Hydroxymethylfurfural content, diastase activity and colour of multifloral honeys in relation to origin and storage time

Celem pracy było porównanie jakości miodów wielokwiatowych dostępnych na polskim rynku detalicznym w zależności od ich pochodzenia (krajowe vs. zagraniczne) oraz czasu przechowywania (przed lub po upływie daty minimalnej trwałości). Badaniami objęto 24 próby miodów wielokwiatowych, w tym krajowe (tj. niekonfekcjonowane zakupione na bazarach bezpośrednio od pszczelarzy i nabyte w detalicznej sieci handlowej) i zagraniczne (z krajów członkowskich Unii Europejskiej i spoza niej) zakupione w hipermarketach. Dodatkowo oceniono 5 prób zakupionych wcześniej miodów, dla których minęła już data ich minimalnej trwałości. W miodach oznaczono zawartość 5-hydroksymetylofurfuralu (5-HMF), wartość liczby diastazowej (LD) oraz barwę wg CIE L*a*b*. W świeżych miodach wielokwiatowych (niezależnie od pochodzenia) zawartość 5-HMF wahała się od 1,17 do 18,54 mg·kg-1 , a wartość LD od 8,36 do 34,88. Tym samym wszystkie próby spełniały ustawowe wymagania (8 wg skali Schade dla LD). Wykazano istotne (P≤0,01) obniżenie jakości miodów po upływie daty minimalnej trwałości. Przeciętna zawartość HMF (93,87 mg·kg-1) była dwukrotnie większa niż wartość dopuszczalna, podobnie średnia wartość LD (6,45) była niższa od przyjętego limitu. Wykazano istotne różnice (P≤0,01) pomiędzy średnimi wartościami wszystkich parametrów barwy miodów w zależności od czasu przechowywania. Barwa miodów po upływie daty minimalnej trwałości była istotnie ciemniejsza i o mniejszym nasyceniu (L*=43,18 i C*=21,23) w porównaniu do miodów świeżych (L*=62,11 i C*=32,66).The aim of the study was to compare the quality of multifloral honeys in relation to origin (domestic vs. foreign), and storage time (before vs. after the date of minimum durability) available on the Polish retail market. The study was conducted on 24 samples of multifloral honey, including domestic ones (i.e. originated directly from beekeepers in open-air markets, or purchased in a retail chain), and foreign (i.e. from inside or outside the EU) bought in hypermarkets. In addition, the study comprised 5 samples of honey after the date of minimum durability. The content of hydroxymethylfurfural (5-HMF), diastase number (DN) and colour according to CIE L*a*b* were determined in honeys. In the fresh multifloral honeys (irrespective of origin) the content of 5-HMF ranged from 1.17 to 18.54 mg·kg-1, and DN ranged from 8.36 to 34.88. Thus all samples met the legal requirements (5-HMF<40 mg·kg-1 and DN<8 on the Schade scale). Significant (P≤0.01) deterioration in the quality of the honey was noted after the date of minimum durability. The mean HMF content (93.87 mg·kg-1) was twice as high as the acceptable value, and the mean DN (6.45) was lower than the accepted limit. Significant differences (P≤0.01) were noted between mean values for all colour coordinates considering the date of minimum durability. The colour of the honey after the date of minimum durability was significantly darker and had lower saturation (L*=43.18 and C*=21.23) than the fresh honey (L*=62.11 and C*=32.66)

Application of FTIR spectroscopy for analysis of the quality of honey

Every kind of honey is a very precious natural product which is made by Mellifera bees species. The chemical composition of honey depends on its origin or mode of production. Honey consists essentially of different sugars, predominantly fructose and glucose. There are also non – sugar ingredients like proteins and amino acids, as well as some kind of enzymes, such as: invertase, amylase, glucose oxidase, catalase and phosphatase. The fact that honey is one of the oldest medicine known worldwide is remarkable. Scientists all over the world have been trying to improve analytical methods as well as to implement new ones in order to reaffirm the high quality of honey the benefits of which may be distracted or disturbed. There are many methods and popular analytical techniques, including as follows: mass spectroscopy and molecular spectroscopy (especially FTIR spectroscopy). The infrared spectroscopy technique is one of the most common analytical methods which are used to analyse honey nowadays. The main aim of the task was to use ATR-FTIR infrared spectroscopy to compare selected honey samples as well as typical sequences coming out from certain functional groups in the analysed samples

Application of FTIR spectroscopy for analysis of the quality of honey

Every kind of honey is a very precious natural product which is made by Mellifera bees species. The chemical composition of honey depends on its origin or mode of production. Honey consists essentially of different sugars, predominantly fructose and glucose. There are also non – sugar ingredients like proteins and amino acids, as well as some kind of enzymes, such as: invertase, amylase, glucose oxidase, catalase and phosphatase. The fact that honey is one of the oldest medicine known worldwide is remarkable. Scientists all over the world have been trying to improve analytical methods as well as to implement new ones in order to reaffirm the high quality of honey the benefits of which may be distracted or disturbed. There are many methods and popular analytical techniques, including as follows: mass spectroscopy and molecular spectroscopy (especially FTIR spectroscopy). The infrared spectroscopy technique is one of the most common analytical methods which are used to analyse honey nowadays. The main aim of the task was to use ATR-FTIR infrared spectroscopy to compare selected honey samples as well as typical sequences coming out from certain functional groups in the analysed samples