Process development of Gac powder by using different enzymes and drying techniques

New products from Gac, an indigenous fruit of Vietnam have been recently found in the worldwide markets as the aril part of the fruit has a high content of lycopene and β-carotene. These carotenoids are currently in special demand as they are natural antioxidants with potential to prevent and treat cancers. This study investigated some processing approaches for the production of powder from Gac arils and used currently developed analytical methods to measure the product qualities. The process development focused on the selection of a pre-treatment method before seed removal and a dehydration technique to minimise the degradation of the carotenoids after processing. The heat and enzymatic pre-treatments could be applied in an industrial-scale seed removal. However, using the same drying method the powder produced without enzymatic pre-treatment had a higher carotenoid content than the enzymatic-treated powder. Constant drying rates and critical moisture contents on a solid basis were measured for oven drying, air drying and vacuum drying. Spray drying and freeze drying were also attempted. Freeze-drying resulted in the Gac powder with the brightest colour and the highest level of carotenoids. The average loss of carotenoids of five Gac powder samples after pre-treatment and dehydration was 35%. These samples stored in vacuo below 25 °C could retain the red colour and 70% of carotenoids after 4 months. They were found to be acceptable in some trial food products.