Possibility of Using Different Calcium Compounds for the Manufacture of Fresh Acid Rennet Cheese from Goat's Milk.

Calcium can be added to cheese milk to influence the coagulation process and to increase cheese yield. Calcium compounds used in the dairy industry show substantial differences in their practical application. Therefore, this study aimed to evaluate the potential use of 0, 5, 10, 15, and 20 mg Ca 100 g-1 of milk in the form of calcium gluconate, lactate, and carbonate as alternatives to calcium chloride in manufacturing fresh acid rennet cheese from high-pasteurized (90 °C, 15 s) goat's milk. The pH value of the cheese was reduced most strongly by the addition of increasing doses of calcium lactate (r = -0.9521). Each cheese sample showed increased fat content with the addition of calcium. Only calcium chloride did not reduce protein retention from goat's milk to cheese. The addition of 20 mg Ca 100 g-1 of milk in the form of gluconate increased cheese yield by 4.04%, and lactate reduced cheese yield by 2.3%. Adding each calcium compound to goat's milk significantly increased Ca and P levels in the cheese (p ≤ 0.05). The highest Ca levels were found in cheese with the addition of 20 mg Ca 100 g-1 of milk in the form of lactate. In all groups, similar contents of Mn, Mo, and Se were found. Calcium addition significantly affected cheese hardness, while higher calcium concentrations increased hardness. Carbonate caused the greatest increase in the cohesiveness of cheese. The addition of calcium compounds increased the adhesiveness and springiness of cheese compared to controls. The cheese with calcium chloride had the highest overall acceptability compared to the other cheese samples. The addition of calcium carbonate resulted in a lower score for appearance and consistency, and influenced a slightly perceptible graininess, sandiness, and stickiness in its consistency, as well as provided a slightly perceptible chalky taste.

Probiotic Fermented Goat's and Sheep's Milk: Effect of Type and Dose of Collagen on Survival of Four Strains of Probiotic Bacteria during Simulated In Vitro Digestion Conditions.

Microbial tolerance of digestive stresses depends not only on the bacterial strain but also on the structure and physicochemical properties of the supply chain and the foods that contain it. In the present study, we aimed to evaluate the effects of the type of milk (ovine, caprine) and the type and dose of collagen on the viability of four probiotic strains, Lacticaseibacillus paracasei L-26, Lacticaseibacillus casei 431, Lactobacillus acidophilus LA-5, and Lacticaseibacillus rhamnosus Lr-32, during in vitro gastrointestinal digestion. The highest survival rate under simulated in vitro digestion conditions compared to the number of cells before digestion was found in two strains, L. casei and L. paracasei, where survival rates were greater than 50% in each batch. The survival rate of the L. rhamnosus strain ranged from 41.05% to 64.23%. In caprine milk fermented by L. acidophilus, a higher survival rate was found in milk with 1.5% hydrolysate than the control, by about 6%. Survival of the L. rhamnosus strain was favorably affected by the 3% addition of bovine collagen in caprine milk, which increased survival by about 14% compared to the control sample. Adding 3% of hydrolysate to sheep's and goat's milk enhanced the survival of the L. rhamnosus strain by 3% and 19%, respectively. This study reports that fermented caprine and ovine milk may be suitable matrices for the probiotic supply of commercial dairy starter cultures and promote gut homeostasis.

Effect of Collagen Types, Bacterial Strains and Storage Duration on the Quality of Probiotic Fermented Sheep's Milk.

Collagen has become popular in dietary supplements, beverages and sports nutrition products. Therefore, the aim of this study was to evaluate the possibility of using various doses of collagen and collagen hydrolysate to produce probiotic sheep's milk fermented with Lactobacillus acidophilus, Lacticaseibacillus casei, Lacticaseibacillus paracasei and Lacticaseibacillus rhamnosus. The effects of storage time, type and dose of collagen, and different probiotic bacteria on the physicochemical, organoleptic and microbiological properties of fermented sheep's milk at 1 and 21 days of refrigerated storage were investigated. The addition of collagen to sheep's milk increased the pH value after fermentation and reduced the lactic acid contents of fermented milk compared to control samples. After fermentation, the number of probiotic bacteria cells was higher than 8 log cfu g-1. In sheep's milk fermented by L. acidophilus and L. casei, good survival of bacteria during storage was observed, and there was no effect of collagen dose on the growth and survival of both strains. The addition of collagen, both in the form of hydrolysate and bovine collagen, resulted in darkening of the color of the milk and increased the sweet taste intensity of the fermented sheep's milk. However, the addition of hydrolysate was effective in reducing syneresis in each milk sample compared to its control counterpart.

Effect of Vitamin C Source on Its Stability during Storage and the Properties of Milk Fermented by Lactobacillus rhamnosus.

The enrichment of commonly consumed foods with bioactive components might be helpful in promoting health and reducing the risk of disease, so the enrichment of probiotic fermented milk with vitamin C can be considered appropriate. The effect of vitamin C addition depends on the source of origin (rosehip, acerola and ascorbic acid in powder form) on the growth and survival of Lactobacillus rhamnosus and the quality of fermented milk on the 1st and 21st day of storage was analyzed. The pH, total acidity, vitamin C, syneresis, color, texture profile and numbers of bacterial cells in fermented milk were determined. The organoleptic evaluation was also performed. The degradation of vitamin C in milk was shown to depend on its source. The lowest reduction of vitamin C was determined in milk with rosehip. The least stable was vitamin C naturally found in control milk. The addition of rosehip and acerola decreased syneresis and lightness of milk color, increasing the yellow and red color proportion. In contrast, milk with ascorbic acid was the lightest during the whole experimental period and was characterized by a very soft gel. The growth of Lactobacillus rhamnosus during fermentation was most positively affected by the addition of rosehip. However, the best survival of Lactobacillus rhamnosus was demonstrated in milk with acerola. On the 21st day of storage, the number of L. rhamnosus cells in the control milk and the milk with vitamin C was >8 log cfu g-1, so these milks met the criterion of therapeutic minimum. According to the assessors, the taste and odor contributed by the addition of rosehip was the most intense of all the vitamin C sources used in the study.

Effect of Calcium Compound Type and Dosage on the Properties of Acid Rennet Goat's Milk Gels.

The aim of this study was to determine the effect of adding calcium compounds to processed goat's milk, and on the properties of acid rennet goat's milk gels, which are a middle product obtained in the manufacture of acid rennet cheese. The properties of the gels directly affect the quality of acid rennet cheeses. The analysis of raw goat's milk was carried out, then acid rennet gels were produced with the addition of six different calcium compounds (chloride, citrate, bisglycinate, gluconate, lactate, and carbonate). The dynamics of milk fermentation were performed by monitoring the pH value of milk during acidification. The pH, syneresis, color, and texture profile were determined in the formulated acid rennet gels. An organoleptic evaluation was also performed. The study demonstrated that, not only calcium chloride, but also calcium citrate, gluconate, lactate, bisglycinate, and calcium carbonate could be used in the production of goat's milk acid rennet gels, or the middle product in the manufacture of acid rennet curd cheese from goat's milk. Notably, the addition of citrate, bisglycinate, and calcium carbonate in doses of 20 mg Ca 100 g-1 most effectively reduced syneresis compared to the control sample by 4.76% (citrate), 7.85% (bisglycinate), and 10.28% (carbonate). The hardness of the control gels ranged from 2.35 N to 2.99 N. The addition of chloride, citrate, gluconate, lactate, and calcium carbonate to the milk improved the acid rennet gel's hardness. The addition of 20 mg Ca 100 g-1 as gluconate increased the hardness the most (3.61 N). When increasing the calcium dosage in the form of all compounds, there was a tendency to increase the gel's springiness. The addition of chloride, citrate, and bisglycinate to milk did not result in a darkening of the gel's color. The addition of calcium compounds mostly reduced the intensity of goatish taste and odor. Calcium gluconate, in particular, reduced the goatish taste the most, a taste which is not always acceptable by the consumers.

Quality of yogurt fortified with magnesium lactate.

BACKGROUND: Magnesium is a micronutrient which plays an important role in a wide range of fundamental cellular reactions. Deficiency of magnesium leads to serious biochemical and symptomatic changes. The present study was carried out to establish the influence of magnesium lactate fortification on the physico- chemical, microbiological and rheological properties of fat-free yogurt manufactured using different starters. METHODS: In this study, yogurts were produced from fat-free milk, standardized with skimmed milk powder to 6% protein content, and then divided into two parts. One part was left without supplementa- tion as a control and in the second part, magnesium L-lactate hydrate was added in the amount of 317.30 mg 100 g–1, which was equal to 35 mg of Mg2+ 100 g–1 of milk. Both mixtures were blended, pasteurized at 85°C for 30 minutes, cooled to 45°C and then divided into three parts, inoculated with: (1) YC-X11 yogurt cul- ture, (2) YF-L811 yogurt culture and (3) VITAL yogurt culture supplemented with probiotics (Lactobacillus acidophilus, Bifidobacterium lactis) respectively. Fermentation was performed at 43°C and the final yogurts were cooled to 5°C. After 24 hours of cold storage, the pH values, titratable acidity, syneresis, color, texture profile, viscosity, sensory analysis and microbiology of the yogurts were analyzed. RESULTS: The results showed that addition of magnesium lactate significantly reduced syneresis and increased the hardness of fat-free yogurts. There was no impact on the viability of starter bacteria in the yogurts after 24 hours of refrigerated storage. CONCLUSIONS: Magnesium lactate showed good potential for the fortification of dairy foods, according to physicochemical data. Further research is needed regarding the influence of storage time and to establish whether the observed effects are largely due to the magnesium cation or lactate anion.

Effect of addition of wild garlic (Allium ursinum) on the quality of kefirs from sheep's milk.

BACKGROUND: Sheep’s milk has a high content of total solids, which qualifies it as a very good raw material for the production of fermented milk drinks. Currently, there are commercially produced kefirs and yogurts from sheep’s milk in the countries of the Mediterranean region. The growing interest in the consumption of these products is justified not only by their taste merits, but also because of their health-promoting proper- ties. The aim of the present study was to determine the effect of the addition of 1% of lyophilized wild garlic powder on the properties of kefirs from sheep’s milk. METHODS: Sheep’s milk was pasteurized (85°C, 30 min), cooled down, enriched with 1% of freeze-dried wild garlic powder, inoculated with a Commercial VITAL kefir culture and fermented for 16 hours (26°C). The influence of wild garlic on acidity (pH, °SH), syneresis (%), texture (TPA test), colour (L*a*b*) and the sensory profile of kefirs was conducted. RESULTS: Wild garlic could be used as a taste and flavour modifier in the production of kefir from sheep’s milk. The addition of 1% of freeze-dried wild garlic slowed down the fermentation of kefir, changed colour and reduced syneresis. CONCLUSIONS: Wild garlic could be used as a valuable supplement and a modifier of taste and flavour in kefir from sheep’s milk.

The influence of the dose of calcium bisglycinate on physicochemical properties, sensory analysis and texture profile of kefirs during 21 days of cold storage.

BACKGROUND: In the process of enrichment of dairy products a priority element is the proper selection of compounds that are a mineral carrier. Calcium bisglycinate is better absorbed by the body than inorganic forms of calcium. Moreover, the lactic acid which is produced in kefir fermentation and the presence of lactose have also a positive effect on the improvement of absorption of calcium. The aim of the present study was to determine the influence of the applied dose of calcium in the form of calcium bisglycinate on the physicochemical and sensory properties and texture of kefirs during 21-day period of cold storage. METHODS: Processed cow milk was enriched with 0, 5, 10, 15, 20, 25 and 30 mg of calcium (for 100 g of milk), repasteurized (72°C, 1 min), cooled down (26°C), inoculated with Commercial VITAL kefir culture (Danisco, Poland) and fermented for 16 hours (26°C). The assessment of the influence of addition   of calcium bisglycinate on acidity, syneresis, texture and sensory characteristics (1-9 points) of kefirs was conducted at four fixed dates (after 1 day, 7 days, 14 days and 21 days of storage). RESULTS: During successive weeks of cold storage in all experimental groups there was observed a tendency to decrease general acidity. On the 1st and 7th days of cold storage reduced whey leakage was observed in kefirs enriched with 25 mg and 30 mg Ca/100 g of milk. With increasing doses of enrichment with calcium both the hardness, adhesiveness and gumminess of kefirs decreased. The applied doses of calcium did not cause changes in the sensory characteristics such as colour and consistency of the fermented beverages. CONCLUSIONS: Calcium bisglycinate may be used to enrich kefirs with calcium even with 30 mg of calcium in 100 g of milk without the modification of the product's parameters.