Flavonoids, sugars and fruit acids of alpine bearberry (Arctostaphylos alpina) from Finnish Lapland

Alpine bearberry (Arctostaphylos alpina L.) is a special circumpolar edible berry primarily used for household purposes but with greater potential in commercial applications than utilized thus far. In this study, the flavonoids of alpine bearberry were investigated with HPLC-DAD and HPLC-MS, and the sugars and fruit acids as trimethylsilyl derivates with GC-FID. The most abundant anthocyanin was cyanidin-3-O-galactoside accounting for over 95% of the anthocyanins. Eight other anthocyanins existed in trace amounts only, the richest of them being cyanidin-3-O-arabinoside and cyanidin-3-O-glucoside. Cyanidin accounted for over 99% of the anthocyanin aglycones. All the flavonols identified were glycosides of quercetin. Majority of the sugars were glucose and fructose while the most abundant fruit acid was quinic acid. The unique anthocyanin composition of alpine bearberry encourages advanced use of the berry as a food ingredient in private households and in industrial applications. In addition, it serves as a unique reference material for research purposes.     

Structural mechanisms leading to improved water retention in acid milk gels by use of transglutaminase

Water retention in transglutaminase (TG)-treated acid milk gels was studied and linked with the gel formation dynamics. Heat-treated skim milk with and without pre-treatment by TG was acidified at 20 °C, 30 °C and 40 °C at constant glucono-δ-lactone (GDL) level to obtain different acidification rates. Formation dynamics and structural properties of acid-induced gels were followed by rheological and near-infrared light backscattering measurements as well as microscopy. TG-treated gels showed decreased tan δ values all through the acidification, which was pronounced around the gelation point. Backscattered light intensity was lowered in TG-treated gels compared to the controls indicating that TG-treated gels were comprised of smaller aggregates. Water holding capacity (WHC) was measured by using centrifugation at selected pH points (pH 5.2, 5.0, 4.8 and 4.6) during acidification. Both acidification temperature and TG treatment had significant effects on the water retention properties of the gels. Spontaneous syneresis observed at high acidification temperatures (≥30 °C) was prevented upon TG-treatment. WHC of TG-treated gels was significantly higher compared to the control gels at all pH points. TG-treated milk gels showed a homogeneous network formed of smaller aggregate and pore sizes at the gelation point and did not show any large-scale re-organisation thereafter. Transglutaminase is likely to act as a fixative of the protein network at an early stage of gelation and thereby limiting network rearrangements that take place in acid milk gels formed at high acidification temperatures leading to contraction and subsequent wheying off.     

The sensory characteristics and rheological properties of soups containing oat and barley β-glucan before and after freezing

The aim was to study the effect of concentration and molecular weight of two oat and one barley β-glucan preparation on the perceived sensory quality of a ready-to-eat soup prototype before and after freezing. Oat1 was a bran-type preparation containing high molecular weight β-glucan; Oat2 and Barley were more processed and purified preparations with lower molecular weight. Nine soups containing 0.25-2.0 g β-glucan/100 g soup and one reference soup thickened with starch were profiled by a sensory panel and their viscosity and molecular weight of β-glucan was analysed.Freezing had no notable effects on the sensory quality of the soups. At the same concentration, soups made with the bran-type preparation were more viscous and had higher perceived thickness than soups made with processed, low molecular weight preparations. Barley soups had mainly higher flavour intensities than oat soups. Good correlations were obtained between sensory texture attributes and viscosity (r=0.70-0.84; P?0.001) and moderate correlations between flavour attributes and viscosity (r=−0.63-−0.80; P?0.001). Technologically, β-glucans are feasible thickening agent alternatives in soups. Preparations with lower molecular weight and viscosity are easier to add into a food product in higher quantities, but the role of high molecular weight β-glucan in physiological functionality has to be kept in mind.     

Effect of Oat Bran Fractions on Extrudates Made of Defatted Oats

Food and Bioprocess Technology - Oats are rich in dietary fibre (DF) especially in β-glucan which has several health-promoting effects. Oats are not commonly used in extruded snacks because...     

A survey on handling computationally expensive multiobjective optimization problems using surrogates: non-nature inspired methods

Computationally expensive multiobjective optimization problems arise, e.g. in many engineering applications, where several conflicting objectives are to be optimized simultaneously while satisfying constraints. In many cases, the lack of explicit mathematical formulas of the objectives and constraints may necessitate conducting computationally expensive and time-consuming experiments and/or simulations. As another challenge, these problems may have either convex or nonconvex or even disconnected Pareto frontier consisting of Pareto optimal solutions. Because of the existence of many such solutions, typically, a decision maker is required to select the most preferred one. In order to deal with the high computational cost, surrogate-based methods are commonly used in the literature. This paper surveys surrogate-based methods proposed in the literature, where the methods are independent of the underlying optimization algorithm and mitigate the computational burden to capture different types of Pareto frontiers. The methods considered are classified, discussed and then compared. These methods are divided into two frameworks: the sequential and the adaptive frameworks. Based on the comparison, we recommend the adaptive framework to tackle the aforementioned challenges.     

Designing Paper Machine Headbox Using GA

A non-smooth biobjective optimization problem for designing the shape of a slice channel in a paper machine headbox is described. The conflicting goals defining the optimization problem are the ones determining important quality properties of produced paper: 1) basis weight should be even and 2) the wood fibers of paper should mainly be oriented to the machine direction across the width of the whole paper machine. The novelty of the considered approach is that maximum deviations are used instead of least squares when objective functions are formed. For the solution of this problem, a multiobjective genetic algorithm based on nondominated sorting is considered. The numerical results demonstrate the ability to obtain a large set of nondominated designs.     

Flexographically printed fluidic structures in paper

This Technical Note demonstrates a simple method based on flexographic printing of polystyrene to form liquid guiding boundaries and layers on paper substrates. The method allows formation of hydrophobic barrier structures that partially or completely penetrate through the substrate. This unique property enables one to form very thin fluidic channels on paper, leading to reduced sample volumes required in point-of-care diagnostic devices. The described method is compatible with roll-to-roll flexography units found in many printing houses, making it an ideal method for large-scale production of paper-based fluidic structures.     

A new hybrid mutation operator for multiobjective optimization with differential evolution

Differential evolution has become one of the most widely used evolutionary algorithms in multiobjective optimization. Its linear mutation operator is a simple and powerful mechanism to generate trial vectors. However, the performance of the mutation operator can be improved by including a nonlinear part. In this paper, we propose a new hybrid mutation operator consisting of a polynomial-based operator with nonlinear curve tracking capabilities and the differential evolution’s original mutation operator, for the efficient handling of various interdependencies between decision variables. The resulting hybrid operator is straightforward to implement and can be used within most evolutionary algorithms. Particularly, it can be used as a replacement in all algorithms utilizing the original mutation operator of differential evolution. We demonstrate how the new hybrid operator can be used by incorporating it into MOEA/D, a winning evolutionary multiobjective algorithm in a recent competition. The usefulness of the hybrid operator is demonstrated with extensive numerical experiments showing improvements in performance compared with the previous state of the art.     

Chemical modification of cotton to improve fibre dyeability

A new fibre-reactive quaternary compound containing an acrylamide residue was synthesised and used as a cotton modification reagent. The agent was applied to cotton fabrics using a pad-bake process. It was found that the treated fibre could be dyed with reactive dyes without the addition of salt or alkali. The reactive dyes were almost completely exhausted and showed a high degree of covalent bonding with the pretreated cellulose. The effect of varying the pretreatment conditions was investigated and the optimum conditions for pretreating and dyeing were established.