Tag Archives: honey

1717–1726 A. Keke and I. Cinkmanis
Changes in α-amylase activity in honey during the freeze-drying process
Abstract |
Full text PDF (280 KB)

Changes in α-amylase activity in honey during the freeze-drying process

A. Keke* and I. Cinkmanis

Latvia University of Life Sciences and Technologies, Faculty of Food Technology, Department of Chemistry, Liela Street 2, LV-3001 Jelgava, Latvia
*Correspondence: anete.keke@llu.lv

Abstract:

Honey is a natural product, which is appreciated for its sweetness, high nutritional value and health benefits all over the world. Despite all benefits, the usage of honey in food industry is limited due to its high viscosity. The use of dried honey could be an alternative to liquid honey, and would allow to use it as an additive in a range of many different food products such as sauces, beverages, yogurts etc. There are many parameters, which are used to determinate the quality of honey. α-amylase (diastase) activity is one of the most important criteria to determine the quality and freshness of honey. The aim of the present study was to investigate and compare α-amylase activity in liquid honey samples and freeze-dried honey samples. Overall, 18 honey samples were dehydrated using a freeze-drying method. Freeze-drying of the samples was carried out at – 50.6 °C and the pressure was 0.036 mbar for 72 hours. α-amylase activity in the honey samples was tested using Amylazyme test tablets. The obtained results showed variability in α-amylase activity after the freeze-drying process. As hydroxymethylfurfural (HMF) is another important quality parameter of honey, the content of HMF was determined in the samples by high performance liquid chromatography. In some samples the concentration of HMF after freeze-drying increased and was higher than it is allowed according to the International Honey Commission (for example, 55.75 mg kg-1).

Key words:

, , ,




720–728 T. Jehlička
Modification of the rheological properties of honey in the honeycombs by the high frequency heating prior to honey extraction
Abstract |

Modification of the rheological properties of honey in the honeycombs by the high frequency heating prior to honey extraction

T. Jehlička

Czech University of Life Sciences Prague, Faculty of Engineering, Department of Technological Equipment of Buildings, Kamýcká 129, CZ165 21 Prague 6 – Suchdol, Czech Republic
Correspondence: Jehlickat@tf.czu.cz

Abstract:

This paper addresses the issue of the extraction of highly viscous honey from the honeycombs. High viscosity can be caused by many factors. In the operational practice it is mainly about the difficult conditions (cold weather), post seasonal honey extraction or honey with naturally high viscosity (honeydew honeys). The objective was to design and validate a technology that will enable to reduce the viscosity of honey in the honeycombs by the high frequency heating and increase the effectiveness of honey extraction. The experimental part is based on the high frequency heating of honey, so called dielectric heating. In this process the heating of honey occurs evenly throughout the full volume of the honeycomb. To verify the proposed procedure, several groups of samples of the capped honeycombs were selected that contained honey of different botanical origin and rheological properties. For heating of the honeycombs, a high frequency chamber was prepared in the laboratory conditions. Honeycombs were placed into the chamber and heated to the desired temperature (from 15 °C to 45 °C). During extraction, the time dependence of honey extraction on the temperature of the pre-heated honeycombs was monitored. It was proved that the high frequency heating is suitable for the pre-processing of the honeycombs; heating is quick and reduces the viscosity. As a consequence of different permittivity of honey and beeswax, the strength of the comb is not changed when the electromagnetic field conditions are set properly, the honeycomb remains compact. Measurements demonstrated the time reduction of honey extraction based on the temperature.

Key words:

, ,




1293-1299 T. Jehlička and J. Sander
Modification of the rheological properties of the honey in the honeycombs prior to its extraction in the production conditions
Abstract |
Full text PDF (767 KB)

Modification of the rheological properties of the honey in the honeycombs prior to its extraction in the production conditions

T. Jehlička¹* and J. Sander²

¹Czech University of Life Sciences Prague, Faculty of Engineering, Department of Technological Equipment of Buildings, Kamýcká 129, CZ 165 21 Prague 6 – Suchdol, Czech Republic
²Czech University of Life Sciences Prague, Faculty of Engineering, Department of Technological Equipment of Buildings, Kamýcká 129, CZ 165 21 Prague 6 – Suchdol, Czech Republic
*Correspondence: jehlickat@tf.czu.cz

Abstract:

This paper addresses the issue of honey extraction in difficult conditions (prevailing cold weather) and the extraction of highly viscous honey from the honeycombs. The objective was to design and validate a technology that will reduce the viscosity of honey in the honeycombs by warming up by infrared radiation and shorten the total time of honey extraction. To verify the proposed procedure three groups of samples of the capped honeycombs were selected that contained honey of different botanical origin and rheological properties. The honeycombs were warmed up to the targeted temperature (from 15 °C to 40 °C). Warming was carried out by two low-temperature emitters of the infrared radiation. The time dependence of honey extraction on the temperature of the pre-heated honeycombs was monitored. The measured values indicate that the dependence of the rheological properties of honey on temperature is technologically significant. Operational monitoring shown that the optimal rheological properties for the processing of the honeycombs are at a temperature above 30 °C as the time necessary for the honeycombs extraction reaches its minimum value. The optimal temperature for the honeycomb extraction can be considered the temperature above 30 °C which corresponds to the extraction time for about 4 minutes. The evaluation of the obtained results demonstrates the operational reliability of the proposed technology. Measurements proved that the infrared radiation is suitable for warming up of the honeycombs, warming up is quick and results in time reduction of honey extraction from honeycombs is dependent on temperature.

Key words:

, , ,