Potatoes proteins

The initial report on the nature of sweet potato protein indicated that most of the protein was a globulin "ipomoein"... 

Sweet potato protein is unequally distributed within the... 

It would appear that commercial quantities of sweet potato protein might be readily available as a by-product of the starch industry. The laboratory concentrates were bland, light-colored powders containing 80-88% protein. 

Feeding studies. Although sweet potatoes are a significant source of calories in many parts of the world, very little information is available concerning the nutritional quality of sweet potato protein as determined by controlled feeding studies in humans. 

Research by other workers ( 2, 33.) also suggested the sweet potato protein is readily utilized by humans. 

A report by Bressani et al. (3J7), which evaluated the nutritional value of diets based on starchy foods and beans, indicated that for the rat, sweet potato protein was of poor nutritional quality. When methionine was added to all diets to raise sulfur amino acids, sweet potato still required the largest amount of supplementation with bean flour to maintain animal weight (Table II). 

The literature on concentrated sweet potato protein is sparse. Amino acid patterns for sweet potato protein isolates have been reported by three groups (16, 45, 46). One report showed that when compared to the FAO standard (47), no amino acids were limiting. The other reports showed total sulfur amino acids and lysine to be limiting (Table III). The patterns indicate a nutritionally well balanced protein. The improvement in nutritional quality, when compared to amino acid patterns from whole sweet potato, is due to the fact that whole sweet potatoes contain substantial amounts of NPN, which consists mainly of nonessential amino acids. This effectively dilutes the EAA and lowers the amino acid score. 

Feeding studies with the rat as the test animal verified the high nutritional quality indicated by the amino acid pattern (45). Using isolates and concentrates prepared from Jewel and Centennial cultivars, PER values were equal to that of casein (milk protein) (Table IV). Examination of the amino acid patterns of sweet potato protein and casein revealed that both contained... 

Figure 5.1 Two-dimensional electrophoresis separates potato proteins based on their isoelectric points and molecular weights. Using a wide-scale pH gradient and large gels, 1000-2000 quantifiable proteins can be separated. The gel stained with SYPRO Rubi shows soluble tuber proteins of potato cultivar Sante.

Claussen, . C., Str0mmen,l.,Egelandsdal,B., Straetkvern, K. O. (2007). Effects ofdrying methods on functionality of a native potato protein concentrate. Drying Technology, 25, 1091-1098. 

FLEXNEWS. (2007). Interview Avebe s Solanie innovates with unique food ingredients, potato proteins. (23/04/2007). (http //www.flex-news-food.eom/eonsole/PageViewer.aspx page=8346 print=yes). 

Lokra, S., Helland, M. H., Claussen, I. C., Straetkvern, K. O., Egelandsdal, B.10.1016/j.lwt.2007.07.006 (2007). Chemical characterization and functional properties of a potato protein concentrate prepared by large-scale expanded bed adsorption chromatography. LWT - Food Sci. Technol. 

---