Physical-Chemical Properties, Storage Stability and Sensory Evaluation of Pumpkin Seed Oil

Physico-chemical properties, storage stability and sensory evaluation of pumpkin seed oil was carried out and compared with other vegetable oils commonly used in Tanzania in order to evaluate its potential as an edible oil with the aim of promoting its utilization in rural areas. Pumpkin seeds were collected from different farmers in three villages in Morogoro Region, Tanzania. The proximate composition of the seeds was determined using standard methods. Storage stability of the oil was evaluated by monitoring the physicalchemical properties of the oil for 15 weeks following the standard procedures. Acceptability of the oil was determined using a 5 point hedonic scale. Pumpkin seeds contained 34.7%, 15.9%, 3.85% and 44% protein, fat, fibre and carbohydrates, respectively. The specific gravity of the pumpkin seed oil was 0.92; peroxide value 4.6 meq/kg; iodine value 108.4; saponification value 173.0 and acid value of 0.5 mg KOH/g. The pumpkin seed oil was organoleptically acceptable in terms of flavour, taste and odour. The pumpkin seed oil conforms very well with other common edible vegetable oils in Tanzania in terms of physical-chemical properties and sensory evaluation. Farmers should be encouraged to utilize pumpkin seed oil for household consumption.Key words: pumpkin seed oil, sensory acceptabilit

Nutritional status of underfive children in a pastoral community in Simanjiro District, Tanzania

A study was conducted in Simanjiro district in northern Tanzania to determine the nutritional status of underfive children in a pastoral community. Weight and height measurements were carried out on 250 children and that of mean upper arm circumference (MUAC) on 226 children. The z-scores of weight-for-age, weight-for-height and height-for-age indicated that 31.2% of the children were underweight and 6.0% were severely underweight. Wasting was observed in 17.2% children of whom 3.2% were severely wasted. Severely stunted children were 3.2% while 14% were moderately stunted. Measurements of MUAC indicated that 35% and 3.5% of the children were moderately and severely undernourished, respectively. The nutritional status of the children under study was slightly lower than the national average. In conclusion, malnutrition in Simanjiro district is prevalent, and therefore, appropriate multidisciplinary approach on nutrition education, environmental sanitation and hygienic practices at family and community level need to be promoted to reduce childhood illnesses thereby increasing child health and nutritional status. Keywords: nutrition, children, pastoral community, Tanzania Tanzania Health Research Bulletin Vol. 8(1) 2006: 32-3

Physico-chemical and grain cooking characteristics of selected rice cultivars grown in Morogoro

A study was carried out at Sokoine University of Agriculture to characterize the local rice varieties grown in Morogoro Region basing on their physical-chemical characteristics and cooking quality parameters. Five cultivars of rice were analyzed and these included Kaling'anaula, Kihogo Red, Salama M17, Supa and Salama. The samples were collected from Crop museum, SUA. The chemical analysis was done to determine the proximate composition, gelatinization temperature and gel consistency as main determinants of cooking quality, sensory evaluation tests was done as determinants for consumer acceptance. The proximate composition results indicated protein content values between 7.94 and 9.46%, ash content between 0.55 and 0.97%, fat content between 0.57 and 0.85%, fiber content between 0.29 to 0.73%. The amylose content values were between 18.25 and 19.25%. The gel consistency results showed that all cultivars analysed were hard with the gel length values between 27.50 and 31.80 mm There was a significant differences in composition as well as acceptability between the varieties. In all aspects, Supa cultivar appeared to be the most superior with mean score of 4.30 while Kihogo Red was the least superior with mean score of 2.93. The differences in the cultivars could be from environmental as well as genetic factors. This pauses a need for more studies to be directed to these factors in order to come up with useful alternatives on how to manipulate them so as to improve the cooking quality parameters, improve production of the local rice cultivars and increase the market demand for local rice. Tanzania Journal of Science Vol. 32 (1) 2006: pp. 29-3

Assessment of over time changes of moisture, cyanide and selected nutrients of stored dry leaves from cassava (Manihot esculenta Crantz)

Most fresh agricultural products are quickly perishable and various methods of preservation are necessary. Cassava leaves from different types of cassava (bitter, sweet and wild) were (1) dried un-pounded and (2) dried pounded in a tunnel solar dryer, filled in high density polyethylene material, sealed and placed into opaque cartons. The packing materials were purposively chosen to limit water, oxygen and light access. The complete drying was when samples were completely brittle. The storage was done at room temperature at Sokoine University of Agriculture, Morogoro, Tanzania. The main purpose of the study was to estimate shelf life by evaluating satisfactory quality in terms of nutritional values, dryness and organoleptic parameters. Water, cyanide, ascorbic acid, β-carotene, protein, iron, phosphorus, potassium and zinc were chemically analyzed at zero, three, six, nine and twelve months of storage. Dryness and organoleptic parameters were also evaluated at these different storage lengths. Processing procedure had significant effect only on water (p=0.0358), cyanide (p=0.0189) and β-carotene (p=0.0214) contents. Storage time affected water, cyanide, ascorbic acid, β-carotene, protein, iron, phosphorus, potassium and zinc significantly (p<.0001). Water content increased by 6.8% and ascorbic acid decreased to zero while β-carotene, protein, minerals and cyanide showed slight decline during the storage period. The optimum storage time under the conditions was judged to be six months for nutrients and organoleptic parameters stability.Keywords: Cassava leaves, solar drying, storage time, Rwanda.African Journal of Biotechnology, Vol 13(42) 4112-411

The Effect of Tempering on Strength Properties and Seed Coat Adhesion Strength in Sorghum and Millet

The effect of tempering on seed coat adhesion strength and mechanical strength of sorghum and millet grain kernels was investigated at different tempering durations. Tempering reduced the kernel breaking strength and had significant effect on seed coat adhesion strength. Tempering the grain for 60 minutes at ambient temperature (200C) reduced the force required to break the grain kernel from 148.4 N to 120.9 N for Dionje (a hard endosperm sorghum variety), 86 .0 N to 36.4 N for Jumbo (a soft endosperm sorghum variety) and from 51.4 N to 31.0 N for millet. The amount of energy absorbed at the breaking point of the grain kernel decreased from 52.5 mJ to 37.0 mJ for Dionje, 18.9 mJ to 13.0 mJ for Jumbo and from 14.0 mJ to 5.3 mJ for millet within the same tempering duration. Deformation at break point increased with increasing tempering duration from 0.28mm to 0.46 mm for Dionje, 0.27 mm to 0.48 mm for Jumbo and from 0.21mm to 0.35 mm for millet. Tempering for 15 minutes reduced the seed coat adhesion strength per unit area by 87.6% for Dionje, 94.7% for Jumbo and 95.7% for millet compared to untempered grain. This indicated that tempering of sorghum and millet before dehulling could reduce both the dehulling time and losses incurred during the dehulling process leading to a substantial improvement in their dehulling efficiency. Journal of Agriculture, Science and Technology Vol.4(1) 2002: 1-

The effect of moisture on physical properties of sorghum and millet

Knowledge of how the physical properties of grain vary with changes in moisture content is one of the prerequisites for the design and development of efficient processing and handling machines for the grains. Physical properties of two varieties of sorghum (Dionje and Jumbo) and one variety of pearl millet (IM) were investigated at different moisture levels within the moisture range 12 to 25% dry basis. Grain samples with different moisture levels were obtained by adding calculated amounts of distilled water to the grain, mix thoroughly and seal the samples in polythene bags and keep them in refrigerator at 5°C for fourteen days to allow moisture to distribute uniformly within the sample. The results showed that within this moisture range, all the physical properties studied varied linearly with moisture content. Linear dimensions (length, width and thickness), geometrical mean diameter, sphericity, surface area, volume, kernel density and porosity increased with increase in moisture content of the grain. On the other hand, bulk density decreased with increase in moisture content of the grain. Journal of Agriculture, Science and Technology Vol. 7(1) 2005: 30-4

The effect of moisture on physical properties of sorghum and millet

Knowledge of how the physical properties of grain vary with changes in moisture content is one of the prerequisites for the design and development of efficient processing and handling machines for the grains. Physical properties of two varieties of sorghum (Dionje and Jumbo) and one variety of pearl millet (IM) were investigated at different moisture levels within the moisture range 12 to 25% dry basis. Grain samples with different moisture levels were obtained by adding calculated amounts of distilled water to the grain. Mixing was done thoroughly, the samples sealed in polythene bags and kept in refrigerator at 5oC for fourteen days to allow moisture to get distributed uniformly within each. The results showed that within this moisture range, all the physical properties studied varied linearly with moisture content. Linear dimensions (length, width and thickness), geometrical mean diameter, sphericity, surface area, volume, kernel density and porosity increased with increase in moisture content of the grain. On the other hand, bulk density decreased with increase in moisture content of the grain. Journal of Agriculture, Science and Technology Vol. 8 (1) 2006: pp. 43-5

Evaluation of Bacteriological Stability of Minced Canned Meat Stored Under Simulated Tropical and Subtropical Conditions

Thermal inactivation of spoilage microorganisms is one of the widely used commercial food preservation techniques. However, its application may be too costly in terms of energy expenditure or inappropriate in terms of product quality. In this study, an attempt was made to produce tropical storage stable canned meat using remarkably milder heating effects than those commonly used by food processors. Canned beef in its own juice was used as a model product and Bacillus stearothermophilus (Merck Art No. 11499), Clostridium sporogenes (ATCC 10000) and Clostridium thermosaccharolyticum (ATCC 7956) as reference strains. The raw minced meat used for the formulation of the product was contaminated with spores of the aforesaid strains at 104-106 spores/g prior to the heat treatment. The heating effects (Fc – values) were measured throughout the experiment at the geometrical middle point (GMP) of the can. The canned meat was thereafter stored up to six months under simulated tropical and subtropical temperatures of 55oC and 25oC respectively, followed by bacteriological investigations. Results showed that C. sporogenes is of no significance in the production of tropical storage stable canned meat products. This strain was eliminated by Fc = 3.0 even at a very high contamination level of 106 spores/g. At the same level of contamination, heating values of Fc = 13.0 and 16.0 were needed to eliminate spores of C. thermosaccharolyticum and B. stearothermophilus, respectively. At a reduced contamination level of 104 spores/g Fc values of 11.0 and 15.0 were necessary to completely eliminate the same bacteria, respectively. Addition of 0.4 % benzoic acid resulted into reduction of the Fc – value from 16.0 to 13.0 for the elimination of B. stearothermophilus at 106 spores/g contamination level. Adding the same amount of citric or acetic acid was enough to lower the heating value further to 11.0. Potassium sorbate was ineffective in increasing the heat sensitivity of B. stearothermophilus even at a concentration of 4 % in the minced meat. It was concluded that the heating effects (Fc – values) recommended for the production of tropical stable and safe meat products are applicable only for highly contaminated raw meat. Fc – values of 16 and above given by some authors seem to be on the higher side. Observing hygienic practices in handling of the raw meat could significantly (