-based yogurts are made by the fermentation of plant-based milks. Although this imparts fermented flavors and probiotic cultures, the process is relatively longer and often leads to textural issues. The protein content of these plant-based yogurts is also lower than their dairy counterparts. To overcome these challenges, this paper explores the high pressure processing (HPP) of plant protein ingredients as an alternative structuring strategy for plant-based yogurts. Using mung bean (MB), chickpea (CP), pea (PP), lentil (LP), and faba bean (FB) proteins as examples, this work compared the viscosity and viscoelastic properties of high pressure-structured (600 MPa, 5 min, 5 °C) 12% (w/w) plant protein gels without, and with 5% (w/w) sunflower oil (SO) to commercial plain skim and whole milk Greek yogurts and discussed the feasibility of using HPP to develop plant-based yogurts. HPP formed viscoelastic gels (G’ > G’’) for all plant protein samples with comparable gel strength (G’~102–103 Pa; tan δ~0.2–0.3) to commercial dairy yogurts. The plant protein gel strength decreased in the order: CP~CPSO~LP~LPSO > MBSO~PPSO~FB~FBSO > PP >> MB. Modest addition of sunflower oil led to little change in viscoelastic properties for all plant protein samples except for MB and PP, where gel strength increased with incorporated oil. The emulsion gels were also more viscous than the hydrogels. Nonetheless, the viscosity of the plant protein gels was similar to the dairy yogurts. Finally, a process involving separate biotransformation for optimized flavor production and high pressure processing for consistent texture generation was proposed. This could lead to high protein plant-based yogurt products with desirable texture, flavor, and nutrition.

EFFECT OF GINGER EXTRACT ON THE VIABILITY OF LACTIC ACID BACTERIA AND SENSORY CHARACTERISTICS OF DAIRY YOGHURT AND SOY YOGHURT

Yoghurt is usually produced from cow milk which is unsuitable for vegetarian diet. Chemical preservative used for its preservation may have adverse effect on the lactic acid bacteria. This research was designed to evaluate the effect of ginger extract on the viability of lactic acid bacteria, physico-chemical property and sensory attributes of bio preserved functional yoghurt produced from dairy milk and soy milk during storage at refrigerated temperature. The result obtained showed that yoghurt produced from soy milk (5.67 – 7.52 CFU/ml) had higher lactic acid bacteria count than yoghurt from dairy milk (4.71 – 7.31 CFU/ml) throughout the period of storage. Ginger extract was more active against fungi in dairy yoghurt than (0 - 5.09 CFU/ml) soy yoghurt (0 – 5.29 CFU/ml). The pH was generally lower in dairy yoghurt (4.29 - 4.67) than soy yoghurt (4.69 – 5.14) while the titratable acidity was higher in dairy yoghurt (1.30 – 2-01%) than soy yoghurt (0.7 – 1.54%). Addition of ginger extract improved the texture and flavour of soy yoghurt. It is therefore suggested that functional yoghurt with good sensory attributes can be produced from soy milk and dairy milk using ginger extract as bio-preservative.