| Summary: | 碩士 === 國立中興大學 === 食品暨應用生物科技學系所 === 103 === Dragon fruit, which is rich in betacyanin (a natural pigment,) is a potential source of violet red natural colorant. In this study spray dried powder colorant was obtained to get more stable properties with different combinations including extraction solvents and carriers. Ethanol, water, 0.1% ascorbic acid were selected to be the solvent of the juice extraction. 60℃ 30 min and 80℃ 15 min were the extraction condition. There was no significant difference of ΔE among these 6 extraction products. Maltodextrin (MD), modified starch-starch sodium octenyl succinate (MS), and gum arabic (GA) were used as carriers for spray drying. Optimum conditions for spray drying were performed with juice content (40% solid content), and carrier (60%), at inlet drying air temperature around 160-170℃. The results show that the formula with MD has the highest moisture content, thus this powder had high water absorption and poor flowability. After 28-day storage, the formula with MD had caking property at 25 and 35℃; while the formula with MD-MS also had caking property at 35℃. After 60-day storage, there was no caking property on formula MD-MS and formula MS-GA at 25℃, and all three formulas were stable at 4℃. After 60-day storage, no matter caking or not, there had no significant difference among all samples on ΔE (ΔE<2). Applying formula MD-MS to produce a low pH product, the ΔE was stable during 14-day storage (ΔE<2). A sensory test was performed for a lactic beverage added with formula MD-MS. The data shows over 65% people liked this product and the addition of 1 ppm MD-MS dragon fruit juice powder was ranked as the first place. Therefore, dragon fruit juice powder has a great potential to be a new souce of natural colorant in food industries.
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