Carrots sulfiting

Preservatives. Sulfur compounds, such as sulfur dioxide and sodium bisulfite, are used commercially to preserve the color of various food products, such as orange juice, dehydiated fruits and vegetables, such as apricots, carrots, peaches, pears, potatoes, and many odiers. Concentrated sulfur dioxide is used in wine-making to destroy certain bacteria. The color preservation of canned green beans and peas is enhanced by dipping the produce in a sulfite solution prior to canning. In 1986, some of these compounds and uses were put under closer regulation in the United States. 

The existence of sulfite oxidase in plants snch as Arabidopsis thaliana (wall or thule cress), tobacco, pea, spinach, barley, carrot, and poplar trees has now been confirmed, and the enzyme from A. thaliana has been structurally characterized. The homodimeric, peroxisomal enzyme lacks the heme domain observed in animal sulfite oxidases, making it the simplest Mo-MPT enzyme yet isolated from eukarya. The animal and plant sulfite oxidases have an overall 47% sequence identity. The detoxification of sulfite, produced in the assimilation of sulfate into sulfur-containing amino acids and membrane components (sulfatides) and from environmental sources (acid rain), is also the principal role of the plant enzymes. 

ZHAO Y p and chang k c (1995), Sulfite and starch affect color and carotenoids of dehydrated carrots (Daucus carota) during storage , J Food Sci, 60, 324-326, 347. 

Sulfur dioxide was found to have a pronounced protective effect on carotenoids of unblanched carrots during dehydration [72]. Dehydrated, sulfited, unblanched carrots contained about 2.9 times more carotenoids than dehydrated unblanched carrots that had not been sulfited (Table 29.10). Treatment with SO2 gave additional protection to carotenoids of blanched carrots during dehydration and effectiveness of SO2 increased with an inaease in SO2 content. 

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