Quantitative analysis of sugar composition in common fruits and locally prepared fruit juices from the University of Dodoma Tanzania and its nutritional and health implications

Abstract

This study quantified and compared the sugar composition of commonly consumed whole fruits and locally prepared fruit juicesat the University of Dodoma (UDOM). A total of 350 students (80.6%), aged 18–24 (60%), participated in the dietary survey. Sixty juice samples were collected from 20 local vendors for sugar analysis. Eight fresh fruits were homogenized and extracted using deionized water. The refractometer measured the total soluble sugars, confirmed by high-performance liquid chromatography (HPLC) for sucrose, glucose, and fructose. Bananas (20.6 g/100 g) and mangoes (18.5 g/100 g) had the highest natural sugar content, while avocados had the lowest (6.9 g/100 g). Sugar levels generally increased with the number of fruits in a blend, with three- and four-fruit combinations containing pineapple showing the highest total sugars (~ 8 g/100 mL). Juices with added sugar (sucrose > 60% of total sugar) reached up to 11 g/100 mL, especially in mango-pineapple blends. The paired-sample t-test showed significantly higher glucose in juice with added sugar (t (17.4027) = - 2.9482, p = 0.0088). ANOVA revealed significant differences in glucose (F = 8.90, p = 0.0074) and fructose (F = 8.13, p = 0.0096), but no significant difference in sucrose (F = 0.90, p = 0.4393).Among participants, 71.7% consumed whole fruits regularly, with a preference for mixed fruits. Similarly, 70.5% consumed fruit juice frequently, and 55.7% preferred mixed fruit juices. Vendor assessments showed 90% cleaned tools with tap water, 10% used disinfectants, and 15% reported inadequate waste disposal, emphasizing the need for health education. Mixed fruit juices were preferred over single fruit juices. Avocados had the lowest sugar content. Glucose and fructose dominated over sucrose in all fruit samples. Added sugar significantly increased total sugar levels in juices. Poor vendor hygiene practices and high juice consumption pose health risks.