Search

The aim of this study is to investigate the effects of herbal supplements administered to goats on sensory quality and volatile flavor compounds in their milk. The experiment was conducted on sixty Polish white improved goats randomly allocated into five feeding groups (four experimental and one control) of twelve goats each. The trial lasted 12 weeks. The experimental animals received supplements containing a mixture of seven or nine different species of herbs at 20 or 40 g/animal/day. The control group received feed without any herbal supplements. Milk obtained from experimental and control groups of animals was characterized by a low content of aroma compounds, with only 11 chemical compounds being identified. Decanoic methyl ester, methylo 2-heptanone and methylo-butanoic methyl ester had the highest share in the total variability of the tested aroma compounds (PCA). During the sensory evaluation, the smell and taste of most of the samples were similar (p > 0.05). However, the addition of herbal feed supplements lowered the concentration of Caproic acid (C6:0), Caprylic acid (C8:0) and Capric acid (C10:0), which caused a significant reduction in the goaty smell of milk. The obtained results indicate that the studied herbal supplements can reduce the intensity of goaty smell and allow goat milk production without modification of other sensory features.

Sixty dairy goats of the Polish white improved breed were randomly assigned to five feeding groups of twelve animals each. The animals received a supplement containing seven herbs at 20 or 40 g/animal/day (experimental groups 1 and 2) and a supplement containing nine herbs at 20 or 40 g/animal/day (experimental groups 3 and 4)m, along with pelleted concentrate feed. Group 5 (the control group) received pelleted feed without any herbal supplements. A significant effect of herbal feed additive on lactic acid bacteria (LAB) count was observed (p < 0.001). The highest number density of LAB was found in the goats receiving the feed additive with nine herbs at 20 g/animal per day (p < 0.05). There was a statistically significant effect of lactation stage on intestinal LAB count (p < 0.001). Regardless of the feeding group, the highest number density of LAB was found in animals at the peak of lactation. The LAB count was also affected by the interaction of diet group × lactation stage (p < 0.0001). A probiotic strain of Lactobacillus fermentum was identified in the faecal samples of goats receiving the herbal additive, but not in the controls. Genetic identification of the microorganisms isolated from the faeces of the experimental goats did not reveal the presence of harmful mould spores, although spores of the fungus Aspergillus fumigatus were detected in the controls.

The aim of this study was to analyse the metabolic activity of lactic acid bacteria and yeast based of changes in electrical conductivity and electrical impedance during fermentation of goat milk and mixtures of goat’s milk and mare’s milk (1:1, 1:2). As a result of fermentation, conductivity increased 1.4-fold. The conductivity of kefir prepared from goat and mare milk mixed at a ratio of 1:2 (6.210 Ω-3∙cm-1) was lower than that of the 1:1 mixture or of goat milk alone (7.242 Ω-3∙cm-1). A significant dependence of electrical conductivity and pH (0.970 ≤ r ≤ 0.993) was recorded during fermentation. The addition of mare milk to goat milk significantly slowed down the growth of LAB (Δλ = 0.8 h) and yeasts during kefir production.

The aim of this study was to conduct lactic acid-alcoholic fermentation using mesophilic lactic acid bacteria (LAB) for mare’s milk and its mixture with goat and sheep milk, followed by instrumental and sensory characteristic of the texture profile in the produced kefirs. It was shown that kefirs made from a mixture of goat and sheep milk are firmer, have greater values of consistency and the viscosity index than those produced from mare’s milk alone. Kefir storage for 3 weeks causes changes in their mechanical properties. Exceptions are found for firmness of kefirs made from both mixtures and the viscosity index of kefir made from sheep milk, which remained stable. The most divergent texture profile of the tested kefirs was reflected in the sensory examined descriptors of prickling, dense and mouth-coating sensation.

Color is important for the consumer when making a purchase decision. Mare’s milk and, thus, fermented mare’s milk is little known to consumers. Thus, it is worth presenting research showing the extent of color change during the production and storage of mare’s milk. Herein, we examined the range of color changes in mare’s milk and cow’s milks adapted to mare’s milk composition. These samples were further fermented and stored for 3 weeks at 5 ± 1 °C. Starter cultures containing Streptococcus thermophilus and Lactobacillus delbrueckii subsp. bulgaricus were used for fermentation. Mare’s milk reached the required pH of 4.5 during fermentation faster (255 min) than cow’s milk (300 min). After fermentation, mare’s milk compared to cow’s milk and adapted cow’s milk had lower titratable acidity (0.75%) and firmness (145. 6 |(g∙s)|). The water holding capacity (95.6%) and number of Lactobacillus (7.71 log CFU/mL) and Streptocococcus (7.20 log CFU/mL) in mare’s and other’s milks were the same. Mare’s milk was furthest from the ideal white (WI) color, with its chrome (C*) being 1.5-times larger than cow’s milk. However, fermented mare’s milk was darker than the fermented adapted milk and cow’s milk by 36% and 58%, respectively. Storage caused a decrease in the WI, C*, and yellowness index (YI). The fermented mare’s milk color stability during production and storage was less than that of fermented cow’s milk. After 3 weeks storage, it was observed that the titratable acidity increased to 1.05%, and the pH decreased to 4.3 in fermented mare’s milk. The water holding capacity decreased but was still higher compared to fermented cow’s milk.

The study assessed cheese meltability at elevated temperatures, based on the results of the Tube Test and Schreiber Test. The tests were conducted on curd-ripened fried cheese with varying fat contents (Δfat = 17%) and at different storage times (Δt = 6 weeks). The protein:fat ratio in full fat cheese was C:F≍1, while in low-fat cheese it was C:F≍58. The data on cheese meltability recorded in the Tube Test and Schreiber Test, irrespective of experimental variables, indicated a high degree of correlation (r = 0.95). However, the lowest convergence (r = 0.6) of both methods was found when analysing low fat cheese. A higher fat content in the tested cheeses resulted in a statistically significantly higher meltability both in the Tube Test (by 12%) and in Schreiber Test (by 18%). The analysis of the regression model and response surfaces of variables confirms the trend showing that the lower the fat content and the longer the sample storage time, the lower the meltability. After 6 weeks the assessed meltability of cheeses was lower by 20.7% in the Tube Test, and by 19.1% in the Schreiber Test in comparison to the meltability of cheeses assessed immediately after their production.

Cow milk and goat milk can be used to produce fermented milk drinks, which have different properties. To use goat milk as a raw material, the fermentation conditions have to be carefully adapted to receive an optimal product. The aim of this study was to find the most appropriate starter culture for producing a health-promoting goat beverage. The improvement of the quality of fermented goat beverage was done by selection of specific microbial strains and to define a ratio between the compounds of the starter culture. Goat milk was inoculated with starter cultures each containing two specified bacterial strains ( Lacococcus lactis and L. lactis subsp . cremoris or Sterptococcus thermophilus and Lactobacillus delbruckii subsp . bulgaricus) as well as yeasts ( Saccharomyces fragilis) in three concentrations 0.2, 0.4 or 0.6 g dm−3. The bacteria and yeasts growth and their metabolic profile was done by monitoring of the impedance. The fermentation process was characterized by pH value, alcohol content, color, and texture changes. Sensory evaluation of the final product was also performed. It was found that the use of L. lactis, L. lactis subsp . cremoris, and S. fragilis at 0.2 or 0.4 g dm−3 gave the most satisfying results and can be successfully utilized in goat milk fermentation. [ABSTRACT FROM AUTHOR]