Semi-Sweet Biscuits: 2. Alternatives to the Use of Sodium Metabisulphite in Semi-Sweet Biscuit Production

Abstract

The influence of sodium metabisulphite (SMS) and other gluten-modifying agents on the performance of a commercial biscuit flour in the production of semi-sweet biscuits has been studied. Use of a proteolytic enzyme as a gluten-modifying agent resulted in a dough with a longer mixing time than other doughs, partly as a result of mixing to a higher temperature. The extrusion time of doughs containing the proteolytic enzyme was closest to the extrusion time of doughs containing SMS. Doughs containing SMS or proteolytic enzyme produced significantly shorter extrusion times than doughs containing l-cysteine hydrochloride. Dynamic oscillatory measurements showed that for doughs made at a constant water level the lowest elastic and viscous moduli were produced by doughs containing sodium metabisulphite. Doughs containing the other gluten-modifying agents produced stronger elastic properties than those containing SMS but weaker elastic properties than doughs containing no gluten-modifying agent. The hardness of the semi-sweet biscuits produced was found to be reduced by a weakening of the rheological properties of the dough. All gluten-modifying agents reduced dough piece contraction in length during processing, although SMS was the most effective. A decrease in dough piece length during processing caused an increase in dough piece thickness and width. Use of a proteolytic enzyme or the enzyme and l-cysteine hydrochloride in combination, as gluten-modifying agents, produced biscuits closest in quality to those produced from doughs containing SMS.