Coordination Of β-cyclodextrin And Chitosan Derivatives To Improve The Stability Of Anthocyanins And Its Application In Food

Anthocyanins(ACNs)are a subclass of water-soluble flavonoids compounds,natural pigments found in plants(berries,fruits and vegetables)with excellent biological activities such as antioxidant,anti-inflammatory,anti-obesity,anti-diabetic and anti-cancer.ACNs can be added to foods as natural colorants.However,the poor stability and low bioavailability of ACNs have limited their application in food products.To improve the stability of ACNs,in this thesis,we prepared ACN-loaded nanocomplex particles(ACN-loaded β-CDCHC/CMC)by self-assembly using β-cyclodextrin(β-CD)and two water-soluble chitosan derivatives,namely chitosan hydrochloride(CHC)and carboxymethyl chitosan(CMC).In previous studies,β-CD and chitosan were used in combination,mainly to improve the loading capacity to hydrophobic drugs.In this study,CMC,CHC and β-CD were tested as nanocarrier materials for the encapsulation of hydrophilic bioactive substances(ACNs)by self-assembly.The main research contents and results are as follows:1.The ACN-loaded β-CD-CHC/CMC nanocomplexes were prepared using ACNs extract as the core material and β-CD and two chitosan derivatives(CHC/CMC)as the wall material,and the effects of CHC concentration,pH of the system and the concentration ratio of ACNs on the retention of ACNs in nanocomplexes were investigated by single-factor tests.The results showed that the retention of ACN-loaded β-CD-CHC/CMC nanoparticles was 57.52%,the particle size of nanocomplexes was 333.86 nm,the zeta potential was 45.97 mV and the PDI value was 0.15 at the β-CD concentration was 0.82 mg/mL,CMC concentration was 0.4 mg/mL,CHC concentration of 3.0 mg/mL,the pH of the system was 3.8 and the ACNs concentration was 0.2 mg/mL.2.Morphological characterization,physicochemical characterization and stability studies of ACN-loaded β-CD-CHC/CMC nanocomplexes.The ACNs nanocomplexes showed a morphological modification after the inclusion process as observed by SEM and the spherical morphology of the nanocomplexes was observed by scanning electron microscopy(SEM)and transmission electron microscopy(TEM).Fourier transform infrared(FT-IR)spectroscopy,Raman spectroscopy,X-ray diffraction(XRD)and nuclear magnetic resonance hydrogen spectroscopy(1H NMR)analysis techniques determined the layer-bylayer self-assembly between the substances in the nanocomplexes mainly through hydrogen bonding and electrostatic interactions.The nanocomplexes showed good stability under four adverse environmental stresses of higher temperature,light,neutral pH and and ascorbic acid(AA),respectively3.The release behavior and stability of ACNs in ACN-loaded β-CD-CHC/CMC nanocomplexes under simulated gastrointestinal conditions.The results showed that the stability of ACNs in ACN-loaded β-CD-CHC/CMC nanocomplexes was improved and slow-release properties were observed compared with unencapsulated ACNs.4.Research on the application of ACN-loaded β-CD-CHC/CMC nanocomplexes in food products.ACN-loaded β-CD-CHC/CMC nanocomplexes were added to simulated electrolyte beverage systems(pH=3.5)and milk teas(pH=6.8)to evaluate the storage stability of ACNs-rich beverages,and the results showed that the addition of ACN-loaded βCD-CHC/CMC nanocomplexes to beverages and milk teas resulted in ACNs storage stability and thermal stability were improved.In addition,the nanoparticles loaded with ACNs were used to prepare high internal phase emulsions by increasing the concentrations of β-CD and chitosan,and the results showed that at a solution ratio of 3:1 between flaxseed oil and ACN-loaded β-CD-CHC/CMC nanocomplex,β-CD concentration of 1.2 wt%,chitosan concentration of 0.44 wt%,the high internal phase emulsion with good centrifugal stability and rheological properties.