In vitro characterization of chitosan scaffolds: influence of composition and deacetylation degree

In this study, the influence of degree of deacetylation (DD) and composition on some structural and biological properties of chitosan scaffolds were examined in vitro. 3D chitosan scaffolds of 2% (w/v) and 3% (w/v) composition in different DDs i.e. 75–85% and >85% were prepared by freeze-drying method at −80 °C. We noticed that >85% deacetylated chitosan scaffolds of 2% (w/v) composition has a highly interconnected morphological structure having ∼100 μm pore size with 0.0917 N/mm² compression modulus. L929 fibroblastic cells were cultured on chitosan scaffolds in order to evaluate their biocompatibilities. Cell culture studies demonstrated that fibroblastic cell attachment and proliferation is affected by DD. The higher deacetylated chitosan scaffolds strongly supported the attachment and proliferation when compared with the lower deacetylated scaffolds. MTT assay indicated that >85% deacetylated chitosan scaffolds of 2% (w/v) composition, having the highest specific growth rate 0.017 h⁻¹ of all, was found to be the most suitable for cell culture studies and a potential candidate for tissue engineering with enhanced biostability and good biocompatibility.     

Parametric characterizations in superparamagnetic latex

The effect of synthesis parameters on the production of superparamagnetic latex, which are magnetite nanoparticles covered with a poly(methyl methacrylate) layer, were studied. The synthesis method was based on the developed route of emulsifier-free emulsion polymerization. Under this study, effects of the monomer and initiator concentrations, the amount of magnetic sol, the stirring rate and the adding rate of the magnetic sol on the properties of synthesized latexes were investigated. The characterizations were performed by a high resolution transmission electron microscopy, a dynamic light scattering, a vibrating sample magnetometer and a gel permeation chromatography. The results showed that the monomer concentration was found to be the most effective parameter on latex stability. As the initiator amount and the stirring rate increased, saturation magnetization and average molecular weight decreased due to the reactions occurring between surfaces of magnetite nanoparticles and initiator fragments. On increasing amount of magnetic sol, the saturation magnetization and polymer molecular weight increased but the size of nanospheres was unchanged because of the ions in magnetic sol. It was seen that the desired size and magnetic properties of the latex could be obtained since the parameters were found to have substantial impact on their properties.     

Sour Cherry By-products: Compositions,Functional Properties and Recovery Potentials – A Review

Abstract

Sour (tart) cherry is an industrial fruit where a considerable amount of by-products remain after processing. Sour cherry by-products consist of pomace (skin and flesh) and seeds (pit, stone) which remain after the fruit juice and IQF processes. Sour cherry pomace is characterized with a high content of phenolic compounds and the seed constitutes a high oil yield with beneficial effects on human health because of their antioxidant, antimicrobial, and anti-inflammatory properties. There has been a great interest in sour cherry by-products due to the increasing production rate of sour cherry worldwide and the increasing efforts on seeking bioactive compounds from natural sources as functional food. Thus, there have been a number of studies regarding the sour cherry pomace and sour cherry seed, especially in the last five years. The present review summarizes the chemical, biological, functional, and technological properties of the sour cherry pomace and sour cherry seed with their current and potential applications.     

Extrusion of poly(ether imide) foams using pressurized CO2: Effects of imposition of supercritical conditions and nanosilica modifiers

Foams of an engineering plastic, poly(ether imide), were extruded using a single screw extruder employing pressurized CO₂ as the blowing agent. The porosity, pore size distributions, and the density of the foams were especially affected by the pressure drop, the pressure loss rate, and temperature at the die. Significant increases in porosity and pore size and corresponding decreases in density were observed when the pressure imposed on CO₂ became greater than the critical pressure values of CO₂ (i.e., the temperature was always greater than the critical temperature of the CO₂ in the extruder and the die). The viscoelastic material functions of the extruded foams depended especially on the density of the foam, with the elastic modulus increasing with density. The incorporation of nanosilica particles in the 0.08–0.6% by weight range increased only the density of the foam and did not provide any benefits in controlling of the nucleation rate and the pore size distribution, presumably due to their poor dispersibility and agglomerated state in the single screw extruder. POLYM. ENG. SCI., 54:2064–2074, 2014. © 2013 Society of Plastics Engineers     

In vitro faecal fermentation outcomes and microbiota shifts of resistant starch spherulites

In the present study, we prepared A- and B-type polymorph-resistant starch spherulites (RSSs) with a wide range of crystallinity, and elucidated the relation between crystalline structure and faecal microbial fermentation outcomes. A- and B-type polymorphic RSSs displayed similar fermentation rate throughout entire process with final gas production of 11.8–13.2 mL, suggesting that the crystalline pattern and crystallinity cannot effectively control the fermentation rate of starches. The acetate and butyrate concentration of A-type RSS decreased with the increase of crystallinity respectively, and highly crystalline B-type RSS reduced the production of acetate (8.4 mM) and propionate (2.1 mM). RSSs with different crystalline types showed similar microbial community structure but distinct key bacteria species. A-type RSSs greatly promoted the abundance of butyrogenic bacteria (i.e., Roseburia faecis and Lachnospiraceae), whereas B-type RSSs tended to proliferate Prevotella copri associated with propionate production. Our findings shed new light on design and manufacture of starch-based functional ingredients with enhanced gut health.     

Effect of sourdough starter and fungal proteases on gluten content and sensory properties of tarhana

In this study, gluten degradation during prolonged tarhana fermentation was monitored in a traditional dough as well as in dough containing sourdough starter, peptidase additives and combination of both. Gluten content, determined using the sandwich ELISA assay method, was reduced significantly in the first 5 days of fermentation for all formulations. After 30 days into fermentation, approximately 15% and 20% reduction of gluten was observed in the traditional dough and sourdough starter added dough, respectively. In enzyme supplemented formulations, the mean gluten levels were below 20 ppm by 20 days of fermentation. Results showed that proteolytic enzyme addition to the dough mix can potentially render long fermented tarhana a food which conforms to regulations set forth for gluten-free foods, even though wheat flour is one of the main production ingredients. Sensory evaluation of the 30 day fermented tarhana samples revealed differences in sourness and odour properties of the products.     

Microbiological and chemical quality of different types of salted pearl mullet (Chalcalburnus tarichi Pallas, 1811)

This research aimed to determine microbiological and chemical quality of different types of salted pearl mullet (Chalcalburnus tarichi Pallas, 1811). Samples of salted pearl mullet (C. tarichi Pallas, 1811), produced by six different methods, were obtained from three different local producers at the end of the hunting season of 2016 and 2017 (May–June) with wooden boxes, plastic cans, or in bottom perforated plastic cans. Samples stored in a cold storage (2 ± 2°C) were analyzed in August and September of 2017. Six fish were used in each sampling day and thus the analyses were completed in 18 days. So, 108 fish samples were analyzed (3 producer × 6 method × 3 sample for each method × 2 hunting season). Analysis results were calculated as mean ± SD. One-way analysis of variance was used to determine whether there was a significant difference between the sample groups analyzed, and p < .05 was considered significant. All sample groups were found to be appropriate according to total mesophilic aerobic bacteria count, but one sample group (OS11-old sample, gutted and cleaned fish producted in wooden box according to method 1) included Salmonella spp. and Vibrio parahaemolyticus, it was found to be inappropriate (p < .05). The total volatile basic nitrogen acceptability upper limit (25–30 mg/100 g) were found to be exceeded in three sample groups (OS12-old sample, ungutted, and uncleaned fish producted in wooden box according to method 1, OS31-old sample, gutted, and cleaned fish producted in bottom perforated plastic can according to method 3, OS32-old sample, ungutted, and uncleaned fish producted in bottom perforated plastic can according to method 3) (p < .05) and the tiobarbituric acid index value was found to vary between 13.32 ± 0.08 and 31.43 ± 0.04 μg malondialdehyde/g (p < .05). According to histamine results, all sample groups were determined at acceptable values (p > .05). However, it was determined that the salt amount of the sample groups was very high in raw, and that more than half of the salt amount remained in the samples, even after baked waiting for 3 hr in warm water (p < .05).