Yogurt Products Research Articles

Quality evaluation and microbial enumeration of plant based probiotic yoghurt from powdered milk and tiger nut milk

Some commercial yoghurt manufacturers have promoted the usage of artificial thickening and binding agents in the production of yoghurt. These substances, most of which are chemically synthesized could be dangerous. The purpose of this research is to assess the physicochemical characteristics of yogurt made from full cream milk, skimmed milk, and tiger nut milk. It also aimed to estimate the total aerobic plate count, total coliform count, and total mold count of the products for microbiological analyses. The powdered milk samples were reconstituted into liquid and the sorted-clean tiger nut was blended in order to extract the milk. Tiger nut milk proportion of 20 to 30 % was incorporated into the liquid milk before fermentation. The harvested yoghurt was assayed for sensory, physicochemical and microbial analyses. The result obtained showed a level of significant difference (p < 0.05). Among the samples produced, sample G has the least acceptable value 5.00 while sample C had the highest acceptable value 7.05 across the sensory scores. The values obtained from the physicochemical analysis showed that pH value ranged from 3.67 to 4.97. For TDS and titratable acidity (TA), the values ranged from 4.53 to 6.72 x 102 ppm and 0.62 to 0.87 respectively. None of the yoghurt samples had coliform growth on the medium after the incubation period while total viable count ranged from 78.67 to 227.33 cfu/ml and total mould count ranged from 16.67 to 56.67 sfu/ml at a dilution factor of 102. Tiger nut milk can be used in the production of yoghurt as a possible substitute because of its nutritional content and health advantages. Therefore, it is imperative to assert that the use of tiger nut milk in the manufacturing of yoghurt will improve the quality of yoghurt and ultimately result in a desired product.

Application of optimized Streptococcus thermophilus and Lactobacillus bulgaricus on coconut milk in the production of niyoghurt

This research aimed to optimize the growth of commercial yogurt starter cultures (Streptococcus thermophilus and Lactobacillus bulgaricus) on coconut milk before they were applied in the production of coconut yogurt, which is known as niyogurt or cocogurt. The research consists of three steps. Firstly, both microbes were grown on 100% cow’s milk and were analyzed for pH and total lactic acid bacteria (LAB) to examine the length of fermentation time. Secondly, both microbes were gradually grown on cow’s milk and coconut milk media, with samples ranging in combinations of the two kinds of milk from 100% milk to 100% coconut milk. Finally, the optimized starter cultures were then applied to niyogurt production. The results showed that the pH of the starter cultures obtained in 100% milk after 48 hours of fermentation was 4.41±0.04 for Streptococcus thermophilus and 4.44±0.03 for Lactobacillus bulgaricus. Meanwhile, the total lactic acid bacteria counts were 8.62±3.03 log cfu/ml for Streptococcus thermophilus and 9.55±2.22 log cfu/ml for Lactobacillus bulgaricus. These results showed that both commercial starter cultures need long periods to reach the targeted pH and total lactic acid bacteria (LAB) suggesting that enrichment was needed before commercial starter cultures were used. Furthermore, after analyzing six samples of growth on different ratios of milk and coconut milk, it was seen that both starters could grow optimally on 100% coconut milk. The total LAB after 24 hours of fermentation was 11.07 log cfu/ml with pH 4.05. Based on chemical and microbiological analyses, the characteristics of niyogurt have met Indonesia’s Standard for food consumption (SNI 2981:2009). The niyogurt consisted of 3.15% protein content, 8.3% fat content, 0.83% total acid, 0.76% mineral content, and 11.48 log cfu/ml total LAB.

Physicochemical, Rheological, and Sensory Characteristics of Yogurt Fermented by Lactic Acid Bacteria with Probiotic Potential and Bioprotective Properties.

The applicability of two lactic acid bacterial strains with probiotic potential and bioprotective properties as additions in the starter culture in yogurt fermentation was examined. The studied strains, Lactobacillus delbrueckii subsp. bulgaricus KZM 2-11-3 and Lactiplantibacillus plantarum KC 5-12, inhibited the growth of Kluyveromyces lactis, Kluyveromyces marxianus, and Saccharomyces cerevisiae. The strain L. delbrueckii subsp. bulgaricus KZM 2-11-3 directly inhibited Escherichia coli. The important characteristics for the quality of the yogurt product, such as physicochemical parameters during fermentation and storage, rheological characteristics, and sensory changes during the storage of samples were determined. The yogurt samples with the strains did not differ in most parameters from the control yogurt with the commercial starter. The added strains showed stable viability in the yogurt samples during storage. The yogurt sample with L. delbrueckii subsp. bulgaricus KZM 2-11-3 and the sample with both strains based on the total evaluation were very similar to the control yogurt with the commercial starter. Using these strains as probiotic supplements to enrich the starter cultures in yogurt production will contribute to developing new products with benefits to human health.

Effect of Hydrolyzed Lima Protein (Phaseolus Lunatus) on The Quality of Yogurt Products

Effect of Hydrolyzed Lima Protein (Phaseolus Lunatus) on The Quality of Yogurt Products

Cholesterol-lowering activity by lactic acid bacteria isolated from yogurt from Boyolali, Indonesia

Abstract. Nurcahyani I, Susilowati A, Pangastuti A. 2023. Cholesterol-lowering activity by lactic acid bacteria isolated from yogurt from Boyolali, Indonesia. Asian J Nat Prod Biochem 21: 34-45. Hypercholesterolemia is considered a risk factor for cardiovascular disease, as it is characterized by increased cholesterol levels in the bloodstream that exceed the established normal range. At present, cardiovascular disease stands as the foremost cause of mortality worldwide, with a global death toll of 17.7 million. The employment of Lactic Acid Bacteria as a probiotic has the potential to reduce cholesterol levels via the enzymatic of Bile Salt Hydrolase (BSH), which facilitates the deconjugation of bile salts, as well as its capacity to assimilate cholesterol directly. The consumption of fermented dairy products that have undergone appropriate bacterial fermentation has been found to potentially contribute to a reduction in blood cholesterol. The region of Boyolali in Indonesia is known for its yogurt production; regularly consuming probiotic products has been suggested as a dietary approach to promoting long-term hypocholesterolemia effects. The objective of this research was to isolate and evaluate the efficacy of Lactic Acid Bacteria (LAB) in reducing cholesterol levels, and to identify the specific isolates derived from yogurt originating from Boyolali. The activity of the BSH enzyme was evaluated through qualitative testing by observing precipitation zones on the growth media. A quantitative assessment was also conducted using the UV-vis spectrophotometer method at ?570 nm. LAB isolates' activity in bile salt deconjugation and cholesterol assimilation was also measured using the UV-vis spectrophotometer method at ?660 nm and ?550 nm, respectively. The bacterial identification process was conducted through the examination of both macroscopic and microscopic morphology. The study employed a One-way Analysis of Variance (ANOVA) to compare the release of amino acids (specifically glycine and taurine), the release of free cholic acid, and the disparity in cholesterol levels between media that were inoculated with LAB and those that were not. The BSH enzyme activity was observed to be 1.11-3.82 U/mL for sodium glycocholate substrate and 0.85-3.13 U/mL for sodium taurocholic substrate. The recorded levels of bile salt activity were 0.52-1.26 µmol/mL for the sodium glycocholate substrate and 0.43-0.9 µmol/mL for the sodium taurocholic substrate. The percentage of assimilated cholesterol ranges from 38.69% to 71.98%.

Food Production Scheduling: A Thorough Comparative Study between Optimization and Rule-Based Approaches

This work addresses the lot-sizing and production scheduling problem of multi-stage multi-product food industrial facilities. More specifically, the production scheduling problem of the semi-continuous yogurt production process, for two large-scale Greek dairy industries, is considered. Production scheduling decisions are made using two approaches: (i) an optimization approach and (ii) a rule-based approach, which are followed by a comparative study. An MILP model is applied for the optimization of short-term production scheduling of the two industries. Then, the same problems are solved using the commercial scheduling tool ScheduleProTM, which derives scheduling decisions using simulation-based techniques and empirical rules. It is concluded that both methods, despite having their advantages and disadvantages, are suitable for addressing complex food industrial scheduling problems. The optimization-based approach leads to better results in terms of operating cost reduction. On the other hand, the complexity of the problem and the experience of production engineers and plant operators can significantly impact the quality of the obtained solutions for the rule-based approach.

Effects of Dairy Cows Management Systems on the Physicochemical and Nutritional Quality of Milk and Yogurt, in a North-Eastern Romanian Farm

The study’s objective was to investigate changes in the fatty acid composition of cow milk in general and in 80 Romanian Spotted cows’ husbandry and feeding systems in particular (grazing–GC group vs. stabulation–SC group). The ultimate objective was to determine if the changes that happened in the milk also transferred to the finished product. Also, the influence of the quality of raw milk produced by both systems was evaluated when yogurt was made from it. The milk was gathered in May, July and September and used for both the yogurt-making process and the study, which lasted from May to October. In comparison to milk from SC, milk from grazed caws had larger percentages of fat and dry matter throughout the summer (GC) season. Moreover, pasture-based rations (MGC) contained more PUFA than MCS did. Data research revealed that not only do factors such as milk origin and initial quality have a substantial impact on yogurt quality parameters, but also technologies such as milk fermentation have a considerable impact on the fatty acid profile of yogurt. In comparison to cows kept permanently in stables, grazed cows (MGC) had fat with a lower concentration of saturated fatty acids and a higher proportion of rumenic, vaccenic and oleic acids (MSC). When fresh milk is processed into yogurt and other dairy products, the fatty acid profiles alter, with saturated fatty acids predominating over unsaturated ones. The findings show that pasture-fed cows have a positive impact on milk quality, particularly in terms of fatty acid profile, as well as on yogurt’s ultimate nutritional and dietary quality.

Assessing Bottled Unfortified Natural Yogurt Product Quality of Different Brands or Unbranded Sold in New Valley Governorate, Egypt

Assessing Bottled Unfortified Natural Yogurt Product Quality of Different Brands or Unbranded Sold in New Valley Governorate, Egypt

Quality indices of ice cream produced from dairy milk partially substituted with Bambara groundnut (Vigna subterranean (L)Verdc.) beverage

The most important ingredient in ice cream production is milk. However, keeping the body, structure, and texture of ice cream requires maintaining the right balance of various constituent ingredients. Recently, a number of plant-based milk alternatives have emerged with reduced particle size distribution. Although Bambara groundnut milk (BGNM) beverage appears increasingly applicable in yoghurt production, there is paucity of relevant literature reporting its application in ice cream production. In order to supplement the existing information, this work investigated the quality indices of ice cream from dairy milk partially substituted with Bambara groundnut beverage. Different proportions of dairy milk and BGNM blended to produce ice cream involved seven formulations (100:0, 0:100, 90:10, 80:20, 70:30, 60:40 and 50:50, all v/v %). Quality indices measured included the antinutrients (phytic acid and tannins), physicochemical, microbial and sensory aspects. The obtained results showed that fat and ash content decreased with increased substitution of dairy milk, whereas the protein, carbohydrate, calcium, iron, potassium and magnesium contents increased with addition of Bambara groundnut. In addition to statistical differences that occurred across the samples (p<0.05) in most cases, with varying ranges from pH (5.20-6.61), overrun (11.00-73.50%), total solids (10.98-12.35%), viscosity (1.00-2.25 Pa.s), to total titratable acidity (0.05-0.11 g/100 mL). Besides the increased meltdown values, and the somewhat varying anti-nutrients (tannin = 0.32-2.64 mg/100 g; phytic acid = 2.97-63.85 mg/100 g), the total viable count ranged from 1.2 x 103 to 8.7 x 102 CFU/mL, while sensory characteristics had quite a number of resemblances (p>0.05) between some samples. This current work has demonstrated a desirable ice cream can be produced by partially substituting dairy milk with up to 30% Bambara groundnut extract.

Optimized fermentation conditions for dragon fruit yogurt

Flavored yogurt which includes fruit yogurt is more popular with consumers, the addition of fruit to yogurt improves the flavor making the yogurt product more appealing to consumers. Dragon fruit has been used in yogurt production to enhance the nutritional and physiological characteristics of final product. However, limited information exists on optimizing the processing parameters of dragon fruit yogurt production. This study, therefore, adopted a central composite design to optimize the processing parameters of dragon fruit yogurt production and evaluated the statistical relation between the independent factors (dragon fruit puree, milk powder, corn starch, and fermentation time) and their responses (viscosity, syneresis, pH and titratable acidity). Results indicated that milk powder and fermentation time were the principal factors that affect the various responses. Based on the surface response models, the optimum formulation conditions for dragon fruit yogurt were dragon fruit puree (31.42 g), corn starch (7.0 g), milk powder (49.02 g), and fermentation time (6.0 hr). This produced a measured response of pH (4.77 ± 0.12), viscosity (30.33 ± 9.29 cP), syneresis (25.24 ± 5.36 %), and titratable acidity (1.05 ± 0.03 %). The optimum fermentation conditions had a favorable effect on the response values, suggesting that dragon fruit yogurt production could benefit from the optimized formula.

The Effects of Yoghurt Acid Whey Marination on Quality Parameters of Pork and Chicken Meat.

Large amounts of yoghurt acid whey (YAW) are annually generated as a result of Greek-style yoghurt production, which poses a great hazard to the environment. In terms of sustainability, YAW application in the meat industry appears as a great alternative since meat marination with natural solutions is a practice that continuously gains ground due to its positive effects on meat sensory attributes. The aim of the present study was to determine the quality characteristics and oxidative status of pork and chicken meat after their marination in yoghurt acid whey. Forty samples per meat type were randomly assigned into five groups: CON, without YAW marination; YAW1 and YAW3, in which meat was marinated at 4 °C and a pH of 4.5 for 15 and 10 h, respectively; or YAW2 and YAW4, in which meat was handled as in the YAW1 and YAW3 group, respectively, while hesperidin at 2 g/L was also incorporated into the marinade. As shown, meat shear force values were decreased in pork but not in chicken meat samples. Meat pH values were also generally decreased, while lightness was increased in raw but not in cooked meat samples as an effect of marination. Moreover, meat oxidative stability was improved to a greater extent in chicken than in pork meat. In order to find the ideal marination period for pork meat, we further immersed it into YAW for 5 h. However, this treatment affected neither meat tenderness and the other quality properties nor meat oxidation rates. In general, hesperidin addition did not have an additional or side effect on the quality traits of pork and chicken meat. As it can be concluded, pork meat marination in YAW for 10-15 h improves tenderness, but 5 h of marination does not. On the other hand, the tenderness of chicken meat was not affected, but its oxidative stability was greatly improved after remaining in the YAW marinade for 10-15 h.

Effect of the traffic-light system on nutrition labeling in processed food products in the Ecuadorian population

Abstract The 2012 Ecuadorian National Nutrition and Health Survey found that a high proportion of the country's population is overweight or obese. To address this health issue, in 2013, the Ecuadorian government implemented the use of a mandatory traffic-light (TL) nutritional labeling to be displayed on all processed food and beverages for sale in the country. We aimed to evaluate Ecuadorian consumers’ preferences for the nutritional attributes represented in the TL nutritional labels. In this cross-sectional study, 1,152 Ecuadorian consumers aged 18 and older in charge of food purchases completed an online survey. Results of a choice experiment with yogurt products revealed strong preferences and willingness to pay for yellow and green labels reaching price premiums of $1.15 for fat and $1.34 for sugar relative to red labels. The study provides evidence that consumers have high understanding of the TL nutritional labeling and prefer products with colors representing healthier alternatives.

Milk Yield and Composition, Technological Properties and Homeostasis Indices at Different Lactation Stages and Parities of Two Polish Dairy Goat Breeds

Abstract The purpose of the research was to determine the effect of breed, lactation number, and lactation stage on milk efficiency and goat milk ingredients, these being indicators of milk technological parameters and homeostasis disturbances. Goat breed and number of lactation affected energy-corrected milk, value-corrected milk yield, fat corrected milk, protein, casein, lactose contents and free fatty acids. Additionally, differences in non-fat solids and urea contents were found between two Polish common dairy breeds White Improved (PWI) and Fawn Improved (PFI) goats. Moreover, parity affected milk yield, its acidity and somatic cell count (SCC). Milk yield and milk components were found to vary according to lactation stage. At the beginning of lactation, milk is richer in ingredients which have effect on cheese and yoghurt production. All the goats undergo similar changes related to the lactation stage that is at the same time and this can affect the yield and quality of the curd. In production focused on liquid milk, the age structure of the herd should be properly managed, as the goats in their third lactation or above have higher milk yields, regardless of breed. For cheese production, the PWI breed would be more suitable than PFI as the PWI goat milk contains less SCC and more components essential for milk processing, including caseins.

Trends and prospects in dairy protein replacement in yogurt and cheese

There is a growing demand for nutritional, functional, and eco-friendly dairy products, which has increased the need for research regarding alternative and sustainable protein sources. Plant-based, single-cell (SCP), and recombinant proteins are being explored as alternatives to dairy proteins. Plant-Based Proteins (PBPs) are commonly used to replace total dairy protein. However, PBPs are generally mixed with dairy proteins to improve their functional properties, which makes them dependent on animal protein sources. In contrast, single-Cell Proteins (SCPs) and recombinant dairy proteins are promising alternatives for dairy protein replacement since they provide nutritional components, essential amino acids, and high protein yield and can use industrial and agricultural waste as carbon sources. Although alternative protein sources offer numerous advantages over conventional dairy proteins, several technical and sensory challenges must be addressed to fully incorporate them into cheese and yogurt products. Future research can focus on improving the functional and sensory properties of alternative protein sources and developing new processing technologies to optimize their use in dairy products. This review highlights the current status of alternative dairy proteins in cheese and yogurt, their functional properties, and the challenges of their use in these products.

Product development of Amorphophallus muelleri Bl. Synbiotic yogurt using Quality Function Deployment method

The COVID-19 pandemic has significantly changed and impacted various aspects of life. The customer behavior of the Indonesian people has changed during this pandemic. Increasing public awareness of health is an opportunity to develop functional foods which can improve the body’s immune system. Some probiotic dairy products, e.g., yogurt, are currently being developed with the addition of prebiotics and are also known as synbiotic yogurt. This research aims to develop an Amorphophallus muelleri Bl. Synbiotic yogurt product design based on customer requirements and engineering characteristics. The method used in this study is the Quality Function Deployment (QFD) method. Quality Function Deployment is a method to develop product design quality to achieve customer satisfaction. The results showed that the product attributes customers want for yogurt include a rather strong aroma, a slightly sour and sweet taste, a thick texture, and a production volume of 250 ml packaged in cup packaging.

In-Vitro Inhibitory Efficacy of 3 Types of Probiotics on the Growth of Aggregatibacter actinomycetemcomitans Bacteria.

Amongst the specific plaque pathogen Aggregatibacter actinomycetemcomitans (Aa) ATCC 43718 serotype b is one of the highly virulent bacteria that causes periodontitis. Probiotic therapy is a treatment in which the lactic acid bacteria in are utilized to impede the colonization and growth of the pathogenic bacteria to prevent the further formation of dental plaque. The present research aimed to evaluate inhibiting effect of purified bacteria from various commercially available yogurt product containing bacteria named (Lactobacillus casei strain Shirota; Lactobacillus bulgaricus and Streptococcus thermophilus; Lactobacillus reuteri Prodentis) on the growth of Aa. The research made use of the diffusion method by fixing Aa on BHIB (brain heart infusion broth) medium, incubated at 37 °C and 24 hours later planted on MHA (Mueller-Hinton agar) media. Aa were divided into four subgroups each with a paper disk; group 1 consists of untreated bacteria (i.e., control group), group 2 with purified bacteria from Yakult 0.5 μL, group 3 with purified bacteria from Cimory Yogurt Drink 0.5 μL and group 4 with purified bacteria from BioGaia Prodentis 0.5 μL. All commercially available yogurt were treated to get the purified probiotic. Additionally, it was incubated for 24 hours at 37 °C and later the inhibition zone diameter was observed. In the research, it was found that the average impeding ability, so-called inhibition zone, in group 1 indicated 0 mm, group 2 indicated 12.70 mm, group 3 indicated 16.60 mm and group 4 indicated 19.60 mm. The statistical test outcomes showed a significance of 0.000 (p < 0.05). The purified bacteria from three probiotics indeed inhibit the growth of the Aa bacteria and a substantial difference in the diameter of the inhibition zone were found among the three probiotics.

Enrichment of Lactoferrin and Immunoglobulin G from Acid Whey by Cross-Flow Filtration.

The production of cream cheese, curd, high-protein yogurt, or caseinate results in large amounts of acid whey as a by-product. So far acid whey is often disposed as animal feed or organic fertilizer. However, these approaches ignore the valorization potential that arises from the unique composition of the whey protein fraction. Whey contains the biofunctional proteins lactoferrin and immunoglobulin G, which possess immune-supporting, antibacterial, antiviral, and numerous further health-promoting functions. However, the concentration of these proteins in bovine milk or whey is below a physiologically relevant level. Based on literature research we specified a daily intake of 200 mg lactoferrin as the minimal functional dose. By means of cross-flow ultrafiltration, an attempt was made to increase the concentration of biofunctional proteins. Therefore, a membrane for the selective retention of lactoferrin and immunoglobulin G was identified, and the process parameters were optimized. Finally, a concentration experiment was conducted, whereby the concentration of biofunctional proteins was increased up to factor 30. The biofunctionality was assessed in a microbiological assay. Surprisingly, the antimicrobial growth inhibition of the produced concentrate was even higher than in pure lactoferrin. The presented approach offers a strategy to convert an abundant but underutilized by-product into valuable products for human nutrition.

Antibiotic Resistance Profile of Indigenous Streptococcus thermophilus and Lactobacillus bulgaricus Strains Isolated from Traditional Yogurt

Antibiotic resistance signifies a safety hazard to public health. Lactic acid bacteria, particularly, Streptococcus thermophilus and Lactobacillus bulgaricus, are useful organisms responsible for dairy fermentation. In keeping with this, they may transfer antibiotic resistance to human population. We conducted a study exanimated the antibiotic resistance pattern and distribution of antibiotic resistance genes of the S. thermophilus and L. bulgaricus strains isolated from traditional yogurt samples. Fifty-five traditional yogurt samples were collected, and S. thermophilus and L. bulgaricus strains were isolated using the microbial culture. The disk diffusion method in agar wells was utilized to assess the antibiotic resistance pattern of isolates against 13 antibiotic agents. The distribution of antibiotic resistance genes was assessed using conventional PCR. Lactobacillus bulgaricus and S. thermophilus were identified in 94.54% (52/55) and 87.27% (48/55) of yogurt samples, respectively. Both L. bulgaricus and S. thermophilus bacteria were simultaneously identified in 72.72% of samples. Streptococcus thermophilus isolates harbored the highest antibiotic resistance rate against tetracycline (31.25%), ampicillin (31.25%), gentamicin (25%), erythromycin (25%), penicillin (12%), and ciprofloxacin (20.83%). Lactobacillus bulgaricus isolates harbored the highest resistance rate against tetracycline (9.61%), ampicillin (9.61%), gentamicin (9.61%), and erythromycin (7.69%). Streptococcus thermophilus (33.33%) isolates harbored the higher distribution of multidrug resistance than L. bulgaricus (11.53%). aacA-D (20.83%), tetK (16.66%), ermA (14.58%), blaZ (14.58%), and gyrA (12.50%) were the most commonly detected antibiotic resistance genes in S. thermophilus. AacA-D (3.84%) and tet K (3.84%) were the most commonly detected antibiotic resistance genes in L. bulgaricus. Lactobacillus bulgaricus isolates did not harbor tetM, cat1, rpoB, vanA, linA, and strA-strB antibiotic resistance genes. Streptococcus thermophilus and L. bulgaricus strains used in traditional yogurt production can harbor antibiotic resistance genes and subsequently disseminate the resistance to human beings. Monitoring antibiotic resistance in fermented foods should be a common inspection for food quality.

Rheological, Physicochemical, Microbiological, and Aroma Characteristics of Sour Creams Supplemented with Milk Protein Concentrate.

Milk protein concentrate (MPC) is widely used to enhance the stability and texture of fermented dairy products. However, most research has focused on yogurt products, and the effects of MPC on sour cream characteristics remain unknown. Therefore, we investigated the effects of different MPC levels (0%, 1%, 2%, and 3% w/w) on the rheological, physicochemical, microbiological, and aroma characteristics of sour creams in this study. We found that MPC supplementation stimulated the growth of lactic acid bacteria (LAB) in sour creams, resulting in higher acidity than that in the control sample due to the lactic acid produced by LAB. Three aroma compounds, acetaldehyde, diacetyl, and acetoin, were detected in all sour cream samples. All sour creams showed shear-thinning behavior (n=0.41-0.50), and the addition of MPC led to an increase in the rheological parameters (ηa,50, K, G', and G″). In particular, sour cream with 3% MPC showed the best elastic property owing to the interaction between denatured whey protein and caseins. In addition, these protein interactions resulted in the formation of a gel network, which enhanced the water-holding capacity and improved the whey separation. These findings revealed that MPC can be used as a supplementary protein to improve the rheological and physicochemical characteristics of sour cream.

Sonication as a pre-processing step to alter acid whey generation during Greek yoghurt manufacture.

We investigated sonication as a pre-processing step to reduce acid whey generation during Greek yoghurt manufacture. The generation of a large amount of acid whey during the production of Greek yoghurt is an ongoing problem in the dairy industry and many studies are currently focusing on reducing it. We focused on the use of ultrasonication as a novel approach to minimize the casein fraction in the acid whey stream and simultaneously improve the gel properties. Ultrasound applied before the fermentation modified the structural properties and bonding behaviours of milk proteins, and enhanced the retention of casein in the yoghurt gel after the fermentation and straining steps. Therefore, the use of low-frequency ultrasonication as a pre-processing step may have the potential to provide significant economic benefits to the Greek yoghurt manufacturing process. Moreover, it improved the nutritional and physicochemical properties compared to regular Greek yoghurts.