Avaliação da lipase extracelular de Pseudomonas cepacia para purificação em sistema bifásico aquoso

O presente trabalho teve como objetivo a produção de lipase a partir de Pseudomona cepacia por fermentação líquida em biorreator do tipo Bioflo III. As fermentações foram conduzidas a 150 rpm durante 96 horas a 30 °C. Analisou-se a atividade enzimática em diferentes condições de temperatura (20 a 50 °C) e pH (3,0 a 11,0), e obtiveram-se 37 °C e 8,0, as condições ótimas, respectivamente. Para avaliar a estabilidade térmica, a enzima foi incubada em temperaturas de 40, 50 e 60 °C durante 120 minutos. Em uma segunda etapa, foram realizados experimentos preliminares para verificar as condições adequadas de partição da enzima, bem como sua estabilidade e condições ótimas de hidrólise frente às modificações de temperatura e pH. Foram preparadas soluções de PEG 1500, 4000 e 6000 a 50% p/p e soluções tampão fosfato de pHs 6, 7 e 8. Foi feita a caracterização de um sistema bifásico aquoso (SBA) a partir da preparação de soluções estoques de PEG com massas molares de 1500, 4000 e 6000 (50% w/w) e tampão fosfato pH 6,7 e 8,0 (20% w/w de KH2PO4/K2HPO4). Esta caracterização do SBA posteriormente poderá ser utilizada para partição de lipases, bem como de biomoléculas que estejam dentro dessa faixa de pH.

Lipase and esterase: to what extent can this classification be applied accurately?

Enzyme technology is an ever-growing field of knowledge and, in recent years, this technology has raised renewed interest, due to the search for new paradigms in several productive processes. Lipases, esterases and cutinases are enzymes used in a wide range of processes involving synthesis and hydrolysis reactions. The objective of this work was to investigate and compare the specific lipase and esterase activities of five enzymes - four already classified as lipases and one classified as cutinase - in the presence of natural and synthetic substrates. All tested enzymes presented both esterase and lipase specific activities. The highest specific esterase activity was observed for Aspergillus 1068 lipase in natural substrate and for F. oxysporum cutinase in synthetic substrate, while the highest specific lipase activity was observed for Geotrichum sp. lipase in natural substrate and for F. oxysporum cutinase in synthetic substrate. These results display some interface-independent lipolytic activity for all lipases tested. This is in accordance with the rationale that a new and broader definition of lipases may be necessary.

Acid and salt uptake during the marinatig process of Engraulis anchoita fillets influence of the solution: fish ratio and agitation

The aims of this research were to determine the effect of different conditions of the marination stage on the salt and acid uptake, immersion time, and sensorial characteristics during the marinating process of anchovy (Engraulis anchoita). Different solution:fish ratios and the agitation effect during this stage were analyzed. The ratios used were: 0.77:1, 3:1 and 10:1 (with and without agitation). An increase of marinating solution:fish ratio causes a higher speed of acid and salt penetration The product obtained with the 10:1 ratio had a dry and fibrous texture and a slightly salty taste. Salt concentration was statistically significantly lower (p < 0.01) in the samples with agitation. Agitation did not influence the acid uptake, and the salt penetration speed decreased, but rancidity was detected in this product. The ratio 3:1 decreases the marinating time without damaging sensory attributes and can be used in the fish marinating process.

Chemical, biochemical, and microbiological aspects of chitosan quaternary salt as active coating on sliced apples

The biocompatibility of chitosan and chitosan quaternary salt coatings was evaluated for use as edible coatings for sliced apple. Measurement of water loss, color change, and fungal growth appearance were monitored as a function of time. A significant brownish effect was observed on chitosan coated slices, varying greatly from L* = 76.5 and Hue angle = 95.9° (t = 0) to L* = 45.3 and Hue angle = 69.8° (t = 3 days), whilst for TMC coated samples the variation was considerable lower (L* = 74.1; Hue angle = 95.0°) to (L* = 67.0; Hue angle = 83.8°) within the same period. The hydrosoluble derivative N,N,N-trimethylchitosan demonstrated good antifungal activity against P. expansum although highly dependent on the polymer properties such as degree of quaternization. The most efficient formulation was that prepared from derivative having a degree of quaternization of 45%, high solubility, and high viscosity. This formulation restrained fungus spreading up to 30%, while for the control it reached almost 80% of the total assessed surfaces during 7 days of storage.

The kinetics of lipase activity and hydrolytic rancidity of raw, parboiled, and extruded rice bran during storage

The main problem related to rice bran use is that it goes rancid right after its production. The objective of the present study was to apply a mathematical model to evaluate the kinetics of the lipase activity and hydrolytic rancidity of the raw rice bran (RRB), extruded rice bran (ERB), and parboiled rice bran (PRB) stored in low density polyethylene bags at room temperature for 180 days. Extrusion and parboiling were efficient in preventing free fatty acid formationin ERB and PRB.Extrusion reduced the velocity constant of lipase activity as compared to that of RRB while parboiling increased it, and both decreased the lipase activity after equilibrium from 150 days. The extrusion and parboiling treatments increased the velocity constants for the liberation of free fatty acids although the equilibrium was reached with reduced production of free fatty acids in relation to the production of raw rice bran after 150 days ofstorage. Extrusion proved the best treatment under the storage temperature conditions of rice bran from cultivar BRS Primavera.

Salt intake and blood pressure in the University of Asuncion-Paraguay youths: a preliminary study

INTRODUCTION: High salt intake is a major risk factor related to many cardiovascular and renal diseases. World Action on Salt and Health is a newly formed coalition of heath professionals whose goal is to implement changes in salt consumption in their respective countries for the goal of reducing blood pressure. In the same vein, we have decided to study the amount of salt intake in Paraguay to determine if a relationship exists between salt intake and blood pressure. OBJECTIVE: A preliminary study was undertaken to determine salt intake in Paraguay and its relationship with blood pressure, in order to implement a national program to combat hypertension. METHODS: Cross-sectional, observational study of 72 students from various universities in Asuncion (age range 22-30 years). Sodium excretion in 24-hour urine samples and blood pressure were measured. Assuming a steady state, urinary sodium excretion was converted into grams of salt ingested per day. RESULTS: Only 7% of the 72 participants had a salt intake less than the recommended maximum of 5 g/day. Forty-six percent had a blood pressure between 120-139 mmHg and 3% had stage 1 hypertension. There was no significant relationship between sodium excretion and blood pressure. CONCLUSION: Salt intake and blood pressure were found to be significantly elevated in young adults in Paraguay and argues for the importance of instituting a national campaign to reduce salt intake in this society.