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 seve n hybrid sunflower varieties commonly grown in Punjab state of India were s tudied. Seeds were studied for variations in physico-chemical properties, 1 00 kernel weight, density, bulk density, moisture, hull, oil, protein and a sh content; expelled cake was studied for moisture, oil, crude fibre, ash a nd protein content and expelled-defatted cake for acid detergent fibre, lig nin, moisture, ash and protein contents. PPO activity in all varieties, det ermined 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 sh owed a K-m value between 1.01 and 1.968 mM for pyrogallol and V-max value b etween 0.21 and 2.0 Ab/min. (C) 1999 Published by Elsevier Science Ltd. All rights reserved.