Rice: Parboiling and Milling Properties

Parboiling is a hydrothermal processing technique during rice has to pass through many stages which alter the physicochemical properties and nutritional profile of grain. Different parboiling techniques have been developed for preparation and industrialization of rice. During parboiling process, starch granules are gelatinized and retrograded as a result various changes occur in rice kernel, which affects its quality parameters. Parboiling has marked influence on organoleptic properties, improved the strength and nutritional profile of grain. Parboiling treatment principally brings the characteristic change in rice grain such as milling, cooking, storage and eating qualities. Milling is an important unit operation for removing the husk and bran from the rough rice. Milling significantly affects the cooking and nutritional properties of rice. The important parameters focussed during milling are the head rice yield and kernel hardness. Milling technology is therefore geared to obtain maximum outturn of milled rice and to reduce breakage.

Optimization of Hydroxyropylation Conditions and Property of Acid-Modified Hydroxypropyl Pueraria Lobata Starch

In order to improve the property of pueraria lobata starch, and enlarge application fields of pueraria lobata starch, this study involved in the optimization of determining parameters in hydroxyropylation conditions and the property of acid-modified hydroxypropyl pueraria lobata starch with low substitution degree (DS).Characterizations were carried out by analyzing the spectrum of the thermograms of differential scanning calorimetry (DSC) and thermal gravimetric analysis (TGA). The fludity was used for characterizing the degree of acid hydrolysis. The substitution degree was measured by the spectrophotometric method. The optimized hydroxyropylation conditions were as follows: reaction temperature 40°C, reaction time 18h, amount of sodium hydroxide 1.2%, amount of anhydrous sodium sulfate 12%, respectively. The properties such as the transparency, freeze-thaw stability, blue value, swelling power, retrogradation, acid and alkali resistance of acid-modified hydroxypropyl pueraria lobata starch were compared with those of pueraria lobata starch and acid-modified pueraria lobata starch. It was shown that acid hydrolysis and hydroxyropylation increased the decomposition temperature, but reduced the enthalpy value from the thermal analysis.