Bilberries represent a valuable northern European wild berry crop, well regarded for their high content of bioactive compounds and perceived health benefits. In Sweden, other than consumption of fresh whole berries, processing into juice is the most common route. To optimise the extraction of juice from bilberries and to investigate the impact on juice quality, fresh berries were pre treated using a range of techniques prior to pressing. Blanching the berries or treating them with pectinase enzymes gave the highest juice yield with 74 and 83% recovery (%, w/w), respectively (approx. 3.4 to 3.8 times the control). Freezing the berries prior to pressing was as effective as grinding + heating and resulted in a 2.8 fold increase in yield. Use of a screw press instead of a hydraulic press increased the yield 3.4 fold with no other pre treatment. Freezing prior to screw press only resulted in a modest increase in yield from 75 to 78% when using t he screw press. but was still an improvement versus freezing prior to hydraulic press. In terms of the quality of the juices, blanching, grinding and heating, and pectinase treatment had the highest phenolic content, but pectinase treatment resulted in the highest overall extraction yield from the berries. Again screw press increased the con tent of phenolic compounds in the juice and had higher extractive yields from the berries. The antioxidant content of juices (measured as ferric reducing antioxidant potential) followed the same trend as the phenolic content. Overall, use of a screw press increased the juice yield versus a hydraulic press, but the use of pectinase enzymes still appears to be the most effective treatment for maximising the juice yield when using the hydraulic press. Freezing and blanching berrie s prior to processing has a positive impact on juice yield, phenolic content, and antioxidant capacity, especially for hydraulic pressing. The use of pectinase enzymes increased the extractive yields of juice and phenolic compounds extracted from the berri es, but the composition of the juices themselves were very similar when blanching, freezing, or grinding and heating were used, suggesting the use of expensive enzymes may not be necessary to produce juices rich in antioxidant compounds on a cost benefit l evel. Future work should investigate the combination of enzyme treatment followed by screw press as well as the cost and life cycle implications of the different processing conditions.

lant proteins such as soy, pea and wheat gluten are known to form a fibrous structures resembling chicken meat when extruded at elevated temperature with subsequent active cooling. The current hypothesis on the mechanisms responsible for the fibre formation contribute to understanding but are not sufficient to describe the full picture and cannot be used to predict fibre formation ability of protein melts thus hampering the use of more sustainable protein ... interactions between protein chains or polymer crystallites. The aim of the present study to use rheological data of protein melts combined with simulation to elucidate the fibre formation mechanisms and this paper will show an example.

Whole grain flours contain polysaccharides with techno-functional and nutritional properties which make them good candidates as natural texturisers in foods and beverages, thus reducing the use of highly refined ingredients. However, the use of plant components to develop complex fluids and soft materials, requires an enhanced understanding of the relationship between their physicochemical and rheological properties. Here, we systematically investigated the shear and extensional rheological properties of aqueous suspensions of whole grain rye and oat flours. Our results indicated that both types of suspensions (3.5 wt %) showed similar shear thinning behaviour (n = 0.4) however, oat suspensions presented higher viscosity and gel-like behaviour (G'>G'') compared to rye. Additionally, the oat suspensions exhibited an apparent extensional viscosity, which was not present in rye suspensions. The rheological properties of the continuous and disperse phases, separated by centrifugation, were investigated before and after starch hydrolysis and protein removal. Our results indicate that the distinct behaviour of oat suspensions is mainly due to the molecular structure of starch in the liquid phase of i.e oat starch had a higher amylose/amylopectin ratio than rye. Whilst the presence of protein and cell wall polysaccharides in the solid phase contribute to the overall rheology of the suspensions. Furthermore, our results show that the systems do not follow the Cox-Merz rule, indicating that they behaved as suspensions of soft particles rather than macromolecules in solution. Aqueous suspensions of whole grain rye and oat flours showed rheological properties that could be of interest to design low-medium viscosity food and beverage products. © 2022 The Authors