Sugar and selected amino acid influences on the structure of pyrazines in microwave heat‐treated formulations

Abstract

AbstractThe amount and type of selected sugars and selected amino acids have been shown to significantly impact the structure of headspace‐volatile pyrazines produced in aqueous microwave heat‐treated formulations. Selection of sugar and amino acid can dictate the structure, yield and distribution of headspace‐volatile pyrazines. Under the same reaction conditions and sugar to ammonium hydroxide ratios, rhamnose was found to produce more pyrazines than did high‐fructose corn syrup (HFCS). With rhamnose, the yield of pyrazines approached 4500 µg mL−1. Formulations selectively enriched in ethyldimethylpyrazines can be prepared by stepwise substitution of HFCS with rhamnose. Formulations preferably enriched in methyl‐ and dimethyl‐(3‐methylbutyl)‐ as well as methyl‐ and dimethyl‐(2‐methylpropyl)pyrazines were prepared through selective combinations of rhamnose/HFCS and amino acids. Stepwise substitution of HFCS with rhamnose coupled with the use of selected amino acids allowed for the control of the yield, structure and distribution of volatile pyrazines in microwave heat‐treated aqueous formulations. Reaction temperature was also found to significantly influence pyrazine yield and distribution. Statistical modeling of the reaction yields as functions of reaction variables produced surfaces with acceptable modeling coefficients. Mechanisms were postulated to account for the increased yields and selected distributions pyrazines when rhamnose was employed. Copyright © 2005 Society of Chemical Industry