45C-1 |
Analysis of factors that influence thiosulfinate profiles in minced Allium tissues |
Q. REN and K. L. Parkin. Dept. of Food Science, Univ. of Wisconsin, Madison, 1605 Linden Dr., A-109 Babcock Hall, Madison, WI 53706-1519 The characteristic flavors associated with freshly minced Alliums are conferred by thiosulfinates (TS) and related organosulfur compounds. The profile of TS evolving in Allium preparations is dependent on the alkyl-cysteine sulfoxide (ACSO) substrate profile and the characteristics of the native alliinase in the host tissue. In onion, alliinase action on 1-propenyl-CSO typically yields the 1-propenyl sulfenic acid (PecSOH)/propanethial-S-oxide (lachrymatory factor, LF), which is pungent, volatile and objectionable to some consumers. TS and related compounds are also believed to confer health-promoting bioactivities. Thus, efforts to minimize losses of LF and remove objectionable flavors would be conducive to expanded consumption of Alliums and dietary delivery of any associated health benefits. The objective was to determine suitable conditions for trapping PecSOH/ LF derived from alliinase action on 1-PecSO, as discrete TS species, based on the exploitation of a RSOH/TS alkanesulfenic acid-exchange reaction identified previously in our laboratory. Both model reaction systems and tissue-based systems were used in this study. Control was exerted over alliinase source, pH, levels/profiles of ACSO, levels and species of pre-formed TS, and the blending of one tissue preparation with another. Resulting TS/LF profiles were detected by HPLC. Leek alliinase favored the trapping of 1-propenyl groups as TS greater than other tissue alliinases. In contrast, onion alliinase favored LF as the most abundant product. Modulation of ACSO levels and pH caused more subtle changes in TS/LF profiles. Slightly acidic conditions (pH 5) favored trapping of 1-propenyl groups as TS and suppressed LF accumulation. In general, greater levels of pre-formed TS combined with limited rates of alliinase/ACSO reaction, favored trapping of PecSOH as TS. Results from this work research indicate that simple yet novel processing protocols are effective tools for manipulating TS/LF profiles in freshly minced Allium preparations for improved quality.
Session 45C, Food Chemistry: Flavor and aroma chemistry
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