Effects of Liquid Nitrogen Deep Freezing Treatment on Rice Starch Properties

Abstract

Rice is the most important food crop in Thailand but has low value as commercial uses of rice are limited. Changes in rice starch after deep freezing with liquid nitrogen are studied. Results show that deep freezing affects the physicochemical properties of rice starch depending on amylose and moisture contents. Deep freezing cause alterations in particle size, swelling power, and acid hydrolysis. Pasting properties analyzed by a rapid visco analyzer (RVA) indicate that after freezing, samples are more stable to shear than native rice. Thermal properties determine by differential scanning calorimetry show that gelatinization enthalpy is lower in deep frozen samples. Scanning electron microscopy shows that starch granules are affected by deep freezing, while the sample surface exhibits merging between granules that contain large amounts of water.

Curcumin assisted green synthesis of silver and zinc oxide nanostructures and their antibacterial activity against some clinical pathogenic multi-drug resistant bacteria

“…In the present study, the extraction process of curcumin from the Curcuma longa plant was carried out by following the previously reported extraction protocol by Pothitirat and Gritsanapan 35 with a bit of modification. 36,37 Briefly, about 100 g of Curcuma longa powder was mixed in 1000 ml of absolute ethanol under vigorous stirring and reflux at 60C for 24 h. Then the mixture was filtered using Whatman filter paper. The net yield of curcumin extracted from Curcuma longa powder was calculated by obtaining the precipitate from the extraction process was dried at room temperature and then weighted to obtain the yield of extracted curcumin as follows;Extracted curcumin (g) = the initial used Curcuma longa – the obtained precipitate powder…”