Effect of moisture content on thermal and water absorption properties of microfibrillar cellulose with polymeric additives

The aim of this study was 1) to investigate the influence of polymeric additives such as carboxyl methyl cellulose (CMC) and locust bean gum (LBG) added before and after homogenisation on the moisture uptake of microfibrillar cellulose (MFC) in the dry and semi-wet state; and 2) to further understand the thermally induced structural transitions of low moisture MFC in the presence of the polymeric additives. A higher moisture content in the highly dense MFC network maintains the fibrillated network structure, which is lost during the drying process resulting in MFC aggregates. The addition of polymeric additives results in the regaining of the structure upon redispersion of the dry material with CMC being more effective than LBG). Results also indicated that CMC has a high level of compatibility with MFC, whereas LBG appears to have limited distribution in the MFC dense microfibrillar network and probably exists as a separate phase when added after homogenisation, however co-processing of LBG and cellulose significantly changed this behaviour. The presence of low-temperature transitions in MFC/additives/water mixtures indicates the involvement of these semi-flexible polymeric additives in the formation of liquid crystals when added to MFC in low moisture environments (2% and 20% w/w). An insight is offered into the theory of surface interactions between MFC and polymeric additives, which prevents the agglomeration of microfibrils present in the highly fibrillated suspension upon drying

Stabilisation of oil-in-water emulsions with non-chemical modified gelatinised starch

In this research, stabilisation of oil-in-water emulsions with non-chemically modified gelatinised starch is presented. Thus far only octenyl succinic anhydride(OSA) modified gelatinised starch has been known to adsorb at emulsion droplet interfaces, acting as emulsifiers. Screening a range of commercially available food starches revealed that a non-waxy rice starch, a waxy rice starch and the waxy maize starch PRIMA600 showed oil-in-water emulsifying ability following gelatinisation. The microstructure of emulsions formulated with 20 % oil and 1 % starch was stable for at least 3 months. Thermal, crystallinity and molecular property analyses as well as amylose and protein content revealed no obvious link to this property. Nevertheless, this research has provided the food industry with exciting results for the formulation of clean label emulsions. Moreover, it presents a concept for oral release food emulsions with destabilisation via salivary amylase digestion of the stabilising starch emulsifier

Stabilisation of oil-in-water emulsions with non-chemical modified gelatinised starch

In this research, stabilisation of oil-in-water emulsions with non-chemically modified gelatinised starch is presented. Thus far only octenyl succinic anhydride(OSA) modified gelatinised starch has been known to adsorb at emulsion droplet interfaces, acting as emulsifiers. Screening a range of commercially available food starches revealed that a non-waxy rice starch, a waxy rice starch and the waxy maize starch PRIMA600 showed oil-in-water emulsifying ability following gelatinisation. The microstructure of emulsions formulated with 20 % oil and 1 % starch was stable for at least 3 months. Thermal, crystallinity and molecular property analyses as well as amylose and protein content revealed no obvious link to this property. Nevertheless, this research has provided the food industry with exciting results for the formulation of clean label emulsions. Moreover, it presents a concept for oral release food emulsions with destabilisation via salivary amylase digestion of the stabilising starch emulsifier

Freshwater and airborne textile fibre populations are dominated by ‘natural’, not microplastic, fibres

The potential role of natural textile fibres as environmental pollutants has been speculated upon by some environmental scientists, however, there is a general consensus that their biodegradability reduces their environmental threat. Whilst the risks that they pose remain poorly understood, their environmental prevalence has been noted in several recent microplastic pollution manuscripts. Here we highlight the extent to which natural textile fibres dominate fibre populations of upstream reaches of the River Trent, UK, as well as the atmospheric deposition within its catchment, over a twelve month microplastic sampling campaign. Across 223 samples, natural textile fibres represented 93.8% of the textile fibre population quantified. Moreover, though microplastic particles including synthetic fibres are known to be pervasive environmental pollutants, extruded textile fibres were absent from 82.8% of samples. Natural textile fibres were absent from just 9.7% of samples

Compositional and physicochemical factors governing the viability of Lactobacillus rhamnosus GG embedded in starch-protein based edible films

Probiotic incorporation in edible films and coatings has been shown recently to be an efficient strategy for the delivery of probiotics in foods. In the present work, the impact of the compositional, physicochemical and structural properties of binary starch-protein edible films on Lactobacillus rhamnosus GG viability and stability was evaluated. Native rice and corn starch, as well as bovine skin gelatine, sodium caseinate and soy protein concentrate were used for the fabrication of the probiotic edible films. Starch and protein type both impacted the structural, mechanical, optical and thermal properties of the films, and the process loss of L. rhamnosus GG during evaporation-dehydration was significantly lower in the presence of proteins (0.91 to 1.07 log CFU/g) compared to solely starch based systems (1.71 log CFU/g). A synergistic action between rice starch and proteins was detected when monitoring the viability of L. rhamnosus GG over four weeks at fridge and room temperature conditions. In particular, a 3- to 7-fold increase in the viability of L. rhamnosus GG was observed in the presence of proteins, with sodium caseinate – rice starch based films offering the most enhanced stability. The film’s shelf-life (as calculated using the FAO/WHO (2011) basis of 6 log viable CFU/g) ranged between 27-96 and 15-24 days for systems stored at fridge or room temperature conditions respectively

New insights into xanthan synergistic interactions with konjacglucomannan: a novel interaction mechanism proposal

The interactions of xanthans containing precise acetate and pyruvate concentration with Konjac gluco-mannan (KGM) were studied at different sodium chloride and polymer concentrations. A new unifiedmodel of the interaction is proposed, taking into account previous models in the literature. This study sug-gests that the interactions occur by two distinct mechanisms dependent on xanthan conformation. These interactions are not mutually exclusive and may co-exist and hence produce complicated traces. Consequently two types of gel which melt at different temperature ranges can be formed. Depending on the xanthan helix coil transition temperature, one or both of the synergistic states may exist in the hydrocolloid blend. The proposed model has been tested rheologically and using differential scanning calorimetry by varying salt concentration and using samples containing different functional group concentrations

The state of water and fat during the maturation of Cheddar cheese

Cheddar cheese predicted to develop into different quality classes has been evaluated by time domain Nuclear Magnetic Resonance, Thermogravimetric analysis and quantitative sensory analysis. The water and fat proton signals in the transverse relaxation decay curves have been deconvoluted. Proton transverse relaxation values for both the water and fat fractions decrease and the relative %age of the proton peak area, predominantly from the fat increases over a 450-day ripening period. The thermodynamic free water percentage increases during maturation. Water and fat attributes can distinguish between Cheddar cheese batches after 56 days. Cheese batches which have lower transverse relaxation values for the water and fat proton fractions and a higher relative %age of the proton peak area predominantly from fat at 56 days, mature after 270 days to be more yellow, rubbery and smooth, have a less sour and lingering aftertaste and are also harder to form into a cheese ball

Effect of granule organisation on the behaviour of starches in the NMMO (N-methyl morpholine N-oxide) solvent system

The response of starches of different botanical origin to heating in 78% N-methyl morpholine N-oxide (NMMO) is compared with their behaviour in water. For all starches studied an exothermic transition is obtained in the NMMO system rather than the endothermic transition in water. In NMMO the transition temperatures are lower for A-type starches (wheat, rice and tapioca) than the C-type starches (sago and pea) and also potato which has a B-type polymorph. Observations using a hot stage microscope show two different types of initial behaviour in NMMO; erosion of the granule from the surface or disruption into fragments. In both cases the final outcome is dissolution but for the most resistant C-type starches (pea and sago) some intact granules could be seen following heating at 95 °C in 78% NMMO and subsequent precipitation in ethanol. The results are discussed in terms of what is known from previous structural studies on these six starches and the behaviour of maize starch in NMMO and ionic liquids. The work is relevant to the co-dissolution of starch and cellulose to form novel polysaccharide based materials

Freshwater microplastic concentrations vary through both space and time

Plastic pollution represents one of the most salient indicators of society’s impact on the environment. The microplastic component of this is ubiquitous, however, microplastic studies are seldom representative of the locations they sample. Over 12 months we explored spatiotemporal variation in microplastic prevalence across a freshwater system and in atmospheric deposition within its catchment, in one of the most temporally comprehensive studies of microplastic pollution. Microplastics were quantified in low concentrations (max 0.4 particles L-1) at all freshwater sites, including upstream of urban areas, and on rivers that do not receive wastewater treatment plant effluent. Extrapolated microplastic abundances at each site varied by up to 8 orders of magnitude over the course of the sampling campaign, suggesting that microplastic surveys that do not account for temporal variability misrepresent microplastic prevalence. Whilst we do not wish to underplay the potential impacts of microplastic particles in the environment, we argue that microplastic pollution needs to be placed in a more critical context, including assessment of temporal variability, to appropriately inform legislators and consumers