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1.
High-performance liquid chromatography (HPLC) was used to determine the distribution of phenolic acids in wheat flours produced from five milling extraction rates ranging from 60% to 100% in four cultivars sown in two locations in the 2008–2009 season. Considerable variation was observed in free and bound phenolic acids, and their components in flours with different extraction rates. Most phenolic acids, including the component ferulic, were present in the bound form (94.0%). Ferulic (51.0%) was the predominant phenolic acid in wheat grain, and caffeic (22.8%) and p-coumaric (17.6%) acids were abundant. The phenolic acids and their components were all significantly influenced by effects of cultivar, milling, location, and cultivar × milling interaction, with milling effect being the predominant. The proportions of phenolic compounds varied considerably among milling extractions and cultivars, and their levels depended on both initial grain concentrations and on selection of milling extraction that was incorporated into the final product. The grain phenolic acid concentrations determined ranged from 54 μg g−1 in flour produced at 60% extraction rate to 695 μg g−1 in flour produced at 100% extraction rate, indicating their higher concentrations in bran associated with cell wall materials. Therefore, wholemeal wheat products maximize health benefits and are strongly recommended for use in food processing.  相似文献   

2.
Rice bran is a rich source of valuable nutrients and has potential for high-value applications. Endogenous lipases catalyze the hydrolysis of rice bran oil to free fatty acids, which initiates lipid oxidation. The evaluation of the success of rice bran stabilization processes in terms of the degree of lipid oxidation and shelf-life has so far relied on the measurement of free fatty acid content over a storage period of 3–6 months. In the present study, a photometric and a titrimetric pH-stat method for direct lipase activity measurement immediately after debranning were adapted to rice bran. The photometric method was further applied to determine rice bran lipase/esterase inactivation kinetics, which are useful to optimize stabilization treatments in order to prevent overprocessing and retain maximum level of nutrients. Rice bran was heat-treated in a specialized, hermetically sealable reactor at controlled holding times (5–40 min), temperatures (70–145 °C) and moisture contents (10–20%). Temperature dependency of the lipase/esterase inactivation rate could be described by the Arrhenius equation. Empirical findings on the importance of moisture content for effective rice bran stabilization could be quantified. Furthermore, the results demonstrate the great potential of the method to predict the shelf-life of stabilized rice bran without time-consuming storage tests.  相似文献   

3.
An effect of freeze-milling on processing properties of beta-glucan oat bran has been evaluated. A comparison with existing, patented methods of high molecular weight oat beta-glucan has been carried out. The new method employs raw material pre-treatment with freezing and milling in a hammer mill, resulting in significant reduction of particle size – 89% was between 80 and 50 μm in comparison with initial material when 79% were between 250 and 200 μm. Reduction of particle size also improved some process parameters of extraction technology – 30% improvement in fat removal during first stage of beta-glucan recovery was observed. The achieved pilot plant yield of product containing beta-glucan extraction was 64,03%, purity (ie. beta-glucan content), of achieved product was 84,4% and average molecular weight was about 69,500 g/mol.  相似文献   

4.
Oblongichytrium RT2316-13 synthesizes lipids rich in eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA). The content of these fatty acids in the total lipids depended on growth temperature. Sequencing technology was used in this work to examine the thraustochytrid’s response to a decrease in growth temperature from 15 °C to 5 °C. Around 4% (2944) of the genes were differentially expressed (DE) and only a few of the DE genes (533 upregulated; 206 downregulated) had significant matches to those in the SwissProt database. Most of the annotated DE genes were related to cell membrane composition (fatty acids, sterols, phosphatidylinositol), the membrane enzymes linked to cell energetics, and membrane structure (cytoskeletal proteins and enzymes). In RT2316-13, the synthesis of long-chain polyunsaturated fatty acids occurred through ω3- and ω6-pathways. Enzymes of the alternative pathways (Δ8-desaturase and Δ9-elongase) were also expressed. The upregulation of the genes coding for a Δ5-desaturase and a Δ5-elongase involved in the synthesis of EPA and DHA, explained the enrichment of total lipid with these two long-chain fatty acids at the low temperature. This molecular response has the potential to be used for producing microbial lipids with a fatty acids profile similar to that of fish oils.  相似文献   

5.
Whole rice grain comprising endosperm, embryo (or germ), and bran has potential beneficial health effects in addition to provision of nutrients. The distribution of phenolic acids and anthocyanins in endosperm, embryo, and bran of white, red, and black rice grains was investigated in this study. The total phenolic content (TPC) was highest in the bran, averaging 7.35 mg GAE/g and contributing 60%, 86% and 84% of phenolics in white, red and black rice. The average TPC of the embryo and endosperm were 2.79 and 0.11 mg GAE/g accounting for 17% and 23%, 4% and 10% and 7% and 9% in white, red and black rice, respectively. The antioxidant capacity determined using DPPH and ORAC displayed a trend similar to TPC. Free/conjugated phenolic acids in white, red and black rice bran accounted for 41%, 65% and 85% of total acids. Bound phenolic acids in rice bran accounted for 90% of total acids in whole grain. Cis-p-coumaric was detected in bound form in bran while cis-sinapic acid was detected in the free/conjugated form in embryo and bran. Cyanidin-3-O-glucoside and peonidin-3-O-glucoside were identified mainly in black rice bran as the total anthocyanins. Cyanindin-3-O-rutinoside was also detected in black rice bran.  相似文献   

6.
The structure of the mature buckwheat achene and groat is discussed in relation to milling fractions and nutritional composition. Whole groats contain 55% starch, 12% protein, 4% lipid, 2% soluble carbohydrates, 7% total dietary fiber (TDF), 2% ash, and 18% other components (organic acids, phenolic compounds, tannins, phosphorylated sugars, nucleotides and nucleic acids, unknown compounds). The composition of the milling fractions reflects the relative abundance of seed tissues. Starch is concentrated in the central endosperm. Protein, oil, soluble carbohydrates and minerals are concentrated in the embryo. Commercial «Fancy» flour, a light-coloured flour, is mostly central endosperm and contains 75% starch, 6% protein, 1% lipid, 1% soluble carbohydrates, 3% TDF, 1% ash, and 13% other components. Although the embryo traverses the central endosperm, during milling parts of the embryo separate with the aleurone and seed coat in the bran fraction. Bran, with little central endosperm, contains 18% starch, 36% protein, 11% lipid, 6% soluble carbohydrates, 15% TDF, 7% ash, and 7% other components. Buckwheat bran also is a rich source of TDF and soluble dietary fibre (SDF), particularly bran with hull fragments (40% TDF of which 25% is SDF), while bran without hull fragments has 16% TDF of which 75% is SDF.  相似文献   

7.
This study determined the lignan content of seven varieties of triticale grain and compared these values with wheat and rye grain, with triticale milling fractions (bran, shorts, and refined flour), and triticale products (sprouted grain, malt, fermented bread dough, baked dough, dried pasta and cooked pasta). Acid hydrolysis and enzymatic hydrolysis were used to release the lignans in extracts. We carried out qualitative and quantitative analysis of secoisolariciresinol, matairesinol, lariciresinol, syringaresinol, and pinoresinol levels using an Acquity UPLC liquid chromatograph with photodiode and mass Acquity TQD detectors. The most abundant lignan in all samples was syringaresinol, which made up 80% of all lignans. The lignan content of triticale grain varied from 392 to 792 μg·100gd·m−1 (acid hydrolysis) and from 685 to 1189 μg·100gd·m−1(enzymatic hydrolysis), depending on the variety. The lignan levels in triticale bran were almost three times those found in the grain; in flour, there was one fifth or even one tenth as much, whereas the shorts had similar levels as the grain. After three days of germination, the amount of lignans in the triticale grain increased by 17%–32%. A greater increase in lignan content (by factors of 1.4 and 2.3) was found in triticale after extrusion cooking. Fermentation led to lignan concentrations increasing slightly (2–14%), but this was then reduced in the baking process. Extracts from dry pasta contained similar or lower amounts than did the raw material, but the concentration was higher in cooked pasta (14%–47%). The enzymatic hydrolyzed extracts contained on average 36% higher lignan content than did the acid hydrolyzed samples.  相似文献   

8.
The enrichment of liquid food matrix with wheat bran has not yet been explored. This study investigated the impact of disintegrating wheat bran preparations on their stability at high moisture content. Three wheat bran preparations – standard bran, peeled bran and aleurone rich fraction – were modified by dry grinding, enzymatic degradation, wet grinding and microfluidization. The sedimentation of processed preparations was evaluated in water solution and related to their physical structure, solubilized compounds and suspension viscosity. In dry ground preparations mixed in water (5% w/w), most of the particles sedimented already in 5 min. Wet grinding disintegrated the physical structure of bran preparations (d50 = 10–16 μm), causing improvement of particle stability due to reduction of gravitational sedimentation. Enzymatic treatment with xylanase efficiently increased the total solubility of the bran preparations (from 18–24% to 40–50%), but the higher solubility was not related to the better stability of particles. Microfluidization of peeled bran and aleurone increased the viscosity and stability of dispersions. The higher viscosity of the microfluidized dispersions was likely correlated with the better homogenisation of the particles, and also with the modified microstructure of treated bran preparations. Disintegrated wheat bran preparations showed high potential for beverage applications.  相似文献   

9.
Lipids play an important role in determining the quality of wheat flour and its suitability for different bakery products. The lipid content and fatty acid composition in various flour streams showed a wide variation. The free lipid content varied from 0·1 to 1·9% (db) and bound lipid content from 0·2 to 2·1% (db) in different flour streams. The amount of bound lipid was more in reduction streams. The palmitic and linoleic acids were the predominant fatty acids present in free and bound lipids. These fatty acids were found to be higher in the «III» «Break coarse», «IV» «Break filter», «III» «Break fine», «1st» and «4th» «middling». The studies showed that the reduction passage flours had more of bound lipids indicating the presence of polar lipids.  相似文献   

10.
Raw rice bran was treated with or without visible light exposure at room temperature or stored at 40 °C in the dark for 10 days and rice bran oil (RBO) was recovered from each rice bran. Headspace oxygen content from rice bran and conjugated dienoic acid (CDA) value, acid value, content of γ-oryzanol, and fluorescence intensity in RBO were analyzed to determine the effects of visible light on the oxidative stability in rice bran. Headspace oxygen content in visible light irradiated rice bran (RBL) decreased by 12.8% for 10 days while those in the dark (RBD) and stored at 40 °C (RBT) decreased by 5.87 and 5.35%, respectively, implying visible light irradiation accelerates the consumption of oxygen. CDA values in RBO from RBL were significantly higher than those in RBO from RBD and RBT (p < 0.05). However, acid values in RBO were not significantly different among samples (p > 0.05). Both γ-oryzanol content and fluorescence intensity in RBO from RBL were significantly lower than those in RBO from RBD and RBT (p < 0.05). Fluorescence intensity, which is related to the content of chlorophylls, decreased in samples under light only, implying that chlorophyll photosensitization may play important roles in the acceleration of lipid oxidation in rice bran.  相似文献   

11.
A method using methanolic sulphuric acid as transmethylating reagent was developed for determining the fatty acid composition of lipids of oats. The method was optimised for reaction conditions and applied to the determination of the fatty acid composition of lipids of a number of varieties of Australian oats grown in several locations. Thirteen fatty acids were detected with oleic, linoleic and palmitic acids comprising more than 95% of the total fatty acids. Total lipid content of the oats was positively related to the proportion of stearic (r=0·32) and oleic (r=0·81) acids and negatively correlated with the proportion of palmitic (r=−0·64), linoleic (r=−0·39) and linolenic (r=−0·65) acids. Significant positive correlations were found between total lipid content and absolute content of the major fatty acids (r=0·670·98), except for linolenic acid (r=0·12). Environment had significant effects on fatty acid composition, but variety was the controlling factor. The broad sense heritability estimated from individual plot ranged from 69 to 73% and that from the average of three replications and eight locations ranged from 94 to 98% for the major fatty acids. It is possible to improve fatty acid composition of oats by breeding procedures.  相似文献   

12.
Pearl millet was decorticated to obtain a bran rich and endosperm rich fraction. The two fractions were soaked in solutions with varying pH. Pearl millet grains were germinated and steamed followed by decortication to obtain two fractions. It was observed that bran rich fractions contained high concentrations of iron, zinc, polyphenols, phytic acid, fibre and flavonoids. Soaking for short duration of 3 h did not result in major mineral losses but decreased the inhibitory factors which depended on the pH. Alkaline soaking decreased flavonoid content by 62.7% in the endosperm rich fraction, while acidic soaking decreased phytic acid content to the maximum in the bran rich fraction. Combination of treatments like germination and heat decreased the phytate content to the maximum in the endosperm rich fraction. Acidic conditions improved zinc bioaccessibility in the bran rich fraction (35%) and iron bioaccessibility (2.5%) in the endosperm rich fraction. Bran rich fraction from germinated grain also had enhanced bioaccessibility of both the minerals but comparatively lesser when compared to soaking under acidic conditions. Soaking the grain components under slightly less than neutral conditions also decreased some of the inhibitory factors and improved the zinc bioaccessibility to some extent in the bran rich fraction.  相似文献   

13.
The lipid content and fatty acid profiles of four lesser known tropical seeds,Piper guineense, Chrysophyllum albidum, Garcinia kola andDennettia tripetala, were determined. The total lipid content (g/kg dry weight) ranged between 31.8 and 68.9. The ranges of values for neutral lipids, triacylglycerol of neutral lipids, glycolipids and phospholipids were 17.3–58.0, 15.0–49.6, 3.0–7.2 and 3.7–11.2, respectively. The fatty acid profiles showed variation among different seeds. All the seeds contained substantial amounts of unsaturated fatty acids. Oleic and linoleic acids were the most abundant fatty acids.Dennettia tripetala andPiper guineense also contained moderate amounts of linolenic acid.  相似文献   

14.
To reveal the characteristic chemicals of walnuts from different origins, we analyzed fatty acid composition,tocopherols, phytosterols and total phenolic content(TPC) of walnuts from three main producing regions in China. The results showed that walnuts were rich in polyunsaturated fatty acids, and the ratio of ω-6 to ω-3 fatty acids was close to the recommendation of Chinese Nutrition Society. Moreover, walnuts contain high contents of tocopherols(331.20–414.71 mg/kg), phytosterols(97.17–110.35...  相似文献   

15.
Conventional barley has an excellent nutritional value, but a lower content of lipids than oat. Nevertheless, barley lipids deserve a focused interest due to their fatty acid composition and their vitamin E composition. In this study, 1H HR MAS NMR was used to monitor the deposition of lipids during grain filling of conventional barley, and of two barley endosperm mutants with increased lipid content. The lipids in the mutants are primarily synthesized between days 9 and 13, whereas the lipid biosynthesis in the conventional barley took place ten days later. GC analysis on barley flour lipids showed that the mutants and the control exhibit comparable relative levels of the major fatty acids: C16:0, C18:1 and C18:2 despite the higher content of lipids in the mutants. Differences in the minor fatty acid composition between control and mutants were also observed. The degree of unsaturation was found to be increasing during grain filling for both conventional barley and the two mutants.  相似文献   

16.
The three major botanical components (starchy endosperm, aleurone layer and pericarp) of eight durum wheat samples exhibited significantly different compositions and concentrations in phenolic acids. The starchy endosperm, the aleurone layer and the pericarp were respectively characterised by a low content in ferulic acid (FA), a high content intrans -sinapic acid (t -SA), and a high content in ferulic acid dehydrodimers (DHD). These three chemical markers can be exploited to differentiate the three grain botanical parts within milling fractions and to evaluate the milling efficiency, particularly the separation between bran and endosperm. The histological dissociation of the wheat grain generated by the milling process can be investigated further into details using the three phenolic acids markers. A separability index (S i) was proposed in order to quantify the ease of dissociation of endosperm from bran. Differences in S i values between wheat varieties grown under various agricultural conditions demonstrated the relevant variability of this character. The structural and molecular factors implied in the control of tissue dissociation are discussed in details.  相似文献   

17.
Using broken rice and rice bran as raw material, texturized rice (TR) was prepared by Improved Extrusion Cooking Technology (IECT) in which gelatinization is formed by means of low temperature and high pressure. The expansion of extrudate was hardly changed so that TR showed similar texture properties and shape with polished rices. The effect of rice bran addition (0% and 4%) and IECT conditions, including feed moisture content (26.6-33.4%), screw speed (20.1-32.6 rpm) and shearing compression metering zone temperature (SCMT, 69.8-120.2 °C) on the physicochemical, texture and nutritional characteristics of TR, were investigated by response surface methodology using Central Composite Design. When the bran addition was 4%, feed moisture content was 30%, screw speed was 26.6 rpm, SCMT was 95 °C, prepared TR contained 16.61 ± 0.02% of total dietary fiber, 9.40 ± 0.04% of protein, 3.68 ± 0.03% of fat, 2.42 ± 0.02 μg/g of thiamin, 0.52 ± 0.01 μg/g of riboflavin and 16.07 ± 0.12 mg/100 g of γ-oryzanol (dry matter content). The content increase of TDF for TR was 15.81% and the content increases of nutrients for thiamin, riboflavin, and γ-oryzanol were 1.39 μg/g, 0.24 μg/g, and 8.99 mg/g dry matter content, respectively, compared with those of polished rice.  相似文献   

18.
Effects of lipid removal on the fine milling and air classification processing of oats were studied. Lipid removal by supercritical carbon dioxide (SC-CO2) extraction enabled concentration of the main components of oats - starch, protein, lipids and cell walls - into specific fractions. Using defatted oats as raw material, the highest β-glucan concentration of the cell wall-enriched fraction was 33.9% as compared to 17.1% without lipid removal. This was probably due to more efficient milling yielding smaller particles, and release of starchy material from cellular structures during milling of defatted oats, resulting in better classification. The removal of lipids also enabled separation of an oat protein concentrate with a protein concentration of 73.0% and a mass yield of 5.0%. A trial with 2310 kg of oat groats showed that the process based on defatting and dry fractionation was also industrially applicable.  相似文献   

19.
The fatty acid profiles and tocopherol and phytosterol contents of crude oils of cress (Lepidium sativum L.) and field pennycress (Thlaspi arvense L.) are reported, along with yields from the corresponding seeds. The physical properties of these oils were also determined, which included oxidative stability, kinematic viscosity, viscosity index, low temperature fluidity, specific gravity, acid value, lubricity, and iodine value. The oil content of dried cress and field pennycress seeds was 22.7 and 29.0 wt%, respectively. The primary fatty acids found in cress oil were oleic (30.6 wt%) and linolenic acids (29.3 wt%), whereas field pennycress oil was principally composed of erucic (32.8 wt%) and linoleic (22.4 wt%) acids. Cress oil contained high concentrations of γ- (1422 ppm) and δ- (356 ppm) tocopherols, whereas α-tocopherol (714 ppm) was the primary tocopherol discovered in field pennycress oil. The overall tocopherol concentrations of cress and field pennycress oils were 1799 and 851 ppm, respectively. The primary phytosterols elucidated in cress and field pennycress oils were sitosterol and campesterol, with avenasterol also present in significant quantity in cress oil. The total phytosterol concentration in cress oil (14.41 mg/g) was greater than that in field pennycress (8.55 mg/g) oil. Field pennycress oil exhibited excellent low temperature fluidity, whereas cress oil was more stable to oxidation and over a range of temperatures displayed lower kinematic viscosities as well as a higher viscosity index. The acid and iodine values of field pennycress oil were lower than those for cress oil, but both oils had excellent lubrication properties.  相似文献   

20.
Superheated steam (SS) at 170 °C for 5 min was used to inactivate lipase of common buckwheat grains in this study, which effectively retarded lipid hydrolytic rancidity and maintained lipid nutrition of common buckwheat. Higher stabilities based on lower free fatty acid accumulation and lipase activity were observed in SS-treated buckwheat samples during storage. Meanwhile, SS could suppress oxidation of unsaturated fatty acids (UFA) in buckwheat, significantly retard the increase of saturated fatty acids and the decrease of polyunsaturated fatty acids during storage. Moreover, the lipidomics profile results indicated that SS processing could retard the increased hydrolysis and oxidation of sulfoquinovosyl diacylglycerol, phosphatidylethanolamine, phosphatidylserine and lysophosphatidic acid during storage, while regulate the content of galactolipids. Thus, SS processing could effectively inactivate lipase, suppress UFA oxidation, change glycerolipids and glycerophospholipids subclass metabolism, and consequently retard hydrolytic rancidity and the loss of lipid nutrition in buckwheat during storage. SS processing was proved to effectively protect the quality of buckwheat during storage for the first time.  相似文献   

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