VIEW ARTICLE    DOI: 10.1094/ASBCJ-53-0005

Effect of Sorghum Endosperm Type on the Quality of Adjuncts for the Brewing Industry. J. D. C. Figueroa, B. F. Martínez, and E. Ríos, CINVESTAV-IPN Depto. de Biotecnología y Bioingeniería, Alimentos, y Programa Multidisiplinario de Materiales Avanzados, Aptdo. Postal 14-740 México, D.F. 07000. J. Am. Soc. Brew. Chem. 53(1):5-9, 1995. Accepted June 9, 1994.

The performance of several genotypes of sorghum, corn, rice, and barley as adjunct material was investigated. The wort viscosity of waxy sorghum and waxy corn adjuncts was lower than that of floury or starchy sorghum, rice, and barley malt. The viscosity of sorghum adjunct worts varies from 1.42 cP for waxy endosperm to 1.48 cP for normal type endosperm, much lower than the corresponding value for barley malt wort (1.56 cP) under the same conditions. Waxy and heterowaxy materials had shorter conversion times than did normal sorghum. Studies of starch characteristics show that sorghum starches gelatinize at around 72°C, whereas barley gelatinizes at about 60.6°C. The waxy sorghum exhibited a lower gelatinization temperature (69.6°C) and higher peak viscosity (114 relative viscosity units) than that of the normal sorghum. A significant correlation was found among gelatinization temperature and conversion time and wort viscosity. High-performance liquid chromatography analyses revealed that the sugars present in sorghum, corn, rice, and barley malt worts are fructose, glucose, maltose, maltotriose, and maltotetraose. Peaks corresponding to glucose and fructose were absent or at trace levels in the chromatograms of diluted worts (6.5°P) of waxy and heterowaxy sorghum and of waxy corn, which seems to indicate that those adjuncts may produce a wort rich in complex carbohydrates and low in fermentable sugars. Keywords: Sorghum adjuncts, Starch gelatinization, Wort sugars