Although breeders have made significant progress in the genetic improvement of cassava (Manihot esculenta Crantz) for agronomic traits, lack of information on heritability and limited testing of highthroughput phenotyping methods are major limitations to improving root quality traits, such as softness after cooking, which rank high among Ugandan consumers. The objectives of this study were to determine heritability for softness of cooked cassava roots, and quantify the relationship between penetrometer and consumer testing methods for phenotyping softness of cassava roots. Softness defined as the maximum force (N) needed to penetrate cooked root samples using a penetrometer, was evaluated at four cooking time intervals: 15, 30, 45, and 60 min on 268 cassava genotypes. Estimates of broad-sense heritability (repeatability) ranged from 0.17 to 0.37, with the highest value observed at 45 min of cooking time interval. In the second study involving 135 cassava consumers from Kibaale district in Uganda, penetrometer measurements of cooked roots from six cassava varieties were found to be in strong agreement (r 2 = 0.91; P-value = 0.003) with ordinal scores of root softness from consumer testing. These results suggest that: (a) softness of cooked cassava roots is a trait amenable for evaluation and selection; and (b) a penetrometer can readily be used for assessment of cooked root softness. These findings form the basis for operationalising the routine assessment of root softness in cassava breeding trials, an output that will enhance ongoing efforts to breed for desired end-user root quality traits.

The study characterized heterogeneous biocatalyst synthesized from sucrose, saw dust, and chicken egg shells using Fourier Transform Infrared (FTIR) spectroscopy coupled with Attenuated Total Reflectance (ATR) technique. Acidic sulphonate (–SO3H) groups were more visible in the spectrum generated for carbonized and sulphonated sucrose than in carbonized and sulphonated saw dust. This was highlighted further by the significantly higher conversion percentage achieved for sulphonated sucrose (62.5%) than sulphonated saw dust (46.6%) during esterification of expired sunflower oil (p=0.05). The spectra for calcinated egg shells also showed that the most active form of calcium oxide was produced at calcination temperature of 1000°C. This was confirmed in the single-step transesterification reaction in which calcium oxide generated at 1000°C yielded the highest biodiesel (87.8%) from expired sunflower oil. The study further demonstrated the versatility of the FTIR technique in qualitative analysis of biodiesel and regular diesel by confirming the presence of specific characteristic peaks of diagnostic importance. These findings therefore highlight the potential of FTIR-ATR as an inexpensive, fast, and accurate diagnostic means for easy identification and characterization of different materials and products.

Provitamin A cassava clones were analysed for starch yield and critical starch quality attributes, to understand possible applications in the food industry. Total carotenoids content in the test clones ranged from 0.03-11.94 μg g-1 of fresh root. Starch yield ranged from 8.4-33.2 % and correlated negatively (r = -0.588, P < 0.001) with carotenoids content. Amylose content (16.4–22.1%) didn't differ significantly (P ≤ 0.05) among the cassava clones. Meanwhile, total carotenoid content had significant negative correlations (P ≤ 0.05) with starch pasting temperature, peak time, setback viscosities and peak area. The reduced peak time and pasting temperatures in high-carotenoid cassava signifies reduction in energy requirements in yellow-fleshed roots when compared to white-fleshed cassava. This attribute is desirable for the food industry as it would reduce the overall cost of processing the cassava. Furthermore, final viscosities of starch from carotenoid-rich cassava were lower than those of white-fleshed roots, making provitamin A cassava suitable for soft food processing.

The threat posed by plastics to the environment has prompted the development of bioplastics. Starch plasticized by glycerol is a key renewable resource in the production of high-quality bioplastics. Previous studies have availed information on the mechanical quality of starch-based bioplastics however there is limited information about their degradation pattern in the natural environment which this research presents. Bioplastics were buried in holes in loam sandy soil and weekly photographic data and weight were collected to reveal the effect of degradation. Weather parameters of rainfall, temperature, relative humidity, sunshine intensity and sunshine hours were recorded to establish influence of weather on degradation. A control set up in the laboratory was used to compare the results. Over time the tests revealed that as the hydrophilic enzymes break down the bioplastic, its weight initially increases (up to 87%) due to absorption of moisture and after saturation, the bioplastic is disintegrated which initiates decomposition and the bioplastic weight is steadily reduced. Degradation was further enhanced by invasion of soil organisms like worms, termites among other soil microbes. Rainfall (r = 0.857) increased the moisture in the soil which initially increased the weight of the bioplastic up to a point when the hydrophilic enzymes set into breakdown the bioplastic then the weight started to drop. This was the same case for relative humidity (r = −0.04) however; the sunlight intensity (r = 515) and hours of illumination indirectly affect the process by influencing microbial activity. An increase in the sunshine intensity increased the activity of soil organisms up to a point beyond which increased exposure caused the organisms to burrow deeper in the soil. Increase in microbial activity increased the rate of degrada-How to cite this paper: AhimbisibweJournal of Agricultural Chemistry and Environment tion of the buried bioplastics which took five to ten weeks to fully decompose (98.3%). The reduced time of degradation means that starch-based bioplastics have a high potential as sustainable substitute for petroleum-based plastics.