Bacillus subtilis α-amylase was used to hydrolyze
starch from peeled and whole potatoes (Solanum tuberosum).
Effect of gelatinization temperature, pH, enzyme concentration,
temperature of hydrolysis and presence of calcium
ions were investigated. Optimum conditions for hydrolysis
were when α-amylase levels were 0.3 percent of the starch
concentration in the presence of 400 ppm calcium at pH 7.0
and 80°C for 2 hr. After centrifugation to remove residual
material, the supernatants were adjusted to pH 5.0 to 5.5
with 30 percent sulfuric acid and heated at 100°C for 10
min to inactivate α-amylase. Treatment with four percent
activated charcoal decolorized the clear hydrolysate before
the product was spray dried.
The dried product was a light yellow powder, slightly
sweet, relatively bland in taste and readily soluble in
water. Dried potato hydrolysate made from peeled potatoes
had a dextrose equivalent of 30 and contained 85 percent
carbohydrates, 8.4 percent protein and 5.5 percent ash;
while the hydrolysate from whole potatoes had a dextrose
equivalent of 26 and contained 86 percent carbohydrates,
8.4 percent protein and 6.0 percent ash. The composition
of the carbohydrates of the two hydrolysates were similar
except the hydrolysate from peeled contained a higher concentration
of glucose and lower concentration of saccharides
with a degree of polymerization greater than four.
At concentrations of greater than 40 percent, the
potato hydrolysate made from whole potatoes did not show as
high a viscosity as commercial corn syrup solids with a dextrose
equivalent of 24; the potato hydrolysate adsorbed
twice as much moisture as the commercial corn syrup solids
at 75 percent relative humidity at 23°C for 30 days.
Substitution of sucrose with whole potato hydrolysate
in chocolate milk revealed that substitution of two parts
of sucrose by two parts of potato hydrolysate could be used
with a slight loss of desirability. Fifty and one hundred
percent addition of whole potato hydrolysate to a commercial
dehydrated vegetable soup mix showed no decrease in
the desirability of the product.
This work has shown that a useful potato hydrolysate
containing significant amounts of protein can be prepared
from either peeled or whole potatoes. / Graduation date: 1978
| Identifer | oai:union.ndltd.org:ORGSU/oai:ir.library.oregonstate.edu:1957/27392 |
| Date | 16 June 1977 |
| Creators | Dondero, Marta Luisa |
| Contributors | Montgomery, Morris W. |
| Source Sets | Oregon State University |
| Language | en_US |
| Detected Language | English |
| Type | Thesis/Dissertation |
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