Asparagus

Asparagus (Asparagus officinalis) is a fast growing crop high in folate and other nutrients. It is one of the best sources folate next to orange juice.  Folate keeps down blood levels of homocysteine, which is a culprit in atherosclerosis and heart disease. Folate is essential for pregnant women. Folate deficiency can lead to birth defects like neural tube disorders. Green asparagus (Asparagus officinalis) is a healthy and nutritious vegetable, containing antioxidants, such as rutin, ascorbic acid, tocopherol, ferulic acid and glutathione. Rutin accounts for an important percentage of the antioxidant activity in asparagus (Tsushida, Suzuki, & Kurogi, 1994). Among 23 commonly consumed vegetables, antioxidant activity of asparagus, based on dry weight, has been ranked as the greatest (Vinson, Hao, Su, & Zubik, 1998).

Rutin is a relatively heat-stable antioxidant compared to ascorbic acid in asparagus. Commercially canned asparagus contained 0.16 ± 0.01 mg/g wet weight of rutin, which was less than 42% of that in  fresh processed asparagus (Sun et al.,2007).

Asparagus also maintains digestive health by supplying a dose of fiber and a special carbohydrate called inulin.  This carbohydrate is indigestible to us, but readily consumed by intestinal bacteria. It promotes the growth of these beneficial bacteria, who in turn keep harmful gut bacteria at bay.

Asparagus deteriorates rapidly after harvest and becomes more fibrous with the development of a bitter flavour. It is, therefore, important to handle and process fresh asparagus quickly, to reduce the post-harvest losses and increase the economic return for farmers. Asparagus is preserved by canning, pickling, freezing and drying.

Rutin

Green  asparagus is a rich source of rutin (quercetin-3-rhamosylglucoside),  a flavanoid. The  levels of rutin in green asparagus shoot normally range from 0.03% to  0.06% on fresh weight basis.  Rutin  is a potent antioxidant and a scavenger of free radicals. Rutin has  been reported to possess certain beneficial biological activities which  include:

• Anti-lipoperoxidant
• Reduction  of oxidative damage
• Anti-inflammation

Protodioscin

On average, fresh  asparagus shoots contain 0.24 (tip portion) to 25 mg (base partion)  per 100 g fresh weight of protodioscin. The levels of protodioscin in  the crowns are around 25 mg/100g fresh weight.

Protodioscin has  been reported to possess the following bioactivities:

• Cytotoxicity against  a number of human cencer cell lines
• Reduction in bone  loss
• Improving sexual  performance

References

• Sun, T., Tang, J., & Powers, J. R. (2007). Antioxidant activity and quality of asparagus affected by microwave-circulated water combination and conventional sterilization. Food Chemistry. 100 (2), 813-819.
• Tsushida, T., Suzuki, M., & Kurogi, M. (1994). Evaluation of antioxidant activity of vegetable extracts and determination of some active compounds. Journal of the Japanese Society for Food Science and Technology-Nippon Shokuhin Kagaku Kogaku Kaishi, 41(9), 611–618.
• Vinson, J. A., Hao, Y., Su, X. H., & Zubik, L. (1998). Phenol antioxidant quantity and quality in foods: vegetables. Journal of Agricultural and Food Chemistry, 46(9), 3630–3634.
• Rutgers, 2009. http://aesop.rutgers.edu/~asparagus/program/health.html