Effects of substituting skimmed milk powder with modified starch in yoghurt production

Rheological properties of yoghurt are known to be influenced by several factors during processing including the milk composition, additives, the type of culture (ropy or non ropy), heat treatment and mechanical processes it undergoes after fermentation. The objective of this study was to determine the most appropriate levels of modified starch that could be added in the yoghurt without noticeably altering the keeping quality and consumer acceptability of the yoghurt. A stirred type of yoghurt was developed using modified corn starch as a stabiliser to variably replace skimmed milk powder (partially or in totally) while maintaining the samequality and consumer acceptability on the yoghurt product. Different formulations were made and their quality characteristics studied using the 3% skimmed milk powder sample as the control. The results showed that the modified corn starch addition did not affect the gelation process, texture, fermentation time and the desired pH end point. Two sample formulations were identified as the most comparable to the control in terms of viscosity, taste, mouth]feel and general acceptability. These were the 0.5% modified corn starch alone and 0.5% modified corn starch with 1% skimmed milk powder. These reduced the cost of production per litre by 22% and 13% respectively. The samples were stable for three consecutive weeks in all the desirable yoghurt quality parameters tested includingconsumer acceptability. In conclusion, the application of modified starch at the level of 0.4% was found to have the most significant reduction in cost of production while having the least effect on the keeping quality and consumer acceptability of the yoghurt. Key words: Yoghurt, starch, quality, acceptability, cos

Effects of a transverse magnetic field on turbulent-natural convection fluid flow in a cubical enclosure

No Abstract

Defining the vaccination window for respiratory syncytial virus (RSV) using age-seroprevalence data for children in Kilifi, Kenya

Background Respiratory syncytial virus (RSV) is an important cause of lower respiratory tract disease in early life and a target for vaccine prevention. Data on the age-prevalence of RSV specific antibodies will inform on optimizing vaccine delivery. Methods Archived plasma samples were randomly selected within age strata from 960 children less than 145 months of age admitted to Kilifi County Hospital pediatric wards between 2007 and 2010. Samples were tested for antibodies to RSV using crude virus IgG ELISA. Seroprevalence (and 95% confidence intervals) was estimated as the proportion of children with specific antibodies above a defined cut-off level. Nested catalytic models were used to explore different assumptions on antibody dynamics and estimate the rates of decay of RSV specific maternal antibody and acquisition of infection with age, and the average age of infection. Results RSV specific antibody prevalence was 100% at age 0-<1month, declining rapidly over the first 6 months of life, followed by an increase in the second half of the first year of life and beyond. Seroprevalence was lowest throughout the age range 5–11 months; all children were seropositive beyond 3 years of age. The best fit model to the data yielded estimates for the rate of infection of 0.78/person/year (95% CI 0.65–0.97) and 1.69/person/year (95% CI 1.27–2.04) for ages 0-<1 year and 1-<12 years, respectively. The rate of loss of maternal antibodies was estimated as 2.54/year (95% CI 2.30–2.90), i.e. mean duration 4.7 months. The mean age at primary infection was estimated at 15 months (95% CI 13–18). Conclusions The rate of decay of maternal antibody prevalence and subsequent age-acquisition of infection are rapid, and the average age at primary infection early. The vaccination window is narrow, and suggests optimal targeting of vaccine to infants 5 months and above to achieve high seroconversion

Novel flow cytometry technique for detection of Plasmodium falciparum specific B-cells in humans: increased levels of specific B-cells in ongoing infection

Malaria caused by Plasmodium falciparum is still a major health threat in endemic areas especially for children below 5 years of age. While it is recognized that antibody immunity plays an important role in controlling the disease, knowledge of the mechanisms of sustenance and natural boosting of immunity is very limited. Before, it has not been possible to investigate malaria specific B-cells directly in flow cytometry, making it difficult to know how much of a B cell response is due to malaria, or how much is due to other immunological stimulators