Effect of high hydrostatic pressure on antimicrobial activity and quality of Manuka honey

High‐pressure processing of Manuka honey: brown pigment formation, improvement of antibacterial activity and hydroxymethylfurfural content

“…The highest temperature of 70 °C exhibited the lowest percentage inhibition. This is in agreement with Al‐Habsi & Niranjan () who found that honey losses its antibacterial activity when exposed to higher temperature. Likewise, Rios et al .…”

“…HMF concentration in HPP‐treated samples at ambient temperature showed the lowest HMF content (16.93–18.76 mg kg −1 ) as compared to other treatments. This is in agreement with earlier study (Al‐Habsi & Niranjan, ) where HPP operating at 25 °C for different pressure levels did not influence HMF concentration. A possible explanation for this is that high pressure has insignificant effect on acid‐catalysed dehydration of hexose, the reaction in which HMF is formed.…”

“…Although Al‐Habsi & Niranjan () suggested the condensation reaction of DHA might have occurred during HPP which then leads to the increase of methylglyoxal, MGO (compound responsible for antibacterial activity), Grainger et al . () have shown that HPP does not accelerate the conversion of DHA to MGO.…”

“…This observation showed that development of brown colour is strongly dependent on temperature (Vaikousi et al ., ), and an increase in brown pigment is related to the increasing of the antibacterial activity (Aljadi & Yusoff, ). However, some studies reported the contradictory effect where at higher temperature, the antibacterial activity was decreased (Al‐Habsi & Niranjan, ), which might be due to the decreases in enzymatic activity. With regard to high pressure, HPP‐treated samples at ambient temperature have lower impact on brown formation (0.158–0.170) and showed a significant difference ( P < 0.05) as compared to thermal treatment.…”

“…Although detailed studies on the effect of HPP on quality and safety of varieties of food have already been performed by very large numbers of investigators, the effect of pressure on the high sugar content food such as honey is much less documented. Al‐Habsi & Niranjan (), Akhmazillah et al . () and Fauzi et al .…”