Red Sweet Potato Research Articles

Characteristics of Fermentation Drink made from Juice of Winged Bean Sprouts (Psophocarpus tetragonolobus) and Red Sweet Potato (Ipomoea batatas)

Fermented milk is a product that was produced from fermentation of fresh milk using lactic acid bacteria, such as Lactobacillus bulgaricus and Streptococcus thermophilus. A variety of plant materials can also be used as raw material in making of fermentation drinks, such as nuts and tubers. The purpose of this study was to investigate the characteristics of fermentation drink made from juice of winged bean sprout and red sweet potatoes. The treatment in this study is the level of mixing between juice of winged bean sprout with red sweet potatoes , consist of ;A (30:70), B (40:60), C (50:50), D (60:40) and E (70:30). Completely randomized design had been used with 5 treatments and 3 replications. The data colected was pH, viscosity, protein content, fat content, total solids, total acid, ash content, calcium content, total lactic acid bacteria, total plate count and sensory evaluation. Data processing is performed using statistical 8, followed by Tuckey test HSD All-Pair wise Comparisons Test at level of 5%. Mixing of winged bean sprouts with red sweet potato can increase the value of pH, viscosity, protein content, fat content, total solids, total acid, ash content, calcium content, and total lactic acid bacteria. The best product was the product of B (40% winged bean sprout and 60% red sweet potatoes) already meets SNI 7552:2009, contain : 2.36% protein content, fat content of 1.24%, 18.77% total solids, pH was 4, 2, 0.54% total acid, 0.23% ash content, 0.173% calcium content, viscosity was 3.56 DPA, total lactic acid bacteria (CFU / ml) was 1.9 x1010 , total plate count was 2.1 x1010 (CFU / ml).

PREPARATION AND PROPERTIES OF PROBIOTIC FROZEN YOGHURT MADE WITH SWEET POTATO AND PUMPKIN

Low-fat frozen yoghurt was made by using commercial probiotic (Lactobacillus acidophilus, Streptococcus thermophilus & bifidobacteria) and traditional (Lactoba-cillus delbrueckii ssp. bulgaricus & Streptococcus thermophilus) starters; as well as; roasted red sweet potato and pumpkin for enhancing nutritional and functional val-ues of this products. The preparing mixes and resulting frozen yoghurt stored at -20oC for 8 weeks were evaluated for physicochemical, bacteriological and organo-leptic properties. The results revealed that, there was significant differences (p<0.05) in all properties studied among the mixes and resulting frozen yoghurt. Frozen yoghurt mixes made with traditional yoghurt starter and sweet potato had higher specific gravity, weight per gallon, freezing point and apparent viscosity, but lower in pH values than the mixes made with probiotic starter. Also, resulting frozen yoghurt prepared with traditional starter and sweet potato had higher specific gravi-ty, weight per gallon, freezing time, melting resistance and acetaldehyde content, but lower in overrun % and diacetyl content than that made with probiotic starter. Counts of Lb. delbrueckii ssp. bulgaricus, Str. thermophilus (traditional starter) and Lb. acidophilus were the most numerous in pumpkin frozen yoghurt, followed by sweet potato frozen yoghurt. On the other hand, sweet potato frozen yoghurt had higher Str. thermophilus & bifidobacteria (probiotic starter) counts, than the other treatments. However, frozen storage for 8 wk was slightly effected on the viable bacterial counts determined of different frozen yoghurt treatments, and bifidobacte-ria counts were still higher along the storage period than the recommended mini-mum levels. Also, frozen yoghurt manufactured with probiotic starter; especially with sweet potato; had the highest total organoleptic scores. Therefore, low-fat fro-zen yoghurt with improved nutritional and functional values, and also good organo-leptic properties could be made by traditional yoghurt and probiotic starters; as well as roasted red sweet potato and pumpkin.

Comparative Studies Of The Physicochemical Properties Of Two Local Varieties Of Sweet Potato Flours

A study was conducted to determine the physicochemical characteristics and processing properties of white and red sweet potato varieties. Blanching treatments with 0.5% hot sodium metabisulphite solution was the most effective in both varieties. Chemical analysis of the fresh red and white sweet potato varieties showed significant differences (p Key words: Comparative studies, physicochemical properties, and varieties, sweet potato flours. Nigerian Food Journal Vol.22 2004: 141-146

Stability of anthocyanin-based aqueous extracts of Andean purple corn and red-fleshed sweet potato compared to synthetic and natural colorants

Anthocyanin-based aqueous Andean red sweet potato and purple corn extracts were evaluated under different pH, temperature, and light conditions, and compared to commercial colorants (purple carrot, red grape, red 40, and red 3). Red sweet potato and purple carrot colorants, rich in acylated anthocyanins, showed higher stability than purple corn and red grape colorants, rich in non-acylated anthocyanins. After storage at 20 °C for 138 days, the order of stability in the pH range 0.9–4 was: red sweet potato ⩾ purple carrot > purple corn > red grape. After this storage time, red sweet potato pH 4 extracts maintained a red-violet hue. Half-lives for pH 3 extracts at 98 °C were 4.6, 4.6, 2.4, and 2.0 h for red sweet potato, purple carrot, red grape, and purple corn, respectively. The hues for purple corn pH 3 extracts were similar to those of red 40. Parameters measured included degradation index, polymeric colour, colour retention and spectral data.

Serum retinol concentrations in children are affected by food sources of ²-carotene, fat intake, and anthelmintic drug treatment

The provision of vitamin A in food sources of beta-carotene is an alternative to the distribution of high-dose capsules. To examine factors that may influence the success of food-based programs, a study was carried out in Sumatra, Indonesia, of the effect of food sources of beta-carotene, extra dietary fat, and Ascaris lumbricoides infection on serum retinol concentrations in children. Meals and snacks with various amounts of beta-carotene and fat were fed at midday to children 3-6 y of age for 3 wk. Some groups of children were dewormed with the anthelmintic levamisole before the feeding period, whereas others remained infected. Results showed that the incorporation of beta-carotene sources (mainly in the form of red sweet potatoes) into the meal significantly increased serum retinol concentrations. The greatest rise in serum retinol occurred when meals contained added beta-carotene sources and added fat and the children were dewormed. Adding more fat to the meal and deworming the children caused a rise in serum retinol similar to that seen when feeding additional beta-carotene sources. Moreover, the effects of fat and deworming together were additive to the effects of additional beta-carotene sources. When the meal contained additional beta-carotene sources, added fat caused a further improvement in serum retinol concentrations but only if A. lumbricoides infection was low. These studies indicated that food-based interventions in vitamin A-deficient areas might be successful and that other interventions such as increasing dietary fat concentrations and anthelmintic treatment should be considered along with increasing consumption of beta-carotene-rich food.

Anthocyanin Pigments of Sweet Potatoes–Ipomoea batatas

ABSTRACTThe anthocyanin pigments of red sweet potato roots (Impomoea batatas) were isolated, purified and identified by HPLC and conventional paper chromatographic, spectral and chemical methods. Two major pigments and two minor pigments were present in fresh tissue slices extracted with boiling 1% HAc methanol. Tissues extracted cold yielded 11 or more pigments probably from degradation of the two major pigments. One major pigment was identified as peonidin‐3‐diglucoside‐5‐glucoside with three molecules of ferulic acid and one molecule of caffeic acid. The other major pigment was peonidin‐3‐diglucoside‐5‐glucoside with two molecules of ferulic acid and one caffeic acid.

Stability of Anthocyanins from Sweet Potatoes in a Model Beverage

ABSTRACTModel beverages containing a citrate‐phosphate buffer at pH 2.8, 13% sucrose, and a colorant were stored at room temperature for 1 yr in the dark. The colorants consisted of pigment extracts from red sweet potatoes, the same extract with the acyl groups removed, cyanidin‐3‐glucoside from blackberries, and a commercial sample of enocyanin from grapes. The sweet potato pigments were the most stable, closely followed by those from blackberries. The deacylated samples and those containing enocyanin were much less stable, as judged by color measurements and pigment analyses.

‘Scarlet’ Sweet Potato1

Abstract ‘Scarlet’ sweet potato [Ipomoea batatas (L.) Lam.], designated NCM-283 during testing, was released by the North Carolina Agricultural Research Service. ‘Scarlet’ is a dark-skinned sweet potato with orange flesh intended for growers and consumers desiring deep red to purple skin color. The major advantage of this cultivar over other red sweet potatoes is the greater intensity and stability of the dark skin color. The skin color is distinctly darker at harvest and more stable in storage than those of ‘Copper Skin Jewel’, the most widely grown red skin cultivar in North Carolina, and ‘Red Jewel’, a cultivar popular in other areas of the southeastern United States but not grown in North Carolina. Many characteristics of ‘Scarlet’ are similar to ‘Jewel’ (2); foliage growth habit, disease resistance, and insect resistance are all similar. However, ‘Scarlet’ has a distinct root shape and it scored significantly higher in baking trials.

Trypsin-induced ATPase Activity in Potato Mitochondria

Potato mitochondria (Solanum tuberosum var. Russet Burbank), which readily phosphorylate ADP in oxidative phosphorylation, show low levels of ATPase activity which is stimulated neither by Mg(2+), 2,4-dinitrophenol, incubation with respiratory substrates, nor disruption by sonication or treatment with Triton X-100, individually or in concert. Treatment of disrupted potato mitochondria with trypsin stimulates Mg(2+)-dependent, oligomycin-sensitive ATPase activity 10- to 15-fold, suggesting the presence of an ATPase inhibitor protein. Trypsin-induced ATPase activity was unaffected by uncoupler. Oligomycin-sensitive ATPase activity decreases as exposure to trypsin is increased. Incubation at alkaline pH or heating at 60 C for 2 minutes also activates ATPase of sonicated potato mitochondria. Disruption of cauliflower (Brassica oleracea), red sweet potato (Ipomoea batatas), and carrot (Daucus carota) mitochondria increases ATPase activity, which is further enhanced by treatment with trypsin. The significance of the tight association of the inhibitor protein and ATPase in potato mitochondria is not clear.