Abstract
The objective of this study was to determine the impact of annealing and enzyme extract on the gel properties of chickpea (C.P), corn (C.S), Turkish bean (T.B), sweet potato (S.P.S), and wheat starches (W.S). Starches were annealed at different temperatures and times in excess water with or without germinated sorghum extract (GSE). The concentration of α-amylase in the GSE was 5 mg/10 mL. Dynamic rheological properties, freeze-thaw stability and water holding capacity (WHC) were investigated. The dynamic rheological parameters of the native or GSE-treated starches varied significantly (p < 0.05), while the G` of some starches were frequency-independent others exhibited sharp increase in G` at low frequencies. Unlike T.B and S.P.S, the G` of the native C.P and C.S starches was significantly (p < 0.05) reduced by annealing, whereas GSE-treatment reduced G` of all gels regardless of annealing temperature or time. Starch gels demonstrated significant (p<0.05) reduction in freeze thaw stability and increase in water holding capacity after annealing and GSE treatment.
Highlights
Starch is primarily two major molecules, amylose (AM) and amylopectin (AP) build of D-glucose
Amylose is a linear polymer of glucose linked by α-1-4 glycosidic bond, while amylopectin is branched α-1-6 glycosidic bond in addition to α-1-4 glycosidic
The objectives of this work were to estimate the concentration of α–amylase in the germinated sorghum extract (GSE) and determine the effect of annealing and crude GSE on the rheological, water holding capacity, and freeze-thaw stability of legume, tuber and cereal starches under different annealing conditions
Summary
Starch is primarily two major molecules, amylose (AM) and amylopectin (AP) build of D-glucose. Native starch utilization is limited because of gel instability “retrogradation” during storage. This property can be addressed by physical, chemical or enzymatic modifications. It is critical to maximize the process and reduce the cost of bioconversion (use of enzymes) of starch to glucose, ingredients or fuel (LopezRubio et al, 2008). Endo-acting α-amylase from different sources hydrolyses α-(1-4) bonds in a random manner, thereby initiates starch granule attack and reduces its molecular weight (amylose and amylopectin). The rate of hydrolysis of starch by α-amylase is complex and depends on the granule size, integrity, crystallinity, porosity, amylose content, and granule structure (Copeland et al, 2009)
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
