Effect of rainfalls on wheat quality in 2009 harvest season

Abstract

This paper analyses chemical, rheological and physical changes on grains, flour, dough and baked bread made of wheat variety Prima, caused by delayed harvest due to large quantity of precipitation. Possible grain defects were evident in lighter washed-out colour of grain coat, decreased test weight from 82.3 kg hl-1 to 78.9 kg hl-1 and decreased falling number (FN) from 232 sec to 145 sec. Changes in dough were observed in lower viscosity on amylograph, from optimal 740 AJ to 285 AJ as a consequence of possible presence of α-amylase and increased amylolitic activity in endosperm. Physical changes on the grains of unharvested wheat in fields did not influence rheological properties of dough nor the quality of baked product. Quality of bread made from wheat grain from delayed harvest was better than quality of bread made from wheat harvested are the beginning of harvest season.

Analizirane su hemijske, reološke i fizičke promene na zrnu, brašnu, testu i gotovom hlebu od sorte pšenice Prima, izazvane odlaganjem žetve zbog velikih količina padavina. Eventualna oštećenja zrna su registrovana svetlijom izbeljenom bojom omotača zrna, smanjenom hektolitarskom masom sa 82,3 na 78,9 kg hl-1 i smanjenim brojem padanja (FN) sa 232 na 145 sec. Promene na testu registrovane su smanjenjem viskoziteta na amilografu, sa optimalnog 740 na 285 AJ kao posledica eventualno prisutne α-amilaze i povećanja amilolitičke aktivnosti u endospermu. Fizičke promene na zrnu nepožnjevene pšenice u polju nisu uticale na reološka svojstva testa i kvalitet gotovog proizvoda. Kvalitet hleba napravljen od zrna pšenice iz produžene žetve bio je bolji nego od zrna požnjevenog na početku žetve.