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1.
The extraction of yellow gentian root (Gentiana lutea L .)   总被引:1,自引:0,他引:1  
 Several solvents have been investigated for the preparation of bitter compounds of gentian roots (Gentiana lutea L.) for food applications. The highest concentrations of the bitter compounds, amarogentin and gentiopicroside, were obtained with ethanol : water 55 : 45 (v/v), propylene glycol: water 30 : 70 (v/v) and ethanol: propylene glycol: water 20 : 20 : 60 (v/v/v). Enzyme treatment prior to solvent extraction gave a greater extract yield (3.5%) but the amarogentin and gentiopicroside concentrations remained the same. The volatile fraction was affected by the solvent used through the formation of esters of organic acids from the plant. Received: 22 January 1997 / Revised version: 18 March 1997  相似文献   

2.
Cassava roots contain cyanogenic glucosides. Malawian farmers classify cultivars into two groups based on the perceived danger of eating raw roots that they associate with bitterness. In the vernacular, cultivars that produce roots with bitter taste are called vyakubaba (bitter), whereas those yielding non‐bitter roots are called vyakuzizra (cool). In the scientific literature they are distinguished as ‘bitter’ or ‘sweet’. Roots from ‘bitter’ cultivars are processed prior to consumption. We studied the ability of farmers to predict the cyanogenic glucoside levels of 492 roots from the 10 most commonly grown cultivars. Twenty‐eight farmers predicted the taste of each of the cultivars that they grew, and scored bitterness on a five‐point scale by tasting the root tip. Thereafter cyanogenic glucosides were determined on half of the root, while a taste panel scored the taste of the other half. The mean cyanogenic glucoside level in 132 roots from ‘cool’ cultivars was 29 mg HCN eq kg?1 fresh weight (CI 25–33, range 1–123) and in 360 roots from ‘bitter’ cultivars was 153 mg HCN eq kg?1 fresh weight (CI 143–163, range 22–661). Farmers' distinction of ‘cool’ and ‘bitter’ cultivars predicts glucoside levels. The tasting of the tip of the root improved the farmers' prediction of toxicity. Scoring of bitterness by a trained taste panel showed a stronger correlation with glucoside levels (r2 = 0.67). This suggests that cyanogenic glucosides confer the bitter taste, notwithstanding the probability of additional modifying intrinsic factors. Copyright © 2004 Society of Chemical Industry  相似文献   

3.
Thua nao, a traditional, proteolytic, fermented soybean condiment of northern Thailand, was prepared from cooked whole soybeans by natural flora fermentation. The microbial flora during the fermentation was dominated by Bacillus species. The formation of volatile compounds during the fermentation was studied. In addition, the volatile compounds of two samples of commercial dried thua nao and two samples of commercial Japanese natto were analysed. Fermentation led to a large increase in the concentration of total volatile compounds, from 35 µg kg?1 wet weight in cooked soybeans to 3500 µg kg?1 wet weight in 72 h fermented material. The major volatile compounds in fermented beans were 3‐hydroxybutanone (acetoin), 2‐methlybutanoic acid, pyrazines, dimethyl disulphide and 2‐pentylfuran. Sun drying of 72 h fermented material resulted in the loss of 65% of total volatiles, including important aroma compounds. The commercial dried thua nao samples had low concentrations of total volatile compounds (380 µg kg?1 wet weight). It is suggested that improved drying/preservation methods are needed to retain aroma compounds in the traditional products. The natto samples were devoid of aldehydes, aliphatic acids and esters, and sulphur compounds, whereas the thua nao samples contained a diversity of these compounds. Previous investigators have reported these compounds in natto and it is not possible to suggest the existence of systematic differences between the volatile compounds in traditional thua nao prepared with an undefined, mixed microbial flora and those in natto fermented with Bacillus subtilis. © 2001 Society of Chemical Industry  相似文献   

4.
BACKGROUND: Oxidation of fatty acids (FA) during field wilting of herbage could cause extensive losses of polyunsaturated FA. Recent studies showed a variable effect of wilting on the losses of FA. This suggests that environment and management conditions influence the loss of FA during wilting. The present study investigated the stability of FA in untreated and mechanically bruised perennial ryegrass, wilted under field conditions for 0, 12, 24, 36 and 48 h, or wilted under controlled climate conditions at three temperatures (15, 25 or 35 °C) and two light (dark or light) regimes to dry matter (DM) contents of 425, 525 or 625 g kg?1. RESULTS: During 48 h of field wilting, the total FA content declined (15.2 to 11.9 g kg?1 DM) consistently, despite an increase in herbage DM content (197 to 676 g kg?1). Under controlled climate conditions, the herbage total FA content declined (15.1 to 11.7 g kg?1 DM) mainly during the prolonged (56 to 62 h) initial drying to a DM content of 425 g kg?1 and did not decline with further drying to DM contents of 525 and 625 g kg?1. The decline in total FA was associated with a parallel decline in C18:3 content under field (9.15 to 6.36 g kg?1 DM) and controlled (9.12 to 6.15 g kg?1 DM) conditions. Concomitantly, the proportion of C18:3 in total FA decreased, whilst the proportion of C16:0 and C18:0 increased. Lower losses of FA (P < 0.05) were observed at 15 °C compared to 25 and 35 °C. Light did not affect the losses of FA during wilting. CONCLUSIONS: The duration of the wilting period mainly affected the changes in FA content and composition. Stability of FA in herbage could be increased by minimising the duration of wilting. Copyright © 2011 Society of Chemical Industry  相似文献   

5.
A problem concerning significant amounts of nicotine in dried wild mushrooms (mainly Boletus edulis from China) has been reported to the European Commission. As a consequence, the European Food Safety Authority (EFSA) proposed temporary maximum residue levels (MRLs) of 0.036 mg kg?1 for fresh wild mushrooms and 1.17 mg kg?1 for dried wild mushrooms (2.3 mg kg?1 for dried ceps only). The EFSA also highlighted the necessity for a monitoring and testing programme to be launched by food business operators at the start of the 2009 harvest season. In the present study, a quick and sensitive analytical method for routine analysis of nicotine in fresh and dried mushrooms was developed and validated by a single-laboratory procedure. The method, which employs an LC–MS/MS system and (±)-nicotine-d 4 as internal standard, has a limit of quantification of 6 and 60 µg kg?1 for fresh and dried product, respectively. Analyses of samples spiked with different levels of nicotine showed recoveries ranging from 107 to 122%, with relative standard deviations of 2.9–10.1% depending on the spiking level. The combined uncertainties, calculated at a low level for frozen (0.015 mg kg?1) and a high level for the dried (2 mg kg?1) matrix, were 13 and 10%, respectively. Application of the method to real samples of mushrooms purchased on the market or obtained from local producers showed nicotine levels ranging 0.01–0.04 and 0.1–4.5 mg kg?1 in fresh/frozen and dried matrices, respectively. To establish reasons for the unexpectedly high levels of the nicotine in dried matrices, preliminary laboratory experiments involving drying mushrooms were performed under various conditions.  相似文献   

6.
The composition of the leaves of cocoyam (Xanthosoma sagittifolium) and of two trees (Trichanthera gigantea and mulberry, Morus alba), their nutritive value in pigs and voluntary intake by pigs were determined. The average protein content ranged from 170 to 240 g kg?1 dry matter (DM) and that of neutral detergent fibres from 218 to 398 g kg?1 DM. The leaves are interesting sources of calcium (up to 69 g kg?1 DM), potassium, iron and manganese. The proteins are well balanced in essential amino acids, with lysine ranging from 43 to 57 g kg?1 proteins. The apparent faecal digestibility was determined by difference in 35 kg pigs fed a diet containing 35% leaf meal. The digestibility coefficients of DM, N and energy were, respectively, 47–57, 33–36 and 51–53%. The digestible energy value ranged from 1.674 to 2.037 kcal kg?1 DM. The voluntary intake of Trichanthera and Xanthosoma was measured in sows weighing 100 kg on average. The intake reached 3.4 kg fresh leaves day?1 (0.51 kg DM) and 1.0–1.1 kg dry leaf meal/day. It is concluded that low energy density is the main limiting factor of tree foliage for pig nutrition but that they are good sources of minerals and well‐balanced proteins. Copyright © 2005 Society of Chemical Industry  相似文献   

7.
Perennial ryegrass was ensiled in laboratory silos after addition of formic acid (850 g kg?1) or sulphuric acid (906 g kg?1) at rates of 0, 2, 4 and 6 litres t?1 fresh grass. Silos were opened after 6, 18 and 90 days and the silage subjected to chemical and microbiological analysis. The untreated control was poorly fermented with a final pH of 4.7, a butyric acid concentration of 19 g kg?1 dry matter (DM) and an NH3-N content of 275 g kg?1 total nitrogen (TN). For the formic acid treatments the 2 litre t?1 and 6 litre t?1 levels both produced well-preserved silages but they were of different types. The silage treated with 2 litre t?1 had a pH of 4.0, a lactic acid concentration of 92 g kg?1 DM and 161 g NH3-N kg?1 TN, whereas with the 6 litre t?1 treatment, fermentation had been severely restricted. The pH was 4.2, the lactic acid concentration was only 8 g kg?1 DM and the NH3-N content was 80 g kg?1 TN. However, formic acid at 4 litre t?1 produced a badly fermented silage of final pH 5.0 with lactic acid and butyric acid concentrations of 16 and 15 g kg?1 DM, respectively, and an NH3-N content of 149 g kg?1 TN. Sulphuric acid at 2 and 4 litres t?1 produced silages of low lactic acid contents, 36 and 24 g kg?1 DM, and they also contained butyric acid in concentrations of 13 and 11 g kg?1 DM; respective NH3-N contents were 206 and 114 g kg?1 DM. When sulphuric acid was added at 6 litres t?1, despite a reduction in the pH of the grass to 3.5, fermentation was not restricted as it was with the equivalent level of formic acid. Lactic acid was present at 27 g kg?1 DM and the ethanol concentration was very high at 66 g kg?1 DM; the sulphuric acid-treated silages were characterised by high yeast counts. At the higher rates of addition, formic acid reduced the.  相似文献   

8.
The sugar content was determined of 19 cultivars of swede (Brassica napus ssp rapifera L) grown in rows 50 and 75 cm apart. Sugar concentration ranged from 54.3 to 78.7 g kg?1 fresh weight and was positively correlated with dry matter content which ranged from 90.4 to 138.7 g kg?1 fresh weight. The average concentration of fructose, glucose and sucrose in the dry matter was 225.0, 328.4 and 34.5 g kg?1 DM, respectively. The high-dry-matter cultivars tended to have less fructose and more sucrose than the low-dry-matter ones, but total sugar concentration in the dry matter was not associated with dry-matter content. Row width had little effect on sugar content compared with the differences between cultivars. The implications for the feeding value of swedes are discussed.  相似文献   

9.
BACKGROUND: The root powder of Periploca laevigata is used for preparing soft drinks and as an aromatic in Tunisia. The infusion or decoction of its root bark has widespread use in folk medicine. The plant is used to treat digestive disorders and hypertensive effects as well as other health problems. RESULTS: The antioxidant activities of extracts of P. laevigata root bark obtained with solvents of different polarity were investigated using assays of 1,1‐diphenyl‐2‐picrylhydrazyl radical‐scavenging activity, ferric‐reducing capacity, β‐carotene‐bleaching ability, hydroxyl radical‐scavenging activity and lipid peroxidation inhibition. The methanol extract, with the highest amount of total phenolics and flavonoids, showed the highest antioxidant activities in all assays, followed by the water extract. Gas chromatography/mass spectrometry was used to determine the composition of the water and methanol extracts. Thirty‐four compounds were identified in the methanol extract, with proflavine (516.2 g kg?1 dry matter (DM)) and 4‐methoxysalicylaldehyde (198.3 g kg?1 DM) being the most abundant. Sixteen compounds were identified in the water extract, of which 4‐hydroxy‐3‐methoxyphenethylene glycol (351.2 g kg?1 DM) was the main component. CONCLUSION: As far as is known, this is the first report on the chemical composition and biological activities of phenolic extracts from P. laevigata. The results of the study indicate that the root bark of this plant might be a good candidate for further investigation in developing new antioxidants. Copyright © 2009 Society of Chemical Industry  相似文献   

10.
The nutrient and antinutritional factor content of 18 pea lines was studied. The following levels were found: non‐protein nitrogen 5.2–10.2 g kg?1 DM, protein nitrogen 35.3–42.4 g kg?1 DM, lysine 50.7–76.3 g kg?1 protein DM, histidine 17.8–24.8 g kg?1 protein DM, tyrosine 22.6–30.0 g kg?1 protein DM, protein 25.9–31.9% DM, in vitro protein digestibility 89.3–95.6%, vitamin B1 5.9–10.3 mg kg?1 DM, vitamin B2 1.1–3.7 mg kg?1 DM, sucrose 11.6–25.4 g kg?1 DM, raffinose 4.1–10.3 g kg?1 DM, stachyose 10.7–26.7 g kg?1 DM, verbascose 0.0–26.7 g kg?1 DM, total α‐galactosides 22.6–63.4 g kg?1 DM, trypsin inhibitor activity 0.8–8.4 TIU mg?1 DM, inositol hexaphosphate 2.3–6.5 g kg?1 DM, inositol pentaphosphate 0.1–1.8 g kg?1 DM and total inositol phosphates 2.8–7.1 g kg?1 DM. Peas with yellow cotyledons had the highest trypsin inhibitor activities, those with light green cotyledons had the highest lysine contents, and those with dark green cotyledons were the richest in vitamins B1 and B2. Peas with brown testae had the lowest verbascose and sucrose contents, while they were the richest in inositol hexaphosphate. Smaller peas were characterised by the highest protein nitrogen contents as well as the highest contents of vitamins B1 and B2, verbascose and inositol pentaphosphate. Peas of medium size showed the lowest verbascose, α‐galactoside and vitamin B2 contents. Bigger peas showed the lowest inositol pentaphosphate contents. © 2003 Society of Chemical Industry  相似文献   

11.
A random sample of fresh cassava roots and cassava products, purchased at various retail outlets in Singapore during 2016–2017, had total cyanogenic potential (CNp–expressed as mean ± standard deviation, mg kg−1 HCN, fresh weight basis) as follows: fresh roots (n = 66) from three SE Asian countries, 59.0 ± 19.2; peeled chilled root pieces from Malaysia (20 × 1-kg packs), 38.5 ± 16.5; cassava flour from Indonesia (8 × 1-kg packs), 11.7 ± 8.2; dried Indonesian chips for home frying (5 × 250 g packs), 61.6 ± 16.5; one pack (120 g) of Malaysian ready-to-eat (RTE) chips, 17.1 ± 3.2. CNp in all flour and RTE chips was below 20 mg kg−1. The majority of fresh roots (59.1%) and packs of dried chips (80%), and 15% of packs of peeled chilled root parenchyma, exceeded the Codex Alimentarius limit (50 mg kg−1) for ‘sweet’ (boil-and-eat) cassava.  相似文献   

12.
The chemical composition of the seed shell of the apricot (Prunus armeniaca) were investigated. Acid and neutral detergent fibres (ADF and NDF) and their fractions—hemicellulose, cellulose and lignin—were determined. The NDF content was about 920 g kg?1 DM. The concentrations of oils, soluble sugars, pectins, polyphenolic compounds, proteins and mineral elements were also determined. None of these fractions was present at levels higher than 25 g kg?1 DM. Essential amino acids comprised 38-41% of the total amino acids. Potassium (2.44 g kg?1) was the most abundant element, followed by calcium (1.15 g kg?1). Some possible applications for apricot seed shell are considered.  相似文献   

13.
Leaf meals (LMs) from freshly harvested leaves of butterfly pea (Centrosema pubescens), devil bean (Mucuna pruriens), flamboyant flower (Delonix regia), Bauhinia tomentosa, coast wattle (Acacia auriculiformis), quick stick (Glyricidia sepium) and ipil‐ipil (Leucaena leucocephala) were analysed for their nutrient and anti‐nutritional content. Then, leaf protein concentrates (LPCs) were produced from the leaves by fractionation and characterised along with the fibrous residues. On average, the LM contained 181 g kg?1 dry matter (DM) CP (range: 100–280 g kg?1 DM), 139 g kg?1 DM crude fibre (range: 77–230 g kg?1 DM) and 133 g kg?1 DM ether extract (range: 86–165 g kg?1 DM) while the gross energy averaged 17.0 MJ kg?1. On average, leaf protein fractionation enhanced the CP, ether extract and the gross energy in the LPC by 39.5%, 33.5% and 22.0%, respectively, while the crude fibre of the LMs was reduced by 41%, on average, in the LPCs. Fractionation reduced the mineral content of the leaves generally. The mean phytin content varied from 0.36 g kg?1 in LPCs to 0.86 g kg?1 in leaf meal, while the mean phytin‐P content varied from 0.10 g kg?1 in LPCs to 0.24 g kg?1 in leaf meal. The total phenol levels in the LMs were reduced by 33.7% in the LPCs, on average. These results suggest that, while the LPCs from these plants could be used as protein supplements in non‐ruminant feeds in regions where there is an acute shortage of plant protein, the LMs or LPC fibrous residues could be fed to ruminant animals. Copyright © 2006 Society of Chemical Industry  相似文献   

14.
Perennial ryegrass (Lolium perenne L) was ensiled in laboratory silos after addition of glucose or xylose at rates of 0, 25, 35 and 45 g kg?1 fresh grass. In addition, an inoculum of Lactobacillus plantarum, supplying 106 organisms g?1 fresh grass, was applied to all treatments. Silos were opened after 7, 21 and 100 days and the silage was subjected to chemical and microbiological analysis. AH silages were well fermented with pHs between 3·60 and 3·70 and low NH3-N concentrations (<95 g kg?1 total nitrogen) and an absence of butyric acid. Glucose was virtually completely consumed within 21 days but 0·30–0·50 of the xylose doses remained after 100 days. Lactic acid concentrations were not increased by the addition of sugars, but the glucose treatments were associated with very high concentrations of ethanol, 60–100 g kg?1 DM, and the xylose additions produced very high concentrations of acetic acid, 60–135 g kg?1 DM. Most(>0·80) of the glucose that disappeared could be accounted for in ethanol formation but the xylose consumed could be accounted for only if the lactic acid produced in its fermentation was metabolised further to acetic acid; indeed, for the two higher doses of xylose, the concentrations of lactic acid were reduced from the control value of 177 g kg?1 DM to 140 and 120 g kg?1 DM, respectively. The results indicate that the provision of extra sugar, as hexose or pentose, allows yeasts to assume a more prominent role in the fermentation with consequent wasteful fermentation of sugars. Furthermore, the suggestion is that xylose may indirectly, via a stimulation of lactate-assimilating yeasts, encourage further metabolism of lactic acid to acetic acid.  相似文献   

15.
Lucerne (Medicago sativa L) silages made in test tube silos at various dry matter (DM) levels (290-537 g kg?1) with and without addition of glucose (20 g kg?1 herbage) at ensiling were stable during 7 days of aerobic exposure. Lucerne silages taken from seven farm silos were similarly stable while three others were unstable (average DM loss of 62 g kg?1 DM and pH increase from 4.35 to 7.58 in 7 days). Under similar circumstances, maize (Zea mais L) silage had a high DM loss (164 g kg?1 DM) and an increase in pH from 3.94 to 8.13. Silages were inoculated with yeast (1 × 106 CFU g?1 silage) isolated from aerobically deteriorating farm-scale lucerne and maize silages. The stable lucerne silages were not destabilised by inoculation, but the instability of unstable lucerne silages was increased. Aerobically unstable maize silage and stable lucerne silage were inoculated and studied separately or as a 50:50 mixture. There was a distinct lag in the development of aerobic instability in the mixture compared with maize silage alone. In another experiment, the growth of the inoculum in malt agar (pH 3.5) as affected by the presence of fresh and ensiled lucerne (six cultivars), birdsfoot trefoil (Lotus corniculatus L) and red clover (Trifolium pratense L) was studied. The legume herbages did not inhibit yeast growth whereas the corresponding silages did. Five aerobically stable lucerne silages inhibited yeast development in the media whereas unstable maize silage did not. It is concluded that aerobic stability was not related to silage DM, pH, yeast numbers or glucose addition at ensiling. Stability appeared to be due to the presence of an inhibitor (or inhibitors) produced during ensilage.  相似文献   

16.
The influence of dietary levels of L ‐threonine (Thr) on growth and immune response was investigated in growing (0–5 weeks of age) Japanese quails (n = 288). Three dietary treatments were formulated using three levels of Thr [9.6, 10.2 and 11.2 kg?1 diet dry matter (DM)] at a fixed protein level of 233 g kg?1 and an energy level of 12.15 MJ (2900 kcal) metabolizable energy (ME) kg?1 feed dry matter. A metabolism trial with a 3‐day collection period was conducted at the third week of age employing all the birds. The cell‐mediated (using PHA‐P) and humoral (SRBC response) immune responses were measured at the fourth week of age. Carcass traits were assessed at the end of fifth week of age. Body weight gain was lower (P < 0.01) in birds received 9.6 g Thr kg?1 DM than in groups fed 10.2 g or 11.2 g kg?1 DM in the diet, but there was no significant difference in gain between the groups fed 10.2 or 11.2 g Thr kg?1 DM in the diet. Feed intake differed significantly owing to Thr levels being lowest (P < 0.05) at 9.6 g Thr kg?1 DM in the diet. Feed conversion ratio (FCR), protein efficiency and energy efficiency improved at the 11.2 g kg?1 level from 0 to 3 weeks of age; however, from 3 to 5 weeks of age, better FCR emanated from a diet with 9.6 g Thr kg?1 DM. The nitrogen balance did not differ (P > 0.05) with Thr level. Carcass traits, relative weight of immune organs and cell‐mediated (PHA‐P) and humoral (SRBC response) immune responses did not differ significantly (P > 0.05) as a result of the dietary treatments. Copyright © 2006 Society of Chemical Industry  相似文献   

17.
Stevia rebaudiana Bertoni plants grown in vitro and ex vitro were investigated for variations in the profile of steviosides in their leaves, shoots, roots and flowers. Steviosides were extracted by hydrolysis and esterification, evaporated to dryness and dissolved in methanol for quantitative analysis by high‐performance liquid chromatography (HPLC). The HPLC analysis and separation profiles indicated the presence of several different steviosides, predominantly eight known sweet diterpene glycosides. The most abundant compounds identified were steviolbioside, stevioside, rebaudiosides C and A and dulcoside A. The highest stevioside contents were recorded in 1‐month‐old greenhouse leaves (64.80 g steviolbioside kg?1 dried plant material) and in vitro leaves (0.99 g rebaudioside A kg?1 dried plant material). The recovery of steviosides from the leaves by methanol extraction was 90%. This is the first time that the eight predominant sweet diterpene glycosides in the various plant parts of S. rebaudiana have been investigated. Copyright © 2006 Society of Chemical Industry  相似文献   

18.
Research reports on the ethnomedical and pharmacological potential of Kigelia africana extracts. In this study, the nutritional potential of K. africana seed and seed oil was evaluated by chemical analyses. Organic matter and ash constituted 915.23 ± 7.98 g kg?1 DM and 49.05 ± 4.55 g kg?1 DM of the seed mass, respectively. Oil constituted 492.2 g kg?1 DM of the seed mass with oleic acid, linoleic acid and α‐linolenic acid constituting 17.6%, 12.9% and 54.3%, respectively, of the seed oil. Vitamin E concentration was 0.94 ± 0.25 μg g?1. Crude protein was 357.35 ± 3.39 g kg?1 DM. Arginine (6.14 ± 0.31 g per 100 g) as the most abundant amino acid and hydroxyproline (0.11 ± 0.06 g per 100 g) the least. Phosphorus (1123.2 mg per 100 g) and calcium (56.1 mg per 100 g) were, respectively, the most and least abundant minerals. Gross energy was 29.6 ± 0.06 MJ kg?1. Kigelia africana seeds could be exploited as nutrient‐dense dietary supplement rich in protein, oleic acid and essential fatty acids.  相似文献   

19.
The peach palm (Bactris gasipaes Kunth) is the starchy fruit of a palm tree widely cultivated in Central and South America. The present study aimed at determining its chemical composition and its nutritive value in rats. The average chemical composition of 17 samples was as follows: 410 g kg?1 water and, in g kg?1 of dry matter (DM), 54 g crude protein, 114 g oil, 39 g neutral detergent fibre, 716 g starch, 21 g sugars and 18 g ash. The main variability was observed for the oil (60–180 g kg?1 DM) and starch (590–780 g DM) contents. The proteins contained, on average, in g kg?1 of proteins, 49 g lysine, 13 g methionine, 19 g cysteine, 39 g threonine and 7 g tryptophan. The mineral fraction contained, per kg DM: 1.0 g Ca, 0.8 g P, 0.6 g Mg, 0.3 g Na, 44 mg Fe, 4 mg Cu and 10 mg Zn. The digestibility of four peach palm genotypes was determined in rats fed a diet composed of 350 g kg?1 of peach palm and 650 g of a control diet based on maize and soybean meal. The digestibility of DM, energy, starch and protein of peach palm alone reached, on average 91, 87, 96 and 95%, respectively. No difference was observed between varieties, except for starch (p < 0.05). On average, peach palm contained 51 g of truly digestible protein kg?1 DM and 3.691 kcal digestible energy kg?1 DM. A growth trial was also carried out for 1 month on rats (initial weight: 78 g) fed a diet containing 0, 200, 400, 600 or 800 g peach palm kg?1, at the expense of a diet composed of maize starch and casein. The growth rate of the rats decreased (p < 0.05) as the peach palm concentration increased. The growth decrease was due to a decrease (p < 0.05) in DM intake and to the lower quality of the peach palm protein. It is concluded that peach palm is mainly an energy source for humans and animals. It is poor in protein and minerals but can be consumed in large amounts. Copyright © 2005 Society of Chemical Industry  相似文献   

20.
The influence of the drying method on volatile compounds of Origanum vulgare was evaluated. The drying methods tested were convective (CD) at 60 °C and vacuum-microwave (VMD), as well as a combination of convective pre-drying and VM finish-drying (CPD–VMFD). The volatile compounds of fresh and dried oregano were extracted by steam-hydrodistillation and analyzed by GC–MS. Oregano drying kinetics was described by a simple exponential model for CD and CPD–VMFD, while VMD kinetics consisted of two periods: linear until a critical point and exponential beyond that point. Thirty-four compounds were tentatively identified, with carvacrol, thymol, and γ-terpinene, being the major components. The total volatiles concentration of fresh oregano (33.0 g kg−1) decreased significantly during drying, independently of the method used (CD: 10.2 g kg−1, CPD–VMFD: 13.1 g kg−1, and VMD: 27.9 g kg−1). The final conclusion was that VM dehydrated Polish oregano was of better aromatic quality than that dried using hot air.  相似文献   

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