A novel technology to process traditional chocolate-making ingredients has been investigated with the main objective to promote the generation of key chocolate odorant volatiles as a part of the commercial interest of the industrial partner to create a new line of natural products with intense chocolate flavour. The novel technology is based on the thermal generation of flavours (non-enzymatic browning) using a closed-batch reactor that is able to hold six bars of overpressures, speeding up the aromatic reactions, and the use of enzymes to increase the flavours precursors. Pilot scale experiments were carried using sugars, cocoa powder and water in various ratios and were submitted to temperatures from 70°C to 130°C during various reaction times (1 to 10 hours) reaching over pressures from 0.2 to 3.5 bars. The assessment of the evolution of the products obtained was carried out chemically and sensorially. Chemically, using a laboratory-developed headspace solid phase microextration gas chromatography mass spectrometry (HS-SPME-GC-MS) methodology and sensorially with a trained panel of tasters. Temperatures of 130°C with enzymatic pre-treatment of the cocoa resulted with the highest generation of volatiles scoring the maximum in the aromatically but on the other hand 90°C, without enzymatic pre-treatment, had the best taste evaluation.

Citrus essential oils (EO) are potential antimicrobials, first described as such in 1949 by Piacentini. Due to their acceptability in terms of fragrance and flavour characteristics, they lend themselves to use both in food and in clinical practice. Lemon (Citrus limon) or sweet orange (Citrus sinensis) or bergamot (Citrus bergamia) essential oils and their components (limonene, linalool, citral, hersipidin and neoericitrin) and vapours at different temperatures and pHs were tested for their anti-microbial activity against vancomycin-sensitive Enterococcus faecium and Enterococcus faecalis. Lemon essential oil alone or blended and orange EO alone were not as effective as citral or linalool alone or bergamot blends with inhibition diameters of > 9cm. The ranges established for differences in inhibition of growth were; 5-15°C, 20-25°C, 30-45°C and 50°C (p ≤ 0.005) and pHs 4.5-6.5, pH 7.5, and pHs 8.5 —10.5 (p ≤ 0.001). A blend of 1:1 (v/v) orange/bergamot EO was the most effective with MICs at 25°C and pH 5.5 of 0.25% - 0.5% (v/v) and an MID of 50mg/i at 50°C at pH 7.5, under these conditions viable counts were reduced by 5.5 - 10 log10 cfu/ml (p ≤ 0.001). The mechanisms by which a blend of orange/bergamot EO and its vapour bring about their antimicrobial effect were assessed. Transmission electron microscope (TEM) images established morphological changes as well as suggesting EO blend uptake into the cell. The permeability of the cell increased by x2 after being subjected to the EO and by x40 after exposure to the vapour. There were decreases of 1.5 in intracellular pH, 20 a.u. in membrane potential and 18 pmol/mg protein of intracellular ATP. The application of the EO blend impregnated into wipes reduced surface microbial load of vancomycin resistant and vancomycin susceptible E. faecium and E. faecalis by up to 4 log10 compared with control wipes (p ≤ 0.00 1). The use of the EO blend vapour on surfaces resulted in a 2.5 log10 reduction over 24 hours, whilst the vapours (15mg/L air) showed a microbial reduction of up to 4 log10 on cucumber skin and lettuce leaf after 45 seconds exposure via a heat diffuser at 25°C (p ≤ 0.001). Sensory tests demonstrated that there were no changes to the taste of the foodstuff after treatment with the EO blend vapour compared with untreated controls. Investigations into the applications of the EO blend showed no significant difference in effect of EO blend between vancomycin resistant and vancomycin susceptible strains. The results of this study suggest that the use of a citrus essential blend both in oil and vapour form could be a potential alternative to chemical based antimicrobial

During the past two decades several novel spoilage micro-organisms have emerged. Raw materials and products have been contaminated in increasing numbers of spoilage incidents causing widespread problems within the juice and beverage industry. This study investigates two such spoilage micro-organisms, A licyclobacillus acidoterrestris and Propionibacterium cyclohexanicum, both isolated from pasteurised contaminated fruit juice. A variety of media were tested to determine which supported optimal growth of A. acidoterrestris with Orange Serum Agar providing consistently high plate counts. The presence of A. acidoterrestris in raw materials and shelf stable products was monitored and the effects on its growth and survival of temperature, headspace and movement of containers during storage were investigated. The survival of P. cyclohexanicum after pasteurisation was assessed and growth determined at a variety of temperatures. The survival of each bacterium was investigated in different fruit juices, when challenged by the preservatives sodium benzoate and potassium sorbate and the bacteriocin nisin and when grown in the same juice container and co-cultured on the same solid medium. 17% of samples tested were contaminated by A. acidoterrestris; however P. cyclohexanicum was not isolated from any sample. P. cyclohexanicum survived 10 minutes at temperatures of 4°C to 95°C and grew in orange, tomato and pineapple juice while A. acidoterrestris grew in all juices tested. A. acidoterrestris was inhibited by sodium benzoate (500ppm), potassium sorbate (500ppm) and nisin (51U/ml). P. cyclohexanicum, although not inhibited by nisin (1000IU/ml), was susceptible to sodium benzoate (500ppm) and potassium sorbate (l000ppm). I-Ieadspace, movement of containers and storage temperatures affected detection rates of A. acjdoterrestrjs. Co-cultures demonstrated that if found within the same enviromnent, both bacilli can survive and cause spoilage. A. acidoterrestris is a world wide contaminant within the soft drinks industry and, considering the results of these studies P. cyclohexanicum with its heat resistance and tolerance to nisin may also emerge as a major spoilage microorganism