Influence of Kombucha Inoculum on the Fatty Acid Composition of Fermented Milk Products
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TANJA Ţ: BREZO et al. / Preh. ind. – Mleko i ml. proiz. 1 (2011) 21-24 TANJA Ţ. BREZO* SNEŢANA Ţ. KRAVIĆ ZVONIMIR J. SUTUROVIĆ ANA D. KARIŠIK-ĐUROVIĆ* JASMINA S.VITAS RADOMIR V. MALBAŠA SPASENIJA D. MILANOVIĆ University of Novi Sad, Faculty of Technology, Novi Sad, Serbia *Scholar of Ministry of Education and Science of Republic of Serbia SCIENTIFIC PAPER INFLUENCE OF KOMBUCHA INOCULUM ON THE FATTY ACID COMPOSITION OF UDK: 663.88:665.12:637.146 FERMENTED MILK PRODUCTS Dairy products obtained by the fermen- INTRODUCTION portant source of essential fatty acids, tation of cow‟s milk with kombucha cultiva- especially arachidonic acid (Salamon ted on stinging nettle and peppermint tea The nutritional importance of milk et al., 2009). Additionally, milk fat is a at two different fermentation temperatures constituents places milk above other significant source of conjugated lino- were studied in order to investigate influen- ce of inoculum on fatty acid composition. nutritive substances, because it conta- leic acids (CLA), which have recently Analysis of fatty acid methyl esters was ins all of the main nutrient groups been recognised as a nutrient that performed by gas chromatography. The (Lorand, 1913). exerts important physiological effects saturated, mono and polyunsaturated fatty Milk fat is the most variable com- (Gulati et al., 2000). acid contents were within the ranges of ponent of the milk constituents (Kade- Kombucha or the tea fungus is a 62.86-70.42, 27.85-32.62 and 1.56-4.25% gowda, 2008). It is also an important symbiotic culture of acetic acid bacte- of total fatty acids, respecttively. Among all dietary source of nutrients and ener- ria and fungi capable of producing a investigated samples, milk fermented at gy, but during the past several deca- refreshing beverage with many bene- temperature of 43ºC with kombucha culti- vated on stinging nettle tea showed the des milk fat has been considered as a ficial effects on human health, by me- most desirable fatty acid composition with risk factor for coronary heart diseases ans of fermentation of sugared tea the lowest saturated fatty acid and the (CHD) and reduction in fat intake has (Dufresne and Farnworth, 2000). highest mono and polyunsaturated fatty been recommended. However, it has Black and green tea are typical sub- acid contents. been cleared that types of fat have a strates for kombucha cultivation, how- more important role in determining ever, it can be cultivated on different Key words: fatty acids • kombucha • fer- risk of CHD than total amount of fat in atypical nutrients such as coca-cola, mented milk products the diet (Hu et al., 2001). Various fatty wine, vinegar, extract of Echinacea, acids have different effects on plasma Mentha or molasses from sugar beat lipids: short and medium chain fatty processing (Malbaša et al., 2009). acids do not affect plasma lipopro- Fermentation milk products con- teins, while consumption of saturated tain all important food ingredients in fatty acids (SFA), specifically satura- such relation that a human body can ted fats with 12-16 carbon atoms tend optimally use them and because of to increase plasma total and low den- that they belong to a group of very im- sity lipoprotein (LDL) cholesterol le- portant food in human nutrition. They, vels (He et al., 2007). The fatty acid as well as milk, contain all the basic composition of milk fat typically com- ingredients needed for growth of a hu- prises 70% saturated fatty acids, 25% man body, for development, reproduc- monounsaturated fatty acids, and 5% tion, maintenance and satisfying ener- polyunsaturated fatty acids. The car- gy needs. During fermentation there is bon number of the fatty acids, their a change of some constituent of milk degree of unsaturation, and their posi- and with creating of new constituents, tional distribution within the triacylgly- fermented products get new features cerol molecules influence the nutria- compared to milk (Vitas et al., 2010). tional and physical properties and Composition of dairy products ma- consumer acceptance of foods conta- nufactured by adding pure cultures is inning milk fat (Bobe et al., 2007). Milk determined to the greatest extent by is ideal for human nutrition because of the composition of the raw milk, since high content of short chain fatty acids the cultures produce rather aroma Author address: Dr. Sneţana Kravić, Assistant, University of Novi which can be more easily attacked by materials and they affect fatty acid Sad, Faculty of Technology, Bulevar Cara Lazara the digestive enzymes. Although milk composition to a smaller extent. Kra- 1, 21000 Novi Sad, Serbia, Phone: +381 21 458 fat contains a relatively small amount vić et al. (2011) noted changes in 3662; e-mail: [email protected] of unsaturated fatty acids, it is an im- composition and contents of some 21 TANJA Ţ: BREZO et al. / Preh. ind. – Mleko i ml. proiz. 1 (2011) 21-24 fatty acid during fermentation of cow's min and then centrifuged for 10 min. tion of individual fatty acid methyl es- milk with kombucha starters cultivated The lower phase containing the lipid ters was based on relative retention on differrent inoculums, but still small fraction was isolated and evaporated times of commercial standard FAME number of researches exist about ino- to dryness under nitrogen. Mix RM-6 (Supelco) and on depen- culum effect on the fatty acid compo- dence of Kovats index of relative re- sition of kombucha fermented milk Preparation of fatty acid methyl tention times. Quantitative determina- products. Therefore, the aim of this esters tion of separated fatty acid methyl es- study was to examine fatty acid com- ters was done using method 100%. position of dairy product obtained by The methylation of fatty acid ex- addition of kombucha cultivated on tracted from milk-based kombucha RESULTS AND DISCUSSION peppermint and stinging nettle tea to products was carried out as described cow‟s milk at two different fermenta- by Kravić et al. (2010) with minor mo- Changes of pH value during tion temperatures: 40ºC and 43ºC. difications. Previously extracted fats fermentation of milk were dissolved in 2.4 cm3 of hexane. 3 -3 MATERIALS AND METHODS An aliquot (0.6 cm ) of 2 mol dm Kombucha fermentation was mo- methanolic KOH solution was added. nitored by measuring pH. Course of Inoculum The tube was capped and vigorously fermentation of milk with 1.6% milk fat shaken for 20 s and allowed to boil in the production process of kombu- Two different kombucha inocu- one min in water bath at 70°C. After 3 -3 cha fermented milk products is shown lums were prepared. The first inocu- 20s of shaking 1.2 cm of 1 mol dm in Figure 1. Samples were labelled as lum was prepared with peppermint ex- HCl was added and gently stirred. 3 following, milk fermented with kombu- tract as follows: in 1 dm of boiling tap After phase separation the upper pha- cha cultivated on peppermint tea: at a water 70 g sucrose and 2.25 g pep- se containing the fatty acid methyl temperature of 40ºC - P40 and at a permint tea (tea in bulk purchased at esters was decanted and 2 μl was temperature of 43ºC - P43; milk fer- a local health food store) was added. used for further analysis. mented with kombucha inoculum culti- After boiling for 5 minutes, the tea was cooled to room temperature, strained, 3 and then 100 cm inoculum from a 7.00 previous fermentation was added. The P40 glass jar was covered with fabric SN40 bandwidth for air. Kombucha incuba- 6.50 tion was performed at room tempe- P43 rature for 7 days. The second inocu- 6.00 SN43 lum was prepared with stinging nettle extract (tea in bulk purchased at a pH 5.50 local health food store) under the sa- me conditions as the inoculum with 5.00 peppermint extract. 4.50 Production of fermented milk 0 1 2 3 4 5 6 7 8 9 10 11 12 13 products fermentation time (h) Pasteurized and homogenized milk with 1.6% milk fat, from the pro- Figure 1. FERMENTATION PATTERN OF KOMBUCHA FERMENTED MILK ducer “AD IMLEK” Belgrade, Depart- PRODUCTS ment “Novosadska mlekara”, Novi Sad, was used for the laboratory ma- Slika 1. FERMENTACIONI DIJAGRAM PROIZVODNJE KOMBUHA nufacture of fermented milk products FERMENTISANIH PROIZVODA by adding 10% (v/v) kombucha ino- Gas chromatography analysis vated on stinging nettle tea: at tem- culum. Kombucha was added in milk perature of 40ºC – SN40 and at tem- at two different temperatures: 40ºC The analysis of fatty acid methyl perature of 43ºC – SN43. Fermen- and 43ºC, until a pH value of 4.5 was esters was performed on a Becker tation was stopped after reaching the reached. Obtained gels were cooled 409 gas chromatograph equipped pH value of 4.5. Sample P43 achieved to the temperature of 8ºC and homo- with a flame ionization detector (FID). the desired pH value for 10.10 hours, genized by mixing. Chromatographic resolution was achi- sample P40 for 11.00 hours and sam- eved using a stainless steel column (3 ples SN40 and SN43 for 11.50 hours. Lipid extraction m × 3 mm i.d.) packed with 10% SP- 2330 on 100/120 mesh Chromosorb Fatty acid composition of The extraction of fat was carried W AW (Supelco). The inlet temperatu- kombucha fermented milk products out as described by Havemose et al. re was 240ºC, and the carrier gas was (2004) with minor modifications. Fat nitrogen (99.9%) with constant flow The fatty acid composition of the was extracted from kombucha milk rate of 15 cm3 min-1. Injected sample milk and resulted four kombucha milk products (4 cm3) by adding methanol volumes were 2 µl.