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1.
Barley was milled into flours with extraction rates between 100 and 69%. The nutritive value of the flours was studied by chemical analyses and in balance trials with growing rats. The concentration of essential nutrients decreased when the extraction rate was lowered. The protein content in the 69% extraction flour was reduced to 82% of that in whole barley. Lysine (g/16 g N) decreased from 3.30 in whole barley to 2.82 in the most refined flour, however, the biological value was not significantly affected by the degree of milling. The content of minerals was reduced to 40% of that in whole barley, but only rats fed refined flours were able to maintain their femur zinc concentration. Factors present in the outer part of the kernel interfere strongly with utilization of zinc; and it appears that phytate is not solely responsible for the adverse effects on zinc utilization. In rats fed whole barley, femur zinc could be maintained and protein utilization improved by zinc supplementation. It could be concluded that unless barley is milled into refined products, or zinc is supplied from external sources, zinc utilization is adversely affected and protein utilization is limited by a poor zinc status.  相似文献   

2.
Low-tannin sorghum was milled into flour with extraction rates between 100 and 64%. The nutritive value of the flours was studied by chemical analyses and in balance experiments with growing rats. The effects of amino acid supplementation was also examined. In general, the content of essential nutrients decreased when the extraction rate was lowered, but the content of fibre, tannins and phytate was also significantly reduced by milling. The digestibility of energy as well as protein was high, but the protein quality was poor, especially in flours of low extraction. Amino acid supplementation improved protein utilization and weight gain considerably. Femur zinc concentration was significantly depressed in the rats fed the amino acid supplemented diets, and sorghum seems to be a poor source of available zinc, in particular when it is highly refined. The poor zinc availability may be attributed to the high content of phytate.  相似文献   

3.
Rye was milled into flours having extraction rates between 100 and 65%. The nutritive value of the various fractions was studied by chemical analyses and in balance trials with rats. The concentration of essential nutrients decreased when the extraction rate was lowered. The lysine content (g/16 g N) was 4.23 in whole rye, but only 3.76 in the 65% extraction flour, and a corresponding reduction in biological value was found. A reduction of 50% or more was observed for several minerals with zinc and phosphorus being most affected. The apparent zinc absorption and retention expressed in absolute values, were significantly higher from the flours of high extraction than from the more refined flours, in spite of a much higher phytate content in whole rye and lightly milled flours. It could be concluded that milling of rye into highly refined flours not only preclude considerable amounts of nutrients from human consumption, but the remaining flours have a much poorer nutritive value than flour made from whole rye.  相似文献   

4.
Protein and energy utilization of rice milling fractions by rats   总被引：1，自引：0，他引：1  
Brown rice (variety IR32), bran, and polish had higher protein content and lysine content in protein than milled rice. Nitrogen balance in growing rats showed that brown rice had lower true digestibility, but similar biological value and NPU as milled rice. Undermilled rice had similar true digestibility, but higher biological value and NPU than milled rice. Bran and polish had lower true digestibility, but higher biological value than brown and milled rice, but polish had higher NPU than bran and the three other milling fractions. The percentage of digestible energy in the rats was lowest for bran.  相似文献   

5.
Rye, wheat, barley, rice, maize and sorghum were milled into more or less refined fractions, and the content of thiamin, riboflavin, vitamin B6, folate, biotin, niacin and tryptophan were determined. Differences in vitamin content between the different cereal grains were rather small. Refining resulted in marked losses of all vitamins studied. On average, 70%–80% of the vitamins were lost during the milling process. The lowest vitamin content was found in highly refined rice, containing only about 5% of the folate and 10% of the niacin present in brown rice. Maize had a low content of tryptophan, and the concentration was greatly reduced by degerming. For the other cereal grains, milling had only a slight effect on tryptophan concentrations.  相似文献   

6.
The protein and energy utilization of brown, undermilled and milled rices (variety IR32) were studied in 5–6 preschool children through diets in which 2/3 of N was from rice and 1/3 from casein or milk powder at 200 or 250 mg N/kg body weight. Brown rice was not significantly inferior to milled rice in terms of nitrogen absorption and retention by the children. Its energy and fat contents were, however, less utilized than those of milled rice. Children on the control casein or milk diets showed better apparent nitrogen absorption than those on the rice-based diets but nitrogen retention of all the diets was similar in all three experiments.  相似文献   

7.
The protein of pigmented brown rices had similar lysine content as that of nonpigmented brown rices, but it was less digestible in rats. Because of higher biological value, only the purple rice, but not red rice, had lower net protein utilization than two nonpigmented rices. Milling, which removed bran-polish and reduced pigment and phenolic content, improved the digestibility of the pigmented rices.  相似文献   

8.
College,Laguna, Philippines.Received 1 ABSTRACT Eight indica and japonica milled rices with low amylose content and low starch gelatinisation temperature were analysed for cooked rice energy and N balance in growing rats and for protein properties. Digestible energy values were similar. Japonica rices Koshihikari and Sasanishiki had higher true digestibility (TD) and net protein utilisation in rats than indica rices IR24 and PR23383-15. Similar results were obtained from in vitro proteolysis. High TD of cooked rices was not significantly correlated with low prolamin content in raw rice and with low waxy gene product (protein bound to starch granule) but was significantly correlated with low cysteine content in protein and with low denatured prolamin content in cooked rice. In two pairs of cooked waxy milled rices, which are devoid of waxy gene product, japonica rice still tended to show higher rat TD and in vitro protein digestibility than indica rice, consistent with lower cysteine content in japonica protein.  相似文献   

9.
Growth of red flour beetleTribolium castaneum (Herbst) larvae with brown or milled rice as the carbohydrate source was faster on diets containing milled rice than on those with brown rice. Larval growth was negatively correlated with amylose content of both brown and milled rice. Among high-amylose (>25%) milled rices, heavier larvae were obtained with rices of low gelatinization temperature (alkali-spreading values 6–7) than with those with higher gelatinization temperature (alkali-spreading values < 6). The differences in larval growth reflected relative digestibility of raw rice starch granules.  相似文献   

10.
针对留胚米产业化生产时出现的留胚率低、碎米率高、食味差等问题,以2011年收获的黑龙江省、吉林省、辽宁省的60个粳稻品种为试验材料,采用SATAKE-TM05试验级碾米机进行留胚米加工试验,筛选留胚率较高的品种,并对留胚率高的品种测定留胚米饭的感官评分和食味综合评分,选出留胚率高且感官评分高的品种;对样品的碾磨品质如糙米率、碾白率及外观品质如糙米白度、精米白度、碎米率、不完善粒率等进行分析检验。结果表明,60个样品中留胚率较高且感官评分较高的品种有6个,即龙稻10号、牡丹江27、牡丹江28、牡丹江30、吉粳95和松粳9;留胚率与碾白率和精米白度相关性较好,与碾白率呈极显著正相关,与精米白度呈极显著负相关,与糙米率呈显著负相关,与不完善粒率呈显著正相关。  相似文献   

11.
Wheat was milled into flours having extraction rates between 100 and 66%. The nutritive value of the various fractions was studied by chemical analyses and in balance trials with rats. The concentration of essential nutrients decreased when the extraction rate was lowered. The lysine content (g/16 g N) e.g. was 2.52 in whole wheat, but only 2.18 in the 66% extraction flour; however, only a slight reduction in biological value was found. The content of minerals was reduced to 30% of that in whole wheat, and the apparent zinc absorption and retention expressed in absolute values, were significantly higher from the flours of high extraction than from the more refined flours, in spite of a much higher phytate content in whole wheat and lightly milled flours. It could be concluded that milling of wheat into highly refined flours not only preclude considerable amounts of nutrients from human consumption, but the remaining flours have a much poorer nutritive value than flour made from whole wheat.  相似文献   

12.
There have been no studies conducted with the objective of investigating the effect of elevated CO2 concentrations ([CO2]) on antioxidants in grains. Therefore, a two-year field experiment was conducted using open-top chambers with two levels of atmospheric CO2 (375 and 550 μmol/mol) to evaluate their effects on rice grain antioxidants. Following exposure to high [CO2], the total phenolic content of all rice milling fractions decreased (3%–18%), with the highest reduction in the brown rice for sinapic acid (167%), and in the white rice for p-hydroxybenzoic acid (100%). The total flavonoid content also decreased under elevated [CO2] in all rice milling fractions (8%–14%), with apigenin (25%) being highly affected in the white rice, and tricin (12%) in the bran. The same trend was found for γ-oryzanol, with decreases of 35%, 32%, 25%, and 2% in the white rice, brown rice, husk, and bran, respectively. In the white and brown rices, tocopherols and tocotrienols were all lower under elevated [CO2], with reductions larger for α-tocotrienol (69%), γ-tocotrienol (46%), and α-tocopherol (38%). Good correlations between antioxidant contents and DPPH radical scavenging capacities indicated that these decreases may be meaningful in the preventive ability of rice against free radical-mediated degenerative diseases.  相似文献   

13.
Among 30 IR varieties, variety had greater effect on thiamine content of brown rice than season. Both season and variety affected riboflavin content. Purple- and red-pericarped Philippines rices had higher riboflavin and crude protein contents than IR rices. Crude oil contents of brown rice and bran-polish of 19 IR rices were significantly affected by variety, but only brown rice oil content was significantly affected by season. Bran-polish of waxy rice IR29 had the highest oil content. Silicon content of hull of 16 IR rices showed significant variation due to variety and season and tended to be higher in the dry season crop. Variety rankings in nutrient composition were not consistent for the two crops. The levels of nutrients of IR rices were within the range of values reported for other rices.  相似文献   

14.
精度对稻米品质的影响   总被引：8，自引：0，他引：8  
 以5个中至长粒形的籼稻品种为材料,研究了碾米精度对稻米品质的影响。结果表明,精度对以精米为对象的各项米质指标的影响十分显著,其中精度与精米的白度、胶稠度、糊化温度及直链淀粉含量等米质指标成正相关,而与精米的整米率、长宽比以及蛋白质含量等米质指标成负相关。  相似文献   

15.
Yellow rice derived from stack-burned unthreshed grains had lower lysine content than white milled rice. Stack burning did not affect energy digestibility in growing rats but decreased true nitrogen digestibility and net protein utilization (NPU). Increasing parboiling time from 20 to 60 min had no adverse effect on energy and protein utilization of parboiled milled rice. Defatting of rice bran-polish with petroleum ether at 50°C had no effect on protein utilization but decreased energy content and utilization. Mechanical dehulling of mung bean (Vigna radiata [L.] Wilczek) reduced fiber content, increased energy and protein digestibility but decreased biological value (BV) and NPU. Toasting and winnowing the bean reduced lysine content, improved digestible energy but decreased BV and NPU. Cooking the bean preparations improved the biological value only in mechanically dehulled bean with resultant higher NPU than that of whole bean.  相似文献   

16.
Different grades of maize flour were produced by dry milling of yellow maize. The chemical composition of wholemeal, three semi-sifted flours and degermed maize was determined, and the nutritional value of the flours were investigated in balance experiments with growing rats. Distinct differences in nutrient and fibre content were found. Amino acid composition was significantly different in the milled fractions, and the content of minerals and phytate in the flours was determined by the extent to which the germ was retained. Phytate: zinc molar ratios ranged from 43 to 2. Weight gain of rats was closely correlated to the concentration of lysine (r=0.99) and tryptophan (r=0.97). Weight gain of rats fed degermed maize was reduced to half of that of rats fed wholemeal. True protein digestibility was high, but protein quality varied widely between the different flour fractions. Energy density of the flours was quite similar. Rats fed wholemeal had the highest intake of zinc and the highest apparent zinc absorption and retention but the lowest femur zinc concentration. Factors present in whole maize may interfere with zinc utilization. The results might indicate an interaction between phytate and fibre. Supplementation of wholemeal with lysine and tryptophan increased the biological value of the protein and the weight gain considerably, but apparent absorption and retention of zinc as well as femur zinc concentration were similar in unsupplemented and supplemented rats. The percentage of zinc absorbed from degermed maize flour was high, but degermed maize has a very low content of minerals and is highly deficient in lysine and tryptophan.  相似文献   

17.
Upland culture of nine varieties at Ivory Coast resulted in decreases in grain weight, brown and milled rice translucency, Chroma meter L* of rough rice, Chroma meter L* and b* of milled rice, milled rice protein, and Amylograph peak viscosity, and in increases in total phenolics of hull and brown rice, and Chroma meter a* of rough, brown, and milled rice of 5 to 8 of the varieties as compared with irrigated culture. Upland culture had no consistent effect on grain resistance to Angoumois grain moth (Sitotraga cerealella).  相似文献   

18.
通过播期试验,对三江平原5个主栽水稻品种的品质性状进行分析。结果表明,播期对整精米率、垩白米率、垩白度、直链淀粉含量、蛋白质含量、食味值均有影响,对糙米率、精米率影响较小。随着播期的推迟,整精米率明显降低,外观品质变劣,且二者呈极显著负相关;直链淀粉含量呈升高趋势,蛋白质含量则呈降低趋势;食味值变化因品种而异。对品质各性状的变异系数进行聚类分析,结果表明,垩白粒率、垩白度受播期影响最大,属于敏感性状;糙米率、精米率、食味值、直链淀粉含量和蛋白质含量受播期影响较小,属于迟钝性状;整精米率受播期影响变异幅度在二者之间。综合而言,早播对5个水稻品种整体品质提升具有正向作用;但从食味值角度出发,早熟品种龙粳31和龙粳46适当晚播可能更有利于口感的改善。  相似文献   

19.
Protein, energy and mineral utilization were examined in growing rats fed cooked, dry legume seeds in combination with polished rice. The legumes tested included 3 varieties of common beans, black, white and brown (Phaseolus vulgaris), lentils (Lens esculenta) and peas (Pisum sativum). The rice:legume mixtures (1:1 N ratio) were the only dietary sources of protein, Zn, Fe and Cu. The rice:black bean mixture was also tested at a 4:1 N ratio. Nutrient utilization was studied by balance trials and mineral utilization was further assessed by tissue analyses. True protein digestibility (TD) and energy digestibility of the rice:legume (1:1) mixtures were high. Biological value (BV) varied only little but was lowest in the rice:lentil mixture. The rice:brown bean mixture had the lowest amount of utilizable protein (UP). The (1:1) rice:legume mixtures did not adversely affect Fe status, as measured by liver Fe content and blood hemoglobin and hematocrit, or Cu status, as measured by liver Cu content and plasma ceruloplasmin. However, femur zinc content indicated a sub-optimal Zn status. Increasing the dietary N from rice in combination with black beans resulted in a substantial improvement of BV, NPU and Zn status of the animals but had a negative effect on UP and Fe status of the rats.  相似文献   

20.
直立与弯曲穗型水稻穗上不同部位籽粒碾磨品质的比较   总被引：2，自引：0，他引：2  
以直立穗型和弯曲穗型水稻材料为对象,研究了穗上不同部位和不同粒位籽粒在碾米品质上的差异。弯曲穗型材料整穗籽粒的糙米率、精米率及整精米率以及粒重均高于直立穗型材料,其中整精米率差异达到显著水平。总体而言,在稻穗的同一部位,两穗型材料一次枝梗籽粒的糙米率、精米率、整精米率和粒重均高于二次枝梗的籽粒;一次枝梗上以第2 或第3粒位籽粒的糙米率、精米率和整精米率较高,第1 粒位籽粒的较低;穗上同一部位二次枝梗籽粒的碾米品质在两穗型材料间的差异大于一次枝梗,而穗型与其排序并无直接关系;两穗型材料籽粒粒重在穗上的分布与排序基本一致。因此,可以通过育种选择来改良直立穗型材料的碾磨品质。  相似文献   

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