Carrots determination

Hedren, F., Diaz, V., and Svanberg, U., Estimation of carotenoid accessibility from carrots determined by an in vitro digestion method, Eur. J. Clin. Nutr, 56, 425, 2002. 

The extrapolated values together with results of the second calibration method are shown in Table V. With the exception of cabbage, agreement to better than 0.2% was found in the results of the two methods for the various foods. The proper refluxing time, for a rapid determination, was then selected from the data for the high temperature extraction shown in the last four columns in Table V. The required times varied from 5 minutes for onions and carrots to 30 minutes for celery. The shortness of these times as compared with other methods illustrates the potential usefulness of the Fischer method as a rapid control method, even though its accuracy is uncertain. 

Ash and minerals (Ca, Na, K and Mg++) content was determined in AIS of fresh as well as canned carrots (Table 3). The native Ca " bound in the ceU wall components of fresh carrots was found to be 10.9 mg/g AIS. In the presence of CaClz the conventionally canned carrots showed a sharp increase in Ca ... 

The third described enzyme form with pH optimum about 4.7 [11, 4], we found in Fraction C - the fraction from carrot roots pulp (Fig. 2). We supposed that this form of exopolygalacturonase is relatively strongly bound on carrot cell walls and so it can be released only by higher salt concentrations. The approximative molecular mass determination on Superose 12 (Fig. 3c) showed the molecular mass about 50 000 for this form and the second, with more acidic pH optimum, form present in the fraction. The further characterization of these enzymes showed the exopolygalacturonase with pH optimum 4.7 to be identical with enzyme described sooner by Pressey and Avants [4] and exopolygalacturonase with pH optimum 3.8 to be identical with the enzyme from Fraction A. In conclusion, the exopolygalacturonase form with pH optimum 3.8 can be considered to be the main enzyme form present in carrot roots. 

In addition to HPLC/fluorescence, there are references to the use of both APCI and/or ESI with HPLC/MS for the determination of A/-methyl carbamate insecticides in a variety of matrices." Ongoing studies at the US EPA for the determination of /V-methyl carbamate insecticides in nine fmits and vegetables at the 1.0 ngg level are described below. The fruits and vegetables investigated were cranberries, peaches, blueberries, kiwi, carrots, tomatoes, potatoes, lettuce, and grapefmit juice. The purpose of including an account of this work is to illustrate why HPLC/MS/MS is the method of choice for residue work at the 1.0 ng g level, especially for difficult matrices. 

Kohman (3) determined that spinach interfered with growth and bone formation. Studies were conducted on 21-day-old rats for 21 or 28 days and body calcium determined. The diets furnished about 0.22% calcium supplied by calcium carbonate, calcium oxalate, 8.2% spinach, or 4.5% turnip greens. The supplements were added to a diet containing meat, peas, carrots, and sweet potatoes. 

Mean 3-day calcium balances, determined for from 2-5 periods, were positive for all diets, but were lower on the diets containing carrots and spinach. The authors concluded that children do not utilize calcium from vegetables as well as that from milk. 

Belanger A, Hamilton HA. 1979. Determination of disulfoton and permethrin residues in an organic soil and their translocation into lettuce, onion and carrot. J Environ Sci Health [B] 14 213- 226. 

Because concentrations of thorium in foods are very low, very few data exist. The thorium-232 content in fresh fruits, vegetables, and tea was determined (in pCi/g), and the values are listed in Table 5-1. Vegetables grown in an area of high natural activity in Brazil had the following concentrations of thorium (pg/g in dry sample) (Linsalata et al. 1987) brown beans, 0.011 potato, 0.0019 zucchini, 0.011 corn, 0.0022 carrot, 0.0074 and sweet potato, 0.0027. These authors did not observe rapid transport of thorium-232 from soil to the edible parts of the plants. 

Beitler MK, Chin HB. 1995. Improved determination of chlorite and chlorate in rinse water from carrots and green beans by liquid chromatography and amperometric and conductivity detection. J AO AC Int 78(3) 878-883. 

DC046 Kolattukudy, P. E., K. Kronman, and A. ]. Poulose. Determination of structure and composition of suberin from the roots of carrot, parsnip, rutabaga, turnip, red beet and sweet potato by combined gas-liquid chromatography and mass spectrometry. Plant Physiol 1975 55 567. 

Minshall and Helson (7) of the Dominion Department of Agriculture at Ottawa, Canada, have studied the physiological action of petroleum naphtha on carrots, parsnips, and several weeds including mustard. They used infrared absorption apparatus, and by means of readings taken at 10-second intervals following oil application, determined that photosynthesis ceased abruptly for all plants studied. With parsnips, photosynthesis was resumed within 30 minutes after application it was one third of norm at the end of 3 hours, and at the end of 48 hours reached approximately the original rate before treatment. Parsnips did not wilt following treatment. The common mustard plant had a... 

Polybrominated Diphenyl Ethers. Information about the concentrations of PBDEs in food stuffs is very limited. Recently, Ohta et al. (2002) determined the concentration of total PBDEs in vegetables and meat samples from Japan. The concentrations of PBDEs in spinach, potato, and carrot were 134, 47.6, and... 

The biochemical basis of CAM-induced stimulation of Ca2+-ATPase activity in carrot cells was studied further by determining the parameters of the Ca2+-translocating reaction of the enzyme in the presence and absence of exogenous CAM, using EGTA-treated plasma membrane [45], The affinity of Ca2+-ATPase for Ca2+ was considerably increased by... 

Rustan et al. (123) used an isocratic HPLC method for the determination of alpha-, gamma-, and delta-tocopherol, BHT, BHA, PG, OG, DG, NDGA, TBHQ, ascorbyl palmitate, and beta-carotene in foods. An RP18 column was used in experiments, and seven mobile phases based on various combinations of acetonitrile, methanol, water, and tetrahydrofuran were tested. Trials with carrot juice, dried milk formula for infants, and aperitif cakes showed that all 12 antioxidants could be determined by a single isocratic HPLC analysis. The optimum mobile phase... 

A gradient HPLC procedure with UV detection, for determination of pesticide residues in fruit and vegetables such as apples, potatoes, and carrots, was used by Beil et al. (57). Figure 3 shows a clean chromatogram of many compounds that was obtained by HPLC and UV detection in apple. 

A procedure for determining pesticide residues in fruit and vegetable (apples, potatoes, and carrots) using HPLC-UV detection has been reported. A monitoring study in which 40 samples of different origin were examined was carried out. a-Endosulfan was detected in one apple sample, and tetradifon was detected in a potato sample (57). 

Most HPLC applications used for phenolic analysis simply allow the room temperature to determine the operating temperature of the column, but elevated temperatures of between 30°C and 40°C are often applied for phenolics and derivatives in apples (14), carrots (15), apple juice (6,13), bilberry juice (16), and for cis-trans isomers of caffeic and p-coumaric acids in wines (17). Generally, a change in temperature has only a minor effect on band spacing in reversed-phase HPLC and has essentially no effect in normal-phase separations. Thermostatic control of the column temperature is generally recommended to provide reproducible retention. 

Marx, M., Schieber, A. and Carle, R. (2000) Quantitative determination of carotene stereoisomers in carrot juices and vitamin supplemented (ATBC) drinks . Food Chemistry 70(3), 403-8. 

Intermediary metabolism of irradiated tissues was examined to attempt to explain the increased respiration on the basis of biochemical mechanics. In these experiments carrot disks 0.5 mm. thick were prepared as before and subjected to substrate utilization studies (9). This involved incubating the slices with the appropriately labeled substrate in 0.03M phospate buffer at 25°C. The incubation involves shaking with gentle aeration and trapping the respired CO2 in alkali. Following incubation the slices were removed, washed, ground with 80% ethanol, and filtered, and both the filtrate and residue were assayed for radioactivity. Thus, a measure of substrate absorption and utilization was determined. 

Head-space gas chromatographic determination of isovaleraldehyde Dried carrot samples(0.5 g) were... 

The influence of the carrot variety on Maillard reaction Samples of six freeze-dried carrot varieties were equilibrated at room temperature to a water activity of 0.33 (J 7), corresponding to an average water content of 6.3 % (related to wet matter). Then the samples were heated to 55 °C for 30 h and the concentrations of Amadori compounds as well as the corresponding sensory changes were determined. The results are listed in Table IV. The amount of Amadori compounds formed by the heating process seems to be correlated... 

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