Potato processing peeling

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... 

In the northern part of Nigeria, sweet potato is processed into a local drink called kunuzaki. Fresh sweet potato is peeled, blended/grated or ground, sifted separated into boiled and unboiled portions, mixed, and left overnight to ferment and sugar added. 

Liquid by-product from potato processing, composed of peels and discarded pieces of potato (n= 15). 

Potato tubers are rich in starch and low in fibre, their ME value for pigs and poultry being 14-15 MJ/kg DM. Potato processing wastes (mainly peel) are higher in fibre than whole potatoes. 

Removal of the peel reduces the calystegine content by an average of over 50% in common potato varieties. Calystegines are water-soluble compounds and their leaching into water can be expected during potato processing. 

Pome Fruit Types. As with citrus fruit types, the method of sample preparation was modified for the parathion studies. In the earlier studies the DDT-treated apples and pears were scrubbed in a warm 10% solution of trisodium phosphate, and all the peel was removed from the water-rinsed fruit with a household-type potato peeler. The pooled samples of peel and pulp were then processed independently to recover the contained toxicant for subsequent estimation. 

Figure 3. Dehydrated Flakes Prepared from Fresh Peeled Yam Tubers by the SRRC-Sweet Potato Flaking Process.

Processing raw food reduced disulfoton levels in some potato products (Kleinschmidt 1971). Total residues were reduced by 35% with lye peeling. Lye peeling plus the first water blanching reduced the total disulfoton residue on a dry weight basis by 58, 74 and 61 % for french fries, dehydrated potato cubes and dehydrated mashed potatoes, respectively. 

Canned potato production constitutes just a small part of the overall market for processed potatoes. Production of chilled-peeled potatoes became established in Europe during 1995-2005 to supply a growing demand by restaurants, takeaways and the catering business. 

Figure 6.5 shows the structures of tra 5-cinnamic acid and four cinnamic acid derivatives (phenolic compounds) reported to be present in potatoes. Because potatoes are one of our major food plants, we validated with the aid of HPLC and LC/MS the content and distribution of antioxidative phenolic compounds in parts of the potato plant, in potato tubers, in the peel and flesh of tubers, in potatoes sold commercially in Korea and the United States, and in home-processed potatoes. The following discussion, based on our own studies, is followed by a brief overview of analytical methods for potato phenolic compounds by other investigators. 

The cited observations suggest that it is possible to identify potato cultivars with low or high phenolic acid content for human use and to select processing conditions that minimize losses of phenolic compounds. In summary, the methods we developed and used to determine the content and distribution of phenolic compounds in potato plant flowers, leaves, and tubers, in the peel and flesh parts of potato tubers, and in freeze-dried and processed commercial potatoes merit application in numerous studies designed to assess the role of potato phenolic compounds in host-plant resistance, plant breeding, plant molecular biology, food chemistry, nutrition, and medicine. The described wide distribution of phenolic compounds in different commercial... 

Kanatt, S. R., Chander, R., Radhakrishna, P., Sharma, A. (2005). Potato peel extract - a natural antioxidant for retarding lipid peroxidation in radiation processed lamb meat J. Agric. Food Chem., 53, 1499-1504. 

Garrote, R. L., Coutaz, V. R., Luna, J. A., Silva, E. R., Bertone, R. A. (1993). Optimizing processing conditions for chemical peeling of potatoes using response surface methodology. J. Food Sci., 58, 821-826. 

A Turkish study examined the effect of freeze-storing peeled, blanched then fried potatoes and found a 10% loss of vitamin C after 6 months of storage at — 18°C (Tosun and Yiicecan, 2008). However, a 51% loss was caused by the pre-freezing operations, which sounds a cautionary note about the importance of how potatoes are handled during processing. Some of our own... 

Most soft materials such as tomatoes, grapes or bananas are homogenised and then solvent extracted before further sample processing is carried out. However, material such as potatoes or apples have to be chopped first and the initial step can be Soxhlet extraction or homogenisation. Some materials (for example oranges or potatoes) may have to be peeled depending on whether the aim is to analyse the peel, the inner part of the food or the whole sample. 

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