568
Alexandra Galetovi´ c C. and L. Dufossé
22.5 Preservative Substances and Microencapsulation
of Phycobiliproteins
Natural pigments such as phycobiliproteins have the disadvantage of being more
sensitive to temperature, pH, humidity, and light compared to chemical dyes. Due
to the above, the use of preservatives such as citric acid, sodium chloride, calcium
chloride, benzoic acid, sugars among others, and microencapsulation have been used
to increase stability against these abiotic factors and can be used in food.
In C-phycocyanin from Arthrospira platensis, citric acid was used as an edible
preservative at 80 °C, for one hour and an increase in the stability of this pigment was
observed (Pan-utai et al. 2018). The work of Mishra et al. (2008) in the cyanobacterium Spirulina platensis, also shows that citric acid (4 mg/mL) was the best preservative for PC at 35 °C, in aqueous solution for 15 days, without loss of stability when
compared to C-PC at 0 °C. It is also recommended to use preservatives substances
before lyophilizing the purified C-PC with food grade and using amber or darkcolored bottles, to avoid the degradation and loss of color due to effects of light,
temperature, and oxygen.
In the phycoerythrin of Pseudanabaena sp. sodium chloride, sucrose, calcium
chloride, and citric acid (4 mg/mL) were used. The citric acid was the best preservative
between 0 and 35 °C at pH 7 for 45 days. The amount of phycoerythrin remaining
was 46 and 38% at 35 °C (Mishra et al. 2010).
Additionally, the PE and PC of the cyanobacterium Nostoc sp. HKAR-2 strain
improved stability in the presence of edibles preservatives, benzoic acid, citric acid,
sucrose, ascorbic acid, and calcium chloride over 30 days of incubation at 4, 25, and
40 °C. The best preservative was benzoic acid, the average lifetime was 100 and 86
days at 25 and 40 °C, respectively, at pH 7 (Kannaujiya and Sinha 2016).
In the case of the PC Spirulina platensis is stable at pH 5–6, low temperature, dark,
and with the addition of edible stabilizers. Sucrose, glucose, and sodium chloride
were added to PC solutions at pH 5–8 at a concentration of 20% (w/v) of each of the
compounds and were incubated at 65 °C for 30 min, the best condition was at pH 5
with NaCl (Wu et al. 2016).
Recently was reported, that the halophilic Euhalothece sp. which tolerates temperatures up to 45 °C and is highly stable at pH 5–8. After 2 h of incubation at 45 °C, 80%
of C-PC remained in solution. The addition of sodium azide and citrate preservatives
at 4 °C improves preservation for up to 42 weeks (Mogany et al. 2018).
The phycocyanin of Spirulina platensis was stabilized using different sugars, such
as methylglyoxal (MGO), which modifies the microenvironment of the chromophore
by interacting with apoprotein. The stability of phycocyanin improved by doing
crosslinking with MGO, present in high concentrations in honey Manuka honey, but
when testing with conventional honey (with lower MGO content), no differences
in stability were observed, suggesting that sugars (mono and disaccharides) present
in honey, are responsible for the stability of phycocyanin. The presence of 62%
fructose has the same effect as honey in the stabilization of phycocyanin. The stability
Alexandra Galetovi´ c C. and L. Dufossé
22.5 Preservative Substances and Microencapsulation
of Phycobiliproteins
Natural pigments such as phycobiliproteins have the disadvantage of being more
sensitive to temperature, pH, humidity, and light compared to chemical dyes. Due
to the above, the use of preservatives such as citric acid, sodium chloride, calcium
chloride, benzoic acid, sugars among others, and microencapsulation have been used
to increase stability against these abiotic factors and can be used in food.
In C-phycocyanin from Arthrospira platensis, citric acid was used as an edible
preservative at 80 °C, for one hour and an increase in the stability of this pigment was
observed (Pan-utai et al. 2018). The work of Mishra et al. (2008) in the cyanobacterium Spirulina platensis, also shows that citric acid (4 mg/mL) was the best preservative for PC at 35 °C, in aqueous solution for 15 days, without loss of stability when
compared to C-PC at 0 °C. It is also recommended to use preservatives substances
before lyophilizing the purified C-PC with food grade and using amber or darkcolored bottles, to avoid the degradation and loss of color due to effects of light,
temperature, and oxygen.
In the phycoerythrin of Pseudanabaena sp. sodium chloride, sucrose, calcium
chloride, and citric acid (4 mg/mL) were used. The citric acid was the best preservative
between 0 and 35 °C at pH 7 for 45 days. The amount of phycoerythrin remaining
was 46 and 38% at 35 °C (Mishra et al. 2010).
Additionally, the PE and PC of the cyanobacterium Nostoc sp. HKAR-2 strain
improved stability in the presence of edibles preservatives, benzoic acid, citric acid,
sucrose, ascorbic acid, and calcium chloride over 30 days of incubation at 4, 25, and
40 °C. The best preservative was benzoic acid, the average lifetime was 100 and 86
days at 25 and 40 °C, respectively, at pH 7 (Kannaujiya and Sinha 2016).
In the case of the PC Spirulina platensis is stable at pH 5–6, low temperature, dark,
and with the addition of edible stabilizers. Sucrose, glucose, and sodium chloride
were added to PC solutions at pH 5–8 at a concentration of 20% (w/v) of each of the
compounds and were incubated at 65 °C for 30 min, the best condition was at pH 5
with NaCl (Wu et al. 2016).
Recently was reported, that the halophilic Euhalothece sp. which tolerates temperatures up to 45 °C and is highly stable at pH 5–8. After 2 h of incubation at 45 °C, 80%
of C-PC remained in solution. The addition of sodium azide and citrate preservatives
at 4 °C improves preservation for up to 42 weeks (Mogany et al. 2018).
The phycocyanin of Spirulina platensis was stabilized using different sugars, such
as methylglyoxal (MGO), which modifies the microenvironment of the chromophore
by interacting with apoprotein. The stability of phycocyanin improved by doing
crosslinking with MGO, present in high concentrations in honey Manuka honey, but
when testing with conventional honey (with lower MGO content), no differences
in stability were observed, suggesting that sugars (mono and disaccharides) present
in honey, are responsible for the stability of phycocyanin. The presence of 62%
fructose has the same effect as honey in the stabilization of phycocyanin. The stability