ISHS Acta Horticulturae 744: I International Symposium on Human Health Effects of Fruits and Vegetables
EFFECT OF CULTIVAR AND PROCESSING ON PHENOLICS AND ANTIOXIDANT ACTIVITY OF APPLE PRODUCTS |
| Authors: | J. Markowski, W. Plocharski, M. Mieszczakowska |
| Keywords: | polyphenols, ABTS, juice, cloudy juice, apple sauce |
| Abstract:
Phenolics composition and antioxidant activity of selected apples (‘Champion’, ‘Jonagold’, ‘Idared’ and ‘Topaz’) and their processed products like clear and cloudy juices and apple sauce were evaluated. Cloudy juices were produced without mash enzymation with ascorbic acid addition in quantity of 200 mg/kg of apples. Clear apple juices were produced with Panzym MK at 50oC (hot processing) or Rohapect MA Plus at 20oC (cold processing). For the determination of phenolic compounds HPLC column Phenomenex Fusion-RP was used. The dominant phenolic groups in fruits were flavonols, followed by phenolic acids. Sum of phenolics content in apples and apple sauces was on similar level and amounted on average to 821 mg/kg for fruits and 800 mg/kg for sauces, whereas in cloudy juices it was on average 430 mg/kg. Clear juices contained lower amount of phenolics, for juices hot processed 315 mg/kg and for juices cold processed only 149 mg/kg. The antioxidant activity of apples and processed products was determined by the spectrophotometric method using ABTS. Results were expressed as mg of Trolox equivalents. Measurements showed that the highest activity had fruits (1.70 mg/g) followed by apple sauce (1.47 mg/g), cloudy juices (0.85 mg/g), clear juices hot processed (0.76 mg/g) and juices cold processed (0.41 mg/g). Juices from cultivars ‘Topaz’ and ‘Champion’ had higher phenolics and antioxidant activity than juices from cultivars ‘Idared’ and ‘Jonagold’. Antioxidant activity measured by ABTS method showed significant correlation with the sum of determined phenolics content (for all investigated products R2=0.955; clear juices R2=0.986). | |
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