Markeri redoks statusa kod pacijenata sa nealkoholnom masnom bolešću jetre

Nonalcoholic fatty liver disease (NAFLD) is the most common chronic liver disease, present in up to 30% of the adult population worldwide (1). Triglycerides accumulation in hepatocytes (steatosis) represents the root cause of NAFLD and is associated with oxidative stress, which could further lead to fibrosis and cell death of hepatocytes (2). The aim of this research was to identify redox status markers for predicting the risk of developing steatosis. 158 participants were included. Steatosis was confirmed by ultrasound in 101 subjects, while the remaining 57 were in the control group. The following markers of redox status were determined in serum and plasma samples of all subjects: superoxide dismutase 1 (SOD1), paraoxonase (PON1), malondialdehyde (MDA) and superoxide anion (O2.-). For this purpose, spectrophotometric methods and enzyme immunosorbent assays were used. SOD1 was statistically significantly higher (P<0.001), while O2 .- was significantly lower in the patient group (P<0.001). SOD1 was significantly negatively correlated with O2.- (ρ= -0.494, P<0.001) and MDA (ρ= -0.242, P=0.002). Univariate binary logistic regression analysis showed a positive association between SOD1 and the presence of steatosis (OR=1.018, 95% CI 1.005-1.031; P=0.005), as well as a negative association between O2 .- and the presence of steatosis (OR=0.959, 95% CI 0.941-0.978; P<0.001). Multivariate analysis singled out SOD1 (OR=1.024, 95% CI 1.006-1.041; P=0.007) and O2.- (OR=0.965, 95% CI 0.942-0.989; P=0.004) as independent predictors for the presence of steatosis in our subjects. The redox status parameters, SOD1 and O2, respectively, showed a positive and negative prediction of the presence of statosis in our subjects.Nealkoholna masna bolest jetre (eng. nonalcoholic fatty liver disease, NAFLD) je najčešće hronično oboljenje jetre, prisutno i u do 30% adultne populacije širom sveta (1). Značajnu ulogu u nastanku NAFLD ima akumulacija triglicerida u hepatocitima – steatoza, koja je povezana sa oksidativnim stresom, a koji dalje vodi fibrozi i ćelijskoj smrti hepatocita (2). Cilj ovog istraživanja bio je identifikacija markera redoks statusa za predviđanje rizika za nastanak steatoze. Studija je obuhvatila 158 ispitanika iz Kliničko bolničkog centra Zemun. Steatoza je potvrđena ultrazvukom kod 101 ispitanika, dok je preostalih 57 činilo kontrolnu grupu. U uzorcima seruma i plazme svih ispitanika određeni su sledeći markeri redoks statusa: superoksid dismutaza 1 (SOD1), paraoksonaza (PON1), malondialdehid (MDA) i superoksidni anjon (O2.-). U tu svrhu korišćene su spektrofotometrijske metode i enzimski imunosorbentni testovi. SOD1 je bila statistički značajno viša (P<0,001), dok O 2.- značajno niži u grupi pacijenata (P<0,001), dok se PON1 i MDA nisu značajno razlikovali između grupa. SOD1 je bila u značajnoj negativnoj korelaciji sa O 2.- (ρ=-0,494, P<0,001) i MDA (ρ= - 0,242, P=0,002). Univarijatna binarna logistička regresiona analiza je pokazala pozitivnu asocijaciju između SOD1 i prisustva steatoze (OR=1,018, 95% CI 1,005-1,031; P=0,005), kao i negativnu asocijaciju između O 2.- i prisustva steatoze (OR=0,959, 95% CI 0,941-0,978; P<0,001). Multivarijantna analiza je izdvojila SOD1 (OR=1,024, 95% CI 1,006-1,041; P=0,007) i O2.- (OR=0,965, 95% CI 0,942-0,989; P=0,004) kao nezavisne prediktore za prisustvo steatoze kod naših ispitanika. Parametri redoks statusa, SOD1 i O 2.- redom, su pokazali pozitivnu, odnosno negativnu predikciju prisustva statoze kod naših ispitanika.VIII Kongres farmaceuta Srbije sa međunarodnim učešćem, 12-15.10.2022. Beogra

Biochemical and funcional properties of egg white hydrolysates produced by different proteases

Enzymatic hydrolysis of egg white proteins (EWPs) has shown a great potential to improve their functional properties such as increased solubility, stability, and digestibility while still retaining their nutrition value. The high selectivity and mild reaction conditions associated with the enzymatic process have made this approach an attractive alternative in the production of EWPs with improved functional properties, which are often difficult to obtain by conventional chemical route. Moreover, the inherent specificity of various proteolytic enzymes should control the nature and extent of hydrolysis and thus the functional properties of the product. The focus of this work is to find the best combination of enzymes and the mode of both substrate pretreatment and process implementation for improvement of the overall hydrolysates` quality. For this purpose EWP solution was hydrolysed with several enzymes using both, one-step and two-step hydrolysis in a stirred stirred-tank reactor employing an enzyme to protein substrate weight ratio previously selected to obtain the desired level of conversion in the first step within a time period from about 20 to about 75 minutes depending of protease used. The obtained hydrolysates were then tested on antioxidant activity, flavour, solubility, digestibility emulsifying activity, foaming capacity and stability. Selected results have been presented in Figure 1. The application of two-step enzymatic process, based on the use of the bacterial alkaline protease in the first step, and then the introduction a more specific protease in the second step to selectively reduce the bitter peptides, seemed to be advantageous

Effects of hydrolysis degree and type of protease on antioxidant activity and functionality of egg white protein hydrolysates

Enzymatic hydrolysis of egg white proteins has shown great potential to improve their functional properties such as increased solubility, stability, and digestibility, and to reduce protein allergenicity while still retaining their nutrition value. However, the enzymatic hydrolysis process is still poorly defined and difficult to control at the industrial scale resulting in peptide\ud mixtures poorly characterized and with unpleasant bitter taste that make them unsuitable for human consumption. Thus, the hydrolysis reaction must be carefully controlled in order to produce new value-added egg white hydrolysates with improved properties and specialized functionality. In this paper egg white protein solution was hydrolysed with several enzymes using both, one-step and two-step hydrolysis. The hydrolysate was then tested on antioxidant\ud activity, flavour, solubility, digestibility emulsifying activity, foaming capacity and stability. All\ud protein hydrolysates showed higher solubility and digestibility than intact proteins, especially at\ud pHs near isoelectric point of egg white proteins. Moreover, all hydrolysates had better functional properties, except emulsifying activity, than the native protein solution

Antioksidativna aktivnost hidrolizata belanceta i njegovih frakcija dobijenih membranskom ultrafiltracijom

Hidrolizom proteina belanceta dobijaju se bioaktivni peptidi koji imaju različita biološka svojstva. U ovom radu korišćena je tehnologija ultrazvuka visokog intenziteta kao pretretman pripreme proteina belanceta koji su zatim hidrolizovani različitim vrstama proteaza u jednostepenom i dvostepenom postupku. Dobijeni hidrolizati su razdvojeni korišćenjem ultrafiltracionih membrana promera 1, 10 i 30 kDa i dobijenim frakcijama je ispitana antioksidativna aktivnost. Među frakcijama veličine manje od 1 kDa koje sadrže bioaktivne peptide, najveću antioksidativnu aktivnost je pokazao ultrazvučno pretretiran hidrolizat nastao delovanjem alkalaza-flevorzima u dvostepenom enzimskom postupku

Kinetic model of the hydrolysis of egg white proteins by Alcalase

The kinetics of hydrolysis of egg white proteins by Alcalase 2.4L (protease from Bacillus licheniformis) was investigated. In this paper, the main objective was to determine the appropriate empirical model for the proteolytic hydrolysis of egg white. A logarithmic equation X = (1/b) ln (1 + abt) indicating the relationship between the degree of hydrolysis (DH) and time was established. Experimental data were successfully fitted with kinetic model taking into account the enzyme inactivation and substrate inhibition, and related kinetic constants were determined. The kinetic study was performed at optimum process parameters: initial enzyme concentration of Alcalase 2.4L, initial substrate concentration of the egg white proteins and different temperatures of the reaction. The kinetic and thermodynamic constants for reaction of hydrolysis (Ki = 320.07 mg cm-3, k2 =0.0104 min-1, kd = 0.0743 min-1, Ea = 103.04 kJ mol-1, Ed = 99.52 kJ mol-1) were responsible for the empirical equation. Kinetic constants of the hydrolysis were determined, and good congruence between the model and experimental data was achieved. The results of nonlinear regression of the proposed kinetic model agreed with the experimental data, thus the kinetic equations can be used to fit the enzymatic hydrolysis process of egg white protein and to optimize the operating parameters for the bioreactor design