Viscoelastic properties of sweet potato complementary porridges as influenced by endogenous amylases.

Sweet potato (Ipomoea batatas L.) roots contain amylolytic enzymes, which hydrolyze starch thus having the potential to affect the viscosity of sweet potato porridges provided the appropriate working conditions for the enzymes are attained. In this study, the effect of sweet potato variety, postharvest handling conditions, freshly harvested and room/ambient stored roots (3 weeks), and slurry solids content on the viscoelastic properties of complementary porridges prepared using amylase enzyme activation technique were investigated. Five temperatures (55°C, 65°C, 70°C, 75°C, and 80°C) were used to activate sweet potato amylases and the optimum temperature was found to be 75°C. Stored sweet potato roots had higher soluble solids (°Brix) content in the pastes compared to fresh roots. In all samples, activation of amylases at 75°C caused changes in the viscoelastic parameters: phase angle (tan δ) and complex viscosity (η*). Postharvest handling conditions and slurry solids content significantly affected the viscoelastic properties of the porridges with flours from stored roots yielding viscous (liquid-like) porridges and fresh roots producing elastic (solid-like) porridges. Increase in slurry solids content caused reduction in the phase angle values and increase in the viscosity of the sweet potato porridges. The viscosity of the porridges decreased with storage of sweet potato roots. These results provide a possibility for exploiting sweet potato endogenous amylases in the preparation of complementary porridges with both drinkable viscosities and appropriate energy and nutrient densities for children with varying energy needs.

Influence of development, postharvest handling, and storage conditions on the carbohydrate components of sweetpotato (Ipomea batatas Lam.) roots.

Changes in total starch and reducing sugar content in five sweetpotato varieties were investigated weekly during root development and following subjection of the roots to different postharvest handling and storage conditions. Freshly harvested (noncured) roots and cured roots (spread under the sun for 4 days at 29-31°C and 63-65% relative humidity [RH]) were separately stored at ambient conditions (23°C-26°C and 70-80% RH) and in a semiunderground pit (19-21°C and 90-95% RH). Changes in pasting properties of flour from sweetpotato roots during storage were analyzed at 14-day intervals. Significant varietal differences (p < .05) in total starch, sucrose, glucose, maltose, and fructose concentrations were registered. The total starch and sucrose content of the roots did not change significantly (p < .05) during root development (72.4 and 7.4%, respectively), whereas the average concentrations of glucose, maltose, and fructose decreased markedly (0.46-0.18%, 0.55-0.28%, and 0.43-0.21%), respectively. Storage led to decrease in total starch content (73-47.7%) and increase in sucrose and glucose concentrations (8.1-11.2% and 0.22-1.57%, respectively). Storage also resulted in reduction in sweetpotato flour pasting viscosities. Curing resulted in increased sucrose and glucose concentrations (9.1-11.2% and 0.45-0.85%, respectively) and marked reduction (p < .05) in total starch content (72.9-47.6%). This resulted in low pasting viscosities compared to flour from storage of uncured roots. These findings show that significant changes occur in the carbohydrate components of sweetpotato roots during storage compared to development and present an opportunity for diverse utilization of flours from sweetpotato roots in the food industry.

Ethnobotanical study of indigenous knowledge on medicinal and nutritious plants used to manage opportunistic infections associated with HIV/AIDS in western Uganda.

ETHNOPHARMACOLOGICAL RELEVANCE: Traditional medicine plays an important role in the daily lives of the people of Uganda to treat a wide range of health problems. Our study presents results of an ethnobotanical inventory conducted to identify and document medicinal and nutritional plants used in the management of opportunistic infections associated with human immunodeficiency virus / acquired immunodeficiency syndrome (HIV/AIDS), the plant parts used, preparation and administration methods of herbal remedies. MATERIALS AND METHODS: We performed semi-structured interviews with 79 respondents (women 78%, men 22%), who included specialists in medicinal plants (such as traditional birth attendants and herbalists) and non specialists with general knowledge of plant use. Respondents answered a semi-structured questionnaire regarding their knowledge of plants and general treatment practices including management of HIV/AIDS opportunistic infections. The reported plants were collected and identified. Data were analyzed using factor informant consensus and fidelity level to determine homogeneity of informants׳ knowledge on medicinal and nutritional plants suitable for different ailment categories and the most preferred plant species used to treat each ailment category in the study areas. RESULTS: The study revealed 148 plant species belonging to 54 families, most of which were herbs (50.7%). Leaves (61.6%) were the most frequently used parts in remedy preparations which were mainly administered orally (72%). The majority of plants (62%) were harvested from wild habitats. The most important species according to fidelity values are Hibiscus sabdariffa L. for anaemia, Mangifera indica L. for cough, Zehneria scabra (L. F.) Sond. for skin infections, Rhus natalensis Bernh.ex.Krauss for diarrhoea and Tarenna pavettoides (Harv.) Sim for appetite boosting. The factor informant consensus highlighted the agreement in the use of plants and showed that the respiratory infections category had the greatest agreement (0.60). Family Asteraceae accounted for 15% of the total species recorded. Sixty plant species (40%) of the plants provide nutritional support. CONCLUSION: The study revealed that folk medicine is still widely practised. Fidelity level values indicate that these plants are the most preferred species for particular ailments. The high consensus value (0.6) indicated that there was high agreement in the use of plants for respiratory ailments among others. These preferred plant species could be prioritized for conservation and subjected to chemical screening to ascertain their pharmacological activities.

Ethnobotanical study of nutri-medicinal plants used for the management of HIV/AIDS opportunistic ailments among the local communities of western Uganda.

ETHNOPHARMACOLOGICAL RELEVANCE: Herbal remedies are a source of therapeutics for nearly 80% of the population in Uganda. Poor health facilities and limited access to antiretroviral drugs have perpetuated and increased the use of traditional medicine especially in rural areas for the treatment of opportunistic ailments of HIV/AIDS. To document the traditional uses of nutri-medicinal plants in the management of immunocompromised ailments associated with HIV/AIDS. To document the parts and growth forms of plants used, methods of preparation and administration of the herbal remedies. MATERIALS AND METHODS: The study was conducted in Mbarara and Isingiro districts of western Uganda between December 2010 and May 2011. Ethnobotanical information was collected from 64 respondents who were sampled based on recommendations of local elders and administrators. Ethnobotanical data on the use of nutri-medicinal plants for traditional treatment of HIV/AIDS opportunistic ailments were collected by employing semi-structured interviews with selected respondents, house hold visits and field observations as described by (Martin, 1995a). The respondents were mainly traditional medical practitioners who treat patients who are already receiving antiretroviral drugs. Fidelity levels of plant species and informant consensus factor were determined to show the percentage of informants claiming the use of certain plant species for the same major purpose and to analyse people's knowledge of plant use. RESULTS: The study revealed 81 plant species most of which were herbs (49%). Leaves (71%) were the most frequently used parts in remedy preparations which were mainly administered orally (85%). The majority of plants (54%) were harvested from wild populations. Hibiscus sabdariffa L., Plumeria obtusa L., and Abutilon guineense (Shumach.) Baker. F and Exell were the nutri-medicinal plants that scored the highest Fidelity level values. The informant's consensus about usages of plants ranged from 0.75 to 0.80. Plants that are presumed to be effective in treating a certain disease have higher informant consensus factor (ICF) values. Family Asteraceae accounted for 18% of the total species recorded. Thirteen species (16%) of the plants are edible and provide nutritional support. CONCLUSION: The study recorded plant species with potential to treat ailments associated with immunocompromised people living with HIV/AIDS in western Uganda. Such studies can help stimulate confidence in traditional medicine and enhance appreciation of herbal medicine among the people and to appreciate the value of the plant resources and therefore enhance conservation efforts of the plant species. The high consensus means the majority of informants agree on the use of plant species and this reflects the intercultural relevance and the agreement in the use of the nutri-medicinal plants to the people. We recommend the documented plants for further Ethnopharmacological studies.

Microstructure and in vitro beta carotene bioaccessibility of heat processed orange fleshed sweet potato.

Orange fleshed sweet potato (OFSP) has been identified as a good source of beta-carotene but the beta-carotene bioaccessibility is affected by processing. In this study, the effect of traditional heat processing methods on the microstructure and in vitro bioaccessibility of beta-carotene from OFSP were investigated. Bioaccessibility was determined using simulated in vitro digestion model followed by membrane filtration to separate the micellar fraction containing bioaccessible beta-carotene. Processing led to decrease in the amount of all-trans-beta-carotene and increase in 13-cis-beta-carotene. Processed OFSP had significantly higher (P < 0.05) bioaccessible beta-carotene compared to the raw forms. Bioaccessibility varied with processing treatments in the order; raw < baked < steamed/boiled < deep fried. Light microscopy showed that the microstructure of OFSP was disrupted by the processing methods employed. The cell walls of OFSP were sloughed by the traditional heat processing methods applied. The findings show that heat processing improves bioaccessibility of beta-carotene in OFSP and this was probably due to disruption of the tissue microstructure.