FOR Aspergillus niger M2 AMYLASE PRODUCTION WITH SOILD·STAT FEMENTATlON AND TO BE USED IN BREAD STALING EVALUATION. | ||
| Journal of Agricultural Chemistry and Biotechnology | ||
| Article 2, Volume 30, Issue 9, September 2005, Pages 5493-5514 PDF (250.97 K) | ||
| Document Type: Original Article | ||
| DOI: 10.21608/jacb.2005.238010 | ||
| Authors | ||
| S.M. Mansour1; EI. A. Mobarak2; A.H. Fahmy2 | ||
| 1Microbiol. Dept., Soil, Water and Environ. Res. Institute, Agric. Res. Center, Giza, Egypt. | ||
| 2Food Techno!., Res. Institute, Agric. Res. Center, Giza, Egypt. | ||
| Abstract | ||
| Because of the increasing demand on starch.hydrolyzing enzymes, this study was focused on studying factors controlling the production of c-arnylase, p. amylase and glucoamylase from Aspergillus niger M2 and also to study the effect of these enzyme on quality of balady bread and its staling properties. Spent brewing grain (SBG). was used as a solid substrate for the production of these enzymes. Different agro-industrial by-producls were tested for the production of a. p and glucoamylase. Maximum amylases yields, n, p and glucoamylase synthesis by A. niger Mz strain were 770. 390 and 950 IU/g dry substrate (g/ds), respectively. These values were obtained on the optimized media after 96 hrs and suitable conditions of initial moisture, inoculum size, initial pH and incubation temperature of 65%, 105 spores/gds, 5.0 and 30 "C, respectively. Maltose induced the enzymes biosynthesis and glucose syrup supported the enzymes formation. Amylases production were stimulated at 3.0% of glucose syrup. Corn steep liquor (CSL) at 0.21 % as N gave highest amount of these enzymes. Regarding the dururn wheat starches susceptibility to A. niger M, glucoamylase enzyme, it was lower than that of soft wheat starches. This may be due to the highest amylose lipid complexes in durum wheat starch. Organoliptic evaluation indicated that, durum bread has higher total scores being 87- 97% as compared with soft wheat bread which was 85-86%.Also durum bread has 95·100% of freshness scores, while soft wheat bread has 85-90% of freshness scores, after' hr of baking. Staling properties expressed as the result of hydrolysis of crumb bread with A. niger ~ •. h glucoamylase indicated that, after 72 hrs of storage at room temperature, hydrolysis was in the range of (126.8-137.7 mg gtucose/g crumb). and (94 ., 07.6 mg glucose/g crumb) in durum and soft bread crumb. respectively. This means that durum bread has longer shelf life and lower ability to staling mechanism due to its high content of amylopectin and amylose- lipid-complex. | ||
| Keywords | ||
| Solid substrate fermentation; Aspergillus niger; spent brewing grain and glucoamylase biosynthesis; staling evaluation | ||
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