Assessment Of Biological And Physicochemical Properties Of Polyphenols And Fibers In Cocoa Shell

Cocoa and its related product are widely consumed globally. Processing of cocoa into finishedproducts is associated of generation huge tons of industrial wastes among which include cocoabean shell. Apart from its utilization as mulch and to a much limited extent as animal feed, cocoabean shell is hardly used in human food, though previous report showed that the materialcontained high nutritive value particularly dietary fiber and polyphenols. Meanwhile, there is anincreasing consumers’ demand for functional foods rich in particularly, dietary fiber andpolyphenol in recent times. It therefore stimulates the thinking that cocoa bean shells (CBS) maybe readily cheap source of these compounds for food formulations. Consequently, this study wasinitiated to investigate the potential biological activity in relation to antioxidant activity,hypoglycemic and hypocholesterolemic and physicochemical functional properties relative to itspolyphenols and dietary fibers.In this research work, the report focuses on two main parts. In the first part, ethanol, acetone,methanol,(80%v/v) and water were used to extracts polyphenols from CBS and each subjectedto in vitro antioxidant test using three different assays (2,2-diphenyl-1-picrylhydrazylradical(DPPH), β-carotene linoleic acid and ferric reducing/antioxidant power (FRAP)). Total phenoliccontent and total flavanoid content in each extract was also quantified by colorimetric meanswhile their major compounds were separated and quantified by HPLC.Acetone yielded the highest total phenolic content (41.82mg gallic acid equivalence (GAE)/gdry weight [dw]) followed by methanol (25.36mg GAE/g dw), ethanol (23.36mg GAE/g dw)and water (17.21mg GAE/g dw). Surprisingly, water extract exhibited the highest antioxidantactivity based on DPPH and β-carotene linoleic acid assays implying that the aqueous extractcontained high amount of free antioxidant compared with the organic solvents. However, allextracts exhibited DPPH free radical scavenging activity above80%and were comparable to thatof ascorbic acid (85%). A positive correlation between total phenolic content and antioxidantactivity was observed when extracts were tested by FRAP assay suggesting that the totalantioxidants (bound and free) actively took part in the reducing the FRAP active compound. TheHPLC analysis identified gallic acid, theobromine and caffeine in all the four extracts. However, the predominant compound was theobromine followed by caffeine in all extracts. Waterexhibited excellent extraction efficiency for the phenolic compounds.In the second part, monosaccharide compositions, physicochemical functional properties andbiological activity of CBS soluble dietary fiber (SDF), insoluble dietary fiber (IDF) and totaldietary fiber (TDF) powder concentrates were investigated. SDF contained over83%non-starchpolysaccharide (NSP), while IDF and TDF concentrates contained42%Klason lignin and51%NSP respectively as their major constituents. Seven monosaccharides (fucose, rhamnosearabinose galactose, glucose, xylose, and mannose) were identified in each fiber concentrate,with galactose (20.45%) being major constituent of the neutral sugars in SDF, while both IDFand TDF contained8.64%13.24%glucose respectively, as chief neutral sugar. Physicalcharacteristics, hydration properties oil binding capacity of the concentrates were similar to othernatural DF.For the biological activity, the three fiber products were evaluated for their effects on glucoseadsorption, glucose diffusion, starch hydrolysis, cholesterol binding, sodium cholate binding andoil binding capacities using in vitro model systems by simulating gastric intestinal conditions.The results showed that SDF generally exhibited significantly (p<0.05) higher glucoseadsorption capacity (GAC), α-amylase inhibition activity, cholesterol, sodium cholate and oilbinding capacity, but less significant (>0.05) glucose dialysis retardation index (GDRI) and oilbinding capacity, when compared with IDF and TDF which both showed similar effects.Moreover, it was discovered that the three CBS dietary fiber powders contained intrinsicantioxidants (phenolic compounds) as demonstrated by the TEAC and ABTS methods. Thus,CBS fibers could be incorporated as low calorie bulk ingredients in high-fiber diet to reducecalorie and cholesterol levels and control blood glucose level.