Contents lists available at ScienceDirect
Algal Research
journal homepage: www.elsevier.com/locate/algal
Microalgae biomass as an alternative ingredient in cookies: Sensory,
physical and chemical properties, antioxidant activity and in vitro
digestibility
Ana Paula Batista
a,⁎
, Alberto Niccolai
b
, Patrícia Fradinho
a
, Solange Fragoso
a
, Ivana Bursic
a
,
Liliana Rodolfi
b,c
, Natascia Biondi
b
, Mario R. Tredici
b
, Isabel Sousa
a
, Anabela Raymundo
a
a
LEAF – Linking Landscape, Environment, Agriculture and Food, Instituto Superior de Agronomia, Universidade de Lisboa, Tapada da Ajuda, 1349-017 Lisboa, Portugal
b
Department of Agrifood Production and Environmental Sciences (DISPAA), University of Florence, Piazzale delle Cascine 24, 50144 Florence, Italy
c
Fotosintetica & Microbiologica S.r.l., Via dei Della Robbia 54, 50132 Florence, Italy
ARTICLE INFO
Keywords:
Microalgae
Novel foods
Digestibility
Antioxidants
Phenolics
ABSTRACT
Microalgae can be regarded as an alternative and promising food ingredient due to their nutritional composition,
richness in bioactive compounds, and because they are considered a sustainable protein source for the future.
The aim of this work was to evaluate microalgae (Arthrospira platensis F & M-C256, Chlorella vulgaris Allma,
Tetraselmis suecica F & M-M33 and Phaeodactylum tricornutum F & M-M40) as innovative ingredients to enhance
functional properties of cookies. Two biomass levels were tested and compared to control: 2% (w/w) and 6% (w/
w), to provide high levels of algae-bioactives. The cookies sensory and physical properties were evaluated during
eight weeks showing high color and texture stability. Cookies prepared with A. platensis and C. vulgaris presented
significantly (p < 0.05) higher protein content compared to the control, and by sensory analysis A. platensis
cookies were preferred. Besides, A. platensis also provided a structuring effect in terms of cookies texture. All
microalgae-based cookies showed significantly higher (p < 0.05) total phenolic content and in vitro antioxidant
capacity compared to the control. No signifi cant difference (p < 0.05) in in vitro digestibility between micro-
algae cookies and the control was found.
1. Introduction
Microalgae can be considered an innovative and promising food
ingredient, rich in nutrients such as high value proteins, long-chain
polyunsaturated fatty acids, carotenoids, vitamins, minerals, and phe-
nolics as well as other bioactive molecules [1].Different companies are
currently investing in this innovative microalgae-based food sector,
such as Terravia (ex-Solazyme, USA), currently producing and com-
mercializing algae food ingredients such as protein isolates and culinary
oils (http://terravia.com/). Another example is Dulcesol Group (http://
en.dulcesol.com/), leader in baked products and pastries sector in
Spain, which has also invested in a microalgae production unit for
developing a healthy baked product line with Chlorella incorporation
[2–3]. Moreover, other companies are starting to pay attention to this
area and according to Credence Research Report [4] the international
algae products market is expected to reach US$ 44.7 billion by 2023,
growing at a compound annual growth rate of > 5.0% in the
2016–2023 period. Nutraceuticals dominate the algae products market
followed by Food & Feed applications [4].
However, Europe lacks a gastronomy tradition and consumer his-
tory with microalgae (in contrast with some South-East Asia countries),
which makes effective marketing and consumer acceptability of mi-
croalgae based products more difficult [5]. In fact, the use of micro-
algae as a food source is still poorly developed in Europe, which has
been mainly attributed to three major factors: i) technical difficulties
related to their cultivation and high production costs; ii) low demand in
European countries compared to Asian markets; iii) strict European
legislation regarding Novel Foods [5].
In the last years some works have been published on innovative and
healthy food products integrated with microalgal biomass such as pasta,
biscuits and vegetarian “mayonnaises” and gelled desserts [6–12]. Al-
though the bioactive properties of microalgae biomass and/or of its
extracts has been extensively demonstrated (e.g. [1,13]), only few stu-
dies deal with bioactivity of microalgae-based foods and their response
to different processing steps [10,14]. There is a lack of knowledge on
how food processing conditions infl uence digestibility, bioavailability
and bioactive properties of microalgae functional ingredients in dif-
ferent food matrixes.
http://dx.doi.org/10.1016/j.algal.2017.07.017
Received 24 March 2017; Received in revised form 6 June 2017; Accepted 15 July 2017
⁎
Corresponding author.
E-mail address: paulabatista@isa.ulisboa.pt (A.P. Batista).
Algal Research 26 (2017) 161–171
2211-9264/ © 2017 Elsevier B.V. All rights reserved.
MARK
Cookies are considered a convenient nutritious dense snack food,
widely consumed by European citizens from all age groups. There is a
tendency for research and innovation in this market segment, which
promotes the inclusion in cookies of healthy ingredients, such as anti-
oxidants, vitamins, minerals, proteins and fibers [15–16]. The inclusion
of microalgae biomass in cookies has been previously reported for
coloring purposes with Chlorella vulgaris [7], omega-3 fatty acids sup-
plementation with Isochrysis galbana [8], and antioxidant activity with
Spirulina [11 –12].
The aim of this work was to study microalgae addition to enhance
functional properties of this baked food matrix, especially at high bio-
mass incorporation levels. It was intended to use significantly higher
concentrations than the ones found in commercial algal products (ty-
pically below 1% w/w), in order to provide higher levels of bioactive
compounds, while not compromising sensorial acceptability and di-
gestibility. Four microalgae strains were tested - Arthrospira platensis
F & M-C256, Chlorella vulgaris Allma, Tetraselmis suecica F & M-M33, and
Phaeodactylum tricornutum F & M-M40.
A. platensis (commonly known as “spirulina”), consumed by human
populations since ancient times [17] and C. vulgaris, C. luteoviridis and
C. pyrenoidosa have been consumed in the EU for several decades and
are thus authorized as food in the European Union [18–19]. A. platensis
has been widely consumed as nutritional supplement due to its asso-
ciated health benefits, such as high protein (up to 60%), vitamin B12, γ-
linolenic acid (GLA) and phycocyanin content [20]. Chlorella is also rich
in protein, as well as pigments and glucans which can act as im-
munostimulants [21–22].
Tetraselmis chuii has recently been authorized for commercialization
as novel food ingredient through an application by the company
Fitoplancton Marino S.L. (Cadiz, Spain) [23]. In the present study,
another species belonging to the same genus, T. suecica, was used. This
marine chlorophyte is characterized by high content in polyunsaturated
fatty acids and α-tocopherol [24].
P. tricornutum is a marine diatom which has not yet been submitted
to novel food application. Nevertheless, it was included in the present
study considering its high content in eicosapentaenoic acid (EPA 20:5
ω3) as well as in fucoxanthin, a carotenoid associated with antioxidant,
anti-diabetes and anti-obesity effects [25–26]. Moreover, previous in
vitro toxicity tests by Niccolai et al. [27] showed no adverse effects of
methanolic and aqueous extracts of these biomasses on Artemia salina.
2. Materials and methods
2.1. Microalgae strains and biomass production
Arthrospira platensis F & M-C256 and Tetraselmis suecica F & M-M33
biomasses were provided by Archimede Ricerche S.r.l. (Camporosso,
Imperia, Italy) and Phaeodactylum tricornutum F & M-M40 was produced
at the facility of Fotosintetica & Microbiologica S.r.l. (Sesto Fiorentino,
Florence, Italy). A. platensis F & M-C256, T. suecica F & M-M33, and P.
tricornutum F & M-M40 were cultivated in GWP®-I [28] or GWP®-II
photobioreactors [29–30] in semi-batch mode, then the biomasses were
harvested by centrifugation, frozen, lyophilized, powdered and stored
at − 20 °C until analysis. A. platensis F & M-C256 biomass was washed
with tap water to remove excess bicarbonate before being frozen.
Chlorella vulgaris Allma biomass was obtained from Allma Microalgae
(Lisbon, Portugal). The two marine strains (T. suecica F & M-M33 and P.
tricornutum F & M-M40) were cultivated in F medium [31], while A.
platensis F & M-C256 was cultivated in Zarrouk medium [32]. The bio-
chemical composition of the di fferent biomasses, determined as re-
ported in Abiusi et al. [33], is presented in Table 1.
2.2. Cookies preparation
Cookies were prepared according to a previously optimized for-
mulation [7–8], using wheat flour, sugar, baking powder, margarine,
and microalgae biomass, as indicated in Table 2. A control, without
microalgae incorporation was also prepared and further analyzed.
Batches of 150 g were prepared, yielding around 10 cookies per batch.
The ingredients were mixed in a food processor (Bimby, Vorwerk),
kneading 15 s at speed 4. The cookies were then molded into 46.5 mm
diameter and 5 mm height circles disks and baked at 110 °C for 40 min.
After cooling, sample cookies were stored at room temperature in
hermetic containers, protected from light. Physical analyses (color,
texture, and a
w
) were performed after 24 h, and after 8 weeks storage.
Some of the cookies batches were immediately crushed to powder
(using an electric mill) and frozen to be used for chemical composition,
antioxidant capacity and in vitro digestibility analyses.
2.3. Cookies analyses
2.3.1. Color analysis
The color of cookies samples was measured instrumentally using a
Minolta CR-400 (Japan) colorimeter with standard illuminant D65 and
a visual angle of 2°. The results were expressed in terms of L*, lightness
(values increase from 0 to 100%); a*, redness to greenness (60 to −60
positive to negative values, respectively); b*, yellowness to blueness (60
to −60 positive to negative values, respectively), according to the
CIELab system. Chroma, C*
ab
(saturation), and hue angle, h°
ab
, were
also calculated, as defined by: C*
ab
= [(a*
2
+b*
2
)]
1/2
;h°
ab
= arctan
(b* / a*). The total color difference between sample cookies along
storage time (up to eight weeks), as well as between raw and cooked
samples, was determined using average L*a*b* values according to:
ΔE* = [(ΔL*)
2
+(Δa*)
2
+(Δb*)
2
]
1/2
. The measurements were con-
ducted under the same light conditions, using a white standard
(L* = 94.61, a* = − 0.53, b* = 3.62), under artificial fluorescent light
at room temperature, replicated ten times for each formulation sample
(one measurement per cookie), as well as for the control, 24 h and
8 weeks after preparation.
2.3.2. Texture analysis
The cookie texture was measured using a texturometer TA.XTplus
(Stable MicroSystems, UK) in penetration mode with a cylindrical
aluminum probe of 2 mm diameter plunged 3 mm at 1 mm s
− 1
. The
resistance to penetration, or hardness, was measured by the total area
below the force vs. time curve, corresponding to the penetration work
Table 1
Biochemical composition of the four microalgae biomasses used in the experiments (%,
dry weight). Results are expressed as average ± standard deviation (n = 3).
Protein (%) Carbohydrate (%) Lipid (%) Ash (%)
A. platensis F&M-
C256
68.9 ± 1.0 12.8 ± 0.2 10.7 ± 0.6 6.1 ± 0.1
C. vulgaris Allma 56.8 ± 2.7 5.9 ± 0.3 16.9 ± 2.8 9.3 ± 1.5
T. suecica F&M-
M33
40.2 ± 0.5 10.2 ± 0.2 28.5 ± 1.2 15.7 ± 0.2
P. tricornutum
F & M-M40
38.8 ± 0.1 11.0 ± 0.7 19.3 ± 1.7 14.8 ± 0.1
Table 2
Cookie formulations (%, w/w). F1 - control cookie formulation; F2 - 2% algae cookie
formulation; F3 - 6% algae cookie formulation.
Ingredients F1 (control) F2 F3
g/100 g g/100 g g/100 g
Wheat flour 49 47 43
Sugar 20 20 20
Margarine 20 20 20
Water 10 10 10
Baking powder 1 1 1
Microalgae 0 2 6
A.P. Batista et al.
Algal Research 26 (2017) 161–171
162
(N.s). Measurements were repeated ten times for each formulation
sample (one measurement per cookie), as well as for the control, 24 h
and 8 weeks after preparation.
2.3.3. Water activity (a
w
) determination
The cookie water activity (a
w
) was determined using an HygroPalm
HP23-AW (Rotronic AG, Switzerland), at 20 ± 1 °C. Measurements
were repeated four times for each sample (crushed powder), as well as
for the control, 24 h and 8 weeks after preparation.
2.3.4. Proximate chemical composition determination
Cookie moisture content was determined gravimetrically using an
automatic moisture analyzer PMB 202 (aeADAM, Milton Keynes, UK) at
130 °C, until constant weight.
Total ash content was determined gravimetrically by incineration at
550 °C in a muffle furnace.
Crude protein was determined by the Kjeldhal method according to
the AOAC 950.36 official method for baked products [34]. The de-
termined total nitrogen content was multiplied by a conversion factor of
5.7 to obtain the cookie crude protein content.
The cookie crude fat content was determined according to the
procedure used for cereals and derived products in the Portuguese
standard method NP4168 [35]. This procedure is based on the hydro-
lysis of the bonds between lipids, proteins, and carbohydrates by using
hydrochloric acid, ethanol and formic acid, followed by filtration and
extraction with n -hexane in a Soxhlet extractor for 6 h. The crude fat
residue was determined gravimetrically, after solvent evaporation in a
rotary evaporator and oven drying.
All chemical composition analyses were repeated, at least in tripli-
cate, and were performed after cookie preparation.
2.3.5. Phycocyanin, phenolics and antioxidant capacity determination
Phycocyanin content was determined in A. platensis cookie, and
respective dough samples, according to the method developed by
Boussiba & Richmond [36] modified by Reis et al. [37]. This method is
based on the extraction of these water soluble pigments with phosphate
buffer at pH 7, 0.1 M at low temperatures and spectrophotometric
quantification at 620 nm (C-phycocyanin) and 650 nm (C-allophyco-
cyanin).
For total phenolic content determination, extracts were prepared
according to the procedure used by Hajimahmoodi et al. [38]. The total
phenolic content in the extracts was determined according to Rajauria
et al. [39], using the Folin Ciocalteu assay. Results were expressed in
gallic acid equivalents (mg GAE g
− 1
) of dry microalgae biomass and
cookies, through a calibration curve with gallic acid (0 to
500 μgmL
− 1
).
The antioxidant capacity of the cookies and microalgae samples was
assessed by direct quencher procedure, as optimized by Serpen et al.
[40–41] for cereal products, using Ferric Reducing Antioxidant Power
(FRAP) as quantification method. Two blank assays, one without
sample and another without reagents were also performed. Standard
calibration curves were made using Trolox standard solutions that were
submitted to the same FRAP protocol. The antioxidant capacity of the
samples was expressed in terms of mmol of Trolox Equivalent Anti-
oxidant Capacity (TEAC) per kilogram of sample. Analyses were re-
peated in triplicate and performed after cookie preparation.
2.3.6. In vitro digestibility tests
The cookies and microalgae biomasses in vitro digestibility (IVD)
was assessed by the Boisen & Fernández method [42]. Microalgae bio-
mass and cookie samples were weighed (1 g, particle size ≤ 1 mm) and
transferred in 250 mL conical flasks. To each flask, phosphate buffer
(25 mL, 0.1 M, pH 6.0) was added and mixed, followed by HCl (10 mL,
0.2 M) and pH was adjusted to 2.0. A freshly prepared pepsin water
solution (3 mL; Applichem, Darmstadt, Germany) containing 30 mg of
porcine pepsin (0.8 FIP-U/mg) was added. The flasks were incubated at
39 °C for 6 h with constant agitation (150 rpm). After, phosphate buffer
(10 mL, 0.2 M, pH 6.8) and NaOH solution (5 mL, 0.6 M) were added to
each sample and pH was adjusted to 6.8. A freshly prepared pancreatin
ethanol:water solution (10 mL, 50:50 v/v) containing 500 mg of por-
cine pancreatin (42362 FIP-U/g, Applichem, Darmstadt, Germany) was
added to each sample. The flasks were incubated again at 39 °C,
150 rpm, for 18 h. A reagent blank without sample was also prepared.
The undigested residues were collected by centrifugation at 18,000 × g
for 30 min and washed with deionised water. This procedure was re-
peated twice and the final supernatant was filtered on glass-fiber
membranes (47 mm Ø, pore 1.2 μm). The pellet and membranes were
dried at 80 °C for 6 h, and then at 45 °C until constant weight.
The IVD (%) was calculated from the difference between the initial
biomass and the undigested biomass (after correction for the blank
assay) divided by the initial biomass and multiplied by 100. Analyses
were repeated in triplicate.
2.3.7. Sensory analysis
Sensory analysis assays were performed for cookies with C. vulgaris
and A. platensis (2% and 6%). An untrained panel of 41 people, 9 males
and 32 females, with ages between 18 and 60, evaluated the cookies in
terms of color, smell, taste, texture, global appreciation (6 levels from
“very pleasant” to “very unpleasant”). The buying intention was also
assessed, from “would certainly buy” to “ certainly wouldn't buy” (5 levels).
The assays were conducted in a standardized sensory analysis room,
according to the standard EN ISO 8589 [43].
2.4. Statistical analysis
Statistical
analysis of the experimental data was performed using
STATISTICA from StatSoft (version 8.0), through variance analysis (one
way ANOVA), by the Scheffé test – Post Hoc Comparison at a sig-
nificance level of 95% (p < 0.05). All results are presented as
average ± standard deviation.
3. Results and discussion
The cookies with microalgae biomass incorporation presented vi-
sually attractive and unusual appearances (Fig. 1). Innovative green
tonalities varied, depending on the microalga used, from a blueish-
green (A. platensis) to a brownish-green (P. tricornutum). The microalgae
cookies presented an average diameter of 46.8 ± 0.5 mm and an
average thickness of 7.5 ± 0.3 mm while the control cookie dimen-
sions were slightly higher (47.9 ± 1.5 mm diameter, 8.3 ± 0.5 mm
thickness).
3.1. Color stability
The results obtained for the cookie color parameters, lightness (L*),
greenness (a*), yellowness (b*), chroma (C*) and hue (h°) are presented
in Fig. 2. Regarding the lightness parameter L*, a reduction in lumin-
osity with increasing algae concentration can be observed.
An increase in microalgae concentration has also led to lower values
of the chromatic parameters a* and b* (in modulus), thus lower chroma
(C*), while the hue remains practically constant for each sample (100°
to 120°, between yellow and green, depending on the sample).
These results may seem unexpected, considering that in Fig. 1, the
cookies with 6% algae seem to have more intense green color. In pre-
vious studies, a similar effect was found for C. vulgaris [7] and Isochrysis
galbana [8] cookies, where a reduction in a* and b* parameters upon
increasing microalgae biomass concentration from 0.5% to 3.0% (w/w)
was observed. This effect may be related to a higher pigment de-
gradation with the baking process or with a pigment saturation effect,
above certain algae concentrations.
Cookies with 2% C. vulgaris and T. suecica presented the highest a*
values (in modulus) and intermediate b* values (22.8–25.3) (Fig. 2),
A.P. Batista et al.
Algal Research 26 (2017) 161–171
163
which is in agreement with the high chlorophyll content that char-
acterizes chlorophyte algae [1]. A. platensis cookies presented tonalities
similar to the chlorophyte cookies, although with less intensity (lower
a* and b* values, in modulus), reflecting the lower chlorophyll and
carotenoid content generally present in this alga [44]. On the other
hand, P. tricornutum cookies presented low a* values (in modulus) and
the highest b* values, resulting in a hue angle of 100°, closer to yellow
(90°) than to green (180°). These results should be related to the
Fig. 1. Control cookie and cookies with 2% (w/w) and 6% (w/w) microalgae biomass.
Fig. 2. Color parameters, L*, a*, b*, C* and h° of cookies with 2% and 6% (w/w) microalgae biomass incorporation, in week 0 (Ap – A. platensis,Cv– C. vulgaris,Ts– T. suecica,Pt– P.
tricornutum). Results are expressed as average ± standard deviation (n = 10).
A.P. Batista et al.
Algal Research 26 (2017) 161–171
164
presence of fucoxanthin, a carotenoid usually present in high con-
centrations in this marine diatom [25].
Table 3 presents the total color differences (ΔE*) between baked
and raw (dough) sample cookies. Microalgae cookies show significantly
color differences upon baking (ΔE* = 19–24). These differences result
mainly from a general increase in luminosity (probably associated to
water evaporation) and an accentuated hue angle tonality decrease in
the case of P. tricornutum (results not shown), which should be related
to pigment loss upon baking.
The color stability along conservation time can also be observed in
Table 3 through the calculation of total color difference of each sample
with time in relation to week 0. In all cases ΔE* is lower than 5 (except
for P. tricornutum 6% in week 8: 5.42) which means that the cookie
color differences are not detected by normal human vision [45].
Therefore, it can be concluded that the developed cookies present stable
colorations along eight weeks of storage.
3.2. Texture stability
The cookies texture was evaluated by penetration tests, and the
resulting hardness, expressed by resistance to penetration work, was
calculated from the texturograms and presented in Fig. 3.
At the beginning of the study (week 0), no significant differences
(p > 0.05) were found between the cookies with 2% algae when
compared to the control (and between different algae), which means
that adding 2% biomass does not prompt cookie structural changes that
can alter the resistance to probe penetration. Increasing microalgae
concentration from 2% to 6% causes significant (p < 0.05) hardness
increase, from 24 to 29 N.s (2% cookies) to 37–38 N.s for 6% C. vulgaris
and T. suecica cookies, to 50 N.s for P. tricornutum and to 63 N.s for A.
platensis cookies.
These results confirm the findings of previous water absorption tests
carried out with the same microalgae strains biomass [46], in which
significantly higher (p < 0.05) water absorption indexes (WAI:
4.4–5.0 g/g
alga
) and Oil Absorption Capacity (OAC: 1.8–2.2 g/g
alga
)
were obtained in relation to wheat flour (WAI: 2.1 g/g
flour
, OAC: 1.7 g/
g
flour
). The highest WAI and OAC values were attained for A. platensis,
followed by P. tricornutum, and at last, for C. vulgaris and T. suecica,
which can be related to the different nature of these algae cell walls
(peptidoglycan, silica and cellulose/hemicellulose, respectively). It is
possible that, when microalgae are added to the cookie dough, they
absorb more water and oil/fat, reinforcing the cookie internal structure.
These data suggest that it would be possible to increase the water
content or reduce the flour content, resulting in cookies with the same
texture properties than the control cookie.
These results are also in agreement with previous studies where it
was observed a linear increase in cookies hardness with C. vulgaris [7]
and I. galbana [8] at concentrations from 0.5% to 3.0%. Singh et al. [12]
also observed that increasing the content of A. platensis, from 1.6 to
8.4%, had positive effect on the hardness of sorghum flour biscuits. The
same “texturing” or “structuring” effect of microalgae has been described
also in other type of food products, such as fresh pastas with A. maxima
and C. vulgaris [9].
The evolution of cookies hardness with time can also be observed in
Fig. 3. The cookies did not present significant (p > 0.05) changes in
hardness after eight weeks of storage, except for A. platensis cookies.
3.3. Water activity
Water activity, a
w
, is an important physical parameter regarding
conservation of low moisture cookies, particularly for the maintenance
of a crispy texture [47].Ata
w
values below 0.5, no microbial pro-
liferation occurs. Lipid oxidation reactions, can be accelerated at high
a
w
by increased mobilization of reactant molecules, although it is also
recognized that very low water contents in fat-containing foods (e.g.
cookies with 3–5% moisture and 20% fat) are conductive to rapid
oxidation since substrates and reactants become more concentrated
[48].
Fig. 4 presents the results of a
w
for the microalgae cookies along
eight weeks. The control cookies presented an average a
w
value of 0.29
without significant differences with time (p < 0.05). Microalgae
cookies presented more variable behavior regarding a
w
values, with a
tendency for a
w
to increase along time. Overall, it should be noted that
for all samples, a
w
values were below 0.5, after eight weeks storage,
these a
w
variations did not promote any appreciable modification on
texture stability (Fig. 3).
Table 3
Total color variation (ΔE*) between cooked and raw cookie samples and color stability
along conservation time (ΔE* in relation to week 0).
Total color difference
(ΔE*)
Raw vs.
cooked
Week 1
vs.
week 0
Week 2
vs.
week 0
Week 3
vs.
week 0
Week 4
vs.
week 0
Week 8
vs.
week 0
Control 7.63 0.84 0.86 1.23 1.55 1.89
A. platensis 2% 16.01 0.60 0.66 1.16 1.63 1.86
6% 15.58 0.73 0.89 0.94 0.94 0.77
C. vulgaris 2% 11.22 0.70 1.17 0.96 0.74 1.12
6% 12.58 0.75 1.26 1.11 1.32 3.13
T. suecica 2% 15.93 1.02 1.73 2.43 2.49 2.78
6% 10.85 1.83 2.12 2.40 3.80 4.69
P. tricornutum 2% 18.97 1.50 2.03 2.48 2.37 4.19
6% 23.63 1.31 2.57 2.37 3.35 5.42
Fig. 3. Texture, expressed by penetration work (hardness, area N.s),
of cookies with 2% and 6% (w/w) microalgae biomass incorpora-
tion, along time (Ap – A. platensis,Cv– C. vulgaris,Ts– T. suecica,Pt–
P. tricornutum). Results are expressed as average ± standard de-
viation (n = 10). Samples marked with * showed significant
(p < 0.05) differences from week 0 to week 8.
A.P. Batista et al.
Algal Research 26 (2017) 161–171
165