Effect of Thermal Processing on Antibacterial Activity of Multifloral Honeys

Abstract

In this study, the effects of thermal processing in the antibacterial activity of four multifloral honeys were determined. The thermal treatments were carried out at 30, 40, 50, 60, 70 and 80C, and the following characteristics were determined: total phenols and antibacterial activity of three gram-positive bacteria (Bacillus subtilis, Staphylococcus aureus and Listeria monocytogenes) and three gram-negative bacteria (Escherichia coli, Salmonella typhimurium and Pseudomonas aeruginosa). The results showed that the behavior of total phenols in relation to temperature depended on the floral sources of honey. The honeys presented curves of either linear or quadratic responses of the antibacterial activity in relation to the thermal process, depending on the honey's floral sources and the kind of bacterium to inhibit. The results suggest that the honey's antibacterial activities and behavior with the temperature are different depending on the honey's floral sources and the kind of bacteria that they inhibit. PRACTICAL APPLICATIONSThe consumer trend to search for minimally processed foods has increased in recent years due to the perception that food processing decreases its health benefits and antibacterial activities. Honey can inhibit pathogenic bacteria, but this inhibition is determined by the floral source from which the honey is collected. In this study, it was shown that thermal processing has a different effect on the antibacterial activities of each honey. These effects were linear or quadratic according to the bacteria (Bacillus subtilis, Staphylococcus aureus, Listeria monocytogenes, Escherichia coli, Salmonella typhimurium and Pseudomonas aeruginosa) and the floral source of the honey. This effect did not depend on the Gram (the inhibition against Salmonella typhimurium was linear with respect to the thermal process in all honey), in contrast to E. coli (where the effect was quadratic with a peak at 60C in all of the honey). The results led to the conclusion that the thermal processing of each honey must be different to maximize their beneficial health effects as well as their antibacterial activities.

Antioxidant Activity and Volatile Composition of Red Araçá Pulp Under Different Drying Conditions

“…Based on the results from Table 2, an Arrhenius-type dependence was observed between the drying temperature and the effective mass diffusivity of the red araçá fruit. D eff ranged from 8.542 × 10 −8 to 13.34 × 10 −8 m 2 /min, in accordance with the values found in the literature for other fruits, such as pineapple [16], banana [11], and fig [17]. Figure 1 shows the experimental and simulated drying kinetics for all three drying temperatures (40, 50, and 60°C).…”

“…erefore, the effect of drying on the chemical composition of dried fruit extracts is of vital technological and nutritional importance [11]. In view of the above, the present work aimed at mathematically modeling the thin-layer drying of araçá and at evaluating possible alterations of antioxidant activity and volatile composition of red araçá extracts submitted to different convective drying conditions.…”

Application of Heating on the Antioxidant and Antibacterial Properties of Malaysian and Australian Stingless Bee Honey

“…The liquefaction process at a temperature of 55 °C and the pasteurisation process are the two stages used in the honey industry to ensure that the honey remains in liquid form for an extended period, impairing the crystallisation nuclei [ 13 ]. However, a high temperature can affect the physicochemical properties of honey during processing [ 14 ], and this research will study the effect of heat treatments at temperatures of 45 °C, 55 °C, and 65 °C on the antioxidant and antibacterial activities of stingless bee honey from four different species and two different countries.…”

Optical Determination of the Effects by Thermal Treatment (TT) in Honey of <i>Apis mellifera</i> Bees

“…The wavelengths included in the UV-Vis and NIR [8] zones were those selected for the execution of optical analysis that could show the effects that the Thermal Treatment technique causes on honey, when it is used for tasks to de-crystallize and/or eliminate microorganisms that induce fermentation [9], significantly reducing the shelf life, mainly in honeys that have been harvested before their complete maturation. Figure 3 shown below describes the preparation process of the equipment that allows obtaining the information for the construction of the spectral graphs of the analyzed honey samples.…”