ASSESSMENT OF THE HYPOCHOLESTEROLAEMIC EFFECT OF A FERMENTED CONDIMENT (IRU) IN WISTAR RATS.

Abstract

Fermented food condiments form an integral part of African diets as they supply nutrient with claimed medicinal properties. This research was designed to investigate the effect of the use of different starter culture for fermentation on the bacteriological, nutritional and sensory qualities; as well as the hypocholesterolaemic effect of fermented Parkia biglobosa seeds (iru) in hypercholesterolaemic Wistar rats. Bacteria were isolated from Parkia biglobosa seeds fermented naturally, identified and used as using starter cultures for iru production from African locust beans seeds. Proximate, anti-nutritional, antioxidant, mineral, amino and fatty acids composition of the natural and starter culture produced iru were assessed using standard methods. The various ‘iru’ samples were then fed to hypercholesteroleamic rats for 28 days. The blood cholesterol, toxicological, haematological and histopathological parameters were assessed in the iru fed rats. The bacteria isolated from the naturally fermented iru were B. subtilis, Lactobacillus plantarum, and Leuconostoc mesenteroides. The proximate composition of the seeds showed that the highest protein value was in samples fermented with B. subtilis (40.36 %). The trypsin inhibitor in the raw seeds (38.02 mg/g) reduced to 17.54 mg/g after natural fermentation for 72 h. ‘Iru’ fermented with B. subtilis exhibited the highest antioxidants effect except in 2, 2’-azino-bis (3-ethylbenthiazoline-6-sulphonic acid) (ABTS) where the iru fermented with L. mesenteroides was the highest with a value of 0.0204 mg/g. Only sample fermented with L. mesenteroides showed the presence of copper (0.23 mg/g) after fermenting for 72 h. Sensory evaluation of the iru samples revealed that ‘iru’ fermented with B. subtilis and naturally fermented were well accepted by consumers. The amino acid profile showed that the ‘iru’ fermented with B. subtilis had the highest aspartic acid with a value of 25.89 g/100g, while tryptophan was found to be highest in ‘iru’ fermented with L. mesenteroides (0.94 g/100g). The fatty acid profile showed that lauric acid was absent in the raw seed but present in all the fermented seeds. Linoleic acid was highest in the iru fermented with L. plantarum with a value of 42. 99 %. In the animal assay, the iru fermented with L. plantarum reduced the cholesterol in rats from 100.80 mg/dl to 56.99 mg/dl which was significantly lower (P ≥ 0.05) than the untreated (119.45 mg/dl). The group fed with L. plantarum also had the least triglyceride with a value of 32.56 mg/dl compared to the untreated group (124.57 mg/dl). Aspartate aminotransferase (AST) level in rats not fed with iru was significantly higher (P ≥ 0.05) with a value of 89.21 U/l compared to all other groups. The haematological results showed that there was no significant difference (P ≥ 0.05) in the packed cell volume (PCV) in all the groups. The results from this study revealed that iru obtained by fermenting P. biglobosa seed with L. Plantarum significantly reduced the cholesterol level in rats fed iru supplemented diet without any sign of toxicological effect. The fermented P. biglobosa product, ‘iru’ could be employed in the management of cardiovascular disease (CVD) caused by high blood cholesterol