Rice (Oryza sativa) is the most important staple food for a large part of the world's human population, especially in East and South Asia, the Middle East, Latin America, and the West Indies. It provides more than one fifth of the calories consumed worldwide by the human. It is the second leading cereal crop and staple food of half of the world's population. It is grown in at least 114 countries with global production of 645 million tons; share of Asian farmers is about 90% of the total produce. Rice bran, brown outer layer of rice kernel, is mainly composed of pericarp, aleurone, subaleurone layer, and germ. It contains appreciable quantities of nutrients like protein, fat, and dietary fiber. Furthermore, it contains substantial amount of minerals like K, Ca, Mg, and Fe. Presence of antioxidants like tocopherols, tocotrienols, and γ-oryzanol also brighten prospects of rice bran utilization for humans as functional ingredient to mitigate the life-threatening disorders. Moreover, in the developing countries, budding dilemma of food crisis, arising due to lower crop yields and escalating population, needs to utilize each pent of available resources. To provide enough food to all people, there is the holistic approach of using the by-products generated during food processing and preparations. Rice is being processed in well-established industry, but the major apprehension is the utilization of its by-products; rice bran (5-8%) and polishing (2-3%) that are going as waste. Rice processing or milling produces several streams of materials including milled rice, bran, and husk. In developing countries, rice bran is considered as a by-product of the milling process and commonly used in animal feed or discarded as a waste. The potential of producing rice bran at the global level is 29.3 million tons annually, whereas the share of Pakistan is worked out to be 0.5 million tons. In present paper, attempt has been made to highlight the significance of these valuable but neglected ingredients under various headings.

Rice Bran: A Novel Functional Ingredient

Processed rice bran oils (RBOs) – refined chemically (cRBO) and physically (pRBO) – were studied for frying performance compared to sunflower
oil. Their physicochemical differences showed in appearance, color and oryzanol content, partial acylglycerols and unsaponifiable matter. Bhujia was
prepared in sunflower and RBOs and their frying performance measured in the oil from the bhujia. Oils after frying had deeper color (23.9–137.5% increase) and higher peroxide (101.4–274.3% increase) and free fatty acid values (4.7 to +27.3% change) compared to the starting oils, but the RBOs
studied showed lesser changes compared to the control. Oil in the bhujia was slightly lower (7.9%) for a low-oryzanol cRBO while it was slightly higher (+7.0%) for a high-oryzanol pRBO. Both showed mild foaming compared to
the control sunflower oil while retaining oryzanol in the oil and bhujia during frying (when partial acylglycerols caused some foaming). The bhujia retained the RBO’s healthy oryzanol.

Frying Performance Of Processed Rice Bran Oils

Section 701 Manual on Uniform Traffic Control Devices for Streets and Highways, U.S. Department of Transportation, Federal Highway Administration, Washington, D.C. Manual on Uniform Traffic Control Devices for Streets and Highways Part VI, Standards and Guides for Traffic Controls for Street and Highway Construction, Maintenance, Utility, and Incident Management Operations, U.S. Department of Transportation, Federal Highway Administration, Washington, D.C. ADOT Traffic Control Design Guidelines, Arizona Department of Transportation, Traffic Group, Phoenix, AZ Flagging Handbook, American Traffic Safety Services Association, Fredericksburg, VA Quality Standards for Work Zone Traffic Control Devices, American Traffic Safety Services Association, Fredericksburg, VA

Chapter 7 - References

The aim of this study was to establish a method for the determination of hexanal as a lipid oxidation marker in rice. For the sample preparation, ground rice exhibited better sensitivity and reproducibility for the analysis of hexanal than whole rice. A total flow of purge gas of 300 mL at 20 mL/min of purge was sufficient to obtain the necessary sensitivity for the analysis of hexanal in rice. The total time for sample preparation and analysis for individual samples was approximately 15 min. A low incubation temperature of 30°C was chosen, not only to reduce the effect of water, but also to avoid excess lipid oxidation and loss of hexanal during the analysis. The limits of detection and quantification were 3.7 and 5.1 ng/g, respectively. Good linearity was obtained in the range from 5.1-500.0 ng/g. The recoveries of hexanal in rice were greater than 97.0 and 107.0% at the spiked levels of 5 and 50 ng/g, respectively, with relative standard deviations of 3.3 and 6.1%, respectively.

Determination of Hexanal in Rice Using an Automated Dynamic Headspace Sampler Coupled to a Gas Chromatograph–Mass Spectrometer

Rice is one of the most important staple foods on which more than half of the global population depends as a source of their calories. Pakistan being one of the world’s major rice producing countries produces rice not only for its domestic needs but also for export to earn foreign exchange.With the current trends for functional foods and nutraceuticals, growing need exists to explore local rice cultivars for biochemical composition and nutrient specificity to enhance the share of rice in trade market and to benefit consumer’s health.The primary objective of the present research was to characterize selected varieties of rice (Oryza sativa L.) and its by-product (rice bran) for the important nutrients, high value-components and antioxidant attributes.The rice varieties most commonly cultivated in Pakistan were analyzed for the quality- oriented physiochemical and nutritive attributes such as moisture, ash, crude fiber, carbohydrates, lipids, proteins and minerals etc.Proximate analysis revealed that Pakistani varieties, especially, Basmati rice, contain appreciable amounts of important nutrients such as carbohydrates, protein, fat, crude fiber and minerals.Extraction for antioxidant components from rice and rice bran was carried out by employing six solvents; methanol (100%,80%), ethanol (100%,80%) and isopropanol (80%,100%) and two extraction techniques; orbital shaker and sonication-assisted orbital shaker.Overall, best extraction yields of antioxidant components were obtained with 80% isopropanol and 80% methanol using sonication-assisted orbital shaker.The antioxidant activity of the tested varieties of rice and rice bran was assessed using various in vitro antioxidant essays e.g.estimation of total phenolic contents (TPC), 2,2-diphenyl-1- picrylhdrazyl (DPPH) free radical-scavenging capacity, reducing power and ferrous ion-chelating activity.Present study revealed that tested Pakistani rice varieties have considerable potential for total phenolics and radical scavenging activity.The profiles of carbohydrates, fatty acids, sterols, amino acids, tocopherols and γ-oryzanol compounds were studied by using state-of-the-art spectroscopic and chromatographic techniques such as UV/Vis spectrophotometer, HPLC, GC, GC-MS etc., where applicable.Among rice varieties tested sixteen amino acids were detected with glutamic acid, arginine, leucine and aspartic acid as the major components.GC analysis of the fatty acids composition depicted C18:1 and C18:2 as the major fatty acids of rice varieties.GC and GC-MS analysis revealed the presence of β-sitosterol, stigmastenol and campesterol as the main phytosterol components.HPLC analysis of the tocopherols and γ-oryzanol showed the distribution of α- tocopherol (41.2-76.1 mg/kg), γ-tocopherol (20.5-27.5 mg/kg) and δ-tocopherol (6.5-14.2 mg/kg) and 24-methylcycloartenyl ferulate (140.2-183.1 mg/kg), cycloartenyl ferulate (65.5-103.6 mg/kg) and campesteryl ferulate (29.8-45.5 mg/kg) as the principal components.Overall, Basmati Pak, Basmati 198 and Basmati 2000 were found good nutritive varieties in respect of antioxidants potential and valuable nutrients.In view of investigations of valuable phytochemicals and bioactives it is revealed that the rice has great potential for functional food and nutraceuticals applications.Efforts should be made to highlight the nutritive potential/quality of local aromatic rice varieties for enhancing their commercialization at global level.

Characterization of selected varieties of rice (oryza sativa) and its by-product (rice bran) for valuable nutrients and antioxidants

Rice germ oils were extracted from common and dried rice germ , and their oxidative stabilities were evaluated by measuring acid value, peroxide value and fatty acid composition during storage at . The acid values of all lipids were slightly changed during storage, but peroxide values (POV) were greatly dependent on storage temperature. The POVs of the dried germ oil and the refined rice bran oil were 146.2 meq/kg and 15.1 meq/kg, respectively after 31 days storage at . However after 24 days of storage at , the POVs of the dried germ oil and the refined rice bran oil were 151.7 meq/kg oil and 219.6 meq/kg oil, respectively. Major fatty acids were linoleic (39.8%) and oleic acid (34.7%) in rice germ oil, and oleic (40.1%) and linoleic acid (38.1%) in rice bran oil. The major fatty acid compositions were not greatly influenced by drying and storage temperature but linoleic acid decreased about half during storage.

Jong-Ku Chung

Papers

Changes during Storage of Rice Germ Oil and Its Fatty Acid Composition