Physicochemical and Mineral Content of Milk from Talesh Buffalos, Sheep, Goats, and Cows, Saanen Goats and Talesh-Mediterranean Buffalos: A Comparative Analysis

Milk is the most nutritionally complete food that can be utilized by humans. For this reason, one of the main livestock activities in the world is raising dairy cattle. Milk comprises a complex compound that contains fats, proteins, lactose (and other sugars), minerals, vitamins, enzymes and water, as well as less-defined but nonetheless important active constituents (Piacenza et al., 2021). Dairy products are the best source of calcium for the human body (Polzonetti et al., 2020). Consumption of milk and its various products, especially fermented products, leads to increased life expectancy, increased physical and mental efficiency, reduced infectious diseases, reduced bone diseases and optimal growth of children and adolescents (Tripathi et al., 2019).

Due to the growing awareness of consumers about the relationship between diet and human health, food quality especially livestock products has become an important issue in food selection. Therefore, the consumption of foods that have beneficial effects on human health (useful foods) is increasing due to their high nutritional value. On the other hand, these foods should have a clear effect on health, or reduce serious diseases in humans. Milk is an example of one of these foods (Schröder and Vetter, 2013). Therefore, milk can be a very important food for human beings and contains almost all required nutrients (Ziarati et al., 2018). Milk and its products have been among the most important nutrients for human needs for thousands of years, which in addition to having great nutritional value, also play an important role in preventing many diseases. Numerous studies have shown the positive effect of milk and its products on human health and longevity (Ekmekcioglu, 2020). Milk and its products are a rich source of many nutrients such as protein, calcium, phosphorus, vitamin B2 and vitamin B12, which are recommended for daily human consumption. Milk provides the calcium needed to have strong bones, the protein needed for brain growth and body tissue growth, the vitamin A needed for normal vision, and the vitamin D needed to absorb calcium (Wimalawansa et al., 2018).

Daily consumption of milk in the household can, nonetheless, be very important to overall human health. Milk consumed by households globally, and in Iran specifically is generally provided by cows, followed by buffaloes and goats. Buffalo milk has a high nutritional value after sheep milk due to its high content of solids (fat, protein, carbohydrates, calcium, phosphorus and vitamin A). Thus, multiple aspects of nutritional value in buffalo milk increases the quality and health value of buffalo dairy products (Garau et al., 2021).

In Iran, about 89% of the total milk production of the country is obtained from cows. Sheep and goat milk provided 7 and 3% respectively with the remainder including buffalo and camel milk (Statistics Center of Iran, 2012). Dairy processing supplies dairy producers with more cash than raw milk sales and offers better opportunities to reach local and urban markets. Milk processing also provides the opportunity to cope with seasonal fluctuations in milk supply. Converting raw milk to processed milk and other products can benefit all communities by creating off-farm jobs in milk collection, transportation, processing and marketing (FAO, 2019).

Approximately 150 million households worldwide produce milk. In the last three decades, world milk production has grown by more than 50%. Among lactating animals, cows have the largest share of milk production in the world with 83%, the rest of the milk production is related to buffalo, sheep, goats, and other animals (Adesogan and Dahl, 2020).

The main constituents of milk are water, fat, lactose, whey proteins and minerals (ash). The composition of milk is very variable and. In addition, genetic, physiological, and nutritional factors, as well as environmental conditions, play a large role in creating these differences. Fat is the most variable component of milk, which varies even throughout the day and depends on the individual characteristics of the animals (Pietrzak-Fiećko and Kamelska-Sadowska, 2020).

Research findings indicate that mineral and trace element content in milk varies depending on species and breeds, lactation number, nutritional status, mineral supplements, geographical conditions, and environmental chemical contaminants (Park et al., 2017).

Some species are targeted for milk production, including cattle, goats, sheep, buffalo, and camels. Milk nutrients of interest are water/ solids, protein, fat, sugars, ash (minerals). Hence, our aim was to investigate breed and species differences in milk quality and mineral constituents from animals sampled from the same general location.

Milk samples were collected in 2021from six species/breeds in Talesh, Ardeh, Dinachal and Khaleh Sara summer villages of Guilan province, Iran. All herds were maintained in semi-open grazing systems with animals fed on natural pastures supplemented with concentrate/hay diets. Milk samples were stored at -18°C until prepared for analysis.

Colour, odour, taste, freezing point, dry matter free of fat, acidity (lactic acid), density (at 15°C), fat and protein were determined according to standard methods (AOAC, 1990). The pH was measured with a digital pH meter (microprocessor pH meter, Cyberscan, Italy 510 pH) calibrated with 4 and 8.6 buffers.

Milk samples were prepared and analyzed using inductively coupled plasma mass spectrometry (ICP-MS, 7500 Series, Agilent, Santa Clara, CA, USA) at the Aria Sharif Chemical Laboratory (Karaj, Iran). Briefly, 6 g samples of homogenous thawed milk samples were immersed in a 2:1 (v/v) mixture of 65% nitric acid (Merck, Darmstadt, Germany) at 70°C to totally dissolve the spines. The obtained solution was then mixed with distilled water in a sampling vial to a volume of 50 mL. ICP-MS was used to measure milk Ag, Al, As, B, Ba, Be, Bi, Ca, Cd, Ce, Co, Cr, Cs, Cu, Dy, Er, Eu, Fe, Ga, Gd, Ge, Hf, Hg, Ho, In, Ir, K, La, Li, Lu, Mg, Mn, Mo, Na, Nb, Nd, Ni, P, Pb, Pd, Pr, Pt, Re, Rh, Ru, Rb, S, Sb, Sc, Se, Sm, Sn, Sr, Ta, Tb, Te, Th, Ti, Tl, Tm, U, V, W, Y, Yb, Zn and Zr. A multi-element standard (1094870100SKU, Merck) was used for instrument calibration every five samples. The operational conditions for the ICP-MS were optimized following the manufacturer’s instructions (RF power 1,500 W, nebulizer gas flow rate 0.6 L min−1, plasma gas flow rate 12 L min−1, auxiliary gas flow rate 1 L min−1, integration time 6 s).

All data were examined for normality and homogeneity of variances before running the statistical analyses and transformed if necessary. The statistical analysis was performed using the two-way ANOVA (Zar, 1996) based on a completely randomized design. The statistical design was as Xij = μ + Tj + eij where Xij shows number of each control in experiment, μ was total average of society that was considered zero through samples, Tj shows effects of each group of experimental treatment and eij shows the effect of the error. The total value of any observed treatment effects, and the average test error was the result of the whole population. All statistical analyses were performed with the SPSS (1996) software package and differences of P<0.05 were considered significant.

The color, odour and taste of all milk samples was normal. The results of this study are presented in Tables I-IV. The percentage of defatted solids, acidity, density and fat of Talesh sheep’s milk was higher than the milk of other species (P<0.01). The protein concentration in Talesh sheep’s milk was higher than the milk from other species, except from Talesh buffalo milk (P<0.05). The pH of Saanen goat’s milk was higher than milk from other species, whereas the pH of sheep, goat and buffalo milk samples were higher than Mediterranean buffalo milk (P<0.01). Talesh sheep’s milk had the lowest freezing temperature (P<0.01).

Table I. Physico-chemical characteristics of first lactation milks from different ruminant species/breeds sampled in Iran (wet basis).

Means within a column with different letters are different (P<0.05).

This study showed that there were significant differences in macro and micro elements of milk from the different species. Sheep milk had the highest content of the elements Al, Ba, Ca, Co, Fe, In, La, Mg, Mn, Mo, Na, P, Pd, Pt, S, Sc, Sr and Ta (P<0.01). However, Saanen goat milk had the highest level of B, Li and Re and Talesh buffalo milk had the highest level of Cs, Se and Zn (P<0.01).

Means within a column with different letters are different (P<0.05).

Finally, a significant difference was observed in macro and micro elements of sheep milk As, Ce, He, Ir, Nb, Sb and Th (P<0.05). Although Talesh goat milk had the highest level in terms of element K, but with the amount of K milk of Talesh sheep, cows and buffaloes and Saanen goat was in the same level and there was a significant difference with the amount of K milk of Mediterranean buffalo (P<0.05). Also, Talesh goat milk had the highest amount of Rb trace element, but with Rb value of Talesh cow and buffalo milk, Mediterranean buffalo and Saanen goat were on a statistical level and there was a statistically significant difference with Rb value of sheep milk.

Buffalo milk has many advantages in terms of nutritional quality and chemical composition and is characterized by the content of fat, total solids, proteins, caseins, lactose and ash compared to cow’s milk (Bekere and Husen, 2020). In fact, various factors such as species, breed, nutritional system, lactation stage and season affect the chemical composition and nutritional qualities (Ahmad et al., 2013). However, cow’s milk has long been considered a very nutritious and valuable food for humans and is consumed in millions of dairy products (Mahmoud and Sumayra, 2010).

Salman et al. (2014) examined the difference between cow’s milk and buffalo milk in a study. The researchers said that the protein content of buffalo milk was significantly higher than cow’s milk. The protein content of Talesh buffalo milk and Talesh cow’s milk observed in the present study was consistent with the findings of Salman et al. (2014). Mahmoud and Sumayra (2010) reported more protein in buffalo milk than in cow’s milk. However, the results reported by Enb et al. (2009) did not support

Means within a row with different letters are different (P<0.05).

Means within a row with different letters are different (P<0.05).

the present findings and found less protein in buffalo and cow’s milk. The higher protein content of buffalo milk than cow’s milk may be due to the concentration of both casein and whey proteins, which has been reported to be higher in buffalo milk than in cow’s milk (Sindhu, 1998). In general, species diversity in milk protein content may be due to changes in the genetic composition of the animal (Walstra et al., 2006). In fact, it can be said that animals that grow faster (according to their size) need milk with more protein, because it provides the necessary materials for the growth of muscle tissue (Park et al., 2017).

Milk is almost an ideal food with high nutritional value. It contains proteins for body growth, minerals that make up bone and lactose and fat for energy. In addition to providing essential fatty acids, it contains nutrients in a digestible and absorbable form. Recently, the use of colostrum and adult milk derived from various mammals in human nutrition has become increasingly popular. This is mainly due to hypocholesterolemic function, better bioavailability, therapeutic properties (used in gastrointestinal disorders) and no allergies after consuming milk. Milk fat is also one of the few food sources of butyric acid and a strong inhibitor of cancer cell proliferation (Salman et al., 2014). The mineral composition of cow’s milk is 0.73 mg/l (Flynn, 1992), of which manganese is 2.89 (Belewu and Aiyegbusi, 2002), molybdenum is 0.05 (Park et al., 2017), iron is 0.81 (Anderson. 1992). Copper was 0.03 μmol/L (Licata et al., 2004), calcium was 0.58% (Hurley, 1997), and magnesium was 87 μg/ml (Fransson and Linnerdal, 1993) as 87 μg/ml (Fransson and Linnerdal, 1993).

The average lactose content in buffalo milk was relatively higher than cow’s milk. Similar findings have been reported by Park et al. (2017), who found a higher percentage of lactose in buffalo milk than in cow’s milk. The present observations are consistent with the findings of Mahmoud and Sumayra (2010), who found a similar trend for lactose content in buffalo and cow’s milk. However, the results of Bzoska et al. (2011) do not support the findings of the present study, which did not show a comparable difference between the lactose concentrations of buffalo and bovine milk. In addition, the results of the present study are not in agreement with the findings of Myburgh et al. (2012).

The use of milk and dairy products in any local area mainly follows economic factors and climatic conditions, food habits, peoples’ food tastes and the level of technology. The biological value of the proteins in milk is equal to the percentage of nitrogen absorbed, which is maintained in the body to ensure growth and survival. Milk protein contains 80% casein, 20% soluble protein. The milk composition varies not only from one species to another but also in different breeds, while environmental factors (age, season, nutrition, health, and lactation (stage and parity) in turn cause changes in milk composition (Getaneh et al., 2016).

Buffalo milk has ~5% less water than cow’s milk, thus its dry matter, protein, fat and carbohydrates are correspondingly higher than cow’s milk (Foroutan et al., 2019). The main factor in determining the energy of milk is primarily its fat content. Buffalo milk contains 97 kcal and cow’s milk has 60 kcal per 100 ml. Contrary to the misconceptions and opinions of a group of people, no credible scientific source has so far banned or restricted the consumption of buffalo milk.

Sheep and buffalo milk were higher in quality compared with goat, and cow’s milk. We suggest that a larger emphasis on sheep and buffalo milk may result in human health benefits. In general, the amount of solids in buffalo milk is about 5% more than cow’s milk, which is consistent with the results of this study, so that after Talesh sheep, the amounts of lean solids, fat and protein in Talesh buffalo milk had the highest average.

The total amount of minerals in buffalo milk is more than cow’s milk. On average, buffalo milk contains higher percentages of calcium, phosphorus, potassium, sodium, magnesium, manganese, iron and copper than cow’s milk (Singh et al., 2019) which was consistent with the results of the present study. However, it has been previously reported a lower amount of zinc in buffalo milk compared with cow’s milk, resulting in contrast with the results of the present study, so that the amount of zinc had the highest level among the milk of other species.

The worldwide production of goat’s milk is the third highest after cow and buffalo. A female goat of high-breed breeds gives an average of 3.8 liters of milk per day. Goat’s milk is similar to cow’s milk but differs from buffalo (and sheep) milk in taste, composition, type and amount of nutrients. Goat’s milk fat particles are smaller in size as well as quantity compared with buffalo milk, so goat’s milk is easier to digest and is better for children, the elderly and those with digestive disorders (Panta et al., 2021). Perhaps one of the best benefits of goat’s milk is that people who do not tolerate cow’s milk can consume goat’s milk with fewer problems (Verruck et al., 2019). Some anti-inflammatory compounds (such as polysaccharides) in goat’s milk make it easier to digest. In general, buffalo milk solids are about 4% higher than in goat’s milk, and buffalo milk is richer in protein, carbohydrates and especially fat than goat’s milk. The amount of energy in 100 ml of buffalo milk is 97 kcal, but this amount is 69 kcal in goat milk. Although the total amount of minerals in buffalo milk is less than in goat’s milk, the concentrations of Ca, Na, Mn and Cu in Iranian cow’s and goat’s milk is quite similar. Furthermore, the reported higher concentrations of P, Mg and Fe, and lower K and Zn in buffalo milk compared with goat’s milk (Chen et al., 2020) is confirmed from Iranian animals raised in the same environment in this study. So, buffalo milk is richer in most nutrients compared with cow’s milk and goat’s milk and should perhaps be considered a stronger candidate for improving health status or meeting human nutritional needs in regions of the world where they can be properly managed.

Buffalo milk is richer than cow’s and goat’s milk in terms of total solids, fat, protein, carbohydrates, calculated energy, Ca, P, Na, Mg and Fe. Goat’s milk is also richer in potassium than bovid or sheep’s milk, even among the herds sampled from the same environments in Iran.

Financial support by the Rasht Branch, Islamic Azad University, grant number [17.16.1.462] is gratefully acknowledged. The research study proposed was conducted under the grant of the RSF No. 21-16-00025, SSI NIIMMP.

The data that support the findings of this study are available on request from the corresponding author.

The authors have declared no conflict of interest.