Impact of tempeh flour supplementation on the properties of non-gluten pasta product

Gluten-free products are needed by people with gluten allergy such as celiac disease and autism. The consumption of gluten-free products rises annually and, therefore, there is potential in the development of gluten-free products. Most of the non-gluten pasta products (NGP) contain a low amount of protein. In this study, NGP prepared from modified cassava flour (mocaf) (40%), rice flour (35%), and maize flour (25%), was supplemented with tempeh flour as a source of protein. In this research, NGP was prepared by extrusion. The cooked dough was extruded using a single screw extruder (screw diameter, 60 mm, locally manufactured by the Research Centre for Appropriate Technology-Indonesian Institute of Sciences, Subang, West Java Indonesia). The procedure of making NGP involved mixing all ingredients, steaming, extrusion, tempering, drying, and packaging. The effect of tempeh flour supplementation (0%, 2.5%, 5%, 7.5%, 10%, 12.5%, and 15% (w/w)) on the properties of NGP product was evaluated. The parameters of NGP that were evaluated included chemical properties, texture profile, elongation break, cooking properties, crystallinity structure, and morphological properties. The chemical properties included proximate and mineral content (iron (Fe) and zinc (Zn)) analysis. Results showed that adding tempeh flour significantly increased the protein, fat, fibre, iron, and zinc contents of NGP. The NGP had a moisture content of approximately 10%–12%. The higher tempeh flour addition resulted in the higher protein, lipid, Fe, and Zn contents of NGP. The highest protein and minerals (Fe and Zn) were obtained by 15% tempeh flour addition. Adding a higher amount of tempeh flour induced the higher percentage of V-type crystalline structure of amylose–lipid complex. Higher supplementation of tempeh flour resulted in higher cooking loss and decreased adhesiveness, springiness, and cohesiveness of the NGP product. The range of cooking time of NGP was between 5 min 25 sec and 6 min 50 sec. The supplementation of tempeh flour in the NGP reduced the cooking time. Observation of the morphological properties showed that starch of NGP ingredients had been fully gelatinized during the extrusion process as indicated by absence of intact starch granules.  Based on the results, it is suggested to supplement NGP with tempeh flour up to 10% (w/w) to get the nutritional advantage of tempeh without depressing its textural and cooking qualities