Development of separation techniques for complex characterization of plant proteins and carbohydrates

In the Research Group of Cereal Science and Food Quality at the Department of Applied Biotechnology and Food Science of BME, separation technique has been part of the methods used for the complex quality assessment of food and food ingredients for a long time. Our colleagues working in our current and predecessor department achieved serious results with the help of their separation technique methods, for example in the analysis of protein and carbohydrate composition, analysis of lipids (fatty acids), quantitative and qualitative evaluation of biogenic amines and amino acids, etc. In addition to determining the composition of the raw material, the impact of different molecules on quality and technological properties was always an important question. It was always possible to investigate this using the modern tools and methods of the time, so the application of gel chromatography, high-performance liquid chromatography, gas chromatography and electrophoretic techniques determined the quality of both research and education. In recent years, the research group has mainly dealt with the quality of grains, their composition, their technological potential and their evaluation from a food safety aspect. For the research of these areas, molecular level (mainly protein and fibre composition) examinations have become essential, for which modern electrophoretic and chromatographic methods are excellent tools. However, their proper application is a great challenge, because in most cases, serious method development and/or method adaptation and partial validation tasks are required for their routine use. In the following, we provide a brief overview of the projects and results achieved in our research group in the field of separation techniques through a few application examples

Investigation of the Role of Arabinoxylan on Dough Mixing Properties in Native and Model Wheat Dough Systems

The aim of this work was to investigate and compare the effect of arabinoxylan (AX) addition and incorporation on the mixing properties of native and model doughs of different wheat types, to get more insight into the role of AXs in dough formation. In the experiments, flour samples of a wheat variety (normal starch type) and two wheat lines (waxy and high amylose) were used. Model doughs were composed by fractionating flours into starch and gluten followed by subsequent reconstitution according to their original gluten to starch ratio. AX isolate was dosed in 1% and 3% to the native and model doughs. Incorporation of AX was performed by reduction and re-oxidation of wheat dough with dithiothreitol (DTT) and KIO3, respectively. Model doughs behaved similarly to native doughs thus were found appropriate for the model experiments. In general, higher AX level resulted higher dough consistency in every dough system compared to the corresponding base dough, however, the extent of the growth was different. In case of assumed AX incorporation only small differences were found in the mixing properties compared to AX addition. Based on sodium dodecyl sulfate–polyacrylamide gel electrophoresis (SDS–PAGE) analysis, some minor but clear changes were observed in the protein subunit profile of AX containing doughs compared to base doughs, but no difference was identified between doughs made by AX addition and AX incorporation. However, the characterization of the gluten-AX interactions requires more detailed investigation, in which a pure gluten-starch-AX model system can offer a valuable, well-defined matrix

Elválasztástechnikai módszerek fejlesztése növényi fehérjék és szénhidrátok komplex jellemzésére

A BME Alkalmazott Biotechnológia és Élelmiszertudományi Tanszékén működő Gabonatudományi és Élelmiszerminőség Kutatócsoportban az elválasztástechnika már hosszú idő óta részét képezi az élelmiszerek, élelmiszer összetevők komplex minőségi értékeléséhez alkalmazott módszereknek. A jelenlegi és jogelőd tanszékünkön dolgozó kollégáink komoly eredményeket értek el az elválasztástechnikai módszereik segítségével például a fehérje és szénhidrát összetétel vizsgálatában, a lipidek (zsírsavak) analízisében, a biogén aminok és aminosavak mennyiségi és minőségi értékelésében, stb. Az alapanyag összetételi meghatározása mellett fontos kérdés volt az egyes molekulák minőségre, technológiai tulajdonságokra gyakorolt hatása. Ezt mindig az adott korban korszerűnek számító eszközöket és módszereket felhasználva volt lehetőség vizsgálni, így gélkromatográfia, nagyhatékonyságú folyadékkromatográfia, gázkromatográfia és elektroforetikus technikák alkalmazása fémjelezte mind a kutatás, mind az oktatás színvonalát. Az elmúlt években a kutatócsoportunkban főként a gabonák minőségével, összetételükkel, technológia potenciáljukkal és élelmiszerbiztonsági szempontú értékelésükkel foglalkoztunk. Ezeknek a területeknek a kutatására a részletes molekuláris szintű (elsősorban fehérje és rost összetételi) vizsgálatok elengedhetetlenné váltak, amelyek kiváló eszközei a modern elektroforetikus és kromatográfiás módszerek. Ezek megfelelő alkalmazása azonban nagy kihívást jelent, mert rutinszerű használatukhoz a legtöbb esetben komoly módszerfejlesztési és/vagy módszeradaptálási, részleges validálási feladatok elvégzése szükséges. A következőkben néhány alkalmazási példán keresztül rövid áttekintést adunk a kutatócsoportunkban az elválasztástechnika területét érintő projektekről és elért eredményeinkről

Age-dependent parathormone levels and different CKD-MBD treatment practices of dialysis patients in Hungary - results from a nationwide clinical audit

BACKGROUND: Achieving target levels of laboratory parameters of bone and mineral metabolism in chronic kidney disease (CKD) patients is important but also difficult in those living with end-stage kidney disease. This study aimed to determine if there are age-related differences in chronic kidney disease-mineral and bone disorder (CKD-MBD) characteristics, including treatment practice in Hungarian dialysis patients. METHODS: Data were collected retrospectively from a large cohort of dialysis patients in Hungary. Patients on hemodialysis and peritoneal dialysis were also included. The enrolled patients were allocated into two groups based on their age (=65 years). Characteristics of the age groups and differences in disease-related (epidemiology, laboratory, and treatment practice) parameters between the groups were analyzed. RESULTS: A total of 5008 patients were included in the analysis and the mean age was 63.4+/-14.2 years. A total of 47.2% of patients were women, 32.8% had diabetes, and 11.4% were on peritoneal dialysis. Diabetes (37.9% vs 27.3%), bone disease (42.9% vs 34.1%), and soft tissue calcification (56.3% vs 44.7%) were more prevalent in the older group than the younger group (p<0.001 for all). We found an inverse relationship between age and parathyroid hormone (PTH) levels (p<0.001). Serum PTH levels were lower in patients with diabetes compared with those without diabetes below 80 years (p<0.001). Diabetes and age were independently associated with serum PTH levels (interaction: diabetes x age groups, p=0.138). Older patients were more likely than younger patients to achieve laboratory target ranges for each parameter (Ca: 66.9% vs 62.1%, p<0.001; PO4: 52.6% vs 49.2%, p<0.05; and PTH: 50.6% vs 46.6%, p<0.01), and for combined parameters (19.8% vs 15.8%, p<0.001). Older patients were less likely to receive related medication than younger patients (66.9% vs 79.7%, p<0.001). CONCLUSIONS: The achievement of laboratory target ranges for bone and mineral metabolism and clinical practice in CKD depends on the age of the patients. A greater proportion of older patients met target criteria and received less medication compared with younger patients

Physical performance tasks were linked to the PROMIS physical function metric in patients undergoing hemodialysis

Objectives: To investigate whether a multi-item performance outcome measure, the physical performance test (PPT), can be calibrated to a common scale with patient-reported outcome measures, using the Patient-Reported Outcomes Measurement Information System (PROMIS) physical function (PF) metric. Study Design and Setting: We analyzed baseline data (N = 1,113) from the CONVINCE study, an international trial in end-stage kidney disease patients comparing high-dose hemodiafiltration with high-flux hemodialysis. Assumptions of item response theory (IRT) modelling were investigated for the combined set of the nine-item PPT and a four-item PROMIS PF short form (PROMIS-PF4a). We applied unidimensional IRT linking for calibrating the PPT to the PROMIS PF metric. Results: Although some evidence for multidimensionality was found, classical test statistics (Cronbach's Alpha = 0.93), Mokken (Loevinger's H = 0.50), and bifactor analysis (explained common variance = 0.65) indicated that PPT and PROMIS-PF4a items can be used to assess a common PF construct. On the group level, the agreement between PROMIS-PF4a and linked PPT scores was stable across several subsamples. On the individual level, scores differed considerably. Conclusion: We found preliminary evidence that the PPT can be linked to the PROMIS PF metric in hemodialysis patients, enabling group comparisons across patient-reported outcome and performance outcome measures. Alternative linking methods should be applied in future studies using a more comprehensive PROMIS PF item set