PHYSICOCHEMICAL PROPERTIES OF GLUTEN-FREE PANCAKES FROM RICE AND SWEET POTATO FLOURS

Gluten‐free pancakes were prepared using rice flour and rice flour replaced with various amounts, at 10, 20 and 40%, of sweet potato flour. Textural properties of the cooked pancakes, such as hardness and chewiness generally increased with time after cooking, whereas they decreased with increased sweet potato flour replacement. On the other hand, cohesiveness decreased with time, but increased with increased sweet potato flour in the pancake. Nutritional properties of the rice–sweet potato pancakes, such as protein content, dietary fiber, total carbohydrate and calories were generally comparable with those of their wheat counterpart. The only significant difference was in the beta‐carotene content, which increased from 5.2 to 236.1 μg/g when sweet potato flour was incorporated, from 0 to 40%, into the rice pancake formulation.     

PHYSICOCHEMICAL PROPERTIES OF THREE RICE VARIETIES

Physicochemical properties of three rice varieties were studied. Textural properties of gels from La Grue, Bengal, and S201, were investigated using the Universal Texture Analyzer, and pasting characteristics by Brabender Visco/amylography. Gels from La Grue (long grain) had higher fracturability, hardness, amylographic consistency, and setback viscosity (P<0.05). Gels from S201, a short grain variety, were harder and had higher fracturability values than those from Bengal, a medium grain variety. Analysis of texture profiles of rice gels could be an alternative to Brabender viscoamylographs for differentiating among rice varieties. Tests on in-vitro starch digestibility showed that La Grue had lower maltose released than S201 or Bengal during the first 15 and 45 min of hydrolysis with human salivary α-amylase.     

INTERRELATIONSHIP BETWEEN CERTAIN PHYSICOCHEMICAL PROPERTIES OF RICE

Water uptake at 80°C and starch-iodine blue value at 65°C, both expressed as percentage of the respective parameter at 96°C gave good inverse estimates of the gelatinization temperature of rice. The equilibrium moisture content on soaking in water was 28–29s in indica , and 30–31% in dwarf indica and japonica rice. Similarly the fraction of total amylose soluble in water (96° C) was around 50% in indica and japonica , but 35% in dwarf indica. Dwarf indica rice viscogram showed a rather high setback value. The blue value of the excess cooking water of rice gave no useful information. Varieties with less than 25% amylose gave C-type alkali reaction.     

STUDIES ON THE PHYSICOCHEMICAL PROPERTIES OF MILKFISH MYOGLOBIN

Myoglobin (Mb) was isolated from the dark muscle of the milkfish (Chanos chanos) by Sephadex G‐75 gel filtration chromatography. The molecular weight of milkfish Mb is 15, 900 Da. The tristimulus color values (L, a and b) of Mb solutions changed significantly depending upon the form of Mb. With the formation of metmyoglobin (metMb), the L value increased gradually with the increase in the percentage of metMb, while a values decreased and Mb aggregation gradually increased along with incubation time. The autoxidation of milkfish Mb proceeded as a first‐order reaction, and the autoxidation rate constant increased with decreasing pH in a range of 5.5–7.0. The free energy for unfolding (Δ G_D) of Mb at acidic pH was smaller than at neutral pH, with values of 5.8 kcal/mol at pH 6.63 and 6.0 kcal/mol at pH 7.05. A higher rate of autoxidation and lower values of free energy were observed at acidic pH than at neutral pH.     

蜡质马铃薯淀粉的性质及应用

蜡质马铃薯淀粉具有比普通马铃薯和蜡质玉米淀粉更为优良特性。具有糊化温度低、膨胀容易,糊化时吸水、保水力大,糊液的粘度很高、透明度非常好,平均粒径大、粒径大小分布范围广等独特性质,蜡质马铃薯淀粉在食品工业具有广泛应用前景。     

PREDEHYDRATION STEAMING CHANGES PHYSICOCHEMICAL PROPERTIES OF UNRIPE BANANA FLOUR

Flour produced from steamed and unsteamed unripe bananas was analyzed to determine the effect of steaming on physicochemical properties. Steaming of bananas prior to dehydration slowed dehydration of banana slices, increased water uptake, density and solubility of flour and decreased viscosity, setback, breakdown, discoloration and vitamin C content. Banana flour produced with predehydration steaming gives pastes of low paste bulk density, which is desirable for weaning and supplementary foods.     

中国水牛奶理化性状研究

本研究对中国水牛奶的物理性质，化学成分作了系统的测定和分析，同时对中国水牛奶与摩拉水牛奶，中国荷斯坦牛奶的理化性状作了对比分析。结果是：中国水牛奶的总干物质，乳脂肪，乳蛋白质含量均显著高于摩拉水牛奶和荷斯坦牛奶；中国水牛含量比牛奶低，非脂固表物和钙的含量较牛奶高，其它成分含量和物理性状无显著差异。     

PHYSICOCHEMICAL PROPERTIES OF FOUR TOMATO CULTIVARS GROWN IN NIGERIA

The physicochemical characteristics of tomato fruits from three commercial cultivars available in the local market were compared with a Wild cultivar. The results showed that the Ibadan‐Local and Wild cultivars had a higher fruit yield than Ife‐1 and Roma‐VF cultivars. The Wild cultivar has a high skin and seed content. The shape of the fruits varied from spherical to pear‐like. Physicochemical properties such as specific gravity, pH, titratable acidity, ash and refractive index did not vary significantly while total solids, longitudinal (stem→blossom end) and cross‐sectional diameters (transverse diameter), vitamin C and reducing sugars were significantly different (P > 0.05) among the cultivars investigated. The results showed that the Wild cultivar has attributes (i.e., physicochemical characteristics) comparable to commercial cultivars to recommend it to breeders for cultivation.     

VARIABILITY IN PHYSICOCHEMICAL PROPERTIES OF DRIED WHEYS FROM COMMERCIAL SOURCES

Variability in physicochemical characteristics of dried wheys was determined for samples collected from six commercial sources. Eight dried whey samples were collected from each plant over a six month period. The pH in water, percent ash, alkalinity of ash, solubility in water and in acid, and Browning Indexes with and without pronase digestion were determined for each dried whey. Whey proteins were evaluated by gel electrophoresis. Variability of pH in water and of percent ash were low for dried wheys from individual plants, however considerable variability existed in the other characteristics, both between plants and between samples from individual plants. Gel electrophoresis may be useful in evaluating the effects of whey processing and drying on whey proteins.