Effect of Chemical Degradation of Sodium Alginate on Capsaicin Encapsulation.

Capsaicin is known as an oily extract of paprika that is characterized by pungent taste and bioactivity. It also may cause irritation to the mouth and stomach which is why is so important to immobilize capsaicin on a carrier to prevent it. The usage of alginate oligomers, which has an antioxidant potential compared to alginate, is of benefit because it may be used in the immobilization of bioactive substances that are fragile to oxidation. The purpose of this study was to use sodium alginate oligomers as a coating material in the encapsulation process of paprika oleoresin. Alginate oligomers were produced by chemical degradation with hydrogen peroxide. The characteristics of the samples were obtained by measuring the viscosity, the contact angle of the surface, and the surface tension of solutions. The obtained solution of alginate oligomers served as the carrier material for the immobilization of capsaicin. Capsules were prepared by ionic gelation using a calcium chloride solution as a crosslinking agent. In this way, capsules without and with the core (capsaicin) were prepared and their ability to scavenge free radicals (DPPH) and iron-reducing properties (FRAP) were determined. The stability of the capsules was examined by thermal decomposition and under conditions of the gastric and small intestine, and capsaicin content was detected using high-performance liquid chromatography. It was found that alginate oligomers could be used in the encapsulation of bioactive compounds and the efficiency was above 80%. Capsule production from alginate oligomers affected their thermal stability. The use of alginate derivatives as a carrier increased the antioxidant properties of the finished product, as well as its ability to reduce iron ions. The use of alginate oligomers as a coating material prevented the active substance from being released too early in the conditions of the small intestine, prolonged the stability of the capsules, and supported their durability in gastric conditions.

Functional Properties of Chitosan Oligomers Obtained by Enzymatic Hydrolysis.

The aims of this study were to obtain chitooligosaccharides (COS) from chitosan (CH) with improved functional properties and comparison of the use of two different enzymes: commercial cellulase (CL) and the dedicated enzyme chitosanase (CS). After enzymatic reaction, chitosan oligomers (NFs) were isolated by methanol into two fractions: precipitate (HMF) and supernatant (LMF). The occurrence of a hydrolysis reaction was confirmed by an increased reducing sugar content and viscosity reduction of chitosan oligomers. CPMAS 13C NMR analysis confirmed the dissimilar cleavage mechanism of the enzymes used. LMF and NF fractions were characterised by improved solubility in water (94.56%) compared to the HMF and CH samples (70.64%). Thermogravimetric analysis (TGA) showed that the HMF decomposed in two-stage process while CH, NF, and LMF decomposed in a three-stage process. The greatest mass loss of LMF samples (58.35%) suggests their sensitivity to high-temperature treatments. COS were a mixture of DP (degrees of polymerisation) from 3 to 18 hetero-chitooligomers, with an average Mw of <3 kDa. CL consisted of more low-DP products (DP 3-7) than COS made with CS. LMF characterised by DP~2 showed lower DPPH radical scavenging activity than HMF and NF with DP 3-7. The ability to reduce Escherichia coli increased in the given order: LMF > NF > HMF > CH.

Biophysico-Chemical Properties of Alginate Oligomers Obtained by Acid and Oxidation Depolymerization.

The aim of the study was to obtain alginate oligosaccharides by using two degradation methods of sodium alginate (SA): with hydrochloric acid (G-guluronate, M-mannuronate and G + M fractions) and hydrogen peroxide (HAS-hydrolyzed SA), in order to assess and compare their biological activity and physico-chemical properties, with an attempt to produce gels from the obtained hydrolysates. The efficiency of each method was determined in order to select the fastest and most efficient process. The ferric ion reducing antioxidant power (FRAP), the ability to scavenge DPPH free radicals, rheological properties, Fourier Transformed Spectroscopy (FTIR) and the microbiological test against Escherichia coli and Staphylococcus aureus were performed. In order to check the functional properties of the obtained oligosaccharides, the texture profile analysis was assessed. The hydrolysis yield of acid SA depolymerization was 28.1% and from hydrogen peroxide SA, depolymerization was 87%. The FTIR analysis confirmed the degradation process by both tested methods in the fingerprint region. The highest ferric reducing antioxidant power was noted for HSA (34.7 µg), and the highest hydroxyl radical scavenging activity was obtained by G fraction (346 µg/Trolox ml). The complete growth inhibition (OD = 0) of alginate hydrolysates was 1%. All tested samples presented pseudoplastic behavior, only HSA presented the ability to form gel.

The Effect of Using Micro-Clustered Water as a Polymer Medium.

The aim of the study was to investigate the changes within the physicochemical properties of gelatin, carrageenan, and sodium alginate hydrosols prepared on the basis of micro-clustered (MC) water. The rheological parameters, contact angle and antioxidant activity of hydrosols were investigated. Moreover, the pH, oxidation-reduction potential (ORP) and electrical conductivity (EC) were measured. The hydrosols with MC water were characterized by a lower pH, decreased viscosity, a lower contact angle, and only slightly lower antioxidant activity than control samples. The results showed that hydrosol's properties are significantly changed by MC water, which can lead to enhancement of its applicability but requires further investigation.

The enhancement of plant secondary metabolites content in Lactuca sativa L. by encapsulated bioactive agents.

Encapsulated bioactive agents applied to the Lactuca sativa L. present an innovative approach to stimulate the production of plant secondary metabolites increasing its nutritive value. Calcium and copper ions were encapsulated in biopolymeric microparticles (microspheres and microcapsules) either as single agents or in combination with biocontrol agents, Trichoderma viride spores, a fungal plant growth mediator. Both, calcium and copper ions are directly involved in the synthesis of plant secondary metabolites and alongside, Trichoderma viride can provide indirect stimulation and higher uptake of nutrients. All treatments with microparticles had a positive effect on the enhancement of plant secondary metabolites content in Lactuca sativa L. The highest increase of chlorophylls, antioxidant activity and phenolic was obtained by calcium-based microparticles in both, conventionally and hydroponically grown lettuces. Non-encapsulated fungus Trichoderma viride enhanced the synthesis of plant secondary metabolites only in hydroponics cultivation signifying the importance of its encapsulation. Encapsulation proved to be simple, sustainable and environmentally favorable for the production of lettuce with increased nutritional quality, which is lettuce fortified with important bioactive compounds.