Jyotsna Rajiv

Scanning electron microscopic and electrophoretic studies of the baking process of south Indian parotta—an unleavened flat bread

The changes that take place in starch and protein molecules during processing of parotta, starting from wheat flour to baked parotta, were followed by scanning electron microscopy (SEM) and electrophoresis. The microstructure of wheat flour showed that the protein matrix was broken up into aggregates and starch granules were embedded in it. At the processing stage of parotta dough into a very thin sheet, the surface of dough appeared as a fine matrix of proteins and soluble solids with dispersed starch granules. The surface of baked parotta showed a still finer distribution of all the components. The microstructure of outer and middle layers of parotta showed clear differences. In the outer layer, starch granules were distorted and embedded in the protein matrix owing to the differential heating process whereas, in the middle layer, the extent of starch granule distortion was less than in the outer layer. Electrophoretic patterns of wheat flour, parotta dough and baked parotta revealed that less intense bands were observed in HMW regions of baked parotta. SEM and electrophoresis were found to be valuable tools for understanding molecular interactions between starch and protein molecules during the baking process of parotta.

Effect of co-milled wheat, green gram and barley on the rheological and quality characteristics of cookies.

Studies were carried out on the co-milling of wheat (W), green gram (GG) and barley (BR) grains using a roller milling system. The co-milled straight run flours obtained by varying proportions of wheat, barley and green gram WGGBR-1 (90:5:5), WGGBR-2 (80:10:10) and WGGBR-3 (70:15:15) were used in the cookie baking experiments. As the amount of GG and BR increased in blend, water absorption increased (56.5–58.4%) and dough stability and extensibility values decreased (104–92 mm). Hardness of cookie doughs and spread ratio (7.70–6.00) of cookies decreased and breaking strength values increased from 2900 to 3700 g in cookies made using co-milled blends WGGBR-1, WGGBR-2 and WGGBR-3. The highest breaking strength value (3700 g), large islands, gummy mouth feel and lowest overall quality score of 51.5 were recorded for cookies made with blend WGGBR-3 indicating that the cookies had unacceptable hard texture. The optimum blend for cookies was WGGBR-2 (80:10:10) and the cookies possessed slightly small islands, crisp, light texture and a pleasant taste. These cookies had 12.30 and 8.00% protein and dietary fibre as against the control cookie values of 8 and 4%, respectively. The in vitro protein digestibility of the control cookies was 61% and it was 51% for cookies made with WGGBR-2 blend.