首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 31 毫秒
1.
The objective of this investigation was to evaluate physico-chemical and nutritional properties of tempeh flour from a quality protein maize (QPM). In comparison to untreated QPM, the QPM tempeh flour showed a higher (P?0.05) gelatinization temperature (81.7 vs 73.9 °C), and resistant starch (4.24 vs 1.9 g/100 g dry flour), and a lower (P?0.05) gelatinization enthalpy (1.94 vs 2.74 J/g) and total starch content (56.9 vs 62.6 g/100 g dry flour). The essential amino acids (EAAs) content of raw QPM flour was improved by the solid-state fermentation process. The contents of His, Ile, and Leu increased (P?0.05) in 0.81, 0.52, and 1.46 g/100 g protein, respectively. The total sulphur and total aromatic EAAs increased (P?0.05) in 0.55 and 3.45 g/100 g protein, respectively. In untreated QPM flour, the first and second limiting EAAs were Lys and Trp, with EAAs score of 0.72. First and second limiting EAAs in QPM tempeh flour were Trp and Lys, with an EAAs score of 0.84. The SSF process increased (P?0.05) nutritional indicators as follows: protein efficiency ratio (PER) from 1.78 to 2.10, calculated PER from 1.43 to 1.74, and protein digestibility corrected amino acid score from 0.55 to 0.83. It is concluded that based mainly on its nutritive value, fermented flour may be considered for the fortification of widely consumed cereal-based food product (tortillas, bread, cookies, atoles).  相似文献   

2.
Defatted Erythrina variegata flour was prepared from dehusked seed meal by hexane extraction of residual oil. The resulting flour had 403 g kg−1 of protein as compared to 282 g kg−1 in the whole seed-defatted meal. Nitrogen extractability of the defatted flour in water was not much influenced by the length of extraction period above 40 min, but an increased extraction was observed at a higher liquid to solid ratio up to a studied limit of 1:60; the optimal ratio was found to be 1:30. The minimum of 26.9% nitrogen was extracted in the pH range 3.0–4.0 and maximum of 94.8% at pH 12. Addition of sodium chloride (0.1 or 0.5 M) broadened the pH range of minimum nitrogen extractability and shifted it toward a lower pH region. At both concentrations of sodium chloride, a marked increase in nitrogen extractability, in the pH range 3.0–7.0, was observed. Precipitation of protein from an extract of pH 10.0 was maximum (85.3%) at pH 4.75. A higher buffer capacity of the flour was observed in the acidic medium (0.195 mmol HCl g−1 flour) than in alkaline medium (0.093 mmol NaOH g−1). Water absorption and oil absorption values for the whole E. variegata seed flour and the dehusked, defatted flour were 1.81, 1.43 and 1.02, 1.52 kg kg−1, respectively.  相似文献   

3.
Samples of cultivated Ulva clathrata were collected from a medium scale system (MSS, 1.5 × 1.5 m tank), or from a large scale system (LSS, 0.8 ha earthen pond). MSS samples were dried directly while the LSS sample was washed in freshwater and pressed before drying. Crude protein content ranged 20–26%, essential amino acids accounting for 32–36% of crude protein. The main analysed monosaccharides were rhamnose (36–40%), uronic acids (27–29%), xylose (10–13%) and glucose (10–16%). Some notable variations between MSS and LSS samples were observed for total dietary fibre (26% vs 41%), saturated fatty acids (31% vs 51%), PUFAS (33% vs 13%), carotenoids (358 vs 169 mg kg−1 dw) and for Ca (9 vs 19 g kg−1), Fe (0.6 vs 4.2 g kg−1), Cu (44 vs 14 mg kg−1), Zn (93 vs 17 mg kg−1) and As (2 vs 9 mg kg−1). The chemical composition of U. clathrata indicates that it has a good potential for its use in human and animal food.  相似文献   

4.
Trace element levels in honeys from different regions of Turkey   总被引:1,自引:0,他引:1  
A survey of 25 honey samples from different botanical origin, collected all over the Turkey was conducted to assess their trace element contents. The aim of this study was to determine the levels of cadmium (Cd), lead (Pb), iron (Fe), manganese (Mn), copper (Cu), nickel (Ni), chromium (Cr), zinc (Zn), aluminium (Al) and selenium (Se) in honey samples from different regions of Turkey. Trace element contents were determined by a flame and graphite furnace atomic absorption spectrometry technique after dry-ashing, microwave digestion and wet-digestion. The accuracy of the method was corrected by the standard reference material, NIST-SRM 1515 Apple leaves. The contents of trace elements in honey samples were in the range of 0.23–2.41 μg g−1, 0.32–4.56 μg g−1, 1.1–12.7 μg g−1, 1.8–10.2 μg g−1, 8.4–105.8 μg kg−1, 2.6–29.9 μg kg−1, 2.4–37.9 μg kg−1, 0.9–17.9 μg kg−1, 83–325 μg kg−1 and 38–113 μg kg−1 for Cu, Mn, Zn, Fe, Pb, Ni, Cr, Cd, Al and Se, respectively. Iron was the most abundant element while cadmium was the lowest element in the Turkish honeys surveyed. The results showed that trace element concentrations in the honeys from different regions were generally correlated with the degree of trace element contamination of the environment.  相似文献   

5.
An optimised FI-HGAAS method was applied to determine the total selenium concentrations in selected high consumption food (fish, beef, chicken, milk, rice, wheat flour, egg) and to estimate their contribution to the Argentinean dietary intake, whose information is scarce nowadays. Through several optimisation steps a suitable method was achieved showing satisfactory figures of merit for all matrices. Average recovery was 96%, RSD < 5%, LODs ranged 2.0–7.0 μg kg−1 and the accuracy was assessed using DOLT-3 NRC certified reference material. Meat and eggs showed the highest values (in μg kg−1, beef: 42–153; chicken: 62–205; fish: 94–314; canned tuna: 272–282; eggs: 134–217), minor values were found for wheat flour (22–42), rice: (<22), pasta (47–64) and milk (<7–9). An estimated intake of 32 and 24 μg day−1 for adult men and women, respectively, suggested a deficient Se intake, leading to further comprehensive surveys of Se occurrence in Argentina.  相似文献   

6.
《LWT》2004,37(1):59-67
Solid state fermentation (SSF) process represents a technological alternative for a great variety of legumes and cereals, or combination of them, to improve their nutritional quality and to obtain edible products with palatable sensorial characteristics. The objectives of this work were (1) to determine the best combination of SSF process variables (temperature/time) for production of quality protein maize (Zea mays L.) (QPM) tempeh flour, and (2) to characterize physico-chemical properties and nutritionally quality of optimized QPM tempeh flour. Response surface methodology (RSM) was applied as optimization technique, over three response variables: In vitro protein digestibility (PD), true protein (TD) and water absorption index (WAI). A central composite experimental design with two factors [fermentation temperature (FT), fermentation time (Ft)] and five levels (2 factorial, 2 axial, 1 central) was used. The process variables, FT and Ft, had variation levels of 31-36°C and 48-72 h, respectively. Spores from Rhizopus oligosporus were suspended in distilled water (1×106 spores/ml) and used as starter. Predictive models for response variables were developed as a function of process variables. Conventional graphical method was applied to obtain maximum PD, TP and WAI. Contour plots of each of the response variables were utilized, applying superposition surface methodology, to obtain a contour plot for observation and selection of the best combination of FT (35.4°C) and Ft (54.6 h) for production of QPM tempeh, which was dried (52°C, 24 h) and milled to pass through a 80-US mesh (0.180 mm) screen to obtain optimized QPM tempeh flour. This flour had higher (p?0.05) true protein (13.1 vs 9.1 g/100 g, DM), total colour difference (21.7 vs 9.2), WAI (2.9 vs 1.25 g gel/g dry flour), available lysine (5.67 vs 4.2 g lysine/100 g protein) and PD (83.6 vs 78.5%, DM), and lower (p?0.05) lipid content (4.3 vs 6.1 g/100 g, DM), phytic acid (0.8 vs 10.1 mg phytic acid/g, DM), and pH (4.5 vs 6.12) than raw QPM flour.  相似文献   

7.
The selenium content in fruit and vegetable samples from two regions in Portugal were analysed using hydride generation atomic fluorescence spectrometry (HG-AFS) and radiochemical nuclear activation analysis (RNAA) – two analytical methods with very low limits of detection. The lower detection limits of HG-AFS, 3 μg kg−1 and 8 μg kg−1 (according to conditions used for digestion), and for RNAA, 10 μg kg−1, meant that it was possible to determine selenium in samples previously analysed using the replicate sample instrumental nuclear activation analysis (RSINAA) with a higher detection limit associated.  相似文献   

8.
The in vitro digestibility and molecular and crystalline structures of rice starches (Long-grain, Arborio, Calrose, and Glutinous) differing in amylose content were investigated and the relationship between the structure and in vitro digestibility of starch was studied. Long-grain showed the highest amylose content (27.2%), whereas Glutinous showed the lowest amylose content (4.2%). Long-grain had the highest average amylopectin branch chain length (18.8) and proportion (8.7%) of long branch chains (DP ≥ 37), and the lowest proportion (26.9%) of short branch chains (DP 6–12). Among the non-waxy rice starches (Long-grain, Arborio, and Calrose), Calrose had the lowest average chain length (17.7) and the lowest proportion (7.1%) of long branch chains (DP ≥ 37). The relative crystallinity of rice starch followed the order: Glutinous (33.5%) > Calrose (31.4%) > Arborio (31.0%) > Long-grain (29.9%). Long-grain had the highest gelatinization temperature and the lowest gelatinization temperature range, whereas Glutinous showed the highest gelatinization temperature range and gelatinization enthalpy. Arborio had the highest melting enthalpy for amylose–lipid complex among the tested rice starches. Pasting temperature, setback, and final viscosity increased with increasing amylose content, whereas the peak viscosity and breakdown showed negative correlations with amylose content. The rapidly digestible starch (RDS) content of the tested rice starches followed the order: Glutinous (71.4%) > Calrose (52.2%) > Arborio (48.4%) > Long-grain (39.4%). Contrary to this, the slowly digestible starch (SDS) and resistant starch (RS) contents showed an opposite trend compared to RDS. Digestibility (RDS, SDS, and RS) of the rice starches was significantly correlated (p ≤ 0.05) with amylose content, proportions of DP 6–12 and DP 13–24, relative crystallinity, intensity ratio (of 1047 cm−1 to 1022 cm−1 from Fourier transform infrared spectroscopy), swelling factor, amylose leaching, onset temperature of gelatinization, gelatinization temperature range, gelatinization enthalpy, pasting temperature, peak viscosity, breakdown, setback, and final viscosity.  相似文献   

9.
The influence of the drying method on volatile compounds of Rosmarinus officinalis was evaluated. The drying methods tested were convective (CD) and vacuum-microwave (VMD), as well as a combination of convective pre-drying and VM finish-drying (CPD–VMFD). Rosemary drying kinetics was described by a simple exponential model for CD and VMD, while VMFD kinetics consisted of two periods: linear until a critical point and exponential beyond that point. Volatile compounds of rosemary samples were extracted by steam-hydrodistillation and analyzed by GC–MS. Thirty-four compounds were tentatively identified, with α-pinene, bornyl acetate, camphene and 1,8-cineole being the major components. The total volatiles concentration of fresh rosemary (135 g kg−1) decreased considerably during both CD (87.2 g kg−1) and VMD (61.9 g kg−1). CPD–VMFD was the best option for drying rosemary because the time required was relatively short (30 min), and the aroma quality was good according to both instrumental (100 g kg−1) and sensory analyses.  相似文献   

10.
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   

11.
Cell walls were isolated from flesh and skin of five plum varieties corresponding to three species (Prunus domestica L., Prunus salicina Lindl. and Prunus insititia Lindl.) using the alcohol-insoluble solids (AIS) procedure. Yields varied from 83 to 114 g kg−1 dry weight in the flesh and from 192 to 361 g kg−1 dry weight in the skins. Their main sugars were uronic acid (224–322 mg g−1 AIS), cellulosic glucose (139–170 mg g−1 AIS), galactose and arabinose. Galactose and arabinose ratio were variable between the varieties. The degrees of methylation were high (62–84).  相似文献   

12.
Solid state fermentation (SSF) represents a technological alternative for processing a great variety of legumes and/or cereals to improve their nutritional quality and to obtain edible products with palatable sensorial characteristics. The objectives of this work were (1) to determine the best combination of SSF process variables (fermentation temperature FT/fermentation time Ft) for producing chickpea tempeh flour and (2) to characterise the physicochemical and nutritional properties of the product. Response surface methodology was applied as optimisation technique over three response variables: in vitro protein digestibility (PD), true protein (TP) and water absorption index (WAI). A central composite experimental design with two factors and five levels was used. The process variables FT and Ft had variation levels of 31–36 °C and 48–72 h respectively. Rhizopus oligosporus (1 × 109 spores l?1 in distilled water) was used as starter. Prediction models for response variables were developed as a function of process variables. A conventional graphical method was applied to obtain maximum PD, TP and WAI. Contour plots of each of the response variables were superimposed to obtain a contour plot for observation and selection of the best combination of FT (34.9 °C) and Ft (51.3 h) for producing of chickpea tempeh, which was dried (52 °C, 24 h) and milled to pass through an 80‐US mesh (0.180 mm) screen to obtain optimised chickpea tempeh flour. This flour had higher (p ≤ 0.05) TP (25.7 vs 19.7% dry matter (DM)), total colour difference (30.3 vs 16.7), WAI (4.18 vs 2.15 kg gel kg?1 DM), available lysine (42.7 vs 30.4 g kg?1 protein) and PD (83.2 vs 72.2%) and lower lipid content (2.6 vs 6.1% DM), phytic acid (1.1 vs 10.85 g kg?1 DM), tannins (2.65 vs 21.95 g catechin kg?1 DM) and pH (5.9 vs 6.3) than raw chickpea flour. Copyright © 2004 Society of Chemical Industry  相似文献   

13.
In vitro starch digestibility, expected glycemic index (eGI), and thermal and pasting properties of flours from pea, lentil and chickpea grown in Canada under identical environmental conditions were investigated. The protein content and gelatinization transition temperatures of lentil flour were higher than those of pea and chickpea flours. Chickpea flour showed a lower amylose content (10.8–13.5%) but higher free lipid content (6.5–7.1%) and amylose–lipid complex melting enthalpy (0.7–0.8 J/g). Significant differences among cultivars within the same species were observed with respect to swelling power, gelatinization properties, pasting properties and in vitro starch digestibility, especially chickpea flour from desi (Myles) and kabuli type (FLIP 97-101C and 97-Indian2-11). Lentil flour was hydrolyzed more slowly and to a lesser extent than pea and chickpea flours. The amount of slowly digestible starch (SDS) in chickpea flour was the highest among the pulse flours, but the resistant starch (RS) content was the lowest. The eGI of lentil flour was the lowest among the pulse flours.  相似文献   

14.
The concentrations of As, Cd, Cu, Hg and Pb were determined in 54 multi-floral honey samples collected from five regions of Croatia during 2009 and 2010. Element contents decreased in the following order: Cu > Pb > As > Hg > Cd. Significant differences in lead and copper levels were observed between regions. Mean levels of elements (μg kg−1) in all honey samples measured were: 19.7 for As, 1.51 for Cd, 1074 for Cu, 2.72 for Hg and 65.2 for Pb. Copper and lead were the most abundant elements in the Centre region, with range and mean contents of 108–41,271 and 3232 μg kg−1 and 22.0–440 and 131 μg kg−1, respectively. The highest element contents were: As 23.8 μg kg−1 in the South region, Cd 2.11 μg kg−1 in the Southwest region and Hg 2.63 μg kg−1 in the Northeast region. The finding that lead contents in Croatian honey were higher than most reported lead levels in honey from other European countries is of particular concern. These indicate that attention must be focused on setting positions for honey production hives in areas distant from highways and railways.  相似文献   

15.
The objective of this work was to evaluate the technical feasibility of coupling two membrane separation processes, reverse osmosis (RO) and osmotic evaporation (OE), in order to concentrate clarified camu–camu juice, focusing on the vitamin C, phenolic compounds and antioxidant activity of the final product. The juice was firstly pre-concentrated by RO, reaching 285 g kg−1 of soluble solids. During this step, the juice’s osmotic pressure showed to be the main factor controlling mass transfer. The juice was then concentrated by OE, reaching 530 g kg−1 of soluble solids. Vitamin C, total phenolics and antioxidant activity levels of 94.6 g ascorbic acid kg−1, 105.2 g galic acid kg−1 and 762 mmol Trolox kg−1, respectively, were achieved in the final product. The use of integrated membrane processes proved to be an interesting alternative to the concentration of thermosensitive juices, reaching concentration levels up to 7 times for camu–camu juice’s bioactive compounds.  相似文献   

16.
d-Galactose was produced from lactose (200 g l−1) in the batch mode of a simultaneous saccharification and fermentation process (SSF). β-Galactosidases (from Kluyveromyces lactis and Aspergillus oryzae) and yeasts were immobilized in poly(vinylalcohol) hydrogel lens-shaped capsules – LentiKats®. After 20 repeated batch runs with entrapped K. lactis, β-galactosidase and free Saccharomyces cerevisiae (10% v/v inoculum), galactose productivity decreased to 50% and 1.4 kg of galactose were prepared. Compared to this, just 20% decrease of galactose productivity and a 0.9 kg production of galactose were observed for the SSF process with β-galactosidase from A. oryzae after 15 repeated batches under the same conditions. In the process of SSF with co-immobilized enzyme from K.lactis and S.cerevisiae, the galactose productivity increased from 3 g l−1 h−1 to 4.1 g l−1 h−1, which reduced the time of preparation of d-galactose.  相似文献   

17.
For the first time automated on-line solid phase extraction coupled to liquid chromatography tandem mass spectrometry was developed for the simultaneous determination of 13 antibiotics (sulfonamides and tetracyclines) in catfish. The method proposed was validated according to Commission Decision 2002/657/EC, showing good linearity between 2 and 350 μg kg−1, high recovery (80–99%) and reproducibility (13–20%) values, lower detection limits than 0.1 μg kg−1, and quantification limits under 2.4 μg kg−1 (between 39 and 84 times lower than the MRL fixed by the EU). Moreover, the proposed method was also used to determine sulfonamides and tetracyclines in 16 out of 107 samples, all previously analysed by microbiological screening that gave positive results. Five out of 13 antibiotics were found, having tetracycline the higher occurrence (10 samples); in all cases the concentrations were lower than the MRL established.  相似文献   

18.
L. Gašperlin  B. Lukan  B. ?lender  T. Polak 《LWT》2009,42(8):1313-1319
Mutagenic heterocyclic amines (HAs) originate in processed proteinaceous foods. The effects of the presence of skin (with vs. without) and of grilling method (two plate vs. infrared) on the content of HAs in grilled chicken pectoralis superficialis muscle (temperature, 220 °C) were investigated. HA precursors (creatine, creatinine, free amino acids and carbohydrates) and HAs of these raw and grilled breast muscles were determined. The muscles originated from 24 birds of either sex (provenance Ross; aged 40-45 days). The HA content was determined in homogenates of the upper and lower surface slices of the grilled muscles (Ti = 82 °C). A higher content of total free amino acids was seen for the muscle (27.1 mmol kg−1 raw meat) than for the skin (21.7 mmol kg−1 raw meat). The creatine, creatinine and carbohydrate levels in the skin were below the limits of detection. The contents of creatine (31.8-38.7 mmol kg−1) and creatinine (0.24-0.33 mmol kg−1) in the breast muscle were determined. Relatively high levels were seen for glucose (23 mmol kg−1 raw meat) and fructose (10 mmol kg−1 raw meat) in the muscle, with other sugars present at low levels (<2 mmol kg−1 raw meat). For the chicken muscle grilled on a two-plate grill, the contents of total HAs (PhIP, MeIQx, DiMeIQx, Harman and Norharman) were lower with the skin in place than in the muscle grilled without the skin (3.5 μg kg−1vs. 4.8 μg kg−1). Also, during infrared grilling with the skin, lower amounts of HAs were formed than with grilling on the two-plate grill (2.4 μg kg−1vs. 3.5 μg kg−1). On average, the infrared-grilled samples with skin contained 3-fold more total HAs than similar samples without the skin (2.4 μg kg−1vs. 0.8 μg kg−1), with the highest levels seen for PhIP and MeIQx.  相似文献   

19.
The formaldehyde (FA) content in different fish products was evaluated using a solid phase microextraction (SPME)-GC–MS method based on fiber derivatisation with pentafluorobenzyl-hydroxyl-amine hydrochloride. LOD and LOQ values of 17 and 28 μg kg−1, respectively were calculated. Fish quality was assessed by the analysis of 12 species (sea-fish, freshwater-fish and crustaceans), revealing variable FA levels. Fresh, deep frozen, canned, boiled and roasted fish were analysed; cooking always produced a decrease in the analyte content. Fish belonging to the Gadidae family were the samples with the highest FA concentration (from 6.4 ± 1.2 mg kg−1 to 293 ± 26 mg kg−1), in four cases out of 14 exceeding the value of 60 mg kg−1 proposed by the Italian Ministry of Health. Storage on ice was also investigated, showing moderate FA production also at temperature around 0 °C. FA contents lower than 22 mg kg−1 were finally found in all the other samples.  相似文献   

20.
A simple and fast method for the simultaneous analysis of thiobencarb, deltamethrin and 19 organochlorine pesticide residues in fish by gas chromatography–mass spectrometry was investigated in this study. Samples are extracted with acetonitrile. Most of lipids in the extract are eliminated by low-temperature cleanup, prior to solid-phase extraction cleanup. The lipids extracted from the fish samples were easily removed without any significant losses of the pesticides. Aminopropyl (NH2) cartridge was effective to eliminate the remaining interference. Spiked experiments were carried out to determine the recovery, precision and limits of detection (LODs) of the method. The method detection limits ranged from 0.5 μg kg−1 to 20 μg kg−1, whilst recoveries of the pesticides were in the range of 81.3–113.7% with relative standard deviations ?13.5% at a spiked concentration of 0.05 mg kg−1, 0.02 mg kg−1 and 0.1 mg kg−1. The newly developed method is demonstrated to give efficient recoveries and LODs for detecting pesticide multiresidues in fish.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号