Antioxidant Activity Of Yogurt Research Articles

Development of spray-dried yogurt with addition of cinnamon extract as a functional drink

The addition of cinnamon extract was done to improve the functional properties of yogurt. The limiting factor of yogurt is the difficulty of maintaining the quality in the distribution process. Spray drying technology is suitable for maintaining the quality of yogurt during distribution. This study aimed to evaluate the characteristics and antioxidant activity of yogurt with the addition of cinnamon extract before and after spray drying process. Research was conducted using factorial pattern of complete randomize design 2×3 (levels of extract and type of yogurt). The samples were evaluated for its pH, water activity, viscosity, titratable acidity, total lactic acid bacteria, antioxidant activity by DPPH inhibition, total phenolic compound (TPC), nutrient content and sensory properties. Yogurt powder obtained from spray drying process were analyzed for its visual appearance using scanning electron microscopy. Results showed that pH, viscosity, titratable acidity, viable lactic acid bacteria, protein and ash content were significantly affected by spray drying process, while moisture content and TPC were significantly affected by both spray drying and type of yogurt. Overall, after spray drying process, rehydrated cinnamon-yogurt still had antioxidant capacity and quality that met the requirement according to Indonesian Standard and CODEX.

Effect of whey protein isolate addition on set-type camel milk yogurt: Rheological properties and biological activities of the bioaccessible fraction

The manufacture of camel milk (CM) yogurt has been associated with several challenges, such as the weak structure and watery texture, thereby decreasing its acceptability. Therefore, this study aimed to investigate the effect of whey protein isolate (WPI) addition on the health-promoting benefits, texture profile, and rheological properties of CM yogurt after 1 and 15 d of storage. Yogurt was prepared from CM supplemented with 0, 3, and 5% of WPI and compared with bovine milk yogurt. The results show that the water holding capacity was affected by WPI addition representing 31.3%, 56.8%, 64.7%, and 45.1% for yogurt from CM containing 0, 3 or 5% WPI, and bovine milk yogurt, respectively, after 15 d. The addition of WPI increased yogurt hardness, adhesiveness, and decreased the resilience. CM yogurt without WPI showed lower apparent viscosity, storage modulus, and loss modulus values compared with other samples. The supplementation of CM with WPI improved the rheological properties of the obtained yogurt. Furthermore, the antioxidant activities of yogurt before and after in vitro digestion varied among yogurt treatments, which significantly increased after digestion except the superoxide anion scavenging and lipid oxidation inhibition. After in vitro digestion at d 1, the superoxide anion scavenging of the 4 yogurt treatments respectively decreased from 83.7%, 83.0%, 79.1%, and 87.4% to 36.7%, 38.3%, 44.6%, and 41.3%. The inhibition of α-amylase and α-glucosidase, angiotensin-converting enzyme inhibition, cholesterol removal, and degree of hydrolysis exhibited different values before and after in vitro digestion.

EPS-Producing Lactobacillus plantarum MC5 as a Compound Starter Improves Rheology, Texture, and Antioxidant Activity of Yogurt during Storage

This study evaluated the effects of probiotic Lactobacillus plantarum MC5 on the quality, antioxidant activity, and storage stability of yogurt, to determine its possible application as a starter in milk fermentation. Four groups of yogurt were made with different proportions of probiotic L. plantarum MC5 and commercial starters. The yogurt samples’ rheological properties, texture properties, antioxidant activity, storage stability, and exopolysaccharides (EPS) content during storage were determined. The results showed that 2:1 and 1:1 yogurt samples (supplemented with L. plantarum MC5) attained the highest EPS content (982.42 mg/L and 751.71 mg/L) during storage. The apparent viscosity, consistency, cohesiveness, and water holding capacity (WHC) of yogurt samples supplemented with L. plantarum MC5 were significantly higher than those of the control group (p < 0.05). Further evaluation of antioxidant activity revealed that yogurt samples containing MC5 starter significantly increased in DPPH, ABTS, OH, and ferric iron-reducing power. The study also found that adding MC5 can promote the growth of Streptococcus thermophilus. Therefore, yogurt containing L. plantarum MC5 had favorable rheological properties, texture, and health effects. The probiotic MC5 usage in milk fermentation showed adequate potential for industrial application.

OPTIMIZATION OF JAMBLANG (Syzygium Cumini (L.) Skeels) FRUIT EXTRACT LEVELS IN YOGHURT FORMULATION AS ANTIOXIDANT

&#x0D; The reactivity of oxidant compounds that exceed the limits of antioxidant protection ability can cause chain reactions which cause interference with the system. Prevention is needed to neutralize the oxidants, so that exogenous antioxidants are needed. One example is the jamblang fruit (Syzygium cumini (L)) which has high antioxidant activity due to its natural anthocyanin. The purpose of this study was to determine the optimal form of yogurt with the addition of jamblang fruit extract with a concentration of 0%, 5%, 7.5% and 10% and the quality of SNI. Tests carried out include physical, chemical and microbiological tests, namely sensory, acid content, total protein, fat content, and a number of bacterial starters, as well as safety tests with storage at 4° C then 0, to 7, 14th, 21st and 28th day. Data analysis using MANOVA. The results of the effect of the product showed that the fruit of yogurt with 10% extract level provided good stability during storage. Decreased antioxidant levels on day 7 to day 28. Antioxidant activity is more stable than antioxidant jamblang fruit extract. The antioxidant activity of yogurt with 5% jamblang fruit extract; 7.5% and 10% on day 0% % inhibition value of 57.48%; 62.06%; and 73.01%.&#x0D; &#x0D; &#x0D; &#x0D; &#x0D; &#x0D; &#x0D; &#x0D; &#x0D; &#x0D;

The addition of Andean lupin (Lupinus mutabilis) protein concentrate enhances the nutritive value and the antioxidant activity of yoghurt

Introduction: Andean lupin seeds are under-exploited sources of nutrients and bioactive compounds. Materials and methods: seeds were debittered to remove toxic alkaloids, partially defatted with 70% ethanol, dried at 60°C and milled. The defatted flour was suspended in water adjusted at pH 7 with 1N NaOH. The protein extract was filtered and spray-dried. Enriched yoghurts were obtained with the addition of lupin protein concentrate at 0.5, 1 and 1.5%. The chemical and fatty acid composition, the contents of polyphenols and flavonoids as well as the antioxidant activity were determined. The microbial quality and physicochemical properties (pH values, lactic acid content and percentage of syneresis) were evaluated in yoghurts during 28 days of storage. Results: Andean lupin concentrate showed high protein and carbohydrate contents (69% and 20%), unsaturated fatty acids (77%) mainly oleic, linoleic and α-linolenic acids as well as low atherogenic and thrombogenic indexes (0.07 and 0.44). The addition of the lupin protein concentrate at 1.5% into yoghurts increased the protein content. Enriched yoghurts showed higher unsaturated fatty acids, total polyphenol and flavonoid contents as well as lower atherogenic and thrombogenic indexes compared to the control. The lupin protein concentrate increased the ABTS radical scavenging activity, the ferric reducing power and the total antioxidant activity in yoghurts. Enriched and control yoghurts showed similar lactic acid bacterial counts. The counts for total and thermotolerant coliforms were under three MPN/mL and yeast and molds under 10 CFU/ mL. The pH values in enriched products were higher at days 1 and 7 of storage (4.82 and 4.95) compared to the control sample (4.72 and 4.85). The lactic acid content increased in all formulations at day 21. Enriched yoghurts showed lower syneresis than the control. Conclusions: Yoghurts enriched with lupin protein concentrate could represent nutritive and functional alternatives to prevent chronic diseases when consuming in a healthy diet.

The Influence of Hazelnut Skin Addition on Quality Properties and Antioxidant Activity of Functional Yogurt.

There is an increasing interest in applying fruit-processing wastes as functional food ingredients. Hazelnut skin, an interesting and innovative ingredient has recently been evaluated as one of the richest edible sources of polyphenolic compounds. This study aimed to evaluate the use of hazelnut skin as a functional additive in yogurt and to determine the effect of various percentages (2%, 3%, and 4%) of hazelnut skin on the physicochemical, microbiological, rheological, biochemical, and sensorial properties of yogurt. The results showed that the addition of hazelnut skin significantly increased total solids from 16.5% to 17.7% and fat content from 3.45% to 4.60% and decreased titratable acidity by up to 36%. The enrichment with hazelnut skin also improved the viability of yogurt bacteria, water holding capacity (WHC), and antioxidant activity of yogurts. Better results for WHC and antioxidant values were found in yogurt enriched with 4% hazelnut skin. Total phenolic content and Fe2+ chelating activity of yogurts increased with the increasing hazelnut skin ratio. However, yogurts with hazelnut skin had low instrumental texture parameters and apparent viscosity values. On the other hand, acceptable sensorial properties similar to control yogurts increase the consumption potential of yogurts enriched with hazelnut skin.

Effects of thermally treated mulberry leaves on the quality, properties, and antioxidant activities of yogurt

Effects of thermally treated mulberry leaves on the quality, properties, and antioxidant activities of yogurt

Inhibition of Advanced Glycation End Products in Yogurt by Lotus Seedpod Oligomeric Procyanidin.

The basic ingredients of yogurt include lactose and protein. Yogurt undergoes the Maillard reaction easily, producing many advanced glycation end products (AGEs) that cause some chronic diseases. Lotus seedpod oligomeric procyanidin (LSOPC) have demonstrated a strong inhibitory effect on AGE formation in simulated models; however, the inhibition of procyanidin on AGE formation and the subsequent effects on yogurt quality remains unknown. Our study demonstrated that LSOPC had a good inhibitory effect on the formation of fluorescent AGEs and Nε-carboxymethyl lysine (P < 0.05). The inhibitory capacity on AGEs and antioxidant activity of yogurt were positively correlated with the concentration of LSOPC. The effect of LSOPC on the physicochemical properties of yogurt was also evaluated. Bound water content, viscosity, and flavor of yogurt were significantly increased after LSOPC addition (P < 0.05). Therefore, LSOPC may lead to significant benefits for controlling AGE formation and improving the quality of yogurt.

Effect of Supercritical Extract from Black Poplar and Basket Willow on the Quality of Natural and Probiotic Drinkable Yogurt.

Simple SummaryFermented milk products should be an important component of the human diet due to their high nutritional value and easy digestibility. In order to enhance the nutritional value of yogurts, additives in the form of plant-based raw materials are often used. Phytoextracts are a mixture of biologically active compounds that can have beneficial effects on the human body and influence both the manufacturing process and the quality of food products. The incorporation of extracts from the basket willow (Salix viminalis) into natural and probiotic yogurts reduced the fermentation time and increased their antioxidant activity. Sensory evaluation of the appearance and texture of yogurts enriched with extracts showed no significant differences compared to natural yogurts. The addition of plant extracts may enable the standardisation of yogurt quality and increase its biological activity.Yogurt is a fermented milk drink produced by Streptococcus thermophilus, Lactobacillus delbrüeckii ssp. bulgaricus, or Lactobacillus rhamnosus, which can be enriched with polyphenolic compounds to enhance its antioxidant properties. Supercritical (scCO2/H2O) extracts obtained from the mixture of bark and wood of black poplar (Populus nigra) and basket willow (Salix viminalis) are the source of bioactive compounds. The aim of the study was to assess the effect of supercritical extracts from the P. nigra and S. viminalis on the fermentation, quality, and bioactive properties of drinkable natural and probiotic yogurts. The incorporation of scCO2/H2O extracts at a dose of 0.01% (w/v) into milk for the production of natural and probiotic yogurts increases their functional properties by enhancing the antioxidant activity without causing negative effects on the physicochemical and organoleptic properties of products. The antioxidant activity of yogurt with scCO2/H2O extract from P. nigra and S. viminalis was higher than control yogurts by 1.3–13.2% and 4.4–37.5%, respectively. The addition of a supercritical S. viminalis extract reduced the time of natural and probiotic yogurt fermentation. Natural and probiotic yogurt with scCO2/H2O extracts added was characterised by a bacterial population size of over 7 log cfu/g, and the microflora was active throughout the cold storage period. FTIR analysis confirmed the presence of scCO2/H2O extracts from P. nigra or S. viminalis in both types of yogurt. A secondary structure analysis confirmed interactions between compounds of scCO2/H2O extract from P. nigra and S. viminalis extract with milk proteins. These interactions affect the compounds’ structural and functional properties by changing, e.g., their digestibility and antioxidant properties.

Microbial, physiochemical and functional properties of probiotic yogurt containing Lactobacillus acidophilus and Bifidobacterium bifidum enriched by green tea aqueous extract.

In this study, the effect of aqueous extract of green tea on the viability of probiotic bacteria including Lactobacillus acidophilus and Bifidobacterium bifidum and the sensory and physicochemical and functional properties of synbiotic yogurt was investigated during 4 weeks of storage. L. acidophilus and B. bifidum counts did not significantly change in yogurt containing 0.5% and 1% of the extract during storage. Also, the addition of the extract to yogurt highly increased the phenolic compounds, since the amount of phenolic compounds in yogurt containing 0.5% and 1% extract was 660 and 1,123 mg gallic acid/kg, respectively. In addition, a significant increase in the antioxidant activity of yogurt containing green tea extract was observed in comparison with the control. The amount of antioxidant activity increased during 4 weeks of storage, which reached to 4,193 and 7,337 mg BHT eq./kg in probiotic yogurt containing 0.5% and 1% extract, respectively. The acidity increased during 4 weeks of storage, while the pH decreased. Addition of the extract significantly increased the acidity of probiotic yogurt compared with the control (p < .05). In addition, in all studied groups, an increase in syneresis was observed during the study, and the syneresis was greater in yogurt containing aqueous extract of green tea, compared with the control group. Although adding the green tea extract to probiotic yogurt impaired taste, texture, and appearance compared with the plain yogurt, the overall acceptability of these samples was yet above the acceptable level. In conclusion, the results of the study showed that the addition of aqueous extract of green tea increased the antioxidant properties and the amount of phenolic compounds in yogurt, while the viability of probiotic bacteria was not changed. Therefore, the simultaneous use of green tea extract and probiotics in yogurt is recommended as an effective functional food formulation.

Bacterial Inhibition and Antioxidant Activity of Probiotic Yoghurt Developed Using Microbial Isolates from Soymilk

The aim of this study was to investigate the bacterial inhibition and antioxidant activities of probiotic yoghurts developed using microbial isolates from Soymilk. Bacterial inhibitory activity of yoghurt was evaluated against Staphyloccocus aureus, Bacillus subtillis, Escherichia coli and Pseudomonas flourescens by using the disk diffusion method. The yoghurt showed some inhibitory activities against all the organisms tested. Antioxidant activity of yoghurt was measured using three different methods- Diphenyl-1-picryl hydroxyl (DPPH) radical scavenging activity, lipid peroxidase assay and hydroxyl radical scavenging activity against Butylated hydroxyanisole (BHA) as standard. The results showed that probiotic yoghurt exhibits relative high antioxidant activities as compare to BHA. However, by implications this study suggests that probiotic yoghurt has some inhibitory activities against all the bacteria tested, also can be consider among the most promising functional foods for their antioxidant activity and ability to prevent oxidative damage and attendant ageing.

Antioxidant Activities and Profile of Amino Acid of Yoghurt from Beef Milk Fermentation with Dadih Starter

Dadih is naturally fermented buffalo milk in bamboo tubes and known to have antioxidant, antibacterial, and antihypertensive activity. Lactic acid bacteria in dadih can use as a starter to produce yogurt. The study aimed to produce yogurt of cow's milk with dadih as a starter, to determine the antioxidant activity and amino acid composition. Dadih is added with concentration variation of 2.5; 5; 7.5 and 10% (v/v) and it fermented for 48 hours at room temperature. Lactic acid bacteria cell counts of dadih were calculated by the total plate count method. Yogurt was tested by organoleptics with 33 panelists and proximate analysis water, ash, fat and protein contens based on the Association of Official Analytical Chemist (AOAC) in 2005. Antioxidant activities of yogurt were tested by DPPH method (1,1-diphenyl-2-picrylhydrazyl). Amino acid composition of yogurt was analyzed using ultra performance liquid chromatography (UPLC). The research result of amount of LAB on dadih are 1.01 x 1011 CFU/mL, has fulfilled the requirements of SNI 2981: 2009. Yogurt produced with the addition of dadih by 10% (v/v) is most accepted by panelists. The highest antioxidant activity was obtained by yogurt with 2.5% addition of dadih with IC50 value of 78.28 ppm. Yogurt almost contain all essential and non-essensial amino acids including tyrosine and phenylalanine as the antioxidants. Measurement of water, ash, protein and fat content in the sample meets the requirements of SNI 2981: 2009.

Antioxidant Activities and Profile of Amino Acid of Yoghurt from Beef Milk Fermentation with Dadih Starter

Dadih is naturally fermented buffalo milk in bamboo tubes and known to have antioxidant, antibacterial, and antihypertensive activity. Lactic acid bacteria in dadih can use as a starter to produce yogurt. The study aimed to produce yogurt of cow's milk with dadih as a starter, to determine the antioxidant activity and amino acid composition. Dadih is added with concentration variation of 2.5; 5; 7.5 and 10% (v/v) and it fermented for 48 hours at room temperature. Lactic acid bacteria cell counts of dadih were calculated by the total plate count method. Yogurt was tested by organoleptics with 33 panelists and proximate analysis water, ash, fat and protein contens based on the Association of Official Analytical Chemist (AOAC) in 2005. Antioxidant activities of yogurt were tested by DPPH method (1,1-diphenyl-2-picrylhydrazyl). Amino acid composition of yogurt was analyzed using ultra performance liquid chromatography (UPLC). The research result of amount of LAB on dadih are 1.01 x 1011 CFU/mL, has fulfilled the requirements of SNI 2981: 2009. Yogurt produced with the addition of dadih by 10% (v/v) is most accepted by panelists. The highest antioxidant activity was obtained by yogurt with 2.5% addition of dadih with IC50 value of 78.28 ppm. Yogurt almost contain all essential and non-essensial amino acids including tyrosine and phenylalanine as the antioxidants. Measurement of water, ash, protein and fat content in the sample meets the requirements of SNI 2981: 2009.

Determination of antioxidant activity and total phenolic contents in yogurt added with black cumin (Nigella sativa L.) honey

Abstract This study aims to reveal the antioxidant activity and phenolic ingredients of yogurts added with black cumin (Nigella sativa L.) honey. Therefore, this study aimed to produce healthy food made with black cumin honey with increased total phenolic contents and antioxidant activity. The effect of varying degrees of black cumin honey addition (0, 2.5%, 5%, 10%, 15%) on the antioxidant activity and total phenolic contents of yogurt were examined for 28 days. The antioxidant activity was found between 14.33 and 17.41 mM TE. Total phenolic compounds were between 202.50 and 1415.00 mg GAE/kg. Some important differences were determined between yogurts with black cumin honey and the control with respect to phenolic contents during storage (p &lt; 0.05). The results of study reveal that the augmentation of fortification rate increased the total phenolic characteristic and antioxidant activity of yogurt with black cumin honey. Significantly, these outcomes indicate that yogurt with black cumin honey have a high level of polyphenols and could be consumed as bioactive composition.

Physicochemical properties of Ocimum sanctum enriched herbal fruit yoghurt

Fruit yoghurt with tulsi enhance the nutritional value and satisfy rising demands for healthy food products. Three different concentrations of TLE (0.5%, 1%, and 1.5%); and apple pulp (10%) were used for the formulation of herbal fruit yoghurt. The enriched milk (26.42–28.58 min) showed lower heat stability than that of control (29.80 min), however, sufficient to withstand sterilization treatment up to 1% TLE addition. Furthermore, physicochemical properties viz. pH, water holding capacity, acidity, moisture, water activity, setting time, and whey-off experiment were not affected significantly (p > .05) in comparison to control yoghurt. The tulsi addition significantly (p < .05) increased (from 32.43% to 45.47% inhibition) the antioxidant activity of yoghurt. The firmness of herbal fruit yoghurt was decreased than control yoghurt. Sensory scores were decreased with an increase in the concentration of TLE (88.75 to 85.14) in comparison to control (91.96), however, yoghurt was suitable for consumption up to 1% TLE. Practical applications Dahi, Tulsi, and fruit mix are considered as religious food and known as Panchamrite. Yoghurt is considered as western dahi in India, however, no such mixture is tried with yoghurt. Therefore, the feasibility of yoghurt with tulsi and apple was carried out, as yoghurt has higher health benefits even than tulsi. A good quality yoghurt was developed using tulsi and apple pulp, therefore, it will capture a huge place in the Indian market.

The effects of adding Hibiscus sabdariffa L. flowers marmalade on some quality properties, mineral content and antioxidant activities of yogurt.

In this study, the effect of Hibiscus sabdariffa L. flowers marmalade (HM) addition at different ratios (0%, 15%, 20%) was determined on the certain quality properties, total phenolic contents, antioxidant activity, mineral composition and heavy metal content of stirred-type yogurts (C, HM15, and HM20). The marmalade addition increased dry matter, ash, titratable acidity and viscosity whereas decreased pH, fat and protein values. HM addition significantly increased the antioxidant properties of yogurt samples. 2,2-Diphenylpicrylhydrazyl radical-scavenging activity, Copper (II) reducing antioxidant capacity and total phenolic content were found to be in the range of 5.92-26.73mg TE/100g, 4.88-15.03mg TE/100g, and 5.57-14.69mg GAE/100g, respectively. There were no statistically differences between control and HM-added groups in terms of lactic acid bacteria (LAB) counts, also in all samples the total LAB count was above 6 Log cfu/g during the storage. Fe, Mn, B, and Ba mineral values of samples with HM were higher than control sample. Cd, As, Hg and Li heavy metals were not detected in any of the samples, consequently results were within reliable limits reported by JECFA (Joint FAO/WHO Expert Committee on Food Additives) and Turkish Food Codex. As a result of the sensory evaluation, the samples containing 20% HM generally received higher scores than the samples containing 15% HM. Considering all the parameters, it was concluded that HM yogurts can be used as a different type in the functional yogurt industry due to its pleasant and characteristic taste.

Quality characteristic and antioxidant activity of yogurt containing olive leaf hot water extract

ABSTRACT The objective of this study was to determine the antioxidant and quality characteristics of yogurt containing olive leaf hot water extract (CON: 0, OLY1: 0.1, OLY2: 0.2, and OLY4: 0.4% (w/v)) stored at 4°С for 15 days. After storage, the lactic acid bacteria count showed no significant difference between yogurt samples either in the presence or absence of olive leaf extract (p > 0.05). The total phenolic content, DPPH radical scavenging activity, and reducing power increased upon increasing the content of the olive leaf hot water extract. Oleuropein was found to be the most abundant phenolic compounds present in olive leaf, and the oleuropein content in OLY4, as measured by HPLC, decreased gradually to 1.09, 1.00, and 0.96 g/L upon increasing the storage time; however, this reduction was not significant (p > 0.05). In sensory evaluations, OLY1 gave the highest score among the experimental groups. The results of this study thereby demonstrate that olive leaf hot water extract can be used to improve the antioxidant capacity and sensory characteristics of yogurt.

Physico-Chemical, antioxidant activities, textural, and sensory properties of yoghurt fortified with different states and rates of pomegranate seeds (Punica granatum L.).

This study examines the effects of incorporating fresh, frozen, osmodehydrated, and dried pomegranate seeds, at different concentrations (5, 10, and 20%) on the physicochemical, antioxidant, textural, and sensory properties of yoghurt. Antioxidant activity, pH, acidity, syneresis, and color of yoghurt were also evaluated during the storage (28 days) at 4°C. The principal component analysis (PCA) was performed to assess the correlations between different yoghurt formulation and their sensory attributes. Data showed that the addition of pomegranate seeds reduced pH and modified the chromatics coordinate (L*, a*, b*, C*, h°) and firmness of the yoghurt samples. In addition, acidity, °Brix, and syneresis increased compared to the control. Thanks to their high anthocyanin content, pomegranate seeds considerably improved the antioxidant activity essentially for yoghurt enriched with frozen seeds. In addition, the supplementation of 20% of frozen seeds into yoghurt was the most appreciated by panelists and improved the sensory properties in comparison to other formulation. According to PCA, taste and appearance were the main criteria for the overall acceptability of yoghurt. After 28 days of storage, the reddish color was reinforced; however, the antioxidant activity of yoghurts was reduced. Overall, it can be concluded that pomegranate seeds can be used as a natural ingredient to develop a novel yoghurt with high nutritional properties.

The quality characteristics, antioxidant activity, and sensory evaluation of reduced-fat yogurt and nonfat yogurt supplemented with basil seed gum as a fat substitute

This study investigated the use of basil seed gum (BSG) as a fat substitute on the physicochemical properties and antioxidant activities of yogurt. A 0.5 and 1% BSG solution was supplemented to reduced-fat and nonfat yogurts, and their physicochemical properties, quality properties, antioxidant activity, and sensory evaluation were compared with each control group. We prepared 3 yogurts as controls and 4 yogurt samples containing BSG as follows: FFY (yogurt made from full-fat milk: a control group), LFY (yogurt made from reduced-fat milk: a control group), SY (yogurt made from nonfat milk: a control group), LFY 0.5% (0.5% BSG added to reduced-fat yogurt), LFY 1.0% (1.0% BSG added to reduced-fat yogurt), SY 0.5% (0.5% BSG added to nonfat yogurt), and SY 1.0% (1.0% BSG added to nonfat yogurt). The pH of LFY 0.5% and LFY 1.0% was decreased compared with LFY control, whereas pH of SY 0.5% and SY 1.0% had no significant difference. The titratable acidity showed no significant increase. The viscosity was the highest in FFY among the control groups and increased with the concentration of BSG in the SY group. The L-value (brightness) and b-value (yellowness) were the highest in FFY at 85.05 among the control groups. The L-value and b-value of LFY 0.5% and SY 0.5% showed higher values than LFY 1% and SY 1%. The a-value (redness) was the highest in SY 0.5% at -2.36, and ΔE (total color difference) was the highest in SY 1% at 7.33. The moisture content of SY was the highest among the control groups and addition of 1% BSG to SY was highest among the BSG-added group. Total contents of phenol and flavonoid slightly increased as the concentration of BSG increased (increase in the contents of phenol and flavonoid). The results of ferric reducing antioxidant power were similar to the findings of phenol and flavonoid content (an increase as the concentration of BSG increased). The overall acceptability of sensory characteristics was improved in all groups of samples when BSG 1% concentration increased. Application of BSG for the production of nonfat yogurt can enhance physicochemical properties, antioxidant activity, and sensory characteristics of reduced-fat and nonfat yogurt. Addition of BSG to reduced-fat and nonfat yogurt can improve their physical and antioxidant properties to the level of FFY.

Effects of Lotus (Nelumbo nucifera) Leaf on Quality and Antioxidant Activity of Yogurt during Refrigerated Storage.

The supplementation with natural ingredients that are rich in polyphenols could improve the quality and functionality of yogurt. Lotus leaf (LL) are abundant in phenolic compounds. We aimed to investigate the effects of LL powder on the quality properties, total phenolic content (TPC), and antioxidant activity of yogurt. Yogurt was supplemented with four different concentrations (0%, 0.2%, 0.5%, and 1%) of LL powder and evaluated for 14 d refrigerated storage. During storage, the titratable acidity (TA) of all LL yogurt groups was higher than that of the control (p<0.05). The L* and a* values decreased by LL addition to the yogurts, while the b* values increased. All LL yogurt groups indicated better viscosity than that of control, and among them, 0.2% LL yogurts had the highest viscosity without significant decrease until the end of the storage duration. The addition of LL into yogurt enhanced the water-holding capacity (WHC) by at least 1.5-fold than that of control for the entire storage duration. The TPC of yogurts gradually increased with the addition of LL (p<0.05) and continued to increase during storage; the 1% LL yogurt at 14 d showed the highest value of 61.94±1.68 μg GAE/g. The DPPH (2,2-diphenyl-1-picrylhydrazyl) radical scavenging activity and reducing power of the yogurts were also significantly enhanced with increasing LL concentrations (p<0.05). These results suggest that lotus leaf may be useful as a natural ingredient for improving the quality and antioxidant activity of yogurt.