Potatoes dry matter

The characteristic most commonly used as an estimator of potato dry matter is specific gravity (Storey and Davies, 1992). Specific gravity of potato tubers can be determined using the formula ... 

The total solid (dry matter) content of potato can be obtained by freeze-drying. Dry matter content is determined from the difference in the weight of potato samples before and after freeze-drying. The potato dry matter can also be estimated from the specific gravity measurements. In recent years, near infrared (NIR) spectroscopy has been used to measure specific gravity of potatoes. The NIR spectra (700-1100 nm) of potato samples are acquired, and partial least squares (PLS) regression analysis can be used to develop a predictive model for specific gravity (Scanlon et al., 1999). 

Potato dry matter is ground to a powder using a mortar and pestle. To 100 mg potato dry matter, 100 p,L (300 U) of a-amylase (e.g. from Bacillus species. Sigma A-6380, St Louis,... 

Starch content of potato dry matter is calculated as follows ... 

In recent years, a new research method was developed to determine total starch content of potato dry matter by comparing the gelatinization enthalpy of potato dry matter and standard starch using differential scanning calorimetry (DSC) (Liu et al., 2005). 

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. 

The chemical composition of potato depends on many factors including genetic features, age and maturity, as well as enviromnental conditions, i.e., climatic and soil conditions, weather and growing conditions, such as fertilization, pesticides, diseases, etc. Table 31.1 shows the chemical composition of potato tuber. The potatoes are a considerably richer source of nutrient than energy. Starch is the basic component of potato dry matter, contributing the major amount of energy obtained by potato consumption. Potato contains... 

FIG. 4 Effects of varying raw material treatments prior to osmotic dehydration on moisture (MC) and solid (SC) content expressed on initial dry matter (idm). Potato slices, high hydrostatic pressure (Rastogi et al., 2001) carrot slices, PFE (Rastogi et al., 1999) bell pepper disks, PFE (Ade-Omowaye et al., 2002b) and apple slices, edible coatings (Lenart and Dabrowska, 1998). 

Data are not available for protein production worldwide. However, an estimate of the protein contribution provided by sweet potatoes can be made if we assume a mean dry matter content of 28% and a mean protein content of 5%. Based on these assumptions, the sweet potato provides 1.92 million metric tons of protein worldwide. The yield of protein would be 134 kg/ha using worldwide yield values or 184 kg/ha using US production values. 

Some 65-75% of the dry matter of the potato tuber consists of starch that is readily extractable in water (Burton, 1989). In early 19th century households in potato-growing areas it was... 

Ortega, R, Carraso, A. (2005). Germplasm enhancement with wild tuber-bearing species Introgression of PVY resistance and high dry matter content from Solarium berthaultii, S. gourlayi, S. tarijense, and S. vemei. Potato Research, 48,97-104. 

Dietary Reference Intake (DRI) of Cu, 17-18% of the DRI of K, P, and Fe, and between 5 and 13% of the DRI of Zn, Mg, and Mn (Table 5.1). Potatoes are generally not rich in Ca, but can be a valuable source of trace elements, such as Se and I, if fertilized appropriately (Eurola et al., 1989 Poggi et al., 2000 Turakainen et al., 2004 Broadley et al., 2006). Moreover, since potato tubers have relatively high concentrations of organic compounds that stimulate the absorption of mineral micronutrients by humans, such as ascorbate (vitamin C), protein cysteine and various organic and amino acids (USDA, 2006), and low concentrations of compounds that limit their absorption, such as phytate (0.11-0.27% dry matter Frossard et al., 2000 Phillippy et al., 2004) and oxalate (0.03% dry matter Bushway et al., 1984), the bioavailability of mineral elements in potatoes is potentially high. 

Workman, M., Holm, D. G. (1984). Potato clone variation in blackspot and soft rot susceptibility, redox potential, ascorbic acid, dry matter and potassium. Am. Potato J.,61, 723-733. 

Micronutrients do also affect potato quality and yield applications of B, Mn, and Zn increase the starch grain size, while applications of iodine or ammonium molybdate increase the dry matter and starch content. 

A wide variety of methods and instruments have been employed to control the quality of raw and processed potatoes. The key characteristics of importance for potatoes for processing are dry matter, reducing sugar content, color, size, and defects. The Potatopro Newsletter (2008) Food Innovation Online (http //www.foodinnovation.biz) shows equipment (Martin Lishman Ltd,... 

The dry matter of a potato is the major determinant of texture of the raw or cooked product (Thygesen et al., 2001) and texture, in turn, is the most important of the sensory attributes that contribute to favorable mouthfeel and consumer acceptance (Tam et al., 1992). 

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