Abstract:

The chemical composition of Elaeagnus mollis seed kernels was preliminarily analyzed. Then, several common
methods for extracting plant proteins were compared to establish a more efficient method to extract protein isolates from
Elaeagnus mollis seed kernels. Alkaline extraction and acid precipitation was selected for higher extraction efficiency,
and the extraction parameters were optimized using one-factor-at-a-time method and orthogonal array design. Moreover,
a systematic investigation was carried out to evaluate functional properties of protein isolates. The results showed that
E. mollis seed kernels contained 50.87% crude fat, 36.27% protein, 2.91% starch, 5.50% water and 3.10% ash. The optimal
parameters for extraction were determined as follows: pH, 11.0; S/L ratio, 1:50 (g/mL); extraction temperature, 55 ℃;
extraction time, 2.0 h; and two extraction cycles. Under these conditions, the extraction yield of protein was 93.85% with a
purity of 84.81%. The water-holding capacity and oil-absorbing capacity of the proteins extracted ranged from 1.2 to 1.8 g/g
and 2.8 to 3.3 g/g, respectively. The foaming capacity and the emulsifying capacity could reach 190% and 25 m2/g under
optimum pH conditions.

Key words: Elaeagnus mollis seed kernel, protein, extraction process, functional properties