No abstract

Cereal Chem. 74(2):141-146Garbanzo bean and pea flours originating from the central part of the cotyledons were higher in starch but lower in protein and fiber than those from the outer layer of the cotyledon. These flours were fractionated by the wet process into prime starch, tailing starch, and solubles. The patented wet-fractionation method was successfully modified to reduce the total amount of water during the process. The modified process produced comparable yield and purity of separated fractions. Under the recycling water method, the yields of prime starch were 46.7, 33.6, and 41.1%, respectively, in garbanzo bean and two smooth pea cultivars (Latah and SS Alaska). Isolated prime starches were <0.4% in protein and <0.19% in ash, indicating high purity.

Prime and tailings starches of garbanzo beans and peas were separated and the chemical composition, physical properties, thermal behavior, and gel properties were determined. Starch granules <35 μm were 85% in garbanzo beans, 66.8% in a smooth pea cv. Latah, and only 18.4% in a smooth pea cv. SS Alaska. Amylose content of prime starch was 35.9% in garbanzo beans, 44.5–48.8% in smooth peas, and 86.0% in wrinkled pea cv. Scout. Tailings starch amylose content was at least 8% higher than the corresponding prime starch. The endothermic enthalpy value of garbanzo bean and two smooth pea prime starches ranged from 12.1 to 14.2 J/g, while prime starch from wrinkled peas gave a distinctly lower enthalpy value of 1.1 J/g. Differential scanning calorimetry endothermic enthalpy and amylograph pasting properties of prime starch were significantly related to its amylose content (P < 0.05). Prime starches of garbanzo beans and smooth peas produced highly cohesive elastic gels. Wrinkled pea prime starch formed the strongest (though brittle) gel, as indicated by high hardness (21.8 N), low cohesiveness (0.29), and low springiness (0.82). Hardness of gel stored at 22°C and at 4°C was positively correlated with amylose content of starch.

Amylose contents of prime starches from nonwaxy and high‐amylose barley, determined by colorimetric method, were 24.6 and 48.7%, respectively, whereas waxy starch contained only a trace (0.04%) of amylose. There was little difference in isoamylase‐debranched amylopectin between nonwaxy and high‐amylose barley, whereas amylopectin from waxy barley had a significantly higher percentage of fraction with degree of polymerization < 15 (45%). The X‐ray diffraction pattern of waxy starch differed from nonwaxy and high‐amylose starches. Waxy starch had sharper peaks at 0.58, 0.51, 0.49, and 0.38 nm than nonwaxy and high‐amylose starches. The d‐spacing at 0.44 nm, characterizing the amylose‐lipids complex, was most evident for high‐amylose starch and was not observed in waxy starch. Differential scanning calorimetry (DSC) thermograms of prime starch from nonwaxy and high‐amylose barley exhibited two prominent transition peaks: the first was >60°C and corresponded to starch gelatinization; the second was >100°C and corresponded to the amylose‐lipid complex. Starch from waxy barley had only one endothermic gelatinization peak of amylopectin with an enthalpy value of 16.0 J/g. The retrogradation of gelatinized starch of three types of barley stored at 4°C showed that amylopectin recrystallization rates of nonwaxy and high‐amylose barley were comparable when recrystallization enthalpy was calculated based on the percentage of amylopectin. No amylopectin recrystallization peak was observed in waxy barley. Storage time had a strong influence on recrystallization of amylopectin. The enthalpy value for nonwaxy barley increased from 1.93 J/g after 24 hr of storage to 3.74 J/g after 120 hr. When gel was rescanned every 24 hr, a significant decrease in enthalpy was recorded. A highly statistically significant correlation (r = 0.991) between DSC values of retrograded starch of nonwaxy barley and gel hardness was obtained. The correlation between starch enthalpy value and gel hardness of starch concentrate indicates that gel texture is due mainly to its starch structure and functionality. The relationship between the properties of starch and starch concentrate may favor the application of barley starch concentrate without the necessity of using the wet fractionation process.

Cereal Chem. 77(4):507-511The highly variable environmental conditions across the Pacific Northwest (PNW) influence the milling and baking quality of wheat grain produced in this region. This study was conducted to compare the flour composition, dough rheology, and baking quality of soft and hard spring wheat grain produced in diverse environments. Thirteen soft and five hard spring wheat cultivars were grown at Lind, WA (semiarid) and Fairfield, WA (high precipitation) for three years. Grain was evaluated for flour composition, rheology, and experimental baked product quality. Flour composition, rheological properties, and baking qualities were primarily influenced by the environment. Protein contents, microSDS values, and water absorption levels were significantly (P < 0.0001) higher for all cultivars grown at Lind compared with those from Fairfield. Cookie diameters were larger (P < 0.0001) for soft flours from Fairfield, whereas loaf volumes were higher (P < 0.0001) for hard wheat flours from Lind. Results indicate that producing soft or hard wheat outside of its optimal climatic zone reduces experimental baked product quality.