Chemical Composition and Sensory Analysis of Cheese Wheybased Beverages Using Kefir Grains As Starter Culture
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View metadata, citation and similar papers at core.ac.uk brought to you by CORE provided by Universidade do Minho: RepositoriUM International Journal of Food Science and Technology 2011, 46, 871–878 871 Original article Chemical composition and sensory analysis of cheese whey-based beverages using kefir grains as starter culture Karina Teixeira Magalha˜es,1,2 Disney Ribeiro Dias,3 Gilberto Vinicius de Melo Pereira,1 Jose´ Maria Oliveira,2 Lucı´lia Domingues,2 Jose´ Anto´nio Teixeira,2 Joa˜o Batista de Almeida e Silva4 & Rosane Freitas Schwan1* 1 Department of Biology, Federal University of Lavras (UFLA), Campus Universita´rio, 37.200-000, Lavras, MG, Brazil 2 IBB – Institute for Biotechnology and Bioengineering, Centre of Biological Engineering, Universidade do Minho, Campus de Gualtar, 4710-057, Braga, Portugal 3 Department of Food Science, Federal University of Lavras (UFLA), 37.200-000, Lavras, MG, Brazil 4 Department of Biotechnology, Engineering School of Lorena, University of Sa˜ o Paulo (USP), 12.602-810, Lorena, SP, Brazil (Received 12 August 2010; Accepted in revised form 9 January 2011) Summary The aim of the present work was to evaluate the use of the kefir grains as a starter culture for tradicional milk kefir beverage and for cheese whey-based beverages production. Fermentation was performed by inoculating kefir grains in milk (ML), cheese whey (CW) and deproteinised cheese whey (DCW). Erlenmeyers containing kefir grains and different substrates were statically incubated for 72 h at 25 °C. Lactose, ethanol, lactic acid, acetic acid, acetaldehyde, ethyl acetate, isoamyl alcohol, isobutanol, 1-propanol, isopentyl alcohol and 1-hexanol were identified and quantified by high-performance liquid chromatography and GC-FID. The results showed that kefir grains were able to utilise lactose in 60 h from ML and 72 h from CW and DCW and ) ) ) produce similar amounts of ethanol (12 g L 1), lactic acid (6gL 1) and acetic acid (1.5 g L 1) to those obtained during milk fermentation. Based on the chemical characteristics and acceptance in the sensory analysis, the kefir grains showed potential to be used for developing cheese whey-based beverages. Keywords Cheese whey beverage, GC-FID, HPLC, kefir, lactic acid bacteria, sensory evaluation, yeasts. (LAB) including Lactobacillus, Lactococcus, Leuconos- Introduction toc and Streptococcus spp. and yeasts (Kluyveromyces, Cheese whey (CW) is the major by-product of the dairy Torula, Candida and Saccharomyces spp.). Both the industry and its disposal without expensive sewage bacteria and yeast are surrounded by a polysaccharide treatments represents a major source of environmental matrix, called kefiran, which is a water-soluble branched pollution. Considerable efforts have been made over the glucogalactan (Magalha˜ es et al., 2010b). past years to explore new outlets for CW utilisation and The production of a functional beverage produced reduce environmental pollution (Magalha˜ es et al., upon whey fermentation by kefir grains could be an 2010a). Besides potable ethanol production by lactose interesting alternative for CW utilisation. CW fermenta- converting microorganisms (Guimara˜ es et al., 2010) and tion by kefir microrganisms could decrease the high the production of distilled beverages (Dragone et al., lactose content in CW, producing mainly lactic acid and 2009) and kefir-like CW beverages (Magalha˜ es et al., other metabolites such as aroma compounds contributing 2010a) this by-product has also been suggested as an to the flavour and texture and increasing carbohydrate alternative for industrial residue utilisation which may solubility and sweetness of the end product. Manufacture reduce environmental pollution. of beverages through lactic fermentations can provide Traditionally kefir grains have been used in many desirable sensory profiles and have already been consid- countries, especially Eastern Europe, as a natural starter ered an option to add value to CW (Pescuma et al., 2008). in the production of kefir, a unique self-carbonated Recently, Magalha˜ es et al. (2010a) set out to cha- dairy beverage. Kefir differs from other fermented milks racterise kefir-associated microbiota by using two unre- in its starter, which exists in the form of grains (Simova lated techniques, DNA analysis [by denaturing gradient et al., 2002). Kefir grains contain lactic acid bacteria gel electrophoresis (DGGE)] and optical microscopy (combining fluorescence staining with confocal laser *Correspondent: Fax: +55 35 38291100; microscopy). The composition of microbiota was related e-mail: [email protected]fla.br to Lactobacillus kefiranofaciens subsp. kefirgranum, doi:10.1111/j.1365-2621.2011.02570.x Ó 2011 The Authors. International Journal of Food Science and Technology Ó 2011 Institute of Food Science and Technology 872 Chemical and sensory analysis of CW-based kefir beverages K. T. Magalha˜ es et al. Lactobacillus kefiranofaciens subsp. kefiranofaciens,an 2-methyl-1-propanol, 2-methyl-1-butanol, 3-methyl-1- uncultured bacterium related to the genus Lactobacillus, butanol were purchased from Fluka Analyticals (Seelze, Kluyveromyces marxianus, Saccharomyces cerevisiae and Germany). Ethyl acetate, Acetaldeyde lactose, were Kazachstania unispora. No differences were found in the purchased from Sigma-Aldrich (St Louis, MO, USA) community structure detected in the analysed beverage and acetic acid, lactic acid, ethanol, methanol were and Brazilian kefir grains, showing that microbiota of purchased from Merck (Darmstadt, Germany). kefir grains is highly stable along the fermentations carried out in different substratum. However, this Organic acids, sugars and ethanol characterisation was restricted to the microbiota and until Lactose and ethanol were quantified by high-perfor- recently, we were not aware of any reports concerning mance liquid chromatography (HPLC), using a Jasco the chemical and sensorial characterisation of these chromatograph equipped with a refractive index (RI) beverages. Therefore, the aim of the present work was to detector (Jasco 830-RI, Madrid, Spain). Lactic acid and evaluate the use of the kefir grains as a starter culture for acetic acid were also quantified by HPLC, using a Jasco traditional milk kefir beverage and for CW-based chromatograph equipped with UV–Visible detector beverages production, besides evaluating the biochem- (Jasco 870-UV-visible). A Chrompack column (300 · ical changes, organic acids production and volatile 6.5 mm) at 60 °C, using 5 mM sulphuric acid as the compounds formation during fermentation process. eluent, at a flow rate of 0.5 mL min)1 and a sample volume of 20 lL was used. Materials and methods Volatile flavour substances In order to identify the volatile compounds, the kefir CW-based and milk fermentation media beverages were analysed directly without any previous Three different substrates containing lactose concentra- treatment according to Fraile et al. (2000). A Chrompack ) tion of 46 g L 1 were used as fermentation media: CP-9000 gas chromatograph equipped with a Split ⁄ Split- pasteurised full cows milk (ML), CW and deproteinised less injector, a flame ionisation detector, and a capillary cheese whey (DCW). CW powder, obtained from a column (50 m · 0.25 mm i.d., 0.2 lm film thickness; regional dairy industry (Lactogal, Porto, Portugal), was Chrompack) coated with CP-Wax 57 CB was used. The dissolved in sterile distilled water until the desired temperature of the injector and detector was set to 250°C. lactose concentration. DCW was made by autoclaving The oven temperature was held at 50°C for 5 min, then ) at 115 °C for 10 min the CW solution, followed by programmed to run from 50°C to 220°Cat3°C min 1 and aseptic centrifugation (2220 g for 20 min) to remove then held at 220°C for 10 min. Helium was used as the cream. Confirmation of CW deproteinisation was carrier gas at 125 kPa, with a split vent of 15 mL min)1. accomplished for Kjeldahl method. Injections of 1 lL were made in the splitless mode (vent time, 15 s); 4-nonanol (internal standard) was added to the sample to a final concentration of 122.05 mg L)1. The Kefir beverages production volatile compounds were identified by comparing the Brazilian kefir grains were employed in the present retention times of the samples with those of standard study. The grains (12.5 g) were washed with sterile compounds. Quantification of volatile compounds was distilled water and inoculated in 250 mL of ML, CW performed with Varian Star Chromatography Worksta- and DCW. The milk is used commonly for kefir tion software (Version 6.41) and expressed as 4-nonanol beverage, therefore was used to compare the fermenta- equivalents, after determining the detector response tion with CW kefir beverages. Erlenmeyers containing factor for each compound. kefir grains were statically incubated for 72 h at 25 °C. Samples of the kefir beverages were aseptically taken Sensory evaluation every 12 h for analysis of organic acids, ethanol, sugars The final kefir beverages (ML, CW and DCW) were and volatile flavour substances. Determination of total evaluated by twenty-five untrained tasters, males and reducing sugars was used to assess the substrate females, 25–35 years of age (students of the Centre of consumption. The pH of the fermented beverages was Biological Engineering, University of Minho, Campus measured using a Micronal B474 pH meter. Two Gualtar, Braga, Portugal). Randomised, refrigerated replicates were done in each fermentation batch. (10 °C) samples of 10 mL were served (containing 1.0 mg of sucrose) in clear, tulip-shaped glasses with a volume of 50 mL; these were marked with three digit Analytical methods random numbers and covered with Petri dishes. Dis- Chemicals tilled water was provided for rinsing of the palate during 1-Hexanol and ethyl acetate were purchased from the testing. Tasters were asked to indicate how much Aldrich Chemistry (Munich, Germany). 1-propanol, they liked or disliked each product on a 9-point hedonic International Journal of Food Science and Technology 2011 Ó 2011 The Authors International Journal of Food Science and Technology Ó 2011 Institute of Food Science and Technology Chemical and sensory analysis of CW-based kefir beverages K.