It is difficult for many Rwandans to utilize climbing bean seeds ( Phaseolus vulgaris . L) mainly because of longer cooking time (2 hours) and the high consumption of basic fuel. Climbing beans also contain anti-nutritional factors such tannins, phytates, trypsin inhibitors and phytohemagglutinins that limit nutrient absorption. One way to solve this problem is to utilize the flour of climbing beans made from different treatments and processing methods. In this study, climbing beans were pre-treated by soaking them in water for 24 hours, soaking in 2% sodium bicarbonate solution and steam blanching for 10 minutes. After that, pre-treated climbing beans were processed into flours by processing methods such as roasting, cooking and germination where anti-nutritional factors were reduced. The pretreatments did not significantly (p>0.05) affect phytates in climbing bean flours but processing conditions significantly (p<0.05) reduced it. Pretreatments and processing conditions significantly (p<0.05) reduced tannin content. The pretreatments followed by different processing conditions significantly (p<0.05) decreased trypsin inhibitors content. The great significant decrease in phytohemagglutinins content was observed in pretreatment followed by different processing methods. All pretreatments and processing conditions effectively decreased anti-nutritional factors at low level. However, pretreatments or untreated followed by germination and roasting were found to be the most and the least effective respectively. Making flour from germinated climbing bean seeds is a good option for sustainable food processing as it reduces anti-nutritional factors. It is an inexpensive method in terms of time, energy and fuel for Rwandan households, restaurants and industries where climbing bean seeds are integral part of daily meal.
This chapter presents the History, origin and taxonomy of cocoa. Chocolate is derived from the cocoa bean, which is obtained from the fruit of the cocoa tree, Theobroma cacao (Linnaeus). Cocoa continues to be an important source of export earnings for many producing countries, particularly in Africa, Latin America and South-East Asia. The chapter describes the morphological and varietal characteristics of cocoa. The different cocoa bean genotypes or varieties discussed in the chapter influence both flavour quality and intensity in chocolate during manufacturing. The differences are largely due to the wide differences in the chemical compositions of the derived beans, likely determining the quantities of flavour precursors and activity of enzymes and thus contributions to flavour formation. Varietal differences were primarily due to quantitative (as opposed to qualitative) differences in flavour precursor and polyphenol contents. The chapter finally discusses the concept of this book.
This chapter investigates changes in microstructure, appearance, texture and melting characteristics during blooming in under-tempered dark chocolates varying in particle size distribution and to explain the possible mechanism leading to fat bloom development in products. The rate of bloom development in under-tempered dark chocolate was dependent on the solids particle size distribution (PSD) and storage time. Changes during blooming were attributed primarily to growth of new fat crystals within the structural network with changes in light reflections yielding increases in surface whiteness and hardness. The chapter concludes that bloom development was initiated by movement of liquid and unstable fat onto product surfaces through capillarity created by hydrodynamic forces within the inter-particle pores and crevices, followed by growth of new fat crystals promoted by diffusion gradients across the mass until the chocolate was fully bloomed. Understanding fat bloom formation and development in dark chocolate has potential applications in new product development.
AbstractResponse surface methodology (with central composite rotatable design for k=3) was used to investigate the product properties of extruded rice–cowpea–groundnut blends in a single screw extruder. The combined effect of cowpea (0–20%), groundnut (0–10%), and feed moisture (14–48%) levels were used for formulation of the products. The product moisture, expansion ratio, bulk density and total colour change were studied using standard analytical methods. Well-expanded rice–legume blend extrudates of less bulk density and lower moisture content were produced at low feed moisture. Increasing legume addition affected the various shades of colour in the product. Models developed for the indices gave R2 values ranging from 52.8% (for the b-value) to 86.5% (for bulk density). The models developed suggested that the optimal process variables for the production of a puffed snack with an enhanced nutrition and spongy structure from a rice–cowpea–groundnut blend are low feed moisture of 14–20% and maximum additions of 20% cowpea and 10% groundnut. A lack-of-fit test showed no significance, indicating that the models adequately fitted the data.
This study describes the occurrence and profile of eight polycyclic aromatic hydrocarbons (PAHs) in fresh and cooked processed cowhide (wele) singed with different fuels. It also assessed the health risks associated with the consumption of this popular delicacy. The 8PAHs were all detected in the wele samples singed with scrap tires, whereas 5 and 3 carcinogenic PAHs were detected in the firewood and liquefied petroleum gas (LPG) singed wele, respectively. For each of the specific PAH detected, the contents in the wele samples were generally ranked as scrap tires > firewood > LPG. The average concentrations of benzo[a]pyrene for cooked wele samples were 2.75 ng g−1(firewood) and 22.85 ng g−1(scrap tires); exceeding the 2.0 ng g−1 European Commission regulation maximum levels (MLs) for smoked products. For the carcinogenic risk exposure assessment, the dietary intake based on benzo[a]pyrene equivalents was estimated as 777.06 ng g−1 day (scrap tires), 101.52 ng g−1 day (firewood) and 9.45 ng g−1 day (LPG). The probable cancer risk estimated considering the consumption frequency and quantity of wele for an average adult consumer was highest in the population exposed to wele singed with scrap tires (3.11×10−5).
