Extraction, Purification and Characterization of Apricot Seed β-Galactosidase for Producing Free Lactose Cheese

Abstract

Abstractβ-Galactosidase was extracted (with acetate buffer pH 5) from apricot seeds, partially purified by ammonium sulphate (30-70%) and dialyzed for 24 hr. The crude extract had a higher specific activity (9.93 U/mg proteins) which indicates a high enzyme yield. Purification of crude extract with ammonium sulphate (30-70%) increased the specific activity and purification fold to 29.07 U/mg proteins and 2.92, respectively which was improved by dialysis to 32.68 U/mg proteins and 3.29, respectively. The extracted enzyme exhibits an optimum temperature at 70°C and 5 pH optima. The enzyme activity was almost stable between pH 5.0 and 6.5, where more than 90% of its activity was remained with incubation at the previous pH for 30 min. Further more; it was thermostable when incubated for 30 min. at temperature ranges of 55-70°C with a complete loss of activity at 80°C. The activity of β-galactosidase was enhanced by different concentration of Ca +2 . There were no significant (P>0.05) changes in flavor, body texture, and overall acceptability between free lactose white cheese treated by apricot seeds β -galactosidase (9865 U/ 500 ml milk) and untreated cheese.

Extraction and Purification of Β-Galactosidase From (Ziziphus Spina-Christi)

“…The molecular weight determined with the gel filtration and SDS-PAGE confirms monomeric nature of the β-galactosidase from (Ziziphus spina-christi). This result was approximately similar to the result of [17], on chick pea with a molecular weight of 83 kD, and with study of [1]. on Aspergillus niger 76 kD, but it was lower or higher in other studies 42 kD [2], 52 kD [21], 165.98 kD [19].…”

“…It was discovered that extracting 3 iso-enzymes of the β galactosidase from the apricots had an optimal val-ue of the pH from 4 to 6 [12], in almonds has been 5.50 and from black bean was 4.5 [14]. While the optimal value of the pH of the β-galactosidase was more acidic from chick pea seeds with 2.8 [17], and from peach was 3.0 [2].…”

“…It was purified from a variety of the sources of plants, such as mango [15], chick peas [17], almonds [13]Vigna unguiculata [18], apricot [19], tomato [2], watermelon [20], Peach [2] and cowpea [21]. Increasing the activity of the β-galactosidase throughout the germination of the seeds has been discovered as well in the plants like the soybeans and fenugreek [22] The plant β-galactosidase is more suitable for the industrial applications due to its easy adaptability high availability, as well as cost effectiveness [23].…”

“…It was discovered that extracting 3 iso-enzymes of the β galactosidase from the apricots had an optimal val-ue of the pH from 4 to 6[12], in almonds has been 5.50 and from black bean was 4.5[14]. While the optimal value of the pH of the β-galactosidase was more acidic from chick pea seeds with 2.8[17], and from peach was 3.0 [2].Purification of β-galactosidase: For purifying β-galactosidase, the crude extract has been precipitated using ammonium sulfate in different saturation ratios (30-90%), and dialyzed against poly ethylene glycol (M wt. 20000) overnight to remove an extra salt.…”