Studies of the physico-chemical properties and polyphenoloxidase activity in seeds from hybrid sunflower (Helianthus annuus) varieties grown in India

Physico-chemical properties and polyphenol oxidase (PPO) activities of seven hybrid sunflower varieties commonly grown in Punjab state of India were studied. Seeds were studied for variations in physico-chemical properties, 100 kernel weight, density, bulk density, moisture, hull, oil, protein and ash content; expelled cake was studied for moisture, oil, crude fibre, ash and protein content and expelled-defatted cake for acid detergent fibre, lignin, moisture, ash and protein contents. PPO activity in all varieties, determined using pyrogallol as substrate at pH 6.5, varied between 0.212 and 0.294 Ab/min/mg protein. The PPO enzyme activity for MSFH-8 and Mega-363 was observed to be maximum at 55 and 60 degrees C, respectively. The enzyme showed a K-m value between 1.01 and 1.968 mM for pyrogallol and V-max value between 0.21 and 2.0 Ab/min. (C) 1999 Published by Elsevier Science Ltd. All rights reserved.