No abstract

The objective of the present study was attempted to develop a pregelatinized waxy rice flour (PWRF) retarding agent formulation by merging with α-amylase and monoglycerides, as well as using pregelatinizing and lyophilizing technologies to improve bread characteristics such as staling and retrogradation. The major methods, including texture profile analysis (TPA) and sensory evaluation were employed to assess bread qualities. Research results demonstrated the amylose complexing index (ACI) of the PWRF-adding bread samples were higher than that of groups α-amylase-adding, monoglycerides-adding and control. PWRF-adding bread samples exhibited higher starch digestibility and water activity (aw) and showed softer texture, lower hardness and soluble starch content than the groups α-amylase-adding, monoglycerides-adding and control after storage. The PWRF-D exhibited the best effect among all formulations. Further, either fresh or after storage PWRF-adding bread samples acquired the higher sensory score. The bread qualities were improved by PWRF and the staling and retrogradation were further retarded.

WanKao (rice curd) products, included control and added pregelatinized waxy rice flour (PWRF) retarding agent, were prepared and evaluated by texture profile analysis and sensory evaluation. The results showed that the amylose complexing index of the WanKao products contained PWRF were higher than the control, and directly added α‐amylase or monoglycerides. Upon storage, WanKao products contained PWRF showed higher water activity and starch digestibility than those added α‐amylase or monoglycerides. The hardness and soluble starch content of WanKao products contained PWRF were significant lower than those of added α‐amylase or monoglycerides and the control. The WanKao products added PWRF also exhibited softer texture during storage. For sensory evaluation, the higher score of was the added PWRF‐D (contains 100 g of waxy rice flour, 200 g of water, 6% of monoglycerides and 400 mg/kg of α‐amylase) WanKao product presented higher overall acceptability than that of added α‐amylase, monoglycerides, and control either fresh or after low‐temperature storage (5C for 5 days). As a result, the texture qualities of WanKao could be improved by the addition of the PWRF and also the staling and retrogradation rates were further retarded. PRACTICAL APPLICATIONS Taiwan's consumers demand for high quality WanKao products, i.e., softer, slow to staling and retrogradation, and good acceptability. Our results indicated that the qualities of WanKao could be improved by the addition of the novel retarding agent, PWRF, and the staling and retrogradation rates were further retarded.