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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, flowability 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 findings, microencapsulated CV peptides is a valuable source of BACs in functional formulations.

In the recent years, extensive research is under way about the use of natural bioactive compounds and production of functional foods to increase community health and reduce the risk of various food...

Brassica vegetables, particularly turnip, contain many natural antioxidants. This review focuses on antioxidant components and the influence of different processing and storage conditions on antioxidant activities of some Brassica vegetables including turnip. Long storage times had an adverse effect on antioxidant value of turnip. Also, the activity of antioxidants in cruciferous vegetables could be influenced by antioxidant breakdown and leaching during cooking. Heat treatment has a major impact on the antioxidant activity of Brassica vegetables and it has been perceived minor antioxidant ability in processed vegetables compared with uncooked samples. Food processing operations in terms of blanching, canning, sterilizing and freezing, in addition to cooking methods perhaps can have a major influence on the yield, chemical structure and bioavailability of antioxidants in Brassica family. Cooking methods such as steaming and microwaving are proper methods for a short time. Consumption of raw or slightly blanched turnip is an appropriate way to maximize its health benefits.

Our main goal was to encapsulate oleuropein within double nano-emulsions stabilized by pectin-whey protein concentrate (WPC) complexes and prepared by sonication. Five independent variables including surfactant (Span) content, WPC and pectin content, ratio of inner to outer phase, and pH were considered along with size of emulsion droplets, zeta potential, and encapsulation efficiency as the dependent variables. Optimum conditions were determined as, 8% WPC, 1.97% pectin, 8.74% Span, 1:4 ratio of inner to outer phase and pH = 6.1. After 28 days storage, double emulsions loaded with oleuropein (260, 520, 780 and 1040 μg/mL) released approximately 39.9, 40.2, 42.2 and 42.9% of their total content. The results of oleuropein release after 28 days determined by HPLC (40.4%) were consistent with those obtained spectrophotometrically (42.9%). To produce double emulsions with the highest load, samples with 1040 (μg/mL) oleuropein were produced according to the optimum conditions and a droplet size of 191 nm, zeta potential of −26.8 mV, and encapsulation efficiency of 91% was achieved. SEM results showed particles with smooth, relatively spherical, somewhat asymmetrical surfaces with a size range of 100–200 nm compatible with dynamic light scattering results.

Water-in-oil-in-water (W1/O/W2) double emulsions are one of the most efficient nutraceutical delivery systems. Our main objective was to compare some emulsion properties of double nano-emulsions loaded with gallic acid in W1 phase. Polyglycerol polyricinoleate (PGPR), and pectin-WPC or/Tween 80 were applied as emulsifiers in W1-O and O-W2 interfaces, respectively. Our results revealed that complex of pectin-WPC had the same resistance against sedimentation and creaming as Tween 80. The particle size of double emulsions produced by Tween 80 and pectin-WPC were in the range of 98–577 and 100–1520 nm, respectively. Z-potential of double emulsions prepared with pectin-WPC were more negative than −30 mV; so they were more stable during the long term storage. The optimum conditions for preparing WPC-pectin stabilized delivery systems were determined as 5, 75 and 20 (wt. %) PGPR, soybean oil and deionized water, respectively for internal W1/O nano-emulsion; and 1, 4, 79 and 16 (wt. %) pectin, WPC, deionized water, and internal nano-emulsion, respectively for the W1/O/W2 emulsions. Student's t-test analysis revealed that except for z-potential, there were no significant differences between emulsifiers (pectin-WPC and Tween 80). The present study demonstrates that pectin-WPC complex can be used as an appropriate emulsifier comparable with Tween 80 for stabilizing double emulsions.

Many properties of various nanocarriers, such as physicochemical stability, encapsulation efficiency, loading capacity, bioactive compound position inside the nanoparticles, bioavailability, bio-distribution, release kinetics, and cellular uptake of the loaded ingredients, are considerably influenced by the size and shape of nanocarriers. On the other hand, it is necessary to evaluate the surface and morphological structure of nanocarriers for formulation optimization, functionalization of nanoparticles/nanocomposite structures, production process variables, as well as the elimination of the nanocarrier disadvantages (like nanoparticle coagulation/aggregation, unfavorable size, and existence of pores and cracks on the surfaces of nanoparticles/nanocomposites). Scanning electron microscopy (SEM) is one of the most important methods of investigating the morphological and surface structure of nanocarriers. Considering the above-mentioned cases, the objective of this chapter is exploring the importance of SEM in characterizing delivery systems, evaluating the scales of nanocarriers, methods of morphological examinations, advantages, disadvantages, and SEM applications in the study of structural properties of various nanocarriers (lipid-based, protein/polysaccharide-based, nanofibers and nanotubes, mesoporous nanoparticles, nanocomposites, and other nanostructures).