ArticlePDF Available

Response Surface Methodology for Optimization of Glucuronic Acid Production Using Kombucha Layer on Sour Cherry Juice

Authors:

Abstract and Figures

The optimum conditions for the glucuronic acid production (the important key component for its detoxifying action through conjugation to the xenobiotic metabolism of the substances in liver) using kombucha layer on sweetened sour cherry juice were determined using response surface methodology. Kombucha layer involving a symbiosis of osmophilic yeast species and acetic acid bacteria that convert a very simple substrate to a slightly carbonated, acidic, refreshing beverage with high pharmaceutical and nutritional value. A central composite rotatable design, consisting of seventeen experiments was used to investigate the effects of three independent variables, namely sucrose content, temperature and the cultivation time on five responses: glucuronic acid (g/L), pH value, remained sucrose (g/L), reducing sugar (g/L), and total acidity (g/L). Statistical analysis of the obtained results, depicted that all the factors had a significant effect which leads to glucuronic acid concentration upto maximum 132.5 g/L at 37 °C within two weeks of fermentation process on 8% sucrose-sweetened sour cherry juice.
Content may be subject to copyright.
Journal of Food Research; Vol. 7, No. 1; 2018
ISSN 1927-0887 E-ISSN 1927-0895
Published by Canadian Center of Science and Education
61
Glucuronic Acid Rich Kombucha-fermented Pomegranate Juice
Nafiseh Yavari1, 2, Mahnaz Mazaheri-Assadi2, Ziauddin H. Mazhari1, Mohammad B. Moghadam3 & Kambiz
Larijani4
1Department of Bioresource Engineering, McGill University, Macdonald Campus, Macdonald-Stewart Building,
21,111 Lakeshore Rd., Ste. Anne de Bellevue, QC, H9X 3V9, Canada
2Biotechnology Department, Iranian Research Organization for Science and Technology, Tehran, Iran
3College of Economics, Allameh Tabataba‘i University, Tehran, Iran
4Laboratory Complex, Islamic Azad University, Science and Research Branch, Tehran, Iran
Correspondence: Dr. Mahnaz Mazaheri-Assadi, Biotechnology Department, Iranian Research Organization for
Science and Technology, Tehran, Iran. Tel: 98-21-8883-8350. E-mail: mxmazaheriassadi@yahoo.com
Received: November 19, 2017 Accepted: December 5, 2017 Online Published: December 24, 2017
doi:10.5539/jfr.v7n1p61 URL: https://doi.org/10.5539/jfr.v7n1p61
Abstract
This study is the first report using tea fungus ―kombucha‖ to ferment natural pomegranate juice to produce a
fermented beverage with high content of glucuronic acid, as a human health beneficial component. We profited
the acetic acid bacteria and yeasts symbiotic layer, which is well known in producing pharmaceutical beverages
with considerable released organic acids such as glucuronic acid. Also, we used the natural pomegranate juice
with high amount of carbohydrate and acid, as a favourable substrate for the fermentation process. The yield of
glucuronic acid production was monitored by cultivating natural pomegranate juices under the 17
optimized-combinations of three distinct sucrose concentrations, fermentation temperatures, and processing time.
The combinations were designated by applying the statistical response surface methodology method. The
maximum amount of glucuronic acid 17.074g/l determined in the media with 8g/l supplementary sucrose after
14 days fermentation at 37°C, using high-performance liquid chromatography. Along with glucuronic acid
production, effect of the three factors - sugar concentration, processing temperature and time - was also
examined on changes of five physical and chemical properties of the fermented pomegranate juices, including;
pH value, remained sucrose and reducing sugar content, kombucha layer biomass, and total acidity. Within
14-day fermentation process, the pH values showed decrease, the layers‘ mass presented considerable increase,
and the total acid content increased in the beverages. Overall, obtained data suggested that natural pomegranate
juice can be a potential candidate for further development as a functional beverage to support the maximum
human daily intake of glucuronic acid (45mg for a 70kg adult).
Keywords: acidity, fermentation, glucuronic acid, high-performance liquid chromatography, kombucha,
pomegranate juice, response surface methodology, sucrose, pH value
1. Introduction
Since 1914, many scientists have stated the healing effect of fermented tea fungus beverages on numerous
human diseases, such as inflammation of tonsils, colon colitis, and small intestine as well as risks of arteries
walls, blood pressure, structure sclerotic changes, and catarrhal angina (Jayabalan, Malbaša, Lončar, Vitas, &
Sathishkumar, 2014; Dufresne & Farnworth, 2000; Hartmann, Burleson, Holmes, & Geist, 2000; Barbancik,
1958). The health benefits of the beverages have been mostly established that are related to the significant
amounts of formed organic acid through fermentation process, such as glucuronic acid (Jayabalan et al., 2014;
Vına, Semjonovs, Linde, & Deninxa, 2014). Participation of acetic acid bacteria and yeasts through the
fermentation process qualify the kombucha layer in synthesizing cellulose along splitting sucrose into glucose,
fructose, and ethanol to produce glucuronic acid (Teoh, Heard, & Cox, 2004; Greenwalt, Steinkraus, & Ledford,
2000).
Besides the fermented kombucha beverages, a natural pomegranate juice has also been considered as a
functional beverage because of its enormous health effects especially on atherosclerosis and cardiovascular
diseases (Vına et al., 2014; Viuda-Martos, Fernández-López, & rez-Álvarez, 2010). It is well-known that its
nutritional value is due to having the substantial content of bioactive components such as phenol-carboxylic
http://jfr.ccsenet.org Journal of Food Research Vol. 7, No. 1; 2018
62
acids, anthoxanthins like flavonoids and anthocyanins, astringent-polyphenolic compounds such as tannins, and
antioxidants (Viuda-Martos et al., 2010). Moreover, due to high carbohydrates content and acidity, it can be
considered as a favourable substrate for fermentation process to produce organic acids, especially glucuronic
acid (Kazakos et al., 2016). Furthermore, Mousavi et al. (2013 & 2011) emphasized the fermentation suitability
of pomegranate juice, as a functional beverage.
Previous studies on pomegranate juice fermentation, as a single or mixed substrate, using kefir grains (Kazakos
et al., 2016), Saccharomyces cerevisiae yeast strains (Berenguer et al., 2016), and lactic acid bacteria
(Lactobacillus acidophilus and plantarum) (Mousavi et al., 2013; Filannino et al., 2013) have been reported.
However, so far, no analyses considered using kombucha symbiosis layer to ferment pomegranate juice to
evaluate the functional properties of produced fermented beverages (in terms of glucuronic acid content) has
been reported. As former studies on kombucha fermentation revealed, the basic biochemistry of beverage
components can be varied due to variability of sugar contents, incubation time periods, and influenced
temperatures. Thereby, in the present study, we aimed to investigate the potential of the glucuronic acid
production through pomegranate juice fermentation using kombucha culture, accompanied with measurements
of the changes in pH value, amount of final sucrose, reducing sugar, total acidity, and layer biomass within the
applied three treatment variables; cultivation sucrose content, temperature, and time, each in three levels. To not
only analyse the factors stimulate glucuronic acid production, but also determine the optimum relation between
the elements, statistical response surface methodology (RSM) method was applied. The massive total 27
multiple-factors experiments of the three elements, each with three levels, reduced to the 17
optimized-experiments in monitoring glucuronic acid production as well as other parameters.
Remarkably, the obtained results showed substantial effects of the three factors on glucuronic acid formation as
well as final chemical and physical properties of the produced beverages.
2. Materials and Methods
2.1 Pomegranate Juice
The pomegranate juice (PJ) products were supplied from the Takdaneh Agri & Ind. Co., Iran. Before shipping to
the laboratory, chemical and physical properties of the PJ products were examined by the company specialists, as
shown on Table 1. The three distinct concentrations of sucrose, as shown in Table 2, were dissolved in 1000ml of
the PJ products, as culture media, before pouring into the 5000ml-glass jars that had previously sterilized at
121°C for 20 min.
Table 1. Chemical and physical properties of pomegranate juice (PJ) products.
Nutrition value (per 1000 ml)
Total acid (g)
H
Glucuronic acid (g)
Carbohydrates (g)
Pomegranate juice (PJ)
10
3.5
0.4
Reducing sugars
Sucrose
5.5
6
2.2 Cultivation of Kombucha Layer
The kombucha layers were collected from the Persian Type Culture Collection, IROST. The previously bacterial
floral identification of the culture showed that the most abundant bacterial belong to the genera Acetobacter, such
as Acetobacter xylinum and A. aceti, as well as Gluconobacter. In addition, Saccharomyces, Koleckera, Pichia,
and Schizosaccharomyces were also recognized as the yeast species in the provided kombucha layers. Next, the
sucrose sweetened culture media were inoculated with 15% (w/v) kombucha biomass that had been aseptically
preserved in the PJ products at C temperature for 48hrs, before cultivation. Finally, the jars were properly
sealed with a sterilized mesh cloth (Figure 1) to maintain fermentation process under an aerobic atmosphere, free
of defects or debris, and inside the incubators at the three distinct temperatures, as shown in Table 2. Each jar
was sampled only at the three-time points, shown in Table 2, to avoid potential contamination.
Figure 1. An incubator with the sterilized-mesh sealed jars
http://jfr.ccsenet.org Journal of Food Research Vol. 7, No. 1; 2018
63
2.3 pH Value
The pH values were measured using an electronic pH meter (Metrohm model 827) calibrated at the pH 4 and 7,
at the room temperature. Three replicate measurements were performed.
2.4 Reducing Sugars and Remained Sucrose Content
The reducing sugars and remained sucrose, at the three sampling time points (Table 2), were determined using
the Lane-Eynon general volumetric method. Three replicate measurements were also performed.
2.5 Preparation of Glucuronic Acid Standard Solutions
Apparent concentration 20g/l of the HPLC-grade glucuronic acid, provided from the Fluka Chemical AG.
(Industriestrasse 25, CH-9741 Buchs Switzerland), as the primary stock standard solution was prepared by
dissolving proper amount of the solid powder in deionized water. Calibration standards for the glucuronic acid
analysis were prepared with blank deionized water, resulting in concentrations of 3, 5, 15g/l. The glucuronic acid
concentration for each individual sample was derived by comparison with the standard calibration curve (Figure
2).
Figure 2. Standard calibration curve of the HPLC-grade glucuronic acid
2.6 High-performance Liquid Chromatography (HPLC) Analysis of Glucuronic Acid Content
The HPLC samples preparation were performed according to the described method by Jayabalan et al. (2007)
with some modification. In brief: 20ml of the fermented beverages were centrifuged at 10,000rpm (RCF approx.
14,000×g) within 10min at C. Next, supernatant was diluted in 1/10 using a volumetric flask of 10ml filled
with 1/2ml of supernatant and redistilled water. The obtained extract directly passed through the HPLC millipore
filter (0.45 µ) vials. A 20µl filtrate was injected to a reverse-phase-chromatography system equipped with a
Nucleocil C-18 column (4mm ID ×250mm, m), a single pump Bischoff, and a UV detector. The 50mM
sodium dihydrogen phosphate at pH~2.58 was used as a mobile phase. The flow rate 1.0ml/min was maintained
at ambient temperature. Detection was carried out at 210nm. Obtained peaks were chronicled on the standard
HPLC curve (Figure 2) and multiplied by the dilution factors to quantify the acid concentrations. A typical
chromatogram of the assay for glucuronic acid at the substrate concentration of 0.53g/l was shown in Figure 3.
Figure 3. HPLC chromatogram of the glucuronic acid identification in the fermented SPJ with concentration
0.53g/l acid. *; Position of the glucuronic acid peak
2E+6
4E+6
6E+6
8E+6
10E+6
05 10 15 20 25
Concentration of Glucuronic acid (g/l)
Absorbance
y=429,927.66x+305,614.96
R =1.00
2
http://jfr.ccsenet.org Journal of Food Research Vol. 7, No. 1; 2018
64
2.7 Yield of Biomass
The kombucha biomass was determined using a mass measurement method, described by Malbasa, Loncar, &
Djuric, (2008). Briefly, the grown floating cellulosic layer was removed from surface of the fermented beverages
(Figure 4), rinsed with distilled water, and dried with filter paper before measuring the weight, at the three time
points (Table 2). Three replicate measurements were performed.
Figure 4. The harvested mother and daugther floating cellulosic layers
2.8 Experimental Design
To locate the optimum vicinity of the three-element and three-level effective media factors involved in a
glucuronic acid production, including: sucrose content, temperature degree, and time period, the statistical RSM
method using the Design Expert Version 6.0.10 (Stat-Ease, USA) was applied, as described by Sayyad, Panda,
Javed, & Ali, (2007). The statistical design of the experiments along with nature of the response surface
estimation, in the optimum region, resulted in a total number of 17 experiments, given in Table 2.
Table 2. Independent variables and their coded and actual values in the experimental design.
Independent variable
Units
Symbol
Coded level
-1
0
1
Temperature
°C
X1
18
27
37
Time
day
X2
4
9
14
Sucrose
g/l
X3
6
8
10
3. Results and Discussion
3.1 pH Value
During the fermentation process, the initial pH value of the PJ products ~3.5 (Table 1) dropped to the lowest
value ~2.58, within 14 days, and the highest value ~2.88, on day 4 of the fermentation process (Table 3). This
observation could be associated mainly to a remarkable amount of organic acids, especially acetic acids
produced through sucrose metabolism and ethanol oxidization via mutual act of kombucha bacteria and yeasts
mutual act, within fermentation process (Jayabalan et al., 2016; Jayabalan et al., 2014; Chen & Liu, 2000). This
pH reduction was well correlated to the observed increase in the total acidity of the fermented beverages formed
within 14-day process of fermentation (Table 3). It also was consistent with the reports from Jayabalan et al.
(2016 & 2007). Worth to note that the observed values for pH were slightly lower in compare to the previously
published reports of kombucha fermented beverages benefited other different substrates, such as sweetened black
tea (Jayabalan, Marimuthu, & Swaminathan, 2007), sweetened sour cherry juice (Yavari, Assadi, Moghadam, &
Larijani, 2011), sweetened grape juice (Yavari, Assadi, Moghadam, & Larijani, 2010), and even cheese whey
(Belloso-Morales, & Hernández-Sánchez, 2003). However, it was in line with the previous studies presented on
apple tea wine by Kumar & Joshi (2016), and on red grape juice by Ayed et al., (2017). The surface plot of the pH
value (as a function of the two independent variables; fermentation time (X2) and temperature (X1)), at the
sucrose content (X3) 8g/l, were shown on Figure 5-a.
3.2 Total Acidity
The total acid content of the fermented beverages was changed from the initial amount 10g/l in PJ products
(Table 1) to the range value 4.2-26.6g/l at the end of the fermentation process (Table 3). As recently determined,
various type of acids, predominantly acetic, gluconic, glucuronic, citric, L-lactic, malic, tartaric, malonic, oxalic,
succinic, pyruvic, and usnic acids can be produced in kombucha beverages during fermentation process
(Jayabalan et al., 2016). Thus, while we only investigated the changes in glucuronic acid content during
http://jfr.ccsenet.org Journal of Food Research Vol. 7, No. 1; 2018
65
fermentation process, the continuously increase in total acidity of the beverages implied the endless production
of tremendous amount of acids within 14-day fermentation process (Table 3). The surface plot analysis of total
acidity content in beverages presented in Figure 1-b, as a function of the two independent variables; fermentation
time (X2) and temperature (X1), at sucrose content (X3) 8g/l.
It is worth noting that the total acidity content of the fermented beverages varied according to the time period of
the process (Table 3), which is in accordance with the previous findings (Yavari et al., 2011; Yavari et al., 2010;
Jayabalan et al., 2007). However, kumar et al. (2016) indicated that the fermentation period beyond 10 days may
cause the high acidity level with harmful potentiality to human body in direct intake. Therefore, further studies
might be aimed to carry out the fermentation process to reduce the acidity of fermented beverages, while
sustaining the high-level production of glucuronic acid and other bioactive metabolites.
3.3 Glucuronic Acid Content
Glucuronic acid content of the unfermented and unsweetened PJ products ~4.32g/l (Table 1), showed an
extensive variation, at the range of ~0.42-17.07g/l, in the final sweetened and fermented beverages during
14-day fermentation process (Table 3). Previous studies showed that the maximum amount of glucuronic acid
~2.3g/l produced in 12-day fermented beverages, using black tea as a substrate (Jayabalan et al., 2007), while
our study presented the maximum amount of glucuronic acid ~17.07g/l for 14-day fermented beverages (Table 3).
Considerable variations in glucuronic acid production observed when the PJ products were subjected to the
various combination of temperature and time within various sucrose content (Table 3). Thereby, in our study, the
significant increase in glucuronic acid content of the beverages suggested the incredible capability of the
sweetened pomegranate, as a substrate, and the optimized fermentation conditions, shown in Table 2, in yielding
the high amount of glucuronic acid. Remarkably, the yeasts of the kombucha culture are able to hydrolyze the
media sucrose into glucose, which is transferred and consequently oxidized at sixth carbon by acetic acid
bacteria of the layer to produce glucuronic acid (Jayabalan et al., 2016; & Jayabalan et al., 2007). Hence, the
continuously increase in glucuronic acid content observed during fermentation process could obviously supposed
the proper relationship between the acid bacteria, A. xylinum and A. aceti, and the Saccharomyces, Koleckera,
Pichia, and Schizosaccharomyces yeasts of the kombucha layer in sweetened pomegranate substrate under the
fermentation process condition (Table 2). Furthermore, our observation was someway consistent with the study
from Nguyen et al. (2015) that indicated the highly effectiveness of removing unwanted microbial strains of the
kombucha culture in producing glucuronic acid to over 17.5mg/l, in compared to the traditional kombucha.
Table 3. BoxBehnken design (BBD) matrix for three factors (Temp, Time, and Sucrose) along with the obtained
data of six responses (glucuronic acid, remained sucrose, reducing sugar, total acidity, biomass, and pH) for PJ
products fermentation process. The PJ products were fermented and sampled as described in ‗‗Materials and
Methods‘‘. The data were expressed as means ±SD of three replicates
Temp
Time
Sucrose
Glucuronic
acid
Remained
sucrose
Reducing
sugar
Total
acidity
Biomass
pH
°C
day
g/l
g/l
g/l
g/l
g/l
g
_
18
4
8
0.53+0.01
6.11+0.01
2.2+0.04
4.7+0.05
53.72+0.02
2.88+0.01
18
9
10
1.21+0.04
5.04+0.02
0.69+0.01
9.4+0.01
112.0+0.05
2.8+0.01
18
9
6
0.42+0.04
5.64+0.01
0.76+0.01
9.4+0.02
81.38+0.04
2.83+0.01
18
14
8
6.2+0.04
5.68+0.01
0.9+0.05
15.2+0.02
106.7+0.05
2.76+0.01
27
4
6
0.43+0.03
2.04+0.01
1.8+0.02
4.2+0.03
128.8+0.01
2.87+0.02
27
4
10
0.73+0.01
9.01+0.01
1.5+0.03
7.1+0.01
122.3+0.02
2.84+0.02
27
9
8
2.45+0.01
7.51+0.02
0.67+0.01
15.6+0.02
104.0+0.01
2.8+0.02
27
9
8
2.37+0.02
5.92+0.04
0.48+0.04
8.7+0.03
130.8+0.01
2.82+0.01
27
9
8
3.22+0.01
5.63+0.03
0.55+0.01
13.1+0.02
111.6+0.02
2.8+0.02
27
9
8
2.5+0.03
4.14+0.02
0.64+0.05
10.3+0.02
128.6+0.01
2.82+0.01
27
9
8
2.95+0.01
7.85+0.02
0.55+0.02
13.2+0.01
115.4+0.01
2.81+0.01
27
14
6
3.53+0.02
4.11+0.03
0.98+0.01
12.4+0.01
286.4+0.04
2.65+0.02
27
14
10
6.4+0.04
5.01+0.01
0.51+0.02
14.8+0.01
294.3+0.01
2.69+0.02
37
4
8
5.62+0.03
3.17+0.03
1.31+0.02
8.9+0.04
28.73+0.01
2.79+0.01
37
9
10
5.78+0.04
4.85+0.01
1.1+0.05
14.4+0.05
213.8+0.05
2.71+0.01
37
9
6
5.67+0.05
4.01+0.02
1.14+0.06
11.4+0.03
179.5+0.02
2.72+0.01
37
14
8
17.07+0.0
1.45+0.03
0.38+0.02
26.6+0.04
280.6+0.05
2.58+0.01
http://jfr.ccsenet.org Journal of Food Research Vol. 7, No. 1; 2018
66
3.4 Reducing Sugar and Remained Sucrose
The PJ products were sweetened with three different concentrations of sucrose, as shown in Table 2. Initial
content of reducing sugars 5.5g/l and remained sucrose 6g/l for the PJ products (Table 1) showed changes to
~0.38-2.2g/l and 1.45-9.01g/l range value, respectively. These changes accompanied with increase in the total
acidity of the final fermented beverages ~4.2-26.6g/l within 14 days of the fermentation process, as shown in
Table 3. During kombucha fermentation, enzymes of the yeasts, such as invertase and sucrase, assist culture to
hydrolyze the media sugar, sucrose, into mixture of the reducing sugars glucose, and fructose, which are
prerequisite component for ethanol, and consequently organic acids production throughout the kombucha aerobic
fermentation process (Jayabalan et al., 2014; Chen & Liu, 2000). Thereby, the high content of the total acidity
and glucuronic acid recommended highly action of the kombucha culture microbes on media sugar. Moreover,
elevated amount of glucuronic acid along with contrary changes in amount of the remained sucrose and reducing
sugars, decreased and increased respectively, indicated that the added sucrose to the media was continuously
hydrolysed to the reducing sugars to produce organic acids. This observation was consistent with the recent
results from Jayabalan et al. (2016). Furthermore, small varied range of the remained sucrose among the
beverages (Table 3 & Figure 5-d), indicated that the sucrose consumption rates through fermentation process
were almost the same. However, the lowest amount of remained sucrose ~1.45g/l for the media with the highest
amount of produced glucuronic acid might suggested that the involved yeasts and bacteria, in the kombucha
fermentation process, were probably more active and durable during 14 days of fermentation.
a) b)
c) d)
e)
Figure 5. Surface plots of the pH value (a); acidity (b); glucuronic acid (c); remained sucrose (d) and reducing
sugar (e) changes of the PJ products fermented as a function of temperature (A: Temp) and fermentation time (B:
Day). The PJ products were fermented and sampled as described in ‗‗Materials and Methods‘‘
3.5 Yield of Biomass
The smallest layer mass ~28.73g, and the largest mass ~294.3g were obtained on 4 and 14 days after
fermentation process, respectively (Table 3). Therefore, it was obvious that the fermentation period had a
tremendous effect on the kombucha biomass yield. Furthermore, not only time period of the process, but also
pH
A: Temp
180
135
90
45
0
14.00 11.50 9.00 6.50 4.00
37.00
32.25
27.50
22.75
18.00
B: Day
Acidity
B: Day A: Temp
230
185
140
95
50
14.00 11.50 9.00 6.50 4.00
37.00
32.25
27.50
22.75
18.00
Glucuronic acid
180
135
90
45
0
14.00 11.50 9.00 6.50 4.00
37.00
32.25
27.50
22.75
18.00
B: Day A: Temp
37
27.5
18
8.5
0
14.00 11.50 9.00 6.50 4.00
37.00
32.25
27.50
22.75
18.00
Remained sucrose
B: Day A: Temp
2.700
2.275
1.85
1.425
1
14.00
11.50
9.00
6.50
4.00
37.00 32.25 27.50 22.75 18.00
Reducing sugar
B: Day A: Temp
http://jfr.ccsenet.org Journal of Food Research Vol. 7, No. 1; 2018
67
reducing sugar content such as glucose, produced from the decomposed sucrose, showed profound influence on
cellulose and hemi-cellulose production (BauerPetrovska & PetrushevskaTozi, 2000). While later revealed
by keshk & Sameshima, (2006) that reducing sugar, as a carbon source, can have a relative contradictory
function in acid and biomass production, our observation was not consistent with their arguments.
3.6 Sensory Characteristics
When the symbiosis culture placed in the jars containing the PJ products, the CO2, generated through the
fermentation process by the yeasts, accumulated in the interface between the the PJ products media and the
kombucha layer to create an anaerobic atmosphere to allow the fermentation process to fulfilled (Malbasa et al.,
2008; Jayabalan et al., 2007). During fermentation process, the PJ products turned into the light red colored with
a sour taste, little sparkling surface, and acidified smell beverages. Evaluation tests exhibited that the acidity
tastes of the beverages, even on 14 days after fermentation process, were acceptable from the sensory
characteristics viewpoint (Table 4). The endpoint sensory analysis of the fermentation process, on day 14,
showed the considerable increase in both sugar and alcohol contents, while the acidic taste moves from sweet to
remarkable sour (Table 4).
Table 4. Sensory evaluation of the fermented PJ products. The fermented beverages were fermented and sampled
as described in ‗‗Materials and Methods‘‘. Data extracted from a team of 16 evaluators in three replicates.
Temp
Time
Sucrose
CO2
content
Sugar
taste
Acidic
taste
Alcoholic
taste
Ferment
smell
Transparency
18
4
8
3
2
3
2
2
5
18
9
10
2
2
3
2
1
4
18
9
6
3
1
2
1
2
4
18
14
8
3
3
3
1
1
5
27
4
6
4
1
3
2
3
3
27
4
10
3
1
4
2
5
2
27
9
8
4
3
1
1
2
3
27
9
8
2
2
2
5
4
4
27
9
8
3
1
1
1
3
3
27
9
8
2
2
1
1
4
4
27
9
8
2
2
2
4
2
4
27
14
6
4
2
3
2
3
4
27
14
10
3
2
2
2
4
3
37
4
8
4
3
2
5
3
1
37
9
10
3
2
1
5
4
1
37
9
6
1
2
1
5
3
1
37
14
8
4
3
3
5
3
1
Note: The sensory evaluation criteria; Scores 1-5 were describing dislike extremely, disliked moderately, neither
liked nor disliked, liked moderately, and liked extremely, respectively.
4. Conclusion
In the current study, the entire obtained data suggested that among the various traditional substrates used to
produce the glucuronic acid, pomegranate juice presented as the desired substrate to produce the considerable
amount of glucuronic acid with the highest value of 17.07g/l. Also, high production of the glucuronic acid along
biomass yield suggested the usefulness of the pomegranate juice, as a cost-effective substrate source, in
high-yield industrial production that indicated as a key issue by Hong & Qiu, (2008).
References
Ayed, L., Ben Abid, S., & Hamdi, M. (2017). Development of a beverage from red grape juice fermented with
the Kombucha consortium. Annals of Microbiology, 67(1), 111-121.
https://doi.org/10.1007/s13213-016-1242-2
Barbancik, G. F. (1958). Cainii grib I ego Lacèbnye svoistva. Izdame Tretye. Omsk: Omskoe oblastnoe kniznoe
izdatelstvo. 54 pages (Il fungo del -Cainii grib è il nome del Kombucha in russo - e le sue proprietà
terapeutiche terza edizione)
BauerPetrovska, B., & Petrushevska, Tozi, L. (2000). Mineral and water soluble vitamin content in the
http://jfr.ccsenet.org Journal of Food Research Vol. 7, No. 1; 2018
68
Kombucha drink. International journal of food science & technology, 35(2), 201-205.
https://doi.org/10.1046/j.1365-2621.2000.00342.x
Belloso-Morales, G., & Hernández-Sánchez, H. (2003). Manufacture of a beverage from cheese whey using a
"tea fungus" fermentation. Revista Latino Americana de Microbiologea, 45, 5-11
Berenguer, M., Vegara, S., Barrajón, E., Saura, D., Valero, M., & Martí, N. (2016). Physicochemical
characterization of pomegranate wines fermented with three different Saccharomyces cerevisiae yeast
strains. Food Chemistry, 190, 848-855. https://doi.org/10.1016/j.foodchem.2015.06.027
Chen, C., & Liu, B. Y. (2000). Changes in major components of tea fungus metabolites during prolonged
fermentation. Journal of Applied Microbiology, 89(5), 834-839.
https://doi.org/10.1046/j.1365-2672.2000.01188.x
Dufresne, C., & Farnworth, E. (2000). Tea, kombucha, and health: a review. Food Research International, 33,
409-421. https://doi.org/10.1016/S0963-9969(00)00067-3
Filannino, P., Azzi, L., Cavoski, I., Vincentini, O., Rizzello, C. G., Gobbetti, M., & Cagno, R. D. (2013).
Exploitation of the health-promoting and sensory properties of organic pomegranate (Punica granatum L.)
juice through lactic acid fermentation. International Journal of Food Microbiology, 163(2), 184-192.
https://doi.org/10.1016/j.ijfoodmicro.2013.03.002
Greenwalt, C. J., Steinkraus, K. H., & Ledford, R. A. (2000). Kombucha, the fermented tea: microbiology,
composition, and claimed health effects. Journal of Food Protection, 63(7), 976-981.
https://doi.org/10.4315/0362-028X-63.7.976
Hartmann, A. M., Burleson, L. E., Holmes, A. K., & Geist, C. R. (2000). Effects of chronic kombucha ingestion
on open-field behaviors, longevity, appetitive behaviors, and organs in C57-BL/6 mice: a pilot study.
Nutrition, 16, 755-761. http://dx.doi.org/10.1016/S0899-9007(00)00380-4
Hong, F., & Qiu, K. Y. (2008). An alternative carbon source from konjac powder for enhancing production of
bacterial cel- lulose in static cultures by a model strain Acetobacter aceti subsp xylinus ATCC 23770.
Carbohyd Polym, 72(3), 545-549. https://doi.org/10.1016/j.carbpol.2007.09.015
Jayabalan, R., Malbaša, R. V., & Sathishkumar, M. (2016). Kombucha Tea: Metabolites. Fungal Metabolites:
1-14.
Jayabalan, R., Malbaša, R. V., Lončar, E. S., Vitas, J. S., & Sathishkumar, M. (2014). A Review on Kombucha
TeaMicrobiology, Composition, Fermentation, Beneficial Effects, Toxicity, and Tea Fungus.
Comprehensive Reviews in Food Science and Food Safety, 13(4), 538-550.
https://doi.org/10.1111/1541-4337.12073
Jayabalan, R., Marimuthu, S., Swaminathan, K. (2007). Changes in content of organic acids and tea polyphenols
during kombucha tea fermentation. Food Chemistry, 102, 392-398.
https://doi.org/10.1016/j.foodchem.2006.05.032
Kazakos, S., Mantzourani, I., Nouska, C., Alexopolos, A., Bezirtzoglou, E., Bekatorou, A., Plessas, S., &
Varzakas, T. (2016). Production of Low-Alcohol Fruit Beverages Through Fermentation of Pomegranate
and Orange Juices with Kefir Grains. Current Research in Nutrition and Food Science, 4(1), 19-26.
http://dx.doi.org/10.12944/CRNFSJ.4.1.04
Keshk, S., & Sameshima, K. (2006). The utilization of sugar cane molasses with/without the presence of
lignosulfonate for the production of bacterial cellulose. Applied microbiology and biotechnology, 72(2),
291-296. https://doi.org/10.1007/s00253-005-0265-6
Kumar, V., & Joshi, V. K. (2016). Kombucha: Technology, Microbiology, Production, Composition and
Therapeutic Value. International Journal of Food and Fermentation Technology, 6(1), 13-24.
https://doi.org/10.5958/2277-9396.2016.00022.2
Malbasa, R. V., Loncar, E. S., & Djuric, E. (2008). Comparison of the products of kombucha fermentation on
sucrose and molasses. Food Chemistry, 106(3), 1039-1045. https://doi.org/10.1016/j.foodchem.2007.07.020
Mousavi, Z. E., Mousavi, S. M., Razavi, S. H., Hadinejad, M., Emam-Djomeh, Z. & Mirzapour, M. (2013).
Effect of Fermentation of Pomegranate Juice by Lactobacillus plantarum and Lactobacillus acidophilus on
the Antioxidant Activity and Metabolism of Sugars, Organic Acids and Phenolic Compounds. Food
Biotechnology, 27(1), 1-3. http://dx.doi.org/10.1080/08905436.2012.724037
Nguyen, N. K., Nguyen, P. B., Nguyen, H. T., & Le, P. H. (2015). Screening the optimal ratio of symbiosis
http://jfr.ccsenet.org Journal of Food Research Vol. 7, No. 1; 2018
69
between isolated yeast and acetic acid bacteria strain from traditional kombucha for high-level production
of glucuronic acid. LWT-Food Science and Technology, 64(2), 1149-1155.
https://doi.org/10.1016/j.lwt.2015.07.018
Sayyad, S. A., Panda, B. P., Javed, S., & Ali, M. (2007). Optimization of nutrient parameters for lovastatin
production by Monascus purpureus MTCC 369 under submerged fermentation using response surface
methodology. Applied Microbiology and Biotechnology, 73(5), 1054-1058.
https://doi.org/10.1007/s00253-006-0577-1
Teoh, A. L., Heard, G., & Cox, J. (2004). Yeast ecology of Kombucha fermentation. International Journal of
Food Microbiology, 96(2), 119-126. https://doi.org/10.1016/j.ijfoodmicro.2003.12.020
Vına, I., Semjonovs, P., Linde, R., & Deninxa, I. (2014). Current Evidence on Physiological Activity and
Expected Health Effects of Kombucha Fermented Beverage. Journal of Medicinal Food, 17(2), 179-188.
https://doi.org/10.1089/jmf.2013.0031
Viuda-Martos, M., Fernández-López, J., & rez-Álvarez, J. A. (2010). Pomegranate and its Many Functional
Components as Related to Human Health. Comprehensive Reviews in Food Science and Food Safety, 9(6),
635-654. https://doi.org/10.1111/j.1541-4337.2010.00131.x
Yavari, N., Mazaheri, A. M., Larijani, K., & Moghadam, M. B. (2010). Response surface methodology for
optimization of glucuronic acid production using kombucha layer on sour cherry juice. Australian Journal
of Basic Applied Science, 4(8), 3250-3256
Yavari, N., Assadi, M. M., Moghadam, M. B., & Larijani, K. (2011). Optimizing glucuronic acid production
using tea fungus on grape juice by response surface methodology. Australian Journal of Basic Applied
Science, 5, 1788-1794
Copyrights
Copyright for this article is retained by the author(s), with first publication rights granted to the journal.
This is an open-access article distributed under the terms and conditions of the Creative Commons Attribution
license (http://creativecommons.org/licenses/by/4.0/).
... Microbiol. 2022, 2 77 beneficial in terms of their functional compounds, but they can also stimulate the increased formation of organic acids such as glucuronic acid under favourable fermentation conditions [50][51][52]. ...
... Fruits and vegetables have also emerged as potential kombucha substrates, with researchers again focusing on those wellcharacterised in terms of their bioactive compounds and potential health benefits. Such studies have investigated the use of raw materials such as spinach, grape juice, cherry juice, banana peel and pomegranate juice [45,[47][48][49][50][51][52]. Not only are these substrates beneficial in terms of their functional compounds, but they can also stimulate the increased formation of organic acids such as glucuronic acid under favourable fermentation conditions [50][51][52]. ...
... Such studies have investigated the use of raw materials such as spinach, grape juice, cherry juice, banana peel and pomegranate juice [45,[47][48][49][50][51][52]. Not only are these substrates beneficial in terms of their functional compounds, but they can also stimulate the increased formation of organic acids such as glucuronic acid under favourable fermentation conditions [50][51][52]. ...
Article
Full-text available
Kombucha is a carbonated, slightly acidic beverage traditionally produced by the fermentation of sweetened tea by a symbiotic culture of bacteria and yeast (SCOBY). The microbial community of kombucha is a complex one, whose dynamics are still not fully understood; however, the emergence of culture-independent techniques has allowed a more comprehensive insight into kombucha microbiota. In recent times, advancements have been made towards the optimisation of the fermentation process, including the use of alternative substrates, defined starter cultures and the modification of fermentation parameters, with the aim of producing an innovative beverage that is improved in terms of its physiochemical, sensory and bioactive properties. The global kombucha market is rapidly increasing, with the rising popularity of the tea attributed in part to its purported health benefits, despite the lack of research in human subjects to substantiate such claims. Accordingly, the incidence of kombucha home-brewing has increased, meaning there is a requirement for individuals to recognise the potential hazards associated with fermentation and the relevant preventative measures to be undertaken to ensure the safe preparation of kombucha. The aim of this review is to provide an update regarding the current knowledge of kombucha production, microbiology, safety and marketing.
... Sour cherry, grape, and pomegranate juices which are a source of biologically active ingredients were also used to produce functional beverages with a high glucuronic acid content [109][110][111]. Glucuronic acid is one of the most valuable healthy Kombucha components, which has a detoxifying effect [112]. ...
... Glucuronic acid is also a precursor of vitamin C [113], and it takes part in the prevention of chronic degenerative cardiovascular and neurodegenerative diseases and cancer [92,100]. e maximum yield of glucuronic acid was obtained on sour cherry and pomegranate juices supplemented with 0.8% of sucrose [109][110][111] and on grape juice supplemented with 0.7% of sucrose [110]. e yield of glucuronic acid obtained on the different juices was higher than that obtained in the black tea. is increase was explained by the high carbohydrates' content in these juices. ...
Article
Full-text available
In recent years, the request for the functional beverages that promote health and wellness has increased. In fact, fermented juices are an excellent delivering means for bioactive components. Their production is of crucial importance to supply probiotics, in particular, for people with particulars needs like dairy-product allergic consumers and vegetarians. This review focuses on recent findings regarding the microbial composition and the health benefits of fermented fruit and vegetable beverages by lactic acid bacteria, kefir grains, and SCOBY as well as discussing the metabolites resulting from these fermentations process. Moreover, limits that could restrain their production at the industrial level and solutions that have been proposed to overcome these constraints are also reviewed.
... Some authors evaluated kombucha fermentation using carbon sources, such as sour cherry juice, grape juice, pomegranate juice, soy milk, and even Jerusalem artichoke extract (Helianthus tuberosus). Promising results were found regarding obtaining metabolites of interest, such as glucuronic acid, increased antioxidant potential, or even low-calorie beverages [47][48][49][50][51]. In quantitative terms, Lonc ar and colleagues [52] showed that the kinetics of sucrose consumption is complex. ...
Article
Full-text available
Fermentation is one of the oldest biotechnological tools employed by mankind. Fermenting food gives them better sensory and nutritional qualities, the latter including vitamins, phenolic compounds, antioxidants, and antimicrobials. Kombucha is the result of the fermentation of a sweetened Camellia sinensis infusion by the action of a symbiotic community of yeasts and bacteria organized in a cellulosic biofilm called SCOBY and has gained great prominence among fermented foods and beverages, with a considerable increase in its popularity in the last decade, both among consumers and within the scientific community. This is explained by the particular functional and microbial characteristics of this beverage, such as its antioxidant and antimicrobial potential, long-term stable microbial communities, its suitability for fermentation under different conditions of time and temperature, and amenability to other carbon sources besides sucrose. Thus, this review aims to present and discuss the functional, microbial, and physicochemical aspects of kombucha fermentation, covering the many challenges that arise in its production, in domestic, commercial, and legislation contexts, and the next steps that need to be taken in order to understand this drink and its complex fermentation process.
... There fore, honey used as an al ter na tive source to the usual car bon source for the fer men ta tion of kom bucha, i.e. su crose, in the pre sent study, and the re sults in di cated that the use of honey was rec ommended to strengthen the an tiox i dant ac tiv ity of su crose. Sour cherry juice is very pop u lar drink not only be cause of its growth and consump tion in al most all coun tries of the world, but also be cause of neochloro genic acid, 3 -coumaroyl -ouinic acid, chloro genic acid, and epi cat e chin that cre ate a very high an tiox i dant po ten tial and re move free rad i cals ( Yavari et al., 2010 ). Cof fee was used in the test due to the high an tiox i dant po ten tial of kom bucha en riched sam ples with cof fee and the pres ence of chloro genic acid, ans its de riv a tives as well as caf feic acid as the most im por tant polyphe no lic com pounds in coffee with a very large ca pac ity to re move free rad i cals. ...
Article
The beneficial effects of antioxidant production activity during kombucha tea fermentation elevate the nutritional values of this product. The present study aimed to enhance antioxidant properties and invertase activity in kombucha tea and investigate the synergistic effects of both properties. Following preparation of kombucha solution, the Plackett–Burman design was used for determination of factors affecting the antioxidant and invertase activities in the product. Samples were collected from the fermenting solution on days 0, 7, 10 and 14. The total phenol content of samples was determined using the Folin–Ciocalteau method. In addition, antioxidant activity was measured using cupric ion reducing antioxidant capacity and DPPH (1,1-diphenyl 2-picrylhydrazyl) radical inhibition method. Invertase activity was determined in the samples using sigma protocol. After screening design, the dried starter containing the kombucha tea microbial consortium optimally produced using the vacuum freeze drying method. The results showed that pH of kombucha reduced as the fermentation time passed. Antioxidant activity increased in most samples over time, so that the average antioxidant activity was in the range of 0.99–224.86 nm of trolox equivalents/ml during fermentation. Invertase activity also increased in the most samples during fermentation and showed the range of 50.85–115.5 u/ml. By increasing the activity of invertase, the antioxidant activity of kombucha solution increased. The results of present study proposed that by induction of invertase activity in kombucha drink its effectiveness that resulted by antioxidant properties would be promoted and the drink will be more useful for diabetic patients.
... Usually, black (Theae nigre folium) or green tea (Theae viridis folium) is used as a principal base beverage, but there have been preparations made with oolong, lemon balm, jasmine, mulberry, and peppermint tea [5]. Other preparations include pomegranate, grape, and sour cherry juice [6][7][8]. Some investigations have also involved the use of coconut water [9] and coffee [10]. ...
Article
Full-text available
Purpose of the review: Glucuronic acid is contained naturally in kombucha beverages due to the associations between bacteria and yeasts during its fermentation. The purpose of this review is to describe the literature related to the hepatoprotective effect associated with glucuronic acid present in different kombucha beverages. Recent findings: Although previous research supports beneficial hepatoprotective effects of glucuronic acid consumption from kombucha, these effects are mainly attributed to the tea phytochemicals. However, there are some improvements in methodological deficiencies in some in vivo studies that should be considered. There is no sufficient evidence to generalize the adverse effects of kombucha consumption. Consumption of kombucha could be considered a safe practice in healthy populations due to its hepatoprotective effects. The content of the beneficial or toxic components is very variable because it depends on its manufacturing process. In persons with side sickness, other conditions such as pregnancy, and hypersensitivity to some kombucha components, a restriction in its consumption must be advisable.
Article
Full-text available
Kombucha has been gaining prominence around the world and becoming popular due to its good health benefits. This beverage is historically obtained by the tea fermentation of Camellia sinensis and by a biofilm of cellulose containing the symbiotic culture of bacteria and yeast (SCOBY). The other substrates added to the C. sinensis tea have also been reported to help kombucha production. The type as well as the amount of sugar substrate, which is the origin of SCOBY, in addition to time and temperature of fermentation influence the content of organic acids, vitamins, total phenolics, and alcoholic content of kombucha. The route involved in the metabolite biotransformation identified in kombucha so far and the microorganisms involved in the process need to be further studied. Some nutritional properties and benefits related to the beverage have already been reported. Antioxidant and antimicrobial activities and antidiabetic and anticarcinogenic effects are some of the beneficial effects attributed to kombucha. Nevertheless, scientific literature needs clinical studies to evaluate these benefits in human beings. The toxic effects associated with the consumption of kombucha are still unclear, but due to the possibility of adverse reactions occurring, its consumption is contraindicated in infants and pregnant women, children under 4-years-old, patients with kidney failure, and patients with HIV. The regulations in place for kombucha address a number of criteria, mainly for the pH and alcohol content, in order to guarantee the quality and safety of the beverage as well as to ensure transparency of information for consumers.
Article
Full-text available
Abstract In this study, physicochemical, microbiological, and sensory properties, antibacterial and antifungal effects of kombucha teas produced with some small berry fruits (blackberry, raspberry, and red goji berry) were investigated. During fermentation, titratable acidity and pellicle biomass weights increased whereas water activity, brix, viscosity, L* and b* values decreased. At the end of fermentation, the highest minerals determined in the samples were potassium and magnesium. Also, catechin and gallic acid were detected in all samples. Samples produced with blackberry were the most appreciated ones in all criteria. The highest antibacterial and antifungal effects were determined in samples containing blackberries on Staphylococcus aureus and Rhizopus nigricans (24.36 and 20.53 mm zone diameters). The antibacterial effect, MIC, and MBC values (0.023 and 0.016 mg/L) on Staphylococcus aureus. Regarding the antifungal effect, the MIC and MFC values were determined in tea produced with blackberry on Rhizopus nigricans with 0.035 mg/L, and 0.023 mg/L.
Article
The large-scale availability of glucuronic acid for industrial sectors is limited due to involving costly conventional purification strategies. Here, aqueous two-phase system (ATPS) was used as potent economical platform for selective recovery of D-glucuronic acid. Paenibacillus apiarus MTCC 2192 produced extracellular D-glucuronic acid with maximum yield (0.657 mg/ml) during late log phase. D-glucuronic acid was extracted after treating cell free extract with ATPS system consisting 10% PEG and 15% Potassium hydrogen phosphate (PHP) salt. It showed maximum recovery (82.97%) with lower concentration (5%) of high molecular weight of PEG 6000. The increased concentration of PHP-salt from 10 to 25% (w/w) and variation of pH (4–9) favours high recovery of D-glucuronic acid in top phase due to removal of majority of inhibitory protein component. ATPS with 5% PEG 6000 and 25% PHP-salt showed higher recovery of D-glucuronic acid (84.20%) at pH-4 and could be used as low-cost bio-separation tool to fulfil its great demand.
Article
Kombucha is a functional tea brewed through a symbiotic culture of bacteria and yeast (SCOBY). It is applicable to various industrial sectors due to its several noteworthy features. Therefore, this study aims to elucidate the following technological aspects of kombucha/SCOBY: (a) the effect of its production parameters on different scales, (b) microbiota features and factors that affect biofilm formation and fermentation so as to demonstrate its potential applications in different industrial sectors, and (d) how its consumption affects human health according to evidence collected in literature. Its production seldom occurs on an industrial scale and studies assessing its large-scale fermentation process are scarce. Various industrial sectors have benefited from SCOBY, such as the food industry, biotechnological processes and biomedicine. However, industrial applications require optimization of some parameters, such as specific equipment for product standardization aimed at cost reduction and process profitability.
Article
Soymilk fermentation with kombucha was perfomed at 28 °C and 37 °C, and changes in the number of microorganisms, bioactivity and chemical compositions were analyzed during fermentation. Yeast, acetic acid bacteria (AAB), and lactic acid bacteria (LAB) showed substantial growth in the soymilk, and fermentation at 37 °C and 28 °C promoted the growth of LAB and AAB, respectively. The flatulence factors of raffinose and stachyose were entirely and mostly consumed during fermentation, respectively. Nearly all the glucoside isoflavones were transformed into aglycone isoflavones by β-glucosidase hydrolysis. Total phenolic, ferulic, chlorogenic and ascorbic acid (VC) contents significantly increased after fermentation. The antioxidant and inhibition activities to α-glucosidase and α-amylase of kombucha-fermented soymilk significantly increased, and were higher at 37 °C than at 28 °C. In conclusion, fermentation with kombucha can enhance the health-promoting properties of soymilk.
Article
Full-text available
Kombucha, Tea Kvass, Japanese or Indonesian tea fungus and Manchurian are the most common names for the symbiotic association of bacteria and osmophilic yeast in a form of thick jelly membrane which is cultured in sugared tea. It is slightly sweet, acetic acid-fl avoured beverage also called tea eider the traditional substrate for kombucha preparation is black tea sweetened with 5 to 15% of sucrose and produced during 6 to 10 days of fermentation under aerobic conditions, at a temperature range of 20 to 30°C. The fermentation is two steps fermentation in which, the yeasts ferment the sugar to ethanol, which is further oxidised by the acetic acid bacteria to produce acetic acid which reduces the pH of medium. Except black tea, diff erent types of other tea’s such as orthodox tea and herbal tea have been used for the production of apple tea wine, using natural and inoculated fermentation. Besides acetic acid, the fermented liquid contains gluconic, glucuronic and lactic acid, among them all glucuronic acid is the main therapeutic agent in Kombucha. Kombucha metabolism produces glucose, fructose, small amounts of ethanol, carbon-dioxide, vitamins C, B1 B2, B3, B6, B12, folic acid, diff erent organic acids, mainly acetic, gluconic, L-lactic, glucuronic, enzymes and some antibiotically active compounds, and many others. Beverage also contains most of tea ingredients like tea catechines and caff eine. The beverage has been claimed is considered a prophylactic agent and is considered benefi cial to human health.
Article
Full-text available
Fermentation of pomegranate juice as single or mixed substrate with orange juice, without addition of extra nutrients, using kefir grains is proposed. Sugar consumption and ethanol production were monitored during fermentation, while the formation of lactic acid and the survival of lactic acid bacteria were determined during storage at 4 °C for 4 weeks. The results showed that addition of orange juice improved the ability of kefir grains to ferment pomegranate juice, and increased the survival rates of lactic acid bacteria (LAB) contained in kefir grains during storage. Specifically, 75% cells survived (6.48 log cfu/ml) after 4 weeks of storage in the fermented mixed substrate (24% in plain pomegranate juice). Lactic acid formation was observed in all products, especially in the mixed substrate (1.3-1.9 g/l), indicating metabolic activity during storage. In all cases a low decrease of pH was observed. The results show the possibility to produce low-alcoholic nutritious fruit beverages with potential antioxidant (due to pomegranate constituents) and probiotic properties (due to the probiotic species present in kefir grains). In addition sensorial tests that were conducted showed the consumers acceptance for all the fermented juices.
Article
Full-text available
Sour cherry juices were produced from 5 different cultivars with classic processing technology. Regarding primary juice parameters, high results for dry mass (13.7-18.8 °Brix), sugar-free extract (57.5-80 g/L), total acidity (15.8-23.7 g/L), sorbitol (12.1-21.6 g/L) and minerals were found. Secondary plant metabolites were present in high amounts as well. In the sum, 651-1693 mg/L of polyphenols were found by means of HPLC/PDA. Neochlorogenic acid, 3-coumaroyl-quinic acid, chlorogenic acid, and epicatechin were the predominant polyphenols. The quercetin glycosides ranged from 31-109 mg/L. Anthocyanins were identified as cyanidin-3-(2G-glucosylrutinoside), cyanidin-3-(2 G-xylosylrutinoside), cyanidin-3-glucoside, cyanidin-3-rutinoside, and peonidin-3-rutinoside. A significant decline of the anthocyanin concentrations could be observed during a 6 months storage, which reduced the red colour of the juices drastically. The high polyphenol concentrations were responsible for the high antioxidative capacities of the juices.
Article
Full-text available
The effect of lactic acid bacterial fermentation on sugars, organic acids, bio-transformation of phenolic compounds (anthocyanins and ellagic acid), and antioxidant activity was investigated in pomegranate juice. L. plantarum and L. acidophilus were used as probiotic starter organisms. Both bacteria were able to grow in the juice and their viable cells reached to 3.9×108 CFU/mL after 72 h of fermentation. Fructose and glucose of the juice were significantly consumed by both probiotic starter cultures, and L. plantarum utilized more sugars in comparison with L. acidophilus. Glucose degradation rate was higher than fructose. The concentration of citric acid, as the main acid found in the juice, was significantly reduced by both bacteria through the first 48 h of the process (P L. plantarum. LC/MS analysis of different anthocyanins, revealed that these compounds (except pelargonidin 3-glucoside) were significantly decreased in the pomegranate juice after fermentation. DPPH Radical scavenging studies showed that fermentation of pomegranate juice using selected probiotic starters increased the antioxidant activity significantly (P L. acidophilus improved the antioxidant activity of the juice more extensively than L. plantarum. The results of this study showed that fermentation of pomegranate juice by probiotic bacteria would enhance the health benefits of the juice.
Article
Kombucha is a health-promoting fermented beverage traditionally made by fermenting a sweetened tea with a symbiotic culture of yeast species and acetic acid bacteria. The aim of this work was to develop a beverage using red grape juice as an alternative substrate. Grape juice contains various nutrient elements and phytochemicals, such as polyphenols, which possess a wide range of biological activities. We investigated the chemical characteristics and sensory and antimicrobial activities of the fermented grape juice Kombucha beverage. The pH decreased from 3.95 to 2.9 during the fermentation process and remained fairly constant thereafter, and the acetic acid bacteria and yeast counts in the broth increased up to 6 days of fermentation and subsequently decreased. Phenolic and anthocyanin contents and the antioxidant activity of the fermented beverage were higher after fermentation, with the maximum increase observed on the sixth day of fermentation when values were approximately 2.47- and 1.59-fold higher than pre-fermentation values, respectively, as assessed by 2,2-diphenyl-1-picrylhydrazyl and 2,2′-azino-bis (3-ethylbenzothiazoline-6- sulfonic acid) radical scavenging assays. Fourier transform infrared spectroscopy was used for the qualitative analysis of the grape juice before and after fermentation. Distinct peak variations in the spectral region between 2500 and 1650 cm⁻¹ were observed, which matched the appearance of organic acids and changes in phenolic compounds. Fermented juice Kombucha showed antibacterial activity toward all tested bacteria, which can be primarily ascribed to the increased production of acetic acid, but also to the biosynthesis of other metabolites, during the fermentation process. The 6-day fermented juice was the most appreciated by the taste panel based on the overall quality evaluation; with prolongation of fermentation the fermented juice acquired a distinct sour flavor.
Article
Glucuronic acid-a human detoxifying drug can be found in traditional kombucha which is a sweetened-black tea fermented by symbiotic microflora between yeast and acetic acid bacteria embedded within a microbial cellulose membrane. The main purpose of the study is to obtain the new designed symbiosis from the isolated yeasts and bacterial strains which can produce the high-level glucuronic acid kombucha and avoid unexpected microbial contaminants. The isolation, selection and identification showed the best initial combination ratio between Dekkera bruxellensis KN89 and Gluconacetobacter intermedius KN89 is 4Y (yeast):6A (acetic acid -bacteria) in number of living cell per milliliter which produced 175.8 mg L−1 glucuronic acid in 7-day fermentation (P < 0.05). This study also provides a basic understanding about fermentation kinetics of this symbiosis in order to control and enhance the final product at the critical time point (after 54 hrs of process). The findings of this study are practically relevant in producing a safe and glucuronic acid enriched kombucha.
Article
Three commercial Saccharomyces cerevisiae yeast strains: Viniferm Revelación, Viniferm SV and Viniferm PDM were evaluated for the production of pomegranate wine from a juice coupage of the two well-known varieties Mollar and Wonderfull. Further malolactic fermentation was carried out spontaneously. The same fermentation patterns were observed for pH, titratable acidity, density, sugar consumption, and ethanol and glycerol production. Glucose was exhausted while fructose residues remained at the end of alcoholic fermentation. A high ethanol concentration (10.91±0.27% v/v) in combination with 1.49g/L glycerol was achieved. Citric acid concentration increased rapidly a 31.7%, malic acid disappeared as result of malolactic fermentation and the lactic acid levels reached values between 0.40 and 0.96g/L. The analysis of CIEa parameter and total anthocyanin content highlights a lower degradation of monomeric anthocyanins during winemaking with Viniferm PDM yeast. The resulting wine retains a 34.5% of total anthocyanin content of pomegranate juice blend. Copyright © 2015 Elsevier Ltd. All rights reserved.
Article
Fermentation of sugared tea with a symbiotic culture of acetic acid bacteria and yeast (tea fungus) yields kombucha tea which is consumed worldwide for its refreshing and beneficial properties on human health. Important progress has been made in the past decade concerning research findings on kombucha tea and reports claiming that drinking kombucha can prevent various types of cancer and cardiovascular diseases, promote liver functions, and stimulate the immune system. Considering the widespread reports on kombucha, we recognized the need to review and update the research conducted in relation to kombucha tea, its products and tea fungus. Existing reports have suggested that the protective effects of kombucha tea are as good as those of black tea, however, more studies on kombucha tea and its composition are needed before final conclusions can be made.
Article
The transformation of sucrose into glucose, fructose, gluconic acid, ethanol, and acetic acid was determined during a 60 day tea fungus fermentation. Black tea containing 67.5 g sucrose per litre was inoculated with 10% fermentation broth including the cellulose containing coherent top layer of a previous tea fungus fermentation. The microflora embedded in the cellulose/acetan layer was characterized as a mixed culture of Acetobacter xylinum and Zygosaccharomyces sp., respectively. The yeast cells converted sucrose into glucose and fructose. Fructose was metabolized prior to glucose. The pH value of the kombucha beverage decreased during fermentation from 3.75 to 2.42 as a result of acetic acid and gluconic acid formation. A fermentation balance of the substrates sucrose, glucose, fructose and products ethanol, acetic and gluconic acid and CO2 was calculated based on the carbon-mass (g substrate X number of C-atoms X 12/molecular weight of substrate) as parameter. The total carbon-mass at the start of the fermentation was 30.5 g. The analogous values obtained after 10, 20, 30 and 40 days were 30.7 g, 30.5 g, 28.6 g, and 30.5, respectively. The good stoichiometry implies that all major fermentation products have been accounted for.