Staling in two canned lager beers stored at different temperatures from sensory analyses and consumer ranking

Two canned lagers, lager A (5% abv with late hop character) and lager B (4% abv) stored for 0, 7, 14, 21 and 28 days at 4, 12, 30 and 37°C were scored by trained sensory assessors (10) for liking and stale and related attributes of: cabbagy, cardboard, catty, grainy, honey, leathery, metallic, musty, skunky, and sour. Principal component analysis explained 80% data variance in 3 significant (p < 0.05) and 75% in 4 significant factors for A and B, respectively. In both lagers, aging correlated significantly with stale, cabbagy and musty and in A with metallic and sour and in B with catty and skunky. Partial least squares regression (PLS1) models showed good explanations: stale had regression coefficients of 0.88 (calibration) and 0.84 (validation) for A, and 0.96 and 0.91 respectively, for B; for liking 0.92 and 0.90 for A and 0.96 and 0.93 for B. For both lagers, liking was positively correlated with honey and grainy, and inversely with staling attributes. Lagers from 30°C were ranked for liking by 40 consumers against fresh as a hidden reference. Significant (p = 0.05) ranking of A, but not B, correlated with that of trained assessors

Relationships of overall estery aroma character in lagers with volatile headspace congener concentrations

In lager beers the intensity of “estery” aroma character is re-garded as an important component of sensory quality, but its origins are somewhat uncertain. Overall “estery” aroma intensity was predicted from capillary gas chromatographic (GC) data following solid phase micro extraction (SPME) of headspaces. Estery character was scored in 23 commercial lagers using rank-rating, allowing assessors (13) constant access to a range of appropriate standards. From univariate data analysis, all asses-sors behaved similarly and lagers fell into three significantly different groups: low (1), high (1) and intermediate (21). The quantification of 36 flavour volatiles by SPME of headspaces was reproducible and principal component analysis explained 91% total variance. Multiple linear regression could utilise only a restricted (26) set of flavour volatiles, whereas partial least square regression, that considered all flavour components, showed significant differences and improved prediction. How-ever, an artificial neural network that could compensate for non-linearities and interactions in ester perception gave the most robust prediction at R2 = 0.88

Geostrophic balance preserving interpolation in mesh adaptive shallow-water ocean modelling

The accurate representation of geostrophic balance is an essential requirement for numerical modelling of geophysical flows. Significant effort is often put into the selection of accurate or optimal balance representation by the discretisation of the fundamental equations. The issue of accurate balance representation is particularly challenging when applying dynamic mesh adaptivity, where there is potential for additional imbalance injection when interpolating to new, optimised meshes. In the context of shallow-water modelling, we present a new method for preservation of geostrophic balance when applying dynamic mesh adaptivity. This approach is based upon interpolation of the Helmholtz decomposition of the Coriolis acceleration. We apply this in combination with a discretisation for which states in geostrophic balance are exactly steady solutions of the linearised equations on an f-plane; this method guarantees that a balanced and steady flow on a donor mesh remains balanced and steady after interpolation onto an arbitrary target mesh, to within machine precision. We further demonstrate the utility of this interpolant for states close to geostrophic balance, and show that it prevents pollution of the resulting solutions by imbalanced perturbations introduced by the interpolation

Higher-Order Assembly of BRCC36-KIAA0157 Is Required for DUB Activity and Biological Function

BRCC36 is a Zn²⁺-dependent deubiquitinating enzyme (DUB) that hydrolyzes lysine-63-linked ubiquitin chains as part of distinct macromolecular complexes that participate in either interferon signaling or DNA-damage recognition. The MPN⁺ domain protein BRCC36 associates with pseudo DUB MPN⁻ proteins KIAA0157 or Abraxas, which are essential for BRCC36 enzymatic activity. To understand the basis for BRCC36 regulation, we have solved the structure of an active BRCC36-KIAA0157 heterodimer and an inactive BRCC36 homodimer. Structural and functional characterizations show how BRCC36 is switched to an active conformation by contacts with KIAA0157. Higher-order association of BRCC36 and KIAA0157 into a dimer of heterodimers (super dimers) was required for DUB activity and interaction with targeting proteins SHMT2 and RAP80. These data provide an explanation of how an inactive pseudo DUB allosterically activates a cognate DUB partner and implicates super dimerization as a new regulatory mechanism underlying BRCC36 DUB activity, subcellular localization, and biological function

Released cells, breath analysis and in-mouth analysis in flavour research

The flavour of a food or beverage is not perceived in a single event, but rather as a series of events experienced as the food is consumed. Recent methods in flavour research have taken account of this, and techniques have been developed to study flavour release in model systems (release cells or simulated mouths) and from the mouth or nose of assessors, while consuming foods. However, while there is agreement on the need in some cases for hydration or artificial saliva in simulated mouths, other parameters must be optimised on a case-by-case basis. Individual variability may still be a problem in breath analysis, and further work is required to determine the extent to which there are real differences in volatile profiles. The techniques of release cells and breath analysis must now be applied to provide data, which will allow flavour release to be modelled

Flavour in sourdough breads: a review

Flavour compounds are key elements for consumer acceptance and product identification in bread. One category of speciality breads, the sourdoughs have a fermentation process affected by a complex microflora of yeasts and lactic acid bacteria which confer specific flavour characteristics. Although yeasts have the primary leavening role, lactic acid bacteria (LAB), with trophic and non-trophic relationships, produce important flavour components. Sourdoughs are becoming important as consumers move away from pan breads towards speciality products. However, successful new product development requires an understanding of variations in carbohydrates' metabolism, roles of endogenous enzymes and interactions of microorganisms for generation of non-volatile and volatile flavour compounds. The potential of sourdough baking remains to be developed through specifications and optimisations of process conditions and introduction of exogenous enzymes and other ingredients. With effective new product development sourdough characteristics could be matched to relate with consumer tastes

Sensory profiling of aroma in Greek dry red wines using rank-rating and monadic scoring related to headspace composition

Rank-rating and monadic scoring were compared in profiling sensory aroma character of 27 Greek dry red wines with 16 attributes. In parallel wine headspace volatiles were quantified using solid-phase micro-extraction gas chromatography but not identified. In rank-rating, 14 aroma attributes showed discriminations with P<0.05 and 11 P<0.001. In scoring, 6 of 16 attributes showed P<0.05. Principal component analysis (PCA) explained 88% variance in rank-rating data, with six significant components (PCs), in scoring 40% in two PCs. PCA analysis of 83 common flavour volatiles explained 48% variance in six PCs. Partial least-squares regression (PLS1) modelling achieved more and better models for attributes using rank-rating, 8 of 14, than for scoring, 3 of 16; PLS2 explained greater variance in rank-rating. For wine sensory/instrumental correlation studies, rank-rating has distinct advantages over monadic scoring in deciding volatiles contributing to sensory character prior to identification strategies such as HRGC–mass spectrometry

Effects of high-pressure processing (HPP) on the microbiological, physico-chemical and sensory properties of fresh cheeses: a review

High pressure processing (HPP) is an increasingly popular food processing method that offers great potential within the food industry. The drive to use HPP is to provide minimally processed foods which are safe and have extended shelf-life that rival traditional methods of food processing. HPP is currently being applied to a wide variety of food products, although to date the dairy industry has received little attention. The present paper reviews the effects of HPP on fresh rennet- and acid-coagulated cheeses. In additional to modifying physicochemical and sensory characteristics, HPP is reported to inactivate certain micro-organisms typically found in cheeses. Pathogenic microorganisms such as Listeria monocytogenes and Escherichia coli which contaminate, spoil and limit the shelf-life of cheese can be controlled by HPP. HPP can also cause changes in milk rennet coagulation properties, produce a more continuous or homogeneous protein matrix in cheese, improve cheese structure, texture and yield, as well as reduce moisture content variations within fresh cheese blocks. Providing HPP can be operated economically, the use of pressure may be an attractive new method for the processing of cheese

Effects of high-pressure processing on proteolytic enzymes (and proteins) in cold-smoked salmon during refrigerated storage

The present paper describes the effects of high-pressure processing on the activity of proteolytic enzymes in cold-smoked salmon and enzyme extracts for pressures up to 300 MPa. The activities of the three enzymes, cathepsin B-like, cathepsin B + L-like and calpains were reduced at all pressure levels of up to 300 MPa (at ca. 9 °C for 20 min) in crude enzyme extracts prepared from cold-smoked salmon. Calpain almost completely inactivated at 300 MPa. High-pressure did not influence general proteolytic activity but activated the enzymes in muscles at higher pressure levels studied until 18 days of storage. An increase in the activity of cathepsin B + L-like and calpain was seen after 12 days of refrigerated storage. Myosin heavy chain was less affected at higher pressure levels (300 MPa) only as shown by Sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE) of proteins and further refrigerated storage had no obvious effects on proteins