Kinetic study on the effects of sugar addition on the thermal degradation of phycocyanin from Spirulina sp.
Introduction
Food colorants are widely used as an additive material in both manufacturing and consumer food industries due to their compatibility with food processes (Yamjala, Nainar, & Ramisetti, 2016). Natural food colorants from natural sources, such as plants or fruits, have been used since 1500 BCE, but they were replaced by synthetic colorants in the early 19th century because of the industrial revolution (Downham & Collins, 2000). Natural colorants currently dominate 31% of the dye market, whereas 40% are synthetic colorants (Mapari, Thrane, & Meyer, 2010). The rising market in natural colorants is caused by awareness of diet and health, which starts with the reduced consumption of synthetic material.
Several plants and fruits are currently used as natural colorants, such as Rosella (red), grape (purple), carrots (orange), blueberry (blue), or Pandanus leaves (green) (Duangmal, Saicheua, & Sueeprasan, 2008; Clydesdale, Francis, & Damon, 1978; Kirca, Ǒzkan & Cemeroğlu, 2007; Fracassetti et al., 2013; Ningrum, Minh, & Schreiner, 2015). However, the utilization of microalgae extract as a natural colorant is also increasing, particularly phycocyanin (blue) from Spirulina sp., β-carotene (orange) from Dunaliella sp., or astaxanthin (red) from Haematococcus sp. (Dufossé et al., 2005). Most food colorants are also used as antioxidants to reduce free radicals.
Phycocyanin is a natural colorant extracted from microalgae. This pigment–protein complex compound can be extracted from blue-green algae (cyanobacteria) Spirulina sp., and it is classified as a phycobiliprotein (Markou & Nerantzis, 2013). The molecular weight, position, and maximum absorption intensity of phycocyanin depend on the state of aggregation, which is affected by pH solution, temperature, protein concentration, and origin of the algae itself (Mishra, Shrivastav, & Mishra, 2008). Phycoyanin captures oxygen radicals because it contains an open tetraphyrrole chain that can bind a peroxy radical by donating hydrogen atoms, which are bonded in the 10th C atom from a tetraphyrrole molecule (Estrada et al., 2001, Romay et al., 2003).
In its application as a natural food colorant, degradation of color, concentration, and antioxidant activity often occurs due to high temperatures during food processing. Phycocyanin gradually changes from light blue to faint blue, and this transformation is a disadvantage in the food industry because of the resulting unattractive hue. Several techniques have been used to prevent the thermal degradation of phycocyanin, such as the addition of a stabilizer (Antelo et al., 2008, Sun et al., 2006), pH adjustment (Wu, Wang, Xiang, Li, & He, 2016), and encapsulation (Chen et al., 1996).
Stabilizer addition is commonly used to minimize the thermal degradation of phycocyanin due to its simplicity and economy. Sugar is a stabilizer that is typically used to stabilize proteins that are easily degraded, and it has a simple structure such as monosaccharide (glucose, fructose, and galactose) or disaccharide (maltose, lactose, and sucrose). Sugar can bind with protein via an N-linked glycosidic bond, which can minimize thermal degradation during food processing (Allison et al., 1999, Imamura et al., 2003). The utilization of sugar as a stabilizer in the food industry has been studied by Martelli, Folli, Visai, Daglia, and Ferrari (2014), who used sugar to reduce the anthocyanin degradation of raspberry. Meanwhile, Vikram, Ramesh, and Prapulla (2005) used sugar to reduce the nutrient degradation of orange juice. In another experiment, Sadilova, Stintzing, Kammerer, and Carle (2009) attempted to add sugar to fruit juices to stabilize the anthocyanin content. Therefore, sugar is a promising stabilizer that can be used to prevent the thermal degradation of phycocyanin.
In the present study, commercial sugar with simple structures (i.e., glucose, fructose, and sucrose) was used as a promising phycocyanin stabilizer to minimize thermal degradation. The reaction kinetics of the thermal degradation of phycocyanin and the activation energy were studied. Phycocyanin color changes were also observed before and after heating using a colorimeter. Enhanced antioxidant activity after heating will be helpful to establish a baseline protocol for antioxidant stability.
Section snippets
Materials and method
Phycocyanin extract from Spirulina platensis (in powder form) was purchased from CV Neoalgae (Sukoharjo, Indonesia). Glucose, sucrose, and fructose (industrial grade) were purchased from a local supermarket in Semarang in June 2016. 2,2-Diphenyl-1-picrylhydrazyl (DPPH), citric acid, and sodium citrate dihydrate were obtained from Sigma–Aldrich (St. Louis, MO, USA)
Sample preparation and heat processing
Phycocyanin samples were prepared for heating. Approximately 7.2 ml of 0.1 M citric acid and 42.8 ml of 0.1 M sodium citrate dihydrate
Effect of different kinds of sugar in heat processing on the phycocyanin concentration
The effect of different kinds of sugar added to phycocyanin subjected to heat treatment on the phycocyanin concentration must be determined. Fig. 1a shows the decrease in the phycocyanin concentration during heating at 40 °C. At this temperature, phycocyanin mixed with glucose could stabilize the concentration up to 95–97%, whereas phycocyanin mixed with sucrose, fructose, and without sugar demonstrated phycocyanin concentration stability of up to 70%, 71%, and 67%, respectively. At this
Conclusion
This study showed that the addition of sugar affected the stability, activation energy, color, and antioxidant activity of phycocyanin. The stability of phycocyanin was affected by the sugar–protein interaction via glycosidic bond, which could polymerize phycocyanin and prevent degradation reactions. In the thermal degradation kinetic model, the first-order kinetic model demonstrated an average R2 value of 0.967. The addition of glucose to phycocyanin could increase the activation energy by
Acknowledgement
This research was financially supported by Ministry of Research, Technology and Higher Education through Research grant PUSN 2017. Authors thanks to C-BIORE for their facilities and guidance.
References (33)
- et al.
Hydrogen bonding between sugar and protein is responsible for inhibition of dehydration-induced protein unfolding
Archieve of Biochemistry and Biophysics
(1999) - et al.
Thermal degradation kinetics of the phycocyanin from Spirulina platensis
Biochemical Engineering Journal
(2008) - et al.
Stability of phycocyanin extracted from Spirulina sp.: Influence of temperature, pH and preservatives
Process Biochem
(2012) - et al.
Colour evaluation of freeze-dried roselle extract as a natural food colorant in a model system of a drink
LWT-Food Science and Technology
(2008) - et al.
Microorganisms and microalgae as sources of pigments for food use: A scientific oddity or an industrial reality?
Trends in Food Science & Technology
(2005) - et al.
The stability of pelargonidin-based anthocyanin at varying water activity
Food Chemistry
(2001) - et al.
Carrot (Daucus carota L.) peroxidase inactivation, phenolic content and physical changes kinetics due to blanching
Journal of Food Engineering
(2010) - et al.
Effects of types of sugar on the stabilization of protein in the dried state
Journal of Pharmaceutical Science
(2003) - et al.
Degradation kinetic modelling of color, texture, polyphenols and antioxidant capacity of York cabbage after microwave processing
Food Research International
(2013) - et al.
Effects of temperature, solid content, and pH on the stability of black carrot anthocyanins
Food Chemistry
(2007)
Fungal polyketide azaphilone pigments as future natural food colorants?
Trends in Biotechnology
Microalgae for high-value compounds and biofuels production: A review with focus on cultivation under stress conditions
Biotechnology Advances
Thermal stability improvement of blue colorant C-Phycocyanin from Spirulina platensis for food industry applications
Process Biochemistry
A review of Maillard reaction in food and implications to kinetic modelling
Trends in Food Science and Technology
Effect of preservatives for food grade C-PC from Spirulina platensis
Process Biochemical
Matrix dependent impact of sugar and ascorbic acid addition on color and anthocyanin stability of black carrot, elderberry, and strawberry single strength and from concentrate juices upon thermal treatment
Food Research International
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