The composition and bacteriostatic activities of fifteen propolis samples from various botanic and geographic origins were determined. Twenty‐six phenolic components were identified by high‐performance liquid chromatography with array photodiode detector. Acacetin and apigenin were most abundant. Pinocembrin, quercetin, rutin and vanillin were present in lesser quantities. Variance analysis shows significant differences (P≤0.05) in the contents of phenols, flavonoids and active components. The minimum inhibitory concentration of propolis is about 53 times higher than that reported for tetracycline againstBacillus subtilis andStaphylococcus aureus, and about 400 times higher againstEscherichia coli.

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Flavonoids and other phenolic compounds were determined in 15 samples of propolis originating from China, from Brazil, and from Uruguay. A total of 24 compounds were identified using mainly HPLC and a few other analytical methods. The most abundant compounds found were benzoic acid and benzaldehyde derivatives, flavones, flavonols. and flavanones. 80% of the samples contained at least 22 g/100 g of flavonoids, primarily acacetin, isorhamnetin, apigenin, and pinocembrin. The flavonoid patterns were sufficiently distinctive to permit discrimination between propolis from China, from Uruguay, and from Brazil.

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The cocoa roasting process at different temperatures (at 125 and 135 degrees C for 3 min, plus 44 and 52 min, respectively, heating-up times) was evaluated by measuring the initial and final free amino acids distribution, flavor index, formol number, browning measurement, and alkylpyrazines content in 15 cocoa bean samples of different origins. These samples were also analyzed in manufactured cocoa powder. The effect of alkalinization of cocoa was studied. Results indicated that the final concentration and ratio of tetramethylpyrazine/trimethylpyrazine (TMP/TrMP) increased rapidly at higher roasting temperatures. The samples roasted with alkalies (pH between 7.20 and 7.92), such as sodium carbonate, or potassium plus air injected in the roaster during thermal treatment, exhibited a greater degree of brown color formation, but the amount of alkylpyrazines generated was adversely affected. The analysis of alpha-free amino acids at the end of the roasting process demonstrated the importance of the thermal treatment conditions and the pH values on nibs (cocoa bean cotyledons), liquor, or cocoa. Higher pH values led to a lower concentration of aroma and a higher presence of brown compounds.