Abstract
The
neutralisation of acid casein with a twin-screw cooking extruder was
studied using sodium bicarbonate as the neutralising agent. The effects
of sodium bicarbonate concentration, moisture content in the feed and
mass temperature on the properties of the product powder were tested. An
NaHCO3 concentration of 4% gave greater expansion ratios than did 2.3
or 6%. Moisture content in the feed in the range 20-30% did not have a
significant influence on the expansion ratio but had an effect on the
solubility of the ground product. With a moisture content of 20% in the
feed and an NaHCO3 concentration of 4% the solubility was 83%, whereas
with moisture contents of 23-29° it was 97-100%. The mass temperature
had a significantly greater influence on the expansion ratio than did
the moisture content. The expansion ratio increased with a decrease of
the mass temperature, reaching the highest value at 65-73°C within the
range tested. The Iysinoalanine concentration in the product remained
low ( < 30 μg/g) with an NaHCO3 concentration of 4%. a mass
temperature of 65-93°C and a moisture content of 20-30% in the feed. The
ground extrudate had a coarse structure which was less porous than that
of spray-dried powders. This gives the product a high particle density
and good dispersibility.
| Original language | English |
|---|---|
| Pages (from-to) | 443-447 |
| Journal | Lebensmittel-Wissenschaft & Technologie |
| Volume | 19 |
| Issue number | 6 |
| Publication status | Published - 1986 |
| MoE publication type | A1 Journal article-refereed |