Seasonal Variations in Chemical Composition of Buffalo Milk

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1 Seasonal Variations in Chemical Composition of Buffalo Milk Sarfraz AHMAD a, Tiehua ZHANG b, Frank LEE e, Yanyan LIU c, Xiaodong LI d, Mingruo GUO e* a National Institute of Food Science and Technology, University of Agriculture, Faisalabad, 38040, Pakistan, b Food College, Heilongjiang Bayi, Agricultural University, Daqing, , P.R. China c College of Quartermaster and Technology Jilin University, Changchun, , P.R. China d Northeast Agricultural University, Harbin, , P.R. China e 351 Marsh Life Science Building, University of Vermont, Burlington, VT USA *Corresponding mguo@uvm.edu ABSTRACT Buffaloes are the second most widely available milk source in the world after cow milk with ~13.0% (more than 93 out of 727 billion liters) annual production (FAOSTAT, 2011). The overall volume of buffalo milk produced can be considered twice due to higher total solids contents as compared to cow milk. Typical average milk compositions are readily available for major and minor components but information on the seasonal variations in chemical composition of buffalo milk is limited rather unavailable. Data presented in this study can be useful for the manufactures of diverse dairy products with respect to compositional variations and desired characteristics based on major components in different seasons during the whole year. Physicochemical, compositional and mineral contents of buffalo milk as a function of a one-year s cycle, were analyzed. Average contents of total solids, fat, lactose, crude protein, ash and conjugated linoleic acid in the milk were 17.2%, 7.3%, 4.6%, 5.0%, 0.91%, and 6.0 mg.g -1 fat, respectively which varied throughout the year. The average mineral contents of calcium, phosphorous, potassium, magnesium, sodium and zinc in the milk were 1799, 1217, 844, 337 and 7 mg.kg -1, respectively, and remained about steady throughout the year. The results indicated that the buffalo milk is a rich source of nutrients and are nutritionally preferable to cows milk for developing children, pregnant and lactating women as little quantity as compared to cow, goat, camel and human milk can provide recommended daily allowance of nutrients to them. Keywords: Buffalo milk, chemical composition, conjugated linoleic acid, mineral composition, physicochemical properties INTRODUCTION Globally buffalo milk production (93.02 billion liters; 12.8%) ranks second after cow milk ( billion liters, 84.4%) (FAOSTAT, 2011). In buffalo milk-producing countries (India, Pakistan and China), Buffalo milk is more preferred owing to its rich nutrition, by consumers. It is drunk as liquid or transformed into valuable products such as cheese curd locally known as dahi, yogurt and ice cream (Moio et al., 1993; Jayamanne and Adams, 2004). Buffalo milk mozzarella cheese is the most highly valued pasta filata cheese in Italy (Romano et al., 2001) and USA. Furthermore, during last few years, buffaloes as exotic animals are becoming a hope to build a market for special dairy products like cheeses due to higher yield higher nutritive values higher sensory quality and desirable textural parameters than that of cow milk (Ligda, 1996; Walstra et al., 1999). Buffalo milk contains two times higher fat contents 40 g.kg -1, 10 g.kg -1 higher caseins and ultimately higher total solids (TS) contents than that of cow milk. These attributes make it highly suitable for processing of various types of dairy products and result into whiter color, creamy textures, rich flavor and firmer texture profiles. For humans, buffalo milk is richer source of protein, fat, lactose, minerals and conjugated linoleic acid (CLA) (Khanal and Olson, 2004; Ahmad et al., 2008; Menard et al., 2010). CLA contents of animal Accepted April 10, 2013; Online February 24,

2 products like milk, meat and egg can be enhanced through animal diet (Khanal and Olson, 2004). Buffalo milk composition varies due to geographical location, breed, management practices and feeding. These compositional variations govern the changes in manufacturing conditions, nutritional properties and acceptability of products. The information on chemical composition of buffalo milk including CLA contents is available but variations due to one of major factors i.e. seasons are very limited rather unavailable. The aim of this study was to evaluate the seasonal variations over a period of one year in milk composition with particular emphasis on CLA contents and physico-chemical characteristics and mineral contents. MATERIALS AND METHODS Milk samples Bulk buffalo milk samples of three breeds (Murrah, Nili-Ravi and Jafrabadi) were collected during 2 nd week of every month from a commercial water buffalo dairy farm (Bufala di Vermont, USA) for whole year. They were fed on a mixture of baylage, corn silage and palletized supplements The samples were transported to the Analytical Foods Laboratory at the University of Vermont at 4 C. Buffalo milk samples were stored at -70 C prior to analysis of fatty acids contents. Physico-chemical, compositional and minerals analysis Chemical composition and physicochemical characteristics of milk samples was measured by using standard AOAC methods (Bradley et al., 1992). Minerals were measured according to Christie (1995). Lipid extraction, methylation, FAME and CLA analysis Lipid extraction was done according to the Mojonnier procedure in duplicate then methylation was done according to Christie (1995). A simple procedure for rapid transmethylation of glycerolipids and cholesteryl esters was followed as described by Christie (1982) and modified by Shahin et al. (2003). All Analytical grade chemicals and reagents were obtained from well-known industries like Tridecanoate and CLA isomers mixture from Matreya Pleasant Gap, PA; 0.5 N sodium methoxide in methanol and methyl acetate from SigmaAldrich Co St Louis, MO; nitrogen evaporator from Organomation Associates Inc Berlin, MA. RESULTS AND DISCUSSIONS During whole year, the minimum and maximum values found for ph: 6.76 and 6.98; fat: 6.57 and 7.97%; crude protein (CP): 4.59 and 5.37%; lactose: 4.49 and 4.73%; ash: 0.91 and 0.92% and TS: and 18.47%, respectively (see Table 1). All the readings were within normal range with data reported earlier (Ligda, 1996; Ahmad et al., 2008; Barlowska et al., 2011). However, all the values varied during the whole year showing significant impact of seasons. The highest ph value was observed in April, whereas the lowest was found in February. The lowest content of fat was observed in July during summer, whereas the highest was found in November during winter. Fat contents were higher during September to January as compared to February to August. The results of fat contents are comparable to results from a study on 7770 Nili-Ravi buffaloes in herds at the Pakistan Research Institute showing an average fat content of 6.4% (value based on 10 tests over 10 months). Regardless of season, fat content is shown to be at least 5.0% and average found higher (6.8%) than that of cow milk (3.5%) (Christie, 1982; Barlowska et al., 2011). In another study, Ligda (1996) found 77% buffaloes ranged between 5 and 8% fat and 12% buffaloes were below the 5% fat content. CP content was the highest in June during the peak of summer season and the highest was found in January during the peak of winter season. It is evident that fat and protein contents are directly proportional to each other as both were found the lowest in summer and the highest in winter. The lactose contents were the lowest in the month of April when the highest ph was observed, whereas the highest lactose contents were found in the month of February when the lowest ph was observed. So it is evident that both are inversely proportional to each other as the similar trend of increase vs. decrease was observed for other 1325

3 months for both of these parameters. Ash remained unchanged throughout the year. TS contents were the higher from November to March as compared to April to October. This study showed that buffalo milk contains 16-19% of TS as compared to12-14% for cow milk which is an important indicator for better adaptability of this milk for already existing cow milk based dairy products having better rheological characteristics. During whole year, the minimum and maximum values (mg.kg -1 ) found for Ca: 1022 and 2059; P: 707 and 1513; K: 468 and 984; Na: 235 and 462; Mg: 90 and 202 and Zn: 4 and 16, respectively (see Table 2). All these values were within the normal global averages for buffalo milk (Barlowska et al., 2011). Mineral contents of buffalo milk are higher as compared to that of cow milk except for K which found lower. Ca and P in buffalo milk are found twice the amount in buffalo milk than cow milk. Major fatty acid esters including the cis9 trans11cla isomer (the principal CLA in milk fats) are shown in Table 3. During the whole year, these fatty acids contents varied. The major saturated fatty acids were palmitic followed by stearic and myristic acids. Similar findings for buffalo milk were reported by Bergamo et al. (2003) and Menard et al. (2010). CLA have numerous benefits for human health so much interest has been given while measuring buffalo milk fat to exploit its maximum benefits for dairy product development during different seasons. During whole year, the minimum and maximum values (mg.g -1 fat) for cis9 trans11cla: 4.4 and 7.6, respectively with an average value of 5.9. Bergamo et al. (2003) reported 7.3 mg.g -1 fat of cis9trans11cla in conventional buffalo milk which is near to the maximum value found in this study, whereas Lal (1984) found 8.0 mg.g -1 fat in Asian water buffalo milk. If we observe cis9 trans11cla concentration on year round, it was found to be lower with an average value of 4.6 mg.g -1 fat during the month of July, August and September. Parodi (1977) gave reasons for the variation in CLA concentration of milk among which the season is an important one. CONCLUSIONS Buffalo breeding and milk production must be promoted due to its higher nutritional value and greater potential for processing into value added dairy products such as yoghurt, cheese, butter with desirable quality attributes. It is evident from this study that buffalo milk s physico-chemical characteristics and composition particularly CLA contents (the focused content of the study) varied as a function of seasons. Cheeses from the said milk can give better yield in winter season as compared to summer on the basis of higher TS contents. Further studies are needed to transform buffalo milk into dairy products already made by cow milk to exploit it maximally and beneficially particularly economic benefits to the consumers. REFERENCES Ahmad, S., I. Gaucher, F. Rousseau, E. Beaucher, M. Piot, J.F. Grongnet and F. Gaucheron Effects of acidification on physicochemical characteristics of buffalo milk a comparison with cow milk. Food Chem. 106: Barlowska, J., M. Szwajkowska, Z. Litwińczuk and J. Król Nutritional value and technological suitability of milk from various animal species used for dairy production. Compr. Rev. Food. Sci. F. 10: Bergamo, P., E. Fedele, L. Iannibelli and G. Marzillo Fat soluble vitamin contents and fatty acid composition in organic and conventional Italian dairy products. Food Chem. 82: Bradley, R.L., E. Arnold, D.M. Barbano, R.G. Semerad, D.E. Smith and B.K. Vines Chemical and physical methods. In: Standard methods for the examination of dairy products, 16 ed. (Marshall R. T. editor). Washington D. C. American Public Health Association Christie, W A simple procedure for rapid transmethylation of glycerolipids and cholesteryl esters. J. Lipid Res. 23:

4 Christie, W Composition and structure of milk lipids. In: Advanced dairy chemistry, 2nd ed. (Fox PF editor). London Chapman Hall 136. FAOSTAT Food and Agriculture Organization of the United Nations Available at Accessed at March 4, Jayamanne, V.S. and M.R. Adams Survival of probiotic bifidobacteria in buffalo curd and their effect on sensory properties. Int. J. Food Sci. Tech. 39: Khanal, R.C. and K.C. Olson Factors affecting conjugated linoleic acid (CLA) content in milk, meat and egg: A Review. Pak. J. Nutr. 3(2): Lal, D.M Effect of lactation number on the polyunsaturated fatty acids and oxidation stability of milk fats. India J. Dairy Sci Ligda, D The water buffalo management. Accessed at Menard, O., S. Ahmad, F. Rousseau, V. BriardBion, F. Gaucheron and C. Lopez Buffalo vs cow milk fat globules: size distribution, zeta-potential, compositions in total fatty acids and in polar lipids from the milk fat globule membrane. Food Chem. 120: Moio, L., J. Dekimpe, P.X. Etievant and F. Addeo The neutral volatile compounds of water buffalo milk. Italian J. Food Sci. 5(1): Parodi, P.W Conjugated octadecadienoic acids of milk fat. J. Dairy Sci. 60: Romano, P., A. Ricciardi, G. Salzano and G. Suzzi Yeasts from water buffalo mozzarella a traditional cheese of the Mediterranean area. Int. J. Food Microbiol. 69: Shahin, A.M., M.K. McGuire, M.A. McGuire, K.L. Ritzenthaler and T.D. Shultz Determination of c9t11cla in major human plasma lipid classes using a combination of methylating methodologies. Lipids 38(7): Walstra, P., T.J. Geurts, A. Noomen, A. Jellema and M.A.J.S. Van Boekel Dairy technology principles of milk properties and processes. In: Dairy Science and Technology. (Gustavo V. Barbosa-Cánovas et al., eds.) (2 nd ed). CRC Group, Taylor & Francis, New York. Table 1. Physicochemical characteristics and composition of buffalo milk (Mean±sd; n= 3). Months ph TS (%) Fat (%) CP (%) Lactose (%) Ash (%) Jan 6.79± ± ± ± ± ±0.01 Feb 6.76± ± ± ± ± ±0.03 Mar 6.82± ± ± ± ± ±0.01 Apr 6.98± ± ± ± ± ±0.05 May 6.88± ± ± ± ± ±0.02 Jun 6.85± ± ± ± ± ±0.03 Jul 6.82± ± ± ± ± ±0.01 Aug 6.89± ± ± ± ± ±0.04 Sep 6.91± ± ± ± ± ±0.03 Oct 6.91± ± ± ± ± ±0.01 Nov 6.78± ± ± ± ± ±0.02 Dec 6.83± ± ± ± ± ±

5 Table 2. Mineral contents of buffalo milk (mg.kg -1 ) (Mean±sd; n= 3). Month Ca P K Na Mg Zn Jan 1694±9 1217±5 835±8 419±4 150±1 7±1 Feb 1835± ±14 890±13 418±6 183±2 10±1 Mar 1505±5 1034±9 721±7 350±1 128±2 8±1 Apr 1022±14 707±17 468±10 245±4 90±1 4±1 May 2010± ±33 984±18 384±6 172±3 9±1 June 1671± ±14 759±5 267±1 135±1 16±4 Jul 2034±8 1317±4 947±7 296±1 146±1 6±1 Aug 2059±9 1243±3 920±6 235±1 137±1 5±1 Sep 1984± ±29 851±34 261±13 143±3 7±2 Oct 1974± ±8 854±18 295±12 146±1 5±1 Nov 1892± ±25 785±23 301±17 155±5 6±1 Dec 1747± ± ±31 462±15 202±7 8±1 1328

6 Table 3: Fatty Acid contents of buffalo milk mg.g -1 fat (Mean±sd; n= 2) Fatty Acid a Months 10:0 12:0 14:0 14:1 15:0 16:0 16:1 17:0 18:0 18:1 18:2 CLAb 18:3 Jan 7.5± ± ± ± ± ± ± ± ± ± ± ± ± 0.0 Feb 13.0± ± ± ± ± ± ± ± ± ± ± ± ±0.0 Mar 12.6± ± ± ± ± ± ± ± ± ± ± ± ±0.3 Apr 7.3± ± ± ± ± ± ± ± ± ± ± ± ±0.1 May 5.4± ± ± ± ± ± ± ± ± ± ± ± ±0.4 June 6.3± ± ± ± ± ± ± ± ± ± ± ± ±0.1 July 5.5± ± ± ± ± ± ± ± ± ± ± ± ±0.0 Aug 6.0± ± ± ± ± ± ± ± ± ± ± ± ±0.1 Sept 4.6± ± ± ± ± ± ± ± ± ± ± ± ±0.0 Oct 12.5± ± ± ± ± ± ± ± ± ± ± ± ±0.1 Nov 19.2± ± ± ± ± ± ± ± ± ± ± ± ±0.0 Dec 11.0± ± ± ± ± ± ± ± ± ± ± ± ±0.0 Average a Capric acid (10:0); lauric acid (12:0); myristic acid (14:0); myristoleic acid (14:1); pentadecanoic acid (15:0); palmitic acid (16:0); palmitoleic acid (16:1); margaric acid (17:0); stearic acid (18:0); oleic acid (18:1); linoleic acid (18:2); CLA (18:2) and linolenic acid (18:3) b Conjugated linoleic acid cis9 trans11cla isomer 1329