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Polyphenolic compounds extraction from industrial apple pomace was optimised by applying design of experiments (DoE) and surface response methodology using the Central Composite Rotatable Design (CCRD). The degree solubilisation and the yield of total phenolic content from the apple pomace using organic solvents was shown to be influenced by process parameters including solvent type, solvent concentration, temperature, apple pomace to solvent ratio, and extraction time (residency time). Optimal conditions of extracting phenolic compounds were as follows: acetone concentration, 65 % (v/v); solid to solvent ratio 1 %; extraction time 30 minutes and temperature 60oC. Optimum condition for solubilisation was as follows: acetone concentration 78 % (v/v); solid to solvent ratio 4.7 %; extraction time 54 minutes and temperature 21oC. Under these conditions, the total phenolic content and solubilisation were 21.70 ± 0.2 mg GAE/g dw and 19.20 ± 0.1g/100g of the dried apple pomace respectively and largely agreed with those predicted by the Stat-Ease software. Independent variables for optimisation of total phenolic content and solubilisation were completely different. The reverse phase HPLC analysis of the extract revealed the major polyphenolic compounds were chlorogenic acid, procyanidin B2, caffeic acid, epicatechin, ferulic acid, quercetin-3-galactoside, quercetin-3-glucoside and phloridzin.

Polyphenolic compounds with relatively high antioxidant activity obtained from subcritical water extraction of apple pomace were assessed for encapsulation by spray drying technique, making use of polymeric substances co-extracted with the polyphenolic compounds. Comparative assessments were carried out of the directly encapsulated subcritical water extract (SWE) products with particles formed when encapsulated with the addition of hydroxyl propyl-β-Cyclodextrin (SWE + HPβ-CD). The powders were characterized for their physico-chemical properties such as, moisture content, density, particle size, hygroscopicity to assess their suitability within cosmetic formulations. The SWE and SWE + HPβ-CD encapsulated products resulted in different physical properties. Although the particle size was less than 4 μm for both products, the direct encapsulation (SWE) was highly hygroscopic and this property was significantly reduced with addition of HPβ-Cyclodextrin (SWE + HPβ-CD). Scanning electron microscopy (SEM) and Fourier Transform Infra-red (FT-IR) spectroscopic were employed to analyse the micronised powders to support evidence of encapsulation. Both techniques revealed the interaction between compounds in extract and the carrier HPβ-Cyclodextrin suggesting successful encapsulation. The effect of storage conditions on retention of antioxidant activity of the subcritical water extract was evaluated within 35 days for extracts with and without the carrier HPβ-Cyclodextrin. Hydroxyl propyl-β-Cyclodextrin offered protection against degradation of antioxidant compounds thereby potentially extending the shelf-life and making the encapsulated powder suitable for incorporation in cosmetic and pharmaceutical applications.

This present study compared antioxidant and antimicrobial activities of acetone and water extracts of Theobroma cacao beans against Escherichia coli. Total phenolic content (TPC) in both extracts was estimated by the Folin-Denis reagent. The present study showed that the 70% (v/v) acetone extract had a higher extraction yield and TPC (37% and 109 mg TAE g −1 dry weight) than the water extract (33% and 76 mg TAE g −1 dry weight). The antioxidant activities of both extracts were estimated by the DPPH Scavenging Assay. The extract obtained using 70% (v/v) acetone showed higher antioxidant activity (54%) compared to the antioxidant activity obtained using water (34%). Antimicrobial activities of acetone and water extracts from Theobroma cacao were measured against Escherichia coli and were screened by agar well diffusion method and further confirmed with the disc diffusion method. The bacterial growth was measured in Mueller Hinton agar. The extracts inhibited the growth of the Escherichia coli cultured, and the acetone extracts showed antimicrobial capacity comparable or equivalent, as seen in commercial ampicillin.

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