Indian J Dairy Sci 74(2): 124-130

https://doi.org/10.33785/IJDS.2021.v74i02.004

RESEARCH ARTICLE

Process optimization of fortified sweetened milk kefir

Kavita K Solanki and Bikash C Ghosh

Received: 09 May 2020 / Accepted: 31 December 2020 / Published online: 07 June 2021
© Indian Dairy Association (India) 2021

Abstract: Kefir is an acidic-alcoholic fermented milk product. Introduction

Regular consumption of kefir is helpful in relieving intestinal
disorders, reducing flatulence, and creating healthier digestive Kefir is a fermented milk product prepared by incubating milk
system. An attempt was made to optimise the process to produce with either kefir grains (a group of microorganisms held together
fortified sweetened milk kefir. Kefir was prepared using kefir grains by a polysaccharide framework i.e., Kefiran) or kefir starter culture
with sugar (6, 8 and 10%), fibres (inulin, oat, and soya, each 3%) (Satir and Guzel-Seydim, 2016). Kefir differs from other fermented
and stabilizer (0.1% pectin). Addition of 6% sugar showed milk products in a way that is not a simple consequence of the
significantly (p<0.05) higher body and texture scores with no metabolic action of a single microbial species but a blended
significant (p>0.05) difference in flavour, colour and appearance microflora i.e., 66% bacilli, 16% streptococci, and 18% yeasts
when compared to kefir made with 8 and 10% sugar. Similarly, (Farnworth, 2003). Enthusiasm has evolved for the development,
overall acceptability was highest in kefir made with 6% sugar. production, and utilization of kefir since its beginning, owing to
Firmness in kefir was highest made with 6% sugar, followed by 8 its immense therapeutic benefits on the immune system, the
and then 10% sugar. Among the three fibers, addition of 3% gastrointestinal system and the digestion of cholesterol (Tamai
inulin showed significantly (p<0.05) better sensory attributes et al. 1996). Moreover, anti-cancer, anti-bacterial and anti-fungal
when compared to kefir added with soya and oat fibre. Acidity of properties have been exhibited in vitro, animals or human models
inulin added kefir was lowest among soya and oat fibre added (De Moreno de LeBlanc et al. 2007). Additionally, kefir cultures
kefirs which was optimum. Kefir prepared with soya fibre showed can be linked to promote food safety by restraining coliforms
significantly (p<0.05) higher acidity than other two samples. No and several pathogens (Van Wyk et al. 2011).
significant (p>0.05) difference was observed in pH among all
kefir samples. Firmness and consistency increased significantly As kefir has a slightly acidic taste, yeasty and tangy flavour,
(p<0.05) with the addition of inulin. An acceptable quality fortified sweetening of kefir will make the taste milder, improve flavour
sweetened milk kefir can be prepared with 0.1% pectin, 6% sugar and overall acceptability which will be more relished by the Indian
and 3% inulin as dietary fibre for improved health benefit. populace. In eastern part of India, dahi is used as mistidoi/dahi
by adding sweetener such as jaggery which lends a caramelized
Keywords: Colour, Dietary fibre, Flavour, Health benefit, flavour and colour to the dahi. Sweetening will make the kefir a
Sweetened milk kefir product like mistidahi. Cool sweet milk kefir will be a thirst
quenching and refreshing product with prickly sensation.
Sweetness of the kefir will provide an exotic enrichment to the
taste buds. Yet, no attempt has been made so far to prepare
sweetened milk kefir and to evaluate the microbial behaviour of
ICAR- National Dairy Research Institute, Adugodi, Bengaluru- 560 kefir grains in the presence of sugar.
030, India
Milk and most milk products are devoid of dietary fibre, but
there is a growing awareness among consumers about the
physiological benefits of fibre fortified milk products. Dietary
fibres impart some basic functional characteristics like water
holding capacity, viscosity, water swelling capacity, fat binding
Bikash C Ghosh () capacity, antioxidant properties etc. (Elleuch et al. 2011) and
ICAR- National Dairy Research Institute, Adugodi, Bengaluru- 560 improving sensory characteristics and shelf- life of the product.
030, India Various published reports have demonstrated that there are
Email: ghosgoga@hotmail.com
numerous therapeutic benefits related with the consumption of
dietary fibre, including lower risk of heart diseases, diabetes,

124
 Indian J Dairy Sci 74(2): 124-130

obesity, and a few types of malignancy (Mann and Cummings 20 inch). After retrieving the kefir grains, the products were then
2009). Addition of inulin has shown that it can attenuate the filled in polypropylene cups and kept for maturation for 24 h at 6-
cholesterol in blood plasma (Roberfroid, 2005) and improves 8ºC. Thereafter, the product was stored in the refrigerator.
calcium, magnesium, and iron absorption (Bosscher et al. 2003).
Addition of oat fibres is linked with depletion of post-prandial Sensory evaluation
blood glucose and insulin responses (Wood et al. 1994), higher
transport of bile acids towards lower portions of the gut and Sensorial assessment of the milk kefir was carried out by an expert
higher discharges of bile acids (Dongowski et al. 2005) or panel of minimum five judges to judge the kefir samples on a 9-
reduction of serum cholesterol levels (Hecker et al. 1998). Yogurt point hedonic scale (9=like extremely; 1=dislike extremely) at room
fortified with soya is advantageous in reducing cholesterol levels temperature. Duo-trio tests were used to determine a candidate’s
(Crouse et al. 1999), blood pressure and to alleviate indications ability to detect differences among similar products with different
of menopause and osteoporosis (Messina et al. 2004). To know ingredients for selection of Judges.
the beneficial effects of kefir consumption, an attempt was made
Physico-chemical analysis
to optimize the process for preparation of fortified sweetened
milk kefir. pH
Materials and Methods The pH of kefir samples was measured directly by inserting the
electrode into the sample followed by recording of reading.
Raw materials and ingredients
Titratable acidity
Fresh whole and skim milk were procured from the Experimental
Dairy Plant of ICAR- National Dairy Research Institute, Bengaluru The acidity of kefir samples was measured as per the method of
(India). Kefir grains were obtained from U.S. Food grade High AOAC947.05 (2012) for milk. The sample was well mixed, and 10
methoxy pectin obtained from M/s Hi Media laboratories Pvt. g of sample was taken in a beaker. Phenolphthalein indicator of 2-
Ltd. Refined crystalline cane sugar from local market, Dietary 3 drops was added and titrated against 0.1 N NaOH till the first
soya fibre (Fimbrim® from M/s Solae Company, U.S.), oat fibre appearance of faint pink colour. The acidity was expressed as %
(Vitacel® HF- 600® from M/s J. Rettenmair and Sohne Gmbh, lactic acid by weight.
Germany) and inulin (from M/s DKSH India Pvt. Ltd., Bangalore,
India) were procured. Textural analysis

Activation of kefir grains Textural properties such as firmness, consistency, index of

viscosity and stickiness were determined using TA-XT Plus
Kefir grains were activated according to the technique adopted Texture Analyser (Stable Microsystem, UK) with P/25 cylindrical
by Angulo et al. (1993). Following each incubation, straining of probe. At 6-8°C, textural properties of kefir samples were
the fermented product was done through nylon sieve (mesh size: measured using 200 ml kefir in a 250 ml beaker. The probe travelled
1/20 inch) to retrieve the kefir grains which were then washed at a speed of 1.0 mm/s up to 10 mm distance into the kefir sample
with sterile distilled water prior to next inoculation. This process from the surface and then returned to the original position
was repeated 4-5 times until the desirable kefir flavour was generating force-time curve. The positive peak of the curve gave
achieved. firmness (Newton), the negative peak gave stickiness (Newton),
the area of positive peak gave consistency (Newton-second)
Preparation of fortified sweetened milk kefir and the area of negative peak gave index of viscosity (Newton-
second).
Fresh raw milk was standardized to 3% fat, preheated at 50-60°C
and homogenized in two stage (first stage- 2500 psi, second stage- Statistical analysis
500 psi) homogenizer. All the additives were added on milk basis
into the milk after homogenization and before final heat treatment. The data were subjected to analysis of variance (ANOVA) using
During optimization process, first pectin (0.1%) and sugar (6, 8 IBM SPSS statistics 23 software. Results of triplicate trials were
and 10%) were mixed and then added to standardized milk followed used for statistical analysis.
by addition of fibres (inulin, oat, and soya fibre). Milk was heated
to 90-92°C for 10 minutes with intermittent stirring followed by Results and Discussion
cooling (28-30°C) and filtration to remove any coagulated particles.
Kefir grains were inoculated to the milk at a level of 4 g/L of milk Effect of sugar addition on sensory attributes of milk kefir
and incubated at 30ºC for about20-24 h in B.O.D incubator till the
titratable acidity had reached to 1% lactic acid. The product was All sugar (6, 8 and 10%) added kefir samples scored higher for
thoroughly stirred and sieved through nylon sieve (mesh size: 1/ flavour as compared to control (Fig. 1 a). The most notable

125
Indian J Dairy Sci 74(2): 124-130

Fig. 1Effect of sugar addition on sensory attributes of milk kefir

function of sugar in food is its sweet taste. Sweet taste serves as Effect of sugar addition on pH and acidity of milk kefir
a sensory cue for source of pleasure. Body and texture score of
kefirs with 6% sugar was significantly (p<0.05) higher than other No significant (p>0.05) difference in pH and acidity was observed
three kefir samples (Fig. 1 b). Sugar affected the physical between the control and 6% sugar added kefir. Whereas kefir
characteristics of kefir to a significant degree. It provided solids with 8 and 10% sugar showed significantly (p<0.05) lower acidity
which impacted the mouthfeel and texture of kefir as reported by and higher pH than the control and kefir with 6% sugar (Table 1),
Spillane (2006) for many fermented products. No significant making them less preferred to other kefir samples. Sugar acts as
(p>0.05) difference was observed in colour and appearance among a substrate for lactic acid bacteria and yeast species in kefir grains
all kefirs (Fig. 1 c). Overall acceptability score was maximum for and is responsible for development of acidity during the
kefir with 6% sugar followed by control, 8 and 10% sugar added fermentation. The amount of acidity present depends upon the
kefir, respectively (Fig. 1 d). Akter et al. (2010) evaluated the concentration of sugar and incubation time. Yeasts are recognized
different levels of sugar (8, 10, 12 and 14%) on qualitative in playing a key role in the preparation of fermented dairy
characteristics of mistidahi (Sweet Yoghurt) and found that 10 products, where they provide essential growth nutrients such as
and 12% sugar levels obtained more organoleptic score than amino acids and vitamins, alter pH, secrete ethanol, and produce
those of 8 and 14%. So, the concentration of sugar affects the CO2 (Farnworth, 2003). Hence, lower acidity was observed in 8
characteristics of the final fermented product - higher amount is and 10% sugar added kefir. Ghosh and Rajorhia (1990) also found
detrimental to lactic acid bacteria and lower one does not change similar results in mistidahi and stated that higher concentration
the original sour flavour. Similarly, in the present study an optimum of sugar showed inhibitory effect in the mistidahi. The activity
6% sugar produced the best kefir when compared to control, 8% of the Lactobacillus cultures was greatly affected with the
and 10% sugar. increase in sucrose concentration which alters morphology by
elongating and distorting the cell.

126
 Indian J Dairy Sci 74(2): 124-130

Consistency (N-s)
3
c

2
b b
a

S
ol

6%

8%
tr

%
on

10
C

Fig. 2 Effect of sugar addition on textural properties of milk kefir

Effect of sugar addition on textural properties of milk kefir optimum pH and acidity and better textural properties, it was
selected for further optimization of dietary fibre.
Firmness was significantly (p<0.05) higher for kefir with 6% sugar
as compared to other kefir samples (Fig. 2 a). Kefir with 6% sugar Effect of dietary fibres incorporation on sensory attributes of
showed highest firmness, followed by 8 and 10% sugar added sweetened milk kefir
kefir and then control kefir (Fig. 2 a). Kefir with 6% sugar showed
the highest consistency among all kefir samples. Kefir with 8 and The effects of dietary fibre incorporation on the sensory attributes
10% sugar showed significantly (p<0.05) higher consistency as of kefir are displayed in Fig. 3. Six percent sugar was added in all
compared to control kefir (Fig. 2 b). Similarly, kefir with 6% sugar samples. Control sample was added with sugar but without
exhibited significantly (p<0.05) higher index of viscosity among dietary fibre. Significantly (p<0.05) higher flavour was observed
the four types of kefir (Fig. 2 c). Stickiness was the highest in in inulin added kefir among four samples (Fig. 3 a). Soya fibre
kefir with 6% sugar, followed by with 8, 10% sugar and control, added kefir showed significantly (p<0.05) lower flavour than other
respectively (Fig. 2 d). Textural properties of kefir were improved kefirs (Fig. 3 a). The body and texture of kefir with inulin was the
with the addition of sugar due to increase total solids content in highest among all kefirs (Fig. 3 b). Inulin added kefir and control
sweetened milk kefir as compared to control. However, kefir with kefir showed no significant (p>0.05) difference in colour and
8 and 10% sugar showed lower textural properties which may be appearance (Fig. 3 c). Whereas oat fibre added kefir showed
due to higher CO2 production in the kefir. Whey pockets and gas significantly (p<0.05) inferior colour and appearance when
holes were observed with increasing sugar content in kefir. Since compared to control but significantly (p<0.05) better than soya
kefir added with 6% sugar showed the best sensorial attributes, fibre added kefir (Fig. 3 c). Overall acceptability of inulin added

127
Indian J Dairy Sci 74(2): 124-130

Flavour Body and texture

10 10
c b
b b a
8 a a a
8
Score

6 6

Score
4 4
2
2
0
0
re

lin
re
l
tro

re

in
re
ib

ro
fib

ul
fib

fib
n

In
f

nt
Co

In
at
a

Co

at
ya
y

O
So

O
So
Colour and appearance Overall acceptability
10 10
c a b c b
a a a
8 8

6
Score

6
Score

4 4

2 2

0 0
re

li n
e

re
l

in
e
l
tro

ro
r

r
fi b

fi b
fib

ul
fib
u

nt
n

In

In
Co

at

Co

at
ya

ya
O

O
So

So

Fig. 3 Effect of dietary fibres incorporation on sensory attributes of sweetened milk kefir

Table 1 Effect of sugar addition on acidity and pH of milk kefir

Attributes Control 6% Sugar 8 % Sugar 10 % Sugar
Acidity 1.13 ± 0.01b 1.07 ± 0.05b 0.98 ± 0.02a 0.99 ± 0.01a
pH 4.43 ± 0.01a 4.44 ± 0.01a 4.49 ± 0.03b 4.48 ± 0.02b

Mean ± S.D; means with different superscripts in a row differ significantly (p<0.05) (n=3)

kefir was maximum followed by control and then kefir added with soluble as compared to oat fibre, but sensory attributes were
oat and soya fibre, respectively (Fig. 3 d). The better sensory least in kefir added with soya fibre. The lower sensory attributes
attributes of inulin added kefir might be because of additional of kefir with oat fibre were due to settling of fibres at the bottom
sweetening effect of inulin which might have masked the acidic of container during incubation which resulted in an unacceptable
taste of kefir and improved the flavour (Allgeyer et al. 2010). No appearance.
significant (p>0.05) difference was found in terms of taste and
consistency when inulin was added to kefir made with skim milk Effect of dietary fibres incorporation on pH and acidity of
powder (Glibowski and Kowalska 2012). Similarly, Ertekin and sweetened milk kefir
Guzel- Seydim (2010) found that odour and taste of kefir samples
Soya fibre added kefir showed significantly (p<0.05) higher acidity
were indifferent with or without inulin. Loss of flavour, colour
as compared to other samples. No significant (p>0.05) difference
and appearance in soya milk kefir fortified with soya fibre was
was observed in pH among all types of kefir (Table 2). Typically,
also reported by Baú, et al. (2014). Although soya fibre is relatively

128
 Indian J Dairy Sci 74(2): 124-130

Firmness (N) C onsistency (N .s)

d 8
0 .8
c
b bc 6 bc
0 .6 b

4 a
0 .4 a
2
0 .2
0
0 .0

re

lin
re
l
o
tr

b
lin

u
re
l

re
ro

fi
fi
n

In
fib
f ib

t
t

a
on

In

O
So
at
a
C

oy

O
S

Index of viscosity (N.s) Stickiness (N)

0.8 0.8 c
b
0.6 c 0.6 c
b
b
0.4 0.4
a
0.2 0.2 a

0.0 0.0

in
re
l

re
in
re
l

re

ro
ro

ul
ib
fib
ul
fib
fib

nt
nt

In
tf
In

Co

ya
Co

Oa
t
ya

Oa

So
So

Fig. 4 Effect of dietary fibres incorporation on textural properties of sweetened milk kefir
Table 2 Effect of dietary fibres incorporation on acidity and pH of sweetened milk kefir

Attributes Control kefir (6%S) Soya fibre Oat fibre Inulin

Acidity 1.07 ± 0.12a 1.21 ± 0.03c 1.12 ± 0.06ab 1.09 ± 0.03ab
pH 4.45 ± 0.04a 4.34 ± 0.12a 4.42 ± 0.04a 4.44 ± 0.02a

Mean ± S.D; means with different superscripts in a row differ significantly (p<0.05) (n=3)
pH of kefirs made in dairy industry ranged between pH 4.3 and with inulin showed optimum pH and acidity and obtained better
4.4, and similar pH values were observed in the present study, sensorial and textural properties.
where addition of different fibers did not affect pH and acidity
significantly (p>0.05) except that higher acidity in soya fiber Effect of dietary fibre incorporation on textural properties of
added kefir was observed. Baú et al. (2014) in the study with sweetened milk kefir
soya milk kefir prepared with soya fibre (3% w/w) showed higher
acidity and lower pH as compared to kefir without soya fibre and Firmness was significantly (p<0.05) increased after addition of
they concluded that some fibre may stimulate the metabolism of inulin in the preparation of kefir (Fig. 4 a). It was highest for
the kefir grains resulting in higher acidity. Ertekin and Guzel- inulin added kefir, followed by oat and soya fibre added kefir and
Seydim (2010) studied the effect of 2% inulin on physicochemical then control kefir (Fig. 4 a). Consistency was significantly (p<0.05)
properties of kefir and pH was found to be between 4.29 and 4.40. better in inulin added kefir (Fig. 4 b). Kefir added with soya and
They concluded that neither high performance nor native inulin oat fibre also showed significantly (p<0.05) higher consistency
did affect the pH changes in kefirs significantly (p>0.05). Although than control kefir (Fig. 4 b). It was witnessed that index of viscosity
in the present study, there were no significant (p>0.05) differences of inulin added kefir was maximum among the four samples (Fig.
in pH and acidity of different fibre added kefirs, but kefir added 4 c). Similarly, stickiness of kefir was enhanced after inulin

129
Indian J Dairy Sci 74(2): 124-130

addition as compared to control kefir (Fig. 4 d). Soluble fibers like Crouse JR, Morgan T, Terry JG, Ellis J, Vitolins M, Burke GL (1999) A
inulin formed viscous gel and modified the product textural Randomized trial comparing the effect of casein with that of soy
protein containing varying amounts of isoflavones on plasma
properties. Sendra et al. (2010) have also reported increased
concentrations of lipids and lipoproteins. Arch Intern Med 159(17):
firmness and viscosity in fermented milk products with the 2070-2076.
addition of different fibres. In the present study inulin added De Moreno de LeBlanc A, Matar C, Farnworth E, Perdigón G (2007) Study
kefir showed significantly (p<0.05) higher textural properties as of immune cells involved in the antitumor effect of kefir in a murine
compared to control, oat and soya fibre added kefir which may breast cancer model. J Dairy Sci 90: 1920–1928
be ascribed to stable gel formation being soluble fibre as Dongowski G, Drzikova B, Senge B, Blochwitz R, Gebhardt E, Habel A
(2005) Rheological behaviour of β-glucan preparations from oat
compared to relatively less soluble oat and soya fibre which products. Food Chem 93: 279–291
subsequently settled in the bottom. Moreover, the increased Elleuch M, Bedigian D, Roiseux O, Besbes S, Blecker C, Attia H
viscosity in inulin added kefir may be attributed due to increased (2011) Dietary fibre and fibre-rich by-products of food processing:
total solids content and due to the higher molecular weight of Characterisation, technological functionality and commercial
inulin (Buriti et al. 2010). Increased production of polysaccharide applications: A review. Food Chem 124: 411–421
due to the prebiotic effect of inulin must have also indirectly Ertekin B, Guzel-Seydim ZB (2010) Effect of fat replacers on kefir quality.
J Sci Food Agric 90: 543-548
decreased the syneresis, increased the viscosity and firmness Farnworth ER (2003). In: Handbook of fermented functional foods. CRC,
during the product storage (Jolly et al. 2002). Boca Raton, FL.
Ghosh J, Rajorhia GS (1990) Technology for production of mistidahi – A
Conclusions traditional fermented milk product. Indian J Dairy Sci 43: 239-246
Glibowski P, Kowalska A (2012) Rheological, texture and sensory
An attempt was made to develop fibre fortified sweetened milk properties of kefir with high performance and native inulin. J Food
kefir as a potential healthy alternative to mistidohi and yogurt. Eng 111: 299–304
Hecker KD, Meier ML, Newman RK, Newman CW (1998) Barley β-
Sensory evaluation of developed sweetened milk kefir revealed glucan is effective as a hypocholesterolaemic ingredient in foods. J
that addition of 6% sugar made its taste more palatable which Sci Food Agric 77: 179–183
was liked by the taste of the Indian populace. Inulin addition of Jolly L, Vincent SJF, Duboc P, Neeser J-R (2002) Exploiting
3% improved the textural properties of sweetened kefir and exopolysaccharides from lactic acid bacteria. In: Lactic Acid Bacteria:
contributed to its acceptance. An acceptable quality fortified Genetics, Metabolism and Applications. 367–374
Mann JI, Cummings JH (2009) Possible implications for health of the
sweetened milk kefir can be prepared with 0.1% pectin, 6% sugar
different definitions of dietary fibre. Nutr Metab Cardiovasc Dis 19:
and 3% Inulin fortification. 226–229
Messina E, De Angelis L, Frati G, Morrone S, Chimenti S, Fiordaliso F,
Acknowledgments Vivarelli E (2004) Isolation and expansion of adult cardiac stem
cells from human and murine heart. Circ Res 95: 911-921
The first author acknowledges the receipt of fellowship from the Roberfroid MB (2005) Introducing inulin-type fructans. Br J Nutr 93: 13-
institute of ICAR-National Dairy Research Institute (SRS) to carry 25.
out the research. Satir G, Guzel-Seydim ZB (2016) How kefir fermentation can affect product
composition? Small Ruminant Res 134: 1-7
Sendra E, Kuri V, Fernández-López J, Sayas-Barberá E, Navarro C, Pérez-
References Alvarez JA (2010) Viscoelastic properties of orange fiber enriched
yogurt as a function of fiber dose, size and thermal treatment. LWT
Akter N, Nahar A, Islam M, Al-Amin M (2010) Effects of different level - Food Sci Technol 43: 708-714
of starter culture and sugar on manufacturing characteristics of Spillane WJ (2006) Optimising sweet taste in foods, CRC Press, Boca
MistiDahi (Sweet Yoghurt). J Bangladesh Agril Univ 8: 7933 Raton, FL, p. 415
Allgeyer LC, Miller MJ, Lee S-Y (2010) Drivers of Liking for Yogurt Tamai Y, Yoshimitsu N, Watanabe Y, Kuwabara Y, Nagai S (1996) Effects
Drinks with Prebiotics and Probiotics. J Food Sci 75(4): S212– of milk fermented by culturing with various lactic acid bacteria and
S219. a yeast on serum cholesterol level in rats. J Ferment Bioeng 81:
Angulo L, Lopez E, Lema C (1993) Microflora present in kefir grains of 181–182
the Galician region (North-West of Spain). J Dairy Res 60: 263 Van Wyk J, Witthuhn RC, Britz TJ (2011) Optimisation of vitamin B12
AOAC, (2012). Official methods of analysis of AOAC international, 19 th and folate production by Propionibacterium freudenreichii strains
edition, Washington DC in kefir. Int Dairy J 21: 69–74
Baú TR, Garcia S, Ida EI (2014) Evaluation of a functional soy product Wood P, Braaten JT, Scott FW, Riedel KD, Wolynetz MS, Collins MW
with addition of soy fiber and fermented with probiotic kefir culture. (1994) Effect of dose and modification of viscous properties of oat
Braz Arch Biol Technol 57: 402–409 gum on plasma glucose and insulin following an oral glucose load. Br
Bosscher D, Van Caillie-Bertrand M, Van Cauwenbergh R, Deelstra H J Nutr 72: 731-35
(2003) Availabilities of calcium, iron, and zinc from dairy infant
formulas is affected by soluble dietary fibers and modified starch
fractions. Nutr 19: 641–645
Buriti FCA, Castro IA, Saad SMI (2010) Effects of refrigeration, freezing
and replacement of milk fat by inulin and whey protein concentrate
on texture profile and sensory acceptance of synbiotic guava mousses.
Food Chem 123: 1190–1197

130