Effect of lactic acid and UV irradiation on the cassava and corn starches

In this work, the effect of lactic acid and UV irradiation on the physicochemical and structural characteristics of cassava and corn starches was evaluated. Only the modified cassava starch presented baking expansion capacity. From RVA, reduction of viscosity values, greater internal stability and none set back for modified cassava starch were observed. Modified corn starch did not show any peak viscosity. There were no significant differences in DSC thermal properties of treated and native starches. Amylopectin and amylose molecules from both the modified starches displayed some degradation. Molecular weight of cassava amylopectin was mostly preserved, whereas corn amylopectin was evenly attacked through the granule. Nevertheless, the B long branched chains of cassava amylopectin, with DP~37, were degraded whereas they were unchanged for corn amylopectin.

Amido de mandioca modificado com ácido lático e radiação ultravioleta antes da secagem artificial têm mostrado boa capacidade de expansão, a exemplo da encontrada para o polvilho azedo. Neste trabalho, os efeitos do ácido lático e radiação UV sobre as características físico-químicas e estruturais de amidos de mandioca e milho foram investigados. Apenas o amido de mandioca modificado apresentou capacidade de expansão durante o forneamento. Do RVA, redução dos valores de viscosidade, boa estabilidade interna e nenhuma tendência a retrogradação para este amido modificado foi observado. O amido de milho não apresentou qualquer pico de viscosidade após modificação. Não foram observadas diferenças significativas nas propriedades térmicas, determinadas em DSC, entre os amidos nativos e modificados de ambas as fontes. As moléculas de amilopectina e amilose de ambos os amidos modificados mostraram alguma degradação. O peso molecular da amilopectina do amido de mandioca foi mais preservado, enquanto a amilopectina do amido de milho foi mais atacada em todo o grânulo. As cadeias ramificadas longas da amilopectina de mandioca, com DP~37, foram degradadas, enquanto as de milho mantiveram-se inalteradas.

Photochemical effect of MB on the inactivation of E. coli in blood and biologic functions of blood cells / 第三军医大学学报

Objective To observe the photochemical effect of methylene blue (MB) on the inactivation of E. coli in blood and on biological functions of blood cells. Methods The blood was treated with 15 ?mol/L MB, 40 000 Lux halogen lamp irradiation and 0.35 mmol/l rutin for 10～40 min. The photochemical effect of MB on the inactivation of E.coli in blood was observed. The changes of biologic functions of blood cells were measured by means of RBC membrane binding to poly L lysine, reaction promoted by ATP enzyme and neutrophil phagocytosis tests. Results After treatment for 40 min, the E.coli count in blood decreased by 5 log units. The value of T/E of MB and irradiation of halogen lamp was higher than 1. No obvious changes of the morphology of blood cell were found. The negative electrical charges on membrane of RBC decreased by 11.23%～25.49%. After treatment of the blood for 20～30 min, the activity of Na + K +ATP enzyme of RBC membrane increased by 7.60%～20.07%. When the blood had been treated for 10～20 min, the positive rate of neutrophil phagocytosis enhanced by 9.00%. Conclusion MB photochemical treatment can effectively inactivate E. coli in blood. Under morphology specific condition of effectively inactivated blood bacteria, the shapes and functions of blood cells are not altered, but the RBC adhesion may increase by about 11.23%～25.49%.