• Journal of the Korean Dietetic Association
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• v.16 no.4
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• pp.341-352
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• 2010

The aim of this study was to use purple sweet potato powder to develop a recipe for a nutritional cookie with an optimal composition of ingredients and texture, in order to acquire strong preference responses by all age groups in sensory tests. Wheat flour was partially substituted with purple sweet potato powder to reduce the wheat flour content of the cookies. Measurements were made and analyzed according to the Response Surface Methodology technique, which showed 16 experimental points including 3 replicates for the purple sweet potato powder, sugar, and butter. The compositional and functional properties of the sample were measured, and the values obtained were applied to a mathematical model. A canonical form and perturbation plot showed the influence of each ingredient on the final product mixture. The results of sensory evaluations showed very significant values for flavor (P<0.0071), texture (P<0.0306), taste (P<0.0190), and overall quality (P<0.0142). Instrumental analysis showed significant values for hardness (P<0.0027), yellowness (P<0.0061) and spread ratio (P<0.0001). The optimal compositional ratios were determined to be 21.75 g for the purple sweet potato powder, 37.05 g for the sugar, and 60.59 g for the butter.

• Korean Journal of Food Science and Technology
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• v.44 no.1
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• pp.28-33
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• 2012

The effect of puffing conditions on the physical properties and sensory evaluations of a puffed snack (ppeongtuigi) made of purple sweet potato flour was investigated. The snacks consisted of coated artificial rice with purple sweet potato flour with water, tempered to 7%, 9% and 11% moisture. The coated material was puffed at 236, 241, or $246^{\circ}C$ for 4, 5, or 6 s. The $L^*$ value decreased as the heating time increased. The $a^*$ and $b^*$ values, specific volume, and hardness increased with increasing heating temperature and heating time. Puffed snacks produced under conditions of higher moisture (7%), higher heating temperature ($246^{\circ}C$), or longer heating time (5 s) showed high scores for appearance, color, taste, and overall acceptability in sensory evaluations.

• Journal of the Korean Society of Food Culture
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• v.32 no.4
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• pp.323-331
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• 2017

This study examined the quality characteristics of Jeung-pyeon made with wet non-glutinous rice flour and rice wine. The samples of Jeung-pyeon were prepared with different ratios of cooked purple sweet potato (0, 3, 6, 9, and 12%) to analyze the water content, sugar content, pH, chromaticity, texture characteristics, and sensory evaluation. No significant difference in water content, sugar content, and springiness was observed among the 5 samples. The pH and volume showed the highest level at 0%. The L-value and b-value decreased while the a-value increased. The hardness, chewiness, and gumminess were highest at 9% and lowest at 12%. The extent of violet chromaticity and pore size were optimal in 9%. In addition, 9%-added purple sweet potato showed the highest score of odor, taste, texture, and overall acceptability. In conclusion, the optimal addition for the highest acceptability of cooked purple sweet potato was 9%.

• Journal of the Korean Society of Food Science and Nutrition
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• v.39 no.10
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• pp.1476-1480
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• 2010

Physicochemical properties of flours prepared from sweet potatoes with different flesh color (white, yellow/orange and purple) were investigated. Sweet potatoes were soaked in solutions of antibrowning agents such as sodium metabisulfite and citric acid, and freeze or hot air-dried prior to grinding to produce sweet potato flours. Sweet potato flours with different flesh colors showed differences in chemical composition. Purplefleshed sweet potato flour had higher protein, ash, and dietary fiber contents that white and yellow/orangefleshed sweet potato flours. Average particle size of yellow/orange-fleshed sweet potato flour was higher than those of white/yellow or purple-fleshed sweet potato flour. Both water absorption index (WAI) and oil absorption capacity of flours prepared from sweet potatoes by hot-air drying were higher than those from sweet potatoes by freeze drying.

• Food Science and Preservation
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• v.19 no.6
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• pp.833-840
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• 2012

In this study, purple sweet potato muffins were made with the addition of 0, 25, 50, 75, and 100% rice flour, and their quality characteristics were determined. The weight and height increased with the increase in the amount of rice flour added. The moisture contents decreased significantly. As the amount of rice flour added increased, the pH and acidity decreased. The lightness and yellowness of the rice flour decreased significantly, but the redness increased with increasing purple sweet potato content. The textural properties, such as the cohesiveness, chewiness, and brittleness, were significantly lower in the groups with added rice flour. The DPPH radical scavenging activity was significantly higher in the purple sweet potato muffins to which 50 and 75% rice flour were added compared to those in the control. The results of the sensory evaluation showed that there was no significant difference in flavor among the samples. The chewiness was higher with 50, 75, and 100% rice flour than with 0 and 25% rice flour. The groups with 50 and 75% rice flour had significantly higher scores for overall acceptability compared to the control group.

• Journal of the East Asian Society of Dietary Life
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• v.20 no.2
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• pp.272-278
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• 2010

Various quality attributes were determined in muffins prepared using purple-colored sweet potato flour. Height of control muffins was 5.8 cm lease clarify. Height decreased with increasing quantity of sweet potato powder. Muffin volume was not appreciably affected. Moisture of control muffins was 21.84. The moisture value decreased with increasing quantity of sweet potato powder. Scanning electron microscopy examination revealed thick cell wall and rough stoma in muffins prepared with purple-colored sweet potato powder. The amount of gluten decreased as the quantity of purple-colored sweet potato powder increased. Brightness L values significantly changed as the amount of powder increased, indicative of a progressively darker product. Red index a values decreased as the quantity of purple-colored sweet potato powder increased. Yellow index b values decreased significantly in the control group as powder quantity increased. Hardness increased with increasing addition of powder, but no significant difference was evident between 6% and 9% amended samples. There were also no significant differences in springing in samples containing 3% and 6% powder but 9% powder produced a significant difference. Cohesiveness did not differ in unamended samples and samples amended with 3% and 9% powder, however a significant difference was evident in samples prepared with 6% powder. Gumminess and chewiness increased as the quantity of purple-colored sweet potato powder increased. Color did not differ appreciably in sample prepared with 3% and 9% Sample prepared with 3% additives showed the highest What? Color score? Something else? Please clarify with 6.4. There was no significant difference of the flavor in samples prepared with 3% and 6% powder, or in taste among samples prepared 3%, 6%, and 9% powder. No significant differences in texture were evident in any sample Overall acceptability was highest (7.2) in samples prepared with 3% of purple-colored sweet potato.

• Food Science and Biotechnology
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• v.18 no.6
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• pp.1487-1494
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• 2009

The effects of drying temperature (55, 60, and $65^{\circ}C$) and addition levels of maltodextrin (MD) (10, 20, and 30%) on the physicochemical properties and nutritional quality of purple sweet potato flour were investigated. MD-added flours had higher $L^*$ values, water soluble index, total phenolic, and anthocyanin contents than untreated flour. However, $a^*$, $b^*$ values, water absorption index, and swelling capacity were dependent on the drying temperature and MD concentration. On the other hand, untreated flour had a higher ascorbic acid content compared to the MD-treated flour. Ascorbic acid contents decreased, whereas anthocyanin content was not significantly different, with increasing drying temperatures. MD was positively correlated with phenolic content, anthocyanin, hue angle, and water soluble index. However, there was no correlation between quality parameters and glass transition temperature. The best quality product was obtained when samples were pretreated with MD before drying, regardless of drying temperature.

• Preventive Nutrition and Food Science
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• v.14 no.1
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• pp.60-65
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• 2009

Cookies were prepared by adding different levels (0, 5, 10, 15, and 20%) of purple sweet potato powder (PSPP) and their physicochemical and sensory characteristics were examined. With increase of the PSPP level, moisture content decreased and ash content increased (p<0.05). The spread factor of control cookies was higher than that of cookies containing PSPP. The incorporation of PSPP in cookies lowered the lightness and yellowness but increased redness (p<0.05). Texture measurement showed that the addition of PSPP did not affect the hardness of cookies. Results of acceptance test revealed that overall acceptability score was not significantly different between the control and the PSPP added cookies. Therefore, it is suggested that PSPP can be incorporated into cookies up to 20% without affecting the cookie quality. Total polyphenol content and antioxidant activity were assessed to examine the functionality of cookies. In addition, substitution of wheat flour with PSPP yielded cookies with higher polyphenol content and antioxidative activity (p<0.05). The peroxide value (POV) and acid value increased during storage at $60^{\circ}C$ for 80 days. The POV was significantly lower in cookies containing PSPP than the control cookies, suggesting that the addition of PSPP deterred the lipid oxidation (p<0.05).

• Korean journal of food and cookery science
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• v.13 no.4
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• pp.492-499
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• 1997

The effect of oxidants, gluten and gums on breadmaking quality of wheat-purple sweet potato(Ipomoea batatas) composite flour were studied. Alveograph tests of doughs showed that all additives increased the P, L and W values. Of these additives, L-Ascorbic acid, gluten, carboxy methyl cellulose have a significant effect on alveogram indexes. SEM showed that the dough added with additives changed some what in appearance when compared with the control. When oxidants was added, the doughs discontinuous gluten film were observed. No significant differences ,were evident in bread crumb color among the additives. And textural characteristics of bread crumb were influened by adding additives. Breads containing additives showed an increase in max weight, strength and hardness and a decrease in springness and cohesiveness. Average enthalpy values for all bread crumb after 7days increased with storage time. However, addition of additives decrease the rate of staling slightly more than that of the control. Addition of L-Ascorbic acid, L-Cystine, carboxy methyl cellulose and hydroxy propyl methyl cellulose increased the loaf volume significantly, and with except potassium bromate bread scores were acceptable.