Radial distribution of protein by solubility classes in the milled rice kernel

Houston, D. F.; Iwasaki, Tetsuya; Mohammad, Ali; Chen, Lora.

doi:10.1021/jf60159a024

Cited by 22 publications

(8 citation statements)

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“…Albumin content of total protein was higher in the sub-aleurone layer than in the inner endosperm, in agreement with Houston et a/. 29 The proportion of globulin in the protein of sub-aleurone was higher than that in the inner endosperm protein only in the high-protein rice. Based on these results, the crystalline protein bodies and the small spherical protein bodies present only in the sub-aleurone layer'3 together probably have the same aminogram as the common large spherical protein bodies.…”

Section: Proteinsupporting

confidence: 88%

Nutrient content and distribution in milling fractions of rice grain

1979

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Nutrient content and distribution in a low-protein (7.5 %) rice and a high-protein (10.8 %) rice were studied by analysing successive abrasive milling fractions of brown rice. Non-starch constituents decreased from the surface to the centre of the grain in both rices, except that the highest protein fraction in high-protein rice was the subaleurone layer. Starch and amylose contents of starch increased progressively from the surface to the centre of the grain and were lower in high-protein grain. Although this low-protein rice had lower total ash content than the high-protein rice, other samples of the same low-protein rice had comparable ash content to the highprotein rice. Glutelin accounted for 87-93% of milled rice protein. Protein and protein bodies of the sub-aleurone layer and inner endosperm have similar aminograms, and electrophoretic patterns using analytical and SDS-polyacrylamide disc gels.

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Section: Proteinsupporting

confidence: 88%

Nutrient content and distribution in milling fractions of rice grain

1979

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“…However, polishing increased the glutelin concentration in PTT1 and CNT1, increased prolamin concentration in KDML105 and CNT1, but depressed the prolamin concentration in KLG1 and PTT1. Work undertaken by Cagampang et al (1966), Houston et al (1968), and others suggest that storage protein types are not evenly distributed across the grain, with albumin and globulin more abundant in the outer region of the grain (including the aleurone layers) and glutelin increasing in proportion toward the center of the endosperm. By contrast, prolamin is more evenly distributed across the endosperm.…”

Section: Discussionmentioning

confidence: 99%

Nitrogen Fertilizer Increases Seed Protein and Milling Quality of Rice

et al. 2005

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Rice grain breakage during milling is a problem in many parts of Asia. It has been suggested that nitrogen (N) fertilizer can improve the milling quality of rice. Therefore, this study investigates effects of N fertilization on grain N concentration, endosperm storage protein distribution, and milling quality of rice. Four Thai extra long grain commercial rice cultivars (KDML105, KLG1, PTT1, and CNT1) were grown at Chiang Mai University in the wet season of 2001 with 0 or 120 kg of N/ha at flowering. Anatomical sections showed that there was more storage protein accumulated in the lateral regions of polished grain of high N concentration than in grain of low N concentration. Percent (%) unbroken rice was positively correlated with relative abundance of storage protein in the lateral region of the endosperm in all cultivars. Applying N increased head rice N concentration in all cultivars, whereas % unbroken rice was increased in KLG1 and CNT1. KDML105 cultivar, on the other hand, already had high % unbroken rice and more abundant storage protein in the lateral region with the grain of low N concentration. It is hypothesized that high density of storage protein in the lateral region of the endosperm provides resilience and lessens grain breakage during milling. The additional protein may increase hardness in rice grains and thus could make the rice more resistant to breakage during milling. Furthermore, N fertilization may enhance the nutritional quality of rice grain by increasing the glutelin content, which is rich in lysine.

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“…The major storage proteins found in rice are the glutelins, which according to previous studies, account for 80% or more of the total seed protein (Tecson et al, 1971;Juliano, 1972;Villareal and Juliano, 1978). The remaining 20% is divided as follows: albumins, 1 to 5%; globulins, 4 to 15%; and prolamines, 2 to 8% (Houston et al, 1968). It has been demonstrated that the relative contributions of each of the solubility classes of seed proteins can be influenced by genotype, growing conditions, and the analytical methods employed (Sugimoto et al, 1986;Ogawa et al, 1987;Huebner et al, 1990).…”

mentioning

confidence: 98%

Morphometric Analysis of Rice Seed Protein Bodies (Implication for a Significant Contribution of Prolamine to the Total Protein Content of Rice Endosperm)

Krishnan

White

1995

Plant Physiol.

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Electron microscopic observation of thin sections of rice (Oryza safiva L.) endosperm revealed two types of protein bodies (PBs): spherical and irregular-shaped ones. lmmunocytochemical localization studies using antibodies raised against purified glutelins, prolamines, and globulins indicated that the prolamines were localized in the spherical PB, whereas the irregular-shaped PB contained glutelins and globulins. We counted and measured the surface area and the relative volume of 2303 PBs randomly selected from two different developmental stages and from different locations within the endosperm. The ratio of spherical to irregular-shaped PBs was 1 :1.6. Double-label immunogold electron microscopic localization indicated that the globulins represented about 18% of the surface area of the irregular-shaped PBs. Based on our morphometric analysis, we estimate the relative contribution of glutelin as 53%, that of prolamine as 35%, and that of globulin as 12% of the total seed protein.Seed storage proteins can be divided into four classes based on their solubility properties. Albumins are water soluble, globulins are salt soluble, prolamines are soluble in aqueous alcohol solutions, and glutelins are soluble in alkali or acid (Shotwell and Larkins, 1989). Rice (Oryza sativa L.), a staple food crop for millions of people worldwide, has a seed protein content ranging from 5 to 12% (Villareal and Juliano, 1978). The major storage proteins found in rice are the glutelins, which according to previous studies, account for 80% or more of the total seed protein (Tecson et al., 1971;Juliano, 1972;Villareal and Juliano, 1978). The remaining 20% is divided as follows: albumins, 1 to 5%; globulins, 4 to 15%; and prolamines, 2 to 8% (Houston et al., 1968). It has been demonstrated that the relative contributions of each of the solubility classes of seed proteins can be influenced by genotype, growing conditions, and the analytical methods employed (Sugimoto et al., 1986;Ogawa et al., 1987;Huebner et al., 1990).The biosynthesis of rice glutelins and prolamines has been studied in detail by severa1 researchers (Yamagata et , 1982;Luthe, 1983;Wen and Luthe, 1985;Li and Okita, 1993). Glutelins are first synthesized as precursor proteins of 51 to 57 kD. These precursors are then proteolytically processed into a subunits of 34 to 39 kD and fl subunits of 21 to 22 kD. The end products are stored in specialized structures called PBs. A previous electron microscopic study found that glutelins are processed through the Golgi apparatus and are deposited in irregular-shaped PBs (PB type I). Rice prolamines have molecular masses in the 10-to 17-kD range (Mandac and Juliano, 1978;Kim and Okita, 1988;Masumura et al., 1990) and accumulate within distensions of the rough ER (Yamagata et al., 1982;. They are stored in spherical PBs (PB type 11). Recently, the relative contribution of prolamines to the total protein content of rice seeds has been re-examined. Traditionally, prolamines have been extracted with 70% ethanol. However, a study by Sugi...

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Radial distribution of protein by solubility classes in the milled rice kernel

Abstract: Radial distribution of the four solubility classes of protein was determined for eight varieties of milled rice. Five consecutive layers of the kernel, totaling

Cited by 22 publications

References 5 publications

Nutrient content and distribution in milling fractions of rice grain

Nutrient content and distribution in milling fractions of rice grain

Nitrogen Fertilizer Increases Seed Protein and Milling Quality of Rice

Morphometric Analysis of Rice Seed Protein Bodies (Implication for a Significant Contribution of Prolamine to the Total Protein Content of Rice Endosperm)

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