36E-97 |
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J. YANG, College of Natural and Applied Siences, Univ. of Guam, UOG Station, Mangilao, 96923, Guam and R. L. Gadi, College of Natural and Applied Sciences, Univ. of Guam, UOG Station, Mangilao, 96923, Guam. Anthocyanins are natural pigments. Aclylated anthocyanins are more stable than non-aclylated anthocyanins to pH, heat and light. Purple flesh sweet potatoes (Ipomoea batatas) possess high content of aclylated anthocyanins. Our objective was to determine the total anthocyanin content and color values of the Western Pacific purple sweet potato powders and evaluate potential application of powders. Fresh or steamed purple sweet potatoes (cultivar “Terlaje”) were dehydrated with freeze dry, hot air, and vacuum oven. Powders were extracted with 1% HCL acidic water. The total anthocyanin content was measured with the UV spectrophotometer based on monomeric anthocynin pn 3-caf.sop-5-glc. Polymeric anthocaynins were assayed with bisulfite treated extracts. The color values (L*, a*, b*) of powders and purple sweet potato noodles were evaluated with Chroma meter. The noodle color preferences were evaluated with consumer acceptance test. The anthocyanin contents of powders from fresh and steamed sweet potatoes are 2.16 and 2.17 mg/gram by freeze dry, 1.03 and 1.48 mg/gram by hot air dry, and 1.19 and 1.18 mg/gram by vacuum oven dry, respectively. The polymeric anthocyanin contents of powders from fresh and steamed sweet potatoes are 9.4 and 36.8% by freeze dry, 19.5 and 21.1% by hot air dry, and 30.8 and 40.5% by vacuum oven dry, respectively. Freeze dried powders exhibited color with L* 63.2, a* 17.5 and b* -5.1. Hot air dried powders exhibited color with L* 62.5, a* 13.4 and b* 3.6. Vacuum oven dried powders exhibited color with L* 68.5, a*9.6 and b*14.8. Noodles made with 40% steamed hot air dried powders presented a pleasant blue color with L* 42.0, a* 13.8, and b*-3.46. The cooked noodles were well accepted by consumers. Dehydration and steaming of purple sweet potatoes affect anthocyanin content in powders. The purple sweet potato powders from the Western Pacific can be potentially applied in foods.
Session 36E, Fruit & Vegetable Products: General
2005 IFT Annual Meeting, July 15-20 - New Orleans, Louisiana |