Nutritional enhancement and biochemical effects of citrus waste dietary fibre in wistar albino rats fed fortified doughnuts

Abstract

Dietary fibre extracted manually from citrus wastes of orange, white grapefruit, red grapefruit, and lemon was used to fortify doughnuts as a potential solution to non-communicable diseases. Sixteen Wistar albino rats equally divided into four groups were fed the fibre-fortified doughnuts ad libitum for 28 days at 25, 15, and 0 % fibre inclusion; and another control group fed standard rat pellets. Nutritional, microbiological, and sensory properties were examined on doughnuts while the rats' weight and biochemical indices were assessed after feeding. Obtained data was statistically analysed using ANOVA and post-hoc tests. Proximate analysis of the doughnuts revealed moisture range (4.06–10.21 %), ash (1.87–2.09 %), fibre (0.01–0.26 %), fat (6.67–35.84 %), protein (10.17–16.37 %), and carbohydrate (46.81–64.68 %) with the significantly (p < 0.05) highest crude fibre (0.26 %) in 25 % sample, showing improvement over regular doughnuts for gut health. Microbiological analysis showed safe TVB counts (7.0 × 10³–8.0 × 10⁴ CFU/g) and the absence of pathogens, supported by low moisture. Sensory assessment rated the fibre-fortified doughnuts in the range of 6–7 on a 9-point hedonic scale, indicating high acceptability. Average rats’ blood glucose ranged 61–79 mg/dL; 18.37–114.80 mg/dL in atherogenic lipid profiles (TC, TG, VLDL-C, and LDL-C) were lowest in 25 % fibre group and highest in HDL-C of the range (7.16–19.00 mg/dL), showing the most efficient in lowering blood glucose and atherogenic lipid profiles in the experimental rats compared to the control groups and better performance than the 15 % fibre doughnut. Thus, 25 % citrus fruit-waste-fibre-fortified doughnuts could be a nutritionally enhanced fast-food option to lower the risks of cardiovascular disease and diabetes.