Spinach, greenness

This experiment provides students with the opportunity to isolate a biomolecule from its natural source, followed by its purification and identification. In addition, students will follow a procedure that is typical of the general extraction and characterization of lipids. However, unlike most lipids, the plant pigments are highly colored and may be characterized and quantified by visible spectrophotometry. Several types of plant tissue may be used. Some recommendations are fresh leaves (tree, plant, grass, spinach), green algae, or mosses. For variety, students may be asked to bring their own samples for analysis. 

In Table XLII are shown regression coefficients for raw vs. cooked carotene contents for four vegetables, spinach, green beans, Fordhook chard, and rhubarb chard. Details of the experiment are contained in the table. Two regression coefficients were calculated for each set of replications. Calculation of the regression for fresh value on cooked is based on the assumption that the cooked values were measured without error, and the regression of cooked values on fresh is based on the assumption that the fresh values are measured without error. One or the other of these assumptions is often convenient to make, even though neither is entirely correct. 

Reference Green grape Onion Leek Lettuce Broccoli Spinach Green cabbage... 

A dark green or deep yellow vegetable or a yellow Iruit foi vitamin A broccoli, spinach, greens, canteloupe, apricois, carrots, pumpkin. 

A chromatographic column filled in three sections with ground sugar, chalk, and alumina. When a petroleum extract of spinach leaves is run onto the top of the column, ihe extract spreads down the column, but not uniformly bands of green chlorophylls stop near the top. yellow xanthophyll further down, and red carotene near the bottom. 

Fertile sources of carotenoids include carrots and leafy green vegetables such as spinach. Tomatoes contain significant amounts of the red carotenoid, lycopene. Although lycopene has no vitamin A activity, it is a particularly efficient antioxidant (see Antioxidants). Oxidation of carotenoids to biologically inactive xanthophyUs represents an important degradation pathway for these compounds (56). 

In a Food and Dmg Administration (FDA) summary of the levels of pesticides in ready-to-eat foods in the 10-year period from 1982 to 1991, methyl parathion was found 12 times in 8 kinds of food, at an average concentration of 0.0035 ppm (Kan-Do Office and Pesticides Team 1995). A 5-year analysis of domestic and imported foods and animal feeds for the years 1982-1986 detected 94 samples out of 19,851 total samples that contained methyl parathion (Hundley et al. 1988). Eighty-nine of the samples had concentrations in the range of 0.05-0.5 ppm, and five had levels ranging from 1.0 to 2.0 ppm. Methyl parathion was found in celery, citms, coriander, cantaloupe, Chinese peas, hay, alfalfa feed, Italian squash, lettuce, mustard greens, okra, parsley, peppers, spinach, strawberries, tomatillos, and tomatoes. 

Fig. 6. Sequence comparisons of Rieske proteins from spinach chloroplasts, beef heart mitochondria, green sulfur bacteria, and firmicutes. The extended insertion of proteobacterial Rieske proteins as compared to the mitochondrial one is indicated by a dotted arrow. The redox-potential-influencing Ser residue is marked by a vertical arrow. The top and the bottom sequence numberings refer to the spinach and bovine proteins, respectively. Fully conserved residues are marked by dark shading, whereas the residues conserved in the b6f-group are denoted by lighter shading.

In a clinical trial performed in China, the administration of 300 mg/day of copper chlorophyllin to humans who had detectable levels of serum aflatoxin due to unavoidable food contamination resnlted in a 50% reduction of median urinary levels of aflatoxin-DNA adducts. If health benefits from consuming natural chlorophylls were confirmed, it wonld be easy to add green leafy vegetables to a daily diet to obtain the benefit. Since leafy vegetables contain usually up to 200 mg chloro-phylls/100 g fresh weight, the intake of approximately 1 to 2 cups of raw spinach/day... 

Diets high in red meat and low in green vegetables have been associated with increased colon cancer risk and the opposite has been postulated for diets rich in green vegetables. A plausible explanation for an increased colon cancer risk is that dietary haem is metabolized in the gut to a factor that increases colonic cytotoxicity and hyperproliferation, which are considered important risk factors in the development of cancer. In this sense, it has been shown that spinach and isolated natural chlorophyll, but not sodium-copper chlorophyUin, prevented the proliferation of colonic cells and may therefore reduce colon cancer risk. It has been speculated that haem and chlorophylls, due to their hydrophobicity, form a complex, thus preventing the metabolism of haem. ... 

Tomato, watermelon, pink grapefruit, papaya, guava, rose hip Carrot, apricot, mango, red pepper, kale, spinach, broccoli Carrot, collard green, pumpkin, corn, yellow pepper, cloudberry Kale, spinach, broccoli, pea, Brussels sprout, collard green, lettuce, corn, egg yolk... 

Carrots were also the main sonrces of a-carotene, whereas tomatoes and tomato prodncts were the major sources of lycopene. Lutein was mainly provided by peas in the Republic of Ireland and United Kingdom. Spinach was found to serve as the major source in other countries. Lutein and zeaxanthin xanthophylls are found in a wide variety of fruits and vegetables, particularly green leafy vegetables, but also in some animal products such as egg yolks. In all countries, P-cryptoxanthin was obtained primarily from citrus fruits. 

Nisha, R, Singhal, R.S., and Pandit, A.B., A study on the degradation kinetics of visual green colour in spinach (Spinacea oleracea L.) and the effect on salt therein, J. Food Eng., 64, 135, 2004. 

Added to extracts of mustard greens, celery, head lettuce, leaf lettuce, spinach, and tobacco only. 

Apple, pears, wheat forage, cantaloupe, cucumbers, squash, lettuce, mustard greens, plums, peaches, cherries, peanuts, potatoes, tomatoes, peppers, grapes, radish, carrots, tobacco, oranges, lemons, grapefruits, celery, spinach, cabbage Gas chromatography/mass spectrometry (GC/MS)... 

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