Proc. Natl. Acad. Sci., India, Sect. B Biol. Sci. DOI 10.1007/s40011-013-0208-4

RESEARCH ARTICLE

Determination of Phytochemical Contents of Avena sativa (oat) and Its Impact on Debaryomyces hansenii Pınar Erecevıt • Sevda Kırbag˘ • Fikriye Zengin

Received: 24 January 2013 / Revised: 3 June 2013 / Accepted: 19 June 2013 Ó The National Academy of Sciences, India 2013

Abstract In the present study fatty acids, vitamins, phytosterol, flavonoid and resveratrol contents and antimicrobial activities of Avena sativa (oat) extracts treated with Debaryomyces hansenii were determined and compared. Avena sativa is consumed as the fibrous food worldwide. It was shown that total fatty acids and vitamin contents increased significantly in A. sativa extracts prepared with D. hansenii. However, the flavonoid contents decreased at different rates. It was also observed that quercetin and flavonoids were present in the extracts that contained D. hansenii. It was noted that A. sativa had changing rates of antioxidants and antimicrobial activities. Thus, it was concluded that A. sativa has an important place in a healthy lifestyle and oats have positive effect on the development of D. hansenii which is also accepted as a probiotic microorganism. This yeast developed in extracts obtained from this fibrous plant and affected the bioactive compounds at changing rates. Keywords Debaryomyces hansenii  Fatty acids  Phytosterol  Vitamins  Oat

P. Erecevıt Department of the Food Processing, Tunceli Vocational School, Tunceli University, 62000 Tunceli, Turkey e-mail: [email protected] S. Kırbag˘ (&) Department of Biology, Science Faculty, Fırat University, 23119 Elazıg˘, Turkey e-mail: [email protected] F. Zengin Department of Biology, Faculty of Education, Fırat University, 23119 Elazıg˘, Turkey e-mail: [email protected]

Introduction Probiotics and prebiotics are analyzed in the functional food groups because they improve physiologic functions, showing positive impact on health, preventing diseases. Regarded as a potential probiotic yeast Debaromyces hansenii is described as one of the microorganisms in fungal microbiota which is present in kefir grains that are among the most nutritious sources of probiotics [1]. Debaryomyces hansenii, Rhodotorula glutinous, Saccharomyces cerevisiae were colonized in the intestines of rainbow trout. These highly active yeasts decrease the aerobic bacteria count [2]. It has also been shown that since these yeasts intensively adhere to the intestinal flora of fish and then colonize, they should be given more importance in future studies on probiotics [3]. With the use of prebiotics, it has become possible to treat and prevent diseases by creating a healthy environment for the host in the intestinal flora [4–6]. The regulation of human intestinal microflora with food has become a popular area of study in the food sciences [7]. This research study investigated the effects of the fibrous oat plant on the development of D. hansenii which is also accepted as a probiotic microorganism. This plant is useful health-wise and contains several phytochemical properties. The importance of this study is emphasized in the positive effects of vegetable nutrition on probiotics. These positive effects are useful for the health of living organisms.

Material and Methods The oat plant sample (A. sativa) used in this study was obtained from around Elazig Turkey. Ripe kernels were frozen at -20 °C until extracted.

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Extraction of Lipids Wet weight of cell pellets was determined and then homogenized with a 3/2 (v/v) Hexane–Isopropanol mixture. After the homogenate was centrifuged at 5,000 rpm at 4° C for 5 min, the supernatant was used for fatty acid and ADEK vitamin analysis [8]. Preparation of Fatty Acid Methyl Esters A 5 ml sample was taken from the supernatant and a 2 % methanolic sulfuric acid solution (5 ml) was added. After being vortexed, the sample was left at 50 °C for 12 h. Once cooled down to room temperature, a 5 % sodium chloride (NaCl) solution (5 ml) was added and the mixture was vortexed again. Fatty acid methyl esters were extracted with 5 ml of hexane. After this, the mixture was treated with a 2 % KHCO3 solution (5 ml), a hexane phase was evaporated with a nitrogen flow. The mixture was analyzed after it was dissolved in 1 ml of hexane. Analysis of fatty acid methyl esters was performed using a SHIMADZU GC 17 device [9, 10]. HPLC Analysis of ADEK Vitamins and Sterol Amounts A 5 % KOH solution was added to a 5 ml sample taken from the supernatant part, vortexed, and kept at 85 °C for 15 h. The mixture was then cooled to room temperature. Distilled water (5 ml) was added and then vortexed. After lipophilic molecules were treated with 2 9 5 ml of hexane, the hexane was removed. Later it was dissolved in 1 ml of (1:1, v/v) acetonitrile/methanol mixture and analyzed with a Shimadzu (brand) HPLC device [11]. Chromatograms were recorded at 320 nm for retinol (vitamin A) and retinol acetate and 215 nm for d-tocopherol, vitamin D, a-tocopherol, a -tocopherol acetate, 202 nm for phytosterols and 265 nm for vitamin K1. Identification of the individual vitamins and phytosterols was performed by frequent comparisons with authentic external standard mixtures analyzed under the same conditions [12]. The results of analyses were expressed as lg/g for each sample. Statistical Analysis SPSS 15.0 software was used for statistical analysis of the data. Analysis of variance (ANOVA) and least significant difference (LSD) tests were also used for comparisons of groups and the control group. After multiple comparisons, the means were interpreted as follows: Tables were followed with different small letters ‘‘a-cd’’ based on their values and statistical differences. The means followed with

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the same letter(s), they were not significantly different from each other. However, means with different letters were significantly different at the level of 0.05 (n = 3). DPPH Free Radical Scavenging Activity A free radical 25 mg/l DPPH (a,a-diphenyl-b-picryl-hydrazyl) methanolic solution was prepared. During this experiment plant samples at 25, 50, 100, and 250 ll concentrations were added to a DPPH radical methanolic solution (3.9 ml), vortexed, and then incubated in a dark environment at room temperature for 30 min. Absorbance values were read against a blank at 517 nm using a spectrophotometer [13, 14]. The ability to scavenge DPPH radicals was calculated by the following equation: DPPH rsa(%Þ ¼

ðAbs control  Abs sampleÞ  100 ðAbs controlÞ

(Abs control is the absorbance of DPPH radical ? methanol; the Abs sample is the absorbance of DPPH radical ? sample extract/standard). Determination of Resveratrol and Flavonoid Contents Flavonoid and resveratrol analysis was conducted on a HPLC device and all operations were performed at 25 °C [15]. Extraction and Analysis of Phytosterols KOH (5 %) was added to the plant samples which were homogenized with a hexane/isopropanol alcohol mixture (at 3/2 v/v ratio). It was hydrolyzed at 85 °C. Extraction was treated with n-heptane and analyzed with a HPLC device. Sugar Analysis A 10 g plant sample was homogenized with distilled water. The supernatant part was then separated from the pellets. After the total filtrate volume was determined, it was analyzed with a HPLC device and a Shim-Pack HRC NH2 (150 9 4.6 mm, 5 l) column was used. Acetonitrile ? water (v/v) (3:1) mixture was used as the mobile phase [16]. Antimicrobial Activity Test Microorganisms A total of 2 gram-positive bacteria (Staphylococcus aureus COWAN 1 and Bacillus megaterium DSM 32), 2 gram-

Determination of Phytochemical Contents of Avena sativa (oat) Table 1 Sugar contents of A. sativa (oat) extract Sugars

Arabinose

Fructose

Glucose

Saccharose

Maltose

O

0.0027 ± 0.0001

0.038 ± 0.00001cd

0.062 ± 0.0001cd

0.0003 ± 0.00001

0.0131 ± 0.0001d

O: A. sativa (oat), cd: p \ 0.0001, d: p \ 0.001

negative bacteria (Escherichia coli ATCC 25922 and Klebsiella pneumoniae FMC 5), 2 yeasts (Candida albicans FMC 17 and Candida glabrata ATCC 66032) and 2 dermatophyte species (Trichophyton sp. and Epidermophyton sp.) were used in this research. Microorganisms were provided by the Department of Biology, Firat University Microbiology Lab, Elazig, Turkey.

development had stopped and pellets were collected. Fatty acid, vitamin, flavonoid, and resveratrol levels and antimicrobial activities of these pellets were analyzed. As a control group, the same operations were applied on D. hansenii and corn developed only in minimal wells, and then comparisons were made. This study was performed using three parallel experiments.

Antimicrobial Tests Results and Discussion Antimicrobial tests were carried out by the well agar method using 100 ll of a suspension containing 106 cells/ml of bacteria, 104 cells/ml yeast and cells/ml dermatophyte fungi as per the McFarland standard. The samples were inoculated into Mueller–Hinton Agar (Difco), Malt Extract Agar (Difco), and Sabouroud Dextrose Agar (Oxoid), respectively. Wells were prepared in the plates with the help of cork-borer (0. 85 cm). 10 ll of the flavonoids, vitamins and fatty acids were introduced directly into the well. Sterilized petri dishes (9 cm diameter) were placed at 4°C for 2 h. The inoculated plates were incubated at 37 ± 0.1°C at 24 h for bacterial strains and also at 25 ± 0.1°C at 72 h for yeast and dermatophyte fungi. At the end of the incubation period, the inhibition zones were measured as millimeters. Antimicrobial activity was evaluated by measuring the zone of inhibition against the test organisms [17, 18]. Wells injected with methanol and hexane served as negative controls. The experimental studies were replicated three times. Development of Debaryomyces hansenii and its Treatment with Avena sativa (oat) Extract Debaryomyces hansenii was cultivated in Yeast Malt Extract Bouillon for its development and reproduction. After absorbance values were read (517 nm) using a spectrophotometer, A S. boulardii (1 %) culture in bouillon (104 yeast/ml) was inoculated into prepared minimal well (0.019 M NaCl, 0.022 M KH2PO4, 0.049 M Na2HPO4, 0.019 M NH4Cl, 0.002 M MgSO4, 0.011 M Glucose) [19] with oat extract under sterilized conditions and an appropriate pH level (4.8) was maintained. Extracts developed in the minimal well were collected for a living cell count after they were read at 6, 12, 24, 36, 48, 60, and at 72 h at 517 nm on the spectrophotometer. The samples were then cultivated in Malt Extract Agar and incubated. Colony counts were examined. Samples were centrifuged when

Sugar Contents When sugar analysis of plant extracts was examined (Table 1), it was observed that fructose, glucose and maltose contents in A. sativa extract were at significant levels (p \ 0.0001, p \ 0.001). Fatty acids, Lipide-Soluble Vitamins and Sterol Contents Fatty acids Upon the fatty acid analysis of A. sativa extracts (Table 2), it was observed that palmitic acid (16:0), stearic acid (18:0), oleic acid (18:1n9), linoleic acid (18:2) and linolenic acid (18:3) were present and contained 16:0 and 18:2 at high levels (p \ 0.0001). It was detected that 16:0, 16:1, 18:0, 18:1, 18:2, 18:3 levels in the A. sativa extracts treated with D. hansenii had significantly increased when compared to the oat control group and D. hansenii (cd: p \ 0.0001, d: p \ 0.001). The increase in fatty acid level indicates that D. hansenii, which is accepted to be a probiotic, symbiotically exists with A. sativa extract and were being affected by the carbon source in the medium. This carbon source activates the enzymes responsible for fatty acid synthesis. Based on the increase in fatty acid content, this kind of environment encourages the development of D. hansenii. It is concluded that supporting the development of D. hansenii, as this medium exhibited, increase in fatty acid content. Lipid-Soluble Vitamins and Sterol Contents Upon the analysis of A. sativa extracts in relation to their vitamin and phytosterol contents (Table 3), it was detected that K1, K2, D vitamins d-tocopherol a-tocopherol, retinol,

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retinol acetate, phytosterols; ergosterol, stigmasterol, b-sitosterol were present. When compared to the control group, it was detected that in A. sativa extracts treated with D. hansenii, K1, D vitamins, d-tocopherol, retinol and retinol acetate amounts increased to high level (p \ 0.001), a-tocopherol and ergosterol amount increased to significantly high level (p \ 0.0001) while K2, stigmasterol amount decreased. It is thought that the decrease in the level of vitamins is due to the consumption by the yeast and the increase in the values of other vitamins is based on D. hansenii. Based on these results, it was determined that A. sativa has a positive impact on D. hansenii development. According to this finding it is suggested that the increase is caused by vitamin and phytosterol production as the result of A. sativa extract’s positive effect on the development of D. hansenii.

Table 2 Fatty acid levels of A. sativa (oat) treated with D. hansenii (lg/g). Values with different small letters in the same row are significantly different at the level of 0.05 (p \ 0.05) O

O ? DH

O cd

16:0

779.33 ± 1.64

d

DH

217.06 ± 0.033

16:1

333.43 ± 1.71

18:0 18:1

128.53 ± 3.48d 2295.43 ± 7.73cd

34.60 ± 0.05 147.46 ± 0.08

18:2

3920.30 ± 46.25cd

585.06 ± 0.06

18:3

111.00 ± 11.82d

42.10 ± 0.06

–

48.68 ± 0.35 – 29.50 ± 0.34 54.36 ± 0.38 68.70 ± 0.55

Flavonoid Contents and Radical Scavenging Properties Rutin, morin, kaempferol, catechin, naringin, naringenin were present in the oats but the amount of catechin and naringenin in this plant was higher than other phenolic compounds. However, resveratrol was absent (Table 4). All present flavonoid compounds except quercetin (p \ 0.01) decreased in the A. sativa extract treated with D. hansenii at different levels with respect to the control oat plant (p \ 0.0001, p \ 0.001, p \ 0.01, p \ 0.05), but there was no difference in terms of the amount of myricetin (p [ 0.05). Thus, increasing amount of quercetin at very low levels (p \ 0.05) in the A. sativa extract treated with D. hansenii indicated that D. hansenii made this Table 4 Flavonoid and resveratrol levels of A. sativa (oat) treated with D. hansenii (lg/g) Flavonoids

O ? DH c

Rutin

–

Myricetin

–a c

O 0.0004 ± 0.00001 –

Morin

–

Quercetin

0.0001 ± 0.00001b

–

Kaempferol

–b

0.0001 ± 0.00001

Catechin

0.0006 ± 0.00001c

0.0014 ± 0.00001

Naringin Naringenin

–cd –d

0.0060 ± 0.0006 0.0013 ± 0.0004

0.0006 ± 0.00006

Notes Values are expressed as mean ± standard deviation of three replicate analyses. The values in the same column were not significantly different (p [ 0.05)

Each value is expressed as mean ± standard deviation of three replicates. Values with different small letters in the same column are significantly different at the level of 0.05 (p \ 0.05). The values in the same column were not significantly different (p [ 0.05). In A. sativa (oat) treated with D. hansenii when compared to the control group; A. sativa (oat) extracts

O: A. sativa (oat), DH: D. hansenii, O ? DH: Oat ? D. hansenii, cd: p \ 0.0001, d: p \ 0.001, (–): not detected

O: A. sativa (oat), DH: D. hansenii, O ? DH: Oat ? D. hansenii, cd: p \ 0.0001, d: p \ 0.001, c: p \ 0.01, b: p \ 0.05, a: p [ 0.05

Total lg/1 g 7687.63 ± 77.24cd 1026.30 ± 0.17

– 201.25 ± 1.54

Table 3 Phytosterol and vitamin levels of A. sativa (oat) treated with D. hansenii (lg/g) Lipophilic vitamins and phytosterols Vitamin K1 Vitamin K2 Vitamin D

O ? DH 0.043 ± 0.003d c

0.0022 ± 0.00

0.011 ± 0.0001d cd

DH

O

0.0018 ± 0.0001

0.0015 ± 0.0001

0.0031 ± 0.00

0.0009 ± 0.0001

0.0011 ± 0.0001

0.007 ± 0.002

a-tocopherol

0.20 ± 0.0003

d-tocopherol

0.049 ± 0.003d

0.0001 ± 0.00

0.0018 ± 0.0001

0.0018 ± 0.0001d

0.0002 ± 0.00

0.0003 ± 0.00

0.0001 ± 0.00 0.008 ± 0.00028

0.0001 ± 0.001 0.12 ± 0.01

Retinol Retinol acetate b-sitosterol Stigmasterol Ergosterol

d

0.0011 ± 0.00 0.19 ± 0.004b 0.036 ± 0.0003c 0.32 ± 0.017

cd

0.0070 ± 0.00056

0.020 ± 0.0009 0.0021 ± 0.01

0.015 ± 0.013

0.099 ± 0.025 0.0073 ± 0.001

Each value is expressed as mean ± standard deviation of three replicates. Values with different small letters in the same column are significantly different at the level of 0.05 (p \ 0.05) O: A. sativa (oat), DH: D. hansenii, O ? DH: Oat ? D. hansenii, cd: p \ 0.0001, d: p \ 0.001, c: p \ 0.01, b: p \ 0.05

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Determination of Phytochemical Contents of Avena sativa (oat)

and C. glabrata (16.0, 32.5 and 17.5 mm, respectively). It was also shown that the A. sativa fatty acid extract did not have any effect on E. coli, S. aureus and Epidermophyton sp. The A. sativa fatty acid extract prepared with D. hansenii inhibited the rate of growth of microorganisms at a very low rate as in: E. coli and K. pneumoniae (8.33–9.66 mm/inhibition zone) but they did not affect other bacteria types. It was also detected that there was a very high antifungal activity against C. albicans (24.66 mm), C. glabrata (22.6 mm), Epidermophyton sp. (18.66 mm) and Trichophyton sp. (26.6 mm). Moreover, D. hansenii fatty acid extracts specifically inhibited the growth of yeast and dermatophyte fungi (C. albicans; 11.33, Epidermophyton sp.; 21.00 mm) (Table 6, 7). They were also effective against S. aureus (12.00 mm) and E. coli (12.00 mm) as well.

flavonoid at trace level only. When compared to the A. Sativa control group, the decrease in other phenolic compounds (rutin, morin, kaempferol, catechin, naringin, naringenin) indicated that D. hansenii uses these compounds in A. sativa. When the DPPH (a,a-diphenyl-bpicrylhydrazyl) free radical scavenging effect of A. sativa was analyzed, it showed antioxidant activity at a concentration of 100 ll (Fig. 1). Antimicrobial Activity Antibacterial and antifungal effects of fatty acid extracts of A. sativa plant are given in Table 5. These extracts inhibited the developments of bacteria, yeast and dermatophyte fungi excluding E. coli, S. aureus and Epidermophyton sp. (at different rates). It was also observed that these extracts had high level of antimicrobial activity against C. albicans and Trichophyton sp. (15.5 mm) and still higher levels against K. pneumoniae, B. megaterium

Table 6 Antimicrobial activities of fatty acid, vitamin and flavonoid extracts of A. sativa (Oat) (mm) treated with D. hansenii (lg/g) Microorganisms

Inhibition zones (mm) Fatty acid

E. coli K. pneumoniae

Vitamin

Flavonoid

8.33 ± 0.33

–a

–a

9.66 ± 0.33

a

–

8.50 ± 0.33

B. megaterium S. aureus

–a –a

C. albicans

24.66 ± 0.33

cd

14.00 ± 0.33

22.66 ± 0.33

cd

9.66 ± 0.33

Epidermophyton sp. 18.66 ± 0.33

cd

18.00 ± 0.33

Trichophyton sp.

cd

9.66 ± 0.33

C. glabrata

–a 15.00 ± 0.33

26.66 ± 0.33

cd cd

–a –a –a –a

cd

–a –a

Each value is expressed as mean ± standard deviation of three replicates. Values with different small letters in the same column are significantly different at the level of 0.05 (p \ 0.05)

Fig. 1 DPPH radical scavenging activity of A. sativa (Oat) extract. A lower concentration was used for DPPH radical scavenging activity test to obtain a more accurate analysis

(–) not detected

Table 5 Antimicrobial activities of fatty acid, vitamin and flavonoid extracts of Avena sativa (Oat) (mm) Microorganisms

A. sativa (Oat) inhibition zones (mm) Fatty acid

E. coli K. pneumoniae

–a 16.66 ± 1.00

B. megaterium

32.50 ± 2.50

Vitamin

cd cd

a

S. aureus

–

C. albicans

15.50 ± 0.50d

C. glabrata

17.50 ± 0.50

Epidermophyton sp. Trichophyton sp.

36.00 ± 0.57 34.00 ± 0.57

cd

22.66 ± 0.33d 34.00 ± 1.00

cd

cd

cd

18.66 ± 0.57d

Control inhibition zones (mm) Flavonoid

Methanol

Hexane

Standart antibiotics

–a –a

– –

15.4 ± 0.2 14.5 ± 0.3

10.3 ± 0.3** 9.5 ± 0.3**

–

13.3 ± 0.4

13.4 ± 0.1**

–

12.4 ± 0.1

9.4 ± 0.3**

–

17.2 ± 0.1

18.2 ± 0.2* 12.6 ± 0.4*

16.33 ± 1.0 –

cd

a

12.33 ± 2.0

cd

36.00 ± 0.57

cd

8.66 ± 0.33b

–

11.1 ± 0.2

–a

29.00 ± 0.33

cd

8.66 ± 0.33b

–

9.3 ± 0.3

NT

15.50 ± 0.50d

25.00 ± 0.33

cd

8.66 ± 0.33b

–

17.4 ± 0.4

NT

Each value is expressed as mean ± standard deviationof three replicates Values with different small letters in the same column are significantly different at the level of 0.05 (p \ 0.05) the inhibition zones were measured as mm *: Nystatin (Antifungal, 30 lg/disc), **: Streptomysin su¨lfat (antibacterial,10 lg/disc), Control (methanol and hexzane):10 lL, NT: not tested, (–): not detected

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P. Erecevıt et al. Table 7 Antimicrobial activities of fatty acid, vitamin extracts of D. hansenii (mm) Microorganisms

Fatty acid

E. coli

12.00 ± 0.57

K. pneumoniae B. megaterium S. aureus C. albicans C. glabrata Epidermophyton sp. Trichophyton sp.

–

a

–

a

Vitamin cd

8.33 ± 0.33ab 9.66 ± 0.33b 9.66 ± 0.33b

12.00 ± 0.57

cd

d

11.33 ± 0.57

13.66 ± 0.33

cd

b

9.66 ± 0.33

8.33 ± 0.57a

9.66 ± 0.33b

21.00 ± 0.57 cd 10.66 ± 0.66d

15.66 ± 0.33 cd 11.66 ± 0.33d

(–): not detected, cd: p \ 0.0001, d: p \ 0.001, b: p \ 0.05 a: p [ 0.05

Upon the analysis of vitamin extracts in A. sativa on the development of bacteria, yeast and dermatophyte fungi, it showed significant antimicrobial activity against E. coli (36.0 mm), K. pneumoniae (34.0 mm), B. megaterium (22.66 mm), C. albicans (18.66 mm), C. glabrata (36.0 mm), Epidermophyton sp. (29.0 mm) and Trichophyton sp. (25.0 mm). Vitamin extracts containing D. hansenii prepared from A. sativa had an effect on S. aureus; however, they did not affect other bacterial types, they were very effective against all yeast and dermatophyte fungi as C. glabrata (9.66 mm), Trichophyton sp. (9.66 mm), especially C. albicans (13.66 mm/inhibition zone) and Epidermophyton sp. (17.66 mm). D. hansenii vitamin extracts were also effective at changing rates against all of the bacteria, yeasts and dermatophyte fungi (8.33–15.66 mm). The flavonoid extracts of A. sativa were analyzed in terms of their antibacterial and antifungal activities. These extracts had very little effect against microorganisms such as C. glabrata, Epidermophyton sp. and Trichophyton sp. (8.66 mm/inhibition zone). The extracts had significant antibacterial and antifungal activity over B. megaterium (16.33 mm) and C. albicans (12.33 mm). The A. sativa flavonoid extracts did not have any effect on K. Pneumoniae and S. aureus. The A. sativa flavonoid extracts prepared with D. hansenii did not have any effect on any of the microorganisms (Table 6). Thus, the data supported results of flavonoid analyses of oats prepared with D. hansenii. The reason for this reduction is related to the consumption of these bioactive compounds by D. hansenii which produces antimicrobial activity. Earlier researchers also reported that sensitivity of microorganisms against chemotherapeutic materials differs from strain to strain [20] whereas phytochemical characteristics of plants differ from type to type [21], hence some plant extracts may demonstrate antimicrobial activities. This assertion supports the findings of this study. In the present study, when antimicrobial activities of A. sativa extracts containing D. hansenii were analyzed, it

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was observed that they had a significant effect (at changing rates) against some of the bacteria and all of the yeasts and dermatophyte fungi with respect to the control groups of fatty acids and vitamin extracts. This assertion supports the findings of this study. Accordingly, it has become evident that the data presented parallel results with fatty acid, vitamin, phytosterol, flavonoid, and resveratrol analyses. The data obtained recently draw attention to the issue of the increasing frequency of chronic diseases with the transition from natural and unprocessed food to processed food which often has higher energy. There is a clear interaction with the increase of chronic diseases and the decrease in consumption of plant-derived fibers and antioxidants [22]. Previous studies have suggested that natural pre-probiotics should be included in the diet for a healthier life [23]. Some peptides and proteins are prebiotic but generally fibrous foods are emphasized as good sources of prebiotics. Oats, wheat bran, fruits, vegetables and legumes are fiber-rich food that are important for a healthy life. Consuming fibrous food and other useful nutrients such as vitamins, minerals and phenolic compounds make them superior to dietary fiber tablets or support products [24]. Oats have more soluble fibers than wheat, barley, rice or corn. These soluble fibers are generally found in a b-glucan structure. b-glucan has been proved to have a positive impact on health. It has been confirmed that b-glucan is a good prebiotic for the accretion of useful lactic acid and the reproduction of bifidobacteria in the large intestine. Thus, nutritional experts recommend people to consume food that includes components with important functions in mechanisms that regulate metabolism [24]. Oats have an important role in animal feed and has gained more importance today as a raw material for human nutrition also [25]. Earlier studies reported that the linolenic acid (18:3) level in the oat significantly increased by decreasing temperature [26]. Oleic, linoleic and palmitic acids are present in this plant species and the total fatty acid content is higher than 95 %. These findings are in agreement with the results of this study [27]. It was also reported that oats included many bioactive compounds as vitamin E, tocols, phytic acid, phenolic component, flavonoid and phytosterols and demonstrated antioxidant activity [28]. Avena sativa is a fibrous plant important for nutrition of all living creatures. Although studies have been conducted about bioactive compounds in oats and their impact, no study was reported in past literature about the effect of this fibrous food on the development of one of the probiotic yeasts such as D. hansenii or about the determination of its effects on this specific yeast. Studies in regard to the phytochemical composition and antioxidant activities of some plants have not been noted [29, 30]. This study will be beneficial in observing the effects of probiotic yeasts in the food of plant origin.

Determination of Phytochemical Contents of Avena sativa (oat)

Conclusion In light of the data obtained, it was discovered that the A. sativa plant has positive effects on the development of D. hansenii which is accepted to be a useful probiotic yeast and that D. hansenii developed inside the extracts obtained from this plant affected active biological compounds at various changing rates. The importance of this study was validated in terms of the positive impact of fiber-rich vegetable nutrition on probiotics (plant-probiotic relationship) which are both healthy and useful for all living creatures.

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