Available online at www.sciencedirect.com
Journal of Taibah University for Science 7 (2013) 202–208
Antioxidant activity and viability of lactic acid bacteria in
soybean-yogurt made from cow and camel milk
Amal B. Shori a,b,∗
a
Division of Biotechnology, Institute of Biological Sciences, Faculty of Science, University of Malaya, 50603 Kuala Lumpur, Malaysia
b Ministry of Higher Education, 1153 Riyadh, Saudi Arabia
Received 2 May 2013; received in revised form 31 May 2013; accepted 1 June 2013
Available online 22 June 2013
Abstract
In the present study soybean (Glycine max L.) was included in cow and camel milk during fermentation. The resulting soybeanyogurt was evaluated with respect to the changes of post-acidification, viable cell counts (VCC) of Lactobacillus spp. and
Streptococcus thermophilus, total phenolic content (TPC) and antioxidant activity using 1,1-diphenyl-2-picrylhydrazyl radical
(DPPH) inhibition assay during 21 days of refrigerated storage. The presence of soybean in fresh cow- and camel-milk yogurts did
not affect pH reduction compared to respective plain-yogurt. However, soybean–camel milk yogurt showed significant reduction in
pH (4.05 ± 0.06) compared to plain-yogurt 4.35 ± 0.02 on day 7 of storage. Titratable acidity (TA) increased in soybean–cow milk
yogurt (p < 0.05) but not in soybean–camel milk yogurt as compared with respective plain-yogurt during period of storage. The
presence of soybean in fresh yogurt showed increased (p < 0.05) in Lactobacillus spp. VCC by 10% in cow milk-yogurt and 30% in
camel milk-yogurt compared to respective plain-yogurts. On the other hand, VCC of S. thermophilus was higher (p < 0.05) in the
presence of soybean in cow milk yogurt than in camel milk yogurt. Soybean–camel milk yogurt had 2-folds higher TPC on day 0 and
7 (149.59 ± 1.8 and 111.44 ± 2.8 ␮gGAE/ml respectively) than plain-camel milk yogurt (60.04 ± 0.01 and 55.22 ± 0.01 ␮gGAE/ml
respectively). The highest value of TPC in soybean–cow milk-yogurt was showed on day 21 of storage (43.17 ± 1.2 ␮gGAE/ml).
The antioxidant activity increased (p < 0.05) in the presence of soybean in both cow and camel milk yogurts compared to respective controls. The highest antioxidant activity was shown on day 0 for soybean–cow milk yogurt (61.76 ± 2.2%) and day 7 for
soybean–camel milk yogurt (53.16 ± 0.1%). In conclusion, the addition of soybean in both cow- and camel-milk yogurts enhanced
the viability of LAB and antioxidant activity during refrigerated storage.
© 2013 Taibah University. Production and hosting by Elsevier B.V. All rights reserved.
Keywords: Yogurt; Soybean; S. thermophilus; Lactobacillus spp.; Total phenolic content; Antioxidant activity
1. Introduction
∗ Correspondence address: Division of Biotechnology, Institute of
Biological Sciences, Faculty of Science, University of Malaya, 50603
Kuala Lumpur, Malaysia.
E-mail address: shori [email protected]
Peer review under responsibility of Taibah University.
1658-3655 © 2013 Taibah University. Production and hosting by
Elsevier B.V. All rights reserved.
http://dx.doi.org/10.1016/j.jtusci.2013.06.003
Functional food provides biological and therapeutical properties beyond their basic nutritional value [1],
which incorporate readily into diet food and proposed to
reduce disease risk [2]. Yogurt is considered as a functional food because of its lactic acid bacteria (LAB) that
provide significant therapeutic values during milk fermentation including the highly digestible nutrients [3,4]
as well as the ability to produce various antimicrobial
compounds [5], reduce serum cholesterol [6,7], alleviate lactose intolerance [8], stimulate immune system [9]
and stabilize gut microflora [10].
A.B. Shori / Journal of Taibah University for Science 7 (2013) 202–208
The oxidative damage of cell components such as
proteins, lipids, and nucleic acids one of the important
factors associated with diabetes mellitus, cancers and
cardiovascular diseases [11]. This occurs as a result of
imbalance between the generations of oxygen derived
radicals and the organism’s antioxidant potential [11].
Natural antioxidants from plant ingredients can be used
to control the increase formation of free radicals and
decrease in antioxidant capacity and to replace synthetic
antioxidant activity with side effects such as liver damage
and carcinogenesis [12]. Bioactive peptides derived from
enzymatic hydrolysis and/or microbial protoelytic activities during fermentation of soymilk [13,14] are known
to possess high oxidative inhibitory capacity due to their
ability to scavenge free radicals [15].
Soybean (Glycine max L.) is generally recognized
as a functional food and one of the most important
legumes consumed worldwide. It was regarded as high
source of protein, fiber, vitamins and minerals [16,17].
It has a variety of biologically active phytochemicals,
e.g. isoflavones, coumestrol, phytate, saponins, lecithin,
phytosterols and vitamin E, that provide potential health
benefits such as antioxidant properties [18], reduce the
risk of heart diseases, lowering cholesterol [19] and
improve body composition such as increase of fat-free
mass and decrease of abdominal fat mass [20]. Therefore, the current study focuses on using additive such
as soybean to improve the antioxidant and the viability
of lactic acid bacteria in cow- and camel-milk yogurts
during refrigerated storage.
203
2.2. Soybean water extracts preparation
The water extraction of soybean was performed
according to the method described by Shori and Baba
[21].
2.3. Preparation of starter culture
The starter culture preparation was carried out using
the method described by Shori and Baba [22].
2.4. Preparation of yogurt
The two groups of bio-yogurt made from cow or
camel milk both in the presence and absence of soybean water extract were prepared as described by Shori
and Baba [22].
2.5. Preparation of yogurt water extract
The yogurt water extract was performed as described
by Shori and Baba [23].
2.6. Measurement of pH and titratable acidity (TA)
The pH of yogurt was measured by using a digital
Metler Toledo 320 pH meter. Titratable acidity (TA)
expressed as percentage of lactic acid and determined
as described by Shori et al. [24].
2. Materials and methods
2.7. Viable cell counts (VCC) of microbial
2.1. Materials and chemicals
2.7.1. Enumeration of Lactobacillus spp. and S.
thermophilus
Lactobacillus spp. and S. thermophilus were enumerated as described by Shori and Baba [25].
Soybean was purchased from local store and ground
to powder form. Homogenized and pasteurized full
cream cow milk (Dutch Lady, Malaysia) and camel
milk (Al-Turath, Saudi Arabia) were purchased from
supermarket. Other materials including in this present
study were Commercially available direct vat set (DVS)
yogurt starter culture powder used in yogurt preparation consist of a mixture of Lactobacillus acidophilus
LA-5, Bifidobacterium Bb-12, Lactobacillus casei LC01, Streptococcus thermophilus Th-4 and L. delbrueckii
spp. Bulgaricus in the ratio of 4:4:1:1:1. Chemicals
such as 1,1-diphenyl-2-picrylhydrazyl radical (DPPH),
Folin–Ciocalteu reagent, De Man Rogosa and Sharpe
(MRS) agar, M17 agar, buffered peptone water and other
chemicals were purchased from Sigma Chemical Company (St. Louis, MO, USA).
2.8. Total phenolic content assay
The total phenolic content (TPC) was determined
according to Shetty et al. [26].
2.9. Measurement of antioxidant activity (DPPH)
inhibition assay
The antioxidant activity was determined by measuring the free radical scavenging ability of yogurt water
extract using DPPH inhibition assay as described by
Shetty et al. [27].
204
A.B. Shori / Journal of Taibah University for Science 7 (2013) 202–208
Fig. 2. Changes in bacterial counts of Lactobacillus spp. (106 cfu/ml)
during refrigerated (4 ◦ C) storage. plain-cow milk-yogurt (control),
soybean–cow milk-yogurt,
plain-camel milk-yogurt (control),
and soybean–camel milk-yogurt respectively. Values are presented
as mean ± SEM (n = 3).
Fig. 1. Changes in a) pH and b) titratable acidity (TA) during
refrigerated (4 ◦ C) storage.
plain-cow milk-yogurt (control),
soybean–cow milk-yogurt,
plain-camel milk-yogurt (control), and
soybean–camel milk-yogurt respectively. Values are presented as
mean ± SEM (n = 3).
2.10. Statistical analysis
The experiments were carried out in three different batches of yogurts (n = 3). Data were expressed
as mean ± S.M.E (standard mean error). The statistical
analysis was performed using one way analysis of variance (ANOVA, SPSS 17.0), followed by Duncan’s post
hoc test for mean comparison. The criterion for statistical
significance was p < 0.05.
3. Results and discussions
3.1. Post-acidification of yogurt
In the present study, the pH of fresh cow- and camelmilk yogurts (0 day) in the presence of soybean was
not significant different compared to plain-cow and
-camel milk yogurt respectively (Fig. 1a). However,
soybean–camel milk yogurt showed sustained reduction
in pH during 21 days of refrigerated storage (4.05–4.04)
with no significant differences compared to plain-camel
milk yogurt except on day 7 of storage (4.05; p < 0.05).
On the other hand, the presence of soybean in cow
milk yogurt did not affect pH reduction compared to
the absence during period of storage. In contrast, TA
increased during refrigerated storage (Figure 1,b) which
enhanced more (p > 0.05) in present of soybean in
both cow and camel milk-yogurts compared to respective plain-yogurts. However, TA showed reduction in
soybean–cow milk-yogurt (0.93 ± 0.05%; p > 0.05) on
day 21 of refrigerated storage. Post-acidification of
yogurt occurred during refrigeration and this could be
explained by the residual metabolic activity of yogurt
bacteria. The activity of β-galactosidase released by the
LAB to cleave lactose is still active even at refrigerated
storage temperature (0–5 ◦ C) [28]. This is contribute to
the accumulation of lactic acid, acetic acid, citric acid,
butyric acid, acetaldehyde and formic acid produced by
yogurt starter culture as metabolic by-products [29–31].
The sustained reduction of pH in camel milk yogurts
could be attributed to the ability of milk to resist changes
in pH during fermentation [32,33] even in presence of
acidic matters due to inherent high buffering capacity of
milk [32].
3.2. Viable cell counts of Lactobacillus spp. and
S. thermophilus
The presence of soybean in fresh cow or camel
milk-yogurts showed increased (p < 0.05) in VCC of
Lactobacillus spp. to about 10% and 30% respectively as
compared to respective plain-yogurt (Fig. 2). However,
VCC of Lactobacillus spp. showed significant reduction from 11.02 × 106 cfu/ml to 2.87 × 106 cfu/ml for
soybean–cow milk yogurt and from 43.75 × 106 cfu/ml
to 8.57 × 106 cfu/ml for soybean–camel milk yogurt
during 21 days of storage. On the other hand, the
addition of soybean in camel milk yogurt did not
affect the VCC of S. thermophilus except on day 0
and 14 of storage whereas the presence of soybean
in cow milk yogurt increased (p < 0.05) S. thermophilus VCC overall storage period (Fig. 3). VCC of
A.B. Shori / Journal of Taibah University for Science 7 (2013) 202–208
205
Fig. 3. Changes in bacterial counts of Streptococcus thermophilus
plain-cow milk(108 cfu/ml) during refrigerated (4 ◦ C) storage.
soybean–cow milk-yogurt,
plain-camel
yogurt (control),
milk-yogurt (control), and soybean–camel milk-yogurt respectively.
Values are presented as mean ± SEM (n = 3).
Fig. 4. Changes in total phenolic content (␮g/ml) in yogurt during
refrigerated (4 ◦ C) storage.
plain-cow milk-yogurt (control),
soybean–cow milk-yogurt,
plain-camel milk-yogurt (control), and
soybean–camel milk-yogurt respectively. Values are presented as
mean ± SEM (n = 3).
S. thermophilus in fresh soybean–cow and camel milk
yogurts were 6.03 × 108 cfu/ml and 4.25 × 108 cfu/ml
respectively whereas plain-cow and -camel milk yogurt
showed 2.4 × 108 cfu/ml and 3.1 × 108 cfu/ml S. thermophilus VCC respectively. The highest VCC of S.
thermophilus was shown on day 7 (30.26 × 108 cfu/ml)
and 14 (11.24 × 108 cfu/ml) of storage for soybean–cow
and camel milk yogurts respectively. Prolonged storage to 21 days resulted in reduction in S. thermophilus
VCC for all yogurts (Fig. 3). Yogurts containing live
cultures confer health benefits to the host when they are
consumed in appropriate quantity [34]. Thus, it is necessary for most of these live cultures to survive during
their shelf life prior being consumed. Plant ingredients
such as guar gum and cocoa or compound from plant
(dextrose) were found to enhance the viability of probiotics in dairy products [33]. In the present study, the
inclusion of soybean in yogurt increased LAB counts
compared to plain-yogurt. Farnworth et al. [35] found
that the growth of lactobacilli was more extensive in fermented soy beverage than fermented milk. However, the
increased concentration of organic acids is one of the
important factors that can dramatically affect bacterial
growth. Thus the reduction of Lactobacillus spp. VCC
during storage for both types of yogurt could be associated with the post-acidification which causes further
reduction in pH [36,37]. In addition, the increased hydrogen peroxide produced by yogurt bacteria may affect the
survival of Lactobacillus spp. [38]. The further reduction of Lactobacillus spp. VCC in camel milk-yogurts
than in cow milk-yogurts observed in our study (Fig. 2)
may not only occur as a result of pH decline but also
due to higher antibacterial activities of camel milk than
cow milk [39]. This is in agreement to previous report
by Shori and Baba [25] who stated that faster reduction of Lactobacillus spp. VCC in herbal–camel milk
yogurt than in herbal–cow milk yogurt. The increase in
the VCC of S. thermophilus in both types of yogurt during the first week of refrigerated storage is in agreement
to previous studies [25,40,41]. The reduction in S. thermophilus by day 14 and 21 of storage for soybean–cow
and camel milk yogurt respectively may be attributed to
the accumulation of organic acids [30] and waste products produced by bacterial activity such as hydrogen
peroxide [36].
3.3. Total phenolic content (TPC)
The total phenolic content (TPC) in yogurt made from
cow or camel milk is shown in (Fig. 4). The presence of
soybean in cow milk-yogurt showed no significant differences in TPC compared to plain-yogurt on 0 and 7
days of storage. However, prolonged refrigerated storage
increased (p < 0.05) TPC for soybean–cow milk yogurt
(39.96 ± 0.7 and 43.17 ± 1.2 ␮gGAE/g) compared to
plain-yogurt (33.53 ± 1.0 and 32.33 ± 1.0 ␮gGAE/g)
on 14 and 21 days respectively. On the other
hand, the presence of soybean in camel milkyogurt showed 2-folds higher TPC (149.59 ± 1.8 and
111.44 ± 2.8 ␮gGAE/g) than plain-camel milk yogurt
(60.04 ± 0.01 and 55.22 ± 0.01 ␮gGAE/g) on day 0
and 7 of storage respectively. Prolonged storage to 21
days decreased (p > 0.05) TPC in soybean–camel milk
yogurt to (91.76 ± 1.8 ␮gGAE/g). The differences in
TPC between cow and camel milk yogurts both in the
presence and absence of soybean could be explained by
the degradation of milk proteins during proteolytic activity of yogurt bacteria resulting in the release of some
phenolic compounds such as phenolic acids, flavonoids
and isoflavonoids present in soybean seeds attached to
milk protein [42]. Thus higher VCC of Lactobacillus
spp. in soybean–camel milk yogurt than soybean–cow
206
A.B. Shori / Journal of Taibah University for Science 7 (2013) 202–208
4. Conclusion
Fig. 5. Changes in antioxidant activity in yogurt (inhibition %) during refrigerated (4 ◦ C) storage. plain-cow milk-yogurt (control),
soybean–cow milk-yogurt,
plain-camel milk-yogurt (control), and
soybean–camel milk-yogurt respectively. Values are presented as
mean ± SEM (n = 3).
The addition of soybean enhanced the postacidification in cow milk yogurt but not in camel milk
yogurt. On the other hand, soybean–camel milk yogurt
showed higher TPC than soybean–cow milk yogurt during 21 days refrigerated storage. The viability of LAB
and antioxidant activity were improved in the presence
of soybean in both types of yogurt. Higher Lactobacillus spp. VCC was showed in soybean–camel milk yogurt
than soybean–cow milk yogurt while the latter showed
higher S. thermophilus VCC than the former. Thus, soybean may be used to support the survival of LAB and
antioxidant activity not only in cow milk yogurt but also
in camel milk yogurt during refrigerated storage.
Conflict of interest
The authors have no conflicts of interest to disclose.
milk yogurt (Fig. 2) could explain higher TPC in the
former than the latter. Lactobacilli generally considered
to be more proteolytically active than the streptococci
during milk fermentation and storage [4]. In addition,
the degradation of milk proteins itself may resulted in the
release of phenolic amino acids and non-phenolic compounds such as sugars and proteins which may interfere
during total phenolic evaluation [43].
3.4. Antioxidant activity
The presence of soybean during yogurt formation increased (p < 0.05) the antioxidant activities
in both cow and camel milk-yogurts (61.76 ± 3.3%
and 53.16 ± 0.9% respectively) compared to respective plain-yogurts (26.41 ± 07% and 15.44 ± 1.2%
for plain-cow and -camel milk respectively; Fig. 5).
Soybean–camel milk yogurt showed the highest antioxidant activity on day 7 of storage (67.59 ± 1.4%) followed
by reduction (p > 0.05) to 61.56 ± 1.4% on day 21 of
storage. The antioxidant activity of soybean–cow milk
yogurt showed significant reduction during 21 days of
refrigerated storage to 35.29 ± 1.0%. Phenolic content
is the most influential factor to antioxidant activity [44].
Soybean has been previously reported to show antioxidant activity properties associated to isoflavones and
polyphenolic compounds [45,46]. Additionally, milk
protein proteolysis [47] and organic acids production
[48] as a result of microbial metabolic activity during fermentation and refrigerated storage could be other sources
of antioxidant activities.
References
[1] C.M. Hasler, Functional foods: benefits, concerns and challenges
– a position paper form the American Council on Science and
Health, Journal of Nutrition 132 (2002) 3772–3781.
[2] N.D. Buckley, C.P. Champagne, A.I. Masotti, L.E. Wagar, T.A.
Tompkins, J.M. Green-Johnson, Harnessing functional food
strategies for the health challenges of space travel – fermented
soy for astronaut nutrition, Acta Astronautica 68 (2011) 731–738.
[3] H.C. Deeth, A.Y. Tamime, Yogurt, nutritive and therapeutic
aspects, Journal of Food Protection 44 (1981) 78–86.
[4] V. Marshal, The microflora and production of fermented milks,
Progress in Industrial Microbiology 23 (1986) 1–44.
[5] R. Temmerman, B. Pot, G. Huys, J. Swings, Identification and
antibiotic susceptibility of bacterial isolates from probiotic products, International Journal of Food Microbiology 81 (2002) 1–10.
[6] M. Desmazeaud, Les bactéries lactiques dans l’alimentation
humaine: Utilisation et innocuité, Cahiers Agricultures 5 (1996)
331–343.
[7] M.S. Jackson, A.R. Bird, A.I. Mc-Orist, Comparison of two selective media for the detection and enumeration of lactobacilli in
human faeces, Journal of Microbiological Methods 51 (2002)
313–321.
[8] M. De Vrese, A. Steglman, B. Richter, S. Fenselau, C. Laue,
J. Scherezenmeir, Probiotics – compensation for lactase insufficiency, American Journal of Clinical Nutrition 73 (2001)
421–429.
[9] E. Isolauri, Y. Sütas, P. Kankaanpää, H. Arvilommi, S. Salminen, Probiotics: effects of immunity, American Journal of Clinical
Nutrition 73 (2001) 444–450.
[10] G.R. Gibson, J.M. Saveedra, S. Mac-Farlane, G.T. Mac-Farlane,
Probiotics and intestinal infections, in: R. Fuller (Ed.), Probiotic.
2: Applications and Practical Aspects, Chapman & Hall, New
York, 1997, pp. 10–39.
[11] R. Rahimi, S. Nikfar, B. Larijani, M. Abdollahi, A review on
the role of antioxidants in the management of diabetes and its
complications, Biomedicine and Pharmacotherapy 59 (7) (2005)
365–373.
A.B. Shori / Journal of Taibah University for Science 7 (2013) 202–208
[12] S. Meenakshi, D. Manicka Gnanambigai, S. Tamil mozhi, M.
Arumugam, T. Balasubramanian, Total flavanoid and in vitro
antioxidant activity of two seaweeds of Rameshwaram coast,
Global Journal of Pharmacology 3 (2) (2009) 59–62.
[13] E. Apostolidis, Y.I.I. Kwon, K. Shetty, Potential of cranberrybased herbal synergies for diabetes and hypertension management, Asia Pacific Journal of Clinical Nutrition 15 (2006)
433–441.
[14] R. Darmawan, N.A. Bringe, E.G. Mejia, Antioxidant capacity
of alcalase hydrolysates and protein profiles of two conventional
and seven low glycinin soybean cultivars, Plant Foods for Human
Nutrition 65 (3) (2010) 233–240.
[15] R.J. Elias, S.S. Kellerby, E.A. Decker, Antioxidant activity of proteins and peptides, Critical Reviews in Food Science and Nutrition
48 (5) (2008) 430–441.
[16] D. Malencic, M. Popovic, J. Miladinovic, Phenolic content and
antioxidant properties of soybean (Glycine max (L.) Merr.) seeds,
Molecules 12 (2007) 576–581.
[17] B.J. Xu, S.K.C. Chang, A comparative study on phenolic
profiles and antioxidant activities of legumes as affected by
extraction solvents, Journal of Food Science 72 (2) (2007)
S159–S166.
[18] A.K. Tripathi, A.K. Misra, Soybean – a consummate functional
food: a review, Journal of Food Science and Technology 2 (2005)
42–46.
[19] S. Goodin, F. Shen, W.J. Shih, N. Dave, M.P. Kane, P. Medina,
G.H. Lambert, J. Aisner, M. Gallo, R.S. DiPaola, Clinical, biological activity of soy protein powder supplementation in healthy
male volunteers, Cancer Epidemiology Biomarkers and Prevention 16 (4) (2007) 829–833.
[20] E. Riesco, M. Aubertin-Leheudre, M.L. Maltais, M. Audet,
I.J. Dionne, Synergic effect of phytoestrogens and exercise
training on cardiovascular risk profile in exercise-responder
postmenopausal women: a pilot study, Menopause 17 (2010)
1035–1039.
[21] A.B. Shori, A.S. Baba, Antioxidant activity and inhibition of
key enzymes linked to type-2 diabetes and hypertension by
Azadirachta indica-yogurt, Journal of Saudi Chemical Society
(2011), http://dx.doi.org/10.1016/j.jscs.2011.04.006.
[22] A.B. Shori, A.S. Baba, Comparative antioxidant activity,
proteolysis and in vitro ␣-amylase and ␣-glucosidase inhibition of Allium sativum-yogurts made from cow and
camel milk, Journal of Saudi Chemical Society (2011),
http://dx.doi.org/10.1016/j.jscs.2011.09.014.
[23] A.B. Shori, A.S. Baba, Cinnamomum verum improved the functional properties of bioyogurts made from camel and cow milks,
Journal of the Saudi Society of Agricultural Sciences 10 (2) (2011)
101–107.
[24] A.B. Shori, A.S. Baba, P.F. Chuah, The effects of fish collagen on the proteolysis of milk proteins, ACE inhibitory activity
and sensory evaluation of plain- and Allium sativum-yogurt,
Journal of the Taiwan Institute of Chemical Engineers (2013),
http://dx.doi.org/10.1016/j.jtice.2013.01.024 (in press).
[25] A.B. Shori, A.S. Baba, Viability of lactic acid bacteria and
sensory evaluation in Cinnamomum verum and Allium sativumbio-yogurts made from camel and cow milk, Journal of the
Association of Arab Universities for Basic and Applied Sciences
12 (1) (2012) 50–55.
[26] K. Shetty, O.F. Curtis, R.E. Levin, R. Witkowsky, W. Ang, Prevention of verification associated with in vitro shoot culture of
oregano (Origanum vulgare) by Pseudomonas spp., Journal of
Plant Physiology 147 (1995) 447–451.
207
[27] S. Shetty, S. Udupa, L. Udupa, Evaluation of antioxidant and
wound healing effects of alcoholic and aqueous extract of Ocimum sanctum Linn. in rats, Evidence-Based Complementary and
Alternative Medicine 5 (2008) 95–101.
[28] K. Kailasapathy, K. Sultana, Survival and ␤-galactosidase activity
of encapsulated and free Lactobacillus acidophilus and Bifidobacterium lactis in ice-cream, Australian Journal of Dairy
Technology 58 (2003) 223–227.
[29] L. Novak, P. Loubiere, The metabolic network of Lactococcus
lactis: distribution of 14 C-labeled substrates between catabolic
and anabolic pathways, Journal of Bacteriology 182 (4) (2000)
1136–1143.
[30] H.M. Ostlie, J. Treimo, J.A. Narvhus, Effect of temperature on
growth and metabolism of probiotic bacteria in milk, International
Dairy Journal 15 (2003) 989–997.
[31] O. Adolfsson, S.N. Meydani, R.R. Russell, Yogurt and gut function, American Journal of Clinical Nutrition 80 (2) (2004) 45–56.
[32] F. Salaün, B. Mietton, F. Gaucheron, Buffering capacity of dairy
products, International Dairy Journal 15 (2) (2005) 95–109.
[33] C.S. Ranadheera, C.A. Evans, M.C. Adams, S.K. Baines, In vitro
analysis of gastrointestinal tolerance and intestinal cell adhesion
of probiotics in goat’s milk ice cream and yogurt, Food Research
International 49 (2012) 619–625.
[34] M. Saxelin, R. Korpela, A. Mayra-Makinen, Introduction: classifying functional dairy products, in: T. Mattila-Sandholm, M.
Saarela (Eds.), Functional Dairy Products, Woodhead Publishing
Limited, Cambridge, England, 2003, pp. 1–16.
[35] E.R. Farnworth, I. Mainville, M.-P. Desjardins, N. Gardner, I.
Fliss, C. Champagne, Growth of probiotic bacteria and bifidobacteria in a soy yogurt formulation, International Journal of Food
Microbiology 116 (2007) 174–181.
[36] N.P. Shah, Probiotic bacteria: Selective enumeration and survival
in dairy products, Journal of Dairy Science 83 (2000) 894–907.
[37] E.A. Eissa, A.A. Yagoub, E.E. Babiker, I.A. Mohamed Ahmed,
Physicochemical, microbiological and sensory characteristics of
yoghurt produced from camel milk during storage, Electronic
Journal of Environmental Agricultural and Food Chemistry 10
(6) (2011) 2305–2313.
[38] A. Talwalkar, K. Kailasapathy, A review of oxygen toxicity in
probiotic yoghurts: influence on the survival of probiotic bacteria and protective techniques, Comprehensive Reviews in Food
Science and Food Safety 3 (2004) 117–124.
[39] Anonymous, Composition of camel milk. At: www.fao.org
(accessed 24.12.03).
[40] G.A. Birollo, J.A. Reinheimer, C.G. Vinderola, Viability of lactic acid microflora in different types of yogurt, Food Research
International 33 (2000) 799–805.
[41] O.N. Donkor, A. Henriksson, T. Vasiljevic, N.P. Shah, Effect of
acidification on the activity of probiotics in yoghurt during cold
storage, International Dairy Journal 16 (2006) 1181–1189.
[42] P. McCue, K. Shetty, Phenolic antioxidant mobilization during
yogurt production from soymilk using Kefir cultures, Process
Biochemistry 40 (2005) 1791–1797.
[43] E.A. Ainsworth, K.M. Gillespie, Estimation of total phenolic
content and other oxidation substrates in plant tissues using
Folin–Ciocalteu reagent, Nature Protocols 2 (2007) 875–877.
[44] Z. Sroska, W. Cisowski, Hydrogen peroxide scavenging, antioxidant and anti-radical activity of some phenolic acids, Food and
Chemical Toxicology 41 (2003) 8–753.
[45] J.A. Kim, W.S. Jung, S.C. Chun, C.Y. Yu, K.H. Ma, J.G. Gwag,
I.M. Chung, A correlation between the level of phenolic compounds and the antioxidant capacity in cooked-with-rice and
208
A.B. Shori / Journal of Taibah University for Science 7 (2013) 202–208
vegetable soybean (Glycine max L.) varieties, European Food
Research and Technology 224 (2006) 259–270.
[46] M. Slavin, Z. Cheng, M. Luther, W. Kenworthy, L. Yu,
Antioxidant properties and phenolic, isoflavone, tocopherol and
carotenoid composition of Maryland-grown soybean lines with
altered fatty acid profiles, Food Chemistry 114 (1) (2009) 20–27.
[47] A. Lourens-Hattingh, B.C. Viljoen, Yogurt as probiotic carrier
food, International Dairy Journal 11 (2001) 1–17.
[48] I. Correia, A. Nunes, I.F. Duarte, A. Barros, I. Delgadillo,
Sorghum fermentation followed by spectroscopic techniques,
Food Chemistry 90 (2005) 853–859.