Quality Of Yogurt Research Articles

The Effect of Probiotic Starter Culture Variation on the Quality of Yogurt Based on Indonesian National Standard

The Effect of Probiotic Starter Culture Variation on the Quality of Yogurt Based on Indonesian National Standard

Effects of Dioscorea opposita mucilage addition on the physicochemical properties, texture, and stability of set-type yogurt

Dioscorea opposita mucilage (DOM), a polysaccharide-protein polymer with antioxidant activity, can be served as a natural ingredient in nutritional yogurts. The effects of DOM addition at different concentrations (2%, 4%, 6%, 8%, 10% and 12% w/w) on the total number of lactic acid bacteria, pH, titratable acidity, syneresis, viscosity, texture, color and sensory evaluations of full-fat yogurts and skimmed yogurts during 21 days storage at 4 °C were investigated. The results suggested that DOM could improve the growth of LAB, strengthen the network and gelation of yogurt, and thicken the dispersion, which led to the significant decrease in pH and cohesiveness, and drastic increase in the syneresis, firmness and adhesiveness. Additionally, sensory evaluation revealed that the overall liking scores of full-fat yogurts (8.1–8.7) were higher than those of skimmed yogurts (7.9–8.3), which exhibited strong correlations with firmness and viscosity of set-type yogurts. Although DOM addition affected the sensory undesirably, such as creaminess, the thickness and overall liking were improved, especially for the skimmed yogurts. In summary, 8% w/w DOM could effectively improve the texture, quality and stability of set-type yogurts. This study provides new applications in functional dairy products and promotes the value of the by-products of D. opposita.

Chia Seed Mucilage as a Functional Ingredient to Improve Quality of Goat Milk Yoghurt: Effects on Rheology, Texture, Microstructure and Sensory Properties

Chia Seed Mucilage as a Functional Ingredient to Improve Quality of Goat Milk Yoghurt: Effects on Rheology, Texture, Microstructure and Sensory Properties

The Effect of Lactiplantibacillus plantarum SHY130 and Konjac Glucomannan on the Physicochemical, Antioxidant, and Sensory Properties of Stirred Yogurt.

The impact of konjac glucomannan (KGM)-based synbiotics on yogurt quality is not well understood. This study investigated the effects of a synbiotic mixture of KGM and the selected probiotic Lactiplantibacillus plantarum SHY130 on the physicochemical, antioxidant, and sensory properties of yogurt. The results showed that KGM significantly promoted the growth of Lactiplantibacillus plantarum SHY130. The synbiotics dramatically enhanced the count of lactic acid bacteria in yogurt during the 14 days of storage. Texture analysis indicated that the synbiotic supplement had no impact on springiness and cohesiveness but resulted in notable reductions in hardness, gumminess, and chewiness. The synbiotics did not significantly affect the water-holding capacity and syneresis. While the synbiotics initially decreased yogurt viscosity, it increased with storage time. Furthermore, the synbiotics significantly improved the yogurt's antioxidant capacity. Additionally, the supplementation of the synbiotics did not adversely affect sensory properties, although the synbiotics containing 0.02% KGM negatively impacted overall acceptability. Overall, these findings elucidate the effects of KGM-based synbiotics on yogurt quality, providing a foundation for developing novel synbiotic yogurt products.

Quality Assessment of Greek-Style Set Yoghurt Fortified with Extracted and Dried Australian Native Fruit, Illawarra Plum.

The Illawarra plum (IP) is native to Australia and has been used as a bush food for centuries. With rich phytochemicals and natural pigments, IP has the potential to be an added ingredient to improve the physicochemical properties of food, including yoghurt. This study prepared dried IP powders through vacuum drying (VD) and freeze drying (FD), produced extracts from these dried powders, and fortified them into Greek-style set yoghurt. The changes in colour, pH, titratable acidity (TA), syneresis, total soluble solids (TS), and phytochemicals were measured throughout a chilled storage period of 28 days. The results showed that FD and FD extract could provide a stable, distinct pink colour to yoghurt. IP powders and their extracts improved TS content and, thus, the consistency of yoghurt. Compared to the control, VD, FD, and FD extract of IP did not significantly affect the level of acidity or syneresis after 28 days of chilled storage. Yoghurt fortified with FD and FD extract had the greatest level of phenolics, anthocyanins, and radical scavenging antioxidant activities. This study revealed that IP powders and their extracts can positively improve the physicochemical properties of Greek-style set yoghurt. FD powder is recommended over its extract to fortify this yoghurt, as it can be cost-effectively prepared by freeze drying and then grinding the fresh fruit into powder. Future studies are needed to evaluate other variables in yoghurt preparation, including the concentration of IP and strains of yoghurt culture. Further, the consumer perception of sensory quality and acceptability of yoghurt fortified with FD IP powder should be investigated.

Effect of different types of pectin on the physicochemical, rheology, and sensory properties of low-fat yogurt

Abstract Low-fat yogurt has been defined to contain fat content of not more than 2.0 percent as per The Code of Federal Regulations, FDA, U.S. Nevertheless, the reduced fat content affects the physicochemical properties of yogurt by weakened texture, poor body, syneresis, and sensory quality. This is due to fat globules that govern the protein linkages that are responsible for the yogurt’s texture and firmness. The objectives of this study are to evaluate the physicochemical, rheology properties, and to determine the sensory properties and overall acceptability of low-fat yogurt enriched with different types of pectin. Pectin helps improve the gel characteristics, rheology, and microstructure of set yogurt through interactions with the casein network. Two different types of pectins are used which are low-methoxyl pectin (LMP) and high-methoxyl pectin (HMP). For each type, two different concentrations were used which are 0.5% and 1.0% for both types of pectin. Analysis such as pH measurement, titrable acidity, color measurement, water holding capacity measurement, syneresis measurement, viscosity measurement, microbial analysis, and scanning electron microscopy were conducted. The results from the analysis above were subjected to two-way ANOVA and post hoc Tukey’s test. The addition of LMP (0.5% and 1.0%) showed a positive effect on the quality of yogurt with primary attributes compared to the pectin added with HMP and control sample. In conclusion, the low-fat yogurt had a positive effect due to the enrichment of the pectin. Sample 4 which is the low-fat yogurt with 1.0% of LMP showed better properties compared to other samples.

Optimizing skim milk yogurt properties: Combined impact of transglutaminase and protein-glutaminase

The lack of fat in yogurt can lead to alterations in taste and whey separation, reducing consumer acceptance. In this study, the feasibility of enhancing the quality of skim milk yogurt through a combination of transglutaminase (TG) and protein-glutaminase (PG) was investigated. The combination of TG and PG resulted in simultaneous cross-linking and deamidation of CN micelles, with PG deamidation taking priority over TG cross-linking, leading to higher solubility and lower turbidity of milk proteins compared with TG alone. When 0.06 U/mL TG and 0.03 U/mL PG were added, firmness and viscosity indexes significantly increased by 38.26% and 78.59%, respectively, as compared with the control. Microscopic images revealed increased cross-linking with CN and filling of cavities by smaller submicelles in the combination of TG and PG treatment. Furthermore, the combination of TG and PG resolved issues of rough taste and whey separation, leading to improved overall liking. This study highlights the benefits of using both enzymes in dairy production and has important implications for future research.

Pengaruh Penambahan Inulin terhadap Mutu Sensorik, Kandungan Serat dan Daya Terima Yoghurt

Yogurt is a functional food that contains probiotic bacteria beneficial for health. The addition of inulin fiber is considered to increase the fiber content of the product, thereby enhancing its benefits. The purpose of this study was to determine the effect of inulin addition on the organoleptic quality, fiber content, and acceptability of yogurt. The study used a completely randomized design (CRD) with one control, three treatments, and two repetitions. The amounts of inulin added were 7.5, 10, and 12.5 grams per portion. Data were analyzed using the Kruskal-Wallis test at the 5% level. Organoleptic test results showed that the average level of panelists' preference for taste, aroma, color, and texture was highest in treatment F2, with the addition of 7.5 grams of inulin. The test results indicated that the best treatment in terms of sensory taste, aroma, color, and texture was treatment F2, with the addition of 10 grams of inulin. There was a significant effect of inulin addition on the texture and taste of yogurt (p<0.05). The acceptability of yogurt with inulin addition was 92.8%. The fiber content test revealed a fiber content of 12.78%. It can be concluded that the addition of inulin to yogurt affects the organoleptic qualities of texture and taste and increases fiber content and product acceptability. The best results were obtained with the addition of 10 grams per portion. Further research is recommended to evaluate the number of bacteria and the shelf life of yogurt with added inulin.

Initial Development of Lamota (Salicornia europae) Yogurt As a Functional Drink

Salicornia europae is a marine plant that grows in coastal areas and tides. In Sumbawa, this plant lives in the former area of ponds and usually called as lamota. S. europae contains beneficial ingredients such as iodine, minerals, vitamins, antioxidants, unsaturated fatty acids, and sugars. Marine plant innovations in S. Europae, which is rich in iodine into processed yogurt, has not been well explored. This study aimed to develop the processing of lamota into functional yogurt drink. Complete Randomized Design (CRD) was used in this experiment with a single factor of 6 levels of lamota concentration. Iodine content, ash content, pH and scoring test were carried out to find out the best quality of the lamota yogurt. The results showed that the iodine content of the product was 29.01 mcg / g dry weight and ash content was 10.59%. The pH showed that the addition of lamota minimally affected the pH of the yoghurt. In the organoleptic test found that 25% addition of lamota extract was the most preferrable concentration compared to 5, 10, 15, and 20% based on the color, taste, texture, aroma. Panelist describe the 25% lamota addition has greenish color, a little bit salty, watery texture, and green aroma. Based on the iodine content and the best consumers acceptance the yogurt with 25% addition of lamota could be categorized as a rich in iodine drink and a promising product to improve the functional characteristics of yogurt as well develop a value added local marine commodity with unique flavor.

Pengaruh Penambahan Biji Chia dan Selasih Terhidrasi terhadap Sifat Fisikokimia, Sensori, dan Mikrobiologis Yoghurt

Chia and basil seeds are a plant-based source that possess unique characteristic, including the ability to form a gel when hydrated due to polysaccharide layer on outer seeds can absorb water This property can be applied to food products that may easily suffer texture damage such as yogurt. Therefore, further research is needed to determine the potential of chia and basil seeds as a hydrocolloid source that can affect yogurt characteristics and total lactic acid bacteria (LAB). Chia and basil seeds in this study were each processed into two treatments: flour and hydration of whole seeds (1:30). Each treatment was added to yogurt formulation with concentration: 0, 1, 2, and 3% (w/v), then evaluated by preference test to determine selected formulation. Two formulations that were organoleptically preferred by panelists were yogurt with hydrated chia 2% and hydrated basil 3% according to hedonic rating test. The selected formulations were proximate content analysis, syneresis, viscosity, and total LAB. The addition of chia and basil seeds into yoghurt had significant effects on syneresis and viscosity at a significance level of 5%. The syneresis of yogurt with hydrated chia 2% was 1.37±0.21% while the syneresis of yogurt with hydrated basil 3% was 0.58±0.05% which was lower than control 2.44±0.24%. Viscosity of yogurt with hydrated chia 2% was 3808.33±38.19 cP and yogurt with hydrated basil 3% was 4175.00±25.00 cP, which was higher than control 3116.67±28.87 cP. Total LAB in chia yogurt reaching 1.1 109 CFU/g and basil yogurt reaching 1.2 109 CFU/g was higher than control 8.7 107 CFU/g. Overall, the addition of chia and basil seeds improved the quality of yogurt.

Comparison of the physicochemical property and volatile flavour compounds of yoghurt made from ultra-pasteurised and membrane-filtered milk

In this study, we aimed to compare and contrast the physicochemical and flavour attributes of yoghurt crafted from ultra-pasteurised (UPM-yoghurt) and membrane-filtered milk (MFM-yoghurt). The results indicated that MFM-yoghurt required 1.5 h longer than UPM-yoghurt to reach a pH of 4.5 at the end of fermentation, primarily owing to differences in Streptococcus thermophilus growth and lactoferrin (LF) content. UPM-yoghurt exhibited greater hardness, consistency, and water-holding capacity, resulting in a firmer gel texture. Conversely, MFM-yoghurt demonstrated lower viscosity but a smoother texture, possibly due to biologically active components. LF and lactoperoxidase (LPO) were absent in UPM-yoghurt, whereas MFM-yoghurt contained 106.00 mg/L of LF and 2986.25 U/L of LPO. Free amino acid analysis revealed lower levels of umami and bitter amino acids in MFM-yoghurt than those in UPM-yoghurt, while sweet amino acid levels were similar in both. The predominant volatile flavour compounds included aldehydes and ketones, with no significant differences observed in key compounds, such as 2-acetone, ethyl acetate, 3-hydroxy-2-butanone, and 2,3-butanedione, between the two yoghurts. However, notable variations were observed in 41 volatile flavour compounds between the samples, suggesting distinct flavour profiles. This study offers insights and directions for enhancing the nutritional quality of yoghurt.

Low-intensity pulsed electric fields pre-treatment on yogurt starter culture: Effects on fermentation time and quality attributes

Low-intensity pulsed electric fields (PEF) were applied to a starter culture mix (Streptococcus thermophilus, Lactobacillus bulgaricus, and partially skimmed milk) before the fermentation stage of natural yogurt. The impact of PEF processing conditions on yogurt fermentation time and quality characteristics was evaluated. PEF parameters were set based on a factorial experimental design; independent variables: electric field strength, pulse-frequency, and pulse-width, were explored, having fermentation time as a response. Most PEF treatments reduced fermentation time by 0.31–0.52 h compared to conventional yogurt processing (CY) (4.70 ± 0.23 h). The shortest time (4.18 ± 0.04 h) resulted from PEF pre-treatment with 8-μs monopolar pulses at 1 kV/cm and 150 Hz during 400 μs. The physicochemical and sensory characteristics of PEF-treated yogurt were similar to those of the CY immediately after processing and during refrigeration storage. Low-intensity PEF could be a promising alternative pre-treatment of yogurt production, reducing fermentation time while maintaining quality attributes of natural yogurt. Industrial relevanceConventional yogurt processing lasts around 4.5–6 h, representing high energy consumption and production costs. The application of pulsed electric fields (PEF) processing to the starter culture before yogurt fermentation represents a potential alternative to diminish production time by stimulating lactic acid bacteria and accelerating fermentation stage. This study demonstrated that low-intensity PEF (1–3 kV/ cm) reduced fermentation time by 0.31–0.52 h without compromising yogurt's quality properties, including physicochemical characteristics and sensory attributes. Obtained results suggest that this technology allows more efficient and sustainable yogurt production methods, positively impacting industry and consumers.

Functional yogurt: An approach to enhance yogurt quality with peanut polyphenols

This study aimed to investigate the impact of adding peanut polyphenols on the microbiological, physiochemical, and nutritional properties of yogurt. Polyphenols were extracted from peanuts and incorporated in yogurts formulations at 0.5%, 1.0% and 1.5%. The total phenolic content of yogurt with 1.5% peanut extract was greater (89.59 ± 0.0328 mg GAE/100 mL) than others. Addition of peanut polyphenols resulted in significant (p ≤ 0.05) increases in protein, fat, ash, and total solids content. Moreover, polyphenol supplementation significantly (p ≤ 0.05) influenced titrable acidity and water holding capacity. Titrable acidity increased over storage periods and water holding capacity improved with polyphenol addition. Gross energy was higher in yogurt with 1.5% fortification (85.5 ± 0.0145 Kcal/100 g) than in other formulated yogurts. Fortification significantly improved the total viable counts and total lactobacillus counts while total coliform count was undetectable. Sensory analysis indicated that yogurt fortified with 1.0% peanut polyphenols was preferred, considering all evaluated organoleptic parameters. These findings provide insights into optimizing yogurt fortification with peanut polyphenols to enhance its physicochemical and nutritional values.

Physicochemical, microbiological and sensory characterization of yogurt fermented by Weissella confusa SW1 and traditional starters

Starter cultures play important roles in the quality and functional activity of yogurt. In this study, a novel strain Weissella confusa SW1 was isolated from naturally fermented milk. The potential application of this strain in yogurt preparation was investigated and the unique qualities it conferred on yogurt was characterized. W. confusa SW1 could efficiently metabolize lactose and galactose, and the whole-genome sequencing showed that it has a complete Leloir metabolic pathway. Besides, W. confusa SW1 had strong antioxidant capacity, and could significantly promote the growth of Streptococcus thermophilus. Subsequently, W. confusa SW1 was co-cultured with traditional starters (Lb. bulgaricus and S. thermophilus) to prepare yogurt. The results showed that the scavenging rates of DPPH and ABTS radicals of W. confusa SW1 fermented yogurt increased from 79.51% to 85.19% and 80.14%–85.47%, respectively. Meanwhile, the viable bacterial counts of Lb. bulgaricus and S. thermophilus were increased in yogurt when co-cultured with W. confusa SW1. Furthermore, the addition of W. confusa SW1 reduced the curd time and improved the water holding capacity of yogurt. Thus, this study laid a theoretical foundation for the development of functional yogurt with the application of W. confusa SW1.

Protein of yak milk residue: Structure, functionality, and the effects on the quality of non-fat yogurt

The purpose of this study was to compare the structural and functional of protein from yak milk residue, which collected from different elevations (MRP1 and MRP2) in Tibet, as well as their potential for enhancing the quality of non-fat yogurt. The results showed that MRP1 exhibited higher levels of β-sheet, turbidity, particle size, and gel properties. MRP2 had better flexibility, emulsification, foaming, water/oil absorption capacity. The addition of MRP1 (3%) could improve texture and sensory properties of yogurt. Although MRP2 yogurt had higher hardness, gumminess, chewiness and water holding capacity, poor mouthfeel. Rheological test showed that MRPs yogurt exhibited typical gel-like and shear-thinning behavior. Moreover, the fortification of non-fat yogurts with MRP1 brought the formation of larger protein clusters with a more tightly knit network of smaller pores. These results indicate that MRP1 can be used as a fat substitute to improve the quality of non-fat yogurt.

Strategies to Improve the Quality of Goat Yogurt: Whey Protein Supplementation and Milk Pre-Treatment with High Shear Dispersion Assisted by Ultrasound

This work investigated the fermentation kinetics and characteristics of goat yogurt supplemented with bovine whey protein isolate (WPI) (0%, 2.5% and 5.0%) subjected to high shear dispersion (HSD) assisted by ultrasound (US). Protein supplementation and the physical processes increased the electronegativity of the zeta potential (≤60%), whereas particle size reduction was observed only with physical processes (≤42%). The addition of 2.5% WPI reduced yogurt fermentation time by 30 min. After 24 h of storage at 7 °C, lactic acid bacteria counts did not differ between samples (≥8 log CFU/mL), and the supplementation was sufficient to increase the apparent viscosity (≤5.65 times) and water-holding capacity (WHC) of the yogurt (≤35% increase). However, supplementation combined with physical processes promoted greater improvements in these parameters (6.41 times in apparent viscosity and 48% in WHC) (p < 0.05), as confirmed by the denser and better-organized protein clusters observed in microscopic evaluation. Thus, both approaches proved to be promising alternatives to improve goat yogurt quality. Therefore, the decision to adopt these strategies, either independently or in combination, should consider cost implications, the product quality, and market demand.

RETRACTION: Effect of adding Aloe vera jell on the quality and sensory properties of yogurt.

[This retracts the article DOI: 10.1002/fsn3.2017.].

Effects of rice wine on the quality and flavor characteristics of yogurt

Rice wine, a traditional Chinese fermented beverage, possesses both nutritional value and unique flavor. It is anticipated to enhance the nutritional potential and flavor of yogurt. This study aimed to assess the physicochemical, antioxidant, and sensory qualities of yogurt supplemented with varying concentrations of rice wine (0%, 5%, and 20%, v/v). The results revealed alterations in acidity, water-holding capacity (WHC), total sugar, texture characteristics, and rheological properties upon the addition of rice wine. Compared to the control group, yogurt supplemented with 5% and 20% rice wine showed higher total phenol content (TPC) and increased DPPH• clearance activity. Moreover, changes were observed in the hardness, adhesiveness, and gumminess of the experimental group. The addition of 5% YSRW resulted in an increased G′ and decreased G″ compared to the control group, which indicated that rice wine could increase the gel strength of yogurt. The variety and content of flavor substances in YSRW also increased, implying that rice wine might improve the sensory acceptance of yogurt. These findings suggested that rice wine can serve as a natural additive to enhance the flavor and taste of yogurt, which made it a promising ingredient for developing functional yogurt with desirable physiological, nutritional, antioxidant, and sensory qualities.

Brown rice protein–dietary fibre conjugate improves bioaccessibility of minerals via modifying gelling structure of yoghurt

SummaryThe present study aims to provide an overview of the impact of brown rice protein (BRP) conjugated with microcrystalline cellulose via the Maillard reaction on characteristic features of yoghurt and the bioaccessibility of essential minerals in this dairy product. The confirmation of conjugation was conducted using FTIR spectroscopy. Adding BRP or Maillard conjugate (MC) proved beneficial in enhancing the water‐holding capacity and decreasing the syneresis of samples. Additionally, yoghurt (MCY) containing the Maillard conjugate demonstrated superior performance in these properties. A lower number of pores and a stronger gel network (structural integrity) were identified in MCY compared to the other samples (BRPY: yoghurt containing BRP and PY: plain yoghurt). On the other hand, in general, supplementation of BRP and MC led to slight alteration in the concentration of aroma compounds. Similarly, the impact of BRP and MC on changes in the molecular weight distribution of proteins during in vitro gastrointestinal digestion was negligible. Bioaccessibility values of Ca and Mg in PY were 53.72% and 10.72%, respectively. The improvement in these values was observed in BRPY (Ca: 57.33% and Mg: 15.60%). Moreover, adding MC to yoghurt led to a tighter interface structure (indicating rigid gel), which allowed more minerals to bind, increasing mineral bioaccessibility (Ca: 64.40% and Mg: 31.14%). A higher general acceptability in sensory evaluation was scored for PY followed by MCY and BRPY. Ultimately, the positive effect of ingredients (especially MC) on yoghurt quality was obvious.

Anti-osteoporosis effect of Mori Follum- Portulaca oleracea L.- Lycium barbarum L. extract based on network pharmacology and experimental validation and its utilization in functional yogurt

In China, Mori Follum, Portulaca oleracea L., and Lycium barbarum L. are traditional Chinese medicine and food used in treating osteoporosis. However, the active compounds, targets, and specific molecular mechanisms of the triangular herb composed of "Mori Follum, Portulaca oleracea L., and Lycium barbarum L." (MPL) have not been fully elucidated. In this study, the chemical components of MPL were first identified by LC-MS. Next, network pharmacology was used to identify the core targets and key pathways of MPL in anti-osteoporosis. And molecular docking simulations were conducted. The prediction results were validated by in vitro experiments using MC3T3-E1 cells. This study screened 22 active compounds from MPL, with a total of 59 targets involved in the treatment of osteoporosis. IL6, TNF, PTGS2, AKT1, ESR1, TP53, HIF1A, PPARG, PRKACA are core targets, and PI3K/AKT is a key pathway. Molecular docking showed that Wongnin, Hirsutine, and Cryptotanshinone strongly bind with AKT1 and ESR1. MPL could promoted MC3T3-E1 cell proliferation and differentiation and regulated the expression of key proteins in the PI3K/AKT/Runx2 signaling pathway. Further, MPL was used as a prebiotic-assisted fermentation to obtain functional yogurt with osteogenic activity. Moreover, MPL1 could improve the fermentation rate, exhibiting better ideal physicochemical properties and sensory quality of yogurt. This study provides a foundation for developing MPL as an anti-osteoporosis functional food.