Swiss cohort on Traumatic Childbirth and Health (SwiTCH): protocol for a prospective, population-based cohort study on parents' mental health from pregnancy to one year postpartum.

INTRODUCTION: Approximately 4%-5% of mothers develop childbirth-related post-traumatic stress disorder (CB-PTSD) and approximately 12.3% of mothers develop some CB-PTSD symptoms (CB-PTSS). To date, there is a dearth of studies on fathers and other coparents. Parental CB-PTSD and CB-PTSS may have a negative impact not only on the parents but also on the infant. Understanding risk and protective factors of CB-PTSD for both parents and its consequences on the family is key to detecting or anticipating it, to developing interventions aimed at reducing its detrimental effects and to supporting parents. METHODS AND ANALYSIS: This study protocol describes an observational, population-based study, consisting of a longitudinal prospective cohort with online surveys at four time points. The population of interest consist of women, in the third trimester of pregnancy or at 6-12 weeks postpartum, and their partner/coparent, who will give birth or gave birth in the French-speaking part of Switzerland. The target sample size is 300-500 women and a proportional number of partners. The primary outcome of this study is the prevalence of CB-PTSD and CB-PTSS. The secondary outcomes focus on: (1) the impact of CB-PTSD and CB-PTSS on the marital and coparental relationships, the bonding with the infant, parental burnout and healthcare seeking behaviours, (2) the role of the childbirth experience in the development of CB-PTSD and CB-PTSS and (3) the social and economic determinants of CB-PTSD and CB-PTSS. ETHICS AND DISSEMINATION: Ethical approval was granted by the human research ethics committee of the Canton de Vaud (study number 2022-00284). All study participants signed an informed consent form. Dissemination of results will occur via national and international conferences, in peer-reviewed journals, public conferences and social media. TRIAL REGISTRATION NUMBER: NCT05865704.

Changing Wheat Bran Structural Properties by Extrusion-Cooking on a Pilot and Industrial Scale: A Comparative Study.

Extrusion-cooking can be used to change the techno-functional and nutrition-related properties of wheat bran. In this study, pilot-scale (BC21) and industrial-scale (BC45) twin-screw extrusion-cooking using different types of extrusion (single-pass, double-pass and acid extrusion-cooking) and process parameters (temperature, moisture) were compared for their impact on wheat bran. When applying the same process settings, the higher strong water-binding capacity, extract viscosity and extractability displayed by bran extruded using the industrial set-up reflected a more considerable wheat bran structure degradation compared to pilot-scale extrusion-cooking. This was attributed to the overall higher specific mechanical energy (SME), pressure and product temperature that were reached inside the industrial extruder. When changing the type of extrusion-cooking from single-pass to double-pass and acid extrusion-cooking, wheat bran physicochemical characteristics evolved in the same direction, irrespective of extruder scale. The differences in bran characteristics were, however, smaller on industrial-scale. Results show that the differentiating power of the latter can be increased by decreasing the moisture content and increasing product temperature, beyond what is possible in the pilot-scale extruder. This was confirmed by using a BC72 industrial-scale extruder at low moisture content. In conclusion, the extruder scale mainly determines the SME that can be reached and determines the potential to modify wheat bran.

Extrusion-Cooking Modifies Physicochemical and Nutrition-Related Properties of Wheat Bran.

The potential of extrusion-cooking to change the physicochemical characteristics of wheat bran, increase its nutritional value and decrease its recalcitrance towards fermentation was investigated in this study. The conditions in a twin-screw extruder were varied by changing screw configuration, moisture content and barrel temperature. The former was not previously investigated in studies on bran extrusion. Extrusion-cooking resulted in an increased water-holding capacity and extract viscosity of bran, suggesting shear-induced structure degradation and structure loosening due to steam explosion at the extruder outlet. Modelling showed that the extent of these modifications mainly correlates with the amount of specific mechanical energy (SME) input, which increases with an increasing number of work sections in the screw configuration and a decreasing moisture content and barrel temperature. Extrusion led to solubilisation of arabinoxylan and ferulic acid. Moreover, it led to starch melting and phytate degradation. Upon fermentation of the most modified sample using a human faecal inoculum, small numeric pH decreases and short-chain fatty acid production increases were observed compared to the control bran, while protein fermentation was decreased. Overall, extrusion-cooking can improve the nutrition-related properties of wheat bran, making it an interesting technique for the modification of bran before further use or consumption as an extruded end product.

Flow and foam properties of extruded maize flour and its biopolymer blends expanded by microwave.

Maize flour and blends from starch and zein biopolymers were processed as dense materials by extrusion (120°C, 300J·g-1) and press-molding (140°C, 10min) at a constant moisture content (26%wb), and then foamed by microwave heating. The mechanical properties of foams, determined by a 3-point bending test, were governed by density, in agreement with an open solid foam model. The density and 3D cellular structure of the foams were determined by X-ray tomography. In the same interval of density [0.15, 0.3g·cm-3], foams from microwaved materials had a finer cellular structure than directly expanded materials at extruder outlet. The study of melt rheological behavior with Rheoplast® (100-160°C, SME≤200J·g-1) showed that protein content (0-15%) did not affect shear viscosity but increased elongational viscosity. This trend, similar to the one reported for the storage modulus in a rubbery state, could be attributed to dissipative effects in a starch/protein interphase, explaining the difference of expansion between starch, blends and flour.

Starch-based extruded cereals enriched in fibers: a behavior of composite solid foams.

Extruded cereals mainly composed of starch and enriched in fibers were produced with two types of base recipes: (i) one recipe mainly composed of wheat flour and (ii) one recipe mainly composed of corn and soya flours. The addition of fibers was performed through the use of oat bran concentrate or wheat bran, up to 32% of the recipe. The structure of the extrudates, assessed by X-ray tomography, pointed out the decrease of porosity and of mean cells size with the increase of the total dietary fibers content of the recipe. The hardness of the products, i.e. the maximum stress determined by a compression test, was linked to their porosity. The Gibson-Ashby relationship could be applied and the fit was even improved when considering the walls of the solid foam as composite materials. Fibers and proteins can be indeed considered as particles dispersed in the starchy phase. This work thus shows the impact of the structure of the extrudates on their mechanical properties. The structure is taken into account at different length scales; at the level of the porous structure and at the level of the phase of the main biopolymers present in the recipe (starch, proteins and fibers). The mechanical behavior of these products is then discussed according to their characteristics of composite solid foams.

Processing of novel elevated amylose wheats: functional properties and starch digestibility of extruded products.

Different types of novel wheat lines with different starch contents and amylose/amylopectin ratios, relating to defined alterations in the number and activity of starch synthase IIa genes, were processed by pilot-plant extrusion. Two types of products were produced: pure wholemeal products and breakfast cereals made from wholemeal/maize blends. Lower apparent shear viscosity was obtained in the extruder with lower starch content and higher amylose/amylopectin ratio flours (SSIIa-deficient line). The bulk density of the products decreased with increasing extrusion temperature and was always higher for the triple-null line. The bulk density was not completely explained by the melt shear viscosity, suggesting the importance of the fillers (fibers, brans) in the process of expansion and structure acquisition. The different mechanical properties were explained by the density and by the material constituting the cell walls. Enzyme-resistant starch (RS) content and hydrolysis index (HI) were not correlated to the extrusion temperature, but RS was higher in pure wholemeal products and in the SSIIa-deficient line. These results are discussed in terms of starch molecular architecture and product microstructure.

Influence of storage conditions on the structure, thermal behavior, and formation of enzyme-resistant starch in extruded starches.

Starch structures from an extrusion process were stored at different temperatures to allow for molecular rearrangement (retrogradation); their thermal characteristics (DSC) and resistance to amylase digestion were measured and compared. The structure of four native and processed starches containing different amylose/amylopectin compositions (3.5, 30.8, 32, and 80% amylose content, respectively) before and after digestion was studied with small-angle X-ray scattering (SAXS) and X-ray diffraction (XRD). Rearrangement of the amylose molecules was observed for each storage condition as measured by the DSC endotherm at around 145 degrees C. The crystalline organization of the starches after processing and storage was qualitatively different to that of the native starches. However, there was no direct correlation between the initial crystallinity and the amount of enzyme-resistant starch (ERS) measured after in vitro digestion, and only in the case of high-amylose starch did the postprocess conditioning used lead to a small increase in the amount of starch remaining after the enzymatic treatment. From the results obtained, it can be concluded that retrograded amylose is not directly correlated with ERS and alternative mechanisms must be responsible for ERS formation.

Effects of starch synthase IIa gene dosage on grain, protein and starch in endosperm of wheat.

Starch synthases (SS) are responsible for elongating the alpha-1,4 glucan chains of starch. A doubled haploid population was generated by crossing a line of wheat, which lacks functional ssIIa genes on each genome (abd), and an Australian wheat cultivar, Sunco, with wild type ssIIa alleles on each genome (ABD). Evidence has been presented previously indicating that the SGP-1 (starch granule protein-1) proteins present in the starch granule in wheat are products of the ssIIa genes. Analysis of 100 progeny lines demonstrated co-segregation of the ssIIa alleles from the three genomes with the SGP-1 proteins, providing further evidence that the SGP-1 proteins are the products of the ssIIa genes. From the progeny lines, 40 doubled haploid lines representing the eight possible genotypes for SSIIa (ABD, aBD, AbD, ABd, abD, aBd, Abd, abd) were characterized for their grain weight, protein content, total starch content and starch properties. For some properties (chain length distribution, pasting properties, swelling power, and gelatinization properties), a progressive change was observed across the four classes of genotypes (wild type, single nulls, double nulls and triple nulls). However, for other grain properties (seed weight and protein content) and starch properties (total starch content, granule morphology and crystallinity, granule size distribution, amylose content, amylose-lipid dissociation properties), a statistically significant change only occurred for the triple nulls, indicating that all three genes had to be missing or inactive for a change to occur. These results illustrate the importance of SSIIa in controlling grain and starch properties and the importance of amylopectin fine structure in controlling starch granule properties in wheat.