Stabilization of Chlorella Bioactive Hydrolysates Within Biopolymeric Carriers: Techno-functional, Structural, and Biological Properties

Abstract

Chlorella vulgaris (CV) is a green unicellular microalga with various bioactive compounds (BACs) and is highly appreciated due to its variety of biological activities. Among different sources, bioactive peptides have positive biological effects and numerous health-promoting properties. However, instability, reactivity and high bitterness are the main challenges which may restrict the application of these components in preparation of diverse food compounds. Therefore, the present investigation stresses on the capability of the gum arabic (GA), maltodextrin (MD), pectin (PE) and alginate (AL), and combinations of them as carrier agents on physicochemical, techno-functional, structural and activity of spray-dried CV peptides. Biological indices were affected by the degree of hydrolysis and free amino acid values. The alteration in physico-chemical, functional, owability along with color characteristics may be associated with composition of the carriers. MD-AL combination showed the best performance on the mentioned indicators, physical stability and scavenging the ABTS (84%) and DPPH (77%) radicals of spray-dried (SD) peptides. The chemical structures (FTIR analysis) indicated the placement of peptides in the carrier matrix. SEM images of SD particles revealed wrinkled, irregular and hollow structures (matrix-type microsphere) in different sizes. Referring to the ndings, microencapsulated CV peptides is a valuable source of BACs in functional formulations. MaterialSample (Chlorella powder) was purchased from Iranian National Algae Culture Collection (INACC). The chemicals including alcalase, pancreatin, trypsin, pepsin (Novo Nordisk, Bagsvaerd, Denmark), diammonium salt, copper (II) sulfate, ABTS (2,2′-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid), ferrous chloride, Ammonium heptamolybdate, DPPH (1,1-Diphenyl-2-picrylhydrazyl), Sodium phosphate tribasic, Pyridine and Pyrocatechol violet were obtained from Sigma-Aldrich Co. (St. Louis, MO, USA). Potassium ferricyanide, trichloroacetic acid (TCA), sodium hydroxide, potassium persulphate and other antioxidant reagents were purchased from Merck (Germany). Alpha-deoxyribose was purchased from Fluka (Stockholm, Sweden). Other chemicals used were of analytical grade. ExtractionThe process of protein extraction was done for 1h by mixing algae powder (at a ratio of 1:10 w/v) in the distilled water solution comprising 0.3 M sodium chloride (after regulating the mixture pH to 10 with 1N NaOH). The attained dispersion was centrifuged (5,000 × g for 20 min) and the soluble proteins in the supernatant were precipitated after adjusting the pH to 4.20.5 M HCl. Lastly, the centrifuged mixture and the extracted proteins were freeze-dried (Feyzi et al., 2018). The Hydrolysis Using EnzymesThe hydrolysis by means of enzymes was done in proportion to the technique explained by Sarabandi et al. ( 2018) with minor amendments. Prepared samples were dissolved in the 0.01 M phosphate buffer saline at a ratio of 5% (w/v) for 30 min. Then, the enzymatic hydrolysis was carried out using alc...

Incorporation of spray‐dried encapsulated bioactive peptides from coconut (Cocos nucifera L.) meal by‐product in bread formulation

“…The efficiency and performance of each carrier generally depend on factors such as ease of access, price, viscosity in solution, food grading, solubility, ability to form a film/shell and increase in glass transition temperature (Tg) (Akbarbaglu, Tamjidi, et al., 2023). Moreover, the activity of carriers in preventing conformational changes and maintaining the biological activity of peptides during shear stresses and dehydration during atomization and drying is of paramount importance (Gharehbeglou et al., 2023).…”