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1.
Rice grains were obtained from two Chinese provinces (Hubei and Guangxi) and then their rice bran was abraded into four equal fractions by weight from outside to inside. The component distributions in these four fractions were then investigated. The contents of total lipid-soluble antioxidant showed no significant difference between rice bran from the Hubei province and the Guangxi province. But the content of total water-soluble antioxidant was 1690.20 ± 86.40 mg kg−1 for rice bran from the Hubei province, significantly higher than those from the Guangxi province (1014.67 ± 71.09 mg kg−1). Obvious differences between four rice bran fractions or two provinces were proved by principal component analysis (PCA). Lipase activities decreased significantly from outer fractions to inner fractions, and lipids mainly distributed in three outer fractions. The essential element contents decreased significantly, but a main heavy metal element (Pb) in cereal increased significantly to 0.36 mg kg−1 from outer fractions to inner fractions, which was just slightly below the upper limit of Chinese Standard (0.40 mg kg−1). Although protein contents had no significant difference in four fractions, the amino acid compositions were quite different. In summary, different fractions of rice bran had different compositions, which could provide guidance for the classified processing of rice bran.  相似文献   

2.
为了解四川麸醋发酵过程中有机酸及游离氨基酸含量的变化规律,采用高效液相色谱和氨基酸自动分析仪对发酵过程中7种有机酸及17种游离氨基酸含量进行测定。结果表明,四川麸醋发酵过程中含量最高的2种有机酸为乙酸和乳酸,随着发酵的进行,其含量显著增加;草酸、柠檬酸、酒石酸、苹果酸、琥珀酸含量较低,在发酵过程中含量略有变化。游离氨基酸含量随着发酵的进行呈增加趋势,从发酵初期668mg/100g增至1 470 mg/100g,其中天门冬氨酸、丝氨酸、谷氨酸、甘氨酸、丙氨酸、缬氨酸、组氨酸、异亮氨酸、酪氨酸、脯氨酸对四川麸醋风味形成具有较大的贡献。  相似文献   

3.
Changes in the proximate composition of developing seeds of sandalwood (Santalum spicatum R Br) were quantified. The developing fruits were collected regularly over a period of 5 months commencing 14 days after flower opening. Rapid deposition of seed lipid began at about 91 days after flowering (DAF) at a level of 4 g kg−1 and continued to about 396 g kg−1 at 147 DAF. Protein and ash contents displayed similar trends to that of lipid with a corresponding decrease in moisture content. Fatty acid analysis of the seed oil demonstrated marked changes in composition during seed development. In particular, major increases in oleic and ximenynic acids were noted with corresponding decreases in the other fatty acids. © 1997 SCI.  相似文献   

4.
The influence of processing on soya bean lipids during kinema production was studied. The crude lipid (CL), free fatty acid (FFA) and phytosterol contents of raw beans were 121 g, 6·9 g and 0·8 g kg−1 dry matter, respectively. After soaking and cooking the moisture content of beans increased significantly from 121 to 749 g kg−1, whilst the lipid contents were unchanged. During a 2 day fermentation at 37°C, the lipid contents increased significantly as indicated by capillary column gas chromatography (GC) analysis of petroleum ether extracts of lyophilised samples of unfermented and fermented beans. The fatty acids, palmitic (C16:0), stearic (C18:0), oleic (C18:1), linoleic (C18:2), linolenic (C18:3) and arachidic (C20:0) acids were identified. The major fatty acid present in all samples was the essential fatty acid, linoleic acid. All of the aforementioned fatty acids (except arachidic) were liberated during fermentation by microbial lipases, yielding approximately the same proportion of fatty acids found in unfermented beans. The unsaponifiable soya bean lipids identified by GC were campesterol, stigmasterol and β-sitosterol (ratio 1·2:1:3·4). Levels of these increased during fermentation by 50–61%, but remained in approximately the same proportions.  相似文献   

5.
Common mushrooms, Agaricus bisporus (Lange) Imbach, were stored at 12 °C for 12 days and composition changes were examined during post-harvest storage. The contents of total sugars, mannitol and fructose decreased steadily during storage, whereas the content of other reducing sugars, excluding fructose, remained constant. The content of total free amino acids increased from 77.92 at day 0 to 140.57 g kg−1 at day 6, and then slightly increased to 151.65 g kg−1 at day 12. The contents of nine amino acids increased over time, of these glutamic acid was the most significant. The content of monosodium glutamate-like components increased from 22.67 at day 0 to 47.12 g kg−1 at day 12. However, the contents of sweet and bitter components increased comparably from 24.08 and 24.17 at day 0 to 47.15 and 50.75 g kg−1 at day 12, respectively. Total 5′-nucleotide content peaked at day 3. The contents of three flavour 5-nucleotides were high at days 3 and 6. © 1999 Society of Chemical Industry  相似文献   

6.
Using cannulated pigs and a standardised in vitro fermentation system the effect of diet and non‐starch polysaccharides (NSP) on the amount of energy available from microbial fermentation in the large intestine could be predicted. The available energy was calculated from the amounts of short‐chain fatty acids (SCFA) produced. Three diets were investigated: a low fibre diet based essentially on wheat flour (56 g NSP kg−1 feed) and two high fibre diets with added oat bran (93 g NSP kg−1 feed) or wheat bran (102 g NSP kg−1 feed). Colonic fermentation was estimated by in vitro fermentation of freeze‐dried ileal effluent collected from cannulated pigs. The in vitro fermentation method was optimised to use 10 g ileum content litre−1 incubated at pH 6.0 in a fermentor containing faecal slurry consisting of anaerobic mineral salts medium and 50 g litre −1 faeces from pigs fed the same diets as the cannulated pigs. The results demonstrate that it is very important to compensate for the faecal SCFA contribution when calculating the amount of SCFA produced from ileal digesta during in vitro fermentation. The amount of NSP digested in vitro was compared with data obtained from in vivo studies and there was a good agreement between in vivo and in vitro data. We concluded that the integrated in vivoin vitro method is a valuable technique to estimate the effect of diet and NSP on the amount of SCFA produced in the large intestine and when fed the three diets the microbial fermentation in the large intestine provided between 2.4–6.4% of the total available energy. © 1999 Society of Chemical Industry  相似文献   

7.
BACKGROUND: Camelina sativa cake (CSC), a rich source of unsaturated fatty acids, in the case of ruminants, may improve the energy value of a diet and also increase the unsaturated fatty acid content in milk. Effects of basal diet (control), basal diet plus 30 g kg−1 of CSC in dietary dry matter (DM), basal diet plus 60 g kg−1 of CSC in dietary dry matter on milk production and the fatty acid composition of ewe's milk with particular emphasis on the monoenes and conjugated isomers of linoleic acid content were examined. RESULTS: Elevated concentration of total monounsaturated fatty acids, the effect of an increase in monounsaturated fatty acids in the trans configuration, as well as the increased content of total polyunsaturated fatty acids, resulted from CSC supplementation. Total saturated fatty acid concentration was decreased. CONCLUSION: Milk from CSC‐supplemented ewes was characterized by increased levels of beneficial nutritional factors, including mono‐ and n‐3 polyunsaturated fatty acids, and was also by lower atherogenic and thrombogenic indices. Taking into consideration all the obtained results and recommended fat concentrations in a daily ruminant ration, we recommend supplementing a dairy ewe's diet with 30 g kg−1 DM of CSC cake in practice. Copyright © 2011 Society of Chemical Industry  相似文献   

8.
The enrichment of cassava protein content using solid substrate fermentation was studied on both laboratory and on-farm scales using Aspergillus niger as a starter. The effects of cassava particle size and of various nitrogen source ratios and mixing methods were investigated. Ammonium sulphate and urea as sources at respective levels of addition (g N kg−1 substrate) of 10:10, 20:10 and 20:20 were used in combination with cassava alone and cassava mixed with rice bran and soya bean each having mixing levels of 50, 100 and 150 g kg−1. The mixture was fermented for 84 h at 35°C and 90–95% RH on the laboratory scale and 29–31°C and 95–99% RH at the on-farm scale. The results indicated that cube sizes ranging from 0.3 to 0.5 cm3 gave good mycelial growth. Pure cassava alone at the 10:10 nitrogen addition level produced the highest protein yield of about 145 g kg−1. The on-farm technique yielded higher protein enrichment compared with laboratory experiments. Cassava alone yielded 230 g kg−1 protein while cassava with rice bran and cassava with soya bean each produced 210 g kg−1 protein.  相似文献   

9.
The effect of a previous combined treatment (CO2-enriched modified atmosphere packaging, MAP and high-pressure processing, HPP, 150 MPa/5 min) on lipid stability of refrigerated (10 days/4 °C) salmon (Oncorhynchus kisutch) was studied. The following processing conditions were compared: B-0 (fish without MAP or HPP), B-1 (fish packaged under MAP and without HPP), B-2 (fish subjected to HPP without MAP) and B-3 (fish subjected to MAP and HPP). An inhibitory effect (P < 0.05) on lipid hydrolysis and oxidation was obtained by the presence of CO2 in the packaging medium; values detected at day 10 for B-0 and B-1 fish were 80.72 and 49.61 (g free fatty acids, FFA, kg−1 lipids), 6.14 and 2.81 (meq active oxygen kg−1 lipids; peroxide value), 5.05 and 3.10 (mg malondialdehyde kg−1 muscle), and 5.56 and 2.70 (fluorescence ratio), respectively. Furthermore, inhibition of lipid damage was observed for HPP alone; values detected at day 10 for B-2 fish were 76.24 (g FFA kg−1 lipids) and 5.28 (meq active oxygen kg−1 lipids). The lowest average values for lipid hydrolysis and oxidation were obtained in samples corresponding to the combined treatment (B-3 batch), differences being significant (P < 0.05) at day 10 for FFA (41.43 g kg−1 lipids), peroxide (1.84 meq kg−1 lipids) and fluorescence (2.50) values.  相似文献   

10.
BACKGROUND: Oil production from rice bran, an undervalued by‐product of rice milling, produces defatted rice bran (DRB) as a waste material. Although it is considered a less valuable product, DRB still contains useful substances such as phenolic compounds with antioxidant, UV‐B‐protecting and anti‐tumour activities. In this study the phenolic acids in DRB were extracted with subcritical water at temperatures of 125, 150, 175 and 200 °C. RESULTS: Analysis of total phenolics using Folin–Ciocalteu reagent showed about 2–20 g gallic acid equivalent kg?1 bran in the extracts. High‐performance liquid chromatography analysis showed low contents of phenolic acids (about 0.4–2 g kg?1 bran). Ferulic, p‐coumaric, gallic and caffeic acids were the major phenolic acids identified in the extracts. Thermal analysis of the phenolic acids was also done. The thermogravimetric curves showed that p‐coumaric, caffeic and ferulic acids started to decompose at about 170 °C, while gallic acid did not start to decompose until about 200 °C. CONCLUSION: Subcritical water can be used to hydrolyse rice bran and release phenolic compounds, but the high temperatures used in the extraction can also cause the decomposition of phenolic acids. Copyright © 2010 Society of Chemical Industry  相似文献   

11.
In a non-conventional lab-scale fermentation of cocoa beans using probiotic microorganisms and substituting the cocoa pulp for fruit pulp, physicochemical, microbiological and quality parameters were investigated. Two hundred grams of beans were fermented in a controlled environmental chamber (temperature ramp rate of 25°C for 48 h; 35°C for 48 h and 45°C for 48 h; and 65% HR). pH, titratable acid, citric, lactic and acetic acids, as well as sugars and ethanol were measured. A cut test was also performed on the cocoa beans fermented 5 and 6 days. As the fermentation time progressed, citric acid concentration decreased until 0.53 g kg−1, whereas both lactic and acetic acids increased until 0.44 and 16.58 g kg−1, respectively. Sucrose content decreased from 12.26 g kg−1 (in fresh) to 6.54 g kg−1 on the 6th day. Fructose and glucose contents increased in the cotyledons from day five, reaching a maximum concentration of 1.14 and 1.01 g kg−1, respectively, on day six. Yeasts were the main microorganisms during the first 24–48 h (8.4 log CFU g−1), while bacterial counts reached its highest number (7.8 log CFU g−1) on day four. Beans fermented 5 and 6 days resulted in more fermented beans (>81%) and less violet ones (<18.4%) than the control.  相似文献   

12.
Sufu is made by solid state fungal fermentation (using Actinomucor elegans) of tofu, followed by salting and maturation in dressing mixtures containing salt, alcohol and various other ingredients. NaCl in dressing mixtures strongly affected the changes in textural properties and the hydrolysis of protein and lipid of sufu. Higher salt contents (14% w/w) resulted in increased hardness (+100%) and elasticity (+18%) and reduced adhesiveness (?30%). Hardness and elasticity could be used to judge the extent of sufu ripening. SDS‐PAGE showed the disappearance of all protein subunits at 80 and 110 g kg?1 salt content; however, some protein subunits were still detectable at 140 g kg?1 salt content after 60 days of ripening. Higher ratios of free amino nitrogen to total nitrogen (FAN/TN = 0.4–0.45) and free amino acids to crude protein (FAA/CP = 0.24–0.26) were observed in sufu with lower (80 g kg?1) salt content. FAN/TN and FAA/CP in white sufu (obtained with dressing mixtures containing only salt and alcohol) were higher than those in red sufu (obtained with dressing mixtures containing angkak or kojic red rice) owing to different dressing mixture compositions. Increases in free fatty acids (FFA) were also observed during ripening. FFA levels in sufu with lower salt content increased rapidly during the first 30–40 days and then increased slowly, probably resulting from the formation of fatty acid esters. Lowering the salt content (80 g kg?1) can shorten the ripening time to 40 days, which is of benefit to manufacturers. However, sufu will spoil, ie undergo souring, during the ripening stage at salt contents of 50 g kg?1 or lower. Copyright © 2003 Society of Chemical Industry  相似文献   

13.
Our objectives were to investigate the proximate composition of two desert truffles (Terfezia claveryi Chatin and Picoa juniperi Vittadini) and to determine the effects of freezing and canning on proximate composition. The moisture content of T claveryi and P juniperi was 730.9 g kg?1 and 637.8 g kg?1 respectively; ash was 42.5 g kg?1 and 82.1 g kg?1 respectively; protein was 159.5 g kg?1 and 225.4 g kg?1 respectively; lipids were 69.5 g kg?1 and 199.4 g kg?1 respectively; fibre was 83.2 g kg?1 and 130.4 g kg?1 respectively; and carbohydrates were 645.5 g kg?1 and 366.6 g kg?1 respectively. The fatty acids composition showed high quantities of linoleic acid 18:2 (45.4% in T claveryi and 53.0% in P juniperi), the rest of the fatty acids in decreasing order were 16:0 > 18 : 1 > 18 : 3 18 : 0 + 22 : 0 > 20 : 0 + 24 : 0 > 14 : 0 + 22 : 1 > 15 : 0 + 16 : 1 + 17 : 0 + 21 : 0 in T claveryi and 18 : 1 > 16 : 0 > 18 : 0 + 18 : 3 + 16 : 1 + 20 : 0 + 22 : 1 > 14 : 0 + 24 : 0 > 15 : 0 + 17 : 0 + 22 : 0 in the P juniperi. Little loss of ash, protein and lipids was observed as a result of industrial processing (p < 0.05). Copyright © 2003 Society of Chemical Industry  相似文献   

14.
In a factorial experiment, the laying performance of White Leghorn hens given diets in which triticale replaced 100, 50 or 0% of barley either in the presence or absence of 210 g kg?1 rice pollard and with two levels (2.5 and 3.5 g kg?1) of methionine was examined. The replacement of barley with triticale had no significant effect on egg production, egg weight or feed conversion efficiency. The inclusion of 210 g kg?1 rice pollard increased the weight (P < 0.01) and reduced the yolk colour (P<0.01) of eggs. Neither triticale nor barley had a significant effect on liver weight and lipid content. Triticale increased the palmitoleic acid content but had no significant effect on the content of other fatty acids in the liver and yolk lipids. Rice pollard increased the concentration of linoleic and arachidonic acids in liver and yolk lipids while the concentrations of myristic, palmitoleic and oleic acids were decreased. Increasing the level of methionine from 2.5 to 3.5 g kg?1 in diets with either triticale or barley or rice pollard had no significant effect on any of the egg production characteristics.  相似文献   

15.
The content of saturated sterols (stanols) was investigated in a small number of samples of hydrogenated fats and oils, and in the ‘free’ and ‘bound’ lipids of various samples of cereals. The sterols, after saponification of the total lipids, were analysed as trimethylsilyl derivatives by GC and identified by GC–MS. Among the hydrogenated fats and oils, coconut oil contained the largest amounts of sitostanol followed by soybean oil (c 80 and 20 g kg−1 of total unsaponifiables, respectively). No sitostanol could be detected in hydrogenated palm oil under the present analytical conditions. Both ‘free’ and ‘bound’ lipids in various samples of wheat, except for wheat germ, contained c 70–120 g kg−1 campestanol and 100–150 g kg−1 sitostanol in total unsaponifiables. In lipids of oats and barley, no campestanol or sitostanol could be detected. Rye total lipids contained 60–90 g kg−1 of campestanol and 100–150 g kg−1 of sitostanol of total unsaponifiables in ‘free’ and ‘bound’ lipids, respectively.  相似文献   

16.
Cyclopropane fatty acids, which can be simply converted to methylated fatty acids, are good unusual fatty acid candidates for long-term resistance to oxidization and low-temperature fluidity useful for oleochemistry and biofuels. Cyclopropane fatty acids are present in low amounts in plants or bacteria. In order to develop a process for large-scale biolipid production, we expressed 10 cyclopropane fatty acid synthases from various organisms in the oleaginous yeast Yarrowia lipolytica, a model yeast for lipid metabolism and naturally capable of producing large amounts of lipids. The Escherichia coli cyclopropane fatty acid synthase expression in Y. lipolytica allows the production of two classes of cyclopropane fatty acids, a C17:0 cyclopropanated form and a C19:0 cyclopropanated form, whereas others produce only the C17:0 form. Expression optimization and fed-batch fermentation set-up enable us to reach a specific productivity of 0.032 g·L−1·hr−1 with a genetically modified strain containing cyclopropane fatty acid up to 45% of the total lipid content corresponding to a titre of 2.3 ± 0.2 g/L and a yield of 56.2 ± 4.4 mg/g.  相似文献   

17.
麦麸是小麦加工的主要副产物,营养丰富且产量大,采用乳酸菌处理麦麸可提高其附加值。为明确乳酸菌发酵对麦麸各组分的影响,作者采用植物乳杆菌、鼠李糖乳杆菌、戊糖片球菌和布氏乳杆菌分别对麦麸进行固态发酵,在48 h内每隔8 h取样,分析可溶性膳食纤维、粗蛋白质、淀粉、总酚、植酸等成分的质量分数及DPPH自由基清除能力的动态变化。结果表明,在麦麸基质中,4株乳酸菌在24 h内生长较为迅速;麦麸经乳酸菌发酵后可溶性膳食纤维质量分数显著提高,其中布氏乳杆菌发酵48 h后可溶性膳食纤维质量分数由4.72%增加至6.58%;随着发酵时间的增加,麦麸中淀粉质量分数逐渐降低,粗蛋白质量分数先增加后降低最后趋于稳定;植物乳杆菌在提高麦麸多酚质量分数方面有更好的效果,多酚质量分数由1.34 mg/g增加至3.86 mg/g,麦麸抗氧化活性显著增加;此外,乳酸菌发酵麦麸可显著降低其植酸质量分数。综合而言,植物乳杆菌和布氏乳杆菌在提高麦麸的营养特性方面具有较好的效果,可有效改善麦麸的综合利用价值。  相似文献   

18.
The contents of low‐molecular‐weight carbohydrates (LMWC; sorbitol, glucose, fructose and sucrose), starch, dietary fibre and organic acids were determined in seven apple cultivars at the start and end of the consumption interval. The cultivars included were Summered, Aroma, Ingrid Marie, Cox Orange, Mutzu, Belle de Boskoop and Jonagold. The total content of LMWC ranged between 615 and 716 g kg−1 dry matter (DM). The dominating sugar was fructose, corresponding to on average 57% (range 48–62%) of the total LMWC. However, in Cox Orange the sucrose content was considerably higher and the fructose and sucrose contents constituted approximately 46% each. Total dietary fibre content was similar in the cultivars (total dietary fibre 160 ± 20 g kg−1 DM), except for Belle de Boskoop which had a higher content (203 g kg−1 DM). Mutzu had a lower proportion of soluble fibre (27% of total dietary fibre) compared with the others (mean 32%). The organic acid content was on average 80 ± 4 g kg−1 DM, except for two of the cultivars (Summered and Belle de Boskoop) which had a higher content (105 ± 6 g kg−1 DM). Interestingly, the organic acid content was only slightly reduced upon storage in the case of Belle de Boskoop, whereas there was a substantial decrease in all the other cultivars (p < 0.001). Sucrose (p < 0.01) and starch (p < 0.05) contents decreased in all cultivars following storage, whereas sorbitol (p < 0.05) and total dietary fibre (p < 0.05) contents increased. It is concluded that the observed differences in composition are of such magnitude that they may affect both nutritional and sensory properties. © 2000 Society of Chemical Industry  相似文献   

19.
The ascorbic acid content and peroxidase activity of raw, canned and frozen (after blanching times of 60, 90, 120 and 150 s) broccoli florets and stems were determined. The ascorbic acid content represented 1.12 and 0.78 g kg−1 fresh weight in raw florets and stems respectively. After blanching (for different times) and freezing, the ascorbic acid content decreased to values of 0.55–0.56 g kg−1 fresh weight in florets and 0.35–0.36 g kg−1 fresh weight in stems. The industrial processing involved in canning decreased the ascorbic acid content to 0.18 g kg−1 fresh weight in florets. The peroxidase activity observed in the florets and stems of raw broccoli was 308.8 and 278.6 µmol min−1 per 100 g fresh weight respectively. The peroxidase activity remaining in frozen florets varied from 0.9 to 0.2%, while that in stems showed values of between 7.5 and 8.4%. These values for stems were within the range recommended for residual activity after blanching and freezing. The peroxidase activity of canned broccoli florets was practically undetectable. © 2000 Society of Chemical Industry  相似文献   

20.
The seeds of 28 species from ‘cerrado’, a typical savanna ecosystem of Brazil, were analysed for total lipid contents and fatty acid distribution. The seeds of 10 species presented contents above 150 g kg−1, the highest yield reaching 335 g kg−1. Distribution of fatty acids based on polyunsaturated compounds seems to be rare in seed oils from ‘cerrado’: only three seed oils were found to be based on linoleic acid and none on linolenic acid. Eight seed oils, four of them Fabales, presented palmitic acid as a dominant constituent. Half of the species presented oleic acid based seed oils. Two species stand out for unusual fatty acid distribution: Qualea grandiflora (Vochysiaceae) with 171 g kg−1 of seed oil presenting 723 g kg−1 of lauric acid and Serjania erecta (Sapindaceae) with 256 g kg−1 of seed oil presenting 623 g kg−1 of eicosenoic acid.  相似文献   

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