Grant Murray Campbell

Arabinoxylans (AX) and their oligosaccharides (AXOS) have potential as functional ingredients. The emergence of biorefineries, leading to more Distillers Dried Grains with Solubles (DDGS) entering the animal feed market, encourages commercial production of AX products. Extracting AX from the two components of DDGS offers the opportunity to increase the biorefinery’s product portfolio and reduce costs. This paper explores AX extraction from solubles and wet grain, using a Gunt pilot-scale bioethanol plant to produce the two streams. After fermentation and distillation, solids were separated from the liquid to give Wet Distillers Grain (WDG), from which alkaline hydrogen peroxide extraction of water-unextractable AX (WUAX) was performed. The water-extractable AX (WEAX) was recovered from the solubles by ultrafiltration and ethanol precipitation. Both extracts were tested for suitability for AXOS production and characterised for their functionality. 10 kg of wheat yielded 3.2 litres of ethanol at 90% purity, 85 g of WUAX (51.6% purity, 110 kDa) and 92 g of WEAX (74.2% purity, 70 kDa). Enzymatic conversion of WEAX into oligosaccharides was 53%, whereas WUAX was unsusceptible to enzyme hydrolysis. Both AX fractions showed interactions with starch that could increase the shelf life of bakery products. AX-based products could be produced from a range of agricultural and biorefinery waste or low value streams, with the global market potentially > £1 billion per annum.

TheFrontiers in Chemical Engineering Educationinitiative in the USA in the early 2000s proposed a reformed chemical engineering curriculum organised around the three themes ofMolecular transformations,Multiscale analysisand aSystemsview. It was subsequently observed that few departments in the USA had adopted this structure for their programmes, although several UK programmes appeared already to feature this structure. Therefore, the objective of the current work was to analyse BEng chemical engineering programmes in the UK relative to this tripartite structure, in order to evaluate to what extent theFrontiersmodel was already represented within UK chemical engineering education. From the 28 UK universities offering IChemE-accredited programmes, the structure and content of 24 BEng programmes were analysed against the tripartiteFrontiersstructure. All 24 programmes broadly followed theFrontiersstructure. The greatest variation between programmes was in the amount of content contributing to theMolecular transformationstheme, which varied from 1.4 to 26%. This was also the smallest of the three themes, contributing on average around 10%, compared with 37% forMultiscale analysisand 38% forSystems, with 10% coming fromSupporting Competences(such as laboratory and professional skills) and 5% fromOthersubjects (such as mechanical or electrical engineering or electives).Molecular transformationswas generally most prominent in the first year, the second year tended to contribute the mostMultiscale analysiscontent and the final year was dominated bySystems. The Institution of Chemical Engineers’ Accreditation guidance tends to encourage the highSystemsemphasis and lowMolecular transformationscomponent, in contradiction to the recommendations of theFrontiersinitiative. Optional electives and MEng specialisms featureMolecular transformationsemphases, the latter less so than in the 2000s, since when the drivers for curriculum development have moved from biosciences and nanotechnology towards energy and sustainability.

The effects of sheeting on bread dough development and baked loaf quality were investigated, using Dynamic Dough Density and springback to quantify development, and examining effects of the sheeting regime on bread quality in terms of loaf volume and crumb structure. Bread doughs, with and without bran at different levels and particle sizes, were formed through a short mixing period, then sheeted through a benchtop manual sheeter at roll gaps of 6, 9 and 12 mm for different numbers of sheeting passes. The sheeting of doughs without bran increased dough expansion and baked loaf volume up to 12 sheeting passes. Loaves were larger after sheeting at a 6 mm roll gap, reflecting the greater gluten development at the smaller gap, although the crumb structure was less fine, with fewer gas cells and larger average gas cell diameters. The addition of bran decreased dough expansion and loaf volumes, with Fine bran and Coarse bran both more damaging than Medium bran, indicating the opportunity to optimise bran particle size to maximise bread quality. Sheeting was effective in alleviating the damaging effects of bran, with sheeting for 8 passes giving more dough expansion, larger loaf volumes and finer crumb structures than sheeting for 12 passes, indicating an even more damaging effect of bran when gluten is overstretched by sheeting. The work demonstrates the opportunity to enhance bread quality, particularly of healthy high-fibre breads, by employing sheeting to enhance gluten development and to offset the damage to gluten caused by the presence of bran.

BACKGROUND: Dehulling and splitting are important elements of the milling process to produce dhal from pulses. However, grain that is difficult‐to‐mill because of tightly adhered seed coats or cotyledons that resist separation makes it difficult to achieve high quality dhal. Milling yields are reduced, energy inputs into the milling process are increased, and the resulting dhal can be of poorer quality, chipped or abraded.RESULTS: Eight enzyme pre‐treatments were chosen based on the hypothesised mechanisms of seed coat and cotyledon adhesion established previously. Using a difficult‐to‐mill chickpea (Cicer arietinum L.) genotype, we examined the effects of these pre‐treatments, over time, on laboratory‐scale milling performance and dhal quality. We pioneered a texture analyser method to measure the flex of the cotyledons and the force required to cleave the cotyledons. The enzyme‐induced changes ranged from negative (tough seed coat, weight loss, deleterious colour and texture, increased visual damage to cotyledons and increased kibble loss, concave cotyledons, increased flex, and changes in taste) to positive (brittle seed coat, increased seed volume, improved dehulling efficiency and splitting yield, reduced cotyledon cleavage force, and acceptable dhal quality and taste).CONCLUSION: All pre‐treatments improved milling performance compared to milling the raw seed, although there was considerable variation between them. Two pre‐treatments showed no improvement in milling yields compared to the water control, and several pre‐treatments resulted in unacceptable qualities. Three pre‐treatments, endo‐polygalacturonanase, α‐galactosidase and cellulase, show potential for commercial milling applications and could assist pulse millers globally to achieve high quality dhal at the same time as minimising milling effort. © 2021 Society of Chemical Industry.