Effect of Whey Fractions on Microbial and Physicochemical Properties of Probıotıc Ayran (Drinkable Yogurt)
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International Food Research Journal 20(3): 1409-1415 (2013) Journal homepage: http://www.ifrj.upm.edu.my Effect of whey fractions on microbial and physicochemical properties of probıotıc ayran (drinkable yogurt) 1*Ayar, A. and 2Burucu, H. 1Sakarya University, Engineering Faculty, Food Technology, Serdivan, Sakarya, Turkey 2ENKA Milk and Food Products A.Ş., Adana Çevre Yolu Sedirler Çıkışı, Konya, Türkey Article history Abstract Received: 25 May 2012 The purpose of this study was to improve the functional properties of ayran that are Received in revised form: important for nutrition of Turkish society. For this purpose, concentrated whey (normal and 6 January 2013 demineralized) and whey protein powder were added to the milk of ayran. Lactobacillus Accepted:11 January 2013 acidophilus was used as probiotic starter culture in samples. Whey concentrates significantly affected the physicochemical and probiotic properties of ayran. The dry matter, protein and ash contents in whey concentrates added ayran samples showed significant increases. Again, Keywords the amounts of mineral matter of the samples increased significantly. L. acidophilus counts in ayran samples produced with 4% normal or demineralized whey concentrates were the highest Whey ones. Lactobacillus delbrueckii subsp. bulgaricus and Streptococcus thermophilus counts in ayran probiotic treated ayran samples were also higher than that of control group. It can be said that addition of prebiotic concentrated whey and probiotic culture improved the functional properties of ayran. Produced quality ayran samples have got to probiotic and functional food properties. © All Rights Reserved Introduction probiotic strains are species specific and success in industrial applications may be obtained through The ayran is traditionally manufactured with careful management of these factors and tailored separated of fat from water-added yoghurt in churns manufacturing processes. Production of high-quality by hand. Ayran is separated from other fermented milk fermented milk products containing Bifidobacterium beverages being a yoghurt drink with salt and without spp. and L. acidophilus is, according to Gomes and any fruit flavoring. The Shelf life of ayran is reported Malcata (1999), a challenge to dairy plants owing to as 10–15 days at 4°C by the manufacturers. Ayran have the sensitive character of the microorganisms. probiotics properties, depending on the culture used Three additional components of whey have been in the production (Aysal, 2008). Probiotics, which are found to beneficially affect prebiotic formulation. The regulated as dietary supplements and foods, consist first is a protein called glycomacropeptide (GMP). of bacteria or yeast. Probiotic products may contain GMP is derived from the partial enzymatic breakdown a single microorganism or a mixture of several of kappa-casein during cheese production, becoming species. The most widely used probiotics include a component of whey. GMP has been shown to lactic acid bacteria, specifically Lactobacillus and support the growth of bifidobacteria. The second Bifidobacterium species (Williams, 2010). However, whey-derived prebiotic is lactoferrin, which has been probiotic strains may be used with a support culture, shown to support the growth of bifidobacteria and like Str. thermophilus or another yoghurt culture. Also lactobacilli. Interestingly the third whey component FAO/WHO has adopted the definition of probiotics with prebiotic potential is a mineral that is found as “Live microorganisms which when administered in high amounts within all quality whey protein in adequate amounts confer a health benefit on the formulations (Splechtna et al., 2007). host”. L. acidophilus nonpathogenic and a member As today greater attention is focused on a of the normal intestinal microflora is widely used healthy lifestyle and functional and organic food, in fermented dairy products and is of considerable the attention should be drawn to the natural whey. industrial (Deraz et al., 2007). To enrich whey and therefore increase its nutritional The probiotic product must have counts vary from value, probiotic microorganisms are one of the best 5.00 to 7.00 log CFU.g-1 of probiotic bacteria at use- choices for production of a fermented whey beverage. by date. Properties such as growth rate, metabolic rate Developing probiotic food and feed is a key research proteolytic activity and flavour promotion of several and development area for functional food markets. *Corresponding author. Email: [email protected] Tel: +9 0 26402955928 1410 Ayar, A. and Burucu, H./IFRJ 20(3):1409-1415 Considering its potential, the aim of this study Table 1. The experimental design, starter cultures and was to define the growth and survival of probiotic WC used in the manufacture of ayran samples (%) bacteria in ayran and the influence of addition of Ayran A Culture B Culture A + B Culture Group NWC DWC WP whey concentrate on it, for possible production of a Samples Group (% 4) Group (% 5) (%2+ %2) nutritive highly valuable drink. C 0 0 0 WP1 0 0 1 Material and Methods WP2 + Str. 0 0 2 delbrueckii DWC1 + 0 2 0 Material DWC2 bulgaricus bulgaricus+ Str. 0 4 0 thermophilus thermophilus L. delbrueckii subsp. bulgaricus Bulk Set FYE NWC1 2 0 0 subsp. subsp. Lactobacillus acidophilus Lactobacillus acidophilus 41 LYO 100 l, Str. thermophilus Bulk Set Y 572 NWC2 Lactobacillus Lactobacillus delbrueckii 4 0 0 C: Control, NWC: Normal Whey Concentrate, DWC: Demineralized Whey Concentrate, LYO 500 l and L. acidophilus NCFM LYO 10 DCU WP: Whey Protein (Danisco Deutschland GmbH Germany/Alemanha) cultures were originally obtained from Chr. holding capacity was determined by a procedure Hansen’s Lab (Denmark). The starter cultures were adapted from Guzman-Gonzalez et al. (1999). activated in sterile non-fat dry milk according to Mineral contents of ayran samples were determined the manufacturer’s recommendations. The cow milk as following: A 500 mg sample was weighed into used in production of ayran samples was provided crucibles, and incinerated in a microwave furnace from stockbreeding pilot management in the Animal (MARS 5, CEM Corporation) at 200oC, 170 psi for Science Department of the Agriculture Faculty of 30 min. The ashes were dissolved with a few drops Selcuk University. Whey concentrates (Normal of nitric acid (650 g.kg-1) (Sigma, USA) and diluted Whey Concentrate (NWC) and 50% Demineralized to 50 ml with deionized water. Concentrations of Whey Concentrate (DWC)), and Whey Protein minerals were quantified by ICP-Atomic Emission Powder (WP) has been provided from ENKA Dairy Spectroscopy (VARIAN-CCD Simultaneous ICP- Co., Konya, Turkey. AES, Australia) with an auto-sampling system. Aerobic mesophilic bacteria were enumerated Ayran Production on pour plates of PCA (Oxoid, Basingstoke, The formula for ayran samples are given in Table Hampshire, England) incubated at 30oC for 48-72 h. 1. The raw cow’s milk was used in the production Yeast and moulds were identified on Yeast Glucose of ayran samples. Whey fractions were added to the Chloramphenicol Agar (Oxoid) with plates incubated milk. The milk is homogenized and heated to 90°C for at 25oC for 5 days. Coliforms were identified on 10 min, and cooled to 45°C. It is then inoculated with VRB Agar (Oxoid) after incubation at 30°C for 24 40 g.kg-1 of a mixed lactic starter (Str. thermophilus h (Harrigan and Mccance, 1993). M17 agar (Difco and L. delbrueckii ssp. bulgaricus and L. acidophilus) Laboratories) was used to enumerate streptococci (Table 1). Then, samples were placed in 100 ml in ayran samples. L. acidophilus also grew on polystyrene cups and the experiment was realized in this medium; therefore, after enumeration of all triplicate. The inoculated milk was incubated at 45°C colonies on M17 agar, count of Str. thermophilus until a pH of 4.6 was attained in approximately 3.5 was determined by subtracting the count of L. h. After incubation, the ayran samples were cooled acidophilus (MRS agar with oxgall) from the total at 20°C. 20 g.kg-1 water and 4 g.kg-1 salt was added count. Plates were incubated in an aerobic incubator in ayran samples. Samples were mixed for mixing of at 37°C for 72 h. Acidified (to pH 5.2) MRS agar salt and water and were stored at 4°C temperature (Difco Laboratories) was used for enumeration of L. during all period of post-acidification (for 12 days). delbrueckii subsp. bulgaricus. Plates were incubated under anaerobic conditions at 37°C for 72 h. MRS Method agar (Difco Laboratories, Detroit, MI) with oxgall (2 Ayran samples stored at 4oC were analyzed g.kg-1) (Difco Laboratories) was used for count of L. in 1, 4, 8 and 12 days. Total solids, crude protein, acidophilus (Marshall, 1992). Plates were incubated fat, titration acidity as lactic acid and ash contents aerobically at 37°C for 72 h. of yoghurt samples were determined according to Data were statistically analyzed repeated measure the standard methods of AOAC (2005). The pH of ANOVA using SPSS for Windows 6.0. Separation of samples was measured at 6°C using a pH meter. the means (P < 0.01) was accomplished by Duncan’s Water activity (aw) of the samples was measured using multiple range test. All experiments and analyses a commercially available aw meter, measuring system were replicated three times (Minitab, 1991) (Model AQUALAB 3TE, Washington). The water Ayar, A. and Burucu, H./IFRJ 20(3):1409-1415 1411 Results and Discussion than that of the control sample (P < 0.01). In contrast to the acidity, the pH values were lower in the WC Physicochemical properties added samples. Total acidity of the samples showed The dry matter, protein, fat and ash contents of the significant increases during storage. A consistent ayran samples are presented in Figure 1. It was obvious rise in titratable acidity was observed for all the that the WC affected the chemical composition of ayran samples during storage. However, the rates the ayran samples significantly (P < 0.01).