Optimal Silver Nitrate Concentration to Inhibit α‐Amylase Activity During Pasting of Rice Flour. (6th November 2020)

• Record Type: Journal Article
• Authors: Rahman, Sayedur; Khoddami, Ali; Copeland, Les; Atwell, Brian J.; Roberts, Thomas H.
• Is Part Of: Stärke. Volume 73:Number 1/2(2021)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2020-11-06
• Subjects: alpha‐amylase -- Oryza sativa -- rice -- RVA -- silver nitrate; Starch -- Periodicals; 572.566
• DOI: 10.1002/star.202000150
• Languages: English
• ISSNs: 0038-9056

Abstract

Abstract: Endogenous α‐amylase interferes with accurate determination of the pasting properties of cereal flour. Silver nitrate (AgNO3 ) solutions at seven different concentrations (0.001‐0.1 m ) plus a deionized water (dH2 O) control are compared for their ability to inhibit α‐amylase activity during gelatinization of rice flour with medium to high amylose content (AC). Pasting properties are assessed using a Rapid Visco Analyzer (RVA). The optimal concentration of AgNO3 to inhibit α‐amylase in the flour of rice cultivar Doongara during gelatinization is 1% (w/v) (≈0.06 m ). This concentration is tested further in three other types of rice for confirmation of the effects on RVA pasting properties. Peak viscosity is significantly higher using 1% AgNO3 than in the dH2 O control, while breakdown and pasting temperature are significantly lower. In conclusion, the incorporation of 1% (w/v) AgNO3 into samples for RVA inhibits the α‐amylase activity in rice flour with medium to high AC, allowing pasting properties to be accurately measured using an RVA. Abstract : Endogenous α‐amylase activity inhibits accurate determination of pasting properties of cereal flour. Seven different concentrations of AgNO3 solutions are compared for their ability to inactivate α‐amylase activity during gelatinization of rice flour. The optimum concentration to inhibit α‐amylase activity during gelatinization is 1% (w/v) AgNO3 .