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To explain the cholesterol-reducing effects of dietary fibres, one of the major mechanisms proposed is the reduced reabsorption of bile acids in the ileum. The interaction of dietary fibres with bile acids is associated with their viscous or adsorptive effects. Since these fibre characteristics are difficult to investigate in vivo, suitable in vitro methodologies can contribute to understanding the mechanistic principles. We compared the commonly used centrifugal approach with a modified dialysis method using dietary fibre-rich materials from different sources (i.e., barley, citrus, lupin, and potato). Digestion was simulated in vitro with oral, gastric, and small intestinal digestion environments. The chyme was dialysed and released bile acids were analysed by high-performance liquid chromatography. The centrifugation method showed adsorptive effects only for cholestyramine (reference material) and a high-fibre barley product (1.4 µmol taurocholic acid/100 mg dry matter). Alternatively, the dialysis approach showed higher values of bile acid adsorption (2.3 µmol taurocholic acid/100 mg dry matter) for the high-fibre barley product. This indicated an underestimated adsorption when using the centrifugation method. The results also confirmed that the dialysis method can be used to understand the influence of viscosity on bile acid release. This may be due to entrapment of bile acids in the viscous chyme matrix. Further studies on fibre structure and mechanisms responsible for viscous effects are required to understand the formation of entangled networks responsible for the entrapment of the bile acids.

Activity-guided fractionations, combined with taste dilution analyses (TDA), were performed to locate the key compounds contributing to the bitter off-taste of pea-protein isolates (Pisum sativum L.). Purification of the compounds perceived with the highest sensory impact, followed by 1D/2D-NMR, (LC-)­MS/MS, LC-TOF-MS, and MSE experiments, led to the identification of 14 lipids and lipid oxidation products, namely, 9,10,13-trihydroxyoctadec-12-enoic acid, 9,12,13-trihydroxyoctadec-10-enoic acid, 9,10,11-trihydroxyoctadec-12-enoic, 11,12,13-trihydroxyoctadec-9-enoic acid, (10E,12E)-9-hydroxyoctadeca-10,12-dienoic acid, (9Z,11E)-13-hydroxyoctadeca-9,11-dienoic acid, (9E,11E)-13-hydroxyoctadeca-9,11-dienoic acid, 1-linoleoyl glycerol, α-linolenic acid, 2-hydroxypalmitic acid, 2-hydroxyoleic acid, linoleic acid, (9Z,11E)-13-oxooctadeca-9,11-dienoic acid, and octacosa-6,9,19,22-tetraen. Herein, we present the isolation, structure determination, and sensory activity of these molecules. Depending on their structure, the isolated compounds showed human bitter recognition thresholds between 0.06 and 0.99 mmol/L in water.

The worldwide increasing demand in proteins for human nutrition and animal feeding leads to a growing interest in novel protein sources. Therefore, rapeseed as an established raw material for the production of edible oils could be a promising alternative, as large amounts of press cakes and residues of oil extraction are available. Integrated fractionizing processes for simultaneous oil and protein isolation using aqueous-alcoholic extraction or adsorption techniques open many opportunities for new protein ingredients from rapeseed. The present manuscript compares two strategies to identify a suitable process for achieving highly functional ingredients for the use in food applications such as sausages, bakery products or mayonnaise. One process was based on hulling of the rapeseed kernels followed by an aqueous-alcoholic-extraction of the de-oiled flour. Based on this process, protein ingredients with about 60% protein content, but only poor functional properties could be produced. The application concentration of this ingredient was limited to 2%, because of oily and strawy off-flavors. Isolates with protein contents higher than 90% and improved sensory and functional properties could be achieved with an aqueous extraction followed by adsorption of secondary plant metabolites on specific resins and an ultrafiltration of the aqueous extract. This process enables the production of protein isolates with reduced off-flavors and optimized functional profiles. In several food applications a very promising utilization potential of these ingredients could be confirmed. Keywords: Food ingredients / plant protein / rapeseed / extraction / techno-functional properties Résumé-Protéines de colza : méthodes de production et champs d'application potentiels. La demande mondiale croissante en protéines destinées à l'alimentation humaine et animale génère un intérêt grandissant pour les nouvelles sources de protéines. Aussi, la graine de colza, en tant que matière première utilisée de longue date pour la production d'huiles comestibles, pourrait représenter une alternative prometteuse, puisque de grandes quantités de tourteaux et de résidus d'extraction de l'huile sont disponibles. Les process de fractionnement intégré pour isoler simultanément l'huile et la protéine, utilisant l'extraction hydro-alcoolique ou des techniques d'adsorption, ouvrent de nombreuses opportunités pour des nouveaux ingrédients protéiques issus de la graine de colza. Le manuscrit présenté compare deux stratégies d'identification d'un procédé approprié permettant de réaliser des ingrédients fortement fonctionnels pour des applications alimentaires comme les saucisses, les produits de boulangerie ou la mayonnaise. Un process est basé sur le dépelliculage de graines de colza suivi par une extraction hydro-alcoolique de la farine d'huile. Avec ce procédé, des ingrédients protéinés présentant une teneur en protéines d'environ 60 %, mais des propriétés fonctionnelles réduites, pourraient être produits. La concentration d'application de cet ingrédient a été limi...

Reduced-fat products can help to fight obesity and its associated health risks. To develop appealing products, both product-specific fat replacers and suitable analytical methods for the characterization of fat-associated properties are important. The rheology, tribology, texture, and spreadability of a reduced-fat mayonnaise with different concentrations of corn dextrin were analyzed to determine properties such as flow behavior, viscosity, lubricity, firmness, and stickiness. Additionally, a sensory panel analyzed the samples for their mouthfeel (creaminess, firmness, and stickiness). Correlations between the results of the instrumental methods suggested that the analytical effort for the future development of appealing reduced-fat food products can be reduced. In addition, several correlations were identified between the instrumental and the sensory data. Results from tribological measurements correlated with the sensory attribute of stickiness, suggesting that tribometry can complement or constitute an alternative to complex and expensive human sensory tests. Additionally, the use of Stevens’ power law showed a high correlation between the Kokini oral shear stress and the sensory attribute of creaminess. The instrumental texture properties (firmness, stickiness) also correlated with the sensory sensation. The identified correlations obtained from comparing different methods may help to estimate the possible applications of new fat replacers and facilitate innovative product development.