Properties of flour from blanched tubers of two water yam (Dioscorea alata) cultivars were compared with those from the non blanched ones. The results showed that the proximate composition of flours from the yellow cultivar was different from that of the purple cultivar. Steam blanching (97±2°C, 7 min) on the purple cultivar resulted in more significant reduction on yield and the Lightness (L) value. However, it had significant effect on some components of the flours such as protein, ash, amylose and fiber. Results of proximate composition showed crude fat yellow and purple water yam ranging from 0.4 to 0.55%, crude protein 5-8%, dietary fiber 16-26% and starch 41-76%. Starch granule size between 20-40 µm. Blanched yellow water yam flour has the highest water and oil absorption which is 2.02 and 1.18 g/g. Dioscorine and water soluble polysaccharides, bioactive components from Dioscorea, of purple water yam flour are larger than the yellow flour. Purple water yam flour is better to be proceed as a functional food because it has a high peak viscosity, more stable to heat and has greater content of bioactive compounds. Steam blanching decrease the yield of dioscorine and water soluble polysaccharide.

Palm fatty acid distillate (PFAD) is a b y-product of palm oil refining that contains valuab le b ioactive compounds such as phytosterols, tocopherol, tocotrienols, and squalene which acummulates in unsaponifiab le fraction (USF). In emulsion form, USF will b e convenien t and easy to use as food supplements or fortificants. Microemulsion is a type of emulsion that has stab le droplet sizes of less than 10 m. Hence, the b est emulsifier for USF microemulsion is important to b e determined. The USF microemulsion was prepared b y homogenizing the sample mixtures at 12.000 rpm for 20 min at USF concentration of 10% (w/v) with lecithin and tween 80 as the emulsifiers at concentratiosn of 0.5 , 1.0, and 1.5% (w/v). The microemulsions were analyzed for their viscosity, stab ility, and particle size distrib utions, as well as microstructures. The results showed that characteristics of microemulsion were affected b y emulsifier types and concentrations. Tween 80 produced b etter microemulsion than lecithin as indicated by more stab le emulsions, smaller droplet sizes, and narrower ranges of droplet size distrib utions. Increasing lectihin concentrations resulted in a narrower droplet size distrib ution b ut the average droplet size was not always smaller. Conversely, increasing tween 80 concentrations increased the average droplet sizes and ranges of particle size distrib utions. The most suitab le emulsifier for USF microemulsion was tween 80 at concentration of 0.5%. This microemulsion contained b ioactive compounds derived from USF, namely vitamin E (mainly tocotrienols), phytosterols, and squalene.

The growth and pigment production of Monascus purpureus during 14 days solid state fermentation on different cereal substrates i.e. rice, corn, whole sorghum grain (WSG), dehulled sorghum grain (DSG) and sorghum bran (SB); and pigment composition of the fermented-products have been evaluated. Fungal biomass was used as a basis of its growth. Pigment content was measured by using spectrophotometer and thin-layer chromatography, and its composition was analyzed by using liquid chromatography coupled with tandem mass spectrometry. M. purpureus grew faster on rice substrate than did on other substrates. Production of pigments was observed at the end of logarithmic phase on all substrates tested. Similar pigment compounds were found on all substrates and the highest production of pigments was on rice, followed by DSG 4WSG4Corn 4SB. Twelve pigments, six of which were well-known, were detected on the Monascus-fermented products at different levels. Among those, Monapilol B, found in Monascus-fermented dioscorea, was found. On all cases, the red pigment Rubropunctamine was the major one (57-87%), except on SB substrate which produced Yellow II as the major one. Interestingly, fermented-DSG contained a large amount of Rubropunctatin compared to other fermented products. Among the non-rice substrates, DSG is the most potential substrate, on which the fungus exhibited the highest growth and pigment production. These data suggest that the fermented products are good candidates for development of natural food colorant, food supplement, functional food and or medicine with antiinflammation, anticancer and antimicrobial activities.

This research studied the optimization conditions for separation and purification of omega-3 (-3) fatty acids from the by-product of tuna canning processing by urea crystallization. Crystallization reaction conditions of urea inclusion (urea to fatty acid ratio (X 1 ) and crystallization time (X 2 )) were optimized using the Response Surface Methodology (RSM) and a model was developed. Optimization results showed a quadratic polynomial regression equation of Y = 24.44X 1 + 5.65X 2 -8.71X 1 2 -0.19X 2 2 + 1.171X 1 X 2 -12.95. The maximum response was obtained at an urea to fatty acid ratio of 2.99:1 and a crystallization time of 23.64 h and predicted response of 90.44%. Analysis of variance showed that the urea to fatty acid ratio and crystallization time affected the response. Verification under optimal conditions showed that the purity of -3 fatty acids was 89.64% and the enrichment was 2.85 fold. Verification result revealed that the predicted value from this model was reasonably close to the experimentally observed value. The urea crystallization process changed oil quality parameters including oxidation level (peroxide, anisidin, and totox values), Fe, Cu and P concentrations and moisture content and this were mostly due to the saponification process before urea crystallization.

Water yam (Dioscorea alata L.) is suitable for resistant starch high flour because of its high amylose content. The purple, yellow, and white water yams were treated by autoclaving and cooling with one, two, and three cycles to obtain resistant starch. Water yam tubers were cooked in an autoclave for 15 min, and then cooled prior to drying. Autoclaving-cooling of water yams decreased protein, fat, dietary fiber, water soluble polysaccharide, dioscorin, and diosgenin but increased amylose and sugar. The treatments significantly raised resistant starch and reduced in vitro starch digestibility that depended on water yam types, and affected starch granule morphology.