Nanoscale properties of collagen in ageing

Collagen is the most abundant structural protein in the human body. It is highly conserved across species and is found in our skeleton, tendons, cornea, and skin for example. Although collagen has been widely studied over the past 30 years, the relationship between its structural behaviour and its mechanical properties with ageing still remains poorly understood especially at the molecular level (nano-scale). This research looks at a novel approach to quantify the effects of collagen cross-linking due to ageing at the molecular scale by using both engineered / aged biomimetic collagen matrices. This is an inter-disciplinary approach integrating fields of nanotechnology, tissue engineering and systems biology

EFFECT OF GERMINATION ON PROXIMATE COMPOSITION, MINERAL BIOAVAILABILITY AND FUNCTIONAL PROPERTIES OF AFRICAN YAM BEAN SEED FLOUR

The effects of germination on the quality attributes of African yam bean (Sphenostylis stenocarpa) seed, an underutilized legume were investigated. The seeds were subjected to germination at 25 ºC for 24 h, 48 h, 72 h and 96 h after which they were dried, milled into flour and the effects of germination on the proximate composition, anti-nutritional contents, mineral bioavailability and the functional properties of the flour samples were determined. The protein contents of the germinated flour samples ranged between 20.3 and 21.3% with highest value recorded after 24 h of germination. The fat content, ash content and the crude fibre of the germinated flour samples ranged from 2.27- 2.67%, 3.47 -3.80 and 2.10 - 2.67%, respectively. The fat and the crude fibre decreased with the geminating period while the ash contents increased. There was a general increase in the mineral availability with increase in germination period. Calcium content increased from 48.33 to 51.67 mg/100 g; iron content from 6.23 to 6.43 mg/100 g; magnesium from 41.67 to 48.33 mg/100 g; and phosphorus from 141.67 to 146.67 mg/100 g. There were reductions in the anti-nutritional contents of the flour samples with the germinating process.  There was about 50% reduction in oxalate content; 35% reduction in phytate and 100% in trypsin inhibitor content. The germination process had effects on the swelling capacity, foam capacity and water absorption capacity of the flour samples. The bulk density ranged between 0.67 and 0.71 g/cm3; water absorption capacity from 196.67% to 178.33%; swelling capacity from 1.77-1.50%; and foaming capacity 39.43-31.57%. Germination of African yam bean seed had effects on the proximate composition, functional properties, reduction of the anti-nutritional content and increment on the bioavailability of some minerals which could help to increase the potential of this underutilized crop in food products

Mechanical Properties and Microstructural Characterization of Aged Nickel-based Alloy 625 Weld Metal

The aim of this work was to evaluate the different phases formed during solidification and after thermal aging of the as-welded 625 nickel-based alloy, as well as the influence of microstructural changes on the mechanical properties. The experiments addressed aging temperatures of 650 and 950 A degrees C for 10, 100, and 200 hours. The samples were analyzed by electron microscopy, microanalysis, and X-ray diffraction in order to identify the secondary phases. Mechanical tests such as hardness, microhardness, and Charpy-V impact test were performed. Nondestructive ultrasonic inspection was also conducted to correlate the acquired signals with mechanical and microstructural properties. The results show that the alloy under study experienced microstructural changes when aged at 650 A degrees C. The aging was responsible by the dissolution of the Laves phase formed during the solidification and the appearance of gamma aEuro(3) phase within interdendritic region and fine carbides along the solidification grain boundaries. However, when it was aged at 950 A degrees C, the Laves phase was continuously dissolved and the excess Nb caused the precipitation of the delta-phase (Ni3Nb), which was intensified at 10 hours of aging, with subsequent dissolution for longer periods such as 200 hours. Even when subjected to significant microstructural changes, the mechanical properties, especially toughness, were not sensitive to the dissolution and/or precipitation of the secondary phases

Quality evaluation of chinchin produced from composite flours of wheat and germinated finger millet flour

Composite flour was produced from germinated finger millet and wheat and its potentials in producing nutritious chinchin, a traditional Nigerian snack was investigated. Finger millet was sorted, germinated, dried and milled into flour. Simplex Lattice Designs was used in generating different formulations (100:0, 88:12, 75:25 and 50:50) of wheat and germinated finger millet, respectively, and used to produce chinchin. The composite flour was analyzed for proximate, minerals, antinutritional and functional properties while the chinchin samples were subjected to sensory evaluation. The values obtained for moisture, protein, fat, crude fibre, ash and carbohydrate were in the ranges of 10.47 to 10.71%, 8.74 to 9.64%, 1.79 to 1.95%, 1.38 to 1.55%, 2.31 to 2.57, 73.58 to 75.31%, respectively. The loose and packed bulk density ranged from 0.61 to 0.62 g/cm3 and 0.005 to 0.013 g/cm3. The calcium, iron, magnesium, potassium and phosphorus content of flour ranged from 0.1150 to 0.1300 mg/l, 12.033 to 13.633 mg/l, 0.158 to 0.187 mg/l, 0.389 to 0.428 mg/l and 0.271 to 0.296 mg/l, respectively. The anti-nutritional properties reduced with processing. This study has shown the potentials of composite flour from wheat and germinated finger millet in production of nutritious chinchin. Keyword: Finger millet, wheat flour, chinchin, snacks, composite flou

Physical and Sensory Properties of Bread Made with Wheat and Fermented Finger Millet (Eleusine coracana L.) Flours

Aim: The study was conducted to determine the effect of fermented finger millet flour supplementation in wheat on the physical and sensory properties of bread. Methodology: Finger millet grains were cleaned, washed and fermented in deionized water for 72 h at room temperature (27±2oC), with sampling at every 24 h interval. Fermented grains were washed, drained, dried (65oC, 4 h), milled and sieved (<250 µm) to produce Fermented Finger Millet Flour (FFMF). Composite flour was formulated by supplementing wheat flour with Fermented Finger Millet Flour (FFMF) at 0, 5, 10, 15 and 20 % (w/w), and used to produce bread samples. Physical (Oven spring, loaf weight, loaf volume and specific volume) and sensory (crust colour, crumb colour, aroma, texture, taste, mouth feel and overall acceptability) properties of the bread samples were determined. Results: Physical properties showed less oven spring, loaf volume and specific loaf volume and increased loaf weight with increased FFMF replacement. The sensory analysis showed significant differences (p<0.05) between 100% wheat bread and FFMF supplemented samples in all the determined sensory properties. It was concluded that fermentation period of 24-48 h, and substitution of 5-10% FFMF into wheat gave the bread samples with the best overall acceptability

Potentials of Pigeon Pea-wheat Flour Mixes in Bread Production

It is considered that pigeon pea (Cajanus cajan) has higher and more balanced protein than most of the other legumes. However, protracted cooking time, antinutritional constituents and dehulling constraints are responsible for its underutilisation in the developing countries. In this study, pigeon pea was processed into flour using different processing methods (Soaking, Sprouting, and Roasting), and subsequently used as a wheat flour supplement for baking bread. The bread was analysed for the proximate composition, physical and sensory attributes. The proximate composition analysis indicates more protein (17.73-18.51%) and ash (3.50-3.73%) contents in the bread produced with 20% substitution of the sprouted pigeon-pea-wheat flour than others. Loaf volume, specific volume, oven spring, crumb hydration and bread strength increased whereas a decreasing trend was observed for density with the increasing substitution percentage. Sensory results showed that substitution levels at 5 and 10% with soaked and roasted pigeon pea flour gave the highest rating while bread samples with sprouted pigeon pea flour had the lowest rating. The study has established that sprouted pigeon pea-wheat flour mixes have more nutritional potentials. As per the sensory analysis indices 5-10% substitution levels of the soaked and roasted pigeon peas are acceptable at p<0.05. Conclusively, utilisation of pigeon pea in the human diet as a source of plant protein has potentials of combating malnutrition problems especially among the vulnerable people of the developing countries