Honey enzyme

The diastase activity was traditionally determined according to the Schade method in the earlier years (Schade et al., 1958). One unit of diastase activity (or more specifically, a-amylase), DN, is defined as that amoimt of enz)nne that converts 0.01 g of starch to the prescribed endpoint in 1 h at 37 °C under the experimental conditions. In this assay, a standard solution of starch, which reacts with iodine to produce a color solution, is used as a substrate for honey enzymes under the standard conditions (Rendleman, 2003). A recently developed procedure uses an insoluble, dyed starch substrate (Persano Oddo and Pulcini, 1999). As this substrate is hydrolyzed by ot-amylase, soluble dyed starch fragments are released into solution. After reaction termination and insoluble substrate removal by centrifugation, absorbance of the supernatant solution (at 620 nm) is measured. The absorbance is proportional to the diastase activity. This procedure has been widely adopted in the honey industry due to the convenience of a commercially available substrate and the simple assay format. 

In nature, fmctose (levulose, fmit sugar) is the main sugar in many fmits and vegetables. Honey contains ca 50 wt % fmctose on a dry basis. Sucrose is composed of one unit each of fmctose and dextrose combined to form the disaccharide. Fmctose exists in polymeric form as inulin in plants such as Jemsalem artichokes, chicory, dahlias, and dandeHons, and is Hberated by treatment with acid or enzyme. 

In the body, this reaction is reversed by the enzyme sucrase. This occurs in digestion, which makes glucose and fructose available for absorption into the blood. Honey bees also carry an enzyme that can hydrolyze sucrose. Honey consists mostly of a 1 1 mol mixture of glucose and fructose with a small amount of unreacted sucrose. 

Caramel color interacts with other food components. As an example, a concentration higher than 700 ppm caramel in cola increased the rate of hydrolysis of the aspartame, forming alpha-L-aspartyl-L-phenylalanine. Caramelization products inhibited enzymic browning by 85.8 and 72.2% when heated at pH 4 and 6, respectively, for 90 min. The highest inhibitory activity was found for the fraction with molecular weight of 1000 to 3000. Caramel is often used for adulteration of juices and other foods like honey or coffee. It can be determined by quantification of marker molecules such as 5-HMF, 4-Mel, and DFAs. ... 

Enzyme activity can indicate the exposure of honey to heating and long storage. This criterion is not more accurate than the HMF content value because enzyme activities vary with honey samples. The diastase activity is usually associated with heat treatment. However, its activity gives only an indication about the processing (heat treatment) of the honey but is not suitable for the detection of the origin. 

Each plant tissue tends to have an obviously distinctive profile of flavonoids. The flavonoid content can reach about 0.5% in pollen, 10% in propolis, and about 6 mg/kg in honey. Havonoid aglycones appear to be present only in propolis and honey, while pollen contains flavanols in herosidic forms. The flavonoids in honey and propolis have been identified as flavanones and flavanones/flavanols (Campos et ah, 1990). The antimi-crobially active flavanone pinocembrine was foimd to be a major flavonoid in honey (Bogdanov, 1989). Amiot et ah (1989) studied two blossom and two honeydew Swiss honey samples and foimd that pinocembrine was the main flavonoid. Pinocembrine concentration varied between 2 and 3 mg/kg (Bogdanov, 1989). Berahia et ah (1993) analyzed sunflower honey samples and detected six flavone/flavols, four flavanone/ flavols, and pinocembrin, of which pinocembrin is the main flavonoid. The flavonoids in sunflower honey and propolis were characterized and assessed for their effects on hepatic drug-metabolizing enzymes and benzo [fl]pyrene-DNA adduct formation (Sabatier et ah, 1992 Siess et ah, 1996). 

Persano Oddo, L. and Pulcini, P. (1999). A scientific note on the Phadebas method for honeys with low enzyme content. Apidologie 30, 347-348. 

Siess, M. H., Le Bon, A. M., Canivenc-Lavier, M. C., Amiot, M. ]., Sabatier, S., Yaubert, S. Y., and Suschetet, M. (1996). Flavonoids of honey and propolis Characterization and effects on hepatic drug-metabolizing enzymes and benzoja] pyrene-DNA.. Agric. Food Chem. 44, 2297-2301. 

Tourn, M. L., Lombard, A., Belliardo, F., and Buffa, M. (1980). Quantitative analysis of carbohydrates and organic acids in honeydew, honey and royal jelly by enzymic methods. J. Apicult. Res. 19,144 146. 

Voldrich, M., Rajchl, A., and Cizkova, H. (2009). Detection of Eoreign enzyme addition into the adulterated honey. Zech.. Food Sci. 27, S280-S282. 

Vorlova, L. and Elechovska, O. (2002). Activity of enzymes and trace element content in bee honey. Acta Vet. Brno. 71, 375-378. 

Fructose is found in honey and fruit and as part of the disaccharide sucrose (common table sugar). Sucrose is hydrolyzed by intestinal brush border sucrase, and the resulting monosaccharides, glucose and fructose, are absorbed into the portal blood. The liver phosphorylates frurtose and cleaves it into glyceraldehyde and DHAP. Smaller amounts are metabolized in renal proximal tubules. The pathway is shown in Figure 1-12-7 important enzymes to remember are ... 

In most European countries, honey is defined in similar terms. However, certain quality factors considered by Europeans, especially the Germans, of importance in the marketing of honey are the levels of the enzymes invertase and diastase, and of 5-(hydroxymethyl)-2-furaldehyde. White has discussed these requirements in relation to suggested standards for the Codex Alimentarius.32 The German insistence on these requirements is outlined in a volume of Apiacta.33... 

As regards the occurrence of /3-D-linked disaccharides in the absence of a /3-D-linked substrate, one is tempted to conclude that these oligosaccharides are synthesized by the enzymic reversion of D-glucose by a /3-D-glucosidase. As White and Maher100 have found that their honey-invertase preparation had no /3-D-glucosidase activity, it would appear that these sugars are carried into the hive as constituents of nectar. 

In vitro syntheses with enzymes almost invariably result in poor yields, but use of such syntheses is essential when chemical syntheses have not yet proved feasible. Another advantage of enzymic processes lies in their similarity to the processes occurring in Nature. It is implicit that similar enzymes or similar enzymic reactions are operative in the formation of honey, but, unfortunately, our knowl-... 

Adipic acid (0.60 mol) and an oligomeric glycerol having a repeat unit of three, PG-3 (0.44 mol), were dissolved at 70°C in 80 ml of toluene and then treated with enzyme catalyst Novozym -435 (14 g). The mixture was polymerized for 9 hours at 70°C at 300 mbar to remove water formed during the reaction. The mixture was then concentrated and the product isolated as a honey-like, viscous, colorless to slightly yellowish polyester. The polyester was readily soluble in water. 

---