The effects of ambient temperature during the grain-filling period on the composition and properties of starch from four barley genotypes

• Published in: Journal of cereal science Vol. 13; no. 2; pp. 113 - 127
• Main Authors: Tester, R.F., South, J.B., Morrison, W.R., Ellis, R.P.
• Format: Journal Article
• Language: English
• Published: Kidlington Elsevier Ltd 01.03.1991; Elsevier
• Subjects: Biological and medical sciences; Medical sciences; Surgery (general aspects). Transplantations, organ and tissue grafts. Graft diseases; Surgery of the eye and orbit; FFA; TGW; CL; LPL; SF(AP); AM; DP; GT; AP; T 0, T p and T c; Δ H; FAME; SF; DSC; GPC; HPLC; Thermal stress; Barley; Temperature; Starch; Grain filling; Chemical composition; Physicochemical properties
• ISSN: 0733-5210; 1095-9963
• DOI: 10.1016/S0733-5210(09)80029-5

Starch was isolated from four genotypes of barley (one waxy, two normal and one high-amylose) grown at constant ambient temperatures of 10, 15, and 20 °C. There was evidence of physiological stress in grain grown at the higher temperatures, notably reduced starch accumulation, smaller A- and B-granules and fewer B-granules. In the waxy and normal genotypes amylose (AM) and amylopectin (AP) contents were little affected by increasing ambient temperature, but the lipid contents of the starches did show a strong response. No differences in the fine structure of AP in response to temperature were detected. Starch gelatinization temperatures (GT) were 50–55 °C, 52–62 °C and 60–63 °C in starches from grain grown at 10, 15 and 20 °C, respectively. Since the native starches could all be annealed to give similar elevated GT values (72–73 °C, the range of GT in the native starches was probably due to differences in the perfection of AP crystallinity which increased with barley growth temperature. All starches showed marked differences in their swelling curves which clearly related to ambient temperature. Swelling began at the same temperature as gelatinization (loss of crystalline order), At 80 °C, when there was no detectable order, swelling was determined primarily by AP content (45·3–97·6% in the 12 starches) but it was markedly inhibited by lipid (a temperature-dependent variable) probably through a mechanism which involved formation of AM-lipid inclusion complexes.