Potato fibers

There is evidence that protease inhibitors selectively regulate the activity of specific digestive enzymes at the level of gene expression (Rosewicz et al., 1989). Specifically, soybean trypsin inhibitor increases secretion of proteases, including a form of trypsin that is resistant to inhibition but does not cause an increase in amylase secretion. Although the relationships between protease inhibitors and exocrine pancreatic secretion have received the most attention, pancreatic secretion is increased when potato fiber is added to the diet (Jacob et al., 2000), although the mechanism and signaling pathway have not been elucidated. 

Monosaccharide Sweet potato fiber, starch residues of sweet potato, cassava, potato HPAEC PAD (Au) [78]... 

The development of a by-production system could further minimize the cost of such plant-derived products. For example, potatoes are the raw material for the production of technical grade starch. During this process, soluble proteins are separated by heat treatment and sold as animal fodder. Recombinant proteins could be produced in transgenic potato tubers as a by-product of starch extraction, and this would be useful for proteins produced in large amounts with a low commercial impact, like structural fiber proteins. 

The levels of antifeedants can be raised safely only in plants such as forest trees or fiber crops, not in food plants for humans or livestock. Such problems have arisen inadvertently. For instance, a new insect-resistant potato cultivarhad to be withdrawn from the market because it contained high levels of the carcinogens solanine and chaconine (Renwick etal, 1984). In another example, an insect-resistant celery had 10 times the usual concentration of the carcinogen 8-methoxypsoralen (and related psoralens), which caused dermatitis in produce handlers (Seligman etal, 1987). 

The bulk of potato tubers is made up of parenchyma cells that have thin, non-lignified, primary cell walls (Reeve et al., 1971 Bush et al, 1999, 2001 Parker et al., 2001). Unless stated to the contrary, potato cell walls refers to parenchyma cell walls. These walls and their component polysaccharides are important for a number of reasons they form part of the total intake of dietary fiber, influence the texture of cooked potato tubers and form much of the waste pulp that is produced in large amounts by the potato starch industry when starch is isolated. The pulp is usually used as cattle feed, but potentially could be processed in a variety of ways to increase its value (Mayer, 1998). For example, the whole cell-wall residues could be used as afood ingredient to alter food texture and to increase its dietary-fiber content, or cell-wall polysaccharides could be extracted and used in a similar way or for various industrial applications (Turquois et al., 1999 Dufresne et al, 2000 Harris and Smith, 2006 Kaack et al., 2006). 

In addition to the walls of the parenchyma cells, the walls of the periderm (skin) cork cells form part of the total intake of dietary fiber and a waste product of potato processing for food as well as for starch. Although much is known about the suberin present in these cell walls (Bernards, 2002 Franke and Schreiber, 2007 Grafos and Santos, 2007), little is known about their polysaccharides (Harris et al., 1991). Nonetheless, because of the presence of suberin, these cell walls are able to adsorb hydrophobic dietary carcinogens and their intake may be important in the prevention of colorectal cancer (Harris et al., 1991 Ferguson and Harris, 1998, 2001). 

Kirby, A. R., Ng, A., Waldron, K. W., Morris, V. J. (2006). AFM investigations of cellulose fibers in Bintje potato (Solanum tuberosum L.) cell wall fragments. Food Biophysics, 1,163-167. 

Total dietary fiber (TDF) content of potato dry matter is determined according to the AACC (2000) method 32-05 following the total dietary fiber assay procedure (Megazyme k-TDFR 01/05). This is a gravimetric method that is simpler and faster than other analysis methods. In addition to total dietary fiber content, both soluble and insoluble dietary fiber content can be determined by this method. 

Relevance to potatoes Potatoes have thin cell walls so are not rich in NSPs. They are a valuable source of carbohydrate energy, but would not on their own provide enough dietary fiber to meet daily requirements. Increasing RS levels partially compensates for the low dietary fiber content of potatoes. 

Relevance to potatoes Dietary fiber includes cell wall NSP and RS, as both are digestion-resistant polysaccharides and both enter the colon where they may contribute to colonic health. NSP is low in potatoes but with RS formation NSP + RS (= dietary fiber) in potatoes can reach levels that allow the nutrient claim high in dietary fiber. ... 

Potato peels are waste by-products of the potato-processing industry. They are a good source of vitamin C, vitamin Be, copper, potassium, manganese, and dietary fiber. They also contain a... 

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