ABSTRACT
Se evaluó el efecto de la temperatura sobre la desnaturalización de proteínas y la reacción de Maillard en leche entera y descremada con lactosa hidrolizada. Las leches hidrolizadas se trataron térmicamente a 100, 110, 120 y 130 °C durante un período de 1 hora y se midió la concentración de glucosa, el grado de pardeamiento y la desnaturalización de proteínas. El grado de dorado en la leche entera varió de 14.4 (100 °C) a 42.6 (130 °C). Para la leche descremada fue de 20.2 (100 °C) a 38.0 (130 °C). La concentración de glucosa en leche entera (47% p/v) y en leche descremada (41% p/v) después del tratamiento térmico (130 °C) mostró una reducción significativa en relación con el control (25 °C). El efecto de la temperatura en la desnaturalización de proteínas en leche entera y descremada en relación con el control (25 °C) fue del 100%. La leche tratada térmicamente con lactosa hidrolizada promovió la desnaturalización de proteínas con un aumento del pardeamiento característico de la reacción de Maillard, lo que afectó la calidad nutricional.
The effect of temperature in protein denaturation and Maillard reaction in whole and skim milk with hydrolyzed lactose was evaluated. Hydrolyzed milk was thermally treated at 100, 110, 120 and 130 °C over a period of 1 hour and glucose concentration, browning degree and protein denaturation were measured. The browning degree in whole milk varied from 14.42 (100 °C) to 42.63 (130 °C) and 20.21 (100 °C) to 38.03 (130 °C) in skim milk. Glucose concentration in whole milk (47% - w/v) and skim milk (41% - w/v) after heat treatment (130 °C) showed a significant reduction in relation to the control (25 °C). The temperature effect in protein denaturation in whole and skim milk in relation to the control (25 °C) was 100%. Thermally treated milk with hydrolyzed lactose promoted protein denaturation with increasing browning characteristic of the Maillard reaction, thus affecting the nutritional quality.
Subject(s)
Protein Denaturation , Temperature , Maillard Reaction , Milk/chemistry , Lactose/chemistry , Thermic Treatment , beta-Galactosidase , Color , Glucose/analysis , HydrolysisABSTRACT
Objective: To investigate some phytochemical constituents and biological activities of twelve samples of Tetrapleura tetraptera (Schumach & Thonn.) taub. and nine samples of Aframomum citratum (C. Pereira) K. Schum fruits collected in the bimodal forest zone (ZONE V), the unimodal forest zone (ZONE IV) and the highlands zone (ZONE III) in Cameroon. Methods: Fresh fruits extracts were obtained by aqueous infusion (100 °C during 15 min) and evaluated by spectrophotometric methods for total polyphenol (TPP), total flavonoids (TFLV) contents and antioxidant (DPPH, total antioxidant capacity by the phosphomolybdenum method, iron reducing power or ferric reducing antioxidant power and inhibition of beta carotene discoloration assays) and anti-inflammatory (inhibitions of protein denaturation and 5-LOX represented by INH.PROT and INH.5- LOX respectively) properties. Principal component analysis was performed. Results: For both species, fruits from ZONE V have the highest TPP, TFLV levels and biological activities. TPP and TFLV content of Aframomum citratum and Tetrapleura tetraptera fruits are positively and significantly (P<0.05) correlated. The biological activities of all extracts (0.25, 2.5, 25, 250 mg/mL) were dosedependent and the extracts have shown strong antioxidant and anti- inflammatory activities, but less than references (ascorbic acid, diclofenac, quercetin, and butylated hydroxytoluene). There was a positive correlation between TPP, TFLV and total antioxidant capacity, ferric reducing antioxidant power, and inhibition of beta carotene discoloration assays, and inverse correlations were observed with the IC
ABSTRACT
Objective: To investigate some phytochemical constituents and biological activities of twelve samples of Tetrapleura tetraptera (Schumach & Thonn.) taub. and nine samples of Aframomum citratum (C. Pereira) K. Schum fruits collected in the bimodal forest zone (ZONE V), the unimodal forest zone (ZONE IV) and the highlands zone (ZONE III) in Cameroon. Methods: Fresh fruits extracts were obtained by aqueous infusion (100 °C during 15 min) and evaluated by spectrophotometric methods for total polyphenol (TPP), total flavonoids (TFLV) contents and antioxidant (DPPH, total antioxidant capacity by the phosphomolybdenum method, iron reducing power or ferric reducing antioxidant power and inhibition of beta carotene discoloration assays) and anti-inflammatory (inhibitions of protein denaturation and 5-LOX represented by INH.PROT and INH.5- LOX respectively) properties. Principal component analysis was performed. Results: For both species, fruits from ZONE V have the highest TPP, TFLV levels and biological activities. TPP and TFLV content of Aframomum citratum and Tetrapleura tetraptera fruits are positively and significantly (P<0.05) correlated. The biological activities of all extracts (0.25, 2.5, 25, 250 mg/mL) were dosedependent and the extracts have shown strong antioxidant and anti- inflammatory activities, but less than references (ascorbic acid, diclofenac, quercetin, and butylated hydroxytoluene). There was a positive correlation between TPP, TFLV and total antioxidant capacity, ferric reducing antioxidant power, and inhibition of beta carotene discoloration assays, and inverse correlations were observed with the IC50 (g/mL) of DPPH, INH.5-LOX and INH. PROT assays for both species. Conclusions: The fruits exhibit variabilities and those from ZONE V for both species are economically and healthcare challenging for herbalists, pharmaceutical firms, scientists and consumers. Indeed, most important extraction yield of bioactive compounds correlated with significant biological activities and the use of less material compared with an implementation in other Agro-ecologic Zones with the same results are noted.
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Objective: The present study was carried out to investigate the in vitro anti-inflammatory activity of syringic acid (SA). Methods: SA was tested for it's in vitro anti-inflammatory activity at different concentrations in protein denaturation, proteinase inhibition and human red blood cell (HRBC) membrane stabilization assay. The reference drugs used were aspirin and diclofenac sodium. Results: SA showed concentration-dependent inhibition of protein denaturation and proteinase activity with a half-maximal inhibitory concentration (IC50) value of 49.38±0.56 µg/ml and 53.73±0.27 µg/ml respectively. Heat-induced haemolysis was inhibited by SA with an IC50 value of 57.13±0.24 µg/ml. SA also inhibited the hypotonicity-induced haemolysis (IC50 value of 53.87±0.72 µg/ml). Conclusion: From the present study, we can conclude that SA possesses appreciable anti-inflammatory effect against denaturation of proteins, proteinase activity, and human red blood membrane stabilization assays. Further studies are required for determining the possible mechanisms behind its anti-inflammatory action.
ABSTRACT
Rheumatoid arthritis is an autoimmune inflammatory disorder, despite the discovery of numerous drugs there is still need to introduce newer, safer and more effective sources of drugs such as medicinal herbs. Present research work was an attempt to appraise the antiarthritic potential of Ribes alpestre Decne in rheumatoid arthritis. In vitro inhibition of protein (bovine serum albumin and egg albumin) denaturation, Human red blood cell membrane stabilization assays along with formaldehyde induced arthritis in rats were commenced in this study. Findings of present investigation demonstrated significant and dose dependent antiarthritic effect of Ribes alpestre. Aqueous ethanolic extract, butanol and aqueous fraction illustrated 95%, 69.233% and 92.840% protection at 6400 ug/mL against bovine serum albumin denaturation respectively. Similarly, plant extract together with butanol and aqueous fractions showed 3653.47%, 1484.03% and 3563.19% inhibition of pathological alteration of egg albumin in that order. Moreover, hydroethanolic extract with butanol and aqueous fraction exhibited 91.29%, 65.73% and 89.62% stabilization against erythrocyte hemolysis at 6400 ug/mL correspondingly. Furthermore, hydroethanolic extract, butanol and aqueous fraction notably 73.49%, 66.42% and 68.87% decreased paw edema at highest dose (200 mg/kg). Similarly aqueous ethanolic extract, butanol and aqueous fraction illustrated 72.38%, 54.90% and 66.33% decrease in paw thickness at 200 mg/kg. Hence results suggested that Ribes alpestre possess antiarthritic potential thus supporting its use as natural remedy in rheumatic conditions.
ABSTRACT
Arthritis is a form of joint disorder that involves inflammation of one or more joints. It is very common condition especially in women and older people. Ayurveda has contributed a lot for the management of arthritic conditions. The plant Bala, identified as Sida cordifolia Linn. is a widely used drug in many of the Ayurvedic formulations especially in those for arthritic conditions. Kashaya (decoction) is one of the commonly prescribed preparations in Ayurveda. Present study was aimed to assess the anti-arthritic activity of Kashaya (decoction) of root of Sida cordifolia Linn. by inhibition of protein denaturation method and Inhibition of proteinase enzyme activity. Kashaya of roots of Bala was prepared as per standard procedure and was used to induce protein denaturation in Bovine serum albumin and to inhibit the activity of proteinase enzyme, trypsin. The absorbance was read by spectrophotometer to evaluate the percentage of inhibition in both the procedures. Each experiment was done in triplicates. The results were compared with standard drug Diclofenac sodium. Sida cordifolia Linn. showed dose dependent inhibitory activity and highest activity was seen in 500µg/ml concentration in both the experiments. The result showed that root of Sida cordifolia Linn. is having anti-arthritic property. Further studies can be carried out with other formulations of Bala like Choorna (powder), Swarasa (juice) etc. to compare their anti-arthritic activity. The study supports the classical use of plant Bala in various formulations in the treatment of arthritis.
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ABSTRACT For optimization of biochemical processes in food and pharmaceutical industries, the evaluation of enzyme inactivation kinetic models is necessary to allow their adequate use. Kinetic studies of thermal inactivation of β-galactosidase from Aspergillus oryzae were conducted in order to critically evaluate mathematical equations presented in the literature. Statistical analysis showed that Weibull model presented the best adequacy to residual enzymatic activity data through the processing time and its kinetic parameters as a function of the temperature, in the range of 58-66 ºC. The investigation suggests the existence of a non-sensitive heat fraction on the enzyme structure, which is relatively stable up to temperatures close to 59 ºC. Thermodynamic parameters were evaluated and showed that such β-galactosidase presents activation energy of 277 kJ mol-1 and that the enzyme inactivation is due to molecular structural changes. Results shown that the enzyme is quite stable for biotechnological applications.
ABSTRACT
Structural characteristics of numerous globular proteins in the denatured state have been reviewed using literature data. Recent more precise experiments show that in contrast to the conventional standpoint, proteins under strongly denaturing conditions do not unfold completely and adopt a random coil state, but contain significant residual ordered structure. These results cast doubt on the basis of the conventional approach representing the process of protein folding as a spontaneous transition of a polypeptide chain from the random coil state to the unique globular structure. The denaturation of proteins is explained in terms of the physical properties of proteins such as stability, conformational change, elasticity, irreversible denaturation, etc. The spontaneous renaturation of some denatured proteins most probably is merely the manifestation of the physical properties (e.g., the elasticity) of the proteins per se, caused by the residual structure present in the denatured state. The pieces of the ordered structure might be the centers of the initiation of renaturation, where the restoration of the initial native conformation of denatured proteins begins. Studies on the denaturation of proteins hardly clarify how the proteins fold into the native conformation during the successive residue-by-residue elongation of the polypeptide chain on the ribosome.
Subject(s)
Elasticity , Protein Conformation , Protein Denaturation , Protein Folding , Proteins/chemistryABSTRACT
Machilus macrantha Nees, Lauraceae, bark is traditionally used in the treatment of asthma, tuberculosis and rheumatoid arthritis. In order to validate, mechanism based anti-inflammatory activity of fractions M. macrantha bark are investigated for first time. Test materials viz. petroleum ether (PE), alkaloidal fraction (CH), acetone extracts (TAN) and mucilage (MM) (250 and 500 mg/kg, p.o.) obtained from M. macrantha bark were tested for membrane stabilizing, anti-nociceptive; anti inflammatory and Freund's complete adjuvant (FCA) induced arthritis activity. Diclofenac sodium and morphine were used as the reference standards in pharmacological assay. Test materials have significantly (p<0.01) inhibited paw edema after Carrageenan and histamine induction at higher doses. Administration of test materials of M. macrantha (250 and 500 mg/kg b.w.) significantly reduced abdominal writhing, formalin nociception, cotton pellet granuloma and vascular permeability in experimental animal. In addition to this, bark of M. macrantha showed chronic anti-rheumatic effect by suppressing the swelling volume, arthritis index, hematological and biochemical parameters (ESR, RA factor, CRP, liver transferase enzyme) in FCA-induced arthritis. It also significantly inhibited protein denaturation, heat-induced haemolysis of RBC and reduction in total leukocyte migration. Bioassay guided fractionation of the pet. ether extract of bark of M. macrantha led to isolation and characterization of β-sitosterol and stigma sterol confirmed by its HPLC, NMR and GC-MS study. In conclusion, extracts of M. macrantha bark can be explored as a therapeutic agent for the treatment of acute and chronic arthritis.
ABSTRACT
RESUMEN En este trabajo se realizó la caracterización del proceso de formación y marcaje de los macroagregados de albúmina (MAA) con 
. Con este fin se efectuaron estudios comparativos para establecer el papel de la desnaturalización en presencia del 
durante la formulación de -Sn-MAA, para ello se utilizaron tres formulaciones. Se realizó un análisis estructural cualitativo de la albúmina sérica humana para describir el sistema a través de un modelo gráfico. Los resultados mostraron diferencias importantes en el comportamiento radioquímico de las tres formulaciones. La formulación de -Sn-MAA (A) mostró un comportamiento superior, con purezas radioquímicas cercanas a 95% en los tiempos estudiados y una disociación inferior al 20% en 24 h.El modelo gráfico permitió explicar, a través de sencillas representaciones, los procesos involucrados en el sistema estudiado, permitiendo una mejor comprensión de este.
ABSTRACT The aim of this paper was to study the formation and radiolabelling of 99m Tcalbumin macroaggregates. Comparatives studies of three formulations to establish the role of denaturalization and in the formulation of -Sn-MAA were carried out. A qualitative structural analysis of human serum albumin was performed in order to give a description of the studied system using a graph model. The results showed important differences in the radiochemical behavior of the three formulations. -Sn-MAA (A) formulation had the best behavior, with radiochemical purity close to 95% and dissociation below 20% after 24 h of being radiolabeled. The graph model explained with simple representations the process involved in the studied system;thus allowing a better knowledge of it.