Bioaccessibility of different types of phenolic compounds co-encapsulated in alginate/chitosan-coated zein nanoparticles

Simultaneous administration of different phenolic compounds might produce a synergistic effect offering a greater activity against chronic non-communicable diseases. This has prompted significant interest in developing nanodelivery systems that simultaneously encapsulate different bioactives and protect them from gastrointestinal digestion. This work aimed at evaluating the suitability of zein (ZN) and zein/polysaccharide-based nanoparticles to co-encapsulate different types of phenolic compounds and understand how increasing the complexity of the nanoparticulate systems affected the bioaccessibility of the polyphenols. Two phenolic acids, two glycosylated flavonoids, and three flavonoid aglycones were successfully co-encapsulated in the three nanoparticulate systems. The encapsulation efficiency of phenolic compounds loaded on ZN ranged between 95.3 and 98.5%. The incorporation of the coating-layers (alginate – algZN- and chitosan –alg/chiZN-) significantly increased the encapsulation efficiency of phenolic acids and glycosylated flavonoids. The bioaccessibility of phenolic compounds loaded on ZN increased by at least 50.2%. Enhanced bioaccessibility of phenolic acids and glycosylated flavonoids was observed upon coating with alginate, while the greatest polyphenol bioaccessibility was seen for the alg/chiZN (over 65.8%). The greatest bioaccessibility was observed for polar phenolic acids, followed by glycosylated flavonoids. Therefore, the developed systems could be potentially useful to co-encapsulate different types of phenolic compounds and to improve their bioaccessibility.This work was financially supported by National Fund for Scientific & Technological Development (FONDECYT), project Nº1211803, International Cooperation Program from National Agency of Research and Development (ANID) projects REDI Nº170441 and REDES Nº180178, and Fund for Scientific and Technological Equipment (FONDEQUIP) project Nº130209.Peer reviewe

Genetic diversity and comparison of physicochemical and nutritional characteristics of six quinoa (Chenopodium quinoa willd.) genotypes cultivated in Chile

The present study was focused on the analysis of agronomical, nutritional, physicochemical, and antioxidant properties of six genetically different quinoa (Chenopodium quinoa Willd) genotypes cultivated in three distinctive geographical zones of Chile. Ancovinto and Cancosa genotypes from the northern Altiplano (19 ºS), Cáhuil and Faro from the central region (34 ºS), and Regalona and Villarica from the southern region (39 ºS) are representative of high genetic differentiation among the pooled samples, in particular between Altiplano and the central-southern groups. A Common-Garden Assay at 30 ºS showed significant differences among seed origins in all morphometric parameters and also in yields. Altiplano genotypes had larger panicule length but no seed production. A significant influence of the different quinoa genotypes on chemical composition and functional properties was also observed. Protein concentration ranged from 11.13 to 16.18 g.100 g-1 d.m., while total dietary fiber content ranged from 8.07-12.08 g.100 g-1 d.m., and both were the highest in Villarrica ecotype. An adequate balance of essential amino acids was also observed. Sucrose was the predominant sugar in all genotypes. Antioxidant activity was high in all genotypes, and it was highest in Faro genotype (79.58% inhibition)

Impact of molecular weight and deacetylation degree of chitosan on the bioaccessibility of quercetin encapsulated in alginate/chitosan-coated zein nanoparticles

This work aimed at studying the effect of molecular weight (MW) and deacetylation degree (DD) of chitosan on the quercetin bioaccessibility encapsulated in alginate/chitosan-coated zein nanoparticles (alg/chiZN). The chitosan coating layer produced nanoparticulate systems with good stability parameters, high encapsulation efficiency (EE) and a higher bioaccessibilty of quercetin after in-vitro digestion. By increasing the DD of chitosan, the ζ-potential of the colloidal system significantly increased (≥27.1 mV), while low and very low MW chitosans generated systems with smaller particle sizes (≤ 277.8 nm) and polydispersity index [PDI (0.189)]. The best results, in terms of EE (≥84.44) and bioaccessibility (≥76.70), were obtained when the systems were prepared with low MW chitosan and high DD. Thus, the alg/chiZN nanocapsules may be a promising delivery system for improving the quercetin bioaccessibility or other compounds with a similar chemical nature, especially when higher DD and lower MWs are used.This work was financially supported by National Fund for Scientific & Technological Development (FONDECYT), projects No 1211803 and No 1201658, project FOVI210081, and Fund for Scientific and Technological Equipment (FONDEQUIP) project No. 130209.Peer reviewe

Characterization of Lactobacillus fermentum UCO-979C, a probiotic strain with a potent anti-Helicobacter pylori activity

Background: Helicobacter pylori is considered as the main risk factor in the development of gastric cancer. In the present study, we performed a detailed characterization of the probiotic properties and the anti-H. pylori activity of a previously isolated lactobacillus strain — Lactobacillus fermentum UCO-979C — obtained from human gut. Results: The strain tolerated pH 3.0; grew in the presence of 2% bile salts; produced lactic acid and hydrogen peroxide; aggregated in saline solution; showed high hydrophobicity; showed high adherence to glass; Caco-2 and gastric adenocarcinoma human cells (AGS) cells; showed an efficient colonization in Mongolian Gerbils; and potently inhibited the growth and urease activity of H. pylori strains. L. fermentum UCO-979C significantly inhibited H. pylori-induced IL-8 production in AGS cells and reduced the viability of H. pylori. With regard to innocuousness, the strain UCO-979C was susceptible to several antibiotics and did not produce histamine or beta-haemolysis in blood agar containing red blood cells from various origins. Conclusion: The results demonstrated that L. fermentum UCO-979C is a very good candidate as a probiotic for the protection of humans against H. pylori infections

Multivariable optimization of ultrasound-assisted extraction for the determination of phenolic and antioxidants compounds from arrayan (Luma apiculata (DC.) Burret) leaves by microplate-based methods and mass spectrometry

The present study reports a multivariable optimization of ultrasound-assisted extraction of phenolic compounds from arrayan leaves. The parameters ethanol percentage in extraction solvent, temperature and extraction time, and mass to solvent ratio were optimized applying full factorial and central composite designs. According to the models, the optimal extraction conditions were: 42% of ethanol, extraction time of 27 min, extraction temperature of 50ºC and a mass to solvent ratio of 1:33.4 g mL-1. Under these conditions, a total phenolic content (TPC) of 128.16±1.18 and 593.64±6.49 mg of gallic acid equivalent per g of dry weight (DW) were determined in raw extract (RE) and polyphenols-rich extract (PRE), which was obtained by semi-preparative chromatography on XAD-7 column. Antioxidant capacity determined via FRAP analysis showed values of 1349.53±28.99 and 6175.47±127.64 µmol Trolox equivalent per g of DW for RE and PRE, and DPPH IC50 values of 831.40±0.80 and 132.21±2.51 µg mL-1, respectively. Polyphenols profile analyzed by liquid chromatography-mass spectrometry showed the presence of quercetin 3-ß-D-glucoside, myricetin, quercetin, kaempferol 3-glucoside and gallic acid; the latter compounds are reported for the first time in arrayan leaves. Due to the presence of polyphenols, antiviral activity was assayed over norovirus and hepatitis A showing a significant dose-dependent effect.This work is part of Jonathan Carrasco Sandoval thesis to obtain the degree of Doctor in Analytical Science and Technology from the University of Concepcion, Chile. Authors want to thank to National Agency of Research and Development (ANID) of the Chilean Government for the doctoral scholarship granted. Special thanks to Prof. Herbert. W. Virgin from Washington University School of Medicine, USA, for kindly provide RAW 264.7 cell lines.Peer reviewe