Abstract
Anthocyanins are natural antioxidants which are of current interest to the food industry for their potential health benefits and availability. Blackcurrants are high in anthocyanins and are the subject of this study which investigates the use of ultrasound during blackcurrant juice extraction. This investigation was performed to mimic the industrial processes of blackcurrant juice extraction on a lab scale and discover if an ultrasonic process has potential to improve juice extraction in terms of pH, acidity, bluing and browning indices, brix , anthocyanin content, juice and solids yeild. The effects of ultrasound when used before, during, and after enzyme treatment have been investigated, as well as the effects of the duration and frequency of sonication.When sonicating for 15 minutes before enzyme treatment, the most effective frequency in terms of total anthocyanin yield is 40 kHz, this increased total
anthocyanins by 32.34%. When sonicating for 15 minutes simultaneously with enzyme treatment, the most effective frequency was 850 kHz, which increased anthocyanin content by 26.33%. The greatest increase in total anthocyanin content
was found in experiments using a 20 kHz probe for 30 minutes after enzyme treatment, this gave an average increase of 42.55% when compared to a control process. 15 minutes of sonication gave similar results, increasing total anthocyanin content by 42.37%, this was found to be the most effective frequency when used after enzyme treatment.
| Date of Award | 2010 |
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| Original language | English |
| Awarding Institution |
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| Supervisor | Larysa Paniwnyk (Supervisor), Timothy Mason (Supervisor), Andrew Cobley (Supervisor) & Yvonne Elliott (Supervisor) |