Novel Recovery of Malt Flavours from their Glycosidically Bound Precursors

By Hongnian Jin and P. Rogers BrewTech, Carlton and United Breweries Limited, Carlton, Australia. This poster was originally presented at the MBAA 112th Anniversary Convention, Keystone, Colorado, 1999.

Abstract
Sensory quality of alcoholic beverages may be enhanced if locked flavour components are released from their flavourless, glycosidic precursors. We have prepared malt glycosides from wort and demon- strated that intense flavours can be released after acid or enzyme hydrolysis, along with the formation of reducing sugars. The malt glycoside preparations have a pleasant but rather mild, worty and grassy nose in contrast to the strong fruity and varietal aroma associ- ated with similarly prepared grape glycosides. Acid treated malt glycosides released grassy and herbaceous aromas, and lacked the original worty character. Aroma released from grape glycosides by acid treatment was noticeably fruity and smoky. Prolonged acid treat- ment of the malt glycosides produced a pungent and spicy nose, which was also found in preparations of grape glycosides. Acid hydrolysed malt glycosides had a pleasant and appealing aroma, which was not evident in glucosidase treated samples. This was also true for grape glycosides. A large number of volatiles including many benzenoid compounds were generated from the malt glycosides upon treatment with either acid or glycosidase. Some of the volatiles are known flavour compounds; many have an unknown flavour role. It appears that the malt glycosides in many ways have similar charac- teristics to those found in grape glycosides. This may provide access to a new class of novel flavours from malt.
Keywords: Malt Glycosides, Glycosides Extraction  

Sintesis
La calidad sensorial de las bebidas alcoholicas puede ser aumentada si los componentes de sabores atrapados se liberan de sus precursores glicosidicos sin sabor. Nosotros hemos preparado glicosidos de malta del mosto y demostrado que se pueden liberar sabores intensos despues de la hidrolisis acida o enzimatica, asi coma la formation de azucares reductores. Las preparaciones de glucosido de malta tienen una agradable pero moderado olor a mostu y cesped en contraste al fuerte aroma de frutas asociado con los glicosidos de uva preparados similares. Los glicosidos de malta tratados con acido liberan aromas herbaceos y carecian del aroma de mosto original. El aroma liberado de glicosidos de uva mediante el tratamiento icido era notablemente a uvas y ahumado. El tratamiento prolongado de los glicosidos de malta produjo un aroma pungente y a especias, que tambien se encontro en preparaciones de giicdsidos de uva. Los glicosidos de malta hidrolizados con acido tenian un aroma placentero y atractivo el cual no era evidente en muestras tratadas con glicosidasa. Esto tambien se vio en glicdsidos de uva. Un gran numero volatiles, incluyendo muchos compuestos de benzenoide se generaron a partir de los glicosidos de malta al ser tratados con 6cido o glicosidasa. Algunos de los volsiles se recunocen coma compuestos de sabor, muchos tienen un papel desconocido en el sabor. Parece ser que los glicosidos de malta de muchas muestras tienen caracteristicas similares a esos encontrados en los glicosidos de uva. Esto puede proveer acceso a una nueva linea de sabores originales de malta.