Preparation Of Ferrous Gluconate-Loaded Solid Lipid Nanoparticles And Its Property Changes Induced By Peptides From Myofibrillar Protein Hydrolysates

Iron, playing a significant role in material metabolism and energy metabolism of organism, is one of the essential trace elements for human beings. Ferrous ion, as the major form of non-heme iron in dietary, has a low bioavailability due to the complexation with phytic acid, oxalic acid, polyphenols and such iron inhibitors in foods. It’s usually unlikely that human get adequate iron from commo n dietary. Therefore, preparation of iron supplementation can be a candidate method of preventing the complexation of iron and its inhibitors, enhancing the bioavailability and addressing the issue of iron deficiency.The preparation of ferrous gluconate(FG) solid lipid nanoparticles(SLN) and the key factors which affected the production of SLN were investigated in this study; the effects of polysaccharides/monosaccharide on the entrapment efficiency, physicochemical properties such as average size, polydispersity index(PDI) and zeta potential, and release profile were evaluated. The myofibrillar protein, which was widely believed containing the candidate of meat factor, from pork muscle was also extracted and digested by various enzymes. The molecular distribution, composition and contents of amino acids of the resulting hydrolysates were analyzed as well as the iron-chelating ratio. The possibility of peptide involved in the SLN was also explored aiming to product the iron supplementation with higher bioavailability.Firstly, the FG-SLN was prepared by W/O/W double emulsion method. The influences of volume ratio of aqueous/oil phase of internal phase, outer/ inner phase and concentration of lecithin consumed on the entrapment efficiency of SLN were invest igated. The maximal entrapment efficiency, 52.48%, was obtained under the circumstances of 0.2 as the volume ratio of aqueous/oil phase of internal phase, 5:1 as the volume ratio of outer/ inner phase and 5% as the concentration of lecithin consumed. The e ffects of soybean lecithin on the average size and PDI were also studied.Then, the effects of three anionic polymers/organic salt solvent, sodium alginate(SA), glucosamine hydrochloride(GH) and dextran sulfate(DS), on the partition coefficient were investigated and the results showed that the additions of such polymers/organic salt into FG solution were in favor of the lipophilicity of iron. With the weight ratio of 1:2 to FG, SA, DS and GH posed a positively impact on the entrapment efficiency, which was 59.03%, 54.06% and 61.30%. Though slight changes were observed in terms of average size and PDI, the absolute values of zeta potential of all polymer hybrids SLN increased. Differential scanning calorimetry(DSC) diagram of SLNs showed the changes of the enthalpy(?H) and peak temperature(Tp) took place, which meant the degree of crystallization decreased. In vitro release profile showed that SLNs could keep integrity in simulated gastric fluid(SGF) and went through a burst release in simulated intestinal fluid(SIF). Therefore, SLN could protect the drug from disintegration and release in the active site.Finally, the myofibrillar protein from pork muscle was extracted and the sodium dodecyl sulfate polyacrylamide gel electrophoresis(SDS-PAGE) was applied to analyze the effects of various enzymes on myofibrillar protein aiming to get the similar enzymatic process with pepsin, which stood for the gastrointestinal digest of protein in vivo. Through comparing the peptide yield ratio and degree of hydrolys is, enzymatic hydrolysis starting with Protin SD-AY(SD) for 4 h, followed by digests with other bacterial enzymes, Protease P(PP) for 12 h was chosen economically. The results of relative molecular weight and composition of amino acids in hydrolysates from pepsin and the combine enzymes showed that the hydrolysates from pepsin had higher weight ratio of aspartic acid and glutamic acid and higher ironchelating ratio with 13.53%. The possibility of introducing high iron-binding peptides into SLN resulting from hydolysates was explored as well. It was found that the entrapment efficiency decreased significantly with the addition of peptides and average size and absolute zeta potential of SLN increased in the meantime. However, the release profile of SLN didn’t change only with the higher release ratio in both SGF and SIF. The storage experiment showed that the drug remaining ratio in 4℃ is higher than in 25℃, and the average size of SLN except peptide hybrid SLN didn’t alter significantly.