Nutritional and health-promoting quality of organic milk of Saanen goats and Jersey cows and yoghurt produced from it

Aim:The study was undertaken to find out the physicochemical characteristics, selected processing-related parameters and activity of selected enzymes in Surti goat milk.Materials and Methods:Milk samples from Surti goats and buffalo milk samples were collected during the period from July 2013 to January 2014 at Reproductive Biology Research Unit, Anand Agricultural University (AAU), Anand. Milk samples from Kankrej cows were collected from Livestock Research Station, AAU, Anand. Samples were analyzed for physicochemical characteristics such as acidity, viscosity, surface tension, specific gravity, refractive index, freezing point, and electrical conductivity. Samples were also analyzed for selected processing-related parameters such as heat coagulation time (HCT), rennet coagulation time (RCT), rate of acid production by starter culture, alcohol stability, and activity of selected enzymes such as alkaline phosphatase activity, catalase activity, proteolytic activity, and lipase activity.Results:Goat milk had the highest acidity, viscosity and surface tension, followed by cow milk and buffalo milk. However, the differences in acidity, specific gravity, surface tension, refractive index, electrical conductivity, HCT and lipase activity of three types of milk studied, viz., goat, cow, and buffalo milk were found statistically non-significant (p<0.05). The buffalo milk had the highest specific gravity, followed by those found in cow and goat milk. The viscosity, freezing point and RCT of goat milk was significantly lower (p>0.05) than that of the buffalo milk. However, the difference in viscosity, freezing point and RCT of goat milk and that of the cow milk was statistically non-significant. The cow milk had the highest refractive index, followed by goat and buffalo milk. The cow milk had the highest proteolytic activity and heat coagulation time (HCT), followed by those found in buffalo and goat milk. The goat milk had the lowest freezing point, lipase activity, and RCT, followed by those found in cow and buffalo milk. The goat milk had the highest electrical conductivity, followed by those found in buffalo and cow milk. The collected goat, cow and buffalo milk samples showed negative stability at 68% (v/v) alcohol concentration. Goat milk showed positive alcohol test at 75% (v/v) alcohol concentration. Acidity was found to increase proportionally with time. After 14 h, it was found that goat milk became thicker, but the curd had a very low consistency. Cow milk had the highest alkaline phosphatase activity and catalase activity followed by those found in goat milk and lowest alkaline phosphatase activity and catalase activity was found in buffalo milk. The alkaline phosphatase activity and proteolytic activity of goat milk was significantly lower (p>0.05) than that of the cow milk. However, the difference in alkaline phosphatase activity and proteolytic activity of goat milk and that of the buffalo milk was statistically non-significant. Alkaline phosphatase activity of buffalo milk was significantly lower (p>0.05) than that of the alkaline phosphatase activity in cow milk.Conclusion:It can be concluded from the study that the goat milk has highest acidity, viscosity, electrical conductivity, and surface tension compared to that of cow and buffalo milk. The goat milk has lowest specific gravity, freezing point, proteolytic activity, lipase activity, RCT and HCT compared to cow and buffalo milk. Goat milk had highest refractive index compared to buffalo milk, whereas lowest refractive index compared to cow milk. Goat milk showed positive alcohol test at 75% (v/v) alcohol concentration. The curd formed from goat milk after 14 h was having very weak consistency. The goat milk has higher alkaline phosphatase activity, catalase activity compared to buffalo milk while it has lower alkaline phosphatase activity, catalase activity compared to cow milk.

Cross-reactivity between milk proteins of different animals.

Some factors affecting lipase activity in goat milk

Effect of goat milk, cow milk, cow milk replacer and partial substitution of the replacer mixture with whey on artificial feeding of female kids

The contents of macro- and microelements in cow, goat, and human milk from Croatia were measured and compared for the first time. The highest concentrations of element were measured in milk cow: calcium 1.4 g/kg, sodium 0.6 g/kg, zinc 4.0 mg/kg, strontium 0.4 mg/kg; goat: magnesium 0.2 g/kg, potassium 2.2 g/kg, iron 0.8 mg/kg, manganese 71 µg/kg, selenium 35 µg/kg, molybdenum 20 µg/kg, chromium 72 µg/kg, lithium 14 µg/kg; and human: copper 193 µg/kg. Equal content of molybdenum (20 µg/kg) was determined in cow and goat milk. Significant differences in element levels between the three species were determined. Concentrations of magnesium, manganese, selenium, chromium, and lithium in goat milk were significantly higher than in cow milk. Significantly lower levels of calcium, potassium, sodium, magnesium, zinc, selenium, and strontium were determined in human milk than in cow and goat milk. Chromium content was significantly higher in goat than in human milk. Copper content in human milk was significantly higher than in cow milk. Correlations, mostly moderate and positive, were found between elements in cow and goat milk.

Due to its medicinal benefits in mouth ulcers, dengue fever, etc. raw goat milk is widely used but ingestion of raw goatmilk may have severe side effects. Aflatoxin M1 is produced by Aspergillus species and under long-term exposure, these are mutagenic, genotoxic, and carcinogenic. This study examined the shelf life of raw goat and cow milk at different storage temperatures (including ambient temperature, 5°C, and -19°C),via analysis of microbiological quality by standard plate count method. Incidence of aflatoxin M1 was also studied in raw goat and cow milk samples by lateral flow system. Cow milk showed as helf life of 12 days while goat milk had up to 48 days at 5°C. The total plate count, coliform count, and spore count of goat milk was reported 5.89 log cfu/mL, 2.80 log cfu/ml, and 2.3 log cfu/mlin 75 days of storage while in cow milk samples it was 7.93 logcfu/ml, 5.64 log cfu/ml and 3.6 log cfu/ml, respectively in 45 day sat -19°C. All the goat milk samples were found negligible for Aflatoxin M1 while cow milk samples showed a 40% incidence at0.5 ppb. Our study showed that the quality of goat milk is commendable compared to cow milk in terms of aflatoxin M1 and bacterial count but due to less production and other factors goatmilk is not widely used at the commercial level.

Physico-chemical characteristics of goat and sheep milk

This study was carried out to determine the intensity of production of acetic acid, short (SCFA) and medium (MCFA) chain fatty acids in cow and goat milk fermented by the use of Bifidobacterium longum Bb-46. Amounts of SCFA and MCFA in fermented goat and cow milk were determined by the use of GC/FID method. Concentration of acetic acid in the samples of fermented goat and cow milk were measured using GC/MS method. Furthermore, the growth rates of Bifidobacterium longum Bb-46 and its fermentation activity in goat and cow milk were also determined. Obtained results suggest higher metabolic activity of Bifidobacterium longum Bb-46 in goat than in cow milk. Bifidobacterium longum Bb-46 grew better in goat than in cow milk. Consequently, pH values decreased more rapidly during the fermentation of goat milk. Contents of all the examined SCFA and MCFA, as well as of acetic acid, increased more rapidly in goat milk during the whole fermentation process.

Lack of information on the quality of goat milk in Kenya and the belief that the milk has an undesirable “goaty” flavour, have been major impediments to its wider utilisation and commercialisation. The objective of the study was to determine nutrient composition of goat milk from different breeds in Kenya, and assess consumer acceptability of goat milk products. An on-station study was carried out at KALRO-Kitale on Kenyan Alpine, Toggenburg and Saanen goat breeds, during their first and second lactation stages. The quality of milk from farmers’ goats in Trans Nzoia County was also determined. There were significant differences in yield and quality of milk from different breeds. Milk from the Saanen goats had the highest levels of fat, SNF and density. Protein content did not differ significantly between the three breeds. There was great variation in composition of the milk obtained from farmers’ fields, which may be attributed to differences in the breeds, stage of lactation and feeding regimes. Panellists who tasted goat milk and products showed higher preference for goat milk than cow milk products.Key Words: Dairy goat breed, Kenyan Alpine

Detection of milk adulteration is important to maintaining the quality of milk and milk products regarding pricing and consumer protection. Thus, in the current study, we investigated the adulteration of goat milk sold in the market and labeled it as “100% Goat Milk” with cows and sheep milk by real-Time PCR reaction (RT-PCR). This study is the first investigation on goat milk in Turkey and has particular importance as it was carried out using TaqMan probe RT-PCR. In total, 60 milk samples sold in the market and labeled as “100% Goat Milk” were collected from 12 different provinces of Turkey. The RT-PCR TaqMan probe detected the adulteration of goat milk with cow and sheep milk. In the study, 18 (30%) samples were found to be compatible with the label. It was determined that 42 (70%) samples did not comply with the “100% Goat Milk” statement on the label. It was determined that 6 (10%) of the samples contained only sheep milk, 18 (30%) contained only cow milk, another 6 (10%) contained goat and cow milk, 12 (20%) contained sheep and cow milk, and 36 (60%) did not contain any goat milk. The results of this study revealed high levels of adulteration in goat milk products. Therefore, careful continuous monitoring of these products’ production and sales is necessary regarding deception of consumers and public health.

Evaluation of a commercial ELISA method for the quantitative detection of goat and cow milk in ewe milk and cheese

Assessment of the Colorimetric and Fluorometric Assays for Alkaline Phosphatase Activity in Cow's, Goat's, and Sheep's Milk

All the parameters were done for fresh, boiled, preserved & boiled preserved milk of goat. Milking was carried early in the morning between 6.00 to 7.00 am. PH of Goat milk is less than 7 .So pH of goat and cow milk is slightly acidic. The fat content in goat milk ranged from 2.3 to 6.4 mg%. And the fat content in cow milk ranged from 3.0 to 5.4 mg%. As compared to cow milk fat content in goat milk is slightly higher than cow milk. That results also observed (Simsek O et.,al 2000)The protein content in goat milk ranged from 3.2to 3.9mg%. And in cow milk ranged from 2.9to 32.3 mg%. Protein content also slightly greater than cow milk. Density in goat milk ranged from 28.38 to 38.57-g/l. & in cow milk ranged from 28.30to 29.95 g/l. highest density was observed in boil milk of goat. Sodium content in goat milk ranged 417.9. To 570.6 ppm & in cow milk ranged from 497.5 to 585.0ppm. Sodium content in cow & goat milk same. Potassium content in goat milk ranged from 942.1 to 1192.9ppm & in cow milk ranged from 1030.2 to 1194.8ppm. That results also observed (Barnes R. B et,,al 1945)

The aim of this study was to monitor the impact of heat treatment variables on the freezing point of cow and goat milk. The freezing point (FP) was established in 30 bulk tank samples of goat milk and in 30 bulk tank samples of cow milk which were subject to laboratory heat treatment at temperatures of 72 °C (A), 85 °C (B), 95 °C (C), with the same exposition times of 20 s. Freezing point measurements of raw and heat-treated milk were carried out in compliance with the Standard CTS 57 0538 by a thermistor cryoscope. The FP of raw cow milk increased with heat treatment from the initial values of -0.5252 ± 0.0114 °C (O) by 0.0023 °C (A), 0.0034 °C (B) and 0.0051°C (C). Changes in FP values of goat milk were detected, from its initial value of –0.5530 ± 0.0086 °C there was an increase in the FP depending on the mode of heat treatment due to pasteurization by an average of 0.0028 °C (A), 0.0036 °C (B) and 0.0054 °C (C). The dynamics of the changes were similar both in goat and cow milk. Freezing point values in cow and goat milk differed (P ⪬ 0.01) when compared to the freezing point of untreated milk after the individual interventions as well as when compared between each other. An increase in the heat treatment temperature of cow and goat milk causes an increase in the freezing point (a shift towards zero). These results can be used in practice for checking the raw material in dairy industry.

The aim of this study was to determine the influence of goat's milk fermented by Bifidobacterium longum Bb-46 on pathogenic Staphylococcus aureus strain, as well as to determine the differences of inhibitory potential between fermented goat's and cow's milk. The results showed significantly higher inhibitory effect of fermented goat's milk on the growth of Staphylococcus aureus compared to that of fermented cow's milk. Fermented goat's milk inhibited the growth of Staphylococcus aureus during the whole fermentation period. In contrast to fermented goat's milk, weaker inhibitory effect of fermented cow's milk was observed only during the first phase of fermentation (incompletely fermented samples with higher pH values and lower number of viable cells of Bifidobacterium longum Bb-46). The obtained results suggested that there was no correlation between changes of pH or CFU of Bifidobacterium longum Bb-46 during fermentation and the inhibitory effect of fermented cow's and goat's milk. However, the results suggested some correlation between the inhibition of Staphylococcus aureus growth and the content of SCFA and MCFA in fermented cow's milk. At the same time, considerably higher amounts of all examined SCFA and MCFA were produced in goat's milk in all the phases of the fermentation process.