Korrelation zwischen Lysin‐, Tryptophan‐ und Prolamingehalt während der Reifung des Maiskornes

Abstract

Correlation between lysine, tryptophan and prolamine contents during maturation of the maize kernel Changes in the contents of total nitrogen, prolamine, tryptophan and protein bound lysine, and the relative nutritive quality of proteins were studied during the maturation of three normal maize varieties, grown under the same topographical and agrotechnical conditions, in two successive crop years. Total nitrogen was determined according to Kjeldahl's method, prolamine by the turbidity test, lysine by Carpenter's method and tryptophan was assessed fluorometrically. A significant decrease (p = 0.01) in total nitrogen, tryptophan and bound lysine content in the dry grain matter was found in the late milk and early dough ripeness stages of the maize kernel. Parallel with the decrease in these components, the relative nutritive quality of proteins also decreased during maturation. Prolamine, which was present in the early milk stage in low quantities, increased significantly (p = 0.01) with kernel maturity, reaching the highest level in the early dough ripeness stage. During further kernel maturation no significant changes in the components studied were observed. The correlation coefficients between the contents of prolamine and total nitrogen, lysine and tryptophan, during the ripening of maize kernel were highly significant (p = 0.001): ‐0.891, ‐0.938, ‐0.856, respectively in the first crop year and –0.844, ‐0.833, ‐0.867, respectively in the second crop year.

Relationship Among the Phytic Acid and Protein Content During Maize Grain Maturation

“…The impact of environmental factors is manifested not only in phytic acid but also in other grain constitu-Phytic Acid and Protein Content in Grain ents. Grain maturation under conditions of increased moisture and lower temperatures also resulted in lower dry weight and lower total proteins and prolamine content in dry matter which was determined in our earlier studies (HORVATIC andBALINT 1991, 1993). These observation might indicate that the extent of accumulation of grain phytic acid is limited by the extent of dry matter accumulation, that is, biosynthesis of individual components of grain dry matter.…”

“…In our previous studies it was determined that dry matter and total nitrogen content in grain fresh weight of the investigated maize hybrids was significantly increasing (P = 0.01) during maturation (HORVATIC andBALINT 1991, 1993). At the same time, changes of the phytic acid content correlate positively and highly significantly (P = 0.001) with dry matter (which is primarily connected with accumulation of starch) in both vegetation years (Table 5).…”

Accumulation of Zinc and Molar Ratio of Phytic Acid and Zinc during Maize Grain Maturation

“…The purpose of our investigations was to determine the accumulation of zinc and total ash during maize grain maturation with relation to the deposition of dry matter, crude proteins and phytic acid which were determined in our previous articles (Horvatic and Balint 1991, 1996, and to calculate the molar ratio of phytic acid: zinc.…”

Changes of the Methionine Content During Maize Grain Maturation

“…The ammo acid composition of protems and protein fractions during maturation of maize grains was investigated by most authors whereat an mterest in the amino acids limiting biological values of these proteins was very often pointed out (BRESSANI and CONDE 1961, MuKPHY and DALBY 1971, WALL and BIETZ 1987, WALL et al 1988, HORVATIC and BALINT 1991, ORTEGA et al 1991. Maize proteins are a good source of methionine that is particularly abundant in the prolamine and glutelin component of the endosperm specific protein (HAN- SEL et al 1973, LANDRY and MOUREAUX 1980, Wu 1988).…”