25-08-2017, 09:32 PM
The Techniques used in processing of Edible Quality of crude Rice Bran oil in a Small-Scale Industry
The Techniques.docx (Size: 3.33 MB / Downloads: 55)
Abstract of The Project
Solvent extraction, an innovative adaptation of existing crude oil refining technology, is being studied for its potential to upgrade used oils produced by small-scale oil treatment facilities. This report presents the design for a pilot-scale treatment plant using solvent extraction.
This report presents the design and the needed information for a pilot scale solvent treatment plant. Observations and discussion regarding the project and the design assumptions are presented along with the design.
Introduction
Rice oil, also called rice bran oil, has been used extensively in use in Asian countries such as Japan, Korea, China, Taiwan, Thailand and Pakistan. It is the preferred oil in Japan for its subtle flavor and odor. Rice Bran is the brown layer of brown rice. It is the most nutritious part of rice. Rice bran is rich in Vitamin E and Oryzanol, which are natural substances that helps reduce blood cholesterol and fight against free radicals. Rice oil is a minor constituent of rough rice when compared with the carbohydrate and protein content. Two major classes of lipids are present: (1) Those internal within the endosperm and (2) those associated with the bran. The internal lipids contribute to the nutritional, functional, and sensory qualities of rice.
More recently, interest in rice oil escalated with its identification as a “health oil”. Rice oil is a minor constituent of rough rice when compared with the carbohydrate and protein content. Attempts at further development of rice oil production have not been successful because of high capital requirement to construct an oil extraction plant and refining facility and limited availability of stabilized rice bran. Rice bran is the main source of rice oil. The majority of available bran continues to be used for animal feeds without being extracted for the oil. The food industry uses minor quantities of stabilized rice bran as a source of dietary fiber, protein, and desirable oil.
Crude rice bran oil is the raw material of refined rice bran oil manufacturing. In animal feed industry, crude rice bran oil is a better source of energy when compared to animal fats because it is high in metabolizable energy. It contains essential fatty acids for animals and helps reduce heat of digestion. The typical composition of crude rice bran oil is 81.3-84.3% triglycerides, 2-3% diglycerides, 5-6% monoglycerides, 2-3% free fatty acids, 0.3% waxes, 0.8% glycolipids, 1.6% phospholipids, 4% unsaponifiables. In comparison with other vegetable oils, crude rice bran oil tends to contain higher levels of non-triglyceride components, most of which are removed during further refining processes.
ENZYMES IN RICE BRAN
Rice bran contains active enzymes. Germ and the outer layers of the caryopsis have higher enzyme activities. Some enzymes that are present include a-amylase, b-amylase, ascorbic acid oxidase, catalase, cytochrome oxidase, dehydrogenase, deoxyribonuclease, esterase, flavin oxidase, a and b-glycosidase, invertase, lecithinase, lipase, lipoxygenase, pectinase, peroxidase, phosphatase, phytase, proteinase and succinate dehydrogenase.
Particularly lipase, but also lipoxygenase and peroxidase, are probably most important commercially because they affect the keeping quality and shelf life of rice bran. Lipase promotes the hydrolysis of the oil in the bran into glycerol and free fatty acids (FFA). In the intact grain, the lipases are localized in the testa-cross layer of the rice grains while the oil is in the aleurone and subaleurone layers and in the germ. The germ, where 60% of the lipase occurs, is similarly compartmentalized. The rate of FFA formation is highly dependent on environmental conditions. Formation of 5–7% free fatty acids per day has been reported. Up to 70% FFA has been reported for a single month of bran storage. Rice bran oil contains 2–4% FFA at the time of milling. Less than 5% FFA is desirable for producing rice bran oil because high FFA results in high refining losses.