Effects of Starch Amylose Content of Wheat on Textural Properties of White Salted Noodles

White salted noodles were prepared through reconstitution of fractionated flour components with blends of waxy and regular wheat starches to determine the effects of amylose content on textural properties of white salted noodles without interference of protein variation. As the proportion of waxy wheat starch increased from 0 to 52% in starch blends, there were increases in peak viscosity from 210 to 640 BU and decreases in peak temperature from 95.5 to 70.0°C. Water retention capacity of waxy wheat starches (80–81%) was much higher than that of regular wheat starch (55–62%). As the waxy wheat starch ratio increased in the starch blends, there were consistent decreases in hardness of cooked noodles prepared from reconstituted flours, no changes in springiness and increases in cohesiveness. White salted noodles produced from blends of regular and waxy wheat flours became softer as the proportion of waxy wheat flour increased, even when protein content of flour blends increased. Amylose content of starch correlated positively with hardness and negatively with cohesiveness of cooked white salted noodles. Protein content of flour blends correlated negatively with hardness of cooked noodles, which were prepared from blends of regular (10.5% protein) and waxy wheat flours (> 16.4% protein).     

Moisture Redistribution and Phase Transitions During Bread Staling

Standard white breads were stored with or without crust at 25°C in hermetic pouches. During two weeks of storage, the crumb moisture content and water activity (a_w) decreased significantly when stored with crust. When stored without crust, moisture content and a_w remained relatively unchanged. The causes of the initial firming of both breads over zero to seven days were not conclusive. But when stored beyond seven days, bread stored with crust was significantly firmer in texture and higher in amylopectin recrystallization than bread stored without crust. Moisture redistribution from crumb to crust played a significant role. This was accompanied by a decrease in freezable water in the bread crumb stored with crust. This loss in freezable water coincided with changes in the thermomechanical profile only in the case of sample stored with crust intact (and with a significant total and freezable water loss). Bread crumb stored without crust did not change in total and freezable water and showed less change in thermomechanical transitions. The transition occurring at ≈60°C (T₂) correlated with amylopectin recrystallization but it could also have been caused by moisture loss during the analysis. Moisture migration from crumb to crust greatly reduced the total and freezable water in the crumb region, resulting in a significant reduction in the magnitude of the mechanical transition at ≈0°C (T₁) as well as an increase in the storage modulus.     

Isolation and Characterization of Cotyledon Fibers from Peas,Lentils, and Chickpeas

Methods were developed to efficiently isolate legume cotyledon fibers with relatively high yields and purities. Seeds of pea (Pisum sativum), chickpea (Cicer arientinum), and lentil (Lens culinaris) were roller milled into flour and fractionated into prime starch, tailings starch, and water solubles. Insoluble dietary fiber was isolated from tailings starch by wet screening on sieves with openings ranging from 53 to 90 μm. Yield of insoluble fiber using a sieve with 53‐μm openings ranged from 49.7 to 59.2% of insoluble fiber in flour with purities ranging from 85.5 to 87.3%. Soluble dietary fiber was isolated from the water‐soluble fraction following acid precipitation of soluble protein at pH 4. Soluble fiber yield ranged from 83.3 to 89.6% of flour soluble fiber with purities ranging from 64.5 to 70.6%. Glucose was the most common sugar component of hulls and soluble cotyledon fibers, while arabinose was the main sugar in insoluble fibers. Insoluble fiber exhibited significantly higher swelling capacities and water and oil binding capacities in comparison to hulls and soluble cotyledon fibers. Apparent viscosities of soluble cotyledon fibers ranged from 3.13 to 3.43 Pa•sec and exhibited Newtonian characteristics.