The Impact of Vanilla and Lemon Aromas on Sensory Perception in Plant-Based Yogurts Measured with Static and Dynamic Methods.

The application of cross-modal interaction is a potential strategy to tackle the challenges related to poor sensory properties, such as thin mouthfeel, in plant-based yogurts. Thus, we aim to study the influence of aroma compounds possibly congruent with sweetness on the perceived sensory profile. Descriptive analysis and temporal dominance of sensations (n = 10 × 4) with a trained panel were conducted with and without a nose clip. One unflavored sample and samples flavored with either lemon or vanilla aromas were included (vanilla; 0.05%; 0.1%; lemon: 0.025%; 0.05%). Odor intensity, thick, sticky, and melting sensation, sweetness, and grain-like flavor were evaluated on an unstructured 10-cm line scale with anchors and reference samples. The results demonstrate how vanilla and lemon aromas suppressed grain-like flavor and enhanced odor intensity and sweetness. The following order was detected among samples in perceived sweetness intensity: unflavored < lemon < vanilla. The two sessions with and without nose clip differed statistically in sweetness, highlighting that the aromas impacted the perceived sweetness but not the mouthfeel in vanilla samples. The study suggests that congruent aromas could modify the perceived sweetness in plant-based yogurts; however, aroma or perceived sweetness does not impact the mouthfeel in plant-based yogurts. While the odor−taste interaction in such products is evident, the study highlights that aroma compounds alone do not modify mouthfeel.

Sperm selection with hyaluronic acid improved live birth outcomes among older couples and was connected to sperm DNA quality, potentially affecting all treatment outcomes.

STUDY QUESTION: What effects did treatment using hyaluronic acid (HA) binding/selection prior to ICSI have on clinical outcomes in the Hyaluronic Acid Binding sperm Selection (HABSelect) clinical trial? SUMMARY ANSWER: Older women randomized to the trial's experimental arm (selection of sperm bound to immobilized (solid-state) HA) had the same live birth rates as younger women, most likely a result of better avoidance of sperm with damaged DNA. WHAT IS KNOWN ALREADY: Recent randomized controlled trials (RCTs) investigating the efficacy of HA-based sperm selection prior to ICSI, including HABSelect, have consistently reported reductions in the numbers of miscarriages among couples randomized to the intervention, suggesting a pathological sperm-mediated factor mitigated by prior HA-binding/selection. The mechanism of that protection is unknown. STUDY DESIGN, SIZE, DURATION: The original HABSelect Phase 3 RCT ran from 2014 to 2017 and included 2752 couples from whom sperm samples used in control (ICSI) and intervention (Physiological IntraCytoplasmic Sperm Injection; PICSI) arms of the trial were stored frozen for later assessment of DNA quality (DNAq). The trial overlapped with its mechanistic arm, running from 2016 to 2018. PARTICIPANTS/MATERIALS, SETTING, METHODS: As miscarriage reduction was a significant secondary outcome of the trial, samples (n = 1247) selected for the mechanistic analysis were deliberately enriched for miscarriage outcomes (n = 92 or 7.4%) from a total of 154 miscarriages (5.6%) among all (n = 2752) couples randomized by stratified random sampling. Values from fresh semen samples for sperm concentration (mml), percentage forward progressive motility and percentage HA-binding score (HBS) were obtained before being processed by differential density gradient centrifugation or (rarely) by swim-up on the day of treatment. Surplus sperm pellets were recovered, aliquoted and cryopreserved for later analysis of DNAq using slide-based Comet, TUNEL, acridine orange (AO) and the sperm chromatin dispersion (SCD) assays. Following their classification into normal and abnormal sample subcategories based on reference values for sperm concentration and motility, relationships with HBS and DNAq were examined by Spearman correlation, Student's t-tests, Mann Whitney U tests, and logistic regression (univariable and multivariable). Parsimonious selection enabled the development of models for exploring and explaining data trends. Potential differences in future cumulative pregnancy rates relating to embryo quality were also explored. MAIN RESULTS AND THE ROLE OF CHANCE: Results from the 1247 sperm samples assayed for HBS and/or DNAq, generated data that were considered in relation to standard physiological measures of (sperm) vitality and to treatment outcomes. All measures of HBS and DNAq discriminated normal from abnormal sperm samples (P < 0.001). SCD correlated negatively with the Comet (r = -0.165; P < 0.001) and TUNEL assays (r = -0.200; P < 0.001). HBS correlated negatively with AO (r = -0.211; P < 0.001), Comet (r = -0.127; P < 0.001) and TUNEL (r = -0.214; P < 0.001) and positively with SCD (r = 0.255; P < 0.001). A model for predicting live birth (and miscarriage) rates included treatment allocation (odds ratio: OR 2.167, 95% CI 1.084-4.464, P = 0.031), female age (OR 0.301, 95% CI 0.133-0.761, P = 0.013, per decade) and the AO assay (OR 0.79, 95% CI 0.60-1. 02.761, P = 0.073, per 10 points rise). A model predicting the expected rate of biochemical pregnancy included male age (OR 0.464, 95% CI 0.314-0.674, P < 0.001, per decade) and the SCD assay (OR 1.04, 95% CI 1.007-1.075, P = 0.018, per 10 point rise). A model for conversion from biochemical to clinical pregnancy did not retain any significant patient or assay variables. A model for post-injection fertilization rates included treatment allocation (OR 0.83, 95% CI 0.75-0.91, P < 0.001) and the Comet assay (OR 0.950, 95% CI 0.91-1.00, P = 0.041). LIMITATIONS, REASONS FOR CAUTION: HABSelect was a prospective RCT and the mechanistic study group was drawn from its recruitment cohort for retrospective analysis, without the full benefit of randomization. The clinical and mechanistic aspects of the study were mutually exclusive in that measures of DNAq were obtained from residual samples and not from HA-selected versus unselected sperm. Models for fitting mechanistic with baseline and other clinical data were developed to compensate for variable DNAq data quality. HABSelect used a solid-state version of PICSI and we did not assess the efficacy of any liquid-state alternatives. PICSI reduced fertilization rates and did not improve the outlook for cumulative pregnancy rates. WIDER IMPLICATIONS OF THE FINDINGS: Notwithstanding the interventional effect on fertilization rates and possibly blastocyst formation (neither of which influenced pregnancy rates), poor sperm DNAq, reflected by lower HBS, probably contributed to the depression of all gestational outcomes including live births, in the HABSelect trial. The interventional avoidance of defective sperm is the best explanation for the equalization in live birth rates among older couples randomized to the trial's PICSI arm. As patients going forward for assisted conception cycles globally in future are likely to be dominated by an older demographic, HA-based selection of sperm for ICSI could be considered as part of their treatment plan. STUDY FUNDING/COMPETING INTEREST(S): The study was supported by the National Institute for Health Research (NIHR) EME (Efficacy and Mechanism Evaluation)-11-14-34. National Research Ethics Service approval 11/06/2013: 13/YH/0162. S.L. is CEO of ExamenLab Ltd (company number NI605309). TRIAL REGISTRATION NUMBER: ISRCTN99214271.

Physicochemical Properties and Mouthfeel in Commercial Plant-Based Yogurts.

There is a growing need for plant-based yogurts that meet consumer demands in terms of texture. However, more research is required to understand the relationship between physicochemical and mouthfeel properties in plant-based yogurts. The purpose of this study was to determine the physicochemical properties of five commercial plant-based yogurt alternatives with different chemical compositions, making comparisons to dairy yogurts and thick, creamy, thin, and watery mouthfeel sensations. The physicochemical parameters studied included large and small deformation rheology, particle size, soluble solids, acidity, and chemical composition. Significant differences in flow behavior and small deformation rheology were found between dairy- and plant-based yogurts. Among plant-based yogurts thick, creamy, thin, and watery mouthfeel sensations were strongly associated with steady shear rates and apparent viscosity. The results highlight the importance of large deformation rheology to advance the use of plant-based ingredients in the development of yogurt alternatives. Furthermore, this study demonstrates that dairy- and plant-based yogurts with a similar mouthfeel profiles may have different viscoelastic properties, which indicates that instrumental and sensory methods should not be considered substitutive but complementary methods when developing plant-based yogurts in a cost-effective and timely manner.

Impact of the COVID-19 pandemic on medical student placements in rural Queensland: A survey study.

OBJECTIVE: The COVID-19 pandemic has adversely impacted medical students' learning experiences. Students in one Australian Rural Clinical School were surveyed to investigate the impact of disruptions to clinical placements and satisfaction with educational changes implemented as a result of the pandemic. DESIGN: Cross-sectional survey. SETTING: The University of Queensland Rural Clinical School. METHODS: Students undertaking one or two years of study at the participating Rural Clinical School in November 2020. MAIN OUTCOME MEASURE: A 20-item anonymised survey with questions on personal health and safety, quality of clinical training experience, response to changes in learning and student environment, and progression to completion of the medical degree. RESULTS: The survey was completed by 124 students (76% response rate). Students were satisfied with the changes made to their learning to accommodate the disruptions to health service delivery and placements. Final year students were more satisfied with their learning experiences compared to their third-year counterparts. CONCLUSIONS: The Rural Clinical School implemented a range of academic and psychological support strategies which appear to have helped with mitigating mental health concerns experienced by students completing rural placements, who are already prone to experiencing social isolation. Strengthening communication between the academic and health service sectors can improve the quality of learning for medical students on placements.

Long-term antidepressant use in general practice: a qualitative study of GPs' views on discontinuation.

BACKGROUND: There is considerable concern about increasing antidepressant use, with Australians among the highest users in the world. Evidence suggests this is driven by patients on long-term use, rather than new prescriptions. Most antidepressant prescriptions are generated in general practice, and it is likely that attempts to discontinue are either not occurring or are proving unsuccessful. AIM: To explore GPs' insights about long-term antidepressant prescribing and discontinuation. DESIGN AND SETTING: A qualitative interview study with Australian GPs. METHOD: Semi-structured interviews explored GPs' discontinuation experiences, decision-making, perceived risks and benefits, and support for patients. Data were analysed using reflexive thematic analysis. RESULTS: Three overarching themes were identified from interviews with 22 GPs. The first, 'not a simple deprescribing decision', spoke to the complex decision-making GPs undertake in determining whether a patient is ready to discontinue. The second, 'a journey taken together', captured a set of steps GPs take together with their patients to initiate and set-up adequate support before, during, and after discontinuation. The third, 'supporting change in GPs' prescribing practices', described what GPs would like to see change to better support them and their patients to discontinue antidepressants. CONCLUSION: GPs see discontinuation of long-term antidepressant use as more than a simple deprescribing decision. It begins with considering a patient's social and relational context, and is a journey involving careful preparation, tailored care, and regular review. These insights suggest interventions to redress long-term use will need to take these considerations into account and be placed in a wider discussion about the use of antidepressants.

The effects of social group interventions for depression: Systematic review.

BACKGROUND: There is a growing prevalence of prolonged antidepressant use globally. Social group interventions may be an effective way to manage mild to moderate depression, especially with patients seeking to discontinue antidepressant use. This systematic review evaluates studies that used social group interventions to manage depression. METHODS: Studies published up to June 2019 in nine bibliographic databases were identified using search terms related to depression, social interventions, and social participation. Formal therapies for depression (cognitive behaviour therapy, music therapy) were excluded as they have been reviewed elsewhere. RESULTS: 24 studies met inclusion criteria; 14 RCTs, 6 non-randomised controlled trials and 4 pre-post evaluations. In total, 28 social group programs were evaluated, 10 arts-based groups, 13 exercise groups and 5 others. Programs ranged in 'dose' from 5 to 150 hours (M = 31 hours) across 4 to 75 weeks (M = 15 weeks) and produced effect sizes on depression in the small to very large range (Hedge's g = .18 to 3.19, M = 1.14). A regression analysis revealed no participant variables, study variables or intervention variables were related to effect size on depression. LIMITATIONS: Risks of bias were found, primarily in the non-randomised studies, which means the findings must be regarded as preliminary until replicated. CONCLUSION: These findings indicate that social group interventions are an effective way to manage mild to moderate depression symptoms in a variety of populations. This approach may also help to prevent relapse among patients tapering off antidepressant medication.

Recruiting and retaining general practitioners in rural practice: systematic review and meta-analysis of rural pipeline effects.

OBJECTIVE: To synthesise quantitative data on the effects of rural background and experience in rural areas during medical training on the likelihood of general practitioners practising and remaining in rural areas. STUDY DESIGN: Systematic review and meta-analysis of the effects of rural pipeline factors (rural background; rural clinical and education experience during undergraduate and postgraduate/vocational training) on likelihood of later general practice in rural areas. DATA SOURCES: MEDLINE (Ovid), EMBASE, Informit Health Collection, and ERIC electronic database records published to September 2018; bibliographies of retrieved articles; grey literature. DATA SYNTHESIS: Of 6709 publications identified by our search, 27 observational studies were eligible for inclusion in our systematic review; when appropriate, data were pooled in random effects models for meta-analysis. Study quality, assessed with the Newcastle-Ottawa scale, was very good or good for 24 studies, satisfactory for two, and unsatisfactory for one. Meta-analysis indicated that GPs practising in rural communities was significantly associated with having a rural background (odds ratio [OR], 2.71; 95% CI, 2.12-3.46; ten studies) and with rural clinical experience during undergraduate (OR, 1.75; 95% CI, 1.48-2.08; five studies) and postgraduate training (OR, 4.57; 95% CI, 2.80-7.46; eight studies). CONCLUSION: GPs with rural backgrounds or rural experience during undergraduate or postgraduate medical training are more likely to practise in rural areas. The effects of multiple rural pipeline factors may be cumulative, and the duration of an experience influences the likelihood of a GP commencing and remaining in rural general practice. These findings could inform government-led initiatives to support an adequate rural GP workforce. PROTOCOL REGISTRATION: PROSPERO, CRD42017074943 (updated 1 February 2018).

Cryopreservation of primary cultures of mammalian somatic cells in 96-well plates benefits from control of ice nucleation.

Cryopreservation of mammalian cells has to date typically been conducted in cryovials, but there are applications where cryopreservation of primary cells in multiwell plates would be advantageous. However excessive supercooling in the small volumes of liquid in each well of the multiwell plates is inevitable without intervention and tends to result in high and variable cell mortality. Here, we describe a technique for cryopreservation of adhered primary bovine granulosa cells in 96-well plates by controlled rate freezing using controlled ice nucleation. Inducing ice nucleation at warm supercooled temperatures (less than 5 °C below the melting point) during cryopreservation using a manual seeding technique significantly improved post-thaw recovery from 29.6% (SD = 8.3%) where nucleation was left uncontrolled to 57.7% (9.3%) when averaged over 8 replicate cultures (p < 0.001). Detachment of thawed cells was qualitatively observed to be more prevalent in wells which did not have ice nucleation control which suggests cryopreserved cell monolayer detachment may be a consequence of deep supercooling. Using an infra-red thermography technique we showed that many aliquots of cryoprotectant solution in 96-well plates can supercool to temperatures below -20 °C when nucleation is not controlled, and also that the freezing temperatures observed are highly variable despite stringent attempts to remove contaminants acting as nucleation sites. We conclude that successful cryopreservation of cells in 96-well plates, or any small volume format, requires control of ice nucleation.

Is three a crowd? Impact of the presence of a medical student in the general practice consultation.

OBJECTIVES: To determine the impact of the presence of a medical student on the satisfaction and process of the general practice consultation from the perspective of the general practitioner (GP), patient and student. METHODS: An observational study was conducted in regional general practices accepting third-year medical students. General practitioners, patients and medical students were asked to complete a questionnaire after each consultation. The main outcome measures were: patient satisfaction; GPs' perceived ability to deliver care; medical students' satisfaction with their learning experience; length of consultation; and patient waiting times. RESULTS: Of the 26 GP practices approached, 11 participated in the study (42.3%). Patients returned 477 questionnaires: 252 consultations with and 225 without a student present. Thirteen GPs completed 473 questionnaires: 248 consultations with and 225 without a student. Twelve students attended 255 consultations. Most patients (83.5%) were comfortable with the presence of a student. There were no significant differences between consultations with and without a student regarding the time the patients spent in the waiting room (p = 0.6), the patients' perspectives of how the GPs dealt with their presenting problems (100% versus 99.2%; p = 0.6) and overall satisfaction with the consultation (99.2% versus 99.1%; p = 0.5). Despite these reassuring findings, a significantly higher proportion of patients in consultations without students raised sensitive or personal issues (26.3% versus 12.6%; p < 0.001). There were no statistically significant differences in the lengths of consultations with and without students (81% versus 77% for 6-20 minutes consultation; p = 0.1) or in the GPs' perceptions of how they effectively managed the presenting problem (95.1% versus 96.0%; p = 0.4). Students found that the majority (83.9%) of the 255 consultations were satisfactory for learning. CONCLUSIONS: The presence of a medical student during the GP consultation was satisfactory for all participant groups. These findings support the ongoing and increased placement of medical students in regional general practice. Medical educators and GPs must recognise that patients may not raise personal issues with a student present.

Single Enzyme Experiments Reveal a Long-Lifetime Proton Leak State in a Heme-Copper Oxidase.

Heme-copper oxidases (HCOs) are key enzymes in prokaryotes and eukaryotes for energy production during aerobic respiration. They catalyze the reduction of the terminal electron acceptor, oxygen, and utilize the Gibbs free energy to transport protons across a membrane to generate a proton (ΔpH) and electrochemical gradient termed proton motive force (PMF), which provides the driving force for the adenosine triphosphate (ATP) synthesis. Excessive PMF is known to limit the turnover of HCOs, but the molecular mechanism of this regulatory feedback remains relatively unexplored. Here we present a single-enzyme study that reveals that cytochrome bo3 from Escherichia coli, an HCO closely homologous to Complex IV in human mitochondria, can enter a rare, long-lifetime leak state during which proton flow is reversed. The probability of entering the leak state is increased at higher ΔpH. By rapidly dissipating the PMF, we propose that this leak state may enable cytochrome bo3, and possibly other HCOs, to maintain a suitable ΔpH under extreme redox conditions.

Micelle formation of coenzyme Q10 with dipotassium glycyrrhizate using inclusion complex of coenzyme Q10 with γ-cyclodextrin.

Micelles can be formed from coenzyme Q10 (CoQ10) and dipotassium glycyrrhizate (GZK2) by using an inclusion complex of CoQ10 with γ-cyclodextrin (γ-CD). The mechanism of micelle formation was kinetically investigated. Adding GZK2 to a supersaturated solution of the CoQ10/γ-CD inclusion complex led to a linear increase in the solubility of CoQ10 due to the formation of micelles of CoQ10 when the molar ratio of GZK2/γ-CD increased to ∼1.6, after which the concentration remained constant. The equilibrium constant K for micelle formation was 0.68 (-) and the ratio of GZK2 to CoQ10 was 1. These results suggest that the formation of CoQ10 micelles with GZK2 might proceed via the displacement of CoQ10 by GZK2 in the γ-CD cavity followed by the formation of CoQ10 micelles.

Study of oxygen transfer across milk proteins at an air-water interface with scanning electrochemical microscopy.

Scanning electrochemical microscopy (SECM) combined with a Langmuir trough was used for studying oxygen transfer across protein films at an air-water interface. The method allows the comparison of the oxygen permeability of different emulsifiers without any concerns of interference of atmospheric oxygen. Two milk proteins, ß-lactoglobulin and ß-casein, were compared, and the permeabilities obtained were for ß-casein PD ≈ 2.2 × 10(-7) cm(2)/s and for ß-lactoglobulin PD ≈ 0.6 × 10(-7) cm(2)/s, which correspond to the lowest limit of the diffusion coefficients and are 2 orders of magnitude lower than the diffusion coefficient of oxygen in water, yet several orders of magnitude higher than previously reported for milk protein films. The method allows characterization of the oxygen barrier properties of liquid interfacial films, which is of crucial importance for understanding the role of the interface in the inhibition of oxygen transport and developing modified interfaces with higher oxygen blocking efficacy.

Interfacial protein engineering for spray-dried emulsions - part I: effects on protein distribution and physical properties.

Distribution of protein and oil in aqueous and spray-dried emulsions and the effect of protein cross-linking on emulsion properties and matrix-water interactions were investigated. Sodium caseinate and sunflower oil were used to make emulsions which were spray dried using maltodextrin as a wall material. 3% Na-caseinate concentration showed optimum emulsion and process stability as observed in CLSM images, droplet size data and in the amount of heptane-extractable oil from spray-dried emulsions. Transglutaminase cross-linking prior to emulsification slightly increased the amount of protein both on the oil droplet interface and on the particle surface as confirmed by analysis of continuous phase protein in the feed emulsion and by XPS measurements from the powder surface. DSC and water sorption measurements were used to study the physical state of the matrix. Glass transition occurred between RH 54% and 75% at room temperature and it was not affected by cross-linking.

Interfacial protein engineering for spray-dried emulsions - part II: oxidative stability.

The aim of this work was to investigate how the oxidative stability of encapsulated oil is affected by the humidity response of a Na-caseinate-maltodextrin matrix. Furthermore, the effect of modification of the interfacial Na-caseinate layer through cross-linking was studied. For this purpose, two model spray-dried emulsions containing sunflower oil, maltodextrin, and either non-cross-linked or cross-linked Na-caseinate were stored at different relative humidities (RHs; ∼0%, 11%, 33%, 54%, and 75%). Increasing RH improved the oxidative stability of the spray-dried emulsions. This behaviour was mainly linked to the loss of individual powder particles upon caking and collapsing of the matrix at RH 75%. Oxidation of non-encapsulated surface lipids with a proportion of ca. 5% of total lipids was only twofold compared to total lipids. Excess protein on particle surfaces may have delayed oxidation, e.g., by its radical scavenging activity. Under several storage conditions, cross-linking of the protein slightly improved the oxidative stability.

Transglutaminase catalyzed cross-linking of sodium caseinate improves oxidative stability of flaxseed oil emulsion.

Sodium caseinate was modified by transglutaminase catalyzed cross-linking reaction prior to the emulsification process in order to study the effect of cross-linking on the oxidative stability of protein stabilized emulsions. The extent of the cross-linking catalyzed by different dosages of transglutaminase was investigated by following the ammonia production during the reaction and using SDS-PAGE gel. O/W emulsions prepared with the cross-linked and non-cross-linked sodium caseinates were stored for 30 days under the same conditions. Peroxide value measurement, oxygen consumption measurement, and headspace gas chromatography analysis were used to study the oxidative stability of the emulsions. The emulsion made of the cross-linked sodium caseinate showed an improved oxidative stability with reduced formation of fatty acid hydroperoxides and volatiles and a longer period of low rate oxygen consumption. The improving effect of transglutaminase catalyzed cross-linking could be most likely attributed to the enhanced physical stability of the interfacial protein layer against competitive adsorption by oil oxidation products.

Charge modifications to improve the emulsifying properties of whey protein isolate.

Whey protein isolate was modified by ethylene diamine in order to shift its isoelectric point to an alkaline pH. The extent of the modification was studied using SDS-PAGE and MALDI-TOF mass spectrometry. The modified whey proteins were used as an emulsifier to stabilize oil-in-water emulsions at acidic and neutral pH ranges, and their emulsifying properties were compared with that of the unmodified whey proteins and with the previously studied ethylene diamine modified sodium caseinate. The emulsifying activity of the modified whey proteins was similar to that of the unmodified ones, but the stability of an emulsion at pH 5 was significantly improved after the modification. Charge and coverage of droplet surface and the displacement of the interfacial proteins by surfactant Tween 20 were further studied as a function of pH. As compared with the unmodified whey proteins, the modified ones were proven to cover the interface more efficiently with extensive surface charge at pH 5, although the interfacial layer was less resistant to the surfactant displacement.

Loosening of globular structure under alkaline pH affects accessibility of ß-lactoglobulin to tyrosinase-induced oxidation and subsequent cross-linking.

Globular proteins such as ß-lactoglobulin (BLG) are poorly accessible to enzymes. We have studied susceptibility of BLG to oxidation by Trichoderma reesei (TrTyr) and Agaricus bisporus (AbTyr) tyrosinases and subsequent intermolecular cross-linking with respect to pH-induced structural changes. We evaluated pH-induced structural changes in BLG using circular dichroism, tryptophan fluorescence and small angle X-ray scattering (SAXS) measurements, where after these results were correlated with the analysis of cross-linking by sodium dodecyl sulphate polyacrylamide gel electrophoresis. Oxygen consumption measurement and changes in radii of gyration determined by SAXS during the enzyme-induced oxidation at the respective reaction conditions were also followed. Intermolecular cross-linking of BLG by TrTyr was found at pH 9 but not at pH 7.5. AbTyr was unable to catalyze cross-linking at pH 7.5 or pH 9. Increased accessibility and cross-linking by TrTyr was addressed to loosening of the three dimensional structure of the protein, increased flexibility of the backbone as well as partial hydrolysis. In addition to basic research of the effect of protein folding on enzymatic cross-linking the research results have significance on the exploitation of TrTyr at alkaline conditions.

Improving laccase catalyzed cross-linking of whey protein isolate and their application as emulsifiers.

Whey protein isolate (WPI) was chemically modified by vanillic acid in order to enhance its cross-linkability by laccase enzyme. Incorporation of methoxyphenol groups created reactive sites for laccase on the surface of the protein and improved the efficiency of cross-linking. The vanillic acid modified WPI (Van-WPI) was characterized using MALDI-TOF mass spectrometry, and the laccase-catalyzed cross-linking of Van-WPI was studied. Furthermore, the vanillic acid modification was compared with the conventional approach to improve laccase-catalyzed cross-linking by adding free phenolic compounds. A small extent of the vanillic acid modification significantly improved the cross-linkability of the protein and made it possible to avoid color formation in a system that is free of small phenolic compounds. Moreover, the potential application of Van-WPI as emulsifier and the effect of cross-linking on the stability of Van-WPI emulsion were investigated. The post-emulsification cross-linking by laccase was proven to enhance the storage stability of Van-WPI emulsion.

Crosslinking food proteins for improved functionality.

Different possibilities for protein crosslinking are examined in this review, with special emphasis on enzymatic crosslinking and its impact on food structure. Among potential enzymes for protein crosslinking are transglutaminase (TG) and various oxidative enzymes. Crosslinking enzymes can be applied in cereal, dairy, meat, and fish processing to improve the texture of the product. Most of the current commercial applications are based on TG. The reaction mechanisms of the crosslinking enzymes differ, which in turn results in different technological properties.