Astaxanthin from Phaffia rhodozyma: Microencapsulation with carboxymethyl cellulose sodium and microcrystalline cellulose and effects of microencapsulated astaxanthin on yogurt properties

Highlights

• A process for microencapsulation of astaxanthin by CMC-Na and MCC was developed.

• The stability of microencapsulated astaxanthin was significantly improved.

• A new functional yogurt with encapsulated astaxanthin was developed.

Abstract

In this study, the astaxanthin from Phaffia rhodozyma was encapsulated with carboxymethyl cellulose sodium (CMC-Na) and microcrystalline cellulose (MCC) by freeze-drying and used in yogurt. The encapsulation improved the stability, solubility, and antioxidation activity of the astaxanthin and increased the extent of its potential industrial application. The encapsulated efficiency and solubility of the microencapsulated astaxanthin were 58.76% and 52.88%, respectively. In comparison with non-encapsulated astaxanthin, the microencapsulation did prevent the astaxanthin from dramatic degradation, with an astaxanthin retention value of 80.86% in the microencapsulated astaxanthin at 55 °C in 16 h. Non-encapsulated astaxanthin was much more stable in acid than in neutral phase, but the microencapsulated astaxanthin showed no significant difference in stability under both conditions. The astaxanthin yogurt showed an attractive orange-red color as well as a significantly higher DPPH-scavenging activity and stability than the plain yogurt.

Introduction

Astaxanthin, one of the carotenoid pigments, is widely distributed in nature, especially in shrimp, crab, fish, algae, birds, yeast and Haematococcus pluvislis. Astaxanthin is well known for its health-promoting properties and stain ability. Its bioactivity is higher than that of any other known antioxidants and it could protect lipids of biological membranes from peroxidation (Preston et al., 2006). Inflammatory and oxidative mediated disorders including cancer, allergy, diabetes, neurodegenerative diseases and coronary heart diseases could be reduced by its polyunsaturated fatty acids (Anarjan, Tan, Nehdi, & Ling, 2012; Bustos-Garza, Yanez-Fernandez, & Barragan-Huerta, 2013). Astaxanthin could be favorable to animal and human health probably due to its ability to eliminate free radical and singlet oxygen (Gomez-Estaca, Comunian, Montero, Ferro-Furtado, & Favaro-Trindade, 2016). Furthermore, astaxanthin could also induce NF-E2-related factor 2 (Nrf2), which has been experimentally found to prevent cells from oxidative stress damage (Inoue et al., 2017). Oral astaxanthin prodrug CDX-085 could distribute among lipoproteins and lower total cholesterol and aortic arch atherosclerosis in low-density lipoprotein receptor negative mice (Ryu et al., 2012). Researchers demonstrated that feeding astaxanthin-supplemented diets could improve long snout seahorses’ egg quality and juvenile growth and survival (Palma, Andrade, & Bureau, 2017). Consequently, astaxanthin is widely used as a nutrition additive in various promising fields.

Despite its steadily increasing need in recent years, astaxanthin is still stifled by its strong odor, low aqueous solubility, rapid metabolism, highly conjugated structure and unsaturated nature. Native astaxanthin is red in color but it turns into blue or purple when complexed with proteins or lipoproteins (Higuera-Ciapara, Felix-Valenzuela, Goycoolea, & Arguelles-Monal, 2004). Free astaxanthin is susceptible to light, temperature, pH, and oxygen during thermal treatment or storage (Fathi, Mozafari, & Mohebbi, 2012; Gomez-Estaca, Balaguer, Gavara, & Hernandez-Munoz, 2012). Thus, it is necessary to overcome these limitations to improve astaxanthin properties for potential industrial applications.

There are many ways to solve the astaxanthin limitations such as microencapsulation with emulsions, liposomes, polymeric nanospheres, β-cyclodextrin complexes or calcium ions (Ambati, Phang, Ravi, & Aswathanarayana, 2014; Raposo, Morais, & Morais, 2012). Ai and Nyam (2016) fabricated a stable kenaf seed oil-in-water Pickering nanoemulsion by mixing sodium caseinate (SC), Tween 20 (T20) and β-Cylodextrin (β-CD) through a high pressure homogenizer. Tan, Xie, Zhang, Cai, and Xia (2016) developed the polysaccharide-based nanoparticles by the polyelectrolyte complex between chitosan (CS) and gum arabic (GA) as novel delivery systems for curcumin. Gomez-Estaca et al. (2016) used the novel biopolymer combination of gelatin and cashew gum to encapsulate an astaxanthin-containing lipid extract obtained from shrimp waste by complex coacervation. Microencapsulation of astaxanthin can be performed by emulsion/solvent evaporation, freeze-drying, solvent displacement and spray drying (Taksima, Limpawattana, & Klaypradit, 2015). The aforementioned studies suggest that the encapsulation technology to enable solid powders to contain the lipid extract might be a good way to tackle astaxanthin limitations. In this work CMC-Na and MCC are used as the wall materials of encapsulation on the study of the stability of astaxanthin from P. rhodozyma.

CMC-Na, one of the important water-soluble cellulose ether derivatives with negative charges, is synthesized by the alkali-catalyzed reaction of cellulose with chloroacetic acid (Miao, Chen, Li, & Dong, 2007). CMC-Na is usually used as a water-soluble thickener, emulsifier and film-former in biomedical membrane and tablet coating (Salum et al., 2006). MCC could form a stable gel in water with a great number of special properties such as oil absorption, large surface area, non-toxicity, biodegradability, low density and biocompatibility, etc (Miao & Hamad, 2013; Yang, Tang, Wang, Kong, & Zhang, 2014; Zulkifli, Samat, & Anuar, 2015). It also exhibits a unique capacity to improve the morphology, thermal and mechanical properties of the composite (Xiao, Qi, Zeng, Yuan, & Yu, 2014). MCC is difficult to disintegrate once dried because the hydrogen bonds in MCC cause strong adhesion between the individual micro fibrils (Comunian, Thomazini, Alves, Balieiro, & Favaro-Trindade, 2013). So far, there is no report available on the use of the CMC-Na and MCC for astaxanthin encapsulation. It is useful to minimize the aforementioned disadvantages of free astaxanthin, which is favorable to be used in the food, cosmetology, and medicine industry.

Natural bioactive compounds have been increasing focus with the development of society compared with synthetic chemicals. However, it is also important to choose a suitable food product for the encapsulated astaxanthin. Yogurt, a daily consumed healthy, nutritious and tasty dairy, is rich in vitamins, minerals, calcium and proteins (Panagiotidis & Tzia, 2001). More importantly, it can deliver probiotics to improve the health of consumers. However, yogurt is deficient in total antioxidant activity and stability (Krasaekoopt, Bhandari, & Deeth, 2006). It is necessary to develop new functional yogurt to meet people's appetite and market requirements. Therefore, the study on the encapsulation of astaxanthin with CMC-Na/MCC to improve the total antioxidant activity of yogurt and its stability for longer shelf life is meaningful.

In the present work, the stability and properties of astaxanthin from P. rhodozyma was investigated by encapsulation with MCC and sodium CMC-Na. Additionally, the effects of the microencapsulated astaxanthin on yogurt properties were also examined in terms of storage stability, color, DPPH-scavenging activity, total number of lactic acid bacteria and acidity.