Prevalence of overweight and obesity among children aged 6-12 years in Dodoma and Kinondoni municipalities, Tanzania.

A cross-sectional comparison study was conducted to determine the prevalence of overweight and obesity among schoolchildren 428 children aged 6 -12 years in Dodoma and Kinondoni municipalities in Tanzania. Anthropometric and body composition measurements were taken for all respondents. A total of 428 children were involved in the study. The prevalence of obesity among children aged 6 - 9 years in Dodoma and Kinondoni were 5.6% (n = 118) and 6.3% (n = 87), respectively. Likewise, 4.2% (n = 118) of children aged 6-9 years in Dodoma were overweight while 8.6% (n = 87) of their counterparts in Kinondoni municipality were overweight. For children aged 10-12 years, 3.9% (n= 118) in Dodoma were obese compared to 5.8% (n = 87) of their peers in Kinondoni. Some 4.9% of the children aged 10-12 years in Dodoma were overweight compared to 5.8% of their counterparts in Kinondoni. The average body fat mass of children aged 6 - 9 years in Dodoma ranged from 21.42-21.81%, while that of their peers in Kinondoni ranged from 21.66-21.98%. The average body fat mass of children aged 10-12 years ranged between 23.95-24.10% in Dodoma and 23.65-24.95% in Kinondoni. There were gender and age differences in body fat mass distribution, with girls and the older children having significantly (P < 0.05) higher proportion of body fat mass. In conclusion, although the prevalence of overweight and obesity among children in this study were lower than those reported elsewhere, there is an imminent danger because the trend of the conditions is rising swiftly with urbanization, changes in lifestyles and socio-economic transition. It is recommended that, children should be educated on good nutrition practices and trained to develop healthy eating behaviours. Parents should encourage lifestyle behaviours that promote high level of physical activities. Physical education and organized sports at schools should be revived.

Traditional alcoholic beverages of Tanzania: production, quality and changes in quality attributes during storage.

Traditional alcoholic beverages of Tanzania play an important role in the daily social, economic, nutritional and cultural life of the people. Production, quality and changes in quality attributes during ambient temperature storage were investigated in traditional Tanzanian beers (Mbege and Komoni) and wines (Mnanasi, Wanzuki and Mofru). The quality attributes of the alcoholic beverages indicated that pH levels were in the range of 4.15-4.20 and 3.9-5.5 for the beers and wines respectively. Total, fixed and volatile acidity in the beers were in the range of 0.41-0.62, 0.28-0.38 and 0.06-0.09 g/100 mL respectively while in the wines acidity levels were in the range of 0.23-0.66, 0.13-0.33 and 0.05-0.06 g/100 mL for the total, fixed and volatile acidity respectively. Concentration of total solids in the beers ranged between 7.00 and 12.80 degrees Brix while in the wines ranged between 3.45 and 6.65 degrees Brix. Specific gravity of the beers ranged between 1.0097 and 1.0374 while for wines the specific gravity was lower, ranging between 0.9971 and 0.9989. Alcohol concentration was higher in wines (range 3.84-9.75 g/100 mL) than in beers (range 1.72-2.76 g/100 mL). Storage of the beverages under ambient temperatures for various lengths of time resulted in significant (P < 0.05) increase in total acidity, volatile acidity and alcohol content and decrease in the total solids and specific gravity. Mbege and Komoni beers indicated the highest rates of deterioration with total acid production rates of 0.3774 g/100 mL and 0.0914 g/100 mL per hour respectively. Wines were more stable during storage than beers, with Mofru wine being the most stable. The rates of total acid production per hour were Mnanasi (0.0196 g/100 mL), Wanzuki (0.0047 g/100 mL) and Mofru (0.0005 g/100 mL). Use of low brewing technologies involving uncontrolled fermentation, unsanitary conditions and use of rudimentary equipment for processing, packaging and storage resulted in beers and wines of low quality and short shelf-life. To foster commercial exploitation of the products, there is a need to develop appropriate small and medium-level brewing technologies that will improve the quality of the traditional alcoholic beverages and extend their shelf-life through hygienic and controlled processing, packaging, and storage.

Nutritive value and effect of blanching on the trypsin and chymotrypsin inhibitor activities of selected leafy vegetables.

Proximate composition, energy, mineral and vitamin contents and the effect of blanching methods and times on the trypsin and chymotrypsin inhibitor activities were studied using cabbage, collard, turnip, peanut, and sweet potato leaves. Results of this study indicated that, crude protein, crude fat, carbohydrate and ash contents were in the range of 15.5-25.6%, 1.4-6.5%, 60.4-73.1% and 6.8-7.5%, respectively. Total dietary fiber was lowest in cabbage (28.2 g/100 g) and highest in the collard leaves (43.1%) while energy content per 100 g of vegetables was highest in sweet potato leaves (402 kcal) and lowest in cabbage (379 kcal). The mineral content per 100 g of vegetables were in the range of 33.4-249.8 mg, 241.2-471.2 mg, 12.1-75.1 mg, 14.9-98.9 mg, 0.5-3.5 mg and 0.9-3.1 mg for Ca, K, Na, Mg, Fe and Zn, respectively. For ascorbic acid, riboflavin, thiamin and total carotenoids, concentrations in 100 g of vegetables were in the range of 45.1-112.7 mg, 0.2-0.3 mg, 0.3-0.8 mg and 2.0-7.3 mg, respectively. The trypsin inhibitory activity per gram of the vegetables was highest in collard (60.1 TIU/g) and lowest in peanut leaves (41.0 TIU/g). Chymotrypsin inhibitor activity was highest in the peanut (69.6 CIU/g) but lowest in the collard leaves (48.0 CIU/g). Both trypsin and chymotrypsin inhibitor activities were significantly (p < 0.05) reduced by most of the treatments in either the conventional or microwave blanching methods. In the conventional blanching method, trypsin inhibitor activity was reduced by 0.5, 6.8, 11.9, 9.0 and 19.3 percent in cabbage, collard, turnip, sweet potato and peanut leaves, respectively, when the vegetables were blanched for 2.5 minutes but after blanching for 10 minutes, the trypsin inhibitor activity was reduced by 29.7, 34.9, 54.3, 52.3 and 65.6 percent in cabbage, collard, turnip, sweet potato and peanut greens, respectively. For the microwave oven blanching, trypsin inhibitor activity was reduced by 3.8, 3.3, 32.7, 5.0 and 9.5 percent in cabbage, collard, turnip, sweet potato and peanut leaves, respectively when the vegetables were blanched for 30 seconds. When blanched for 60 seconds, trypsin inhibitor activity was reduced by 16.2, 45.8, 46.2, 51.0 and 42.4 percent in cabbage, collard, turnip, sweet potato and peanut greens, respectively. Similar trends in the reduction of chymotrypsin inhibitor activity were observed when the vegetables were conventionally blanched for 2.5, 5 and 10 minutes and when blanched by microwave oven for 30, 45 and 60 seconds. Based on the results of this study, the vegetables were good dietary sources of minerals, vitamins, carbohydrate and proteins. Also, blanching was an effective method for reducing the trypsin and chymotripsin inhibitor activities in the leafy vegetables, however, further investigation on the heating times for both conventional and microwave blanching methods is suggested.

Effect of traditional processing practices on the content of total carotenoid, beta-carotene, alpha-carotene and vitamin A activity of selected Tanzanian vegetables.

The alpha-carotene, beta-carotene and total provitamin A carotenoids and the effect of traditional processing practices on the retention of these provitamins were studied using amaranth, cowpea, peanut, pumpkin and sweet potato leaves. Results of this study indicated that the content of total carotenoids, beta-carotene and alpha-carotene were in the range of 26.79-44.74 mg, 4.16-19.12 mg, and 0.99-10.26 mg per 100 g of dry vegetables, respectively. The vitamin A activities were 4.042, 3.124, 0.829, 2.025 and 1.581 mg RE per 100 g of dry amaranth, cowpea, peanut, pumpkin and sweet potato leaves, respectively. The traditional processing practices of sun drying and storage in ventilated containers resulted in a significant (p < 0.05) decrease in the concentration of total carotenoids, beta-carotene and alpha-carotene for all the vegetables. Conventional blanching and cooking resulted in a significant (p < 0.05) increase in the concentration of carotenoids in the cowpea, peanut and pumpkin leaves while in amaranth and sweet potato greens, thermal processing resulted in a significant (p < 0.05) decrease in the concentration of these nutrients.

Proximate composition and mineral content of selected Tanzanian vegetables and the effect of traditional processing on the retention of ascorbic acid, riboflavin and thiamine.

Proximate composition, mineral content and the effect of traditional processing practices on the retention of ascorbic acid, riboflavin and thiamine were studied using amaranth, cowpea, peanut, pumpkin and sweetpotato leaves. Results of this study indicated that, crude protein, crude fat, carbohydrate and ash contents were in the range of 20.64--46.56 percent, 2.57--4.34 percent, 35.43--63.50 percent and 8.92--15.69 percent respectively. The mineral content per 100 g of fresh vegetables was in the range of 83.64--229.34 mg, 145.97--780.19 mg, 11.5--2l.31 mg, 43.02--110.30 mg, 0.96--5.90 mg and 0.40--2.24 mg for Ca, K, Na, Mg, Fe and Zn respectively. For ascorbic acid, riboflavin and thiamine, concentrations in 100 g of fresh vegetables were in the range of 43.78--89.00 mg, 0.62--1.71 mg and 0.09--0.30 mg respectively. The traditional processing practices of sun/shade drying and storing in ventilated containers resulted in a significant (P <0.05) decrease in ascorbic acid, riboflavin and thiamine for all vegetables. Conventional blanching and cooking for up to 15 minutes resulted in a significant (P <0.05) increase in riboflavin content in cowpea, peanut and pumpkin greens while in amaranth and sweetpotato leaves, thermal processing resulted in a significant (P <0.05) decrease in the vitamin. Based on the results of this study, the vegetables were good dietary sources of minerals, carbohydrate and protein.

Effect of blanching on the content of antinutritional factors in selected vegetables.

The effect of blanching on the antinutritional content was studied in cabbage, turnip, collard, sweetpotato and peanut leaves. All the vegetables contained various amounts of phytic acid, tannic acid and/or oxalic acid. Tannic acid was found in largest amounts ranging from 1266.00 mg/100 g in cabbage to 491.00 mg/100 g in sweetpotato. Phytic acid content ranged from 0.31 mg/100 g in sweetpotato to 3.97 mg/100 g in collard. Oxalic acid was in trace amounts in cabbage and turnip; but high concentrations were found in sweetpotato (469.67 mg/100 g) and peanut greens (407.00 mg/100 g). Levels of both tannic acid and phytic acid were significantly (p < 0.05) reduced by conventional and microwave blanching methods while oxalic acid levels were not significantly (p < 0.05) reduced in most of the treatments by either of the blanching methods. In general, blanching is recommended as an effective method for reducing the antinutritional factors in green vegetables, however, further investigation on the heating times for both conventional and microwave blanching methods has been suggested.