This is a review of mucus, and its principal component, mucins, in oral processing; it examines oral processing from the viewpoint of mucins being integral functional constituents of the food after the latter's insertion into the mouth. Under this light, mucins are treated as an omni-present functional ingredient. The chemical physics of the bolus formation is examined, focused on the role of mucins in the process. The colloidal and rheological aspects of hydrocolloids-mucin systems are subsequently examined, highlighting the role of the oral glycoproteins in complex food models and complex foods. Following the physicochemical and mechanical description of the topic, mucus is examined as a determinant of a food's sensory attributes. Its role in oral sensations such as astringency is reviewed, with a special focus on phenol-mucin interactions. The effect of mucus on the perception of saltiness is then reviewed, and the ensuing strategies for structurally-based reduction of salt are considered. The review critically discusses the challenges and opportunities that emerge from the above, highlighting the role of mucins and their effect on food function.

Polysaccharides extracted from fruits and leaves of baobab tree (Adansonia digitata) were assessed for their emulsifying capacity. Emulsions were formed at acidic pH (pH 2.0 and phi = 0.1) and were investigated by means of droplet size distribution analysis, zeta-potential measurements, and interfacial composition analysis. Despite the macromolecular differences of baobab polysaccharides all emulsions were formulated at concentrations resulting in comparable zero shear viscosity of the continuous phase allowing structure vs. function relationships to be made. Emulsions made with fruit polysaccharides formed finer droplets and exhibited good long term stability than those formulated with leaf polysaccharides. Stability was achieved by formation of thick interfacial layers, as evidenced by the large polysaccharide interfacial loading (Gamma(polysaccharide) 13.8 or 20.7 mg m(-2)) that created an effective steric barrier against droplet growth, whereas proteins did not seem to play central role. Fruit polysaccharide emulsification performance at acidic pH was attributed to their compact conformation at the interface that is linked to their structure. Conversely, the presence of rhamnogalacturonan segments in leaf polysaccharides resulted in chain desorption and poor emulsion stability. Overall, it has been shown that baobab fruit polysaccharides could be suitable emulsifiers for a range of technological applications that require low pH stability.

Linkage patterns and relaxation dynamics of baobab (Adansonia digitata) polysaccharides have been investigated by means of linkage analysis and rheometry. The fruit polysaccharide was mostly xylogalacturonan, with co-extracted α-glucan. The leaf polysaccharide consists predominantly of two domains, one branched at O-4 of the →2)-Rhap-(1→ residues and another branched at O-3 of the →4)-GalpA-(1→ backbone to single GlcpA-(1→ residues. Master curves of viscoelasticity of fruit polysaccharides manifested strong pH-dependency. At pH below the dissociation constant of galacturonic acid, dispersions showed liquid-like behaviour. In contrast, at neutral pH, a weak gel network formation was observed that destabilised rapidly under the influence of flow fields. The present work identifies xylogalacturonans from baobab fruit as polysaccharides with unique rheological characteristics that may point to new directions in food and pharmaceutical formulation.

This research studied the commercial exploitation of an indigenous African crop in order to formulate high value products, with a potential significant impact on the local economy. More specifically, the present work investigated the extraction of polysaccharides from baobab in a bench-scale unit, focusing on the overall yield and the techno-economic assessment of the extraction process. Preliminary technoeconomic analysis for two scenarios (with and without ethanol recycling) was performed to determine the economic viability of the process and the development of the baobab market both in Nigeria and the UK. A full economic analysis was undertaken for each of the two scenarios, considering all operating and capital costs, and the production cost of baobab polysaccharides was estimated based on a constant return on investment. Combining the operating cost with the average polysaccharide yield, the minimum profitable selling price in the UK was estimated to be between £23 and £35 per 100 g of polysaccharide, which is comparable to the commercial selling price of high purity polysaccharides. An assessment of a scaled-up plant was also performed under Nigerian conditions and the results showed that such an investment is potentially viable and profitable, with a minimum profitable selling price of £27 per 100 g, a value comparable to the UK-based scenarios.

Summary Soluble dietary fibres from sugarcane bagasse were extracted under alkaline conditions and characterised. Precipitated fibres were dialysed, and the fibre composition was evaluated before and after the dialysis step. Compositional analysis indicated that the fibres both before and after dialysis consisted of 39% w/w total sugars, 16% w/w protein, 10% w/w Klason lignin and 30% w/w ash. Xylose was the main neutral sugar followed by arabinose with glucose, galactose and uronic acids also present in all samples. The structural properties were also spectroscopically examined, which confirmed the presence of arabinoxylans. Macromolecular characterisation revealed that molecular weight is reduced after dialysis, indicating that a range of dietary fibres with different macromolecular characteristics may be obtained depending on the specific processing steps. The present work shows that soluble arabinoxylans may be obtained from sugarcane agricultural wastes that may be used as a source of novel dietary fibres.

BACKGROUND Pectin characteristics from different parts of lemon fruit (Citrus limon L.) were studied as a basis for assessing their suitability for functional applications. Pectin was extracted from lemon albedo, lemon core parts and membranes, and lemon extract using an aqueous extraction protocol. The composition and structural properties of the isolated pectins were examined by means of complementary analytical methods to assess their molecular characteristics for potential industrial applications. RESULTS The isolation protocol yielded pectins that were predominantly composed of galacturonic acid, with differences in the degree of methylation and neutral sugars content, and with low protein content, indicating high-purity materials. The same extraction protocol resulted in differences in yield and purity between the three different parts of lemon fruit, and in structural variations in the pectin backbone, as evidenced by differences in sugar composition and molecular weight. Solutions of the isolated lemon pectins exhibited pseudoplastic behavior. Macromolecular characterization showed that the lemon extract pectin had the highest molecular weight and hydrodynamic volume, followed by lemon core and lemon albedo pectin. CONCLUSION The work demonstrates that pectins with distinct structural properties may be extracted from different parts of lemon wastes and used for different technological purposes. (c) 2019 Society of Chemical Industry

Isolation steps of okra hydrocolloid and its thermodynamic parameters.

Objectives Evaluate the impact of salt and counterion identity on performance of solid immediate release dosage forms of miconazole and clopidogrel, respectively, in fasted upper gastrointestinal lumen using in-vitro methodologies.Methods Two miconazole chemical forms (free base and nitrate salt) and three clopidogrel chemical forms (bisulfate, besylate and hydrochloride salts) were studied. Solubilities of miconazole forms were measured in simulated gastric fluids. Gastrointestinal transfer of the five chemical forms was evaluated by using a flow-through, three-compartmental set-up. Precipitation in duodenal compartment was evaluated by using solutions in gastric compartment.Key findings Solubilities in simulated gastric fluids, concentrations in duodenal compartment and solubilities in duodenal compartment indicated poorer performance of miconazole nitrate vs. miconazole free base in upper gastrointestinal lumen. In line with the low crystallization tendency of free base, duodenal precipitation of miconazole from a free base solution was limited. Concentrations in duodenal compartment indicated that counterion identity does not affect the performance of clopidogrel; precipitation in duodenal compartment was extensive in all cases.Conclusions Miconazole data indicate that salts may adversely affect performance of immediate release dosage forms of weak bases. In line with existing in-vivo data, clopidogrel data indicate that counterion identity is unimportant for the performance of clopidogrel salts in upper intestinal lumen.

The self-assembly of a macromolecular population of interest in food, cosmetics, and pharmaceutics, namely okra polysaccharide mucilage, has been studied by means of micro-differential scanning calorimetry (μ-DSC), static light scattering, and intrinsic viscosity measurements. The experiments, held in water–dimethylsulfoxide (DMSO) mixtures, and based on successive dilutions of DMSO solutions with water and vice versa, suggest the existence of history-dependent pseudo-equilibrium states, in structures where the other components of the hydrocolloid mucilage, namely proteins, should be actively partaking. A hexamer supermolecular structure, comprising of smaller supermacromolecular entities held together by hydrogen bonding, is proposed as a typical structure of okra mucilage in aqueous systems.

An insight into adsorption thermodynamics of molecular probes onto the mucin surface of porcine intestinal is given by the aid of IGC based on chromatographic retention time.

Maillard conjugates have been prepared in situ in okra mucilage from the existing populations of protein and polysaccharide. SEC MALLS/UV and FTIR data suggest that an initial ensemble of polysaccharide and protein changes dramatically during heating at 100 degrees C for 6 h. While the raw extracts and the products of milder heat treatments are inefficient emulsifiers at neutral pH, the conjugates prepared from the above heat treatment are efficient emulsifiers for n-hexadecane-in-water emulsions, both in terms of initial average droplet size (d(32)) and the evolution of d(32) and d(43) over a week's stay at ambient conditions. The emulsifying ability of these products is superior to that of the more conventional Maillard products of the reaction between bovine serum albumin (BSA) and okra extract (experiments held in parallel). The emulsifying ability of the above materials is in complete agreement with the relevant measurements of the development of their interfacial tensions. The above suggest that the intrinsic components of natural extracts can lead to Maillard products of commercial interest, and form a solid basis for the possible exploitation of okra as an emulsifier, rather as a thickening agent. (C) 2015 Elsevier Ltd. All rights reserved.

An extensive surface characterization of okra hydrocolloid extract was conducted by means of inverse gas chromatography (IGC) at infinite dilution in three temperatures (40, 50, 60 degrees C). The specific retention volume of 14 solvents, used as probes, was utilized for the assessment of the surface energy, the free energy of adsorption, as well as the relevant enthalpy and entropic component. The contribution to the surface energy of okra extract decreases with increasing temperature. Furthermore, surface characterization demonstrated that the okra extract matrix is Lewis amphoteric with predominantly basic character, as confirmed by the acidity and basicity constants K-A and K-B, respectively. The above were discussed in conjunction with X-ray diffractometry (XRD), size exclusion chromatography (SEC-MALLS/UV), and Fourier transform infra-red spectroscopy (FTIR) data. (C) 2014 Elsevier B.V. All rights reserved.

Novel composite materials comprising of okra hydrocolloids and hydroxyapatite of potential interest for the field of bone engineering have been prepared using various ratios of the above substances. The resulting materials were characterized using X-ray diffractometry (XRD), Fourier transform infra-red spectroscopy (FTIR), and thermogravimetric analysis (TGA). The topological distribution between organic and inorganic components has been studied using scanning electron spectroscopy coupled with energy dispersive spectroscopy (SEM–EDS) and micro-FTIR. Scanning electron microscopy (SEM) examination suggests microporous samples, while emulsion templating shows potential of further increasing the porosity of the samples containing lower ratios of okra extract to hydroxyapatite. The above pinpoint to the potential of okra hydrocolloids to form a putative basis for the development of prosthetics and scaffolds for bone and cartilage engineering.