Purple sweet potatoes contain anthocyanins which could function as a natural food colorant, and an antioxidant. One of the problems in handling the fresh roots is their susceptibility during storage, and to extend their uses, fresh purple sweet potato could be processed into flour. However, during flouring process, the properties of the purple sweet potato may undergo some changes such as partial gelatinization of the starch and discolorization. Therefore, the purpose of this study was to investigate the effect of pre-heating treatment during flouring process on degree of gelatinization, the anthocyanin content, the antioxidant activity and the total phenolic content of heat treated purple sweet potato flour. Other objectives were to observed the changes in the starch properties such as rheological properties, granular appearance of the heat treated- purple sweet potato flour. Pre-heating treatment of purple sweet potato flour was prepared by heating grated purple sweet potato in a single rotary drum cooker at 90°C for 15, 30, 45, 60 and 75 min, followed by drying in a cabinet dryer at 60°C for 8 h. The results showed the longer pre-heating time at 90°C had caused increase in the degree of gelatinization, increase in total phenolic and anthocyanin retention. In addition, differences in gelatinization temperature, maximum viscosity, paste stability and retrogradation, and differences in scanning electron microscope (SEM) of granular appearance were also observed. The overall results indicated that pre-heating treatment can be used for modifying the physical, chemical and rheological properties to suit various applications and preserving functional properties of purple sweet potato flour.

The use of locally grown crops such as sweet potato as raw material for composite flour is considered advantageous as it reduces the importation of wheat flour. However the use of native sweetpotato flour has drawback properties when applied in the food. This study was aimed to modify sweet potato flour through six methods of lactic fermentation (spontaneous, pickle brine, Lb plantarum, Lc mesentereoides, a mixed of Lb plantarum and Lc mesentereoides, and mixed of Lb plantarum, Lc mesentereoides and yeast) to increase its properties in composite flour. Composite flours were obtained after fermentation of sweet potato slices for 48h in the proportion of 50% sweet potatoes flour and 50% wheat flour. pH, moisture content, swelling power, solubility, and pasting properties were determined for the fermented and unfermented composite flours. The results indicated that the composite fermented flours had better properties than those of non fermented flour. Fermentation increased swelling power, moisture content, meanwhile, solubility, and pH, deacresed. Amylose leaching, however, was not significantly affected by the fermentation process.

Starch can be added to yogurt to improve its body and texture, specially to increase viscosity and reduce syneresis. Starch utilization in a product can be done in the form of flour containing the main component of the starch. This study aims to determine the concentration of fermented sweet potato flour (FSPF) to produce the best quality characteristics of Ambon banana yogurt, significantly reducing syneresis and retain sensory yogurt. In this research, three levels of fermented sweet potato flour (0, 1, and 2 %) with three replicates were considered. The results showed that fermented sweet potato flour affects the quality characteristics of Ambon banana yogurt, and FSPF supplementation is proven to reduce syneresis. The best characteristics of yogurt are found in fermented sweet potato flour concentration of 2%, which produces a viscosity of 3400 cP, protein content of 3.72%, and fat content of 4.45%; syneresis 3.97%; total dissolved solids was 18.77%, and the sensory score was around four or like.

Efforts to increase the potential utilization of cassava bagasse (tapioca industrial by-product) as food can be done by improving its appearance (colour and odour), increasing protein content, and decreasing HCN levels. The aim of this research was to apply the abrasion peeling method and fermentation process using Saccharomyces cerevisiae in powder form to improve the characteristics of the cassava bagasse flour. The study was prepared in a Completely Randomized Block Design with 2 factors. The first factor was peeling method with two levels: washing method and abrasion method; the second factor was fermentation time with four levels, i.e. 1 day, 2 days, 3 days, and 4 days. The results research showed that the treatment of abrasion method and 4-days fermentation was the best treatment which will produce the cassava bagasse flour with protein content as 6.98%, cyanide content as 8.87%, whiteness degree as 52,70%, odour score as 5.95, starch content as 46.69%, dietary fiber as 23.13% and fat content as 0.95%. Compared to the cassava bagasse flour produced by the small-scale tapioca industry, the cassava bagasse flour of this research had a better white degree (52.70 versus 31.50), higher protein content (6.98% versus 0.92%), lower cyanide content (4.67 ppm versus 30.52 ppm), and a better odor score (5.95 versus 4.50). Improved appearance, increased protein content, and decreased cyanide content through improved peeling methods and the application of fermentation processes will increase the potential use of cassava bagasse as food.