Yellow beet

Myzus persicaey the most important aphid vector is known to transmit over 100 plant viruses such as beet mild yellowing, beet yellow net, beet nrild yellows, pea enation mosaic, potato leaf roll, radish yellows, tobacco vein distorting, and tobacco yellow vein banding (4). As a result of their ingestion, excretion, and disease transmission, aphids could cause serious crop loss. 

Beet toots contain both ted pigments (betacyanins) and yellow pigments (betaxanthins), known collectively as betalains. Generally, the betacyanin content of beets fat exceeds that of the betaxanthins. Of the betacyanins present, 75—95% is betanin [7659-95-2] (41) (EEC No. E 162), making it the principal pigment ia beet colorant. 

Betalaines. In 1968, the term betalaines was used to describe collectively two groups of plant pigments the red betacyanins and the yellow betaxanthins. The red and yellow dyes found in beets. Beta vulgaris, fall into this category. An interesting history has been written about these dyes (133). 

The study of these fragments, coupled with the results of additional research (139), estabUshed the stmcture of betanin [7659-95-2] (50). Betanidin [37279-84-8] was synthesized in 1975 (140). A small amount of two yellow pigments is present also in beets (51). These have no value as food dyes. 

Stintzing, F.C., Schieber, A., and Carle, R., Identification of betalains from yellow beet (Beta vulgaris L.) and cactus pear (Opuntia ficus-indica (L.) Mill.) by high-performance liquid chromatography-electrospray ionization mass spectrometry, J. Agric. Food Chem., 50, 2302, 2002. 

Betalains have recently regained importance due to continuing interest in natural food colorants. Currently, red beet is the only food source commercially exploited, although amaranth, Swiss chard, yellow beet, and cactus fruit represent promising... 

Decarboxybetaiudin, the glucoside of which was reported recently in hairy root cultures of yellow beet, may be synthesized from dopamine. Two further alternatives were proposed earlier. While Minale and co-workers subjected betanin... 

While earlier papers cited buffer systems or aqueous o-phosphoric acid to achieve satisfactory peak resolution, most recent investigations involved acetic acid or formic acid systems. " Representative examples are 0.2% and 1% HCOOH for betacyanins and betaxanthins, respectively, the latter requiring a lower pH for chromatographic resolution. Methanol or acetonitrile are most commonly used as modifiers, either undiluted or diluted with purified water at ratios of 60 40 or 80 20 (v/v), respectively. - Typical HPLC fingerprints for yellow and red beet juice are shown in Figure 6.4.1. 

In a recently pnblished example of betaxanthin analyses in a complex food matrix, 19 betaxanthins were assigned in yellow Swiss chard petioles. Mass spectrometric measnrements are even more helpfnl if nnknown betacyanin structures are to be elucidated. While betacyanic plant materials such as red beet and amaranth may still be commercially available for coinjection experiments and comparison with samples under investigation, it may be an easier task to first optimize pigment separation followed by mass spectrometric measurements. 

Litmus is not the only plant material that turns a different color in response to acidic or basic conditions. For example, when red cabbage or beets are boiled, the solids can be separated from the liquid. The liquid is then cooled for use as an acid-base indicator. Red cabbage juice is red or purple in acidic conditions, while bases cause it to turn blue or yellow. When a solution is neutral, the juice is a bluish-purple. 

Kaufmann A, Koenig R, Lesemann D-E. Tissue print-immunoblotting reveals an uneven distribution of beet necrotic yellow vein and beet soil-borne viruses in sugar beet. Arch Virol 1992 126 329-335. 

Medium vitamin A and procarotenoids content (1,000-10,000 I. U./100 grams). Apricot, beet greens, broccoli, butter, chard, cheese (except cottage), cherry (sour), chicory, chives, collards, cream, eel. egg yolk, endive, fennel, kale, kidney (beef. pig. sheep), leek greens, lettuce (butterhead and romaine), liver (pork), mango, margarine, melons (yellow), milk (dried), mustard, nectarine, peach, pumpkin, squash (acorn, butternut, hnbhard), sweet potato, tomato, watercress, whitefish. 

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