Phycocyanin stability in microcapsules processed by spray drying method using different inlet temperature

Microalgae: A Promising Source of Bioactive Phycobiliproteins

Phycobiliproteins are photosynthetic light-harvesting pigments isolated from microalgae with fluorescent, colorimetric and biological properties, making them a potential commodity in the pharmaceutical, cosmetic and food industries. Hence, improving their metabolic yield is of great interest. In this regard, the present review aimed, first, to provide a detailed and thorough overview of the optimization of culture media elements, as well as various physical parameters, to improve the large-scale manufacturing of such bioactive molecules. The second section of the review offers systematic, deep and detailed data about the current main features of phycobiliproteins. In the ultimate section, the health and nutritional claims related to these bioactive pigments, explaining their noticeable potential for biotechnological uses in various fields, are examined.

Physicochemical and Biological Characterization of Encapsulated Olive Leaf Extracts for Food Preservation

Phenolic compounds in olive leaves have an excellent antioxidant activity and good antimicrobial properties. These bioactive molecules have beneficial properties for health, arousing great scientific and commercial interest. This study reports lyophilized olive leaf extracts (OLE) encapsulated by spray-drying using maltodextrins, maltodextrins-pectin and maltodextrins-gum Arabic as encapsulating agents. Lyophilized OLE were collected from two varieties cultivated in a harsh pedo-climatic conditions of the arid region of Tunisia. The effects of the genetic factor and the different encapsulating agents on the physicochemical properties of microcapsules and their behavior during storage, as well as their antimicrobial activities, were studied. Microcapsules successfully passed heat treatment and storage conditions and their antimicrobial activities were preserved. The encapsulating agent combination improved the encapsulation efficiency and the product yield in Zarrazi variety compared to Dhokar one. In addition, Dhokar variety microparticles showed the best heat stability at 4 and 25 °C after 90 days of storage and the higher inhibition percent against bacteria. The results of the present study evidenced that the best conditions for OLE encapsulation were obtained when the maltodextrins-pectin and maltodextrins-gum Arabic were combined to form a hybrid coating material.

Preparation and Characterization of Mg-Doped Calcium Phosphate-Coated Phycocyanin Nanoparticles for Improving the Thermal Stability of Phycocyanin

Phycocyanin (PC) is a blue-colored, pigment-protein complex with unique fluorescence characteristics. However, heat leads to PC fading and fluorescence decay, hampering its widespread application. To improve the thermal stability of PC, we induced the in situ mineralization of calcium phosphate (CaP) on the PC surface to prepare PC@Mg-CaP. The nanoparticles were characterized using transmission electron microscopy, energy dispersive spectrometry, fourier transform infrared spectroscopy, and X-ray diffraction. The results showed that PC@Mg-CaP was spherical, and the nanoparticle size was less than 200 nm. The shell of PC@Mg-CaP was composed of amorphous calcium phosphate (ACP). The study suggested that CaP mineralization significantly improved the thermal stability of PC. After heating at 70 °C for 30 min, the relative concentration of PC@Mg-CaP with a Ca/P ratio = 2 was 5.31 times higher than that of PC. Furthermore, the Ca/P ratio was a critical factor for the thermal stability of PC@Mg-CaP. With decreasing Ca/P, the particle size and thermal stability of PC@Mg-CaP significantly increased. This work could provide a feasible approach for the application of PC and other thermal-sensitive biomolecules in functional foods requiring heat treatment.

Microencapsulation of probiotics in finger millet milk complex to improve encapsulation efficiency and viability

This study aimed to assess the effectiveness of finger millet milk complex (almond gum with maltodextrin) to encapsulate the isolated Lactobacillus strains. The wall materials were optimized based on its encapsulation efficiency, antioxidant activity, total phenol content and encapsulation yield. The strains were spray-dried at the optimized condition: 120 °C inlet temperature, maltodextrin 30% and almond gum 1.5%. Survival count of microencapsulated Lactobacillus plantarum RS09 and RS23 strains were 7.91 and 7.83 CFU/g respectively. Viability of microencapsulated strains and free cells under low pH, bile salt, simulated gastric juice and intestinal juice were assessed. Strain RS09 exhibited the highest viable count. Addition of almond gum and finger millet milk increased the phenolic content and offered a protective effect to the strains during spray drying. Results also showed that the powders were amorphous with partial irregularities and a smooth surface with less dents. Hence, they could be used as potential encapsulating agents during spray drying.

A novel method for double encapsulation of C-phycocyanin using aqueous two phase systems for extension of shelf life

Spirulina platensis is having high nutritive value due to pigments such as chlorophyll-a, phycobiliproteins (especially phycocyanins) and carotenoids. In our present work, C-phycocyanin (C-PC) was extracted from dry biomass of Spirulina platensis. C-PC being heat sensitive, reiterates the need for additional protection during drying (micro encapsulation). Accordingly, a novel method employing aqueous two phase systems (ATPSs) as carrier materials to achieve double encapsulation was studied for the first time. PEG 4000/Potassium phosphate and PEG 6000/Dextran were used at already standardized tie line length, at different volume ratios (by varying the total phase composition). ATPS at each volume ratio acted as different carrier materials offering varied degree of heat protection during double encapsulation while maltodextrin, being the conventional carrier material, was used for comparison. The best results of spray dried powders using PEG (4% w/w)/Potassium phosphate salt (18%, w/w) and PEG (6%)/Dextran (10%, w/w) phase systems as carrier materials were compared with conventional encapsulation (MDX as a carrier material) and freeze dying as control. PEG/Dextran as a carrier material with volume ratio of 0.25 resulted in the highest retention of blue colour (b*value), purity (0.43) as well as yield (Y_EP) of 94.99% w/w of C-PC, which could be stored for 6 months without much reduction from initial powder characteristics. From the overall results, it can be concluded that ATPS can be used as an effective carrier material for double encapsulation of biomolecules such as C-PC with additional benefit of enhancing the purity.